Relevant bibliographies by topics / Mixed reactant

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Mixed reactant'

Author: Grafiati
Published: 4 June 2021
Last updated: 9 February 2022

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Journal articles on the topic "Mixed reactant"

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Comyns, Alan E. "Mixed reactant fuel cells." Focus on Catalysts 2007, no. 5 (May 2007): 1. http://dx.doi.org/10.1016/s1351-4180(07)70248-9.

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Priestnall, Michael A., Vega P. Kotzeva, Deborah J. Fish, and Eva M. Nilsson. "Compact mixed-reactant fuel cells." Journal of Power Sources 106, no. 1-2 (April 2002): 21–30. http://dx.doi.org/10.1016/s0378-7753(01)01068-0.

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Shukla, A. K., R. K. Raman, and K. Scott. "Advances in Mixed-Reactant Fuel Cells." Fuel Cells 5, no. 4 (December 2005): 436–47. http://dx.doi.org/10.1002/fuce.200400075.

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Riess, Ilan. "Selectivity and mixed reactant fuel cells." Functional Materials Letters 08, no. 04 (August 2015): 1540010. http://dx.doi.org/10.1142/s179360471540010x.

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Mixed reactant fuel cells (MR-FCs), are aimed at using a uniform mixture of fuel and oxygen applied to both the anode and the cathode. This allows redesign of fuel cells with a significantly simpler construction, having potentially a higher power density, better fuel utilization and be less expensive. The challenge in realizing MR-FCs is finding selective electrodes that can enhance oxygen reduction at the cathode, fuel oxidation at the anode while inhibiting the chemical reaction between the fuel and oxygen in the gas mixture. This task is in particular challenging in solid oxide fuel cells (SOFCs), as they operate at elevated temperatures, where many reactions are easily activated and selectivity is difficult to achieve. As a result no true MR-FC of the SOFC type were reported while some were found for low temperature fuel cells (FCs). The so-called single-chamber-SOFC are not true MR-FCs as they do not contain two selective electrodes, as required. We shall discuss potential ways to search for and develop selective anodes and cathodes for SOFC type MR-FCs. We first consider material properties which should contribute to that goal. This refers to electronic properties of the bulk, band banding under adsorbed specie, point defects in the bulk and on the surface. We then proceed to show how cell design, in particular electrode structure, can contribute to selectivity. Finally operation conditions are considered and it is shown that they also can contribute to selectivity. The operation condition considered are gas mixture composition, gas mixture residence time in the hot zone, hence gas flow rate, current density and temperature. The topics discussed hold for all FC types but are crucial for the SOFC type because of the difficulty to achieve selectivity at elevated temperatures. It is suggested that a concerted effort taking advantage of all those options should allow development of a true SOFC type MR-FC.
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WATANABE, TOMOAKI, YASUHIKO SAKAI, KOUJI NAGATA, OSAMU TERASHIMA, HIROKI SUZUKI, TOSHIYUKI HAYASE, and YASUMASA ITO. "VISUALIZATION OF TURBULENT REACTIVE JET BY USING DIRECT NUMERICAL SIMULATION." International Journal of Modeling, Simulation, and Scientific Computing 04, supp01 (August 2013): 1341001. http://dx.doi.org/10.1142/s1793962313410018.

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Direct numerical simulation (DNS) of turbulent planar jet with a second-order chemical reaction (A + B → R) is performed to investigate the processes of mixing and chemical reactions in spatially developing turbulent free shear flows. Reactant A is premixed into the jet flow, and reactant B is premixed into the ambient flow. DNS is performed at three different Damköhler numbers (Da = 0.1,1, and 10). Damköhler number is a ratio of a time scale of a flow to that of chemical reactions, and in this study, the large Da means a fast chemical reaction, and the small Da means a slow chemical reaction. The visualization of velocity field shows that the jet flow is developed by entraining the ambient fluid. The visualization of concentration of reactant A shows that concentration of reactant A for Da = 1 and 10 becomes very small in the downstream region because the chemical reaction consumes the reactants and reactant A is diffused with the jet development. By comparison of the profiles of chemical reaction rate and concentration of product R, it is found that product R for Da = 10 is produced by the chemical reaction at the interface between the jet and the ambient fluids and is diffused into the jet flow, whereas product R for Da = 0.1 is produced in the jet flow after reactants A and B are well mixed.
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Riess, Ilan. "Selective Electrodes for Mixed Reactant Fuel Cells." ECS Transactions 77, no. 10 (May 3, 2017): 111–15. http://dx.doi.org/10.1149/07710.0111ecst.

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RIESS, ILAN. "CATALYTIC REQUIREMENTS FOR MIXED REACTANT FUEL CELLS." Functional Materials Letters 01, no. 02 (September 2008): 105–13. http://dx.doi.org/10.1142/s1793604708000198.

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Significant advantage could be achieved if mixed reactant fuel cells, MR-FC, were functioning. These cells are intended to operate on a mixture of air and fuel introduced into both the cathode and anode compartment. Symmetry is broken by using different electrode materials exhibiting special and different catalytic properties. No high temperature fuel cell was reported to date to function as a true MR-FC and only one, low temperature type, did function properly. We discuss the required catalytic properties which are unique in that they promote electrochemical reactions and suppress chemical ones as well as possible ways to search for them. The chemical reaction which has to be suppressed is the direct reaction of fuel and oxygen as the two components are premixed and the mixture is then introduced into the fuel cell at both electrode compartments. The electrochemical reactions that should be promoted are the reduction of oxygen at the cathode and the oxidation of fuel at the anode only by oxygen ions that emerge from the solid electrolyte. Conditions to promote this selectivity are discussed. These are derived from the theory of chemisorption as applied to heterogeneous catalysis.
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Barton, S. Calabrese, T. Patterson, E. Wang, T. F. Fuller, and A. C. West. "Mixed-reactant, strip-cell direct methanol fuel cells." Journal of Power Sources 96, no. 2 (June 2001): 329–36. http://dx.doi.org/10.1016/s0378-7753(00)00663-7.

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Barton, S. C. "Mixed-reactant, strip-cell direct methanol fuel cells." Fuel and Energy Abstracts 43, no. 4 (July 2002): 262. http://dx.doi.org/10.1016/s0140-6701(02)86300-7.

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TURCHI, C. "Mixed reactant photocatalysis: Intermediates and mutual rate inhibition." Journal of Catalysis 119, no. 2 (October 1989): 483–96. http://dx.doi.org/10.1016/0021-9517(89)90176-0.

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Dissertations / Theses on the topic "Mixed reactant"

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Aziznia, Amin. "Development of a Swiss-roll mixed-reactant fuel cell." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45737.

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Capital and operating costs of fuel cell systems must be reduced before they can be competitive with conventional energy conversion technologies. This dissertation concerns the development of an unconventional fuel cell aimed at meeting that challenge. Presented here, for the first time, is a novel cylindrical Swiss-roll mixed-reactant fuel cell (SR-MRFC) that eliminates expensive and failure-prone components of conventional fuel cells. The proof-of-concept of the SR-MRFC was performed both in monopolar and bipolar architectures. In the monopolar case 3D anodes with platinum or with osmium catalysts were coupled to a gas-diffusion MnO₂ cathode in a 20×10-⁴ m² single-cell SR-MRFC, operated with a two-phase mixture of 1 M NaBH₄/2M NaOH(aq) + O₂(g). Instead of a Nafion® membrane, a porous diaphragm was employed. At 323 K, 105 kPa(abs), the peak superficial power densities of the SR-MRFC with the platinum and osmium anode catalysts were up to respectively 2230 and 1880 W m−² with good performance stability during 3 hr continuous operation. These values are the highest power densities ever reported for MRFCs operating under similar conditions and match the highest reported values for conventional dual chamber PEM direct borohydride fuel cells. Scale up of the single-cell SR-MRFC to 100×10-⁴ m² and 200×10-⁴ m² gave corresponding peak superficial power densities of 900 and 700 W m-², while the 20×10-4 m² bipolar reactors produced peak volumetric power densities of 267 and 205 kW m-³. This work also explored the feasibility of electroreduction of N₂O on Pt and Pd in the cathode of a MRFC to generate electricity from N₂O in the tail gases of industrial processes. Here the SR-MRFC was operated using two-phase fuel + oxidant mixtures of 1 M NaBH₄ / 2M NaOH(aq) + N₂O(g) and 0.5 M CH₃OH/2 M NaOH(aq) + N₂O(g). At 323 K, 105 kPa(abs) the peak superficial power densities for the mixed NaBH₄- and MeOH-N₂O systems were respectively 340 W m-² (Pt anode/Pd cathode) and 38 W m-² (PtRu anode/Pd cathode). This work demonstrates for the first time that co-generation of electricity and abatement of N₂O may potentially compete with thermochemical processes of N₂O capture currently under development.
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Liedhegner, Joseph Edward. "RADIOLYTICALLY POWERED MICRO FUEL CELL." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1200158754.

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TOKEKAR, DEVKINANDAN MADHUKAR. "MODELING AND SIMULATION OF REACTING FLOWS IN LEAN-PREMIXED SWIRL-STABLIZED GAS TURBINE COMBUSTOR." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141412599.

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London, Thomas G. (Thomas Gérard). "Design and testing of a lobed mixer for the study of mixing enhancement in reacting flows." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/47393.

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Machaba, Mashudu Innocent. "Unsteady hydromagnetic chemically reacting mixed convection MHD flow over a permeable stretching sheet embedded in a porous medium with thermal radiation and heat source/sink." Diss., 2018. http://hdl.handle.net/11602/1124.

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MSc (Mathematics)
Department of Mathematics and Applied Mathematics
The unsteady hydromagnetic chemically reacting mixed convection MHD ow over a permeable stretching sheet embedded in a porous medium with thermal radiation and heat source/sink is investigated numerically. The original partial di erential equations are converted into ordinary di erential equations by using similarity transformation. The governing non-linear partial di erential equations of Momentum, Energy, and Concentration are considered in this study. The e ects of various physical parameters on the velocity, temperature, and species concentration have been discussed. The parameters include the Prandtl number (Pr), Magnetic parameter (M), the Schmidt number (Sc), Unsteady parameter (A), buoyancy forces ratio parameter (N), Chemical reaction (K), Radiation parameter (Nr), Eckert number (Ec), local heat source/sink parameter (Q) and buoyancy parameter due to temperature ( ). The coe cient of Skin friction and Heat transfer are investigated. The coupled non-linear partial di erential equations governing the ow eld have been solved numerically using the Spectral Relaxation Method (SRM). The results that are obtained in this study are then presented in tabular forms and on graphs and the observations are discussed.
NRF
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Books on the topic "Mixed reactant"

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Center, Lewis Research, and United States. Dept. of Energy. Division of Energy Storage Systems, eds. Evaluation of developmental membranes for the mixed reactant iron -chromium redox system. [Cleveland, Ohio: National Aeronautics and Space Administration, Lewis Research Center, 1985.

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Book chapters on the topic "Mixed reactant"

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Guzmán, Adolfo, Carmen Domínguez, and Jesús Olivares. "Reacting to Unexpected Events and Communicating in Spite of Mixed Ontologies." In MICAI 2002: Advances in Artificial Intelligence, 377–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-46016-0_40.

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Jawalkar, Swapna, Odelu Ojjela, and Debasish Pradhan. "Influence of Thermophoresis and Brownian Motion on MHD Mixed Convective Chemically Reacting Couple Stress Fluid Flow in Porous Medium Between Parallel Plates." In Mathematical Modeling and Computational Tools, 51–69. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3615-1_4.

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Priestnall, Michael A., Vega P. Kotzeva, Deborah J. Fish, and Eva M. Nilsson. "Compact mixed-reactant fuel cells." In Fuel Cells Compendium, 593–606. Elsevier, 2005. http://dx.doi.org/10.1016/b978-008044696-7/50065-9.

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Doraiswamy, L. K. "Reactor Design for Simple Reactions." In Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.003.0017.

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Ideal reactors and their design principles were discussed in Chapter 4. In addition to these ideal reactors, there are certain reactors in which a reasonably welldefined measure of mixing can be introduced. These are the recycle plug-flow reactor and a sequence of fully mixed reactors. Many organic reactions are conducted in a stirred reactor containing a batch of the same or a second reactant, and continuously feeding, or withdrawing, or feeding and withdrawing one or more of the reactants and/or products. These are referred to as semibatch reactors. They belong to a more general class of reactors known as variable volume reactors. The design of all of these types of reactors is briefly considered in this chapter. The principle of the recycle-flow reactor (RFR) is sketched in Figure 10.1.
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Bethke, Craig M. "Mass Transfer." In Geochemical Reaction Modeling. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195094756.003.0015.

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In previous chapters we have discussed the nature of the equilibrium state in geochemical systems: how we can define it mathematically, what numerical methods we can use to solve for it, and what it means conceptually. With this chapter we begin to consider questions of process rather than state. How does a fluid respond to changes in composition as minerals dissolve into it, or as it mixes with other fluids? How does a fluid evolve in response to changing temperature or variations in the fugacity of a coexisting gas? In short, we begin to consider reaction modeling. In this chapter we consider how to construct reactions paths that account for the effects of simple reactants, a name given to reactants that are added to or removed from a system at constant rates. We take on other types of mass transfer in later chapters. Chapter 12 treats the mass transfer implicit in setting a species’ activity or gas’ fugacity over a reaction path. In Chapter 14 we develop reaction models in which the rates of mineral precipitation and dissolution are governed by kinetic rate laws. Simple reactants are those added to (or removed from) the system at constant rates over the reaction path. As noted in Chapter 2, we commonly refer to such a path as a titration model, because at each step in the process, much like in a laboratory titration, the model adds an aliquot of reactant mass to the system. Each reactant Ar is added at a rate nr, expressed in moles per unit reaction progress, ξ. Negative values of nr, of course, describe the removal rather than the addition of the reactant. Since ξ is unitless and varies from zero at the start of the path to one at the end, we can just as well think of nr as the number of moles of the reactant to be added over the reaction path. A simple reactant may be an aqueous species (including water), a mineral, a gas, or any entity of known composition.
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Doraiswamy, L. K. "Mixing, Multiple Solutions, and Forced Unsteady-State Operation." In Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.003.0020.

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Three important (complicating) possibilities were not considered in the treatment of reactors presented in earlier chapters: (1) the residence time of the reactant molecules need not always be fully defined in terms of plug flow or fully mixed flow; (2) the equations describing certain situations can have more than one solution, leading to multiple steady states; and (3) there could be periods of unsteady-state operation with detrimental effects on performance, that is, transients could develop in a reactor. Actually, reactors can operate under conditions where there is an arbitrary distribution of residence times, leading to different degrees of mixing with consequent effects on reactor performance. Also, multiple solutions do exist for equations describing certain situations, and they can have an important bearing on the choice of operating conditions. And, finally, unsteady-state operation is a known feature of the start-up and shutdown periods of continuous reactor operation; it can also be introduced by intentional cycling of reactants. We briefly review these three important aspects of reactors in this chapter. However, because the subjects are highly mathematical, the treatment will be restricted to simple formulations and qualitative discussions that can act as guidelines in predicting reactor performance. All aspects of mixing in chemical reactors are based on the theory of residence time distribution first enunciated by Danckwerts (1953). Therefore, we begin our discussion of mixing with a brief description of this theory. When a steady stream of fluid flows through a vessel, different elements of the fluid spend different amounts of time within it. This distribution of residence times is denoted by a curve which represents, at any given time, the amount of fluid with ages between t and t + dt flowing out in the exit stream.
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Kofstad, Per, and Rune Bredesen. "ON THE USE OF THE WAGNER MODEL IN OXIDATION IN MIXED REACTANTS." In High Temperature Corrosion of Advanced Materials and Protective Coatings, 3–12. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-88970-6.50006-3.

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Steger, Manfred B., and Ravi K. Roy. "5. Neoliberalism challenged." In Neoliberalism: A Very Short Introduction, 100–128. Oxford University Press, 2021. http://dx.doi.org/10.1093/actrade/9780198849674.003.0005.

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‘Neoliberalism challenged’ studies the challenges to neoliberalism in the 21st century. The most serious challenge to the dominant neoliberal framework occurred in 2008, when the collapse of the American over-valued real-estate market triggered the global financial crisis. Reacting to rising economic and cultural tensions in a globalizing world, nationalist forces on the political Right were also gathering strength in the 2010s. National populists blamed neoliberal globalization for economic decline and cultural decay. To get a better sense of the nature of national populism's challenge to neoliberalism, the mixed ideological and policy framework of Trumpism should be looked at. What is the future for neoliberalism?
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Anderson, Greg M., and David A. Crerar. "Ideal Solutions." In Thermodynamics in Geochemistry. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195064643.003.0014.

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The chemical constituents of a solution can be varied — added, subtracted and interchanged or substituted for each other — within limits ranging from complete (e.g., gases) to highly restricted (trace components in quartz). Adding or subtracting chemical constituents to or from a phase involves changes in energy, which will be discussed in the following sections. For example, if two components A and B are mixed together, the Gibbs energy of a solution of the two mixed must be less than the sum of the Gibbs energies of the two separately for the spontaneous reaction to take place. That is, if we mix nA moles of component A and nA moles of component B, their combined total G is (nAGA + nBGB) where GA and GB are the molar free energies of A and B. If G(A,B) is the total free energy of the resulting solution, then necessarily if the solution took place spontaneously. Alternatively, dividing through by nA + nB, where XA and XB are the mole fractions. Thus if A is albite and B is anorthite, then (A,B) is plagioclase, and we say that the plagioclase solid solution is more stable than a "mechanical mixture" of grains of albite and anorthite. On the other hand if A is diopside and B is anorthite, little or no mutual solution takes place because in this case so that no spontaneous solution reaction takes place. The term "mechanical mixture" in this context nicely conveys the idea of quantities of mineral grains mixed together and not reacting, but does not work quite so well if A and B are other things such as water and halite, or water and alcohol. Nevertheless, the term is traditionally used no matter what the nature of the solution constituents, and no harm is done as long as we remember that "mechanical mixture" means that the constituents considered do not react with each other, whatever their physical nature.
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Anderson, Greg M., and David A. Crerar. "Fugacity and Activity." In Thermodynamics in Geochemistry. Oxford University Press, 1993. http://dx.doi.org/10.1093/oso/9780195064643.003.0015.

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In Chapter 7 we saw that the fact that minerals are to a good approximation incompressible means that the effect of pressure on the Gibbs free energy of solid phases is very easily calculated. Thus, in general and, because V for solids can often be considered independent of P, This, combined with the more complex integration of dG over a temperature interval at one bar pressure, allowed us to calculate the position of phase boundaries at high pressures and temperatures. The next question is how to evaluate the pressure integral (11.1) when a fluid such as H2O or CO2 is involved, either in the pure form, mixed with other fluid components, or reacting with solid phases? Obviously, assuming that the molar volume of a fluid is a constant is not even approximately true, and is unacceptable. A possible way to proceed would be to express V as a function of P in some sort of power series, just as we did for Cp as a function of T (equation 7.12). VdP could then be integrated, and we could determine the values of the power series coefficients for each gas or fluid and tabulate them as we do for the Maier-Kelley coefficients. Fortunately, thanks to the insight of G.N. Lewis, we can proceed in a simpler and completely different fashion. Lewis in 1901 defined a new function, the fugacity, which can be thought of as a kind of idealized or thermodynamic pressure, which expresses the value of ʃ V dP single-handedly.
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Conference papers on the topic "Mixed reactant"

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Ardis, Paul A., Nenad G. Nenadic, Mark R. Walluk, and Daniel F. Smith. "Forecasting Reactant Ignition in Solid Oxide Fuel Cell Systems." In ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2012 6th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fuelcell2012-91014.

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Solid oxide fuel cell electrochemical stacks require high quality reformate for performance and durability. Insufficiently mixed reactants, carbon deposits, or improper chemical ratios thereof can result in reactant ignition during mixing prior to catalysis. Reactant ignition can warp and plug downstream components; therefore, it is desirable to predict and mitigate reactant ignition. Leading machine learning techniques were applied to the task of predicting ignition events in prototype (diesel-fueled) solid oxide fuel cells at a 30-second event horizon, using both current signal state and up to 30 seconds of signal history to make predictions. Based upon our analysis, first-order particle filtering using Fisher discriminant meta-reasoning provided the best cross-system performance when compared to other meta-reasoning methods (e.g., logistic regression, kernel support vector machine) as well as traditional vector quantization. In this paper, we demonstrate particle filter construction using data from eleven sensors, analyze predictive performance on real-world data, and discuss modifications to handle further system design changes.
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D'Angelo, A., F. Gilardoni, V. Toschi, C. Ciminiello, E. A. Sinico, and S. Viganò D'Angelo. "REDUCED PROTEIN S ANTICOAGULANT ACTIVITY IN ESSENTIAL MIXED CRYOGLOBULINEMIA." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644293.

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Protein S (PS) is found in two forms in plasma, as free PS, which functions as a cofactor for activated protein C, and in e-quimolar complex with C4b-binding protein (C4b-bp), an inhibitor of the complement system. The Kd of the PS-C4b-bp interaction is one order of magnitude lower than the plasma concentration of the two proteins; thus 55-60% of total PS circulates in the bound form. Evidence has been provided that in vitro complement activation does not affect the equilibrium between PS and C4b-bp; however in patients with systemic lupus erythematosus and low C4 levels, a shift from free to bound PS has been observed. To further evaluate the relationship between complement activation and PS distribution we have measured PS and C4b-bp levels in 21 patients with essential mixed cryoglobulinemia (EMC), an autoimmune disorder characterized by cryo-precitable circulating immunocomplexes and associated with vasculitis and thrombotic episodes. EMC patients had cryocrit rangin from 1 to 66% and greatly reduced complement components (Clq: 45%, C3: 71%, C4: 15% of normal). Mean PS activity was significantly reduced inpatients as compared to the control population consisting of 20 age-and sex-matched blood donors (69%, p< 0.001). Free PS was similar in patients and controls, but total PS was lower in EMC patients (82%, p<0.05). Seven EMC patients had C4b-bp levels be low 60%. Thus, reduction of PS activity in patients with EMC is not due to reduced free PS. Cultured endothelial cells synthesize and release PS with reduced specif ic activity. In EMC patients very high levels of von Willebrand factor (313%, p< 0.001) a protein released from endothelial cells, but not of ceruplasmin, another acute phase reactant protein, were observed.In vivo release of PS from en dothelial cells might contribute to reduced PS specific activity in EMC.
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Diver, Richard B., James E. Miller, Mark D. Allendorf, Nathan P. Siegel, and Roy E. Hogan. "Solar Thermochemical Water-Splitting Ferrite-Cycle Heat Engines." In ASME 2006 International Solar Energy Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/isec2006-99147.

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Thermochemical cycles are a type of heat engine that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibilities of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). These concepts utilize two sets of moving beds of ferrite reactant material in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency – thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this paper, the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine concept is introduced and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our results and development approach are also outlined.
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Andreassi, Luca, Stefano Cordiner, Massimo Feola, and Fabio Romanelli. "Development and Experimental Validation of a Simulation Tool for a Fuel Cell Based Power System." In ASME 7th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2004. http://dx.doi.org/10.1115/esda2004-58276.

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Fuel cells (FC) technology applied to energy production could represent an effective solution to face greenhouse gas emissions and to differentiate energy sources. However, real performances of FC systems still represent a critical issue in the definition of an assessed and economically competitive technology. In fact, FC performances depend on many variables such as temperature, pressure, current, membrane humidification, stoichiometry of the reactant gas, etc.; additionally, many of these influencing parameters depend one on the other, further complicating the analysis. Numerical simulation could greatly contribute to a better understanding of the influence of design parameters. Nevertheless, the availability of experimental data to validate and to verify the numerical models is an imperative issue. The primary target of the research activity described in this paper is the set up of an experimental test bench for Proton Exchange Membrane Fuel Cell (PEM FC) at the Department of Mechanical Engineer of the University of Roma Tor Vergata aiming to completely test 8 cells 0.1 kW stack: the measured data are fundamental to validate the numerical models which have been developed by the Authors following different hierarchical levels (both semi-empirical and dimensional analytical approach) with different predictive capabilities. This apparatus allows the control of the reactant gas mass flow rates, stack pressure, humidity, current, temperature and voltage. In this way it is possible to assess a mixed experimental-numerical methodology allowing a tuning procedure for the developed models making a wide use of dedicated experimental data. The preliminary results in terms of comparisons between experimental and computational data show a good agreement even by varying some of the most performance-affecting parameters such as operating pressure and temperature.
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Ganapathy, Harish, Sascha Steinmayer, Amir Shooshtari, Serguei Dessiatoun, Mohamed Alshehhi, and Michael M. Ohadi. "Enhanced Carbon Capture in a Multiport Microscale Absorber." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66345.

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Increasing concerns on the effects of global warming leading to climate change has necessitated the development of efficient technologies to separate acid gas components, such as carbon dioxide and hydrogen sulfide, from gaseous mixtures. Microscale technologies have the potential to substantially enhance gas-liquid absorption processes on account of their inherent high surface area to volume ratio. The present work reports the mass transfer characteristics during gas-liquid absorption in a multiport microscale absorber. The reactor was designed to comprise of 15 straight, parallel channels having a hydraulic diameter of 456 micrometer and square cross-sectional geometry. The absorption of CO2 mixed with N2 into aqueous diethanolamine was investigated. The performance of the absorber was characterized with respect to the absorption efficiency and mass transfer coefficient. Parametric studies investigating the effects of the gas and liquid phase superficial velocity were performed and discussed. Additionally, the effect of varying the liquid reactant concentration was investigated and discussed.
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Karalus, Megan F., K. Boyd Fackler, Igor V. Novosselov, John C. Kramlich, and Philip C. Malte. "Characterizing the Mechanism of Lean Blowout for a Recirculation-Stabilized Premixed Hydrogen Flame." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68060.

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The stability of hydrogen combustion under lean premixed conditions in a back-mixed jet-stirred reactor (JSR), is experimentally and numerically investigated. The goal is to understand the mechanism of flame extinction in this recirculation-stabilized flame environment. Extinction is achieved by holding the air flow rate constant and gradually decreasing the flow rate of the hydrogen fuel until a blowout event occurs. In order to gain insight on the mechanism controlling blowout, two dimensional computational fluid dynamic (CFD) simulations are carried out for the lean premixed combustion (LPM) of hydrogen as the fuel flow rate is reduced. The CFD model illustrates the evolution of the flow-field, temperature profiles, and flame structure within the JSR as blowout is approached. A single element chemical reactor network (CRN) consisting of a plug flow reactor (PFR) with recirculation is constructed based on the results of the CFD simulations, and its prediction of blowout is in good agreement with the experimental results. The chemical mechanism of Li et al. is used in both the CFD and CRN models, and GRI is used in the CRN for comparison. The modeling suggests that lean blowout does not occur with the flame in a spatially homogeneous condition, but rather under a zonal structure. Specifically, the flame is stabilized by the entrainment of combustion products from the re-circulation zone into the base of the reactant jet. The mixture of hot products and incoming premixed reactants proceeds through an ignition induction period followed by an ignition event. As the fuel flow decreases, the induction period increases and the ignition event is pushed further around the recirculation zone. Eventually, the induction period becomes so long that the ignition is incomplete at the point where the recirculating gas is entrained into the jet. This threshold leads to overall flame extinction.
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Marosky, A., V. Seidel, S. Bless, T. Sattelmayer, and F. Magni. "Impact of Cooling Air Injection on the Primary Combustion Zone of a Swirl Burner." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68898.

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In most dry low NOx combustor designs the front panel impingement cooling air is directly injected into the combustor primary zone. As this air partially mixes with the swirling flow of premixed reactants from the burner prior to completion of heat release it reduces the effective equivalence ratio in the flame and has a beneficial effect on NOx emissions. However, the fluctuations of the equivalence ratio in the flame potentially increase heat release fluctuations and influence flame stability. Since both effects are not yet fully understood isothermal experiments are made in a water channel where high speed planar laser induced fluorescence (HSPLIF) is applied to study the cooling air distribution and its fluctuations in the primary zone. In addition the flow field is measured with high speed particle image velocimetry (HSPIV). Both, mixing and flow field are also analyzed in numerical studies using isothermal large eddy simulation (LES) and the simulation results are compared with the experimental data. Of particular interest is the influence of the injection configuration and cooling air momentum variation on the cooling air penetration and dispersion. The spatial and temporal quality of mixing is quantified with probability density functions (PDF). Based on the results regarding the equivalence ratio fluctuations regions with potential negative effects on combustion stability are identified. The strongest fluctuations are observed in the outer shear layer of the swirling flow, which exerts a strong suction effect on the cooling air. Interestingly, the cooling air dilutes the recirculation zone of the swirling flow. In the reacting case this effect is expected to lead to a decrease of the temperature in the flame anchoring zone below the adiabatic flame temperature of the premixed reactant, which may have an adverse effect on flame stability.
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Auwaijan, Nicolas, and Vincent McDonell. "Investigating Boundary Layer Flashback of a High Turbulence Intensity Jet Flame at Gas Turbine Conditions." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15302.

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Abstract Hydrogen derived from non-fossil sources is an attractive candidate to replace carbon based fuels in gas turbines, as it is inherently carbon free. Yet the unusual combustion properties of hydrogen requires some care to successfully use it in gas turbines. To attain the lowest NOx emissions, uniformly low reaction temperatures must be assured thus the reactants must be well mixed. This is accomplished in low emission gas turbines by mixing the reactants within a pre-mixer section prior to entry into the combustor. With the addition of hydrogen into the fuel, certain issues arise such as higher flame speeds compared to carbon based fuels. Flashback is a phenomena that occurs when the flame no longer propagates beyond the exit of the premixer/injector but instead retracts and propagates upstream towards, and ultimately into the pre-mixer, causing significant damage due to such high temperatures. Flashback occurs when the flame speed exceeds either the local or bulk flow velocity. In practice, the question arises regarding the impact of turbulence levels. While an increase in turbulence intensity may help improve mixing, it also known to increase turbulent burning velocity. In the present work, the influence of bulk turbulence intensity of the flow on boundary layer flashback is investigated. Data are acquired for a different turbulence intensities at pressures from 3 to 8 bar with preheated reactants up to 750 deg. K. Various mixtures of hydrogen and methane are evaluated. The results show that even with significantly different bulk flow turbulence intensities (based on the ratio of flow centerline turbulence to centerline axial velocity) boundary layer flashback is not strongly affected. This is attributed to the role of the quenching distance in connection with damping within the boundary layer. It is noted that core flow flashback or other flashback mechanisms may be affected differently.
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Göckeler, Katharina, Steffen Terhaar, and Christian Oliver Paschereit. "Residence Time Distribution in a Swirling Flow at Non-Reacting, Reacting, and Steam-Diluted Conditions." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95594.

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Residence time distributions in a swirling, premixed combustor flow are determined by means of tracer experiments and a reactor network model. The measurements were conducted at non-reacting, reacting, and steam-diluted reacting conditions for steam contents of up to 30% of the air mass flow. The tracer distribution was obtained from the light scattering of seeding particles employing the quantitative light sheet technique (QLS). At steady operating conditions, a positive step of particle feed was applied, yielding cumulative distribution functions (CDF) for the tracer response. The shape of the curve is characteristic for the local degree of mixedness. Fresh and recirculating gases were found to mix rapidly at non-reacting and highly steam diluted conditions, whereas mixing was more gradual at dry reacting conditions. The instantaneous mixing near the burner outlet is related to the presence of a large scale helical structure, which was suppressed at dry reacting conditions. Zones of similar mixing time scales, such as the recirculation zones, are identified. The CDF curves in these zones are reproduced by a network model of plug flow and perfectly mixed flow reactors. Reactor residence times and inlet volume flow fractions obtained in this way provide data for kinetic network models.
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10

DeTurris, Dianne. "Fabri Choking in a Two-Dimensional Reacting Flow Mixer-Ejector." In 48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2010. http://dx.doi.org/10.2514/6.2010-384.

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Reports on the topic "Mixed reactant"

1

Ekkad, Srinath V. Evaluation of flow and heat transfer inside lean pre-mixed combustor systems under reacting flow conditions. Office of Scientific and Technical Information (OSTI), August 2018. http://dx.doi.org/10.2172/1463254.

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You might also be interested in the extended bibliographies on the topic 'Mixed reactant' for particular source types:
Journal articles
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