Journal articles on the topic 'Reacting experiments'
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1
Ryding, M. J., A. S. Zatula, P. U. Andersson, and E. Uggerud. "Reactions of H+(pyridine)m(H2O)n and H+(NH3)1(pyridine)m(H2O)n with NH3: experiments and kinetic modelling." Atmospheric Chemistry and Physics 12, no. 6 (March 16, 2012): 2809–22. http://dx.doi.org/10.5194/acp-12-2809-2012.
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Abstract. Reactions between pyridine containing water cluster ions, H+(pyridine)1(H2O)n, H+(pyridine)2(H2O)n and H+(NH3)1(pyridine)1(H2O)n (n up to 15) with NH3 have been studied experimentally using a quadrupole time-of-flight mass spectrometer. The product ions in the reaction between H+(pyridine)m(H2O)n (m = 1 to 2) and NH3 have been determined for the first time. It is found that the reaction mainly leads to cluster ions of the form H+(NH3)1(pyridine)m(H2O)n-x, with x = 1 or 2 depending on the initial size of the reacting cluster ion. For a given number of water molecules (from 5 to 15) in the cluster ion, rate coefficients are found to be slightly lower than those for protonated pure water clusters reacting with ammonia. The rate coefficients obtained from this study are used in a kinetic cluster ion model under tropospheric conditions. The disagreement between ambient ground level measurements and previous models are discussed in relation to the results from our model and future experimental directions are suggested.
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ASO, Shigeru. "Report on "High Temperature Reacting Gas: Experiments and Computations"." Journal of the Japan Society for Aeronautical and Space Sciences 46, no. 533 (1998): 320–22. http://dx.doi.org/10.2322/jjsass1969.46.320.
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Brown, R. J., and R. W. Bilger. "Experiments on a reacting plume—1. Conventional concentration statistics." Atmospheric Environment 32, no. 4 (February 1998): 611–28. http://dx.doi.org/10.1016/s1352-2310(97)00294-x.
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Brown, R. J., and R. W. Bilger. "Experiments on a reacting plume—2. Conditional concentration statistics." Atmospheric Environment 32, no. 4 (February 1998): 629–46. http://dx.doi.org/10.1016/s1352-2310(97)00295-1.
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Li, Shou Hai, Xue Juan Yang, Kun Huang, Mei Li, and Jian Ling Xia. "Preparation and Characterization of Dimer Fatty Acids-Based Vinyl Ester Resin Monomer." Advanced Materials Research 721 (July 2013): 86–89. http://dx.doi.org/10.4028/www.scientific.net/amr.721.86.
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Novel dimer fatty acids-based vinyl ester resin monomer was prepared via simple ring-opening and esterification reaction with the aid of dimer fatty acids (DA) and glycidyl methacrylate (GMA) as raw material. The effects of different catalyst system, reacting time and reacting temperature on the yield, color, and viscosity of the final product were analyzed. The results of optimal experiments showed that BTEAC catalyst could make the final product with moderate viscosity and lighter color, the optimal BTEAC catalyst addition amount was 0.5wt.%, the optimal reacting temperature and reacting time was 115 °C and 2h, respectively. FTIR and 13C-NMR demonstrated that the target product had been successfully synthesized.
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Yasunaga, N., S. Furukawa, Y. Kawaai, and J. Hirotsuji. "Investigation of radical reactions for efficiency improvement in ozone-hydrogen peroxide treatment." Water Science and Technology 43, no. 2 (January 1, 2001): 205–12. http://dx.doi.org/10.2166/wst.2001.0091.
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It was verified by laboratory-scale experiments that the two-port ozone injection method was more advantageous for reaction efficiency in the ozone-hydrogen peroxide treatment than the conventional one-port ozone injection method under the condition of same ozone dose. The reason for this effectiveness was also investigated in detail by computer simulations in the wide range of the rate constant of OH radical reacting with TOC (kTOC). The laboratory-scale experiments revealed that the amount of TOC decomposed (δTOC) increased by up to 41% by the two-port injection method, indicating a 27% improvement in δO3/δTOC. A detailed investigation of these experimental results by computer simulations showed that by injecting ozone in two ports the amount of ozone consumed for the OH radical formation was increased more remarkably than that of ozone consumed for the radical chain reactions, and that the amount of OH radical reacting with TOC was increased more strikingly than that with ozone. Furthermore, it was found that the smaller the kTOC value within 105–109 M–1s–1 was, the more advantageous for the reaction efficiency the two-port injection method was.
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Yang, Fafu, Yanhua Wang, Hongyu Guo, Jianwei Xie, and Zhiqiang Liu. "Novel lariat calix[4]-1,3-aza-crowns with two branched chains — The excellent phase transfer catalysts for nucleophilic substitution reaction." Canadian Journal of Chemistry 88, no. 7 (July 2010): 622–27. http://dx.doi.org/10.1139/v10-061.
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By reacting calix[4]-1,3-diethoxylaminoethyl derivative (2) with phenyl isothiocyanate, novel dendritic calix[4]arene derivative (3) with two different branched chains was synthesized in a yield of 78%. By reacting compound 2 with 1,6-diisocyanatohexane or N,N′-bis(2-chloracetamide)ethylene in a “1 + 1” intermolecular addition mode, novel lariat calix[4]-1,3-aza-crowns (4 and 5, respectively) with two branched ethoxyl chains were prepared in reasonable yields. The composition, structures, and conformations of all new compounds were confirmed by elemental analyses, IR, ESI-MS, 1H NMR, and so forth. The liquid–liquid extraction experiments showed that all new hosts possessed good extraction abilities towards soft and hard metal cations. The liquid membrane transport experiments suggested that they had good transport abilities for K+ and Ag+. The experiments of phase transfer catalysis indicated that they possessed excellent catalytic properties of aromatic nucleophilic substitution reaction and benzyl nucleophilic substitution. The optimum yields of products in catalytic reaction were as high as approximately 100%.
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González, U. F., S. F. Shen, and Claude Cohen. "Rheological characterization of fast-reacting thermosets through spiral flow experiments." Polymer Engineering & Science 32, no. 3 (February 1992): 172–81. http://dx.doi.org/10.1002/pen.760320303.
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Salvitti, Chiara, Federico Pepi, Anna Troiani, and Giulia de Petris. "Intracluster Sulphur Dioxide Oxidation by Sodium Chlorite Anions: A Mass Spectrometric Study." Molecules 26, no. 23 (November 24, 2021): 7114. http://dx.doi.org/10.3390/molecules26237114.
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The reactivity of [NaL·ClO2]− cluster anions (L = ClOx−; x = 0–3) with sulphur dioxide has been investigated in the gas phase by ion–molecule reaction experiments (IMR) performed in an in-house modified Ion Trap mass spectrometer (IT-MS). The kinetic analysis revealed that SO2 is efficiently oxidised by oxygen-atom (OAT), oxygen-ion (OIT) and double oxygen transfer (DOT) reactions. The main difference from the previously investigated free reactive ClO2− is the occurrence of intracluster OIT and DOT processes, which are mediated by the different ligands of the chlorite anion. This gas-phase study highlights the importance of studying the intrinsic properties of simple reacting species, with the aim of elucidating the elementary steps of complex processes occurring in solution, such as the oxidation of sulphur dioxide.
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Li, Lang, Rengkang Liang, Ye Tian, Jianjun Shi, Jieyu Liu, and Gang Huang. "Unified algorithm of chemically reacting flows at all speeds." Advances in Mechanical Engineering 14, no. 11 (November 2022): 168781322211367. http://dx.doi.org/10.1177/16878132221136762.
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Based on traditional 3-D multi-component NS(Navier-stokes) equations, with chemical reaction Preconditioning method was analyzed and the preconditioning matrix was applied for the pseudo-time derivative term of the equations. Preconditioned AUSM+-up scheme was used for space discretization, with implicit time integration LU-SGS (Lower-Upper Symmetric Gauss-Seidel). These two schemes were combined to develop a unified algorithm for flows at all speeds. In addition, Numerical experiments of flows from low speed to high speed, with and without chemical reaction, were performed in this paper. By comparing the results of simulations with experiments showed the algorithm utilized the imposed preconditioning matrix, obtained better results. It was fairly well demonstrated that the improved methods can be applied efficiently for chemical reacting flow at all speeds.
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Huang, Zong Hao, Long Hao Qi, Wei Pan, and He Zhuo Miao. "Synthesis of Aluminum Nitride by Nitridation of γ-Al2O3 Nanoparticles in Flowing Ammonia." Key Engineering Materials 368-372 (February 2008): 1116–18. http://dx.doi.org/10.4028/www.scientific.net/kem.368-372.1116.
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Aluminum nitride (AlN) powder was synthesized by gas reduction–nitridation of γ-Al2O3, using NH3 as the reactant gas. The results showed that AlN can be fabricated by this process at 1100°C for over 480 min in the flowing NH3 atmosphere. However, no AlN was found in the products synthesized at 1300°C and 1400°C, which was different from the former reports. A series of experiments with different parameters were carried out, and the effects of reacting temperature and time on the synthesis of AlN were investigated. The reaction mechanism was also studied.
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Borghini, Giulio, Patrizia Fumagalli, and Elisabetta Rampone. "Melt–rock interactions in a veined mantle: pyroxenite–peridotite reaction experiments at 2 GPa." European Journal of Mineralogy 34, no. 1 (February 16, 2022): 109–29. http://dx.doi.org/10.5194/ejm-34-109-2022.
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Abstract. Interaction between peridotite and pyroxenite-derived melts can significantly modify the mineralogy and chemistry of the upper mantle, enhancing its heterogeneity, by creating re-fertilized peridotites and secondary-type pyroxenites. We experimentally investigated the reaction between a fertile lherzolite and MgO-rich basaltic andesite produced by partial melting of an olivine-free pyroxenite at 2 GPa and 1300–1450 ∘C. The aim was to constrain the rate and style of melt–peridotite reaction mostly as a function of temperature, i.e. assuming variable physical status of the host peridotite. Experiments juxtaposed pyroxenite on a synthesized fertile lherzolite to evaluate the modal and mineral compositional changes in the fertile lherzolite resulting from the reaction with pyroxenite-derived melt. At 1300 and 1350 ∘C, the reaction produces a thin orthopyroxene-rich reaction zone confined between partially molten pyroxenite and modally unmodified subsolidus lherzolite. Chemical changes in minerals of the pyroxenite crystal mush suggest that element diffusion across the pyroxenite–peridotite interface, coupled with orthopyroxene precipitation, plays a role in the reactive crystallization of mantle pyroxenite veins. At 1380 and 1400 ∘C, infiltration of pyroxenite-derived melt significantly modifies the mineralogy and chemistry of the host peridotite by creating orthopyroxene-rich websterites and pyroxene-rich lherzolite. At 1450 ∘C, pyroxenitic melt fluxes into molten peridotite, enhancing peridotite melting and creating a melt-bearing dunite associated with a refractory harzburgite. At a given pressure, bulk compositions of hybrid rocks originating through melt–peridotite interaction are mostly controlled by the chemistry of the reacting melt. Interaction between pyroxenitic melt and peridotite causes XMg[XMg=Mg/(Mg+Fetot)] and XCr[XCr=Cr/(Cr+Al)] decrease and TiO2 increase in pyroxenes and spinel across the pyroxenite–peridotite boundary. Similar chemical gradients in minerals are observed in pyroxenite–peridotite associations from natural mantle sequences. The comparison with mineral chemistry variations derived by reaction experiments potentially represents a petrologic tool to discriminate between low- versus high-temperature melt–peridotite reactions.
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Renbaum, L. H., and G. D. Smith. "Artifacts in measuring aerosol uptake kinetics: the roles of time, concentration and adsorption." Atmospheric Chemistry and Physics Discussions 11, no. 3 (March 9, 2011): 7971–8002. http://dx.doi.org/10.5194/acpd-11-7971-2011.
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Abstract. In laboratory studies of organic aerosol particles reacting with gas-phase oxidants, high concentrations of radicals are often used to study on the timescale of seconds reactions which may be occurring over days or weeks in the troposphere. Implicit in this approach is the assumption that radical concentration and time are interchangeable parameters, though this has not been established. Here, the kinetics of OH- and Cl-initiated oxidation reactions of model single-component liquid organic aerosols (squalane, brassidic acid and 2-octyldodecanoic acid) are studied by varying separately the radical concentration and the reaction time. Two separate flow tubes with residence times of 2 and 66 s are used, and [OH] and [Cl] are varied by adjusting either the laser photolysis fluence or the radical precursor concentration ([O3] or [Cl2], respectively) used to generate the radicals. It is found that the rates measured by varying the radical concentration and the reaction time are equal only if the precursor concentrations are the same in the two approaches. Further, the rates depend on the concentrations of the precursor species with a Langmuir-type functional form suggesting that O3 and Cl2 saturate the surface of the liquid particles. It is believed that the presence of O3 inhibits the rate of OH reaction, perhaps by reacting with OH radicals or blocking surface sites, while Cl2 enhances the rate of Cl reaction by participating in a radical chain mechanism. These results have important implications for laboratory experiments in which high concentrations of gas-phase oxidants are used to study atmospheric reactions over short timescales and may explain the variability in recent measurements of the reactive uptake of OH on squalane particles in reactor systems used in this and other laboratories.
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Renbaum, L. H., and G. D. Smith. "Artifacts in measuring aerosol uptake kinetics: the roles of time, concentration and adsorption." Atmospheric Chemistry and Physics 11, no. 14 (July 18, 2011): 6881–93. http://dx.doi.org/10.5194/acp-11-6881-2011.
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Abstract. In laboratory studies of organic aerosol particles reacting with gas-phase oxidants, high concentrations of radicals are often used to study on the timescale of seconds reactions which may be occurring over days or weeks in the troposphere. Implicit in this approach is the assumption that radical concentration and time are interchangeable parameters, though this has not been established. Here, the kinetics of OH- and Cl-initiated oxidation reactions of model single-component liquid (squalane) and supercooled (brassidic acid and 2-octyldodecanoic acid) organic aerosols are studied by varying separately the radical concentration and the reaction time. Two separate flow tubes with residence times of 2 and 66 s are used, and [OH] and [Cl] are varied by adjusting either the laser photolysis fluence or the radical precursor concentration ([O3] or [Cl2], respectively) used to generate the radicals. It is found that the rates measured by varying the radical concentration and the reaction time are equal only if the precursor concentrations are the same in the two approaches. Further, the rates depend on the concentrations of the precursor species with a Langmuir-type functional form suggesting that O3 and Cl2 saturate the surface of the liquid particles. It is believed that the presence of O3 inhibits the rate of OH reaction, perhaps by reacting with OH radicals or by O3 or intermediate species blocking surface sites, while Cl2 enhances the rate of Cl reaction by participating in a radical chain mechanism. These results have important implications for laboratory experiments in which high concentrations of gas-phase oxidants are used to study atmospheric reactions over short timescales and may explain the variability in recent measurements of the reactive uptake of OH on squalane particles in reactor systems used in this and other laboratories.
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Barlow, R. S., D. C. Fourguette, M. G. Mungal, and R. W. Dibble. "Experiments on the structure of an annular compressible reacting shear layer." AIAA Journal 30, no. 9 (September 1992): 2244–51. http://dx.doi.org/10.2514/3.11211.
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McHUGH, SEAN T., and SILVANA S. S. CARDOSO. "Turbulent entrainment into inert and reacting multiphase plumes." Journal of Fluid Mechanics 682 (July 15, 2011): 577–89. http://dx.doi.org/10.1017/jfm.2011.246.
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Theoretical predictions and experimental results for turbulent entrainment in inert and reacting, multiphase plumes are presented. It is shown that in an inert, pure plume, the entrainment coefficient is approximately constant with downstream distance. In a reacting plume, in which buoyancy is depleted by chemical reaction, the entrainment coefficient decreases strongly with distance from the source owing mainly to a decrease in the Richardson number. The effect on entrainment of the drift in the velocity and buoyancy distributions in the radial direction, i.e. the similarity drift introduced by Kaminski, Tait & Carazzo (J. Fluid Mech., vol. 526, 2005, pp. 361–76), is found to increase with downstream distance and with the reaction rate but, on laboratory-scale experiments, remains small compared to the contribution to entrainment from the turbulent stresses and buoyancy.
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Antić, V. V., M. P. Antić, M. N. Govedarica, and P. R. Dvornić. "Kinetics of the Formation of Poly(Methyldecylsiloxane) by Hydrosilylation of Poly(Methylhydrosiloxane) and 1-Decene." Materials Science Forum 555 (September 2007): 485–90. http://dx.doi.org/10.4028/www.scientific.net/msf.555.485.
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Poly(methylhydrosiloxane) [PMHS], prepared by siloxane equilibration reaction, was used for the hydrosilylation with 1-decene to obtain poly(methyldecylsiloxane) [PMDS]. Pt(0)-1,3- divinyltetramethyldisiloxane complex was used as a catalyst for hydrosilylation reaction. In order to investigate the kinetics of the formation of PMDS, a series of experiments was performed at different reaction temperatures (from 48 to 64 °C) with catalyst concentrations of 7.0 · 10-7 mol of Pt per mol of CH=CH2. All reactions were carried out in bulk, with equimolar amounts of the reacting Si-H and CH=CH2 groups. The course of the reactions was monitored by following the disappearance of the Si-H bands by quantitative infrared spectroscopy. The obtained results show that an induction period occurs at lower reaction temperatures and that the rate of Si-H conversion follows the first-order kinetics.
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Aguilar-López, Ricardo. "Chaos Suppression via Euler-Lagrange Control Design for a Class of Chemical Reacting System." Mathematical Problems in Engineering 2018 (December 30, 2018): 1–6. http://dx.doi.org/10.1155/2018/3802801.
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In this work the problem of chaos suppression for a class of continuous chemical reactor with chaotic dynamics is tackled via a nonlinear control strategy. The proposed controller is developed under the framework of optimal control theory, where a functional is proposed to maximize the chemical reaction rate via a proposed Lagrangian-type which contains directly the state equation of the reacting system, avoiding the problems of Lagrange, the Hamiltonian formulation, and consequently the explicit constraints to the system. This allows solving in an easier form the optimization problem in comparison with the standard methods. This procedure allows suppressing the chaotic behavior of the reacting system by stabilizing the reaction rate term by leading it to an extreme value. Numerical experiments are done in order to show the satisfactory performance of the proposed methodology.
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Mizane, Abbes, Ahmed Boumerah, Noureddine Dadda, Rabah Rehamnia, and Salah Belhait. "Obtaining the partially acidulated phosphate rocks by means of intermediate-grade phosphate and diluted phosphoric acid: Influence of some parameters." Polish Journal of Chemical Technology 18, no. 3 (September 1, 2016): 39–43. http://dx.doi.org/10.1515/pjct-2016-0046.
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Abstract In this work, some parameters during the partial acidulation by phosphoric acid of phosphate 53.75% BPL (bone phosphate of lime) having different particle sizes are determined. P2O5 recovery is obtained by performing a series of reactions using phosphoric acid diluted from 10 to 40 wt.% and with reaction times ranging from 10 to 50 minutes. The best conversion rates are obtained with the following reaction parameters: phosphates size: 88-177 μm, reaction time: 50 minutes and phosphoric acid concentration: 40 wt.%. In the second part, the water-soluble P2O5 of PAPRs (Partially Acidulated Phosphate Rocks) obtained with phosphoric acid 30% and 40 wt.% is measured. The results of experiments showed that the water-soluble P2O5 has reached 15.2% for PAPRs obtained by reacting phosphate 88 μm with phosphoric acid 40 wt%.
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Zhang, Yongli, and Ruiting Li. "Effect of Reaction Temperature on Adsorption Efficiency using Computer Mathematical Statistics Visible Spectorphotometer." Journal of Physics: Conference Series 2083, no. 3 (November 1, 2021): 032072. http://dx.doi.org/10.1088/1742-6596/2083/3/032072.
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Abstract In this paper, waste shrimp shells extracted from the head of the chitosan material; static adsorption experiments manner by wastewater containing Fe(III) added chitosan, vis spectrophotometer absorbance before and after the measurement experiment was obtained by reacting the size of the metal ion concentration, adsorption conditions whereby chitosan Fe(III) and the ability to explore. Experiments show that. In the case where the reaction temperature is less than 55°C, chitosan has adsorption rate Fe(III) smaller rise, the optimum temperature was 55°C, but the effects on the reaction temperature adsorption rate is not large; Adsorption when control time 30 min to 50 min, the absorption effect is increased with increase in the time, to reach the optimal reaction time 50 min.
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SLESSOR, M. D., C. L. BOND, and P. E. DIMOTAKIS. "Turbulent shear-layer mixing at high Reynolds numbers: effects of inflow conditions." Journal of Fluid Mechanics 376 (December 10, 1998): 115–38. http://dx.doi.org/10.1017/s0022112098002857.
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We report on the results from a set of incompressible, shear-layer flow experiments, at high Reynolds number (Reδ≡ρΔUδT(x)/ μ≃2×105), in which the inflow conditions of shear-layer formation were varied (δT is the temperature-rise thickness for chemically-reacting shear layers). Both inert and chemically-reacting flows were investigated, the latter employing the (H2+NO)/F2 chemical system in the kinetically-fast regime to measure molecular mixing. Inflow conditions were varied by perturbing each, or both, boundary layers on the splitter plate separating the two freestream flows, upstream of shear-layer formation. The results of the chemically-reacting ‘flip experiments’ reveal that seemingly small changes in inflow conditions can have a significant influence not only on the large-scale structure and shear-layer growth rate, as had been documented previously, but also on molecular mixing and chemical-product formation, far downstream of the inflow region.
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Chu, Biwu, Yali Wang, Weiwei Yang, Jinzhu Ma, Qingxin Ma, Peng Zhang, Yongchun Liu, and Hong He. "Effects of NO<sub>2</sub> and C<sub>3</sub>H<sub>6</sub> on the heterogeneous oxidation of SO<sub>2</sub> on TiO<sub>2</sub> in the presence or absence of UV–Vis irradiation." Atmospheric Chemistry and Physics 19, no. 23 (December 9, 2019): 14777–90. http://dx.doi.org/10.5194/acp-19-14777-2019.
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Abstract. The heterogeneous reactions of SO2 in the presence of NO2 and C3H6 on TiO2 were investigated with the aid of in situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) under dark conditions or with UV–Vis irradiation. Sulfate formation with or without the coexistence of NO2 and/or C3H6 was analyzed with ion chromatography (IC). Under dark conditions, SO2 reacting alone resulted in sulfite formation on TiO2, while the presence of parts per billion (ppb) levels of NO2 promoted the oxidation of SO2 to sulfate. The presence of C3H6 had little effect on sulfate formation in the heterogeneous reaction of SO2 but suppressed sulfate formation in the heterogeneous reaction of SO2 and NO2. UV–Vis irradiation could significantly enhance the heterogeneous oxidation of SO2 on TiO2, leading to copious generation of sulfate, while the coexistence of NO2 and/or C3H6 significantly suppressed sulfate formation in experiments with UV–Vis lights. Step-by-step exposure experiments indicated that C3H6 mainly competes for reactive oxygen species (ROS), while NO2 competes with SO2 for both surface active sites and ROS. Meanwhile, the coexistence of NO2 with C3H6 further resulted in less sulfate formation compared to introducing either one of them separately to the SO2–TiO2 reaction system. The results of this study highlighted the complex heterogeneous reaction processes that take place due to the ubiquitous interactions between organic and inorganic species and the need to consider the influence of coexisting volatile organic compounds (VOCs) and other inorganic gases in the heterogeneous oxidation kinetics of SO2.
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Vleeschhouwer, P. H. M., and J. M. H. Fortuin. "Theory and experiments concerning the stability of a reacting system in a CSTR." AIChE Journal 36, no. 6 (June 1990): 961–65. http://dx.doi.org/10.1002/aic.690360621.
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Andrzejewski, P., and J. Nawrocki. "N-nitrosodimethylamine formation during treatment with strong oxidants of dimethylamine containing water." Water Science and Technology 56, no. 12 (December 1, 2007): 125–31. http://dx.doi.org/10.2166/wst.2007.802.
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The aim of the paper is the evaluation of the possibility of NDMA formation, as a result of strong oxidants reacting with DMA. Summarized results of investigations on N-nitrosodimethylamine formation as a result of dimethylamine reactions with chlorine dioxide, ozone and hydrogen peroxide are presented. Preliminary results of experiments on NDMA formation as a result of DMA reactions with permanganate are also shown. The experiments on dimethylamine reactions with chlorine dioxide, hydrogen peroxide and permanganate were carried out at room temperature under static conditions. Ozonation experiments were carried out at room temperature in a semi-continuous mode. Water samples from all experiments described above were collected during the experiment itself and subsequently analyzed with HPLC-IE with UV-Vis detector at 230 nm. NDMA formation was also confirmed by GC-LRMS. NDMA forms as a result of chlorine dioxide, ozone, hydrogen peroxide or permanganate reactions with dimethylamine. both in the presence as well as in the absence of ammonia ions. The presence of nitrites and nitrates in a post-reaction mixture suggests that NDMA are formed as the result of DMA reactions with nitrites. Thus the mechanism of NDMA formation with these oxidants is different than that described by Mitch et al. and Choi et al. The results also showed a conversion ratio of DMA to NDMA of even up to a single percent (with relation to amines), a simultaneous decrease of NDMA formation potential with a decrease of pH, however, in the case of chlorine dioxide application, a maximum conversion ratio was observed, as well the NDMA formation potential is strongly dependent on the oxidant/DMA ratio.
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Patel, Arth, Paige N. Smith, Alan J. Russell, and Sheiliza Carmali. "Automated prediction of site and sequence of protein modification with ATRP initiators." PLOS ONE 17, no. 9 (September 19, 2022): e0274606. http://dx.doi.org/10.1371/journal.pone.0274606.
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One of the most straightforward and commonly used chemical modifications of proteins is to react surface amino groups (lysine residues) with activated esters. This chemistry has been used to generate protein-polymer conjugates, many of which are now approved therapeutics. Similar conjugates have also been generated by reacting activated ester atom transfer polymerization initiators with lysine residues to create biomacromolecular initiators for polymerization reactions. The reaction between activated esters and lysine amino groups is rapid and has been consistently described in almost every publication on the topic as a “random reaction”. A random reaction implies that every accessible lysine amino group on a protein molecule is equally reactive, and as a result, that the reaction is indiscriminate. Nonetheless, the literature contradicts itself by also suggesting that some lysine amino groups are more reactive than others (as a function of pKa, surface accessibility, temperature, and local environment). If the latter assumption is correct, then the outcome of these reactions cannot be random at all, and we should be able to predict the outcome from the structure of the protein. Predicting the non-random outcome of a reaction between surface lysines and reactive esters could transform the speed at which active bioconjugates can be developed and engineered. Herein, we describe a robust integrated tool that predicts the activated ester reactivity of every lysine in a protein, thereby allowing us to calculate the non-random sequence of reaction as a function of reaction conditions. Specifically, we have predicted the intrinsic reactivity of each lysine in multiple proteins with a bromine-functionalised N-hydroxysuccinimide initiator molecule. We have also shown that the model applied to PEGylation. The rules-based analysis has been coupled together in a single Python program that can bypass tedious trial and error experiments usually needed in protein-polymer conjugate design and synthesis.
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Bergamasco, R., DHS Horn, RH Nearn, and JS Wilkie. "Insect Moulting Hormones. LV. Experiments Directed Towards the Synthesis of Non-steroidal Ecdysone Analogues." Australian Journal of Chemistry 38, no. 3 (1985): 475. http://dx.doi.org/10.1071/ch9850475.
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Exploratory studies aimed at the synthesis of the non-steroidal ecdysone analogue (4aR,7S,8aR,-1′RS,4′R)-7-hydroxy-3-(1′-hydroxy-4′,8′- dimethylnonyl )-4a-methyl-4a,5,6,7,8,8a-hexahydronaphthal-en- 1(4H)-one (3) have led to in efficient method of joining the cyclic and side-chain synthons by reacting the vinylogous ester (4a) with 1-lithio-4,8-dimethyl-1,1-bis( methylthio ) nonane (12) to yield (4′RS)-3- [4′,8′-dimethyl-1′,1′-bis( methylthio ) nonyl ]-5,5-dimethylcyclohex-2-en-1-one (13). This thioacetal on reaction with boron trifluoride etherate and mercuric oxide afforded, quantitatively, the diketone (4′RS)-3-(4′,8′-dimethyl-1′-oxononyl)-5,5-dimethylcyclohex-2-en-1-one (14) which was selectively reduced in 85% yield to the required model compound (4′RS)-3-(1′-hydroxy-4′,8′-dimethylnonyl)-5,5-dimethylcyclohex-2-en-1-one (15).
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Xiong, Meng, Cheng Xi Wang, and Dan Dan Shao. "Preparing Sodium Methoxide from Sodium Hydroxide by Reaction Coupling with Separation Processes." Advanced Materials Research 986-987 (July 2014): 101–5. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.101.
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Preparing sodium methoxide by reacting sodium hydroxide with methanol was investigated. The chemical equilibrium constant was small. Removing water out of the reaction phase could drive the reaction to produce more sodium methoxide. The experiments were carried out at different temperatures and 1 atm in semi-batch reactor by liquid evaporating to remove water. The effects of initial sodium hydroxide concentration and liquid evaporating speed were discussed. A mathematical model coupling reaction with separation processes was built and the predicted results by the model were in good agreement with experiment results. The model provides useful information for industrial simulation.
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Henry, Michael M., Stephen Thomas, Mone’t Alberts, Carla E. Estridge, Brittan Farmer, Olivia McNair, and Eric Jankowski. "General-Purpose Coarse-Grained Toughened Thermoset Model for 44DDS/DGEBA/PES." Polymers 12, no. 11 (October 30, 2020): 2547. http://dx.doi.org/10.3390/polym12112547.
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The objective of this work is to predict the morphology and material properties of crosslinking polymers used in aerospace applications. We extend the open-source dybond plugin for HOOMD-Blue to implement a new coarse-grained model of reacting epoxy thermosets and use the 44DDS/DGEBA/PES system as a case study for calibration and validation. We parameterize the coarse-grained model from atomistic solubility data, calibrate reaction dynamics against experiments, and check for size-dependent artifacts. We validate model predictions by comparing glass transition temperatures measurements at arbitrary degree of cure, gel-points, and morphology predictions against experiments. We demonstrate for the first time in molecular simulations the cure-path dependence of toughened thermoset morphologies.
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BERGTHORSON, JEFFREY M., SEAN D. SALUSBURY, and PAUL E. DIMOTAKIS. "Experiments and modelling of premixed laminar stagnation flame hydrodynamics." Journal of Fluid Mechanics 681 (June 23, 2011): 340–69. http://dx.doi.org/10.1017/jfm.2011.203.
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The hydrodynamics of a reacting impinging laminar jet, or stagnation flame, is studied experimentally and modelled using large activation energy asymptotic models and numerical simulations. The jet-wall geometry yields a stable, steady flame and allows for precise measurement and specification of all boundary conditions on the flow. Laser diagnostic techniques are used to measure velocity and CH radical profiles. The axial velocity profile through a premixed stagnation flame is found to be independent of the nozzle-to-wall separation distance at a fixed nozzle pressure drop, in accord with results for non-reacting impinging laminar jet flows, and thus the strain rate in these flames is only a function of the pressure drop across the nozzle. The relative agreement between the numerical simulations and experiment using a particular combustion chemistry model is found to be insensitive to both the strain rate imposed on the flame and the relative amounts of oxygen and nitrogen in the premixed gas, when the velocity boundary conditions on the simulations are applied in a manner consistent with the formulation of the streamfunction hydrodynamic model. The analytical model predicts unburned, or reference, flame speeds that are slightly lower than the detailed numerical simulations in all cases and the observed dependence of this reference flame speed on strain rate is stronger than that predicted by the model. Experiment and simulation are in excellent agreement for near-stoichiometric methane–air flames, but deviations are observed for ethylene flames with several of the combustion models used. The discrepancies between simulation and experimental profiles are quantified in terms of differences between measured and predicted reference flame speeds, or position of the CH-profile maxima, which are shown to be directly correlated. The direct comparison of the measured and simulated reference flame speeds, ΔSu, can be used to infer the difference between the predicted flame speed of the combustion model employed and the true laminar flame speed of the mixture, ΔSOf, i.e. ΔSu=ΔSOf, consistent with recently proposed nonlinear extrapolation techniques.
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VERDON, JAMES, and ANDREW W. WOODS. "Gravity-driven reacting flows in a confined porous aquifer." Journal of Fluid Mechanics 588 (September 24, 2007): 29–41. http://dx.doi.org/10.1017/s0022112007007069.
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We develop a model for the dynamics of a reactive gravity-driven flow in a porous layer of finite depth, accounting for the change in permeability and density across the dissolution front. We identify that the two controlling parameters are the mobility ratio across the reaction front and the ratio of the buoyancy-driven flow to the fluid injection rate. We present some numerical solutions for the evolution of a two-dimensional dissolution front, and develop an approximate analytic solution for the limit of large injection rate compared to the buoyancy-driven flow. The model predictions are compared with some new analogue laboratory experiments in which fresh water displaces a saturated aqueous solution initially confined within a two-dimensional reactive permeable matrix composed of salt powder and glass ballotini. We also present self-similar solutions for an axisymmetric gravity-driven reactive current moving through a porous layer of finite depth. The solutions illustrate how the reaction front becomes progressively wider as the ratio of the buoyancy-driven flow to the injection rate increases, and also as the mobility contrast across the front increases.
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Shi, Lisheng, Jiayan Ge, Shuangxi Nie, Chengrong Qin, and Shuangquan Yao. "Effect of lignin structure on adsorbable organic halogens formation in chlorine dioxide bleaching." Royal Society Open Science 6, no. 2 (February 2019): 182024. http://dx.doi.org/10.1098/rsos.182024.
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Adsorbable organic halogens (AOX) are formed in pulp bleaching as a result of the reaction of residual lignin with chlorine dioxide. The natural structure of lignin is very complex and it tends to be damaged by various extraction methods. All the factors can affect the study about the mechanism of AOX formation in the reaction of lignin with chlorine dioxide. Lignin model compounds, with certain structures, can be used to study the role of different lignin structures on AOX formation. The effect of lignin structure on AOX formation was determined by reacting phenolic and non-phenolic lignin model compound with a chlorine dioxide solution. Vanillyl alcohol (VA) and veratryl alcohol (VE) were selected for the phenolic and non-phenolic lignin model compound, respectively. The pattern consumption of lignin model compounds suggests that both VA and VE began reacting with chlorine dioxide within 10 min and then gradually steadied. The volume of AOX produced by VE was significantly higher than that produced by VA for a given initial lignin model compound concentration. In a solution containing a combination of VA and VE in chlorine dioxide, VE was the dominant producer of AOX. This result indicates that the non-phenolic lignin structure was more easily chlorinated, while the phenolic lignin structure was mainly oxidized. In addition, AOX content produced in the combined experiments exceeded the total content of the two separate experiments. It suggested that the combination of phenolic and non-phenolic lignin structure can promote AOX formation.
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Eykyn, Thomas R., Stuart J. Elliott, and Philip W. Kuchel. "Extended Bloch–McConnell equations for mechanistic analysis of hyperpolarized <sup>13</sup>C magnetic resonance experiments on enzyme systems." Magnetic Resonance 2, no. 1 (June 15, 2021): 421–46. http://dx.doi.org/10.5194/mr-2-421-2021.
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Abstract. We describe an approach to formulating the kinetic master equations of the time evolution of NMR signals in reacting (bio)chemical systems. Special focus is given to studies that employ signal enhancement (hyperpolarization) methods such as dissolution dynamic nuclear polarization (dDNP) and involving nuclear spin-bearing solutes that undergo reactions mediated by enzymes and membrane transport proteins. We extend the work given in a recent presentation on this topic (Kuchel and Shishmarev, 2020) to now include enzymes with two or more substrates and various enzyme reaction mechanisms as classified by Cleland, with particular reference to non-first-order processes. Using this approach, we can address some pressing questions in the field from a theoretical standpoint. For example, why does binding of a hyperpolarized substrate to an enzyme not cause an appreciable loss of the signal from the substrate or product? Why does the concentration of an unlabelled pool of substrate, for example 12C lactate, cause an increase in the rate of exchange of the 13C-labelled pool? To what extent is the equilibrium position of the reaction perturbed during administration of the substrate? The formalism gives a full mechanistic understanding of the time courses derived and is of relevance to ongoing clinical trials using these techniques.
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Stewart, P. S. "Theoretical aspects of antibiotic diffusion into microbial biofilms." Antimicrobial Agents and Chemotherapy 40, no. 11 (November 1996): 2517–22. http://dx.doi.org/10.1128/aac.40.11.2517.
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Antibiotic penetration into microbial biofilm was investigated theoretically by the solution of mathematical equations describing various combinations of the processes of diffusion, sorption, and reaction. Unsteady material balances on the antibiotic and on a reactive or sorptive biomass constituent, along with associated boundary and initial conditions, constitute the mathematical formulations. Five cases were examined: diffusion of a noninteracting solute; diffusion of a reversibly sorbing, nonreacting solute; diffusion of an irreversibly sorbing, nonreacting solute; diffusion of a stoichiometrically reacting solute; and diffusion of a catalytically reacting solute. A noninteracting solute was predicted to penetrate biofilms of up to 1 mm in thickness relatively quickly, within a matter of seconds or minutes. In the case of a solute that does not sorb or react in the biofilm, therefore, the diffusion barrier is not nearly large enough to account for the reduced susceptibility of biofilms to antibiotics. Reversible and irreversible sorption retards antibiotic penetration. On the basis of data available in the literature at this point, the extent of retardation of antibiotic diffusion due to sorption does not appear to be sufficient to account for reduced biofilm susceptibility. A catalytic (e.g., enzymatic) reaction, provided it is sufficiently rapid, can lead to severe antibiotic penetration failure. For example, calculation of beta-lactam penetration indicated that the reaction-diffusion mechanism may be a viable explanation for failure of certain of these agents to control biofilm infections. The theory presented in this study provides a framework for the design and analysis of experiments to test these mechanisms of reduced biofilm susceptibility to antibiotics.
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NAGATA, KOUJI, and SATORU KOMORI. "The effects of unstable stratification and mean shear on the chemical reaction in grid turbulence." Journal of Fluid Mechanics 408 (April 10, 2000): 39–52. http://dx.doi.org/10.1017/s0022112099007594.
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The effects of unstable thermal stratification and mean shear on chemical reaction and turbulent mixing were experimentally investigated in reacting and non-reacting liquid mixing-layer flows downstream of a turbulence-generating grid. Experiments were carried out under three conditions: unsheared neutrally stratified, unsheared unstably stratified and sheared neutrally stratified. Instantaneous velocity and concentration were simultaneously measured using the combination of a laser-Doppler velocimeter and a laser-induced fluorescence technique. The results show that the turbulent mixing is enhanced at both large and small scales by buoyancy under unstably stratified conditions and therefore the chemical reaction is strongly promoted. The mean shear acts to enhance the turbulent mixing mainly at large scales. However, the chemical reaction rate in the sheared flow is not as large as in the unstably stratified case with the same turbulence level, since the mixing at small scales in the sheared neutrally stratified flow is weaker than that in the unsheared unstably stratified flow. The unstable stratification is regarded as a better tool to attain unsheared mixing since the shearing stress acting on the fluid is much weaker in the unstably stratified flow than in the sheared flow.
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Muppala, Siva, and Vendra C. Madhav Rao. "Numerical Implementation and validation of turbulent premixed combustion model for lean mixtures." MATEC Web of Conferences 209 (2018): 00004. http://dx.doi.org/10.1051/matecconf/201820900004.
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The present paper discusses the numerical investigation of turbulent premixed flames under lean conditions. Lean premixed combustion, a low NOx emission technique but are prone to instabilities, extinction and blow out. Such flames are influenced by preferential diffusion due to different mass diffusivities of reactants and difference between heat and mass diffusivities in the reaction zone. In this numerical study, we estimate non-reacting flow characteristics with implementation of an Algebraic Flame Surface Wrinkling Model (AFSW) in the open source CFD code OpenFOAM. In these flows, the mean velocity fields and recirculation zones were captured reasonably well by the RANS standard k-epsilon turbulence model. The simulated turbulent velocity is in good agreement with experiments in the shear-generated turbulence layer. The reacting flow study was done at three equivalence ratios of 0.43, 0.5 and 0.56 to gauge the ability of numerical model to predict combustion quantities. At equivalence ratios 0.5 and 0.56 the simulations showed numerical oscillations and non-convergence of the turbulent quantities. This leads to a detailed parametric variation study where, the pre-constant of AFSW model is varied with values 0.3, 0.35 and 0.4. However the study revealed the weak dependence of pre-constant value on the equivalence ratio. Hence the pre-constant value is fit for specific equivalence ratio based on the parametric variation study. The tuned AFSW model with fitted pre-constant specific to given equivalence ratio predicted are compared with experiments and discussed. The tuned AFSW model produced turbulent flame speed values which are good agreement with experiments.
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Foley, Stephen, and Maik Pertermann. "Dynamic Metasomatism Experiments Investigating the Interaction between Migrating Potassic Melt and Garnet Peridotite." Geosciences 11, no. 10 (October 18, 2021): 432. http://dx.doi.org/10.3390/geosciences11100432.
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Dynamic metasomatism experiments were performed by reacting a lamproite melt with garnet peridotite by drawing melt through the peridotite into a vitreous carbon melt trap, ensuring the flow of melt through the peridotite and facilitating analysis of the melt. Pressure (2–3 GPa) and temperature (1050–1125 °C) conditions were chosen where the lamproite was molten but the peridotite was not. Phlogopite was formed and garnet and orthopyroxene reacted out, resulting in phlogopite wehrlite (2 GPa) and phlogopite harzburgite (3 GPa). Phlogopites in the peridotite have higher Mg/(Mg + Fe) and Cr2O3 and lower TiO2 than in the lamproite due to buffering by peridotite minerals, with Cr2O3 from the elimination of garnet. Compositional trends in phlogopites in the peridotite are similar to those in natural garnet peridotite xenoliths in kimberlites. Changes in melt composition resulting from the reaction show decreased TiO2 and increased Cr2O3 and Mg/(Mg + Fe). The loss of phlogopite components during migration through the peridotite results in low K2O/Na2O and K/Al in melts, indicating that chemical characteristics of lamproites are lost through reaction with peridotite so that emerging melts would be less extreme in composition. This indicates that lamproites are unlikely to be derived from a source rich in peridotite, and more likely originate in a source dominated by phlogopite-rich hydrous pyroxenites. Phlogopites from an experiment in which lamproite and peridotite were intimately mixed before the experiment did not produce the same phlogopite compositions, showing that care must be taken in the design of reaction experiments.
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K Standish, Russell. "Motion of Charged Particles in a Homogeneous Reacting Medium with a One-dimensional Geometry." Australian Journal of Physics 42, no. 3 (1989): 223. http://dx.doi.org/10.1071/ph890223.
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We study the approach to steady state of a system described by the Klein-Kramers equation with a COnstant source, to see how the source structure effects disappear away from the source. We link this to some earlier work on non-hydrodynamic effects in time-of-flight swarm experiments to show how this theory may be applied to the analysis of steady-state Townsend swarm experiments.
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Koochesfahani, M. M., and P. E. Dimotakis. "Mixing and chemical reactions in a turbulent liquid mixing layer." Journal of Fluid Mechanics 170 (September 1986): 83–112. http://dx.doi.org/10.1017/s0022112086000812.
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An experimental investigation of entrainment and mixing in reacting and non-reacting turbulent mixing layers at large Schmidt number is presented. In non-reacting cases, a passive scalar is used to measure the probability density function (p.d.f.) of the composition field. Chemically reacting experiments employ a diffusion-limited acid–base reaction to directly measure the extent of molecular mixing. The measurements make use of laser-induced fluorescence diagnostics and high-speed, real-time digital image-acquisition techniques.Our results show that the vortical structures in the mixing layer initially roll-up with a large excess of fluid from the high-speed stream entrapped in the cores. During the mixing transition, not only does the amount of mixed fluid increase, but its composition also changes. It is found that the range of compositions of the mixed fluid, above the mixing transition and also throughout the transition region, is essentially uniform across the entire transverse extent of the layer. Our measurements indicate that the probability of finding unmixed fluid in the centre of the layer, above the mixing transition, can be as high as 0.45. In addition, the mean concentration of mixed fluid across the layer is found to be approximately constant at a value corresponding to the entrainment ratio. Comparisons with gas-phase data show that the normalized amount of chemical product formed in the liquid layer, at high Reynolds number, is 50% less than the corresponding quantity measured in the gas-phase case. We therefore conclude that Schmidt number plays a role in turbulent mixing of high-Reynolds-number flows.
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Buffo, A., M. Vanni, and D. L. Marchisio. "Simulation of a reacting gas–liquid bubbly flow with CFD and PBM: Validation with experiments." Applied Mathematical Modelling 44 (April 2017): 43–60. http://dx.doi.org/10.1016/j.apm.2016.11.010.
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Fulachier, L., R. Borghi, F. Anselmet, and P. Paranthoen. "Influence of density variations on the structure of low-speed turbulent flows: a report on Euromech 237." Journal of Fluid Mechanics 203 (June 1989): 577–93. http://dx.doi.org/10.1017/s0022112089001606.
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The European Mechanics Colloquium number 237 was held at the Institut de Mécanique Statistique de la Turbulence (Université d'Aix-Marseille II) from 18 to 21 July 1988. This was the first meeting to consider the influence of density variations on turbulent flows for both non-reacting and reacting flows in a variety of configurations. Several new experiments, computational models and theoretical analyses were presented for non-reacting flows. All these approaches showed the marked effects of density variations on coherent structures in turbulent shear flows. It was found that the approximate models used for turbulent Reynolds stresses in homogeneous flows do not need to be changed for the mean flow field but predictions for variances and correlations are still rather uncertain: in fact experimental results providing such information in variable-density flows are rare. The special problem of measuring turbulence in flows with density variations was discussed. In the discussions it was agreed that there are in fact strong similarities in the effects of density gradients on the dynamics of non-reacting flows and reacting flows despite the differences in the distributions of density gradients. Participants at the meeting from industry emphasized the importance of these flows to many different kinds of industrial and environmental problems.
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Zhao, Yong, and Jian Sheng Zhang. "Determination of Char-CO2 Gasification Rate through Reaction Product." Advanced Materials Research 953-954 (June 2014): 1026–30. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.1026.
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This paper presents gasification kinetic parameters generated for Japanese lignite coal char reacting with carbon dioxide and the method for obtaining them. The experiments were conducted in a PTGA at atmospheric pressure within a temperature range of 1148K-1223K, and a mass spectrometer (MS) is coupled with PTGA to obtain the concentrations of product gas. The experiments were carried out with isothermal method, and kinetic parameters were determined through the analysis of the weight changes of coal char and the concentrations of products respectively. The effect of CO2 partial pressure on reaction rate was analyzed by nth order rate equation. It was found that the activation energy of char-CO2 reaction obtained from weight loss curve and product concentrations were 187.9kJ/mol and 187.0kJ/mol respectively, and the reaction order n were 0.24 and 0.222, proving MS a feasible method for kinetics research. Through the comparison, the method to obtain the kinetic data by concentrations of gas products was determined, and a more clear understanding of the gasification process was established.
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Phelan, Dominic. "Influence of Undercooling on the Kinetics of the Peritectic Transition in an Fe-4.2wt%Ni Alloy." Materials Science Forum 649 (May 2010): 143–47. http://dx.doi.org/10.4028/www.scientific.net/msf.649.143.
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In-situ Laser Scanning Confocal Microscopy observations are presented that assess the influence of undercooling before the initiation of the peritectic transition in a Fe-4.2wt%Ni alloy on the resulting kinetics of the peritectic reaction and transformation. In a series of experiments varying the cooling rate, increasing the cooling rate led to a lower temperature at the L/ interface. The resulting peritectic reaction changed from slow 840m/s - 1500m/s, with limited growth into the to rapid ~11mm/s with significant growth into . In continuous cooling experiments when the nucleation temperature was low, growth into was high and the reacting species was observed to propagate along the liquid/delta-ferrite interface at a rate of ~11mm/s. The peritectic reaction rate did not appear to be a function of temperature over a measured nucleation temperature range of 5 K. Conversely, the growth rate of austenite into the delta-ferrite in the first 0.03 seconds was observed to increase from 1.5mm/s to 8mm/s as the measured temperature at nucleation decreased.
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Boros, Lech. "Evaluation of Stability of Field Pea genotypes in response to Mycosphaerella Pinodes Infection." Plant Breeding and Seed Science 65, no. 1 (August 8, 2014): 79–85. http://dx.doi.org/10.2478/v10129-011-0050-x.
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Abstract Interaction of genotypes with environment for quantitative traits among them certain disease resistance makes difficult choice of proper genotypes for breeding proposes and may affects further cultivation effects. The aim of this study was assessment of stability of reaction to Mycosphaerella pinodes infection for the set of pea genotypes in four years field experiments with vary epidemic pressure. The Sheffé-Caliński mixed model and the Caliński-Kaczmarek joint regression model for genotype-environment interaction analysis was applied. Tested pea genotypes were grouped into two categories; responding stable to M. pinodes (reacting proportionally to changed environment) and unstable ones (showing significant interaction with environment). The unstable genotypes reacted irregularly to environments (not able to describe the reaction to M. pinodes by any linear regression function). Pea genotypes PI 142441, PI 142442, PI 404221, PI 413691, cv. Radley and Bohun were characterized by high negative main effects (most resistant) for disease severity and showed stable response to M. pinodes infection. Stability of mycospharealla blight reactions was not associated with the level of resistance in the cultivars tested.
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Ryding, M. J., Å. M. Jonsson, A. S. Zatula, P. U. Andersson, and E. Uggerud. "Reactions of H<sup>+</sup>(pyridine)<sub><i>m</i></sub>(H<sub>2</sub>O)<sub><i>n</i></sub> and H<sup>+</sup>(NH<sub>3</sub>)<sub>1</sub>(pyridine)<sub>1</sub>(H<sub>2</sub>O)<sub><i>n</i></sub> with NH<sub>3</sub>: experiments and kinetic modelling under tropospheric conditions." Atmospheric Chemistry and Physics Discussions 11, no. 9 (September 1, 2011): 24535–66. http://dx.doi.org/10.5194/acpd-11-24535-2011.
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Abstract. Reactions between pyridine containing water cluster ions, H+(pyridine)1(H2O)n, H+(pyridine)2(H2O)n and H+(NH3)1(pyridine)1(H2O)n (n up to 15) with NH3 have been studied experimentally using a quadrupole time-of-flight mass spectrometer. The product ions in the reaction between H+(pyridine)m(H2O)n and NH3 have been determined for the first time. It is found that the reaction mainly leads to cluster ions of the form HH+(NH3)1(pyridine)1(H2O)n−x, with x = 1 or 2 depending on the initial size of the reacting cluster ion. For a given number of water molecules (from 5 to 15) in the cluster ion, rate coefficients are found to be slightly lower than those for protonated pure water clusters reacting with ammonia. The rate coefficients obtained from this study are used in a kinetic cluster ion model under tropospheric conditions. The results from the model suggest that cluster ions containing ammonia and more than one pyridine, picoline or lutidine molecule should dominate at ground level under typical conditions.
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Cao, Weiming, and Borries Demeler. "Modeling Analytical Ultracentrifugation Experiments with an Adaptive Space-Time Finite Element Solution for Multicomponent Reacting Systems." Biophysical Journal 95, no. 1 (July 2008): 54–65. http://dx.doi.org/10.1529/biophysj.107.123950.
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Pawelec, G., N. Fernandez, T. Brocker, E. M. Schneider, H. Festenstein, and P. Wernet. "DY determinants, possibly associated with novel class II molecules, stimulate autoreactive CD4+ T cells with suppressive activity." Journal of Experimental Medicine 167, no. 2 (February 1, 1988): 243–61. http://dx.doi.org/10.1084/jem.167.2.243.
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A set of T cell clones (TCC) isolated from HLA-DR-, Dw-, DQ-matched allogeneic MLCs was found to proliferate autonomously when stimulated with cells carrying a wide range of class I or II specificities. This apparently unrestricted proliferation was relatively weak, and only low levels of IL-2 were present in the supernatants of stimulated cells. Autologous as well as allogeneic PBMC and B lymphoblastoid cell lines (B-LCL) were capable of stimulating such clones, which were also restimulated by suppressive, but not by helper, TCC. Moreover, such clones displayed the unusual property of autostimulation. mAb inhibition experiments suggested that class II- or class II-restricted antigens were involved in stimulation. Thus, certain "broad" mAbs (TU39, SG520) reacting with multiple locus products inhibited activation of these reagents, but none of those reacting more specifically with DR (TU34, TU37, L243, Q2/70, SG157), DQ (TU22, SPV-L3, Leu 10), or DP (B7/21), or mixtures of these mAbs, were able to do so. Evidence from sequential immunoprecipitation experiments suggested that mAb TU39 bound class II-like molecules other than DR, DQ, and DP on TCC and B-LCL, and it is therefore proposed that such putative novel class II-like molecules may carry the stimulating determinants for these autoreactive clones. DY-reactive clones lacked helper activity for B cells but mediated potent suppressive activity on T cell proliferative responses that was not restricted by the HLA type of the responding cells. Suppressive activity was induced in normal PBMC by such clones, as well as by independent suppressive clones, which was also inhibited only by mAb TU39. These findings lead to the proposal that DY-reactive autostimulatory cells may constitute a self-maintaining suppressive circuit, the level of activity of which would be regulated primarily by the availability of IL-2 in the microenvironment.
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Rochelle, C. A., A. E. Milodowski, K. Bateman, E. B. A. Moyce, and A. Kilpatrick. "A long-term experimental study of the reactivity of basement rock with highly alkaline cement waters: Reactions over the first 15 months." Mineralogical Magazine 80, no. 6 (October 2016): 1089–113. http://dx.doi.org/10.1180/minmag.2016.080.056.
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AbstractA series of long-term laboratory experiments was started in 1995 to investigate longer-term dissolution/ precipitation reactions that may occur in the alkaline disturbed zone surrounding a cementitious repository for radioactive waste. They consist of samples of UK basement rock reacting with either Na-K-Ca-OH water ('young' cement porewater) or Ca-OH water ('evolved' cement porewater) at 70°C. This paper summarizes results of reactions occurring over the first 15 months. Experiments of both fluid types showed many similar features, though primary mineral dissolution and secondary mineral precipitation were more extensive in the experiments involving Na-K-Ca (younger) cement porefluids compared to more evolved (Ca-rich) cement porefluids. Dissolution of dolomite, and to a lesser extent silicates (probably K-feldspar, but also possibly mica) occurred relatively rapidly at 70°C. Dolomite dissolution may have been a key factor in reducing pH values, and may be a key mineral in controlling the extent of alkaline disturbed zones. Dissolution was followed by precipitation of brucite close to dolomite grains, at least two generations of C-S-H phases (which may have contained variable amounts of K, Al and Mg); overgrowths of calcite; small crystals of hydroxyapophyllite; and elongate crystals of celestite. Though hydroxyapophyllite was observed (a phase commonly associated with zeolites), there was no evidence for the formation of zeolites in the experiments. Fluid chemical changes track the mineralogical changes, with C-S-H phases being a major control on fluid chemistry. In the 'young' porewater experiments there were decreases in pH, and K, Ca and Mg concentrations, together with transitory increases in SiO2concentrations. In the 'evolved' porewater experiments there were decreases in pH, Mg, Ca and Sr concentrations, together with small increases in K and SiO2concentrations. A number of experiments are still running, and will be sampled in coming years.
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Ma, Cha, Long Li, Gang Wang, and Xu Bo Yuan. "Synthesis and Characterization of Substituted-Ammonium Humic Acid Fluid Loss Additive for Oil-Based Drilling Fluids." Advanced Materials Research 1004-1005 (August 2014): 623–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.623.
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Using widely distributed and cheap lignite as starting material, humic acid was modified by octadecylamine, and a new kind of humic acid acetamide was prepared. The optimal reaction conditions of the humic acid acetamide polymer were obtained through laboratory tests as follow: the ratio of of humic acid and octadecylamine was 1:1.5, the reaction temperature was 150 °C, and the reaction time was 16~18 h. The new product was characterized by IR, and the results showed that this substituted-ammonium humic acid was successfully prepared by reacting parts of carboxyl group of humic acid with octadecylamine. HTHP filtration experiments demonstrated that the substituted-ammonium humic acid had good fluid loss properties. As a result, this substituted-ammonium humic acid polymer is an excellent fluid loss additive, and it could meet the requirement of drilling operation under extreme condition.
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MILLER, M. F., C. T. BOWMAN, and M. G. MUNGAL. "An experimental investigation of the effects of compressibility on a turbulent reacting mixing layer." Journal of Fluid Mechanics 356 (February 10, 1998): 25–64. http://dx.doi.org/10.1017/s002211209700791x.
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Experiments were conducted to investigate the effect of compressibility on turbulent reacting mixing layers with moderate heat release. Side- and plan-view visualizations of the reacting mixing layers, which were formed between a high-speed high-temperature vitiated-air stream and a low-speed ambient-temperature hydrogen stream, were obtained using a combined OH/acetone planar laser-induced fluorescence imaging technique. The instantaneous images of OH provide two-dimensional maps of the regions of combustion, and similar images of acetone, which was seeded into the fuel stream, provide maps of the regions of unburned fuel. Two low-compressibility (Mc=0.32, 0.35) reacting mixing layers with differing density ratios and one high-compressibility (Mc=0.70) reacting mixing layer were studied. Higher average acetone signals were measured in the compressible mixing layer than in its low-compressibility counterpart (i.e. same density ratio), indicating a lower entrainment ratio. Additionally, the compressible mixing layer had slightly wider regions of OH and 50% higher OH signals, which was an unexpected result since lowering the entrainment ratio had the opposite effect at low compressibilities. The large-scale structural changes induced by compressibility are believed to be primarily responsible for the difference in the behaviour of the high- and low-compressibility reacting mixing layers. It is proposed that the coexistence of broad regions of OH and high acetone signals is a manifestation of a more biased distribution of mixture compositions in the compressible mixing layer. Other mechanisms through which compressibility can affect the combustion are discussed.
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Dagys, Laurynas, Barbara Ripka, Markus Leutzsch, Gamal A. I. Moustafa, James Eills, Johannes F. P. Colell, and Malcolm H. Levitt. "<i>Geminal</i> parahydrogen-induced polarization: accumulating long-lived singlet order on methylene proton pairs." Magnetic Resonance 1, no. 2 (August 7, 2020): 175–86. http://dx.doi.org/10.5194/mr-1-175-2020.
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Abstract. In the majority of hydrogenative parahydrogen-induced polarization (PHIP) experiments, the hydrogen molecule undergoes pairwise cis addition to an unsaturated precursor to occupy vicinal positions on the product molecule. However, some ruthenium-based hydrogenation catalysts induce geminal hydrogenation, leading to a reaction product in which the two hydrogen atoms are transferred to the same carbon centre, forming a methylene (CH2) group. The singlet order of parahydrogen is substantially retained over the geminal hydrogenation reaction, giving rise to a singlet-hyperpolarized CH2 group. Although the T1 relaxation times of the methylene protons are often short, the singlet order has a long lifetime, provided that singlet–triplet mixing is suppressed, either by chemical equivalence of the protons or by applying a resonant radiofrequency field. The long lifetime of the singlet order enables the accumulation of hyperpolarization during the slow hydrogenation reaction. We introduce a kinetic model for the behaviour of the observed hyperpolarized signals, including both the chemical kinetics and the spin dynamics of the reacting molecules. Our work demonstrates the feasibility of producing singlet-hyperpolarized methylene moieties by parahydrogen-induced polarization. This potentially extends the range of molecular agents which may be generated in a hyperpolarized state by chemical reactions of parahydrogen.