Academic literature on the topic 'First order reaction'
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Journal articles on the topic "First order reaction"
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Ball, David. "Kinetics of Consecutive Reactions: First Reaction, First-Order; Second Reaction, Zeroth Order." Journal of Chemical Education 75, no. 7 (July 1998): 917. http://dx.doi.org/10.1021/ed075p917.
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Croce, A. E. "First-order parallel and consecutive reaction mechanisms — Isosbestic points criterium." Canadian Journal of Chemistry 86, no. 9 (September 1, 2008): 918–24. http://dx.doi.org/10.1139/v08-098.
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A criterium for the selection of reaction mechanism derived from a condition for isosbestic points occurrence is presented. Analytical relationships involving the molar absorption coefficients of the species, which participate in a mechanism of parallel first-order reactions and the corresponding rate coefficients, are also reported. A model system of four species that present overlapping absorption spectra may correspond to the reactant and products of a system of parallel or consecutive first-order reactions. In the first case, under experimental conditions in which the absorbances are additive, the presence of an isosbestic point in the spectrum of the reaction mixture at a given wavelength leads to a time-independent ratio of the degree of advancement of reaction variables. From this, relevant kinetic information may be extracted, namely, the ratio of the reaction rate coefficients. Moreover, the occurrence of isosbestic points allows discarding the second mechanism. This conclusion is independent of the number of absorbing species. Model calculated examples show the application of the equations here derived. The resolution for the general case of mechanisms of N first-order reactions is provided.Key words: chemical kinetics, time-resolved absorption spectra, reaction mechanism.
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Boeker, E. A. "Integrated rate equations for irreversible enzyme-catalysed first-order and second-order reactions." Biochemical Journal 226, no. 1 (February 15, 1985): 29–35. http://dx.doi.org/10.1042/bj2260029.
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Integrated rate equations are presented that describe irreversible enzyme-catalysed first-order and second-order reactions. The equations are independent of the detailed mechanism of the reaction, requiring only that it be hyperbolic and unbranched. The results should be directly applicable in the laboratory.
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Vinnett, Luis, and Kristian E. Waters. "Representation of Kinetics Models in Batch Flotation as Distributed First-Order Reactions." Minerals 10, no. 10 (October 15, 2020): 913. http://dx.doi.org/10.3390/min10100913.
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Four kinetic models are studied as first-order reactions with flotation rate distribution f(k): (i) deterministic nth-order reaction, (ii) second-order with Rectangular f(k), (iii) Rosin–Rammler, and (iv) Fractional kinetics. These models are studied because they are considered as alternatives to the first-order reactions. The first-order representation leads to the same recovery R(t) as in the original domain. The first-order R∞-f(k) are obtained by inspection of the R(t) formulae or by inverse Laplace Transforms. The reaction orders of model (i) are related to the shape parameters of first-order Gamma f(k)s. Higher reaction orders imply rate concentrations at k ≈ 0 in the first-order domain. Model (ii) shows reverse J-shaped first-order f(k)s. Model (iii) under stretched exponentials presents mounded first-order f(k)s, whereas model (iv) with derivative orders lower than 1 shows from reverse J-shaped to mounded first-order f(k)s. Kinetic descriptions that lead to the same R(t) cannot be differentiated between each other. However, the first-order f(k)s can be studied in a comparable domain.
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Strieder, William. "Chemoreceptor diffusion and reaction: first-order kinetics." Chemical Engineering Science 55, no. 14 (April 2000): 2579–84. http://dx.doi.org/10.1016/s0009-2509(99)00538-2.
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Riazi, Mohammad R., and Amir Faghri. "Solid dissolution with first-order chemical reaction." Chemical Engineering Science 40, no. 8 (1985): 1601–3. http://dx.doi.org/10.1016/0009-2509(85)80105-6.
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Wu, Xizun, Wenzhi Zhang, Shengmin Cai, and Degang Han. "A Method for Estimation of Kinetic Parameters; A Simple First-Order Reaction and Two Parallel First-Order Reactions Producing a Common Product." Collection of Czechoslovak Chemical Communications 57, no. 6 (1992): 1196–200. http://dx.doi.org/10.1135/cccc19921196.
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A method is proposed for the treatment of data from a kinetic system of a simple first-order reaction and two parallel first-order reactions, producing a common product. It is based on the solving of a contrary proposition for an ordinary differential equation.
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Vajda, S., and H. Rabitz. "Identifiability and distinguishability of first-order reaction systems." Journal of Physical Chemistry 92, no. 3 (February 1988): 701–7. http://dx.doi.org/10.1021/j100314a024.
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Tóbiás, Roland, László L. Stacho, and Gyula Tasi. "First-order chemical reaction networks I: theoretical considerations." Journal of Mathematical Chemistry 54, no. 9 (June 14, 2016): 1863–78. http://dx.doi.org/10.1007/s10910-016-0655-2.
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Chau, F. T., and K. W. Mok. "Multiwavelength analysis for a first-order consecutive reaction." Computers & Chemistry 16, no. 3 (July 1992): 239–42. http://dx.doi.org/10.1016/0097-8485(92)80009-o.
Full textDissertations / Theses on the topic "First order reaction"
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Castagne, David. "Mathematical modeling of PEM fuel cell cathodes : comparison of first-order and half-order reaction kinetics." Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1448.
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Gibson, Sara Nichols. "Oxidation of pharmaceuticals and personal products by permanganate." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33870.
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Pharmaceuticals and personal care products (PPCPs) are widely used, resulting in trace amounts being detected in the aquatic environment. This presence is of human health and ecological concern and it is necessary to determine the best methods to eliminate them from our waters. The oxidation of PPCPs by permanganate was evaluated using a spectrophotometer to monitor permanganate reduction. Thirty-nine compounds were chosen to represent numerous classifications, including beta blockers, cephalosporins, fluoroquinolones, macrolides, non-steroidal anti-inflammatory drugs, phenol structures, polypeptides, sulfonamides, tetracyclines, and triazines. The reactivity of each compound was determined by measuring the absorbance of permanganate over time as it reacted with an excess of the compound. The absorbance data was fit to a pseudo-first-order reaction model that accounted for the growth of manganese dioxide colloids. The most reactive groups that reduced permanganate within minutes at pH 7.0 were the cephalosporins, phenol structures, and tetracyclines. The majority of the remaining pharmaceuticals and personal care products were moderately or weakly reactive (reducing permanganate within hours). Caffeine, carbadox, monensin, simetone, and tri(2-carboxyethyl)phosphine were poorly reactive (reducing permanganate over days). Metoprolol was the only selected compound that was determined to be potentially non-reactive (no reaction after 1 day). Polarizability and refractive index of the organic compounds showed significant positive correlations (R-squared > 0.50) with the first-order reaction rates for non-steroidal anti-inflammatory drugs and the phenol structures group. The half-life of each PPCP was determined based on a typical dosage of permanganate used for pre-oxidation. Eleven of the thirty-nine PPCPs had a half-life of less than thirty minutes (a typical contact time), indicating that oxidation by permanganate may be a viable option. There are many opportunities for further research in this area, including investigating more PPCPs, physicochemical property correlations, and the impact of water quality conditions
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Onea, Alexandru Aurelian. "Numerical simulation of mass transfer with and without first order chemical reaction in two-fluid flows." Karlsruhe FZKA, 2006. http://bibliothek.fzk.de/zb/berichte/FZKA7274.pdf.
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Onea, Alexandru Aurelian. "Numerical simulation of mass transfer with and without first order chemical reaction in two-fluid flows." Karlsruhe : FZKA, 2007. http://nbn-resolving.de/urn:nbn:de:0005-072749.
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Jabari, Kohpaei Ahmad. "Development of an analytical solution for the parallel second order reaction scheme for chlorine decay modelling." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/572.
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Chlorine is broadly used for water disinfection at the final stage of water treatment because of its high performance to inactivate pathogenic microorganisms, its lower cost compared to other well-known disinfectants and its simple operational needs. However, reaction of chlorine with a wide range of organic and inorganic substances in water causes its decay and formation of chlorinated by-products, which are in some cases carcinogenic and harmful to human health. The major challenge is balancing the risk from these with the cost of operation needed to mitigate the impact. These challenges highlights the importance of having a robust modelling approach for chlorine decay in bulk water as a pre-required step to model the chlorine decay and formation of its by-products in the whole distribution system.In this study, initially, a comprehensive literature review was conducted to investigate and evaluate all existing modelling approaches for chlorine decay prediction especially in bulk water. Among all existing modelling schemes, three models were paid more attention due to their popularity and/or fundamentally valid background. They are first order model, second order model and parallel second order model.During the literature review, comparing the effectiveness of the second order model (SOM) proposed by Clark (1998) with the parallel second order model (PSOM) offered by Kastl et al., (1999), the author found that these two models are both fundamentally sound, although the PSOM had better capability in terms of data fitting, and representing the chlorine decay behaviour is much better than SOM. However, non-existence of analytical solution for PSOM was found to be the major negative point for wide adaptation of PSOM compared to SOM.Trying to understand the basic principles of both models, it was understood that the formulation of SOM was genuine and the researchers who claimed that Clark (1998) made a mistake in deriving the analytical solution were proved wrong. This resulted in having the first publication as a comment in Water Research (Fisher et al., 2010b; Appendix A3).Further study was performed on how SOM was formulated and attempts were made to apply the same methodology to PSOM in order to arrive at an analytical solution. Consequently, making a reasonable assumption, an analytical solution for the parallel second order model was formulated and evaluated against the existing numerical method.As the case study of this research, initially, the previous chlorine decay data from Pilbara Water Treatment Plant was fitted to a first order reaction scheme and it was proved that the data did not comply with it. This was an expected result and the need for other model was validated. For further analysis, fresh water samples were collected from Pilbara Water Treatment Plant to perform chlorine decay tests.Temperature effect on the behaviour of chlorine decay in the bulk water was investigated by integrating Arrhenius equation with PSOM. Three methods of temperature analysis were compared and the best one was recommended for practical application. It was shown that the model was capable enough to properly display the chlorine decay profile when temperature varies.The thesis consists of eight chapters. In chapter 1, a brief description of the research background and the overall objectives of the research are given. Chapter 2 focuses on providing a comprehensive literature review about all involved aspects as well as chlorine decay modelling background. Chapter 3 discusses the methodology and analytical methods for conducting laboratory experiments. Chapter 4 gives a prove that the first order decay model does not show accurate results for chlorine decay prediction and the parallel second order model is much more accurate in predicting chlorine concentration. In Chapter 5, the main part of this research, an analytical solution for the parallel second order model is developed. Chapter 6 evaluates the effectiveness of the parallel second order model against the first and second order model. Within chapter 7, temperature effect on the chlorine decay behaviour and the selected modelling approach is evaluated and chapter 8 gives a brief conclusion and recommendation.
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Onea, Alexandru Aurelian [Verfasser]. "Numerical simulation of mass transfer with and without first order chemical reaction in two-fluid flows / Forschungszentrum Karlsruhe GmbH, Karlsruhe. Alexandru Aurelian Onea." Karlsruhe : FZKA, 2007. http://d-nb.info/986915084/34.
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He, Ruo. "MEMBRANE IMMOBILIZED REACTIVE Fe/Pd NANOPARTICLES: MODELING AND TCE DEGRADATION RESULTS." UKnowledge, 2012. http://uknowledge.uky.edu/cme_etds/14.
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Detoxification of chlorinated organic compound is an important and urgent issue in water remediation nowadays. Trichloroethylene (TCE), as a model compound in this study, has been proved to be degraded effectively by bimetallic nanoparticles (NPs) in solution phase. In this study, Fe/Pd bimetallic NPs were synthesized in poly (acrylic acid) (PAA) functionalized polyvinylidene fluoride (PVDF) microfiltration membranes. TCE dechlorination with these bimetallic NPs was conducted under different pH values and different metal loadings to study the role of corrosion on reaction rates.
One-dimensional mathematical model with pseudo first-order reaction kinetic was introduced to discuss the TCE dechlorination profile in membrane system. Reduction reaction in pores is affected by several parameters including NP loading and size, TCE diffusivity, void volume fraction and surface-area-based reaction rates. This model result indicated that modification is needed to correct the reaction rate obtained from bulk solution in order to represent the actual efficiency of NPs on reduction reaction. In addition, TCE dechlorination mainly occurred near NPs’ surface. Second part of model indicated that reduction mechanism with TCE adsorption-desorption behavior could be used to discuss dechlorination with a high TCE concentration.
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Alkhatib, Rami. "Human locomotion analysis, classification and modeling of normal and pathological vertical ground reaction force signals in elderly." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES029/document.
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La marche est définie par des séquences de gestes cycliques et répétées. Il a été déjà montré que la vitesse et la variabilité de ces séquences peuvent révéler des aptitudes ou des défaillances motrices. L’originalité de ce travail est alors d’analyser et de caractériser les foulées de sujets âgés à partir des signaux de pression issus de semelles instrumentées lors de la marche, au moyen d’outils de traitement du signal. Une étude préliminaire, sur les signaux de pression générés lors de la marche, nous a permis de mettre en évidence le caractère cyclo-stationnaire de ces signaux. Ces paramètres sont testées sur une population de 47 sujets. Tout d'abord, nous avons commencé par un prétraitement des signaux et nous avons montré dans la première de cette thèse que le filtrage peut éliminer une partie vitale du signal. C’est pourquoi un filtre adaptatif basé sur la décomposition en mode empirique a été conçu. Les points de retournement ont été filtrés ensuite en utilisant une technique temps-fréquence appelée «synochronosqueezing». Nous avons également montré que le contenu des signaux de force de marche est fortement affecté par des paramètres inquantifiables tels que les tâches cognitives qui les rendent difficiles à normaliser. C’est pourquoi les paramètres extraits de nos signaux sont tous dérivées par une comparaison inter-sujet. Par exemple, nous avons assimilé la différence dans la répartition de poids entre les pieds. Il est également recommandé dans ce travail de choisir le centre des capteurs plutôt que de compter sur la somme des forces issues du réseau de capteurs pour la classification. Ensuite, on a montré que l’hypothèse de la marche équilibrée et déséquilibrée peut améliorer les résultats de la classification. Le potentiel de cette hypothèse est montré à l'aide de la répartition du poids ainsi que le produit de l'âge × vitesse dans le premier classificateur et la corrélation dans le second classificateur. Une simulation de la série temporelle de VGRF basé sur une version modifiée du modèle de Markov non stationnaire, du premier ordre est ensuite dérivée. Ce modèle prédit les allures chez les sujets normaux et suffisamment pour les allures des sujets de Parkinson. On a trouvé que les trois modes: temps, fréquence et espace sont très utiles pour l’analyse des signaux de force, c’est pourquoi l’analyse de facteurs parallèles est introduite comme étant une méthode de tenseur qui peut être utilisée dans le futurWalking is defined as sequences of repetitive cyclic gestures. It was already shown that the speed and the variability of these sequences can reveal abilities or motorskill failures. The originality of this work is to analyze and characterize the steps of elderly persons by using pressure signals. In a preliminary study, we showed that pressure signals are characterized by cyclostationarity. In this study, we intend to exploit the nonstationarity of the signals in a search for new indicators that can help in gait signal classification between normal and Parkinson subjects in the elderly population. These parameters are tested on a population of 47 subjects. First, we started with preprocessing the vertical ground reaction force (VGRF) signals and showed in this first part of the thesis that filtering can remove a vital part of the signal. That is why an adaptive filter based on empirical mode decomposition (EMD) was built. Turning points are filtered using synochronosqueezing of time-frequency representations of the signal. We also showed that the content of gait force signals is highly affected by unquantifiable parameter such as cognitive tasks which make them hard to be normalized. That is why features being extracted are derived from inter-subject comparison. For example we equated the difference in the load distribution between feet. It is also recommended in this work to choose the mid-sensor rather than relying on summation of forces from array of sensors for classification purposes. A hypothesis of balanced and unbalanced gait is verified to be potential in improving the classification accuracy. The power of this hypothesis is shown by using the load distribution and Age×Speed in the first classifier and the correlation in the second classifier. A time series simulation of VGRF based on a modified version of nonstationary- Markov model of first order is derived. This model successfully predict gaits in normal subjects and fairly did in Parkinson’s gait. We found out that the three modes: time, frequency and space are helpful in analyzing force signals that is why parallel factor analysis is introduced as a tensor method to be used in a future work
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Qamaruz, Zaman Nastaein. "The applicability of batch tests to assess biomethanation potential of organic waste and assess scale up to continuous reactor systems." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2010. http://hdl.handle.net/10092/4025.
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Many of the current methods of assessing anaerobic biodegradability of solid samples require sample modification prior to testing. Steps like sample drying, grinding, re-drying and re-grinding to 2mm or less make the test results difficult to apply to field conditions and could lead to oxygen exposure, possibly distorting the results. Finally, because of a small sample size of about 10-50g w/w, the test result may not be representative of the bulk material.
A new tool dubbed ‘tube’ has been developed, made of 10 cm diameter PVC pipe measuring 43.5 cm long with 3600 ml capacity with caps at both ends. For easy sample introduction, one endcap is fixed while the other is screw capped. A distinctive feature is the wide neck opening of about 10 cm where solid samples can be introduced as is, without further sample modification.
Research has proven the tube applicable across various types of solid organic waste and conditions provided that a suitable organic loading rate is determined. The tube is best operated using 5-7 days pre-digested digested sewage sludge as seed, with minimal mixing and without the addition of nutrients or alkali solution. The test result can be obtained within 4-6 days to 20 days, signifying a 50-75% and 95% substrate degradation, respectively. Irreproducibility seen in some experiments may not only be a function of the seed and the substrate. The organic loading rate (OLR) at which the test is conducted is also influential especially if test is conducted closer to its maximum OLR tolerance where anaerobic process is more erratic.
The performance of a continuous reactor digesting on a similar substrate can be estimated using this new tool. Food waste is established by the tubes to have an ultimate methane potential (B0) of 0.45L CH4/g VS. The same substrate when digested in a continuous reactor will produce about (B) 0.32 L CH4/g VS. The first order rate constant for both systems; batch and continuous are identical at 0.12 to 0.28 d-1. First order kinetics is efficient at modelling the anaerobic degradation when the process is healthy but may be less reliable under an unstable process.
This research recommends the use of kinetics in combination with the experimental data (e.g. HRT, OLR, yield) when planning and designing an industrial plant to avoid overdesign and unnecessary building, maintenance and operating costs.
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Rincon, Guillermo. "Kinetics of the electrocoagulation of oil and grease." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/131.
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Research on the electrocoagulation (EC) of hexane extractable materials (HEM) has been conducted at the University of New Orleans using a proprietary bench-scale EC reactor. The original reactor configuration forced the fluid to follow a vertical upward-downward path. An alternate electrode arrangement was introduced so that the path of flow became horizontal. Both configurations were evaluated by comparing the residence time distribution (RTD) data generated in each case. These data produced indication of internal recirculation and stagnant water when the fluid followed a vertical path. These anomalies were attenuated when the fluid flowed horizontally and at a velocity higher than 0.032 m s-1 . A series of EC experiments were performed using a synthetic emulsion with a HEM concentration of approximately 700 mg l-1. It was confirmed that EC of HEM follows first-order kinetics, and kinetic constants of 0.0441 s-1 and 0.0443 s-1 were obtained from applying both the dispersion and tanks-in-series (TIS) models, respectively. In both cases R2 was 0.97. Also, the TIS model indicated that each cell of the EC behaves as an independent continuous-stirred-tank reactor.
Books on the topic "First order reaction"
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Henriksen, Niels E., and Flemming Y. Hansen. Theories of Molecular Reaction Dynamics. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198805014.001.0001.
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This book deals with a central topic at the interface of chemistry and physics—the understanding of how the transformation of matter takes place at the atomic level. Building on the laws of physics, the book focuses on the theoretical framework for predicting the outcome of chemical reactions. The style is highly systematic with attention to basic concepts and clarity of presentation. Molecular reaction dynamics is about the detailed atomic-level description of chemical reactions. Based on quantum mechanics and statistical mechanics or, as an approximation, classical mechanics, the dynamics of uni- and bimolecular elementary reactions are described. The first part of the book is on gas-phase dynamics and it features a detailed presentation of reaction cross-sections and their relation to a quasi-classical as well as a quantum mechanical description of the reaction dynamics on a potential energy surface. Direct approaches to the calculation of the rate constant that bypasses the detailed state-to-state reaction cross-sections are presented, including transition-state theory, which plays an important role in practice. The second part gives a comprehensive discussion of basic theories of reaction dynamics in condensed phases, including Kramers and Grote–Hynes theory for dynamical solvent effects. Examples and end-of-chapter problems are included in order to illustrate the theory and its connection to chemical problems. The book has ten appendices with useful details, for example, on adiabatic and non-adiabatic electron-nuclear dynamics, statistical mechanics including the Boltzmann distribution, quantum mechanics, stochastic dynamics and various coordinate transformations including normal-mode and Jacobi coordinates.
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Leung, Patrick Sze-lok, and Bijun Xu. The Sino-Japanese War and the Collapse of the Qing and Confucian World Order in the Face of Japanese Imperialism and European Acquiescence. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199670055.003.0019.
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The First Sino-Japanese War (1894–95) has been perceived as a sign of a new East Asian power order, but the legitimacy of the war has yet to be clarified. The Japanese foreign minister Mutsu’s Kenkenroku shows that the reasons claimed by Japan were only pretexts for its ambition to put Korea under its control. The 1885 Convention of Tianjin, which was used to justify the Japanese behaviour, needs to be reinterpreted. The Chinese reaction can be understood by exploration into Confucianism, which opposed wars between equal peers. Meanwhile, the Western powers which invented and developed international law were self-interested and did little to prevent the war. The incident shows that international law, empowered by the strong states, failed to maintain peace efficiently in the late nineteenth century.
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Li, Jie Jack, Chris Limberakis, and Derek A. Pflum. Modern Organic Synthesis in the Laboratory. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780195187984.001.0001.
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Searching for reaction in organic synthesis has been made much easier in the current age of computer databases. However, the dilemma now is which procedure one selects among the ocean of choices. Especially for novices in the laboratory, it becomes a daunting task to decide what reaction conditions to experiment with first in order to have the best chance of success. This collection intends to serve as an "older and wiser lab-mate" one could have by compiling many of the most commonly used experimental procedures in organic synthesis. With chapters that cover such topics as functional group manipulations, oxidation, reduction, and carbon-carbon bond formation, Modern Organic Synthesis in the Laboratory will be useful for both graduate students and professors in organic chemistry and medicinal chemists in the pharmaceutical and agrochemical industries.
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Tal, Yuval. The Social Logic of Colonial Anti-Judaism: Revisiting the Anti-Jewish Crisis in French Algeria, 1889–1902. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190912628.003.0002.
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This chapter examines the social functions of anti-Judaism in French Algeria during the period 1889–1902 by focusing on the roles played by ethnic groups involved in what came to be known as the “anti-Jewish crisis.” The anti-Jewish crisis erupted in the late 1890s, when the three enfranchised ethnic groups living in French Algeria—Frenchmen with roots in France, European immigrants, and local Jews—challenged the established social order in the colony. The chapter first provides a background on the anti-Jewish crisis before discussing the segregated landscape of Algiers and the rise of the French anti-Jewish movement in the early 1890s. It then considers how xenophobia developed among many Frenchmen with regard to European immigrants in French Algeria and the participation of such immigrants in anti-Jewish riots. It also looks at Jewish reaction to the anti-Jewish crisis.
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Gauthier, Christopher R., and Jennifer Mcfarlane-Harris. Nationalism, Racial Difference, and “Egyptian” Meaning in Verdi’s Aida. University of Illinois Press, 2017. http://dx.doi.org/10.5406/illinois/9780252036781.003.0004.
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This chapter examines the dynamics of race and race relations in Giuseppe Verdi's Aida in the context of nationalism in nineteenth-century Egypt. The world premiere of Aida took place at the Cairo Opera House on December 24, 1871. However, there seems to be little information available on the opera's Cairo production, particularly with regards to Egyptian reaction to this first performance. Focusing on its Cairo premiere, this chapter analyzes Aida's libretto and music in order to elucidate the workings of racial difference as it lies on the surface of the opera. It suggests that, for Egyptians, Aida may have spoken to a sense of emergent Egyptian identity. It also reveals Aida's racial dynamics by linking it to discourses of light-skinned Egyptian superiority and dark-skinned African inferiority. Furthermore, the relationships between characters in the opera highlight the specificities of Egypt's relations with its racial-national Others, implying a larger project of Egyptian identity formation through “racial fabrication.”
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Садовников, Василий. Теория гетерогенного катализа. Теория хемосорбции. Publishing House Triumph, 2021. http://dx.doi.org/10.32986/978-5-40-10-01-2001.
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This monograph is a continuation of the monograph by V.V. Sadovnikov. Lateral interaction. Moscow 2006. Publishing house "Anta-Eco", 2006. ISBN 5-9730-0017-6. In this work, the foundations of the theory of heterogeneous catalysis and the theory of chemisorption are more easily formulated. The book consists of two parts, closely related to each other. These are the theoretical foundations of heterogeneous catalysis and chemisorption. In the theory of heterogeneous catalysis, an experiment is described in detail, which must be carried out in order to isolate the stages of a catalytic reaction, to find the stoichiometry of each of the stages. This experiment is based on the need to obtain the exact value of the specific surface area of the catalyst, the number of centers at which the reaction proceeds, and the output curves of each of the reaction products. The procedures for obtaining this data are described in detail. Equations are proposed and solved that allow calculating the kinetic parameters of the nonequilibrium stage and the thermodynamic parameters of the equilibrium stage. The description of the quantitative theory of chemisorption is based on the description of the motion of an atom along a crystal face. The axioms on which this mathematics should be based are formulated, the mathematical apparatus of the theory is written and the most detailed instructions on how to use it are presented. The first axiom: an atom, moving along the surface, is present only in places with minima of potential energy. The second axiom: the face of an atom is divided into cells, and the position of the atom on the surface of the face is set by one parameter: the cell number. The third axiom: the atom interacts with the surrounding material bodies only at the points of minimum potential energy. The fourth axiom: the solution of the equations is a map of the arrangement of atoms on the surface. The fifth axiom: quantitative equations are based on the concept of a statistically independent particle. The formation energies of these particles and their concentration are calculated by the developed program. The program based on these axioms allows you to simulate and calculate the interaction energies of atoms on any crystal face. The monograph is intended for students, post-graduate students and researchers studying work and working in petrochemistry and oil refining.
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Link, Stefan J. Forging Global Fordism. Princeton University Press, 2020. http://dx.doi.org/10.23943/princeton/9780691177540.001.0001.
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As the United States rose to ascendancy in the first decades of the twentieth century, observers abroad associated American economic power most directly with its burgeoning automobile industry. In the 1930s, in a bid to emulate and challenge America, engineers from across the world flocked to Detroit. Chief among them were Nazi and Soviet specialists who sought to study, copy, and sometimes steal the techniques of American automotive mass production, or Fordism. This book traces how Germany and the Soviet Union embraced Fordism amid widespread economic crisis and ideological turmoil. The book recovers the crucial role of activist states in global industrial transformations and reconceives the global thirties as an era of intense competitive development, providing a new genealogy of the postwar industrial order. The book uncovers the forgotten origins of Fordism in Midwestern populism, and shows how Henry Ford's antiliberal vision of society appealed to both the Soviet and Nazi regimes. It explores how they positioned themselves as America's antagonists in reaction to growing American hegemony and seismic shifts in the global economy during the interwar years, and shows how Detroit visitors helped spread versions of Fordism abroad and mobilize them in total war. The book challenges the notion that global mass production was a product of post-World War II liberal internationalism, demonstrating how it first began in the global thirties, and how the spread of Fordism had a distinctly illiberal trajectory.
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Trencsényi, Balázs, Michal Kopeček, Luka Lisjak Gabrijelčič, Maria Falina, Mónika Baár, and Maciej Janowski. The Second World War. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198737155.003.0007.
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The Second World War catalyzed a profound reconfiguration of the political discourse in East Central Europe. A considerable part of the region experienced consecutive occupation regimes, which triggered strategies of playing out the occupiers against each other. A central tenet of any legitimization of collaboration was the idea that the liberal democratic world order had disintegrated and a new totalitarian Zeitgeist had emerged in its stead. In turn, the resistance movements were organized either by communists or by members of the prewar elites. The former had a hard time coping with the Nazi–Soviet friendship in 1939–41, and later had to show their relative independence from the Soviet Union in order to gain legitimacy in their societies. The resistance led by the members of the old elites, in turn, had to prove that they were able to modify their old ideas for a new situation. The chapter also reviews the first reactions to the genocidal policies during the war.
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Retallack, James. Politics in a New Key. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199668786.003.0013.
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In October 1909 Saxony’s new plural suffrage was tested for the first and only time. This chapter begins with an examination of Social Democratic strength and the election campaign. The chapter ends by citing different answers to a question that had resonance beyond Saxony’s borders: Did the plural suffrage save the existing social and political order from Social Democracy, or was it a grave miscalculation? In between, sections are devoted to the actions and reactions of anti-socialist groups during the campaign; to the role of left-liberal and National Liberal parties between Left and Right; to statistical analysis of plural voting and its impact on the parliamentary representation of workers and the lower-middle classes; and to contemporaries’ realization that statistical predictions about the plural suffrage’s effect on voting outcomes were flawed.
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Alonso, Paul. Satiric TV in the Americas. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190636500.001.0001.
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In the post-truth era, postmodern satiric media have emerged as prominent critical voices playing an unprecedented role at the heart of public debate, filling the gaps left not only by traditional media but also by weak social institutions and discredited political elites. Satiric TV in the Americas analyzes some of the most representative and influential satiric TV shows on the continent (focusing on cases in Argentina, Peru, Ecuador, Mexico, Chile, and the United States) in order to understand their critical role in challenging the status quo, traditional journalism, and the prevalent local media culture. It illuminates the phenomenon of satire as resistance and negotiation in public discourse, the role of entertainment media as a site where sociopolitical tensions are played out, and the changing notions of journalism in today’s democratic societies. Introducing the notion of “critical metatainment”—a postmodern, carnivalesque result of and a transgressive, self-referential reaction to the process of tabloidization and the cult of celebrity in the media spectacle era—Satiric TV in the Americas is the first book to map, contextualize, and analyze relevant cases to understand the relation between political information, social and cultural dissent, critical humor, and entertainment in the region. Evaluating contemporary satiric media as distinctively postmodern, multilayered, and complex discursive objects that emerge from the collapse of modernity and its arbitrary dichotomies, Satiric TV in the Americas also shows that, as satiric formats travel to a particular national context, they are appropriated in different ways and adapted to local circumstances, thus having distinctive implications.
Book chapters on the topic "First order reaction"
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Gooch, Jan W. "First-Order Reaction." In Encyclopedic Dictionary of Polymers, 893. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_13758.
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Babanli, Mahsati. "Fuzzy Stability Analysis of an Isothermal First-Order Reaction." In 13th International Conference on Theory and Application of Fuzzy Systems and Soft Computing — ICAFS-2018, 444–50. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-04164-9_59.
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Adler, James H., Scott MacLachlan, and Niall Madden. "First-Order System Least Squares Finite-Elements for Singularly Perturbed Reaction-Diffusion Equations." In Large-Scale Scientific Computing, 3–14. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-41032-2_1.
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Prodanov, Dimiter. "First-Order Reaction-Diffusion System with Space-Fractional Diffusion in an Unbounded Medium." In Large-Scale Scientific Computing, 65–70. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97549-4_7.
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Pratap Kumar, J., Jawali C. Umavathi, Prashant G. Metri, and Sergei Silvestrov. "Effect of First Order Chemical Reaction on Magneto Convection in a Vertical Double Passage Channel." In Engineering Mathematics I, 247–79. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-42082-0_15.
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Suk, Heejun, Byung-Gon Chae, and Junghae Choi. "Semianalytical Solutions for Multispecies Transport Coupled with a Sequential First-Order Reaction Network Using GITT Techniques." In Geostatistical and Geospatial Approaches for the Characterization of Natural Resources in the Environment, 45–49. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-18663-4_8.
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Sutin, N. "Of First Order." In Inorganic Reactions and Methods, 22–23. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2007. http://dx.doi.org/10.1002/9780470145302.ch15.
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Prabhakaran, S., and L. Jones Tarcius Doss. "Total Variation Diminishing Finite Volume Scheme for Multi Dimensional Multi Species Transport with First Order Reaction Network." In Springer Proceedings in Mathematics & Statistics, 481–98. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4646-8_38.
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Brovchenko, Igor, and Vladimir Maderich. "Modelling Radionuclide Scavenging in the Ocean by a Particle Tracking in Multicomponent Medium with First-Order Reaction Kinetics." In Advances in Intelligent Systems and Computing, 36–46. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58124-4_4.
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Mariappan, Manikandan, John J. H. Miller, and Valarmathi Sigamani. "A First-Order Convergent Parameter-Uniform Numerical Method for a Singularly Perturbed Second-Order Delay-Differential Equation of Reaction–Diffusion Type with a Discontinuous Source Term." In Springer Proceedings in Mathematics & Statistics, 73–94. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-7546-1_5.
Full textConference papers on the topic "First order reaction"
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Pena, Fabrício, and Marcelo De Lemos. "Numerical investigation of Fe2O3-Al Thermite reaction using zero and first-order kinetic models." In 19th Brazilian Congress of Thermal Sciences and Engineering. ABCM, 2022. http://dx.doi.org/10.26678/abcm.encit2022.cit22-0250.
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Loscar, E. S. "Study of a First-Order Irreversible Phase Transition in the Yaldran-Khan Catalyzed Reaction Model." In MODELING OF COMPLEX SYSTEMS: Seventh Granada Lectures. AIP, 2003. http://dx.doi.org/10.1063/1.1571341.
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Egan, Malcolm, Bao Quoc Tang, and Bayram Cevdet Akdeniz. "On the Input-Output Relationship for Molecular Communications in General First-Order Chemical Reaction-Diffusion Systems." In NANOCOM '19: The Sixth Annual ACM International Conference on Nanoscale Computing and Communication. New York, NY, USA: ACM, 2019. http://dx.doi.org/10.1145/3345312.3345477.
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Nagy, Endre. "Mass Transport Through Biocatalytic Membrane Reactors." In ASME 2008 9th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2008. http://dx.doi.org/10.1115/esda2008-59403.
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A mathematical model and its solution were developed to calculate the mass transport through catalytic membrane layer by means of explicit, closed expressions even in the case of the nonlinear Michaelis-Menten reaction kinetics and/or of variable mass transport — diffusion coefficient, convective velocity — parameters. Some typical examples on the Thiele modulus, applying the Michaelis-Menten kinetics and its limiting cases, namely the first-order kinetic (KM≫cm) and zero-order kinetic (cm≫KM) are shown for the prediction of the concentration distribution and the mass transfer rates as a function of the reaction modulus, namely first-order- and the zero-order reactions. It was shown the significant differences of the results obtained by the three different reaction orders.
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Mohankumar, K. V., and K. Kannan. "A New Approach in Kinetic Modeling Using Thermodynamic Framework for Chemically Reacting Systems and Oxidative Ageing in Polymer Composites." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64436.
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A thermodynamic framework for chemically reacting systems is put to use in kinetic modeling of any chemical system with N species undergoing M reactions. A new approach of deriving kinetic models from a Gibbs potential, of multivariate polynomial function, is demonstrated with an example of single reaction system involving three species. Also, the usual first order kinetics is deduced as a special case in the example. The distinct advantages of the new approach lies in obtaining the evolution of concentrations of species, their individual chemical potentials and the specific Gibbs potential and is demonstrated for a single reaction system as an example. Oxidation in polymer composites is studied with a coupled reaction-diffusion model obtained using first order kinetics and is solved for a boundary value problem that predicts the concentration of species over space and time. Concentration of oxidized products is correlated with modulus of aged sample and degradation effects is calculated in case of simple torsion.
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Al-Raqom, Fotouh, and James F. Klausner. "Fluidized Bed Kinetics for Hydrogen Production Through Steam Iron Oxidation." In ASME 2013 7th International Conference on Energy Sustainability collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/es2013-18156.
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Kinetic analysis is essential for chemical reactor modeling. This study proposes a methodology to use available kinetic analysis methodologies, including conventional (modelistic) graphical representation, isoconversional (model free), models based on first principles and reduced time scale analysis (Sharp and Hancock procedure) to predict the kinetics of an investigated reaction. Even though these methods have some limitations, a methodology comprised of combining their results can help in determining the kinetic parameters for reaction. The isoconversional approach can be used to determine the activation energy without the need of using a reaction model. The modelistic graphical representation can aid is determining the group (i.e. diffusion, first order, phase boundary or nucleation) to which the reaction generally belongs. The reduced time scale analysis can guide in isolating the reaction kinetics in the early stages of the reaction when the conversion ranges between 0.15 and 0.5. This proposed methodology uses the various methods and applies them to experimental data for high temperature reactions in fluidized bed reactors. Particular attention is given to steam driven iron oxidation kinetics for hydrogen production. When only the modelistic approach is used, the activation energy computed using the selected models varies from 59–183 kJ/mol, depending on the model used. However, by combining the predictive capabilities of various approaches discussed in this study, the activation energy range narrows to 80–147 kJ/mol. It is also shown that the iron oxidation with steam under the studied conditions can be described by a combination of two models. The early stage of the reaction is represented by either a contracting volume or first order model. Later stages of reaction can be described by either a contracting volume, first order or 3-D diffusion model. In addition, when analyzing reaction kinetics using a fundamental approach, it is observed that the fluidized bed oxidation reaction of iron with pure steam can be best represented by a combination of two mechanisms, namely shrinking sphere surface area and diffusion controlled mechanisms and the estimated activation energy is 103 kJ/mol.
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Jarzębowska, Elżbieta, Krzysztof Augustynek, and Andrzej Urbaś. "Computational Reference Dynamical Model of a Multibody System With First Order Constraints." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67969.
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The paper presents a development of a computational based procedure for generation of constrained system dynamical models. The constraints may be both holonomic and first order nonholonomic, either material or nonmaterial. The latter ones are referred to as programmed and they are imposed by a designer, a control engineer as a control goal, or may come from controlled system performance requirements. The procedure for generation of constrained dynamics provides then reference dynamical models, i.e. models whose solutions satisfy all the constraints put upon them. These models may serve as motion planners for control. The distinctions between the presented approach and the ones reported in the literature are that the constraints may be material or nonmaterial and the final equations of motion are derived in the reduced state form, i.e. constraint reaction forces are eliminated at the equations derivation level but not afterwards as in the case of the Lagrange approach. This is the essential advantage of our approach and this one computational procedure may serve both reference and control oriented dynamical models derivation. The procedure is applied to a manipulator model whose end effector is subjected to a programmed constrained.
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Piovoso, M. J., K. A. Kosanovich, V. Rokhlenko, and A. Guez. "A Comparison of Three Nonlinear Controller Designs Applied to a Non-Adiabatic First-Order Exothermic Reaction in a CSTR." In 1992 American Control Conference. IEEE, 1992. http://dx.doi.org/10.23919/acc.1992.4792114.
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van Antwerpen, H. J., and G. P. Greyvenstein. "A Second-Order Accurate Convection Heat Transfer Discretisation Scheme for a Systems Simulation Reactor Model." In Fourth International Topical Meeting on High Temperature Reactor Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/htr2008-58158.
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Nuclear reactor behaviour is determined by the relation between the temperature and the effective neutron reaction cross-sections of the materials in the reactor core. In order to accurately calculate the material temperatures, heat transfer to the reactor coolant is of critical importance. To increase the accuracy of heat transfer calculation, this paper presents a second-order accurate convection heat transfer discretisation for application in two or more dimensions in a finite-volume discretisation. This discretisation is compared to a first-order accurate scheme by means of a grid dependence study on representative reactor geometry. To obtain a certain level of accuracy, the use of second-order accurate convection discretisation reduced the solution time by up to 60 percent, as the second-order accurate scheme required fewer grid points than the first-order accurate scheme. This is of particular importance for systems simulation reactor models, as they use the minimum number of grid points and have to run at the highest possible simulation speed. This study was done using the systems simulation code Flownex.
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Drost, Kevin, Benn Eilers, Daniel Peterson, Sourabh V. Apte, Vinod Narayanan, and John Schmitt. "Detailed Numerical Modeling of a Microchannel Reactor for Methane-Steam Reforming." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44664.
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Numerical modeling of methane-steam reforming is performed in a microchannel with heat input through Palladium-deposited channel walls corresponding to the experimental setup of Eilers [1]. The low-Mach number, variable density Navier-Stokes equations together with multicomponent reactions are solved using a parallel numerical framework. Methane-steam reforming is modeled by three reduced-order reactions occurring on the reactor walls. The surface reactions in the presence of Palladium catalyst are modeled as Neumann boundary conditions to the governing equations. Use of microchannels with deposited layer of Palladium catalyst gives rise to a non-uniform distribution of active reaction sites. The surface reaction rates, based on Arrhenius type model and obtained from literature on packed-bed reactors, are modified by a correction factor to account for these effects. The reaction-rate correction factor is obtained by making use of the experimental data for specific flow conditions. The modified reaction rates are then used to predict hydrogen production in a microchannel configuration at different flow rates and results are validated to show good agreement. It is found that the endothermic reactions occurring on the catalyst surface dominate the exothermic water-gas-shift reaction. It is also observed that the methane-to-steam conversion occurs rapidly in the first half of the mircochannel. A simple one-dimensional model solving steady state species mass fraction, energy, and overall conservation of mass equations is developed and verified against the full DNS study to show good agreement.
Reports on the topic "First order reaction"
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Favorite, Jeffrey A. SENSMG: First-Order Sensitivities of Neutron Reaction Rates, Reaction-Rate Ratios, Leakage, keff, and α Using PARTISN. Office of Scientific and Technical Information (OSTI), November 2016. http://dx.doi.org/10.2172/1333129.
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Favorite, Jeffrey A. (U) SENSMG: First-Order Sensitivities of Neutron Reaction Rates, Reaction-Rate Ratios, Leakage, keff, α, and Subcritical Multiplication Using PARTISN. Office of Scientific and Technical Information (OSTI), September 2019. http://dx.doi.org/10.2172/1530773.
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Favorite, Jeffrey. (U) SENSMG: First-Order Sensitivities of Neutron Reaction Rates, Reaction-Rate Ratios, Leakage, keff, α, and Subcritical Multiplication Using PARTISN. Office of Scientific and Technical Information (OSTI), August 2022. http://dx.doi.org/10.2172/1884735.
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Asenath-Smith, Emily, Emma Ambrogi, Eftihia Barnes, and Jonathon Brame. CuO enhances the photocatalytic activity of Fe₂O₃ through synergistic reactive oxygen species interactions. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42131.
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Iron oxide (α-Fe₂O₃, hematite) colloids were synthesized under hydrothermal conditions and investigated as catalysts for the photodegradation of an organic dye under broad-spectrum illumination. To enhance photocatalytic performance, Fe₂O₃ was combined with other transition-metal oxide (TMO) colloids (e.g., CuO and ZnO), which are sensitive to different regions of the solar spectrum (far visible and ultraviolet, respectively), using a ternary blending approach for compositional mixtures. For a variety of ZnO/Fe₂O₃/CuO mole ratios, the pseudo-first-order rate constant for methyl orange degradation was at least double the sum of the individual Fe₂O₃ and CuO rate constants, indicating there is an underlying synergy governing the photocatalysis reaction with these combinations of TMOs. A full compositional study was carried out to map the interactions between the three TMOs. Additional experiments probed the identity and role of reactive oxygen species and elucidated the mechanism by which CuO enhanced Fe₂O₃ photodegradation while ZnO did not. The increased photocatalytic performance of Fe2O3 in the presence of CuO was associated with hydroxyl radical ROS, consistent with heterogeneous photo-Fenton mechanisms, which are not accessible by ZnO. These results imply that low-cost photocatalytic materials can be engineered for high performance under solar illumination by selective pairing of TMOs with compatible ROS.
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McNab, W. W. Jr. First-order kinetics-controlled multiple species reactive transport of dissolved organic compounds in groundwater: Development and application of a numerical model. Office of Scientific and Technical Information (OSTI), May 1990. http://dx.doi.org/10.2172/6628114.
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Kimhi, Ayal, Barry Goodwin, Ashok Mishra, Avner Ahituv, and Yoav Kislev. The dynamics of off-farm employment, farm size, and farm structure. United States Department of Agriculture, September 2006. http://dx.doi.org/10.32747/2006.7695877.bard.
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Objectives: (1) Preparing panel data sets for both the United States and Israel that contain a rich set of farm attributes, such as size, specialization, and output composition, and farmers’ characteristics such as off-farm employment status, education, and family composition. (2) Developing an empirical framework for the joint analysis of all the endogenous variables of interest in a dynamic setting. (3) Estimating simultaneous equations of the endogenous variables using the panel data sets from both countries. (4) Analyzing, using the empirical results, the possible effects of economic policies and institutional changes on the dynamics of the farm sector. An added objective is analyzing structural changes in farm sectors in additional countries. Background: Farm sectors in developed countries, including the U.S. and Israel, have experienced a sharp decline in their size and importance during the second half of the 20th century. The overall trend is towards fewer and larger farms that rely less on family labor. These structural changes have been a reaction to changes in technology, in government policies, and in market conditions: decreasing terms of trade, increasing alternative opportunities, and urbanization pressures. As these factors continue to change, so does the structure of the agricultural sector. Conclusions: We have shown that all major dimensions of structural changes in agriculture are closely interlinked. These include farm efficiency, farm scale, farm scope (diversification), and off-farm labor. We have also shown that these conclusions hold and perhaps even become stronger whenever dynamic aspects of structural adjustments are explicitly modeled using longitudinal data. While the results vary somewhat in the different applications, several common features are observed for both the U.S. and Israel. First, the trend towards the concentration of farm production in a smaller number of larger farm enterprises is likely to continue. Second, at the micro level, increased farm size is negatively associated with increased off-farm labor, with the causality going both ways. Third, the increase in farm size is mostly achieved by diversifying farm production into additional activities (crops or livestock). All these imply that the farm sector converges towards a bi-modal farm distribution, with some farms becoming commercial while the remaining farm households either exit farming altogether or continue producing but rely heavily on off-farm income. Implications: The primary scientific implication of this project is that one should not analyze a specific farm attribute in isolation. We have shown that controlling for the joint determination of the various farm and household attributes is crucial for obtaining meaningful empirical results. The policy implications are to some extent general but could be different in the two countries. The general implication is that farm policy is an important determinant of structural changes in the farm sector. For the U.S., we have shown the different effects of coupled and decoupled (direct) farm payments on the various farm attributes, and also shown that it is important to take into account the joint farm-household decisions in order to conduct a meaningful policy analysis. Only this kind of analysis explains the indirect effect of direct farm payments on farm production decisions. For Israel, we concluded that farm policy (or lack of farm policy) has contributed to the fast structural changes we observed over the last 25 years. The sharp change of direction in farm policy that started in the early 1980s has accelerated structural changes that could have been smoother otherwise. These accelerated structural changes most likely lead to welfare losses in rural areas.
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Sengupta-Gopalan, Champa, Shmuel Galili, and Rachel Amir. Improving Methionine Content in Transgenic Forage Legumes. United States Department of Agriculture, February 2001. http://dx.doi.org/10.32747/2001.7580671.bard.
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Leguminous forage crops are high in proteins but deficient in S- amino acids. It has been shown that both wool quality and milk production can be limited by the post-ruminal supply of sulfur-containing amino acids. Efforts to use conventional plant breeding and cell selection techniques to increase the S-amino acid content of alfalfa have met with little success. With the objective to increase the S-amino acid content of forage legumes, the goal of this project was to co- express the methionine rich zein genes from corn along with a gene for a key enzyme in methionine biosynthesis, aspartate kinase(AK). The zeins are seed storage proteins from corn and are groupec into four distinct classes based on their amino acid sequence homologies. The b-zein (15kd) and the 6zein (10kD and 18kD) have proportionately high levels of methionine (10%, 22% and 28%, respectively). Initial studies from our lab had shown that while the 15kD zein accumulated to high levels in vegetative tissues of transgenic tobacco the l0kD zein did not. However, co-expression of the 10kD zein with the 15kD zein genes in tobacco showed stabilization of the 10kD zein and the co-localization of the 10kD and 15kD zein proteins in unique ER derived protein bodies. AK is the key enzyme for producing carbon skeletons for all amino acids of the aspartate family including methionine. It is, however, regulated by end-product feedback inhibition. The specific objectives of this proposal were: i. to co-express the 15kD zein with the 10/18kD zein genes in alfalfa in order to enhance the level of accumulation of the 10/18kD zein; ii. to increase methionine pools by expressing a feedback insensitive AK gene in transformants co-expressing the 15kD and 10/18kD zein genes. The Israeli partners were successful in expressing the AK gene in alfalfa which resulted in an increase in free and bound threonine but not in methionine (Galili et al., 2000). Since our target was to increase methionine pools, we changed our second objective to replace the AK gene with the gene for cystathionine gamma synthase (CGS) in the co-expression studies. The first methionine specific reaction is catalyzed by CGS. An additional objective was to develop a transformation system for Berseem clover, and to introduce the appropriate gene constructs into it with the goal of improving their methionine content. Genes for the 15kD zein along with the genes for either the 10kD or 18kD zein have been introduced into the same alfalfa plant both by sexual crosses and by re-transformation. Analysis of these zein co-expressors have shown that both the IOkD and 18kD zein levels go up 5 to 10 fold when co-expressed with the 15kD zein (Bagga et al., MS in preparation). Incubation of the leaves of transgenic alfalfa co-expressing the 15kD and 10kD zein genes, in the rumen of cows have shown that the zein proteins are stable in the rumen. To increase the level of zein accumulation in transgenic alfalfa different promoters have been used to drive the zein genes in alfalfa and we have concluded that the CaMV 35S promoter is superior to the other strong leaf -specific promoters. By feeding callus tissue of alfalfa plants co-expressing the 15kD and 10kD zein genes with methionine and its precursors, we have shown that the zein levels could be significantly enhanced by increasing the methionine pools. We have now introduced the CGS gene (from Arabidopsis; kindly provided to us by Dr. Leustek), into the 15kD zein transformants and experiments are in progress to check if the expression of the CGS gene indeed increases the level of zein accumulation in alfalfa. We were not successful in developing a transformation protocol for Berseem clover.
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Shenker, Moshe, Paul R. Bloom, Abraham Shaviv, Adina Paytan, Barbara J. Cade-Menun, Yona Chen, and Jorge Tarchitzky. Fate of Phosphorus Originated from Treated Wastewater and Biosolids in Soils: Speciation, Transport, and Accumulation. United States Department of Agriculture, June 2011. http://dx.doi.org/10.32747/2011.7697103.bard.
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Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.
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L51599 The Significance of Local Hard Zones on Outside of Girth Welds. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), July 1989. http://dx.doi.org/10.55274/r0010097.
Full textAbstract:
In petrochemical and oil and gas production plant the presence of sour H2S containing environments poses problems with regard to material behavior. The corrosion reaction between H2S and steel produces atomic hydrogen, which enters the steel and may, for example, lead to hydrogen pressure cracking (HPC) if steel quality is such that inclusion levels promote the entrapment of hydrogen gas. Fortunately this problem may be readily controlled by attention to steel cleanliness. A potentially more serious problem relating to sour environments is sulphide stress cracking (SSC), when the presence of hydrogen may lead to stress corrosion cracking in a susceptible material. In carbon-manganese steels, susceptibility to SSC is associated with a hardened microstructure and control of the problem therefore requires limitations on material hardness. This is especially important in welded structures where the rapid cooling associated with welding may lead to a hardened heat affected zone (HAZ), together with significant residual welding stress. To determine to what extent a relaxation in external hardness could be possible, The Welding Institute proposed a program of work to study the influence of hardness and stress levels on the cracking propensity of GMA welds in pipeline steel. The project was to be carried out in two phases: in the first, the hardness limit for internal GMA bead on pipe welds (simulating weld root regions) was to be determined in a sour (NACE) solution; in Phase 2, external bead on pipe welds (simulating weld cap regions) would be assessed, again with the sour environment on the inside of the pipe. This report presents the results of both phases of the study. In order to study the influence of wall thickness on cracking behavior, seamless pipe materials to API-5L-X52 specification were obtained in 408 mm (16 in) diameter with nominal wall thickness of 9.5, 12.7, 19.0 and 25.4 mm (0.37, 0.5, 0.75 and 1.0 in). Chemical analysis results are given. The materials were supplied in accordance with NACE MR-01-75 hardness specifications (22 HRC max), although no additional requirements were specified. Pipe B, which was obtained from a different supplier to the remaining pipes, had significantly higher sulfur content. Some variations existed between parent material microstructures, although all may be considered typical of the grade of steel. This program seeks to determine the threshold hardness level for sour service of as-deposited (un re-heated) weldment regions in the capping pass of girth welds in pipeline steel. Assessment has been made by comparing the cracking behavior in the NACE TM-01-77 test environment of internal and external single pass welds produced with a range of conditions by the GMAW process.