MEASUREMENT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of ET.S. Provisional Patent Application Serial No. 62/592,638 filed on November 30, 2017. The disclosures of the above application are hereby incorporated by reference for all purposes.

BACKGROUND

[0002] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

[0003] Dynamic light scattering (DLS) is an established technique for measuring particle size distribution that utilizes the light scattering by particles undergoing Brownian motion.

However, conventional methods for DLS are relatively slow and have low accuracy in resolving particle size distribution measurements within multi- and single particle species mixtures. For example, in mixtures comprising more than one particle species of varied sizes, derived particle size distribution measurements have low accuracy because the DLS spectrum is often dominated by the larger-sized particle species. In mixtures comprising only a single particle species, derived particle size distribution measurements have low accuracy because the DLS signal detected may be affected by the presence of air bubbles.

SUMMARY

[0004] The present disclosure generally describes techniques for dynamic light scattering (DLS) to determine particle size distribution measurements.

[0005] According to some examples, methods to perform multispectral DLS for particle size distribution measurement are provided. An example method may include performing, by a first apparatus, the multispectral DLS within a mixture that comprises a particle species by directing light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range; directing light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range; and detecting, through a detector, a first DLS signal in response to a scattering of the light of the first wavelength by the mixture and a second DLS signal in response to a scattering of the light of the second wavelength by the mixture. The example method may also include determining, by a processor communicatively coupled to the first apparatus, a particle size distribution of the particle species based on results of the multispectral DLS by receiving the first DLS signal and the second DLS signal from the detector; determining a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution; determining a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution; and determining the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0006] According to other examples, apparatuses to perform sequential multispectral DLS within a mixture that comprises a particle species are described. An example apparatus may include a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range; a second light source configured to sequentially emit light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range; and a detector configured to detect a first DLS signal corresponding to a scattering of the light of the first wavelength by the mixture and a second DLS signal corresponding to a scattering of the light of the second wavelength by the mixture. A particle size distribution of the particle species may then be determined based on a difference between a first particle size distribution yielded from a determined first scattered light intensity of the mixture based on the first DLS signal and a second particle size distribution yielded by a determined second scattered light intensity of the mixture based on the second DLS signal.

[0007] According to further examples, apparatuses to perform parallel multispectral DLS within a mixture that comprises a particle species are described. An example apparatus may include a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range, and a second light source configured to simultaneously emit light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range. The example apparatus may also include a first spectral filter corresponding to the first wavelength to collect the light of the first wavelength scattered by the mixture, a first detector coupled to the first spectral filter and configured to detect a first DLS signal based on the light collected by the first spectral filter, a second spectral filter corresponding to the second wavelength to collect the light of the second wavelength scattered by the mixture, and a second detector coupled to the second spectral filter and configured to detect a second DLS signal based on the light collected by the second spectral filter. A particle size distribution of the particle species may then be determined based on a difference between a first particle size distribution yielded from a determined first scattered light intensity of the mixture based on the first DLS signal and a second particle size distribution yielded by a determined second scattered light intensity of the mixture based on the second DLS signal.

[0008] According to some examples, apparatuses configured to determine a particle size distribution of a particle species within a mixture using multispectral DLS are described. An example apparatus may include a communication interface configured to facilitate

communication between the apparatus, one or more light sources, and a detector, a memory configured to store instructions, and a processor coupled to the communication interface and the memory. The processor may be configured to receive, through the communication interface, a first DLS signal and a second DLS signal, where the first DLS signal and the second DLS signal are detected by the detector in response to a scattering of a light of a first wavelength and a light of a second wavelength by the mixture following a direction of the light of the first wavelength and the light of the second wavelength into the mixture, respectively. The processor may further be configured to determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0009] According to other examples, systems configured to perform multispectral DLS for particle size distribution measurement are described. An example system may include a communication interface configured to facilitate communication between a first apparatus and a second apparatus, where the first apparatus may be configured to perform multispectral DLS in a mixture that comprises a particle species, and the second apparatus may be configured to determine a particle size distribution of the particle species based on results of the multispectral DLS. The first apparatus may include a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range. The first apparatus may also include a second light source configured to direct light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range. The first apparatus may further include a detector configured to detect a first DLS signal corresponding to a scattering of the light of the first wavelength by the mixture and a second DLS signal corresponding to a scattering of the light of the second wavelength by the mixture. The second apparatus may include a memory configured to store instructions and a processor coupled to the memory. The processor may be configured to receive the first DLS signal and the second DLS signal from the first apparatus, determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0010] According to some examples, a method to perform dynamic light scattering (DLS) for particle size distribution measurement is described. The method may include performing, by a first apparatus, the DLS within a mixture that comprises a particle species by directing light of a particular wavelength into the mixture, where the particular wavelength is selected in a first spectral range; and detecting, through an array detector, a plurality of DLS signals in response to a scattering of the light of the particular wavelength by the mixture. The method may also include determining, by a processor communicatively coupled to the first apparatus, a particle size distribution of the particle species based on results of the DLS by receiving the plurality of DLS signals from the array detector; determining a plurality of scattered light intensities of the mixture based on the plurality of DLS signals to yield a particle size distribution; and

determining the particle size distribution of the particle species based on processing the plurality of scattered light intensities of the mixture.

[0011] According to some examples, an apparatus to perform sequential dynamic light scattering (DLS) within a mixture that comprises a particle species is described. The apparatus may include a light source configured to emit light of a particular wavelength into the mixture, where the particular wavelength is selected in a first spectral range. The apparatus may also include an array detector configured to detect a plurality of DLS signals in response to a scattering of the light of the particular wavelength by the mixture, where a particle size distribution of the particle species is determined based on processing the plurality of DLS signals to yield a particle size distribution from a determined plurality of scattered light intensities of the mixture based on the plurality of DLS signals.

[0012] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The foregoing and other features of this disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the

accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the

accompanying drawings, in which:

FIG. 1 includes a conceptual illustration of an example apparatus configured to perform sequential multispectral dynamic light scattering (DLS) for particle size distribution

measurement within a mixture comprising more than one particle species;

FIG. 2 includes a conceptual illustration of an example apparatus configured to perform parallel multispectral DLS for particle size distribution measurement within a mixture comprising more than one particle species;

FIG. 3 A illustrates an example apparatus configured to perform multispectral DLS for particle size distribution measurement within a mixture comprising a single particle species;

FIG. 3B illustrates an example apparatus configured to perform DLS using a line sensor for particle size distribution measurement within a mixture comprising a single particle species; FIG. 4 illustrates major components of an example system configured to perform multispectral DLS to determine particle size distribution measurements;

FIG. 5 illustrates a computing device, which may be used to determine particle size distribution measurements based on results of a performed multispectral DLS;

FIG. 6A and 6B are a flow diagrams illustrating example methods to determine particle size distribution measurements within a mixture based on multispectral DLS results that may be performed by a computing device such as the computing device in FIG. 5; and

FIG. 7A and 7B illustrate block diagrams of example computer program products, some of which are arranged in accordance with at least some embodiments described herein.

DETAILED DESCRIPTION

[0014] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

[0015] This disclosure is generally drawn, inter alia , to methods, apparatus, systems, devices, and/or computer program products related to performance of single or multi-spectral dynamic light scattering (DLS) within a mixture and determination of particle size distribution measurements within the mixture based on results of the performed multispectral DLS.

[0016] Briefly stated, technologies are generally described to determine particle size distribution measurements within a mixture by performing DLS. The mixture may be a solution, a colloid (e.g., an emulsion), or a suspension. The mixture may be comprised of at least one particle species and remaining material, such as other particle species, air bubbles, or other similar materials. In an example scenario, light of a first wavelength and light of a second wavelength may be sequentially or simultaneously directed into the mixture. In response, a first DLS signal that represents a scattering of the light of the first wavelength by the mixture and a second DLS signal that represents a scattering of the light of the second wavelength by the mixture may be detected. The first wavelength may be in a spectral range that the particle species appreciably absorbs light while the remaining material scatters light, whereas the second wavelength may be in a spectral range that both the particle species and the remaining material scatter light.

[0017] A first scattered light intensity of the mixture based on the first DLS signal may be determined to yield a first particle size distribution, and a second scattered light intensity of the mixture based on the second DLS signal may be determined to yield a second particle size distribution. In additional or alternate embodiments, autocorrelation functions (ACFs) of the first and second scattered light intensities of the mixture may be calculated to yield the first and second particle size distributions. The particle size distribution of the particle species may then be determined based on a difference between the first particle size distribution and the second particle size distribution.

[0018] FIG. 1 includes a conceptual illustration of an example apparatus configured to perform sequential multispectral DLS for particle size distribution measurement within a mixture comprising more than one particle species, arranged in accordance with at least some

embodiments described herein.

[0019] As shown in diagram 100, a mixture 102 may be comprised of a first particle species 104 and remaining material, such as a second particle species 106. The mixture 102 may be a solution, a colloid (e.g., an emulsion), or a suspension. To perform sequential multispectral DLS, a first light source 108 may be configured to emit light of a first wavelength at a first time 114 into the mixture 102. The first wavelength may be selected in a spectral range that is appreciably absorbed by the first particle species 104 and scattered by the second particle species 106. The spectral range may be a visible light range, an ultra-violet (UV) light range, an infrared (IR) light range, or a sub-spectral range, among other examples. A detector 112 may be configured to detect a first DLS signal in response to a scattering of the light of the first wavelength by the mixture 102.

[0020] A second light source 110 may be configured to emit light of a second wavelength at a second time 116 into the mixture 102. In other embodiments, the second light source may not be necessary and the first light source 108 may also emit the light of the second wavelength at the second time 116 into the mixture 102. The second wavelength may be selected in another spectral range, distinct from the first wavelength. For example, the second wavelength may be selected in a spectral range that is appreciably scattered by both the first particle species 104 and the second particle species 106. The detector 112 may be configured to detect a second DLS signal in response to a scattering of the light of the second wavelength by the mixture 102.

[0021] In some embodiments, the first light source 108, the second light source 110, and the detector 112 may be integrated into a single, first apparatus configured to perform the multispectral DLS. The first light source 108 and the second light source 110 may be single- wavelength laser sources. For example, the laser sources may be semiconductor laser diodes that may either emit distinctive light beams or may emit light beams that are spatially combined by dichroic beam combiners or a fiber coupler. In other examples, the laser sources may include a dye laser, a gas laser, and/or a solid-state laser, among other similar sources. Alternatively, the first light source 108 and the second light source 110 may be tunable sources, such as optical parametric oscillators or external-cavity diode lasers. The detector 112 may include a photomultiplier tube or semiconductor elements such as an active-pixel sensor (APS), a reverse- biased light emitting diode (LED), a photodiode, a photoresistor, a phototransistor, or a quantum dot photoconductor. The detector may also include a single element detector, an array detector (one or more rows), or a line sensor (multiple elements along a one-dimensional array). The detector may provide continuous or sequential readouts from array sensors such as a charge- coupled device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) device. In the conceptual diagram 100, the positioning and structure of the first light source 108, the second light source 110, and the detector 112 have been simplified for clarity. Configurations of the first apparatus and/or the first light source 108, second light source 110, and detector 112 are not limited to the configurations illustrated in diagram 100. Additionally, in some configurations, the first apparatus may include one or more polarizers. For example, a first polarizer may be positioned between the first and second light sources 108, 110 and the mixture 102 such that the light of the first wavelength and the light of the second wavelength emitted from the first and second light sources 108, 110, respectively, pass through the polarizer prior to reaching the mixture 102. A second polarizer may be positioned between the mixture 102 and the detector 112 such that the light of the first wavelength and the light of the second wavelength scattered by the mixture 102 may be collected for detection by the detector 112. [0022] According to some examples, the detector 112 may be configured to detect a forward scattered light of the first wavelength or the second wavelength and/or a backscattered light of the first wavelength or the second wavelength. The first light source 108 and/or the second light source 110 may be rotated (105) at predetermined increments of angle relative to the mixture directing the light of a first wavelength and/or the light of a second wavelength at various angles into the mixture, and the detector may be in a fixed position relative to the mixture allowing scattered light from different angles to be detected. In some examples, a lens 111 or similar optical element may be used to focus the light from the first light source 108 and/or the second light source 110.

[0023] A second apparatus, coupled to the first apparatus, may be configured to determine a particle size distribution of the first particle species 104 based on results of the multispectral DLS. In some embodiments, the second apparatus may receive the first DLS signal and the second DLS signal from the detector 112. A first scattered light intensity of the mixture may be determined based on the first DLS signal to yield a particle size distribution of the second particle species 106 (i.e., a first particle size distribution). A second scattered light intensity of the mixture may be determined based on the second DLS signal to yield a particle size distribution of an entirety of the mixture 102, which includes both a particle size distribution of the first particle species 104 and the particle size distribution of the second particle species 106, (i.e., a second particle size distribution). The particle size distribution of the first particle species 104 may then be determined based on a difference between the first and second particle size distributions.

[0024] For example, scattered light intensity may be generally and most simplistically defined as:

I(t, l) = Ii(t, ) + h(t, l),

where Ii(t, l) is an intensity of light of a wavelength, L, scattered by the first particle species 104 at time, t, and L(t, l) is an intensity of light of the wavelength, L, scattered by the second particle species 106 at time, t. Although concentrations and diameters of the first particle species 104 and the second particle species 106 in the mixture 102 may also affect the scattered light intensity, as described in paragraph 27 below, the simpler definition will be used to describe the determination of the first and second scattered lights intensities in the following paragraphs. [0025] The first DLS signal may be detected in response to a scattering of the light of a first wavelength, Ai, by the mixture 102. When determining the first scattered light intensity, I(t, Ai), based on the first DLS signal, the intensity of light of the first wavelength scattered by the first particle species 104, Ii(t, Ai), may be substantially smaller than the intensity of light of the first wavelength scattered by the second particle species 106, 1 ₂ (t, Ai),

Ii(t, Ai) « I ₂ (t, Ai),

because the first particle species 104 appreciably absorbs light while the second particle species 106 appreciably scatters light at the first wavelength. Therefore, because the intensity of light of the first wavelength scattered by the first particle species 104, Ii(t, Ai), may be a nominal value, the first scattered light intensity, I(t, Ai), may be approximately equal to the intensity of the light of first wavelength scattered by the second particle species 106, 1 ₂ (t, Ai), in the mixture 102,

I(t, Ai) « I ₂ (t, Ai).

Thus, the first scattered light intensity may yield the particle size distribution of the second particle species 106.

[0026] The second DLS signal may be detected in response to a scattering of the light of a second wavelength, A ₂ , by the mixture 102. When determining the second scattered light intensity, I(t, A ₂ ), based on the second DLS signal, the intensity of light of the second wavelength scattered by the first particle species 104, Ii(t, A ₂ ), may no longer be a nominal value, because the first particle species 104 and the second particle species 106 both appreciably scatter light at the second wavelength. Therefore, the second scattered light intensity, I(t, A ₂ ), may be a summation of the intensities of light scattered by the first particle species 104, Ii(t, A ₂ ), and the second particle species 106, 1 ₂ (t, A ₂ ), (i.e., an entirety of the mixture),

I(t, A ₂ ) = Ii(t, A ₂ ) + I ₂ (t, A ₂ ).

The second scattered light intensity may yield the particle size distribution of the entirety of the mixture, which includes the particle size distribution of the first particle species 104 and the particle size distribution of the second particle species 106.

[0027] In additional or alternate embodiments, autocorrelation functions (ACFs) of the first and second scattered light intensities of the mixture may be calculated to yield the first and second particle size distributions. An ACF typically includes one or more exponential decays, where a decay time may be related to a particle size of the particle species and/or remaining material. For example, in the time domain analysis, the ACF usually decays starting from zero delay time, and faster dynamics due to smaller particle sizes lead to faster decorrelation of scattered light intensity. In the context of the mixture 102, a first ACF of the first scattered light intensity may be calculated, where the first ACF may be dominated by the second particle species 106. Accordingly, analysis of the first ACF may yield the particle size distribution of the second particle species 106 as the first particle size distribution. A second ACF of the second scattered light intensity may then be calculated, where the second ACF may represent the entirety of the mixture. Accordingly, analysis of the second ACF yields the particle size distribution of the entirety of the mixture, which includes particle size distributions of both the first particle species 104 and the second particle species 106, as the second particle size distribution.

[0028] The particle size distribution of the first particle species 104 may then be determined based on the difference between the particle size distribution of the entirety of the mixture 102 (i.e., the particle size distribution of the first particle species 104 and the particle size distribution of the second particle species 106) and the particle size distribution of the second particle species 106.

[0029] To provide an illustrative example, the mixture may include food or coloring agents such as beta-carotene and remaining material comprised of another particle species, such as undissolved sugar particles, and/or air bubbles, in a liquid such as water. Beta-carotene is a natural extract containing carotenoids, including carrot extracts and red palm oil, used for food coloring. Beta-carotene absorbs most strongly at a wavelength between 400 - 500 nanometers (nm), a part of the blue/green spectrum, and thus beta-carotene appears to be orange. The remaining material may be colorless. Therefore, the beta-carotene and the remaining material may have a different response to light at certain wavelengths. Accordingly, multispectral DLS may be performed to determine a particle size distribution of the beta-carotene in the mixture by taking advantage of that differential response to light.

[0030] When performing the multispectral DLS, the first wavelength may be selected at 450 nm at which beta-carotene appreciably absorbs light while the remaining material scatters light, and the second wavelength may be selected at 600 nm at which both beta-carotene and the remaining material appreciably scatter light. The intensity of light of the first wavelength scattered by the beta-carotene may be substantially smaller than the intensity of light of the first wavelength scattered by the remaining material in the mixture. Therefore, the first scattered light intensity may be approximately equal to the intensity of the light of first wavelength scattered by the remaining material, which yields the particle size distribution of the remaining material. In additional or alternate embodiments, a first ACF of the first scattered light intensity may then be calculated, where the first ACF may be dominated by the remaining material and yield the particle size distribution of the remaining material. The second scattered light intensity may be a summation of the intensities of light scattered by the beta-carotene and the remaining material (i.e., an entirety of the mixture), which yields the particle size distribution of the entirety of the mixture. The particle size distribution of the entirety of the mixture may include the particle size distributions of both the beta-carotene and the remaining material. In additional or alternate embodiments, a second ACF of the second scattered light intensity may then be calculated, where the second ACF will represent the entirety of the mixture and yield the particle size distribution of the entirety of the mixture, including the particle size distributions of both the beta-carotene and the remaining material. The particle size distribution of the beta-carotene may then be determined based on the difference between the particle size distribution of the entirety of the mixture (i.e., the particle size distributions of both the beta-carotene and the remaining material) and the particle size distribution of the remaining material.

[0031] Performance of multispectral DLS may also provide additional information on particle size distribution because an intensity of light scattered by particle species is highly non linear dependent on wavelength. To provide an example scenario, the mixture 102 as previously described may be a bi-disperse sample comprised of the first particle species 104 and the second particle species 106. The first particle species 104 may have particles with a first diameter (< d\ ) and may be present in the mixture 102 at a first concentration (pi). The second particle species 106 may have particles with a second diameter (di) and may be present in the mixture 102 at a second concentration (pi). Thus, the intensity of the light of a wavelength (l) scattered by an entirety of the mixture 102 may be generally and more comprehensively defined as (assuming a time parameter is constant):

I(l) = p ₁ /(di,A) + p ₂ l(d ₂ ,X).

[0032] In one example, the particle diameters ch and ch of the first particle species and the second particle species, respectively, may be smaller than about one tenth of the wavelength of the light directed into the mixture 102. Accordingly, the scattering of the light by the mixture 102 occurs in a Rayleigh-regime. In the Rayleigh-regime, an intensity of the scattered light ( IR ) depends on a sixth power of a particle diameter ( _< d) and an inverse of a fourth power of wavelength ( l ):

Thus, rewriting the intensity of the light scattered by the entirety of the mixture 102 in the Rayleigh-regime, yields

which means the intensity of the light scattered by a bi-disperse sample, such as mixture 102, has a same wavelength dependency as a monodisperse sample comprised of only a single particle species. Consequently, by varying the wavelength, we do not gain any additional information about sample distribution, densities, and sizes.

[0033] However, in another example, if at least one of the particle species has a particle diameter that lies in a Mie-regime, the scattering of the light by the mixture 102 occurs in the Mie-regime. Due to non-trivial wavelength dependency, in the Mie-regime, the intensity of the light scattered by the mixture 102 does not simply depend on an inverse of a fourth power of the wavelength like in the Raleigh-regime. For example, for some particle diameters, a slight wavelength increase may cause the intensity of the light scattered by the mixture 102 to increase, whereas in the Rayleigh-regime, the intensity would typically decrease in response to a slight wavelength increase. For example, at a first wavelength (li), if the first particle species 104 has a first particle diameter that is half of the size of the second particle diameter of the second particle species 106, the intensity of the light scattered by the mixture 102 may be dominated by the second particle species 106 because it has the larger particle diameter. However, at a second, lower wave-length (e.g., l ₂ = 0.625 · li), the intensity of the light scattered by the mixture 102 may be dominated by the first particle species 104. Thus, performing multi -wavelength DLS measurement yields additional information about particle size distribution.

[0034] Although DLS is an established technique for measuring particle size distribution, conventional methods for DLS are relatively slow and have low accuracy in resolving the particle size distribution within multi- and single particle species mixtures. For example, in mixtures comprising more than one particle species of varied sizes, derived particle size distribution measurements have low accuracy because the DLS spectrum is often dominated by the larger-sized particle species. In mixtures comprising only a single particle species, derived particle size distribution measurements have low accuracy because the DLS signal detected may be affected by the presence of air bubbles. Thus, embodiments, as described herein, are directed to multispectral DLS to increase the speed and accuracy of particle size distribution

measurements in mixtures comprising one or more particle species.

[0035] FIG. 2 includes a conceptual illustration of an example apparatus configured to perform parallel multispectral DLS for particle size distribution measurement within a mixture comprising more than one particle species, arranged in accordance with at least some embodiments described herein.

[0036] As shown in diagram 200, a mixture 202 may be comprised of a first particle species 204 and remaining material, such as a second particle species 206. The mixture 202 may be a solution, a colloid (e.g., an emulsion), or a suspension. To perform parallel multispectral DLS, a first light source 208 may be configured to emit light of a first wavelength into the mixture 202 at a same time 220 as a second light source 210 is configured to emit light of a second wavelength into the mixture 202. The first wavelength may be selected in a spectral range that is appreciably absorbed by the first particle species 204 and scattered by the second particle species 206. The second wavelength may be selected in another spectral range, distinct from the first wavelength. For example, the second wavelength may be selected in a spectral range that is appreciably scattered by both the first particle species 204 and the second particle species 206. The spectral range from which the first and second wavelength are selected may be a visible light range, a UV light range, an IR light range, or a sub-spectral range, among other examples. In some examples, a lens 211 or similar optical element may be used to focus the light from the first light source 208 and/or the second light source 210.

[0037] The mixture 202 may scatter the light of the first wavelength and the light of the second wavelength. A first spectral filter 212 corresponding to the first wavelength may collect the light of the first wavelength scattered by the mixture 202. A first detector 214 coupled to the first spectral filter 212 may be configured to detect a first DLS signal based on the light collected by the first spectral filter 212. A second spectral filter 216 corresponding to the second wavelength may collect the light of the second wavelength scattered by the mixture 202. A second detector 218 coupled to the second filter 216 may be configured to detect a second DLS signal based on the light collected by the second spectral filter 216. [0038] In some embodiments, the first light source 208, the second light source 210, the first spectral filter 212, the first detector 214, the second spectral filter 216, and the second detector 218 may be integrated into a single, first apparatus configured to perform the multispectral DLS. The types of light sources and detectors employed may be similar to those discussed above in conjunction with FIG. 1. In the conceptual diagram 200, the positioning and structure of the first light source 208, the second light source 210, the first spectral filter 212, the first detector 214, the second spectral filter 216, and the second detector 218 have been simplified for clarity. Configurations of the first apparatus and/or the first light source 208, the second light source 210, the first spectral filter 212, the first detector 214, the second spectral filter 216, and the second detector 218 are not limited to the configurations illustrated in diagram 200. Additionally, the first apparatus may include one or more polarizers. For example, a first polarizer may be positioned between the first and second light sources 208, 210 and the mixture 102 such that the light of the first wavelength and the light of the second wavelength emitted from the first and second lights sources 208, 210, respectively, pass through the polarizer prior to reaching the mixture 202. A second polarizer may be positioned between the mixture 102 and the first and second detectors 214, 218 such that the light of the first wavelength and the light of the second wavelength scattered by the mixture 202 may be collected for detection by the first and second detectors 214, 218.

[0039] According to some examples, the second detector 218 (and second filter 216) may be positioned in an opposite direction of the first detector 214 (and first filter 212) such that the first detector 214 and the second detector 217 may detect forward scattered and/or backscattered light of the first wavelength or the second wavelength. As discussed above in conjunction with FIG. 1, the first light source 208, the second light source 210, the first detector 214, or the second detector 218 may be rotated at predetermined increments of angle relative to the mixture such that scattered light from different angles may be detected.

[0040] A second apparatus, coupled to the first apparatus, may be configured to determine a particle size distribution of the first particle species 204 based on results of the multispectral DLS. In some embodiments, the second apparatus may receive the first DLS signal and the second DLS signal from the first detector 214 and the second detector 218, respectively. A first scattered light intensity of the mixture may be determined based on the first DLS signal to yield a particle size distribution of the second particle species 206 (i.e., a first particle size distribution). A second scattered light intensity of the mixture may be determined based on the second DLS signal to yield a particle size distribution of an entirety of the mixture 202, which includes both a particle size distribution of the first particle species 204 and the particle size distribution of the second particle species 206 (i.e., a second particle size distribution). The particle size distribution of the first particle species 204 may then be determined based on a difference between the first and second particle size distributions.

[0041] For example, scattered light intensity may be generally and most simplistically defined as:

I(t, A) Ii(t, A) + L(t, A),

where Ii(t, A) is an intensity of light of a wavelength, A, scattered by the first particle species 204 at time, t, and l2(t, A) is an intensity of light of the wavelength, A, scattered by the second particle species 206 at time, t. Although concentrations and diameters of the first particle species 204 and the second particle species 206 in the mixture 202 may also affect the scattered light intensity, this simplified definition will be used to describe the determination of the first and second scattered lights intensities in the following paragraphs.

[0042] The first DLS signal may be detected in response to a scattering of the light of a first wavelength, Ai, by the mixture 202. When determining the first scattered light intensity, I(t, Ai), based on the first DLS signal, the intensity of light of the first wavelength scattered by the first particle species 204, Ii(t, Ai), may be substantially smaller than the intensity of light of the first wavelength scattered by the second particle species 206, L(t, Ai),

Ii(t, Ai) « L(t, Ai),

because the first particle species 204 appreciably absorbs light while the second particle species 106 appreciably scatters light at the first wavelength. Therefore, because the intensity of light of the first wavelength scattered by the first particle species 204, Ii(t, Ai), may be a nominal value, the first scattered light intensity, I(t, Ai), may be approximately equal to the intensity of the light of first wavelength scattered by the second particle species 206, L(t, Ai), in the mixture 202,

I(t, Ai) « L(t, Ai).

Thus, the first scattered light intensity may yield the particle size distribution of the second particle species 206. In additional or alternate embodiments, a first ACF of the first scattered light intensity may then be calculated, where the first ACF may be dominated by the second particle species 206. Accordingly, analysis of the first ACF may yield the particle size distribution of the second particle species 206.

[0043] The second DLS signal may be detected in response to a scattering of the light of a second wavelength, l ₂ , by the mixture 202. When determining the second scattered light intensity, I(t, l ₂ ), based on the second DLS signal, the intensity of light of the second wavelength scattered by the first particle species 204, Ii(t, l ₂ ), may no longer be a nominal value, because the first particle species 204 and the second particle species 206 both appreciably scatter light at the second wavelength. Therefore, the second scattered light intensity, I(t, l ₂ ), may be a summation of the intensities of light scattered by the first particle species 204, Ii(t, l ₂ ) and the second particle species 206, 1 ₂ (t, l ₂ ), (i.e., an entirety of the mixture),

I(t, A ₂ ) = Ii(t, A ₂ ) + b(t, A ₂ ).

[0044] The second scattered light intensity may yield the particle size distribution of the entirety of the mixture, which includes the particle size distributions of both the first particle species 204 and the second particle species 206. In additional or alternate embodiments, a second ACF of the second scattered light intensity may then be calculated, where the second ACF may represent the entirety of the mixture. Accordingly, analysis of the second ACF yields the particle size distribution of the entirety of the mixture, which includes particle size distributions of both the first particle species 204 and the second particle species 206.

[0045] The particle size distribution of the first particle species 204 may then be determined based on the difference between the particle size distribution of the entirety of the mixture 102 (i.e., the particle size distribution of the first particle species 204 and the particle size distribution of the second particle species 206) and the particle size distribution of the second particle species 206.

[0046] FIG. 3 A illustrates an example apparatus configured to perform multispectral DLS for particle size distribution measurement within a mixture comprising a single particle species, arranged in accordance with at least some embodiments described herein.

[0047] In some examples, air bubbles or carbon dioxide bubbles in a liquid mixture (e.g., a solution or a carbonated beverage) may have an impact on a scattered light intensity of the mixture. For example, such bubbles typically undergo Brownian motion and their influence is not static. The effect of carbon dioxide bubbles may be reduced by forcing them to dissolve in the liquid through temperature and/or pressure modifications, however, the effect of air bubbles may not be as easily reduced, especially when the air bubbles are large in diameter.

[0048] As shown in diagram 300A, a mixture 302 may be comprised of a particle species 304 and remaining material, such as air bubbles 306, in a host liquid. As illustrated, the air bubbles 306 may be larger in diameter than the particles species 304. Multispectral DLS may be performed sequentially as described in FIG. 1 or in parallel as described in FIG. 2, where the multispectral DLS may separate light scattering contributions from the particle species 304 and the air bubbles 306 in order to more accurately determine a particle size distribution of the particle species 304. For example, light of a first wavelength may be emitted by a first light source 308 into the mixture 302 followed by or simultaneously with (dependent on whether the multispectral DLS is performed sequentially or in parallel, respectively) light of a second wavelength emitted by a second light source 310 into the mixture 302. The first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species 304 and scattered by the air bubbles 306. The second wavelength may be selected in another spectral range that is appreciably scattered by both the particle species 304 and the second air bubbles 306. The spectral range of the first and second wavelengths may be a visible light range, a UV light range, an IR light range, or a sub-spectral range, among other examples. In some examples, a lens 311 or similar optical element may be used to focus the light from the first light source 308 and/or the second light source 310.

[0049] One or more detectors 312 may be configured to detect a first DLS signal in response to a scattering of the light of the first wavelength by the mixture 302 and a second DLS signal in response to a scattering of the light of the second wavelength by the mixture 302. If sequential multispectral DLS is performed, a single detector may be configured to detect the first and second DLS signal. If parallel multispectral DLS is performed, a first detector and a second detector may be configured to detect the first and second DLS signal, respectively. The first detector may be coupled to a first spectral filter corresponding to the first wavelength that collects the light of the first wavelength scattered by the mixture 302. The second detector may be coupled to a second spectral filter corresponding to the second wavelength that collects the light of the second wavelength scattered by the mixture 302. The types and configurations of lights sources, detector(s), and/or spectral filters employed may be similar to those discussed in conjunction with FIGS. 1 and 2. In some embodiments, the lights sources, detector(s) and/or spectral filters may be integrated within a single, first apparatus.

[0050] A particle size distribution of the particle species 304 may then be determined based on results of the multispectral DLS (i.e., the first and second DLS signals). In some

embodiments, a second apparatus communicatively coupled to the first apparatus or at least the detector(s) may be configured to determine the particle size distribution of the particle species 304.

[0051] A first scattered light intensity of the mixture may be determined based on the first DLS signal to yield a particle size distribution of the air bubbles 306 as a first particle size distribution. Because the particle species 304 appreciably absorbs light while the air bubbles 306 appreciably scatter light at the first wavelength, the intensity of light of the first wavelength scattered by the particle species 304 may be substantially smaller than the intensity of light of the first wavelength scattered by the air bubbles 306. Therefore, because the intensity of light of the first wavelength scattered by the particle species 304 may be a nominal value, the first scattered light intensity may be approximately equal to the intensity of the light of first wavelength scattered by the air bubbles 306. Accordingly, the first scattered light intensity may yield the particle size distribution of the air bubbles 306 as the first particle size distribution. In additional or alternate embodiments, a first ACF of the first scattered light intensity may then be calculated, where the first ACF may be dominated by the air bubbles 306. Accordingly, analysis of the first ACF may yield the particle size distribution of the air bubbles 306 as the first particle size distribution.

[0052] A second scattered light intensity of the mixture may be determined based on the second DLS signal to yield a particle size distribution of the entirety of the mixture 302 as a second particle size distribution. Because the particle species 304 and the air bubbles 306 both appreciably scatter light at the second wavelength, the intensity of light of the second wavelength scattered by the particle species 304 may no longer be a nominal value. Therefore, the second scattered light intensity may be a summation of the intensities of light scattered by the particle species 304 and the air bubbles 306 (i.e., a total intensity of light scattered by an entirety of the mixture), which yields the particle size distribution of the entirety of the mixture as the second particle size distribution. The particle size distribution of the entirety of the mixture may include the particle size distribution of the particle species 304 and the particle size distribution of the air bubbles 306. In additional or alternate embodiments, a second ACF of the second scattered light intensity may then be calculated, where the second ACF may represent the entirety of the mixture 302. Accordingly, analysis of the second ACF may yield the particle size distribution of the entirety of the mixture 302, which includes the particle size distribution of the particle species 304 and the particle size distribution of the air bubbles 306, as the second particle size distribution.

[0053] The particle size distribution of the particle species 304 may then be determined based on the difference between first and second particle size distributions. Therefore, the particle size distribution of the particle species 304 may be determined by subtracting the particle size distribution of the air bubbles 306 from the particle size distribution of the entirety of the mixture 302 (i.e., the particle size distribution of the particle species 304 and the particle size distribution of the air bubbles 306).

[0054] FIG. 3B illustrates an example apparatus configured to perform DLS using a line sensor for particle size distribution measurement within a mixture comprising a single particle species, arranged in accordance with at least some embodiments described herein.

[0055] As shown in diagram 300B, a mixture 312 may be comprised of a first particle species 314 and a second particle species 316, in a host liquid. As illustrated, the second particle species 316 may be larger in diameter than the first particles species 314. Multispectral DLS may be performed sequentially as described in FIG. 1 or in parallel as described in FIG. 2, where the multispectral DLS may separate light scattering contributions from the first particle species 314 and the second particle species 316 in order to more accurately determine a particle size distribution of the first particle species 314 and/or the second particle species 316.

[0056] Differently from above-described examples, the system (or apparatus) in diagram 300B may include an array detector 322, for example, a line sensor. A line sensor is a special case of an image sensor. The pixels in a line sensor are arranged along a single line. Like other image sensors, a line sensor works periodically: pre-defmed exposure is followed by readout, and the pixels are reset. One example line sensor implementation may deliver 100 ksamples/s at 8192 pixels, allowing for detection of frequencies up to 50 kHz. Increasing the sampling rate, when needed, may be possible with windowing (selecting of pixel subset) or pixel binning. The scattered light 326 from first particle species 314 or the second particle species 316 may be directed by a lens 324 or similar optical device as parallelized light 328 to be collected on the pixels of the array detector 322 (line sensor) resulting in multiple time-dependent signals, acquired simultaneously. Each signal may be processed independently and deliver particle size distribution with accuracy dependent on a pre-defmed acquisition time. Processing may include integration, addition, averaging, subtraction, dynamic filtering, and comparable operations performed on the collected individual signals. Assuming the measurements are independent, affected by statistical noise only, the measurement accuracy of the system may improve by a factor of square-root of N, where N is the number of channels (pixels). Because the array detector configuration involves multiple simultaneous measurements, accurate results may be obtained using a single wavelength (first light source 308). However, using at least two light sources (e.g., optional second light source 310) with different wavelengths, different size particles may be detected or effects of some particles or bubbles in the liquid may be filtered out. Thus, in an example system, employing first light source 308 may provide a square-root of N improvement over single wavelength, single detector DLS. The addition of the second light source 310 (using two array detectors or sequential measurement) may further improve system accuracy by square-root of 2. As in the other examples discussed above, the array detector may be positioned (relative to the mixture and the light source(s)) allowing backscattered light or forward scattered light to be captured. Other angles such as 90° may also be used.

[0057] In an experimental example measurement implementation conducted for

polystyrene microspheres (refraction index n = 1.59) and for vegetable oil droplets (n = 1.47) suspended in water (n = 1.33) contained in a spectroscopic cuvette, the spherical particle diameters may be selected to cover the range of interest and to correlate with available calibrated microspheres such as 100 nm, 300 nm, 1 pm, 3 pm and 5 pm. Example wavelengths may be selected as discrete diode laser wavelengths of 405 nm (violet), 532 nm (green) and 690 nm (red) (unpolarized). Results of the example measurements indicate that scattering efficiency grows with particle size, scattering is more efficient in forward direction, especially for bigger particles, and high-frequency scattering angle dependence is present for bigger particles, both size and wavelength dependent. Scattering angle dependence may be used for particle size extraction. DLS measurement may be conducted at forward scattering direction (small angle) and at backscattering (scattering angle close to 180°), or optionally at right angle. High-frequency angle dependent scattering features may be used for particle size distributions containing few monodisperse sizes. [0058] As discussed above, repeating the measurement N-times (N pixels) and averaging the result may reduce uncertainty approximately by l/VN (improve accuracy by A/N). With a single detector, accuracy improvement may be achieved at the expense of increased

measurement time. Conducting simultaneous measurements with N detectors may improve accuracy or reduces measurement time. Thus, a trade-off may be made between number of pixels in a line sensor and desired measurement speed. Simultaneous measurement on two channels (two detectors) such as using two wavelengths may provide 1/V2 reduction in uncertainty (V2 improvement in accuracy).

[0059] Scattering efficiency dependence on scattering angle is found to be substantially distinctive for particles larger than wavelength. These oscillations may be utilized for particle size measurement. Beyond high frequency oscillations, a general difference in scattering angle distribution between small and large particles may also be observed. Particles substantially smaller than wavelength may scatter uniformly in all directions, while scattering on particles comparable in size (or larger) to the wavelength is dominated by forward scattering. The forward scattering intensity may be superior over backscattering by three or four orders of magnitude. This effect may be utilized as an aid for indication or extraction of multiple scattering effects.

[0060] FIG. 4 illustrates major components of an example system configured to perform multispectral DLS to determine particle size distribution measurements, arranged in accordance with at least some embodiments described herein.

[0061] System 400 may include a system controller 420, a first apparatus 422, and a second apparatus 424. The system controller 420 may be operated by human control or may be configured for automatic operation or may be directed by a remote controller 440 through at least one network (for example, via network 410). Data associated with controlling the different processes of multispectral DLS performance and determination of particle size distribution measurements based on results of the performed multispectral DLS may be stored at and/or received from data stores 460.

[0062] The system controller 420 may include or control the first apparatus 422, where the first apparatus 422 may include one or more light sources 426, one or more detectors 428, and optional spectral filters 430. If sequential multispectral DLS is performed, the first apparatus 422 may include one or more light sources 426 and a detector 428. If parallel multispectral DLS is performed, the first apparatus 422 may include one or more light sources 426, one or more detectors 428, and at least two spectral filters 430 that are coupled to the detectors 428 and correspond to a particular wavelength emitted by the lights sources 426.

[0063] For example, light of a first wavelength may be emitted by one of the light sources 426 into a mixture followed by or simultaneously with (dependent on sequential or parallel multispectral DLS, respectively) light of a second wavelength emitted by the same light source or another one of the light sources 426 into the mixture. The mixture may include at least one particle species and remaining material, where the remaining material may include other particle species, air bubbles, or other similar material. The first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species and scattered by the remaining material. The second wavelength may be selected in another spectral range that is scattered by both the particle species and the remaining material. The detectors 428 may be configured to detect a first DLS signal in response to a scattering of the light of the first wavelength by the mixture and a second DLS signal in response to a scattering of the light of the second wavelength by the mixture.

[0064] The system controller 420 may also include or control the second apparatus 424, where the second apparatus 424 may include a communication interface configured to facilitate communication between the second apparatus 424 and the first apparatus 422, a memory configured to store instructions, and a processor coupled to the communication interface and the memory. The processor may be configured to receive, through the communication interface, the first DLS signal and the second DLS signal from the first apparatus 422. The processor may then be configured to determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0065] The first apparatus 422 and the second apparatus 424 may be software, hardware, firmware, or virtually any combination thereof. In one embodiment, the modules may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats, for example.

[0066] The examples provided in FIGs. 1 through 4 are illustrated with specific systems, apparatuses, configurations, and scenarios. Embodiments are not limited to environments according to these examples. Determination of particle size distribution measurements based on multispectral DLS results may be implemented in environments employing fewer or additional systems, apparatuses, configurations and scenarios. Furthermore, the example systems, apparatuses, and scenarios shown in FIGs. 1 through 4 may be implemented in a similar manner with other user interface or action flow sequences using the principles described herein.

[0067] FIG. 5 illustrates a computing device, which may be used to determine particle size distribution measurements based on results of a performed multispectral DLS, arranged in accordance with at least some embodiments described herein.

[0068] For example, the computing device 500 may be used to determine particle size distribution measurements based on results of a performed multispectral DLS. In an example basic configuration 502, the computing device 500 may include one or more processors 504 and a system memory 506. A memory bus 508 may be used to communicate between the processor 504 and the system memory 506. The basic configuration 502 is illustrated in FIG. 5 by those components within the inner dashed line.

[0069] Depending on the desired configuration, the processor 504 may be of any type, including but not limited to a microprocessor (mR), a microcontroller (pC), a digital signal processor (DSP), or any combination thereof. The processor 504 may include one or more levels of caching, such as a cache memory 512, a processor core 514, and registers 516. The example processor core 514 may include an arithmetic logic unit (ALU), a floating point unit (FPU), a digital signal processing core (DSP Core), or any combination thereof. An example memory controller 518 may also be used with the processor 504, or in some implementations, the memory controller 518 may be an internal part of the processor 504.

[0070] Depending on the desired configuration, the system memory 506 may be of any type including but not limited to volatile memory (such as RAM), non-volatile memory (such as ROM, flash memory, etc.) or any combination thereof. The system memory 506 may include an operating system 520, a controller 522, and program data 524. The controller 522 may be configured to receive a first DLS signal and a second DLS signal, where the first DLS signal and the second DLS signal are detected in response to a scattering of a light of a first wavelength and a light of a second wavelength by the mixture following a direction of the light of the first wavelength and the light of the second wavelength into the mixture, respectively. The controller 522 may include a computation component 526 configured to determine the particle size distribution of the particle species based on results of the multispectral DLS (i.e., the first and second DLS signals). For example, the computation component 526 may be configured to determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution. The program data 524 may include, among other data, process data 528 such as the DLS results, the scattered light intensity measurements, and the particle size distribution measurements, as described herein.

[0071] The computing device 500 may have additional features or functionality, and additional interfaces to facilitate communications between the basic configuration 502 and any desired devices and interfaces. For example, a bus/interface controller 530 may be used to facilitate communications between the basic configuration 502 and one or more data storage devices 532 via a storage interface bus 534. The data storage devices 532 may be one or more removable storage devices 536, one or more non-removable storage devices 538, or a combination thereof. Examples of the removable storage and the non-removable storage devices include magnetic disk devices such as flexible disk drives and hard-disk drives (HDDs), optical disk drives such as compact disc (CD) drives or digital versatile disk (DVD) drives, solid state drives (SSDs), and tape drives to name a few. Example computer storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.

[0072] The system memory 506, the removable storage devices 536 and the non-removable storage devices 538 are examples of computer storage media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD- ROM, digital versatile disks (DVDs), solid state drives (SSDs), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information and which may be accessed by the computing device 500. Any such computer storage media may be part of the computing device 500. [0073] The computing device 500 may also include an interface bus 540 for facilitating communication from various interface devices (e.g., one or more output devices 542, one or more peripheral interfaces 550, and one or more communication devices 560) to the basic configuration 502 via the bus/interface controller 530. Some of the example output devices 542 include a graphics processing unit 544 and an audio processing unit 546, which may be configured to communicate to various external devices such as a display or speakers via one or more A/V ports 548. One or more example peripheral interfaces 550 may include a serial interface controller 554 or a parallel interface controller 556, which may be configured to communicate with external devices such as input devices (e.g., keyboard, mouse, pen, voice input device, touch input device, etc.) or other peripheral devices (e.g., printer, scanner, etc.) via one or more I/O ports 558. An example communication device 560 includes a network controller 562, which may be arranged to facilitate communications with one or more other computing devices 566 over a network communication link via one or more communication ports 564. The one or more other computing devices 566 may include servers at a datacenter, customer equipment, and comparable devices.

[0074] The network communication link may be one example of a communication media. Communication media may be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and may include any information delivery media. A“modulated data signal” may be a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), microwave, infrared (IR) and other wireless media. The term computer readable media as used herein may include both storage media and communication media.

[0075] The computing device 500 may be implemented as a part of a general purpose or specialized server, mainframe, or similar computer that includes any of the above functions. The computing device 500 may also be implemented as a personal computer including both laptop computer and non-laptop computer configurations.

[0076] FIG. 6A and 6B are flow diagrams illustrating example methods to determine particle size distribution measurements within a mixture based on multispectral DLS results that may be performed by a computing device such as the computing device in FIG. 5, arranged in accordance with at least some embodiments described herein.

[0077] Example methods may include one or more operations, functions or actions as illustrated by one or more of blocks 622, 624, 626, and/or 628, and 632, 634, and/or 636, which may in some embodiments be performed by a computing device such as the computing device 610 in FIG. 6. The operations described in the blocks 622-628 and 632-636 may also be stored as computer-executable instructions in a computer-readable medium such as a computer-readable medium 620 of the computing device 610.

[0078] An example process to determine particle size distribution measurements within a mixture based on multispectral DLS results, as shown in FIG. 6A, may begin with block 622, “RECEIVE A FIRST DLS SIGNAL AND A SECOND DLS SIGNAL, WHERE THE FIRST DLS SIGNAL AND THE SECOND DLS SIGNAL ARE DETECTED IN RESPONSE TO A SCATTERING OF A LIGHT OF A FIRST WAVELENGTH AND A LIGHT OF A SECOND WAVELENGTH BY A MIXTURE FOLLOWING A DIRECTION OF THE LIGHT OF THE FIRST WAVELENGTH AND THE LIGHT OF THE SECOND WAVELENGTH INTO THE MIXTURE, RESPECTIVELY”, where the mixture may be comprised of a particle species and remaining material, such as one or more other particle species, air bubbles, or other similar material. The first wavelength may have been selected in a spectral range that is appreciably absorbed by the particle species and scattered by the remaining material. The second wavelength may have been selected in another spectral range that is appreciably scattered by both the particle species and the remaining material.

[0079] Block 622 may be followed by block 624,“DETERMINE A FIRST SCATTERED LIGHT INTENSITY OF THE MIXTURE BASED ON THE FIRST DLS SIGNAL TO YIELD A FIRST PARTICLE SIZE DISTRIBUTION”, where, because the particle species appreciably absorbs light while the remaining material scatters light at the first wavelength, the intensity of light of the first wavelength scattered by the particle species may be substantially smaller than the intensity of light of the first wavelength scattered by the remaining material. Therefore, the first scattered light intensity may be approximately equal to the intensity of the light of first wavelength scattered by the remaining material, which yields the particle size distribution of the remaining material as the first particle size distribution. In additional or alternate embodiments, a first ACF of the first scattered light intensity may then be calculated, where the first ACF may be dominated by the remaining material. Accordingly, analysis of the first ACF may also yield the particle size distribution of the remaining material as the first particle size distribution.

[0080] Block 624 may be followed by block 626,“DETERMINE A SECOND

SCATTERED LIGHT INTENSITY OF THE MIXTURE BASED ON THE SECOND DLS SIGNAL TO YIELD A SECOND PARTICLE SIZE DISTRIBUTION”, where, because the particle species and the remaining material both appreciably scatter light at the second wavelength, the second scattered light intensity may be a summation of the intensities of light scattered by the particle species the remaining material (i.e., a total intensity of light scattered by an entirety of the mixture). The second scattered light intensity may yield the particle size distribution of the entirety of the mixture as the second particle size distribution, where the particle size distribution of the entirety of the mixture includes both a particle size distribution of the particle species and the particle size distribution of the remaining material. In additional or alternate embodiments, a second ACF of the second scattered light intensity may then be calculated, where the second ACF will represent the entirety of the mixture. Accordingly, analysis of the second ACF yields the particle size distribution of the entirety of the mixture, including the particle size distributions of both the particle species and the remaining material, as the second particle size distribution.

[0081] Block 626 may be followed by block 628,“DETERMINE THE PARTICLE SIZE DISTRIBUTION OF THE PARTICLE SPECIES BASED ON A DIFFERENCE BETWEEN THE FIRST PARTICLE SIZE DISTRIBUTION AND THE SECOND PARTICLE SIZE DISTRIBUTION”, where, because the second particle size distribution is the particle size distribution of the entirety of the mixture (i.e., the particle size distributions of both the particle species and the remaining material) and the first particle size distribution is the particle size distribution of the remaining material, the particle size distribution of the particle species may be determined by subtracting the first particle size distribution from the second particle size distribution.

[0082] Another example process to determine particle size distribution measurements within a mixture based on multispectral DLS results using a line sensor, as shown in FIG. 6B, may begin with block 632,“RECEIVE A FIRST AND A SECOND PLURALITY OF DLS SIGNALS, WHERE THE FIRST AND THE SECOND PLURALITY OF DLS SIGNALS ARE DETECTED AT A LINE SENSOR IN RESPONSE TO A SCATTERING OF LIGHT OF A FIRST WAVELENGTH AND LIGHT OF A SECOND WAVELENGTH BY A MIXTURE FOLLOWING A DIRECTION OF THE LIGHT OF THE FIRST WAVELENGTH AND THE LIGHT OF THE SECOND WAVELENGTH INTO THE MIXTURE”, where the mixture may be comprised of a particle species and remaining material, such as one or more other particle species, air bubbles, or other similar material. The first wavelength may have been selected in a spectral range that is appreciably absorbed by the particle species and scattered by the remaining material. The second wavelength may be selected in a different spectral region, for example, one that is appreciably absorbed by the remaining material. The detection may be at pixels of a line sensor resulting in multiple, simultaneous time-dependent measurements.

[0083] Block 632 may be followed by block 634,“DETERMINE A FIRST PLURALITY OF SCATTERED LIGHT INTENSITIES AND A SECOND PLURALITY OF SCATTERED LIGHT INTENSITIES OF THE MIXTURE BASED ON THE RESPECTIVE FIRST AND SECOND PLURALITY OF DLS SIGNALS TO YIELD A FIRST PARTICLE SIZE DISTRIBUTION AND A SECOND PARTICLE SIZE DISTRIBUTION”, where, light intensities for the particle species in the mixture may be determined based on the detected scattered light by each pixel of the line sensor to yield the particle size distribution for the mixture.

[0084] Block 634 may be followed by block 636,“DETERMINE THE PARTICLE SIZE DISTRIBUTION OF THE PARTICLE SPECIES BASED ON PROCESSING THE FIRST PARTICLE SIZE DISTRIBUTION AND THE SECOND PARTICLE SIZE DISTRIBUTION”, where, through processing such as integration, addition, averaging, subtraction, or using an auto- correlation function (ACF) of the determined scattered light intensities (of each wavelength) by each pixel of the line sensor, particle size distribution for the particle species of interest may be determined.

[0085] The operations included in the processes of FIG. 6 A and 6B are for illustration purposes. Particle size distribution measurements within a mixture based on multispectral DLS or line sensor measurements may be implemented by similar processes with fewer or additional operations, as well as in different order of operations using the principles described herein. The operations described herein may be executed by one or more processors operated on one or more computing devices, one or more processor cores, and/or specialized processing devices, among other examples [0086] FIG. 7 A and 7B illustrate block diagrams of example computer program products, arranged in accordance with at least some embodiments described herein, arranged in accordance with at least some embodiments described herein.

[0087] In some examples, as shown in FIG. 7A and 7B, a computer program product 700 may include a signal bearing medium 702 that may also include one or more machine readable instructions 704 that, when executed by, for example, a processor may provide the functionality described herein. Thus, for example, referring to the processor 504 in FIG. 5, the controller 522 may undertake one or more of the tasks shown in FIG. 7A and 7B in response to the instructions 704 conveyed to the processor 504 by the signal bearing medium 702 to perform actions associated with determining particle size distributions as described herein. Some of those instructions may include, for example in FIG. 7A, instructions to receive a first DLS signal and a second DLS signal, where the first DLS signal and the second DLS signal are detected in response to a scattering of a light of a first wavelength and a light of a second wavelength by a mixture following a direction of the light of the first wavelength and the light of the second wavelength into the mixture, respectively; determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution; determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution; and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution, according to some embodiments described herein. The instructions may also include, for example in FIG. 7B, instructions to receive a first and a second plurality of DLS signals, where the first and the second plurality of DLS signals are detected at a line sensor in response to a scattering of light of a first wavelength and light of a second wavelength by a mixture following a direction of the light of the first wavelength and the light of the second wavelength into the mixture; determine a first plurality of scattered light intensities and a second plurality of scattered light intensities of the mixture based on the respective first and second plurality of DLS signals to yield a first particle size distribution and a second particle size distribution; and/or determine the particle size distribution of the particle species based on processing the first particle size distribution and the second particle size distribution, according to other

embodiments described herein. [0088] In some implementations, the signal bearing medium 702 depicted in FIG. 7A and 7B may encompass computer-readable medium 706, such as, but not limited to, a hard disk drive (HDD), a solid state drive (SSD), a compact disc (CD), a digital versatile disk (DVD), a digital tape, memory, etc. In some implementations, the signal bearing medium 702 may encompass recordable medium 708, such as, but not limited to, memory, read/write (R/W) CDs, R/W DVDs, etc. In some implementations, the signal bearing medium 702 may encompass communications medium 710, such as, but not limited to, a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.). Thus, for example, the computer program product 700 may be conveyed to one or more modules of the processor 504 by an RF signal bearing medium, where the signal bearing medium 702 is conveyed by the communications medium 710 (e.g., a wireless communications medium conforming with the IEEE 802.11 standard).

[0089] According to some embodiments, means to perform multispectral DLS for particle size distribution measurement are provided. Example means may include performing, by a first apparatus, the multispectral DLS within a mixture that comprises a particle species by directing light of a first wavelength into the mixture, where the first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species, directing light of a second wavelength into the mixture, where the second wavelength may be selected in another spectral range distinct from the first spectral range, and detecting, through a detector, a first DLS signal in response to a scattering of the light of the first wavelength by the mixture and a second DLS signal in response to a scattering of the light of the second wavelength by the mixture. The example means may also include determining, by a processor communicatively coupled to the first apparatus, a particle size distribution of the particle species based on results of the multispectral DLS by receiving the first DLS signal and the second DLS signal from the detector, determining a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determining a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determining the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0090] According to some examples, methods to perform multispectral DLS for particle size distribution measurement are provided. An example method may include performing, by a first apparatus, the multispectral DLS within a mixture that comprises a particle species by directing light of a first wavelength into the mixture, where the first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species, directing light of a second wavelength into the mixture, where the second wavelength may be selected in another spectral range distinct from the first spectral range, and detecting, through a detector, a first DLS signal in response to a scattering of the light of the first wavelength by the mixture and a second DLS signal in response to a scattering of the light of the second wavelength by the mixture. The example method may also include determining, by a processor communicatively coupled to the first apparatus, a particle size distribution of the particle species based on results of the multispectral DLS by receiving the first DLS signal and the second DLS signal from the detector, determining a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determining a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determining the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[0091] In other examples, the multispectral DLS may be performed sequentially or parallel. If the multispectral DLS is performed sequentially, the light of the first wavelength may be initially directed into the mixture and the light of the second wavelength may be subsequently directed into the mixture. If the multispectral DLS is performed parallel, the light of the first wavelength and the light of the second wavelength may be simultaneously directed into the mixture. A first spectral filter and a first detector corresponding to the first wavelength may be employed to collect and detect the light of the first wavelength scattered by the mixture, and a second spectral filter and a second detector corresponding to the second wavelength may be employed to collect and detect the light of the second wavelength scattered by the mixture. The mixture may comprise the particle species and remaining material, and the remaining material may comprise one or more other particles or air bubbles. The first spectral range may include wavelengths that are appreciably absorbed by the particle species. The detector may be a line sensor and the method may also include employing a lens to project one or more of the scattered light of the first wavelength or the scattered light of the second wavelength by the mixture onto the line sensor. The method may further include detecting one or more of a forward scattered light of the first wavelength, a forward scattered light of the second wavelength, a backscattered light of the first wavelength, or a backscattered light of the second wavelength. The method may also include directing one or more of the light of a first wavelength or the light of a second wavelength at predetermined increments of angle into the mixture, wherein the detector is in a fixed position relative to the mixture.

[0092] In further examples, a first autocorrelation function (ACF) of the determined first scattered light intensity may be computed to yield the first particle size distribution, and a second ACF of the determined second scattered light intensity may be computed to yield the second particle size distribution. In response to the direction of the light of the first wavelength into the mixture, the particle species may scatter a substantially lesser amount of the light of the first wavelength than remaining material in the mixture. An intensity of the light of the first wavelength scattered by the remaining material in the mixture may be determined to yield the first particle size distribution, and/or a first ACF of the determined intensity of the light of the first wavelength scattered by the remaining material in the mixture may be computed to yield the first particle size distribution. The particle size distribution may be a particle size distribution of the remaining material in the mixture.

[0093] In some examples, the second wavelength may be selected in the other spectral range that is appreciably scattered by the particle species and remaining material in the mixture such that, in response to the direction of the light of the first wavelength into the mixture, an entirety of the mixture scatters the light of the second wavelength. An intensity of light of the second wavelength scattered by the entirety of the mixture may be determined to yield the second first particle size distribution, and/or a second ACF of the determined intensity of light of the second wavelength scattered by the entirety of the mixture may be computed to yield the second particle size distribution. The second particle size distribution may be a particle size distribution of the entirety of the mixture comprised of the particle size distribution of the particle species and a particle size distribution of the remaining material in the mixture.

[0094] In other examples, the mixture may be a solution, a colloid, and/or a suspension.

The particle species may be a flavoring agent and/or a coloring agent. If the particle species is beta-carotene, the first wavelength may be selected in a range of about 400 to 500 nanometers (nm), and the second wavelength may be selected in a range of about 600 to 700 nm. At least one light source may be configured to emit the light of the first wavelength and the light of the second wavelength that are directed into the mixture. [0095] According to some embodiments, apparatuses to perform sequential multispectral DLS within a mixture that comprises a particle species are described. An example apparatus may include a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species, and a second light source configured to sequentially emit light of a second wavelength into the mixture, where the second wavelength may be selected in another spectral range distinct from the first spectral range. The example apparatus may also include a detector configured to detect a first DLS signal corresponding to a scattering of the light of the first wavelength by the mixture and a second DLS signal corresponding to a scattering of the light of the second wavelength by the mixture, where a particle size distribution of the particle species may be determined based on a difference between a first particle size distribution yielded from a determined first scattered light intensity of the mixture based on the first DLS signal and a second particle size distribution yielded by a determined second scattered light intensity of the mixture based on the second DLS signal.

[0096] In other embodiments, the spectral range and the other spectral range may be comprised of a visible light range, a UV light range, an IR light range, and/or a sub-spectral range. The first wavelength may be selected in the spectral range that is appreciably absorbed by the particle species such that, in response to the emission of the light of the first wavelength into the mixture, the particle species scatters a substantially lesser amount of the light of the first wavelength than remaining material in the mixture. The determined first scattered light intensity of the mixture based on the first DLS signal may be an intensity of the light of the first wavelength scattered by the remaining material, and the first particle size distribution may be yielded from the determined first scattered light intensity and/or a computation of a first ACF of the determined first scattered light intensity. The second wavelength may be selected in the other spectral range that is appreciably scattered by the particle species and remaining material in the mixture such that, in response to the emission of the light of the second wavelength into the mixture, an entirety of the mixture scatters the light of the second wavelength. The determined second scattered light intensity of the mixture based on the second DLS signal may be an intensity of the light of the second wavelength scattered by the entirety of the mixture, and the second particle size distribution may be yielded from the determined second scattered light intensity and/or a computation of a second ACF of the determined second scattered light intensity.

[0097] In further embodiments, the first light source and the second light source may be semiconductor laser diodes, dye lasers, gas lasers, solid-state lasers, optical parametric oscillators, and/or external-cavity diode lasers. The detector may include a photomultiplier tube or semiconductor elements such as an active-pixel sensor (APS), a reverse-biased light emitting diode (LED), a photodiode, a photoresistor, a phototransistor, or a quantum dot photoconductor. The detector may also include a single element detector, an array detector (one or more rows), or a line sensor (multiple elements along a one-dimensional array). The detector may provide continuous or sequential readouts from array sensors such as a charge-coupled device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) device. The apparatus may further include a polarizer positioned between the first and second light sources and the mixture such that the light of the first wavelength and the light of the second wavelength directed from the first and second lights sources, respectively, pass through the polarizer prior to reaching the mixture. The apparatus may yet further include a polarizer positioned between the mixture and the detector such that the light of the first wavelength and the light of the second wavelength scattered by the mixture is collected for detection by the detector. The mixture may be a solution, a colloid, and/or a suspension. The particle species may be a flavoring agent and/or a coloring agent. The apparatus may further include a lens configured to project one or more of the scattered light of the first wavelength or the light of the second wavelength by the mixture onto the line sensor. The detector may be configured to detect one or more of a forward scattered light of the first wavelength, a forward scattered light of the second wavelength, a backscattered light of the first wavelength, or a backscattered light of the second wavelength. One or more of the first light source or the second light source may be configured to direct the light of a first wavelength or the light of the second wavelength at predetermined increments of angle into the mixture, wherein the detector is in a fixed position relative to the mixture.

[0098] According to some examples, apparatuses to perform parallel multispectral DLS within a mixture that comprises a particle species are described. An example apparatus may include a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range, and a second light source configured to simultaneously emit light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range. The example apparatus may also include a first spectral filter corresponding to the first wavelength to collect the light of the first wavelength scattered by the mixture, and a first detector coupled to the first spectral filter and configured to detect a first DLS signal based on the light collected by the first spectral filter. The example apparatus may further include a second spectral filter corresponding to the second wavelength to collect the light of the second wavelength scattered by the mixture, and a second detector coupled to the second spectral filter and configured to detect a second DLS signal based on the light collected by the second spectral filter, where a particle size distribution of the particle species may be determined based on a difference between a first particle size distribution yielded from a determined first scattered light intensity of the mixture based on the first DLS signal and a second particle size distribution yielded by a determined second scattered light intensity of the mixture based on the second DLS signal.

[0099] In other examples, the spectral range and the other spectral range may be comprised of a visible light range, a UV light range, an IR light range, and/or a sub-spectral range. The first wavelength may be selected in the spectral range that is appreciably absorbed by the particle species such that, in response to the emission of the light of the first wavelength into the mixture, the particle species scatters a substantially lesser amount of the light of the first wavelength than remaining material in the mixture. The determined first scattered light intensity of the mixture based on the first DLS signal may be an intensity of the light of the first wavelength scattered by the remaining material, and the first particle size distribution may be yielded from the determined first scattered light intensity and/or a computation of a first ACF of the determined first scattered light intensity.

[00100] In further examples, the second wavelength may be selected in the other spectral range that is appreciably scattered by the particle species and remaining material in the mixture such that, in response to the emission of the light of the second wavelength into the mixture, an entirety of the mixture scatters the light of the second wavelength. The determined second scattered light intensity of the mixture based on the second DLS signal may be an intensity of the light of the second wavelength scattered by the entirety of the mixture, and the second particle size distribution may be yielded from the determined second scattered light intensity and/or a computation of a second ACF of the determined second scattered light intensity. [00101] In yet further examples, the first light source and the second light source may be semiconductor laser diodes, dye lasers, gas lasers, solid-state lasers, optical parametric oscillators, and/or external-cavity diode lasers. The detector may include a photomultiplier tube or semiconductor elements such as an active-pixel sensor (APS), a reverse-biased light emitting diode (LED), a photodiode, a photoresistor, a phototransistor, or a quantum dot photoconductor. The detector may also include a single element detector, an array detector (one or more rows), or a line sensor (multiple elements along a one-dimensional array). The detector may provide continuous or sequential readouts from array sensors such as a charge-coupled device (CCD) or a Complementary Metal-Oxide Semiconductor (CMOS) device. The mixture may be a solution, a colloid, and/or a suspension. The particle species may be a flavoring agent and/or a coloring agent.

[00102] According to some embodiments, apparatuses configured to determine a particle size distribution of a particle species within a mixture using multispectral DLS are described. An example apparatus may include a communication interface configured to facilitate

communication between the apparatus, one or more light sources, and a detector, a memory configured to store instructions, and a processor coupled to the communication interface and the memory. The processor may be configured to receive, through the communication interface, a first DLS signal and a second DLS signal, where the first DLS signal and the second DLS signal may be detected by the detector in response to a scattering of a light of a first wavelength and a light of a second wavelength by the mixture following a direction of the light of the first wavelength and the light of the second wavelength into the mixture, respectively. The processor may be also configured to determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[00103] In other embodiments, the processor may be further configured to compute a first ACF of the determined first scattered light intensity to yield the first particle size distribution and compute a second ACF of the determined second scattered light intensity to yield the second particle size distribution. The first wavelength may be selected in a spectral range that is appreciably absorbed by the particle species such that, in response to the direction of the light of the first wavelength into the mixture, the particle species scatters a substantially lesser amount of light than remaining material in the mixture. The processor may be configured to determine the first scattered light intensity of the mixture through a determination of an intensity of the light of the first wavelength scattered by the remaining material in the mixture. The processor may be configured to yield the first particle size distribution through a computation of a first ACF of the determined intensity of the light of the first wavelength scattered by the remaining material in the mixture. The first particle size distribution may be a particle size distribution of the remaining material in the mixture.

[00104] In other embodiments, the second wavelength may be selected in another spectral range distinct from the spectral range that is appreciably scattered by the particle species and remaining material in the mixture such that, in response to the direction of the light of the second wavelength into the mixture, an entirety of the mixture scatters the light of the second wavelength. The processor may be configured to determine the second scattered light intensity of the mixture through a determination of an intensity of the light of the second wavelength scattered by the entirety of the mixture. The processor may be configured to yield the second particle size distribution through a computation of a second ACF of the determined intensity of the light of the second wavelength scattered by the entirety of the mixture. The second particle size distribution may be a particle size distribution of the entirety of the mixture comprised of the particle size distribution of the particle species and a particle size distribution of the remaining material in the mixture.

[00105] In some examples, systems configured to perform multispectral DLS for particle size distribution measurement are described. An example system may include a communication interface configured to facilitate communication between a first apparatus and a second apparatus, the first apparatus may be configured to perform multispectral DLS in a mixture that comprises a particle species, and the second apparatus may be configured to determine a particle size distribution measurement of the particle species based on results of the multispectral DLS. The first apparatus may comprise a first light source configured to emit light of a first wavelength into the mixture, where the first wavelength may be selected in a first spectral range, and a second light source configured to emit light of a second wavelength into the mixture, where the second wavelength may be selected in a second spectral range distinct from the first spectral range. The first apparatus may also include a detector configured to detect a first DLS signal corresponding to a scattering of the light of the first wavelength by the mixture and a second DLS signal corresponding to a scattering of the light of the second wavelength by the mixture. The second apparatus may comprise a memory configured to store instructions, and a processor coupled to the memory and configured to receive, through the communication interface, the first DLS signal and the second DLS signal from the first apparatus, determine a first scattered light intensity of the mixture based on the first DLS signal to yield a first particle size distribution, determine a second scattered light intensity of the mixture based on the second DLS signal to yield a second particle size distribution, and determine the particle size distribution of the particle species based on a difference between the first particle size distribution and the second particle size distribution.

[00106] In other examples, the processor may be further configured to compute a first ACF of the determined first scattered light intensity to yield the first particle size distribution and compute a second ACF of the determined second scattered light intensity to yield the second particle size distribution. The processor may be configured to determine the first scattered light intensity of the mixture based on the first DLS signal through a determination of an intensity of the light of the first wavelength scattered by the remaining material in the mixture, and compute the first ACF of the determined first scattered light intensity to yield the first particle size distribution, where the first particle size distribution may be a particle size distribution of the remaining material in the mixture.

[00107] In further examples, the processor may be configured to determine the second scattered light intensity of the mixture based on the second DLS signal through a determination of an intensity of the light of the second wavelength scattered by the entirety of the mixture comprised of the particle species and the remaining material in the mixture and compute the second ACF of the determined second scattered light intensity to yield the second particle size distribution, where the second particle size distribution may be a particle size distribution of the entirety of the mixture comprised of the particle size distribution of the particle species and the particle size distribution of the remaining material in the mixture. The processor may be configured to determine the particle size distribution of the particle species based on a difference between the particle size distribution of the remaining material in the mixture and the particle size distribution of the entirety of the mixture. The remaining material may be comprised of one or more other particles or air bubbles. [00108] In yet further examples, the multispectral DLS may be performed sequentially or parallel. If the multispectral DLS is performed sequentially, the second light source may be configured to subsequently direct light of the second wavelength into the mixture. If the multispectral DLS is performed parallel, the second light source may be configured to simultaneously direct light of the second wavelength into the mixture. If the multispectral DLS is performed parallel, the first apparatus may further include a first spectral filter corresponding to the first wavelength to collect the light of the first wavelength scattered by the mixture, a second spectral filter corresponding to the second wavelength to collect the light of the second wavelength scattered by the mixture, a first detector coupled to the first spectral filter and configured to detect the first DLS signal, and a second detector coupled to the second spectral filter configured to detect the second DLS signal.

[00109] According to some examples, a method to perform dynamic light scattering (DLS) for particle size distribution measurement is described. The method may include performing, by a first apparatus, the DLS within a mixture that comprises a particle species by directing light of a particular wavelength into the mixture, where the particular wavelength is selected in a first spectral range; and detecting, through an array detector, a plurality of DLS signals in response to a scattering of the light of the particular wavelength by the mixture. The method may also include determining, by a processor communicatively coupled to the first apparatus, a particle size distribution of the particle species based on results of the DLS by receiving the plurality of DLS signals from the array detector; determining a plurality of scattered light intensities of the mixture based on the plurality of DLS signals to yield a particle size distribution; and

determining the particle size distribution of the particle species based on processing the plurality of scattered light intensities of the mixture.

[00110] According to other examples, the first spectral range may comprise wavelengths that are appreciably absorbed or appreciably reflected by the particle species. Processing the plurality of scattered light intensities may include one or more of integrating, comparing, adding, subtracting, and averaging the plurality of light intensities. The method may also include employing a lens to project the scattered light of the particular wavelength by the mixture onto the array detector. The array detector may be a line sensor. Detecting the scattering of the light of the particular wavelength by the mixture may include detecting one of a forward scattered light of the particular wavelength and a backscattered light of the particular wavelength. The method may further include directing the light of the particular wavelength at predetermined increments of angle into the mixture, wherein the array detector is in a fixed position relative to the mixture.

[00111] According to further examples, the method may further include computing a plurality of autocorrelation functions (ACFs) of the plurality of scattered light intensities to yield the particle size distribution. Determining the plurality of scattered light intensities of the mixture based on the plurality of DLS signals to yield the particle size distribution may include one or more of determining an intensity of the light of the particular wavelength scattered by a remaining material in the mixture to yield the particle size distribution; and computing the plurality of ACFs of the plurality of scattered light intensities scattered by the remaining material in the mixture to yield the particle size distribution. The particle size distribution may be a particle size distribution of the remaining material in the mixture. The mixture may be a solution, a colloid, or a suspension. The particle species may be one or more of a flavoring agent and a coloring agent. The particle species may include beta-carotene, the particular wavelength may be selected in a range of about 400 to 500 nanometers (nm).

[00112] According to some examples, an apparatus to perform sequential dynamic light scattering (DLS) within a mixture that comprises a particle species is described. The apparatus may include a light source configured to emit light of a particular wavelength into the mixture, where the particular wavelength is selected in a first spectral range. The apparatus may also include an array detector configured to detect a plurality of DLS signals in response to a scattering of the light of the particular wavelength by the mixture, where a particle size distribution of the particle species is determined based on processing the plurality of DLS signals to yield a particle size distribution from a determined plurality of scattered light intensities of the mixture based on the plurality of DLS signals.

[00113] According to some examples, the first spectral range may include wavelengths that are appreciably absorbed or appreciably reflected by the particle species. The plurality of DLS signals may be processed by one or more of integrating, comparing, adding, subtracting, and averaging the plurality of light intensities. The apparatus may also include a lens configured to project one or more of the scattered light of the particular wavelength by the mixture onto the array detector. The array detector may be a line sensor. The array detector may be further configured to detect one of a forward scattered light of the particular wavelength and a backscattered light of the particular wavelength. The first light source may be configured to direct the light of the particular wavelength at predetermined increments of angle into the mixture, where the array detector is in a fixed position relative to the mixture. The mixture may be a solution, a colloid, or a suspension. The particle species may include one or more of a flavoring agent and a coloring agent. The particle species may be beta-carotene, the particular wavelength may be selected in a range of about 400 to 500 nanometers (nm).

[00114] There is little distinction left between hardware and software implementations of aspects of systems; the use of hardware or software is generally (but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost vs. efficiency tradeoffs. There are various vehicles by which processes and/or systems and/or other technologies described herein may be effected (e.g., hardware, software, and/or firmware), and that the preferred vehicle will vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for mainly hardware and/or firmware vehicle; if flexibility is paramount, the implementer may opt for mainly software implementation; or, yet again alternatively, the implementer may opt for some combination of hardware, software, and/or firmware.

[00115] The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples may be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein may be implemented via application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs executing on one or more computers (e.g., as one or more programs executing on one or more computer systems), as one or more programs executing on one or more processors (e.g., as one or more programs executing on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and/or firmware would be well within the skill of one of skill in the art in light of this disclosure.

[00116] The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[00117] In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive (HDD), a compact disc (CD), a digital versatile disk (DVD), a digital tape, a computer memory, a solid state drive (SSD), etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.).

[00118] Those skilled in the art will recognize that it is common within the art to describe devices and/or processes in the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein may be integrated into a data processing system via a reasonable amount of experimentation. Those having skill in the art will recognize that a data processing system may include one or more of a system unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and/or control systems including feedback loops and control motors (e.g., feedback for sensing position and/or velocity of gantry systems; control motors to move and/or adjust components and/or quantities).

[00119] A data processing system may be implemented utilizing any suitable commercially available components, such as those found in data computing/communication and/or network computing/communication systems. The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively“associated” such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality may be seen as“associated with” each other such that the desired functionality is achieved, irrespective of architectures or intermediate components.

Likewise, any two components so associated may also be viewed as being“operably connected”, or“operably coupled”, to each other to achieve the desired functionality, and any two

components capable of being so associated may also be viewed as being“operably couplable”, to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically connectable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

[00120] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The term“plurality” as used herein refers to two or more elements in a list of elements. For example, a plurality of A may mean 2, 3, 4, etc. of A.

[00121] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g, the term“including” should be interpreted as“including but not limited to,” the term“having” should be interpreted as“having at least,” the term“includes” should be interpreted as“includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation, no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases“at least one” and“one or more” to introduce claim recitations.

However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles“a” or“an” limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases“one or more” or“at least one” and indefinite articles such as“a” or“an” ( e.g .,“a” and/or“an” should be interpreted to mean“at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of“two recitations,” without other modifiers, means at least two recitations, or two or more recitations).

[00122] Furthermore, in those instances where a convention analogous to“at least one of A, B, and C, etc.” is used, in general, such a construction is intended in the sense one having skill in the art would understand the convention (e.g,“a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase“A or B” will be understood to include the possibilities of“A” or“B” or“A and B.”

[00123] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as“up to,”“at least,” “greater than,”“less than,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 cells refers to groups having 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so forth.

[00124] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and

embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.