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Academic literature on the topic 'MEA'

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Published: 4 June 2021
Last updated: 18 May 2024

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Journal articles on the topic "MEA"

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Dong, Weiliang, Qiongzhen Chen, Ying Hou, Shuhuan Li, Kai Zhuang, Fei Huang, Jie Zhou, et al. "Metabolic Pathway Involved in 2-Methyl-6-Ethylaniline Degradation by Sphingobium sp. Strain MEA3-1 and Cloning of the Novel Flavin-Dependent Monooxygenase SystemmeaBA." Applied and Environmental Microbiology 81, no. 24 (September 18, 2015): 8254–64. http://dx.doi.org/10.1128/aem.01883-15.

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ABSTRACT2-Methyl-6-ethylaniline (MEA) is the main microbial degradation intermediate of the chloroacetanilide herbicides acetochlor and metolachlor.Sphingobiumsp. strain MEA3-1 can utilize MEA and various alkyl-substituted aniline and phenol compounds as sole carbon and energy sources for growth. We isolated the mutant strain MEA3-1Mut, which converts MEA only to 2-methyl-6-ethyl-hydroquinone (MEHQ) and 2-methyl-6-ethyl-benzoquinone (MEBQ). MEA may be oxidized by the P450 monooxygenase system to 4-hydroxy-2-methyl-6-ethylaniline (4-OH-MEA), which can be hydrolytically spontaneously deaminated to MEBQ or MEHQ. The MEA microbial metabolic pathway was reconstituted based on the substrate spectra and identification of the intermediate metabolites in both the wild-type and mutant strains. Plasmidome sequencing indicated that both strains harbored 7 plasmids with sizes ranging from 6,108 bp to 287,745 bp. Among the 7 plasmids, 6 were identical, and pMEA02′ in strain MEA3-1Mut lost a 37,000-bp fragment compared to pMEA02 in strain MEA3-1. Two-dimensional electrophoresis (2-DE) and protein mass fingerprinting (PMF) showed that MEA3-1Mut lost the two-component flavin-dependent monooxygenase (TC-FDM) MeaBA, which was encoded by a gene in the lost fragment of pMEA02. MeaA shared 22% to 25% amino acid sequence identity with oxygenase components of some TC-FDMs, whereas MeaB showed no sequence identity with the reductase components of those TC-FDMs. Complementation withmeaBAin MEA3-1Mut and heterologous expression inPseudomonas putidastrain KT2440 resulted in the production of an active MEHQ monooxygenase.
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Dalgarno, Scott. "Mea Culpa Mea." Antioch Review 64, no. 3 (2006): 517. http://dx.doi.org/10.2307/4615022.

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Chen, Hong Wei, Long Chen, Wei Sun, Xin Liang Suo, and Jiang Tao Chen. "Research of the Activation of Methyldiethanolamine Absorbing Carbon Dioxide by Monoethanolamine." Advanced Materials Research 616-618 (December 2012): 1190–94. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.1190.

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The absorption of carbon dioxide into aqueous blends of MEA and MDEA is studied in a stirred-cell reactor. The absorption characteristics of MEA and MDEA are compared and the impact of different ratios of MEA to MDEA, MEA and MDEA concentrations on absorption rates and absorption efficiency are researched. The results indicate that small addition of MEA into MDEA could increase greatly absorption rates and efficiency and strengthen mass transfer; and under the condition of fixed MEA concentration, the larger the MDEA concentration, the better the activation effect.
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Karunarathne, Sumudu S., Dag A. Eimer, Klaus J. Jens, and Lars E. Øi. "Density, Viscosity, and Excess Properties of Ternary Aqueous Mixtures of MDEA + MEA, DMEA + MEA, and DEEA + MEA." Fluids 5, no. 1 (February 19, 2020): 27. http://dx.doi.org/10.3390/fluids5010027.

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This study presents the measured densities and viscosities of three ternary aqueous mixtures of tertiary and primary amines. The tertiary amines of n-methyldiethanolamine (MDEA), dimethylethanolamine (DMEA), diethylethanolamine (DEEA), and the primary amine monoethanolamine (MEA) at different concentrations (mass%) were mixed to prepare the liquid mixtures. The excess molar volume VE of the mixtures was analyzed using measured densities to acquire a better understanding of the molecular packing and intermolecular interactions in the mixtures. The excess free energy of activation ∆GE* and excess entropy of activation ∆SE* for viscous flow were determined from the measured viscosities by implementing the theory of rate processes of Eyring. Correlations based on the Redlich–Kister type polynomial were adopted to correlate the excess properties VE and ∆GE* as a function of the amine mole fraction and temperature. The results showed that the correlations were able to represent the measured data with satisfactory accuracies for engineering calculations.
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Fosbøl, Philip Loldrup, Mikkel Gielsager Pedersen, and Kaj Thomsen. "Freezing Point Depressions of Aqueous MEA, MDEA, and MEA−MDEA Measured with a New Apparatus." Journal of Chemical & Engineering Data 56, no. 4 (April 14, 2011): 995–1000. http://dx.doi.org/10.1021/je100994v.

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Vrachnos, Athanassios, Georgios Kontogeorgis, and Epaminondas Voutsas. "Thermodynamic Modeling of Acidic Gas Solubility in Aqueous Solutions of MEA, MDEA and MEA−MDEA Blends." Industrial & Engineering Chemistry Research 45, no. 14 (July 2006): 5148–54. http://dx.doi.org/10.1021/ie0600792.

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Azhgan, M., M. Farsi, and R. Eslamloueyan. "Solubility of CO2 in aqueous solutions of DAMP+MDEA, DAMP+MEA, DAH+MDEA and DAH+MEA." Journal of Natural Gas Science and Engineering 46 (October 2017): 526–32. http://dx.doi.org/10.1016/j.jngse.2017.08.014.

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Moloney, Elizabeth M. "Mea Culpa-Mea Maxima Culpa." Perspectives in Psychiatric Care 21, no. 4 (January 16, 2009): 155. http://dx.doi.org/10.1111/j.1744-6163.1983.tb00192.x.

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Mole. "Mea culpa, mea powerful culpa." Journal of Cell Science 131, no. 5 (March 1, 2018): jcs215707. http://dx.doi.org/10.1242/jcs.215707.

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Jin, Mei, Li Yan Zhou, Ping Lu, and Guo Xian Yu. "Absorption of CO2 from Flue Gas Using Mixed Amine Solution." Advanced Materials Research 781-784 (September 2013): 2201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2201.

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The MDEA-PZ binary system and the MDEA-PZ-MEA/DEA/ETA/TETA ternary system were used to absorb CO2 from the simulated flue gas. The experimental results showed that the best performance of the absorption of CO2was achieved under the mass ratio of MDEA to PZ of 10/4 in the MDEA-PZ binary system. In the MDEA-PZ-MEA/DEA/ETA/TETA ternary system, due to the different molecular structure of the additives, the absorption performance of CO2 was determined as follows: MDEA-PZ-TETA>MDEA-PZ-ETA>MDEA-PZ-MEA>MDEA-PZ-DEA. In the MDEA- PZ- TETA ternary system, the better absorption performance could be reached at the volume ratio of MDEA-PZ to TETA of 1:2. Moreover, it was indicated that there was a weakly negative interaction among MDEA, PZ and TETA.
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Dissertations / Theses on the topic "MEA"

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Gojela, Ntombekaya. "Hydrogen economy : MEA manufacturing for PEM electrolysers." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1483.

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The electrolysis of water was evaluated as a potentially efficient, as a low cost means of hydrogen production. The theoretical energy, voltage, current, and energy efficiencies of water electrolysis were considered by using various catalyst materials used in the fabrication of membrane electrode assemblies used in low temperature water electrolysis systems. Traditionally, iridium based catalysts have shown to be the most suitable material for its use on electrocatalysis of water to form hydrogen. This study showed that a combination of various elements as a binary and or ternary mixture in the base catalyst that was applied to the anode and cathode by using the Adam’s method had shown to give comparatively good results to that of using iridium oxide on its own. These catalysts were characterized by cyclic voltammetry, at different temperatures (30oC-80oC) with a range of catalyst loading of 0.2-0.5 mg.cm-2 noble metals. The study showed that the Ir40Co40 mixture as an anode catalyst was found to show highest hydrogen efficiency of 73 percent with a relatively low over potential of 0.925V at higher temperature of 80oC. The mixture also showed to give the best electrocatalytic activity with a low Tafel slope of 30.1mV.dec-1. Whereas the Ir50Pt50 showed a comparatively lower hydrogen efficiency of 65 percent with a lower over potential of 0.6V at 50oC. Ternary mixed oxide of Ir20Ru40Co40 showed an even lower over potential of 0.5- 0.6V over a large range of temperatures with a low hydrogen efficiency of 44 percent but gave good electrocatalytic activity in terms of the Tafel slope analysis. On the other hand, mixtures with relatively cheaper material such as Nickel in binary mixture systems such as Pt50Ni50 as cathode catalyst was found to show promising performance of a relatively low over potential that was less than 1.4 V with a low hydrogen efficiency of 62.1 percent Ternary cathode catalyst materials such as Pt33Ni33Co33 exhibited good performance with higher hydrogen efficiency of 65.2 percent at lower over potential of 1.2 V and a higher Tafel slope of 133.9 mV.dec-1 at 80 0C.
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Chladil, Ladislav. "Optimalizace MEA struktury pro nízkoteplotní palivové články." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218680.

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This master’s thesis focuses on optimization of electrode configuration in combination with a polymer membrane (MEA - Membrane Electrode Assembly) in terms of material and technology. The main goal was to create a functional measurement of MEA structures with three different types of carbon materials. The theoretical part focuses on the physical and chemical properties of low-temperature fuel cells with polymer membrane. The experimental section describes the manufacture of catalytic materials with different types of carbon and various contents platinum. Produced by electrode materials were investigated by cyclic voltammetry. The next step was to manufacture MEA structures and characteristics of VA measurement using a digitally controlled load in the experimental fuel cell Quintech.
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Tse, Laam Angela. "Membrane Electrode Assembly (MEA) Design for Power Density Enhancement of Direct Methanol Fuel Cells (DMFCs)." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11522.

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Micro-direct methanol fuel cells (micro-DMFC) can be the power supply solution for the next generation of handheld devices. The applications of the micro-DMFCs require them to have high compactness, high performance, light weight, and long life. The major goal of this research project is to enhance the volumetric power density of direct methanol fuel cells (DMFCs). A performance roadmap has been formulated and showed that patterning the planar membrane electrode assembly (MEA) to 2-D and 3-D corrugated manifolds can greatly increase the power generation with very modest overall volume increases. In this project, different manufacturing processes for patterning MEAs with corrugations have been investigated. A folding process was selected to form 2D triangular corrugations on MEAs for experimental validations of the performance prediction. The experimental results show that the volumetric power densities of the corrugated MEAs have improved by about 25% compared to the planar MEAs, which is lower than the expected performance enhancement. ABAQUS software was used to simulate the manufacturing process and identify the causes of deformations during manufacture. Experimental analysis methods like impedance analysis and 4 point-probes were used to quantify the performance loss and microstructure alteration during the forming process. A model was proposed to relate the expected performance of corrugated MEAs to manufacturing process variables. Finally, different stacking configurations and issues related to cell stacking for corrugated MEAs are also investigated.
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Andréa, Vinicius. "Estudos de durabilidade de conjuntos eletrodo-membrana-eletrodo (MEAs) produzidos por impressão à tela para uso em células a combustível do tipo PEM." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-08082013-152754/.

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Custo e durabilidade ainda são os maiores impeditivos para a entrada das células a combustível no mercado de dispositivos usados para produção de eletricidade. Assim, o objetivo deste trabalho foi avaliar a durabilidade dos conjuntos eletrodo-membrana-eletrodo (MEAs) produzidos no IPEN pelo método de impressão à tela para uso em células a combustível do tipo PEM. Para tanto, foi necessário desenvolver um protocolo adequado de teste de durabilidade de longa duração, visando obter estimativas da taxa de queda do potencial elétrico da célula a combustível ao longo do tempo e, assim, fazer inferência a respeito do tempo de vida deste dispositivo. Os MEAs testados durante este estudo foram preparados pelo método de impressão à tela com catalisador de Pt/C comercial e membrana Nafion® 115. O aprimoramento do protocolo de teste de durabilidade de longa duração se deu pela escolha dos procedimentos a serem executados e pelo ajuste de alguns parâmetros de operação da célula a combustível, tais como temperatura da célula, fluxo de H2 e fluxo de O2. Para a análise dos dados obtidos com os testes, foram aplicados métodos estatísticos de ajuste de modelos e curvas de polarização. Além disso, amostras da camada catalítica de um dos MEAs utilizados nos testes de durabilidade de longa duração foram analisadas por meio de microscopia eletrônica de transmissão (MET) para serem comparadas com amostras da camada catalítica de um MEA de controle. Para se avaliar o desempenho global da célula a combustível do tipo PEM em operações de longa duração, um dos grandes desafios foi fazer a separação entre as componentes de perda de desempenho que são reversíveis das irreversíveis. As estimativas obtidas para a taxa de queda do potencial elétrico da célula a combustível ao longo do tempo variaram num intervalo de 108,19 a 318,15 μV.h-1. Estes resultados podem ser considerados satisfatórios quando comparados com valores apresentados na literatura. Finalmente, as imagens obtidas por MET mostraram uma tendência de aumento no tamanho médio das partículas Pt em decorrência do tempo de operação dos MEAs, mas que não implicou numa queda significativa do desempenho das células a combustível do tipo PEM testadas.
Cost and durability still represent the major barriers to the entry of proton exchange membrane fuel cells (PEMFCs) in the market. Thus, the objective of this work was to assess the durability of membrane-electrode assemblies (MEAs) produced at IPEN through the sieve printing method to be used in PEMFCs. For this purpose, an adequate long-term test protocol was developed aiming to obtain estimates of the voltage decay rate and lifetime of the PEMFCs. In the preparation of the MEAs through the sieve printing method commercial Pt/C catalyst and Nafion® 115 membranes were used. In the development of the long-term test protocol some procedures were defined and the fuel cell operational parameters were adjusted, such as cell temperature, H2 and O2 flows. In the analysis of the data obtained from the tests, statistical methods and polarization curves were applied. Samples of the catalyst layer from a MEA used in a long-term test were compared with samples from a control MEA using a Transmission Electron Microscopy (TEM). To evaluate the overall performance of the PEMFCs in long-term operations, a major challenge was to make the separation between the components of performance loss that are reversible from the ones that are irreversible. The estimates for the voltage decay rate ranged from 110 to 318 μV.h-1. These results can be taken as satisfactory when compared with values reported in the literature. Finally, there was an increase in the average size of Pt particles in the catalyst of the long-term tested MEA, as observed in the micrographs. However, this increase did not lead to a significant performance loss of the PEMFCs.
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Corradini, Daniele. "Statistical characterization of cultured neural networks activity recorded via MEA." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20380/.

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In questa tesi si sono analizzate le attività di neuroni in coltura accoppiati con un Multi-Electrode Array (MEA) a 60 canali. Le reti neurali in vitro sono influenzate da diversi fattori, come la densità di coltura, l'età e l'animale di provenienza dei neuroni. Lo scopo di questa tesi è quello di caratterizzare questa variabilità attraverso varie analisi statistiche. Utilizzando un software sviluppato in Python si sono estratte 40 misure per descrivere un ampio spettro delle attività delle cellule, come lo spiking e i network bursts. Sono state caratterizzate le distribuzioni statistiche di queste feature, ed una analisi PCA per vedere la segregazione dei dati nelle classi considerate. Sono poi state implementate una analisi con K-Means Clustering e una classificazione mediante Random Forest, per caratterizzare la separazione spontanea e mediante label dei vari tipi di misurazioni. É stato studiato anche l'effetto del sottocampionamento temporale sulle misure, determinando che anche con un quarto della serie temporale disponibile si sono potute estrarre misure significative. Un altro tipo di sottocampionamento preso in considerazione è stato quello spaziale. Anche qui le misure si sono dimostrate robuste riducendo il numero di elettrodi da cui estrarre il segnale, fino ad un minimo di 10 elettrodi. Questa analisi della robustezza alla variabilità e al sottocampionamento delle misure di attività spontanea di reti di neuroni in vitro mediante setup MEA é utile per studiare gli effetti di sostanze chimiche, stimoli elettrici o malattie sulle colture nervose.
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Rafagnim, Nadine Zandoná 1992, Marcela Kotsuka da Silva Câmara 1981 Bastos, Henry França 1963 Meier, and Universidade Regional de Blumenau Programa de Pós-Graduação em Engenharia Química. "Análise numérica de escoamento reativo CO2-MEA em prato perfurado." reponame:Biblioteca Digital de Teses e Dissertações FURB, 2018. http://www.bc.furb.br/docs/DS/2018/364042_1_1.pdf.

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Orientador: Marcela Kotsuka da Silva Câmara Bastos.
Coorientador: Henry França Meier.
Dissertação (Mestrado em Engenharia Química) - Programa de Pós-Graduação em Engenharia Química, Centro de Ciências Tecnológicas, Universidade Regional de Blumenau, Blumenau.
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DE, CEGLIA ROBERTA. "Unraveling the role of cns acidosis in experimental autoimmune encephalomyelitis." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/46925.

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Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the Central Nervous System (CNS) featuring severe neuronal degenerative processes. Emerging findings indicate that several injurious molecular and cellular cascades are contributing to neurodegeneration. Among them, CNS acidosis has been recently demonstrated to have a detrimental role in Experimental Autoimmune Encephalomyelitis (EAE). Good candidates to trigger acidosis-mediated neurodegeneration are represented by Acid Sensing Ion Channels (ASICs) which are H+-gated cation channels of the CNS. We measured CNS acidosis in EAE mice by a non-invasive magnetic resonance spectroscopy (MRS), establishing the presence of a substantial extracellular acidification in the Cerebellum (CB). We next examined the ability of Diminazene Aceturate (DA), a new specific ASICs inhibitor, to promote neuroprotective effects in chronic EAE mice. Behavioral and histological evaluations indicated that DA significantly improved walking performances in EAE mice, ameliorated their neurological deficits, as well as, reduced myelin and axonal loss in both CB and Spinal Cord. Additionally, we model in vitro the harmful electrophysiological alterations elicited by acidosis using primary neuronal cultures coupled with Micro Electrode Array (MEA) devices. While an acute acidic treatment caused a rapid and transient reduction of firing activity, long term acidosis caused the chronic impairment of synchronized neuronal electrophysiological activity, and a significant loss of pre-synaptic boutons. DA efficiently compensated the loss of firing activity derived from acute acidosis, as well as protected neurons from injurious effects elicited by chronic acidosis. In conclusion our data suggest that ASICs activation is involved in mediating neuronal derangement during acute neuroinflammation and that the early intervention with specific ASICs antagonists may attenuate these detrimental effects.
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Hajiaghayi, Monir. "Empirical analysis of the MEA and MFE RNA secondary structure prediction." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/29473.

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RNA molecules play critical roles in the cells of organisms, including roles in gene regulation, catalysis, and synthesis of proteins. Since their functions largely depend on their folded structures, having accurate and efficient methods for RNA structure prediction is increasingly valuable. A number of computational approaches have been developed to predict RNA secondary structure. There have been some recent advances for two of these approaches, namely Minimum Free Energy (MFE) and Maximum Expected Accuracy (MEA). The main goals of this thesis are twofold: 1) to empirically analyze the accuracy (i.e., the number of correctly predicted base pairs) of the MFE and MEA algorithms in different energy models and 2) to estimate the free energy parameters specifically for the MEA by using the constraint generation (CG) approach. We present new results on the degree to which different factors influence the prediction accuracy MFE and MEA. The factors that we consider are: structural information that is provided in addition to RNA sequence, thermodynamic parameters, and data set size. Structural information significantly increases the accuracy of these methods. The relative performance of MFE and MEA changes according to the free energy parameters used; however, both have the best performance when they use Andronescu et al.'s BL* parameter set. Having bigger data sets results in less variation in prediction accuracy of the MFE and MEA algorithms. Furthermore, we try to find better free energy parameters for the MEA algorithm. For our purpose, we adapt the CG approach so that it specifically optimizes parameters for MEA. Overall, when parameters are trained using MFE, they slightly outperform the parameters estimated for MEA. For the MEA algorithm, we also study the effect of parameter γ which controls the relative sensitivity and positive predictive value (PPV). We obtain that when γ=1, the accuracy of MEA (in terms of F-measure on the BL* parameter set) is better than its accuracy for other values of γ. We also find that the sensitivity and PPV of MEA will interestingly change for different values of γ using the BL* parameter set.
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Giroux, Amy. "Mea Familia: Ethnic Burial Identifiers in St. Michael's Cemetery, Pensacola, Florida." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2151.

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Grave markers from St. Michael'ss Cemetery in Pensacola, Florida, were studied for evidence of ethnicity and acculturation. The 1,447 grave markers dating from 1870 to 1939 were used to test two hypotheses: 1) the grave markers for ethnic groups represented in the cemetery during the project's time period have identifiable sets of burial attributes; and 2) changes in the visible ethnic attribute sets show evidence of the acculturation of ethnic groups over time. Physical attributes pertaining to grave markers, and personal characteristics (e.g. sex, age) for the individuals inscribed upon the markers were collected for analysis. Historical sources were used to assign ethnicity to each marker by determining the ancestry of the individuals memorialized. Grave marker attributes for ten ethnic groups were examined. The statistical results indicate a correlation of ethnicity with marker attributes. Central Europeans had the most identifiable preferences including large markers, vertical markers, floral design motifs, and headstone molding. Other observable ethnic patterns include the use of family markers, non-marble materials, horizontal markers, relationship wording, and religious symbolism. Spatial analysis illustrates that ethnic markers were dispersed across the cemetery; this lack of segregation in the graveyard may be due to acculturation. However, the diachronic changes in burial identifiers cannot be clearly ascribed to the acculturation of immigrants. Use of marble materials and the height of markers diminished for all ethnic groups. Changes in the memorialization industry were likely contributing factors to differences in attribute selection over time. Therefore, while ethnic burial identifiers are statistically visible in the cemetery landscape, attribute changes are not exclusively caused by acculturation.
M.A.
Department of Anthropology
Sciences
Anthropology MA
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Du, Preez Louis Jacobus. "The reactive absorption of CO2 into solutions of MEA/2-propanol." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4192.

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Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The discovery that the reaction of CO2 with primary amines in both aqueous and non-aqueous media provides a viable chemical method for determining the effective interfacial mass transfer area for separation column internals has lead to an increase in the interest of studying the reaction kinetics and determining the governing reaction rate expressions. For the absorption studies conducted on these systems, many authors assumed that power rate law reaction kinetics govern the reaction rate, which simplified the derivation of absorption correlations. This has already been proven to be an over simplifying assumption, since many authors suggest a non-elementary rate expression based on the pseudo-steady state hypothesis for the reactive zwitterion intermediate to be valid. An evaluation of the existing reaction rate expressions for the homogeneous liquid phase reaction of CO2 and mono-ethanolamine (MEA) in a 2-propanol solvent system was performed. The reaction rate profiles of CO2 and MEA at 25ºC, 30ºC and 35ºC, and relative initial concentrations of [MEA]i = [CO2]i, [MEA]i = 2.5[CO2]i, [MEA]i = 4[CO2]i were determined by means of an isothermal CSTR set-up. Scavenging of the unreacted MEA with benzoyl chloride provided the means to be able to stop the reaction in the product stream. This in turn allowed for the construction of concentration- and reaction rate profiles. The reaction rate data was modelled on various rate expressions by means of a MATLAB® non-linear estimation technique, employing the Levenberg-Marquard algorithm for minimizing the loss function. It was concluded that the rate expressions proposed in literature are insufficient and a rate expression derived fundamentally from first principals is proposed: [ ][ ] [ ] [ ][ ] [ ]2 MEA 1 2 2 -r = k CO RNH - k2 Z + k3 Z RNH2 - k4 S where ki are the reaction rate constants, Z is the zwitterion reactive intermediate and S the salt product of the overall reaction mechanism. In order to be able to determine the effective interfacial mass transfer area, the absorption rate per unit area or specific rate of absorption for the solute gas as a rate expression function of species concentration must firstly be determined. This is achieved by performing experimental absorption runs on a gas-liquid contactor of known surface area. This study incorporated the well known wetted wall experimental set-up. The aim was to construct and implement a wetted wall set-up and conduct absorption experiments for a gas side CO2 concentration range stretching from pure CO2 to diluted gas mixtures absorbing into solutions of varying MEA concentrations. Validation of the set-up was done by performing experiments at similar conditions to a previous study. The study then proceeded to determine the absolute and specific absorption rates at CO2 mass percentages of 100%, 78%, 55% and 30% into solutions of MEA concentrations of 0.25 and 0.3 mol/L. These runs were conducted at 25ºC and 30ºC. The wetted wall was designed to facilitate absorption studies at column heights of 60, 90 and 105mm. This allowed the investigation of the effect that surface area and column height has on the absolute rate of absorption as well as the CO2 and MEA concentrations in the liquid phase It was found that the specific absorption rate is independent of contact time, which is consistent with the rapid nature of the reaction. It was furthermore found that an increase in MEA concentration caused an increase in the absorption rate. The effect of temperature is linked with the solubility of CO2 in the solution. As the temperature increases, the solubility of CO2 decreases, but the absorption rate increases. The result is that it seems as if a change in temperature has no effect on the absorption rate, when in actual fact it does. An increase in the amount of CO2 absorbed is noticed for an increase in wetted wall surface area. This is expected and indicates that there is an increase in the amount of CO2 absorbed as the column length increases. Stopping the absorption reaction by means of MEA scavenging with benzoyl chloride at various column heights will allow for the construction of a concentration profile for both CO2 and MEA as a function of column height. These profiles will allow for the derivation of a non-elementary rate expression governing the specific absorption rate. This has been identified as ‘n area of great interest for future investigation.
AFRIKAANSE OPSOMMING: ‘n Groot navorsingsbelangstelling in die reaksiekinetika van CO2 en monoethanolamien (MEA) het ontstaan sedert die ontdekking dat hierdie reaktiewe sisteem ook ‘n goeie metode is vir die bepaling van die effektiewe massaoordragsoppervlakte van gestruktureerde pakkingsmateriaal. Die klem val op die bepaling van eerstens die mees geskikte en akkurate model om die reaksiekinetika te beskryf wat dan gebruik kan word om die absorbsiekinetika deeglik te karaktariseer. Sommige van die vorige navorsers het vereenvoudigende aannames gemaak rakende die reaksiekinetika ten einde die bepaling van geskikte absopsievergelykings te vergemaklik. Ander het gevind dat die nie-elementêre, pseudo-gestadigde toestand hipotese gebasseer op die reaktiewe zwitterioon tussenproduk van die reaksie ‘n meer verteenwoordigende kinetiese model is. Hierdie studie is eerstens gemik op die evaluasie van die bestaande reaksiekinetikavergelykings deur die homogene vloeistoffase reaksie van CO2 met mono-etanolamien (MEA) in die oplosmiddel, 2-propanol te ondersoek. Die studie is uitgevoer in ‘n isoterme CSTR sisteem by onderskeidelik 25ºC, 30ºC en 35ºC en MEA konsentrasies van [MEA]i = [CO2]i, [MEA]i = 2.5[CO2]i en [MEA]i = 4[CO2]i. Die voorgestelde reaksiekinetikavergelykings was gemodelleer met ‘n nie-lineêre datapassingstegniek verskaf deur die sagtewarepakket, MATLAB® wat die Levenberg- Marquard algoritme gebruik om die resfunksie te minimeer. Uit die teorie en datapassing word die volgende vergelyking voorgestel: [ ][ ] [ ] [ ][ ] [ ]2 MEA 1 2 2 -r = k CO RNH - k2 Z + k3 Z RNH2 - k4 S waar ki die reaksietempokonstante voorstel, Z die zwitterioontussenproduk en S die soutproduk. Die eerste stap in die bepaling van die effektiewe massaoordragsarea van gestruktureerde pakkingsmateriaal is om ‘n geskikte vergelyking of korrelasie vir die spesifieke absorpsie van die gas te bepaal. Dit word gedoen deur absoprsie eksperimente te doen op toerusting van bekende oppervlakarea. Hierdie studie het die reeds bekende ‘wetted wall’ opstelling gebruik. Die hoof doelwit van hierdie absorpsiestudie was om ‘n werkende opstelling te bou en absorpsie eksperimente vir CO2 konsentrasies wat strek van suiwer CO2 tot verdunde mengsels uit te voer. Die konsentrasie MEA is ook gevarieër. Die geskiktheid van die opstelling is eerstens getoets deur eksperimentele lopies uit te voer by soorgelyke toestande as ‘n vorige studie. Die doel van die studie is om die absolute en spesifieke absorpsietempos van CO2 by gasfase massapersentasies van 100%, 78%, 55% en 30% in MEA/2-propanol oplossings met MEA konsentrasies van 0.25 en 0.3 mol/L te bepaal. Die lopies is uigevoer by beide 25ºC en 30ºC. Die opstelling is ook ontwerp om absorpsie eksperimente by verskillende kolomhoogtes uit te voer. Hierdie hoogtes is 60, 90 en 105mm. Hierdie studie het tweedens gefokus op die effek wat absorpsiearea en kolomhoogte op die absorpsietempo van CO2 het. Die resultate van die studie toon dat die absorpsietempo onafhanklik is van kontaktyd. Dit stem saam met die vinnige reaksietempo. ‘n Toename in MEA konsentrasie het ‘n toename in spesifieke absorpsietempo tot gevolg, terwyl die effek van temperatuur gekoppel kan word aan die oplosbaarheid van CO2. Soos die temperatuur toeneem, neem die absolute absorpsietempo toe, maar die oplosbaarheid van CO2 neem af, dit het beide ‘n toenemende en afnemende effek op die spesifieke absorpsietempo. Die hoeveelheid CO2 geabsorbeer neem toe met ‘n toename in kolomhoogte. Die konsentrasie MEA in die uitlaatvloeistof toon ‘n skynbare eksponensiële afname met ‘n toename in kolomhoogte. ‘n Studie gemik om die konsentrasieprofiele van CO2 en MEA as ‘n funksie van kolomhoogte te bepaal, word voorgestel. Absorpsiemodelle en korrelasies kan dan afgelei word uit hierdie profiele, wat die berekening van die effektiewe massaoordragsarea akkuraat sal maak. Dit sal deel vorm van toekomstige navorsing.
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Books on the topic "MEA"

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Mea. Amsterdam: Atlas, 2009.

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Ștefan, Toader I. Viața mea. București: Editura Albatros, 1989.

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Mea culpa. Warszawa]: Axis Mundi, 2010.

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translator, Beck Art, ed. Mea Roma. Bristol: Shearsman Books, 2018.

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Kenneth, Hall, ed. Mea Cuba. New York: Farrar, Straus, Giroux, 1994.

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Mahon, Eduardo. Mea culpa. Cuiabá, MT: Carlini & Caniato Editorial, 2020.

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Ursu, A. F., writer of preface and Bosomitu, Ștefan, 1982- writer of postface, eds. Europa mea. Iași: Polirom, 2021.

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Mea culpa. Montréal, Québec: Hurtubise, 2001.

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Infante, G. Cabrera. Mea Cuba. Barcelona: Plaza & Janés, 1992.

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Christi, Aura. Împotriva mea. București: Editura Du Style, 1995.

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Book chapters on the topic "MEA"

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Morgan, Michael M., MacDonald J. Christie, Thomas Steckler, Ben J. Harrison, Christos Pantelis, Christof Baltes, Thomas Mueggler, et al. "MEA." In Encyclopedia of Psychopharmacology, 751. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-68706-1_4345.

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Oette, Mark, Marvin J. Stone, Hendrik P. N. Scholl, Peter Charbel Issa, Monika Fleckenstein, Steffen Schmitz-Valckenberg, Frank G. Holz, et al. "MEA." In Encyclopedia of Molecular Mechanisms of Disease, 1271. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-29676-8_7086.

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Bährle-Rapp, Marina. "Undecylenamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 573. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_10866.

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Bährle-Rapp, Marina. "Cocamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 120. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_2226.

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Bährle-Rapp, Marina. "Tallowamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 543. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_10301.

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Bährle-Rapp, Marina. "Behenamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 61. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_1037.

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Bährle-Rapp, Marina. "Lactamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 308. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5746.

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Bährle-Rapp, Marina. "Lauramide MEA." In Springer Lexikon Kosmetik und Körperpflege, 312. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5837.

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Bährle-Rapp, Marina. "Linoleamide MEA." In Springer Lexikon Kosmetik und Körperpflege, 323. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_6029.

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Bährle-Rapp, Marina. "MEA-Benzoate." In Springer Lexikon Kosmetik und Körperpflege, 343. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_6361.

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Conference papers on the topic "MEA"

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Al Mahmud, Abdullah, Rick van de Ven, Laurens Slats, Esther van der Veen, Zlati Petkov, and Omar Mubin. "MEA." In CHI '14: CHI Conference on Human Factors in Computing Systems. New York, NY, USA: ACM, 2014. http://dx.doi.org/10.1145/2559206.2581228.

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Setameteekul, Anothai, Amornvadee Veawab, and Adisorn Aroonwilas. "Parametric Analysis of Mass-Transfer Performance in CO2 Absorber Using Aqueous MEA and MEA/MDEA." In 2006 IEEE EIC Climate Change Conference. IEEE, 2006. http://dx.doi.org/10.1109/eicccc.2006.277212.

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Orangi, Sina, Solomon Aforkoghene Aromada, Neda Razi, and Lars Erik Øi. "Simulation and Economic Analysis of MEA+PZ and MDEA+MEA Blends in Post-combustion CO2 Capture Plant." In The First SIMS EUROSIM Conference on Modelling and Simulation, SIMS EUROSIM 2021, and 62nd International Conference of Scandinavian Simulation Society, SIMS 2021, September 21-23, Virtual Conference, Finland. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp21185317.

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Boudiaf, Chems Eddine, Alejandro Calleja Bezares, Atef El Nakib, Luis Andrés Mariño, Jorge Martín de Valmaseda, and Ainhoa Muñiz Quintana. "Mars Exploratory Aircraft (MEA)." In 2023 Regional Student Conferences, Region I - North East. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2023. http://dx.doi.org/10.2514/6.2023-72614.

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Maneeintr, Kreangkrai. "Density and Viscosity Correlations of Solution Systems of MEA-Water, MDEA-Water and MEA-MDEA-Water for CO2 Removal Process." In Power and Energy Systems. Calgary,AB,Canada: ACTAPRESS, 2013. http://dx.doi.org/10.2316/p.2013.800-092.

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Fambrini, Francisco, Jose Hiroki Saito, and Luis Mariano Del Val Cura. "MEA recording system circuit implementation." In IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society. IEEE, 2017. http://dx.doi.org/10.1109/iecon.2017.8217495.

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Krewer, Ulrike, Junyoung Park, Jinhwa Lee, and Hyejung Cho. "Storage of DMFC MEA at Extreme Temperatures." In ASME 2008 6th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2008. http://dx.doi.org/10.1115/fuelcell2008-65018.

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This paper investigates the change in performance of DMFC membrane electrode assemblies (MEAs) after storage at −10°C and 60°C under different experimental conditions. It highlights the importance of methanol concentration, an MEA’s material properties such as membrane material and catalyst loading, as well as the reactivation procedure. Storage at 60°C and concentrations below 1M methanol had no negative effect on MEA performance while storage at 60°C in a 4 M methanol solution could cause a severe performance decrease. Application of a reverse current for 10 s to a MEA which was affected by such storage was found to reinstall original performance. The effect of storage at −10°C on MEA performance strongly depends on MEA properties. MEAs are grouped into three different categories with regard to suitability for low temperature storage: not affected, reversibly affected, and irreversibly affected. The reversibly affected MEAs could be instantly and completely reactivated by reverse current. MEA materials such as various hydrocarbon membranes and high catalyst loadings as well as the manufacturing methods CCM (catalyst coated on the membrane) and CCS (catalyst coated on the substrate) were found to be principally suitable to build MEAs tolerant to storage at −10° C.
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Gullotta, Justin, Lakshmi Krishnan, Dylan Share, Daniel Walczyk, and Raymond Puffer. "Adaptive Process Control and In-Situ Diagnostics for High Temperature PEM MEA Manufacturing." In ASME 2010 8th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2010. http://dx.doi.org/10.1115/fuelcell2010-33231.

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The most critical step in high temperature proton exchange membrane (PEM) MEA manufacturing is sealing of the membrane between the two electrodes. This sealing process is typically conducted using a precision hydraulic thermal press. In order to achieve cost-effective high-volume MEA manufacturing, it is important to reduce the variability in MEA performance due to variations in incoming material properties and dimensions, and to reduce the unit process cycle time. This paper explains the application of real time adaptive process controls (APC) combined with effective in-situ diagnostics during the MEA sealing process to achieve greater uniformity and performance of high temperature PEM MEAs. The in-situ impedance measurement is carried out in a precision thermal press using a milliohmmeter by reading the complex impedance of the MEA at 1 kHz as the components of the MEA are sealed. This signal is then used to adjust the pressing process parameters in real time to achieve more uniform MEA performance. An experiment was carried out in an attempt to identify the impedance parameter which correlated most closely with the MEA’s future performance. Using these impedance parameters during pressing, we are able to reliably produce MEAs using the real time APC technique that perform consistently in a single cell test fixture with more than a 50% reduction in pressing time.
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Gorokhov, Alexei. "Antenna selection algorithms for MEA transmission systems." In Proceedings of ICASSP '02. IEEE, 2002. http://dx.doi.org/10.1109/icassp.2002.5745244.

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Gorokhov. "Antenna selection algorithms for MEA transmission systems." In IEEE International Conference on Acoustics Speech and Signal Processing ICASSP-02. IEEE, 2002. http://dx.doi.org/10.1109/icassp.2002.1005282.

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Reports on the topic "MEA"

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Wang, Xiaojing. Update on MEA AST. Office of Scientific and Technical Information (OSTI), May 2023. http://dx.doi.org/10.2172/1972172.

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Wang, Xiaojing, Calita Quesada, Rangachary Mukundan, and Rodney Borup. Update on MEA AST: Discussion of modified AST. Office of Scientific and Technical Information (OSTI), April 2024. http://dx.doi.org/10.2172/2342027.

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Ohad, Nir, and Robert Fischer. Control of Fertilization-Independent Development by the FIE1 Gene. United States Department of Agriculture, August 2000. http://dx.doi.org/10.32747/2000.7575290.bard.

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A fundamental problem in biology is to understand how fertilization initiates reproductive development. During plant reproduction, one sperm cell fuses with the egg to form an embryo, whereas a second sperm cell fuses with the adjacent central cell nucleus to form the endosperm tissue that supports embryo and/or seedling development. To understand the mechanisms that initiate reproduction, we have isolated mutants of Arabidopsis that allow for replication of the central cell and subsequent endosperm development without fertilization. In this project we have cloned the MEA gene and showed that it encode a SET- domain polycomb protein. Such proteins are known to form chromatin-protein complexes that repress homeotic gene transcription and influence cell proliferation from Drosophylla to mammals. We propose a model whereby MEA and an additional polycomb protein we have cloned, FIE , function to suppress a critical aspect of early plant reproduction and endosperm development, until fertilization occurs. Using a molecular approach we were able to determine that FIE and MEA interact physically, suggesting that these proteins have been conserved also during the evolution of flowering plants. The analysis of MEA expression pattern revealed that it is an imprinted gene that displays parent-of- origin-dependent monoallelic expression specifically in the endosperm tissue. Silencing of the paternal MEA allele in the endosperm and the phenotype of mutant mea seeds support the parental conflict theory for the evolution of imprinting in plants and mammals. These results contribute new information on the initiation of endosperm development and provide a unique entry point to study asexual reproduction and apomixis which is expected to improve crop production.
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Zhu, Yimin. Engineered Nanostructured MEA Technology for Low Temperature Fuel Cells. Office of Scientific and Technical Information (OSTI), July 2009. http://dx.doi.org/10.2172/959141.

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Glick, Reuven, and Andrew Rose. Currency Unions and Trade: A Post-EMU Mea Culpa. Cambridge, MA: National Bureau of Economic Research, September 2015. http://dx.doi.org/10.3386/w21535.

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Mukundan, Rangachary, Chung Lee, Xiaojing Wang, Siddharth Komini Babu, Tanya Agarwal, Jacob Spendelow, and Rodney Borup. MEA Durability and AST Development. National Lab Principal Investigators. Office of Scientific and Technical Information (OSTI), March 2022. http://dx.doi.org/10.2172/1856116.

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Fletcher, James H., Joseph L. Campbell, Philip Cox, and William J. Harrington. New MEA Materials for Improved DMFC Performance, Durability and Cost. Office of Scientific and Technical Information (OSTI), September 2013. http://dx.doi.org/10.2172/1092952.

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Yandrasits, Michael A. Final Report - MEA and Stack Durability for PEM Fuel Cells. Office of Scientific and Technical Information (OSTI), February 2008. http://dx.doi.org/10.2172/923720.

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Schulze, M., N. Wagner, and G. Steinhilber. Characterization and basic research investigations at PEFC electrodes and MEA. Office of Scientific and Technical Information (OSTI), December 1996. http://dx.doi.org/10.2172/460318.

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Ohad, Nir, and Robert Fischer. Regulation of Fertilization-Independent Endosperm Development by Polycomb Proteins. United States Department of Agriculture, January 2004. http://dx.doi.org/10.32747/2004.7695869.bard.

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Arabidopsis mutants that we have isolated, encode for fertilization-independent endosperm (fie), fertilization-independent seed2 (fis2) and medea (mea) genes, act in the female gametophyte and allow endosperm to develop without fertilization when mutated. We cloned the FIE and MEA genes and showed that they encode WD and SET domain polycomb (Pc G) proteins, respectively. Homologous proteins of FIE and MEA in other organisms are known to regulate gene transcription by modulating chromatin structure. Based on our results, we proposed a model whereby both FIE and MEA interact to suppress transcription of regulatory genes. These genes are transcribed only at proper developmental stages, as in the central cell of the female gametophyte after fertilization, thus activating endosperm development. To test our model, the following questions were addressed: What is the Composition and Function of the Polycomb Complex? Molecular, biochemical, genetic and genomic approaches were offered to identify members of the complex, analyze their interactions, and understand their function. What is the Temporal and Spatial Pattern of Polycomb Proteins Accumulation? The use of transgenic plants expressing tagged FIE and MEA polypeptides as well as specific antibodies were proposed to localize the endogenous polycomb complex. How is Polycomb Protein Activity Controlled? To understand the molecular mechanism controlling the accumulation of FIE protein, transgenic plants as well as molecular approaches were proposed to determine whether FIE is regulated at the translational or posttranslational levels. The objectives of our research program have been accomplished and the results obtained exceeded our expectation. Our results reveal that fie and mea mutations cause parent-of-origin effects on seed development by distinct mechanisms (Publication 1). Moreover our data show that FIE has additional functions besides controlling the development of the female gametophyte. Using transgenic lines in which FIE was not expressed or the protein level was reduced during different developmental stages enabled us for the first time to explore FIE function during sporophyte development (Publication 2 and 3). Our results are consistent with the hypothesis that FIE, a single copy gene in the Arabidopsis genome, represses multiple developmental pathways (i.e., endosperm, embryogenesis, shot formation and flowering). Furthermore, we identified FIE target genes, including key transcription factors known to promote flowering (AG and LFY) as well as shoot and leaf formation (KNAT1) (Publication 2 and 3), thus demonstrating that in plants, as in mammals and insects, PcG proteins control expression of homeobox genes. Using the Yeast two hybrid system and pull-down assays we demonstrated that FIE protein interact with MEA via the N-terminal region (Publication 1). Moreover, CURLY LEAF protein, an additional member of the SET domain family interacts with FIE as well. The overlapping expression patterns of FIE, with ether MEA or CLF and their common mutant phenotypes, demonstrate the versatility of FIE function. FIE association with different SET domain polycomb proteins, results in differential regulation of gene expression throughout the plant life cycle (Publication 3). In vitro interaction assays we have recently performed demonstrated that FIE interacts with the cell cycle regulatory component Retinobalsoma protein (pRb) (Publication 4). These results illuminate the potential mechanism by which FIE may restrain embryo sac central cell division, at least partly, through interaction with, and suppression of pRb-regulated genes. The results of this program generated new information about the initiation of reproductive development and expanded our understanding of how PcG proteins regulate developmental programs along the plant life cycle. The tools and information obtained in this program will lead to novel strategies which will allow to mange crop plants and to increase crop production.
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