ELMEGREEN BRUCE (US)
IBM UK (GB)
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CLAIMS 1. A carbon dioxide membrane filter comprising at least one graphene sheet interspersed with holes that have open carbon bonds filled with another element, each of the holes tipped with said another element making up a crown pore. 2. The carbon dioxide membrane filter of claim 1, wherein said another element includes oxygen. 3. The carbon dioxide membrane filter of claim 1, wherein said another element includes nitrogen. 4. The carbon dioxide membrane filter of claim 1, further including a porous substrate wherein the graphene sheet is placed on the porous substrate for support against driving pressure. 5. The carbon dioxide membrane filter of claim 4, wherein the porous substrate has a honeycomb-like array of channels. 6. The carbon dioxide membrane filter of claim 4, wherein the porous substrate has an anodic aluminum oxide pore-structure. 7. The carbon dioxide membrane filter of claim 1, wherein the crown pore is created by taking away six carbon atoms from the graphene sheet and replacing carbon edges of a hole created by removal of the six carbon atoms with atoms of said another element. 8. The carbon dioxide membrane filter of claim 1, wherein the graphene sheet has an irregular mesh shape. 9. The carbon dioxide membrane filter of claim 1, wherein the graphene sheet is stretched to enlarge the crown pore. 10. The carbon dioxide membrane filter of claim 1, wherein the graphene sheet is stretched relatively by at least one percent to enlarge the crown pore. 11. The carbon dioxide membrane filter of claim 1, wherein the crown pore is symmetric with respect to a direction of molecular flow of carbon dioxide through the crown pore. 12. The carbon dioxide membrane filter of claim 1, wherein the graphene sheet has a density of crown pores such that there exists at least one crown pore per every 5 nanometer by 5 nanometer square area. 13. The carbon dioxide membrane filter of claim 1, wherein the carbon dioxide membrane filter includes multiples of said at least one graphene sheet arranged in series. 14. A carbon dioxide membrane filter comprising a graphene sheet of carbon in a repeated hexagonal pattern, interspersed with holes that have open carbon bonds filled with another element, wherein each of the holes tipped with said another element makes up a crown pore, wherein the graphene sheet is shaped to a cylindrical structure having a zig-zag surface pattern with crown pores, wherein carbon dioxide is permitted to enter, via the crown pores, from a first side of the cylindrical structure to a second side of the cylindrical structure, wherein the first side and the second side have different pressures. 15. The carbon dioxide membrane filter of claim 14, wherein the first side is outside of the cylindrical structure and the second side is inside of the cylindrical structure, wherein the outside has higher pressure than the inside. 16. The carbon dioxide membrane filter of claim 14, wherein the first side is inside of the cylindrical structure and the second side is outside of the cylindrical structure, wherein the inside has higher pressure than the outside. 17. A graphene sheet with at least one hole, wherein edges of said at least one hole have exposed carbon atoms bonded with another element to make a crown pore. 18. The graphene sheet of claim 17, wherein said another element includes oxygen. 19. The graphene sheet of claim 17, wherein said another element includes nitrogen. 20. A method of fabricating a carbon dioxide membrane filter comprising: causing ion-beam-sculpting on a graphene supported by a porous substrate; and performing oxidative etching to enlarge pores in the graphene, wherein carbon atoms exposed at the edges of the pores are bonded with another element. 21. The method of claim 20, wherein said another element includes oxygen. 22. A method of carbon capture, comprising: filtering carbon dioxide from flue gas using graphene having pores tipped with oxygen, wherein the flue gas is provided in an area of a first side of the graphene, and the carbon dioxide in the flue gas is caused to be transported to an area of a second side of the graphene via at least one of the pores. 23. The method of claim 22, further including applying higher pressure in the area of the first side than in the area of the second side. 24. The method of claim 22, the method includes a two-stage filter wherein a first membrane filter is used before a second filter, the second filter comprising the graphene having pores tipped with oxygen. 25. The method of claim 22, wherein a muti-layered structure having layers of the graphene are used to filter carbon dioxide. |
[0043] Whether other gas molecules can go through the crown pore (when γ=0) can also be investigated. As shown in Fig. 4, potential energies for CO and O 2 at z=0 are repulsive, suggesting that the crown pore repels these two molecules. Water can go through the pore because the hydrogens on each side of the oxygen in water are positively charged and attract to the negative oxygens at the edge of the pore. Once one of the hydrogens goes in, the rest of the molecule passes through as well. Hydrogen can go through the pore as well because of its small size, so the crown-pore can be used to separate H 2 from gas molecules larger than H 2 . Fig. 4 also includes results for N 2 and CO 2 . Because the gas separation properties of the crown pore arise from its electronic charge distribution, the crown-pore can be used to selectively trap and transmit all molecules or ions that are isoelectronic to CO 2 , such as nitrous oxide N 2 O, cyanogen fluoride NCF and nitronium NO 2 .
[0044] Fig. 4 shows potential energy distributions for various gas molecules as a function of distance to the crown pore (γ=0) in an embodiment. The potential energy distribution can differ dramatically when the graphene is stretched slightly. As the graphene stretches uniformly along both x and y axes (e.g. strain γ = 1.0 %), the potential barrier near the plane of the graphene decreases or disappears (Fig. 2) so that the potential energy landscape for CO 2 becomes purely attractive. At this point, CO 2 can enter the crown pore more easily. In an aspect, CO 2 does not have to go straight into the pore (as done in DFT calculations) because the potential well near the pore entrance can guide a CO 2 molecule that is not exactly aligned along the z axis to enter the pore.
[0045] Fig. 5 illustrates in an embodiment, CO 2 's drifting through the crown-pore containing graphene sheet, driven by pressure difference (P1>P2). Dots indicted by 504 represent N2 molecules, and dots indicated by 502 represent CO 2 molecules. The crown-pore containing graphene is shown at 506, and the porous substrate is shown at 508.
[0046] In an embodiment, the graphene sheet or film can be stretched to a degree. In an embodiment, at a relative stretching of 1.0% or more (e.g., of graphene film), the crown pore passes CO 2 and H 2 O and repels N 2 . In an embodiment, this can be a filter to separate CO 2 from N 2 . For example, CO 2 passes through oxygen crown pores in graphene. The CO 2 and H 2 O can be separated from each other as well, for example, by lowering the temperature, at which point H 2 O condenses out of the gas and forms a liquid on the walls of the chamber, leaving CO 2 in the gas phase. [0047] In an embodiment, the crown pore is symmetric with respect to the direction of molecular flow. CO 2 can pass back through the pore to the flue gas side as it can pass from the flue gas to the filtered side. In an embodiment, to get a net separation of CO 2 from N 2 in the flue gas, there can be a partial pressure difference between the two sides so that the partial pressure and CO 2 collision rate are higher on the flue gas side than the filtered side. Additionally, CO 2 molecules that become trapped in the crown pore can be knocked out by the next gas molecule that hits it, with the partial pressure difference. [0048] With a pressure difference between the two sides of the graphene sheet, a substrate can be provided to support the sheet and clamped to it. One embodiment of this support can be a hierarchical nanopore structure, where a graphene nanosheet with a high density of crown pores (e.g., 1 in every 5nm-by-5nm square) rests on a porous substrate. The porous substrate can be a honeycomb-like array of channels or an anodic aluminum oxide (AAO) pore-structure. A 2-dimensional (2D) cross-section of the graphene sheet attached to the porous support structure is shown in Fig.5. Due to the pressure difference, the graphene sheet is bent towards/into substrate channels. This bending stretches the graphene sheet, which promotes the CO 2 ’s transition through the crown pores. The graphene’s Young’s modulus is about 2.4 TPa, which yields a strain of 0.15% in the bent graphene on a 6.6-mm-in-diameter pore under a pressure difference of 1 bar. Assuming a linear stress-strain relation at a small stretching, a pressure difference of 7 bar (assuming a diameter of pore in the substrate ~ 6.6 mm) can be enough to yield a strain of 1.0% in the bent graphene sheet. This level of strain may further enhance the passage of CO 2 through the crown pore, as discussed above. Fig.7 shows an example of a porous substrate, which can act as support for graphene film. [0049] In an embodiment, with the crown pore graphene on a substrate, for example, shown in Fig.5, the permeance to CO 2 can depend on the pressure. At a low pressure, the graphene is stretched less and the permeance is lower. Therefore, the graphene on a substrate can be operated as a valve where CO 2 passes through at high pressure and not at low pressure. This blocking at a low pressure can be used to block the backwards flow of CO 2 from the CO 2 receiving chamber into the flue gas side of the membrane. Thus, the pressure can act cyclically with filtering at high pressure when the partial pressure in the flue gas side of the membrane exceeds the partial pressure in the CO 2 receptacle outside the membrane, and with no backsplash of CO 2 from the receptacle into the flue gas side during low pressure. The membrane plus substrate can therefore be a one-way valve under these circumstances. The optimum pressure needed for filtering the CO 2 out of flue gas can be determined by measurement. In an aspect, it can be a function of how much each piece of graphene bends and changes the local strain as the pressure increases. A pressure on the flue gas side that is too much larger than the pressure on the outside could break the graphene. Experimentally, the maximum pressure difference can be as high as 100 bars. [0050] The symmetry of the crown pore graphene filter also implies that crushed graphene fragments randomly filled with crown pores can be assembled into an irregular mesh to make a macroscopically amorphous filter. For example, it is possible to prepare thin membranes by spin casting graphene nanosheets onto a flat surface. This method can yield highly interlocked layer structures. Additionally, laminates can be formed with a collection of micron-sized graphene crystallites, forming an interlocked layered structure that can be air-tight. When introducing crown pores in these micron-sized graphene sheets, each pore in the mesh can pass CO 2 and repel N 2 , providing a selectively diffusive barrier that separates these two gases. In another embodiment, a large crown-pore containing graphene sheet (e.g., 4-inches-by-4-inches) can be tiled on the porous substrate. [0051] In an aspect, using crown pores, the pore structure in graphene is stable (e.g., cannot be further oxidized) and its performance can be theoretically quantified. It can also be expected to have a higher selectivity for CO 2 /N 2 for a graphene membrane with crown-pores than for other porous membranes. [0052] In an embodiment, temperatures less than 600 Celsius (C), which is generally the case for flue gas environments (e.g., in the chimney), can provide for the stability of the graphene. [0053] It can be possible to make multiple crown pores in a small graphene nanoflake and the density of crown pores in graphene can be as high as 10 12 /cm 2 . Additionally, one can increase the surface area to allow more pores for CO 2 to pass through. Fig.6 shows in an embodiment, a cylindrical zig-zag membrane with a lot of supported area to fit in a small volume. In an embodiment, the pressure at the center of the cylinder is lower than the one outside. In another embodiment, the pressure at the center of the cylinder is higher than the one outside. For example, the outside and the inside can have different pressures. Generally, for example, there can be some pressure difference between the inside and the outside regions. In an embodiment, in this device, CO 2 molecules can be driven from the outside, through the membrane and get into the central channel of the cylinder. The zigzag surface provides more surface area than a regular cylindrical surface. One benefit can be that the modular structure (Fig.6) can minimize the down time during replacement of contaminated ones. For particles adsorbed on the graphene surface that cause the pore blockage, it is possible to wash them away from the graphene surface (with or without added chemicals). For the pore clogging by larger molecules (such as N 2 ), it is possible to blow air backwards (pure H 2 O, H 2 or CO 2 ), to dislodge the larger molecule and unclog the pore. Fig.6 shows an embodiment of a cylindrical device with zig-zag surface to allow more pores for CO 2 to go through. [0054] An aspect of the flow rate for the crown pore in graphene is further described below. It may be shown that the crown pore graphene has a much higher permeance than those other membranes currently in use. In an aspect, an amount of crown-pore-containing graphene to filter the CO 2 from a coal power plant operating at 1 Giga Watt can be determined.
[0055] An example of a fabrication process can be as follows. Graphene supported by a porous substrate can be obtained, e.g., purchased. Then ion-beam-sculpting and subsequently enlargement by oxidative etching can be used to make crown pores in graphene. For example, ions can be accelerated toward the graphene to make holes in it, which subsequently react with oxygen in an oxidative etching step to make crown pores in graphene. The resulting crown pore can be fully oxidized and can be stable when being used to separate CO 2 from the flue gas. Fig. 8 is a flow diagram illustrating a fabrication process in an embodiment. At 802, ion-beam-sculpting is caused on a graphene sheet, which can be supported by a porous substrate. For example, ion perforation can be caused on a graphene sheet, which can be supported by a porous substrate. At 804, oxidative etching can be performed, which can enlarge pores. Carbon atoms exposed at the edges of the pores can be bonded with another element such as oxygen.
[0056] In an embodiment, defects (e.g., larger pores) in graphene, which may yield a lower selectivity, can be corrected or solved by applying multiple filters in series, to increase the purity of the final CO 2 . For example, if the selectivity (CO 2 /N 2 ) is 95% and the input gas mixture has the ratio N2:CO 2 =10: 1 , after going through the first filter the ratio becomes 0.5263:1. Further sending this mixture through a second filter makes the ratio only 0.0277:1, suggesting that CO 2 is 97.23% pure.
[0057] Carbon capture can make considerable contribution to greener environment. For instance, since the beginning of the industrial revolution, large amounts of CO 2 have been put into the atmosphere. Existing membrane filters may have either a low permeance or a low selectivity for CO 2 . In an aspect of separating CO 2 from flue gas, the functional group on the edge of a pore in graphene should not be oxidized because that would make it unstable to chemical reactions. In an embodiment, oxygen-terminated crown pores in graphene disclosed herein do not oxidize further and are therefore stable. Due to its chemical bonding, the oxygen-terminated crown pore is chemically inert, therefore it is suitable for the flue gas environment (containing O 2 and with a high temperature).
[0058] Fig. 9 is a flow diagram illustrating a method of capturing carbon dioxide in an embodiment. At 902, carbon dioxide can be filtered from flue gas using graphene having pores tipped with another element. An example of another element can be oxygen. Another example can be nitrogen. Carbon dioxide in the flue gas is caused to enter or caused to be transported to an area of a second side of the graphene via at least one of the pores, for example, as described with reference to Fig.5. In an embodiment, the method can also include applying higher pressure in the area of the first side than in the area of the second side. The method can also include using a first membrane filter as a first stage filter before using the graphene as a second stage filter. [0059] In an embodiment, CO 2 from N 2 can be filtered using an unstretched graphene crown pore (CP) tipped with oxygen (O-CP). In an embodiment, CO 2 can be filtered from N 2 using an O-CP isotropically stretched by about 1.0%. In an embodiment, graphene with oxygen CPs can be placed on a porous substrate for support against driving pressure. For example, graphene with CPs can be placed directly on a porous substrate. In an embodiment, CO 2 permeance can be improved by stretching graphene more to open the O-CP more. An embodiment allows pressure-swing pumping of CO 2 through the O-CP membrane in which the positive flow rate is high at high pressure and the (unwanted) negative flow from backsplash is low at low pressure. In an embodiment, H2 and H2O can be filtered from other gas using a graphene O-CP. In another embodiment, crushed or spin-cast O-CP graphene can be placed into an irregular mesh to filter CO 2 from N 2 . In an embodiment, an interlocked multi- layered structure with O-CP graphene or O-CP graphene flakes can be used to allow a large pressure difference (e.g., 100 bar) to more quickly filter CO 2 from N 2 . In another embodiment with high CO 2 /N 2 selectivity, graphene crown pores tipped with nitrogen can be used. Another embodiment with high molecular selectivity can include using the Coulomb force exerted by graphene crown-like pores tipped with atoms other than oxygen and nitrogen that have an electronic charge as a result of their binding with the graphene. In an embodiment, a cylindrical device with a zig-zag membrane on the surface can be provided which permits more pores for CO 2 to enter from the outside (e.g., high pressure) to the inside (e.g., low pressure) of the cylinder. For example, the outside and the inside can have different pressures. For instance, the high pressure part of this zig zag pattern can be either inside or outside the graphene zig zag. For instance, the center of the zig zag can be lower pressure than the outside region, or the other way too, for example, the center of the zig zag can be higher pressure than the outside. Generally, for example, there can be some pressure difference between the inside and the outside regions. An embodiment can include an application of a two-stage filter where a low-selectivity conventional membrane filter is used before the high-selectivity graphene crown pore filter. An embodiment can include an application of several graphene crown pore filters in series to improve the total CO 2 purity. [0060] Mass Flux through the Crown Pores [0061] By way of example, this discussion calculates the flow rate of CO 2 per unit area through crown pore graphene and estimates the total area needed to capture the CO 2 from a GigaWatt power plant burning coal. It also calculates the permeance, which is the flow rate per unit pressure difference, measured in units of 10 - 10 moles m -2 s -1 Pa -1 .
[0062] Consider the kinetic theory of gases, where the flux of molecules through a surface is J = nv m /4 where v m is the mean thermal speed, (8k B T/πm) 0.5 for Boltzmann constant k B = 1.38 x 10 -16 erg K -1 , mass m of the molecule, temperature T, and density n. With molecules on both sides of the surface going in each direction, J = Δn s v m /4 where Δn s = n 2 — n o is the difference in select gas density on the two sides, subscript 2 indicating the flue gas side of the membrane while n o is the density of the same molecule outside. The total density on the flue gas side is denoted by n, so for a select molecule that is a fraction f of the total number of molecules on the flue gas side, n 2 = fn and J = (fn — n o )v m /4.
[0063] First find the density of all molecules at Standard Temperature and Pressure (STP). For example, use the perfect gas law, P = nk B T where P = 1.01 x 10 6 dyn/cm 2 at STP and T = 273.15K. This gives a total density n = 2.68 x 10 19 cm -3 .
[0064] The mean thermal speed of CO 2 is v m = 3.61 x 10 4 cm/s at STP for mean molecular weight equal to (12 + 2 x 16) x 1.67 x 10 -24 grams = 7.35 x 10 -23 grams. Let Δn s = nΔP s /P for relative partial pressure difference of the select gas, ΔP S /P. The two sides of the filter are assumed to be at the same temperature, so ΔP S = (n 2 - n 0 )k B T. For high pressures on the flue gas side, n 2 >> n o , in which case ΔP S /P ≈ fΔP/P where ΔP/P >> 1 is the compression factor.
[0065] These equations give the flux through a surface equal to
J = 0.25nv m fΔP/P = 2.42 x 10 23 f(ΔP/P) (1) at STP in units of molecules per second per square cm.
[0066] Now convert this number flux to a mass flux F by multiplying J by the mean mass per CO2 molecule, which from above is 7.35 x 10 -23 grams. The result is F = 17.8f(ΔP/P) grams cm -2 s -1 .
[0067] This is for an open surface. Multiply this by the fraction of the area of the graphene that is covered by crown pores, assuming each pore is a hole like this. The density of crown pores can be as high as 10 12 cm -2 , and the size of a pore is 0.05 nm 2 = 5 x 10 -16 cm 2 . Considering an uncertainty factor e that is either larger than 1 if there is an attractive force to the hole or smaller than 1 if the CO 2 alignment and orientation has to be more precise than in the kinetic theory, the fraction of the area covered by the holes is n = 5 x 10 -4 ∈. [0068] Then the mass flux through the crown pores is approximately
F = 17.8 - nf(ΔP/P) = 8.9 x 10 3 ∈f (ΔP/P) g cm -2 s -1 . (2)
[0069] The permeance is the flux in units of moles per unit area and time, per unit pressure difference. The same starting point is J = Δnv m /4 for density difference An and thermal speed v m . For one Pascal of pressure difference, ΔP 1 = 10 dy cm -2 , the density difference is Δn = ΔP 1 /k B T = 2.65 x 10 14 ΔP 1 cm -3 for T = 273.15 K. Multiplying this by v m /4 gives J = 2.39 x 10 18 molecules cm -2 s -1 Pa -1 , and dividing the result by Avogadro's number gives J = 4.0 x 10 -6 moles cm -2 s -1 Pa -1 . Considering now the fraction of the area that has a crown pore, = 5 x 10 -4 ∈, the permeance for CO 2 in crown pore graphene is the product of these, Jcrown pore = 2 x 10 -9 ∈ moles cm -2 s -1 Pa -1 . In units of m -2 , this is J crown pore = 2 x 10 -5 ∈ moles m -2 s- 1 Pa -1 . In common units of 10 -10 moles m -2 s -1 Pa -1 , this is a permeance of 2.0 x 10 5 ∈.
[0070] This permeance is much larger than other known membranes such as the hollow fiber cellulose triacetate membranes, an asymmetric hollow fibre membrane and other known systems. The crown pore graphene disclosed herein has a much higher permeance than these other membranes currently in use. This implies a much smaller membrane area is needed, by the inverse of the permeance.
[0071] Area needed to Capture CO 2 from a GW Coal Power Plant
[0072] Now calculate graphene area at the above crown pore density to filter the CO 2 from a coal power plant operating at 1 Giga Watt, which serves as a reference point.
[0073] According to the EIA (https colon slash slash (://) www dot (.) eia dot (.) gov slash (/) tools slash (/) faqs slash (/) faq dot (.) php?id7- 4&t1 -1), coal in the United States of America produces 9.48 x 10 11 kWh of electricity and puts out 9.52 x 10 8 metric tons of CO 2 . This implies that 1 GWh puts out 1.018 x 10 9 g CO 2 from coal burning. Dividing this by the number of seconds in an hour suggests that 1 GW puts out 2.83 x 10 5 g CO 2 s -1 .
[0074] Now estimate the area A of crown pore graphene needed to filter this CO 2 rate. Equate the product of the flux per unit area times the area, FA, to the emission rate of CO 2 : FA = 2.83 x 10 5 g s -1 , where F =
8.9 x 10 -3 ∈f(ΔP/P) g cm -2 s -1 . This gives A = 3.18 x 10 3 / (∈f ΔP / P) m 2 . With f = 0.2 for the CO 2 fraction of molecules in flue gas and ΔP/P = 50 for the average compression factor above atmospheric pressure, A = 318/∈ m 2 . Scaled to the power output S of the coal power plant, A = 318S/∈ m 2 for S in GW. Recall that ∈ is a correction factor to convert the perfect gas equations for flux through a hole to the actual flux for CO 2 through a crown pore graphene membrane.
[0075] Natural gas emits less CO 2 per GW. According to the EIA again, natural gas produces 1.36 x 10 12 kWh in the USA and produces 5.6 x 10 14 grams of CO 2 . This is 1.14 x 10 5 g CO 2 s -1 for a GW, compared to
2.83 x 10 5 g CO2 s -1 for coal. The ratio is 0.41. Applying this ratio to the required graphene area, we get 129/∈ m 2 for a GW powered by natural gas.
[0076] The result is ~ 320 m 2 for a GW of coal power and ~ 130 m 2 for a GW of gas power, divided by the correction factor ∈ . Typical membrane areas for a GW power plant from known examples can belO 3 times larger, on the order of several times 10 5 m 2 , because the permeance of the membranes considered there are around 10 3 times lower.
[0077] According to Carbon Brief (https colon slash slash (://) www dot (.) carbonbrief dot (.) org slash (/) mapped- worlds-coal-power-plants), there is 2.045 TW of coal-fired power in the world. That corresponds to a need for ~
6.5 x 10 5 m 2 of crown pore graphene, or 0.65 square kilometer. According to Forbes (https colon slash slash (://) www dot (.) forbes dot (.) com slash (/) sites slash (/) judeclemente slash (/) 2019 slash (/) 12 slash (/) 15 slash (/) global-natural-gas-electricity-is-gaining-on-coal slash (/) ?sh=61ecdb407bfd), there is 1.7 TW of gas-fired power in the world. That corresponds to an additional need for ~ 2.1 x 10 5 m 2 of crown pore graphene, or 0.21 square kilometer. The sum of these needs is 0.86 square km. According to ACS Material (https colon slash slash (://) www dot (.) acsmaterial dot (.) com slash (/) graphene-facts), one square meter of graphene weighs 0.77 milligrams, so 0.86 square km weighs 0.66 kg.
[0078] In an aspect, all of the CO 2 emission by power plants in the world may be captured by about one kilogram of crown pore graphene.
[0079] Two stage filtering
[0080] Crown pore graphene can be a filter for CO 2 that can have a very high selectivity over N 2 . The amount of crown pore graphene can be reduced if another membrane with less selectivity filters the flue gas as a first step, passing the result with a high CO 2 fraction to crown pore graphene for a second filtering to make the CO 2 fraction even higher. [0081] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “or” is an inclusive operator and can mean “and/or”, unless the context explicitly or clearly indicates otherwise. It will be further understood that the terms “comprise”, “comprises”, “comprising”, “include”, “includes”, “including”, and/or “having,” when used herein, can specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the phrase “in an embodiment” does not necessarily refer to the same embodiment, although it may. As used herein, the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. As used herein, the phrase “in another embodiment” does not necessarily refer to a different embodiment, although it may. Further, embodiments and/or components of embodiments can be freely combined with each other unless they are mutually exclusive. [0082] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements, if any, in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.