FIELD. OF. INVENTION

[0001] This invention generally relates to liquid fuels containing carbon dots and fuel additives containing carbon dots.

BACKGROUND

[0002] Nanofiiels refer to a colloidal suspension of a base fuel (e.g., diesel, biodiesel, fuel blends) and energetic/catalytic nanoparticles (NPs) (1-100 nm) as additives that include nanofibers, nanotubes, nanowires, nanorods, nanosheet, and droplets. ¹ ’ ² NPs have been developed for improving the combustion characteristics of conventional fuels by offering large reactive surface areas and high oxidation energies that are important to produce high-energy-density fuels while enhancing fuel economy and reducing pollutant emissions. In addition, studies of different carbon- and metal-based nanofuels have shown that the addition of some specific NPs to certain base fuels may increase catalytic activity, ignition probability, volumetric energy density, volumetric heat release rates, and combustion rates while reducing ignition delay, pollutant emissions, and soot formation, ³ ’ ⁴

[0003] Addition of NPs to conventional fuels can affect the combustion process by modulating the processes of conductive, convective, and radiative heat transfer to fuel droplets. ⁵ ' ¹² Sabourin et al. observed an enhancement in the burning rate of monopropellant nitromethane mixed with functionalized graphene sheets. ¹³ They concluded that the enhancement of thermal radiation absorption and thermal conductivity by adding these NPs are the two key mechanisms responsible for this enhancement. Thermal conductivity is highly affected by the species of added NPs including their loading concentrations, fuel temperature, and particle suspension and size. Typically, it can be enhanced by increasing the loading and temperature and decreasing the size of added NPs. ¹⁴ ’ ¹⁵ The improvement in thermal conductivity' can be ascribed to the Brownian motion of the N Ps and the generation of a solid-liquid interface thermal transport inside the droplet. ¹ ’ ¹⁶ Nonetheless, an opposing effect may be observed with increased loading. ⁵⁵ Addition of NPs can also enhance the radiation and convective heat transfers by inducing circulatory flow inside the nanofuel droplet. ^{6- 11} ’ ¹⁷

[0004] Since most conventional liquid fuels are transparent, adding NPs decreases the droplets’ optical transmittance, which increases the radiation absorption, ⁶ ’ ^{10, 11} The level of increase largely depends on the emission wavelength and droplet size. The circulatory flow inside the droplet can lead to accumulation of NPs on the droplet surface, creating a porous shell. ¹¹ The formation of porous shells inhibits the convection heat transfer from the surroundings to the liquid fuels, which in turn lowers the evaporation rate. ¹⁸ Meanwhile, the addition of NPs can increase the droplet temperature, ¹⁹ enhancing permeation of the liquid fuel through the porous shell and increasing the evaporation rate.

[0005] These shell formations and temperature increases mainly depend on the species of added NPs and the loading amount Gan et al. studied the effect of radiation absorption on the evaporation rate of ethanol-based nanofuels by applying a mercury lamp and observed that with the same mass loading and applied radiation intensity, addition of multi-walled carbon nanotubes achieved a much more enhanced evaporation rate in comparison to the addition of carbon NPs. ¹⁰ Most of the aforementioned studies involved the concept of droplet combustion to assess the effects of NPs on the combustion behaviors of conventional fuels. For any combustion system, fuel droplets are the elemental building blocks as these systems utilize atomization of bulk fuels to convert them to fine sprays, which are mainly arrays of fine droplets. Atomization of liquid fuels is important for internal combustion and gas turbine engines, as the characteristics of the droplets determine the combustion performance and pollutant formation. ²⁰

[0006] From the viewpoint of practical application, various NPs have been applied as fuel additives to evaluate their prospects in compression ignition engines. ²¹ ' ²³ It was found that certain nano-additives resulted in the reduction of CO, HC, and NOx emissions. Additionally, a reduction in ignition delay and brake-specific fuel consumption with an increase in brake thermal efficiency were observed for certain additives. However, there are many limitations that restrict the use of nanofuels in practical combustors, which include the inherent tendency of NPs to aggregate, the impacts of different NPs on pre-ignition reaction rates, ²⁴ the formation of oxide layers, ²⁵ and incombustibility of some nano-additives.

[0007] Carbon- and metal-based NPs were studied in most of the previous studies. However, metal-based nano-additives are hazardous in nature, detrimental to human health and the environment. Metal-based nano-additives can harm cells, the skin, the respiratory system, the digestive system, and the central nervous system. ²⁶ Side effects of different metal-based nanoadditives were studied extensively, which include DNA damage (magnesium-based nanoadditives); ²⁷ phytotoxicity (alumina-based nano-additives); ²⁸ chronic inflammation and cytotoxicity (cerium-based nano-additives); ⁶ cell injury (iron-based nano-additives); ²⁹ and inflammation and cell death (titanium-based nano-additives). ³⁰

[0008] Considering these adverse effects of metal-based nano-additives, there is a need for less toxic, cost-effective, and combustible non-metallic carbon-based nano-additives. ³¹ Previous studies demonstrated that certain carbon-based nano-additives including multi-walled carbon nanotubes, graphene NPs, graphite oxide, and carbon black could be utilized to modify the combustion behaviors of conventional liquid fuels. ⁶ " ¹² Currently, research initiatives aim at searching for more cost-effective and biocompatible carbon-based nano-additives that not only catalyze the combustion process but also address those aforementioned physicochemical limitations.

[0009] Carbon dots (CDs) are a promising class of carbon-based nanomaterials discovered unintentionally in the early 20 ^th century. ³² CDs possess many properties of interest such as small particle size (less than 10 nm), good biocompatibility, nontoxicity, high water solubility, photoluminescence, abundant surface functional groups and tunable surface functionality, and high surface-area-to-volume ratio. ³³ Due to these unique properties, CDs have been utilized by different sectors in diverse applications such as nanomedicine, drug delivery, bioimaging, sensing, photocatalysis, additive manufacturing, and energy conversion. ^34-37 Previous studies also reported that certain CDs could increase the thermal conductivity of phase-change materials, ³⁸ and modify the combustion efficiency in a diesel engine. ³⁹ Also, recently, a special type of CDs called gel-like G-CDs (G-CDs) have been applied to enhance the regression rate and combustion efficiency of hybrid rocket fuels. ⁴⁰

[0010] There is a need in the art for nanoadditives for liquid fuels to improve combustion performance and other production and performance characteristics.

[0011] The present invention is directed to a liquid fuel composition comprising carbon dots. In a preferred embodiment, the liquid fuel is jet fuel.

[0012] The present invention is also directed to a fuel additive comprising carbon dots.

[0013] In one preferred embodiment, the carbon dots employed in the additives and fuels according to the invention are gel-like carbon dots (G-CDs). In a further preferred embodiment, the G-CDs can be synthesized on large scale within a short timeframe. [0014] In another preferred embodiment, the carbon dots employed in the additives and fuels according to the invention are combined with a surfactant In a preferred embodiment, the surfactant is compatible with the fuel, has the ability to lower surface tension and enables the carbon dots to remain in solution. In a further preferred embodiment, the surfactant is Span 80 (sorbitan monooleate) or a component of a biodiesel.

[0015] In another preferred embodiment, the carbon dots employed in the additives and fuels according to the invention are modified. In one preferred modification, the carbon dots are modified to add a saturated hydrocarbon tail (C5-C18) to improve the lipophilicity/hydrophobicity of the carbon dots. In another preferred modification, the carbon dots are modified to confer a uniform charge (+ or -) so that the carbon dots act as dispersants and further preferably prevent clumping.

[0016] The present invention is further directed to a fuel comprising a liquid base fuel and a G- CD, wherein the fuel exhibits improved stability, combustion rate, ignition delay, total combustion time, puffing, and/or flame propagation characteristics.

[0017] The present invention is further directed to a fuel additive comprising carbon dots that are gel-like carbon dots.

[0018] In a preferred embodiment, the carbon dots employed in the additives and fuels according to the invention are substantially nonmetallic or free of any metallic component.

[0019] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic G-CDs, wherein the combustion rate is increased at least 5, 10, 15 or 20% over the combustion rate of the fuel without the fuel additive.

[0020] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic gel-like carbon dots, wherein the combustion rate is increased at least about 4%, 10%, 12%, 15%, 18%, 23% or 25% over the combustion rate of the fuel without the fuel additive. In a further preferred embodiment, the increase in combustion rate is achieved at a fuel additive mass loading of about 3% (w/w).

[0021] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic gel-like carbon dots and a surfactant, wherein the ignition delay is decreased at least 5, 10, 12, 14, 16, 18 or 20% relative to the ignition delay of the fuel without the fuel additive. In a further preferred embodiment, the ignition delay is decreased by at least about 4, 8, 11 or 18% relative to the ignition delay of the fuel without the fuel additive. [0022] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic carbon dots and a surfactant, wherein the total combustion time is reduced at least about 5, 10, 15, 20 or 25% over the total combustion time of the fuel without the fuel additive. In a further preferred embodiment, the total combustion time is reduced by at least about 6, 13, 19 or 20% over the total combustion time of the fuel without the fuel additive.

[0023] The accompanying drawings, which are incorporated into and constitute a part of this specification, illustrate one or more example aspects of the present invention and, together with the detailed description, serve to explain their principles and implementations.

[0024] Figure 1 is a graph showing changes in combustion rates of nanofuels according to the invention compared to pure Jet-A.

[0025] Figure 2 is a graphical representation of changes in ignition delay of nanofuels according to the invention compared to pure Jet-A.

[0026] Figure 3 is a graphical representation of changes in total combustion time of nanofuels according to the invention compared to pure Jet-A.

[0027] Figure 4 shows puffing in multiple directions on 3% (w/w) G-CDs according to the invention plus Jet-A nanofuel droplet. Here t=0 ms defines as the start of the experiment [0028] Figure 5 shows flame propagation of a) pure Jet-A fuel droplet, and b) 3%(w/w) G-CDs + Jet-A nanofuel droplet according to the invention. Here ti=0 ms defines as the start of the ignition.

[0029] The present invention is directed to liquid fuels containing carbon dots and fuel additives containing carbon dots.

[0030] The carbon dots employed in the additives and fuels according to the invention are gel-like carbon dots (G-CDs). In a further preferred embodiment, the G-CDs can be synthesized on large scale within a short timeframe. For example, the G-CDs may be prepared by a method in which (i) 1,2-ethylenediamine (EDA) is heated to about 140-180 * C; (ii) citric acid is added; (iii) the mixture of EDA and citric acid is stirred until the citric acid is dissolved in the EDA; (iv) the mixture is cooled to room temperature; and (v) the unreacted EDA is discarded leaving the G-CDs. The G-CDs may then be washed, for example, with acetone. The molar ratio of EDA to citric acid is preferably approximately 15 to 1.

[0031] The liquid fuel to which the carbon dots are added can be any liquid fuel including jet fuel and diesel fuel.

[0032] The G-CDs can be added to the liquid fuel in any amount that provides suitable properties. In a preferred embodiment, the concentration of G-CDs in the liquid fuel is between about 0.5 and 10 w/w%, 0.5 and 5 w/w%, or 0.5 and 3 w/w%. In another preferred embodiment, the concentration of G-DCs in the liquid fuel is about 0.5, 1 , 1.5, 2, 3, 4 or 5 w/w%.

[0033] In one embodiment, the carbon dots employed in the additives and fuels according to the invention are combined with a surfactant. In a preferred embodiment, the surfactant is compatible with the fuel, has the ability to lower surface tension and enables the carbon dots to remain in solution. In a further preferred embodiment, the surfactant is Span 80 (sorbitan monooleate) or a component of a biodiesel. The biodiesel component can be from, for example, a biodiesel feedstock of tallow, lard, coconut, palm kemal, palm, safflower, peanut, cottonseed, com, sunflower, soybean, rapeseed, linseed, mustard or combinations thereof.

[0034] In another embodiment, the carbon dots employed in the additives and fuels according to the invention are modified. In one preferred modification, the carbon dots are modified to add a saturated hydrocarbon tail (Cs-Cu) to improve the lipophilicity/hydrophobicity of the G-CDs. In another preferred modification, the carbon dots are modified to confer a uniform charge (+ or -) so that the carbon dots act as dispersants and further preferably prevent clumping.

[0035] The fuel according to the invention comprising a liquid base fuel and G-CDs preferably exhibits improved characteristics over the liquid base fuel alone, including improved stability, combustion rate, ignition delay, total combustion time, puffing, and/or flame propagation characteristics.

[0036] The present invention is further directed to a fuel additive comprising carbon dots that are gel-like carbon dots.

[0037] In a preferred embodiment, the carbon dots employed in the additives and fuels according to the invention are substantially nonmetallic or free of any metallic component. [0038] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic G-CDs, wherein the combustion rate is increased at least 5, 10, 15 or 20% over the combustion rate of the fuel without the fuel additive.

[0039] The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic gel-like carbon dots, wherein the combustion rate is increased at least about 4%, 12%, 18% or 23% over the combustion rate of the fuel without the fuel additive. In a further preferred embodiment, the increase in combustion rate is achieved at a fuel additive mass loading of about 3%.

[00401 The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic gel-like carbon dots and a surfactant, wherein the ignition delay is decreased at least 5, 10, 12, 14, 16, 18 or 20% relative to the ignition delay of the fuel without the fuel additive. In a further preferred embodiment, the ignition delay is decreased by about 4, 8, 11 or 18% relative to the ignition delay of the fuel without the fuel additive.

[00411 The present invention is further directed to a fuel composition comprising a fuel additive comprising nonmetallic carbon dots and a surfactant, wherein the total combustion time is reduced at least 5, 10, 15, 20 or 25% over the total combustion time of the fuel without the fuel additive. In a further preferred embodiment, the total combustion time is reduced by about 6, 13, 19 or 20% over the total combustion time of the fuel without the fuel additive.

[0042] This disclosure reports a study on the impacts of a novel class of carbon-based nanomaterials, namely gel-like carbon dots (G-CDs), at various particle loading levels, on the combustion performances of conventional aviation Jet-A fuel. Colloidal suspensions of Jet-A and G-CDs were prepared with different particle loadings by ultrasonication.

[0043] The G-CDs showed prospects to be considered as a promising nano-additive for conventional hydrocarbon-based liquid fuels.

[0044] Example 1. Synthesis of gel-like carbon dots (G-CDs)

[0045] Argon flux (ultra-high purity, Airgas, Miami, FL, USA) was applied to empty O2 in a 100 mL three-necked round-bottom flask, for 5 min. Then, 30 mL of 1,2 -ethylenediamine (EDA) (>99.0%, MP Biomedicals, Irvine, CA, USA) was transferred into the flask and heated up to 160 °C with constant stirring in a paraffin oil bath on a hotplate (Chemglass, OptiMag-st). When the temperature reached 160 °C, 6 g of citric acid (99.5-100%, VWR, West Chester, PA, USA) was added into the system with vigorous stirring. This step was sustained for 50 min until a complete dissolution of citric acid in EDA was achieved. Argon flux was utilized through the whole reaction to prevent EDA from oxidization. After cooling the system down to the room temperature, the G- CDs were generated at the bottom of the flask The unreacted EDA supernatant was discarded, and the G-CDs were washed three times with 60 mL acetone (99.9%, VWR, West Chester, PA, USA) in total for better purification. During each wash, Vortex mixer and ultrasonication bath were consecutively applied and each procedure proceeded for 1 min. Subsequently, the acetone remnant in the G-CDs was evaporated by air flux. Thai, 8-10 g of the G-CDs were obtained and sealed for combustion testing. All the chemicals were used without further treatment.

[0046] Example 2. Preparation of nanofuels

[0047] Nanofuel suspensions were prepared in 20 ml disposable scintillation vials by using an ultrasonic disruptor with a 3/16” probe for 15 minutes, with 4 s long pulses and at 30% amplitude. Span 80 (Sorbitan Monooleate, C ₂₄ H ₄₄ O ₆ ) was added as surfactant to the base fuel at a mass concentration of 1.50% to make the suspension stable, homogeneous and to avoid coagulation of G-CDs. The prepared nanofuels were 0.50, 1.00, 1.50, 2.00, and 3.00% w/w G-CDs with Jet-A as the base fuel.

[0048] Example 3. Stability testing of nanofuels

[0049] Stability of the nanofuels prepared in Example 2 was observed by visual inspection. Under normal light, pure Jet-A had a transparent appearance while the nanofuels had cloudy appearance. Photoluminescence characteristics of G-CDs were utilized for the visual inspection.

[0050] Colloidal suspension of G-CDs and Jet-A showed bluish color under UV light while pure Jet-A showed no color changes. A commercially available LED based UV flashlight was used for the visual inspection (Wavelength 390-395 nm). Also, sedimentation at the bottom were monitored for the stability period. All the nanofiiels were stable for at least 48 hours. Experiments were performed within 2 hours of preparation to maintain the homogeneity of the nanofuels during the experiment period.

[0051] G-CDs process unique photoluminescence (PL) characteristics. For example, from the fluorescence spectra and normalized spectra, G-CDs show excitation-wavelength-dependent PL in the low energy region (X>400 nm), whereas they show wavelength-independent PL in the high- energy region (X <400 nm). This indicates G-CDs based nanofuel show photoluminescence behaviors under the present of UV light. So, if the G-CDs is dispersed evenly into base fuel, the nanofuel should illuminate certain color (for current case it is bluish). This can be considered as an indicator to investigate the stability of the nanofuel by observing the changes in illuminated color. When comparing the appearances of pure Jet-A and nanofuel under UV, it was observed that pure Jet-A didn’t show any PL characteristics while the prepared nanofuel appeared as bluish.

[0052] Example 4. Combustion rate testing of nanofuels

[0053] Droplet combustion was conducted by suspending a millimeter-sized spherical droplet upon three 16 pm silicon carbide wires and ignition using hot wire loops. The combustion process was captured with both a high-speed CCD camera and a CMOS camera. The resulting images were post-processed to analyze the combustion characteristics of the colloidal suspensions at different particle loading levels.

[0054] Combustion rate quantitative data was obtained with a CCD camera (IDTX-StreamVision XS-3 CCD) which generated 8-bit gray-scale images with a resolution of 948x552 pixels at a rate of 1000 frames per second. The post processing software was Image!. Black and white images were used to extract the data of droplet area evolution with time by using the Image! software. These data were utilized to calculate the combustion rate (Figure 1) of different fuels through the d ² - law of combustion.

[0055] Example 5. Ignition delay testing of nanofuels

[0056] Ignition delay was determined with a CMOS camera (Casio EXILIM Pro EX-F1) which generated RGB images with a resolution of 432x192 pixels at a rate of 600 frames per second. The post processing software was ImageJ. Results are shown in Figure 2.

[0057] Ignition delay is defined as the time difference between the initiation of the heating and the appearance of flame. The RGB images were studied to locate the moment of the initiation of the heating which can be seen with the appearance of the indicator light in the image. Thai the RGB images were investigated for the appearance of flame. By calculating the frame difference and converting it to time difference the ignition delay period is quantified. This ignition delay period is further normalized with the square of the droplet’s initial diameter to offset the effect of differences in initial droplet sizes.

[0058] Example 6. Total combustion time testing of nanofuels

[0059] Total combustion time was determined with a CMOS camera (Casio EXIT1M Pro EX-F1) which generated RGB images with a resolution of 432x192 pixels at a frame rate of 600 frames per second. The post processing software was Image!. [0060] Total combustion time (TCT) was defined as the time differences between the appearance of the first flame and the extinction of the flame. The RGB images were studied to locate these two frames. By calculating the frame difference and converting it to time difference the TCT is quantified. This TCT was further normalized with the square of the droplet’s initial diameter to offset the effect of differences in initial droplet sizes. Results are shown in Figure 3.

[0061] Addition of the G-CDs generally increased the combustion rate (Figure 1) and decreased the ignition delay (Figure 2), and total combustion time (Figure 3) compared to the base fuel. This increase in combustion rate may result in higher flame propagation velocities in internal combustion engines which in turn resulted in higher efficiency. In internal combustion engines, the ignition delay is defined as the time between fuel injection and start of the ignition. Shorter ignition delay corresponds to smoother start and operation of jet engine and diesel engine. Also, ignition delay is inversely related to cetane number of fuels. So, the lower ignition delay results in higher cetane number fuel, which means the fuel will bum more evenly and completely. This may result in higher-quality exhaust air, reducing soot formation, reducing particulate matter emulsion, and reducing generation of unbumt hydrocarbon. Also, the G-CDs with 20% oxygen can act as an additional oxygenated component in the fuel, ⁴¹ which results in cleaner burning, reducing emissions especially unbumt hydrocarbon and soot. The highest increase in combustion rate of 23% was observed at 3.00% mass loading, and the highest decrease in ignition delay of 18% was observed at 1.50% mass loading. The highest reduction in total combustion time of 20% was observed at 3.00% mass loading.

[0062] Example 7. Puffing phenomenon testing of nanofuels

[0063] Puffing is the incident of bubble formation inside a fuel droplet and subsequent ejection of satellite droplets. This happens due to the volatility differences of different components of a multicomponent fuel, which results in preferential evaporation. High volatile component gets superheated during combustion, which is entrapped by the low volatile components. This entrapment results in pressure buildup inside the bubble. When the pressure is sufficient, bubble gets broken, and this pressure release ejects satellite droplets from the main droplet. This breakup of droplets results in better fuel-air mixing in internal combustion engines. This leads to more complete burning of fuels, which increases engine efficiency and reduces emissions. To incorporate puffing, mixing of water or other high volatile components with the fuels is a common practice. Another way to incorporate puffing is introduction of nano-additives. As nano-additives have typically higher thermal conductivities, localized boiling of fuel components occurs inside a droplet inducing bubble formation and subsequently causing puffing.

[0064] Puffing phenomena qualitative data was obtained with a CCD camera (IDTX- StreamVision XS-3 CCD) which generated 8-bit gray-scale images with a resolution of 948x552p at a rate of 1000 frames per second. The post processing software was Image! .

[0065] Each of the B&W images were investigated for the appearances of puffing with different characteristics. Results are shown in Figure 4.

[0066] An increase in puffing phenomenon was observed with the addition of G-CDs. Jet-A fuel is a kerosene-based jet fuel that consists of a wide range of hydrocarbons. Although the Jet-A fuel has low volatility compared to gasoline or diesel but at the end of steady combustion period, preferential evaporation occurs between the different hydrocarbons left in the droplet due to volatility differences. With the addition of G-CDs, there was an increase in nucleation sites inside the droplet, which in turns increased the puffing occurrences in nanofuels. As a result, puffing was observed in multiple directions with a higher intensity in nanofuels containing higher mass loading of G-CDs (Figure 4). It was found that puffing occurrences increased up to five times at 3.00% G-CDs mass loading compared to pure Jet-A fuel droplet Puffing occurrences and apparent mass ejection speed were quite similar between up to 1.00% G-CDs mass loading and pure Jet-A.

[0067] Example 8. Mass ejection speed testing of nanofuels

[0068] From the 1.50% G-CDs mass loading, there was a rapid increase in apparent mass ejection speed as well as puffing occurrences. Pure Jet-A droplet ejected mass or satellite droplets at an average speed of 0.419 m/s while a rapid increase in satellite droplet’s apparent ejection speed was observed from 1.50% G-CDs mass loading. For 1.50% G-CDs mass loading, the average apparent mass ejection speed was observed at around 0.685 m/s that increased up to around 0.893 m/s for 3.00% G-CDs mass loading. The apparent mass ejection speed was more than double for 3.00% G-CDs mass loading compared to pure Jet-A. This increase in mass ejection speed distorted the flame structure that can be observed from Figure 4.

[0069] Mass ejection speed qualitative data was obtained with a CCD camera (IDTX- Stream Vision XS-3 CCD) which generated 8-bit gray-scale images with a resolution of 948x552p at a rate of 1000 frames per second. The post processing software was Image!.

[0070] Appeared mass injection speed were calculated from the B&W images where satellite droplets were observed. Then the distance traveled by the satellite droplets was measured from the corresponding images/frames (1-3 frames) and the time was calculated from the frame differences. Mass ejection speed was termed as appeared mass ejection speed as the images signify appeared 2D plane.

[0071] Example 9. Flame propagation testing of nanofuels

[0072] Flame propagation qualitative data was obtained with a CMOS camera (Casio EXILIM Pro EX-F1) which generated RGB images with a resolution of 432x192 pixels at a rate of 600 frames per second. The post processing software was ImageJ.

[0073] Each of the RGB images were investigated for locating the frameflmages where different flame characteristics were observed. See Figure 5.

[0074] It will be appreciated that in the development of any actual implementation of the present disclosure, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, and that these specific goals will vary for different implementations and different developers. It will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

[0075] Furthermore, it is to be understood that the phraseology or terminology used herein is for the purpose of description and not of restriction, such that the terminology or phraseology of the present specification is to be interpreted by the skilled in the art in light of the teachings and guidance presented herein, in combination with the knowledge of the skilled in the relevant art(s). Moreover, it is not intended for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such.

[0076] The various aspects disclosed herein encompass present and future known equivalents to the known modules referred to herein by way of illustration. Moreover, while aspects and applications have been shown and described, it would be apparent to those skilled in the art having the benefit of this disclosure that many more modifications than mentioned above are possible without departing from the inventive concepts disclosed herein. REFERENCES

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