Dissertations / Theses on the topic 'MEA'
To see the other types of publications on this topic, follow the link: MEA.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'MEA.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Gojela, Ntombekaya. "Hydrogen economy : MEA manufacturing for PEM electrolysers." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1483.
Full textAbstract:
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.
2
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.
Full textAbstract:
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.
3
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.
Full textAbstract:
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.
4
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/.
Full textAbstract:
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.
5
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/.
Full textAbstract:
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.
6
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.
Full textAbstract:
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.
7
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.
Full textAbstract:
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.
8
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.
Full textAbstract:
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.
9
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.
Full textAbstract:
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
10
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.
Full textAbstract:
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.
11
Kumar, Ameet. "Critical points in the More Electric Aircraft (MEA) converter-machine chain." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23815/.
Full textAbstract:
This research aims to analyze the critical points of the inverter-to-machine chain used in the actuation system of MEA. To analyze the critical points, it is necessary to investigate the Partial Discharge Inception Voltage (PDIV) of the printed circuit board (PCB, representative models of the high voltage part terminal part of the inverter) by considering the effects of aerospace conditions like pressure, temperature, and humidity. Also, the endurance tests of twisted pairs (TPs, representative models of the turn/turn insulation) at aerospace conditions is investigated. This is necessary to assess the life of the machine when it is stressed by repetitive square wave/sinusoidal AC voltages. These experiments help to find the proper way to design and qualify MEA actuators.
In this research, the effect of AC voltages, space charges at DC, temperature, pressure, and converter waveforms have been analyzed on different PCB models. Results show that an increased temperature decreases the PDIV and a reduction of PDIV is observed also due to a reduction of pressure. It is also analyzed that space charges play an important role in the measurement of PDIV at DC. Finally, the effect of converter waveforms supplied by SiC is analyzed, where it is observed that there is an 8% increase of PDIV as compared to the PDIV in AC. After these entire tests, it is concluded that the HV terminal part is not critical in the sense of PD occurrence.
After the inverter part, the behavior of turn/turn insulation when it is continuously stressed by repetitive square wave/ AC 50 kHz voltages above PDIV has been analyzed. The results obtained from both the supplies are compared with each other to understand the effect of supply type and frequency on the endurance, finally, the effect of humidity on the endurance of the twisted pairs has been analyzed. It is observed after all these endurance tests that the corona-resistant wire cannot endure PD for a long time in aerospace conditions.
12
MADEDDU, CLAUDIO. "Modeling and Analysis of the CO2 Post-Combustion Process with MEA." Doctoral thesis, Università degli Studi di Cagliari, 2018. http://hdl.handle.net/11584/257330.
Full textAbstract:
Carbon dioxide capture by means of reactive absorption-stripping using MEA is a very extensively studied process and its modeling represents an open issue in the specialized literature.
In this thesis a rigorous rate-based model is developed in Aspen Plus environment. A new approach to the modeling based on the analysis of the system fluid dynamics is adopted. In this way, it is possibile to find the correct numerical solution of the system of equations derived from the material and energy balances. As part of the model development, the kinetic parameters of the reaction between CO2 and MEA are calibrated to minimize the standard error between the model results and the experimental data. The model is validated for both the absorber and the stripper considering several pilot-plant facilities with different sizes and operating conditions. Moreover, in the case of the stripper it is found that a correct model of the process leads to a significant improvement in the estimation of the reboiler duty. Subsequent to the model validation, the analysis of the design of an industrial scale plant is taken into account for different values of the lean solvent loading. In particular, a two-step procedure that consists in the evaluation of the minimum solvent flow rate with an infinite packing height and the subsequent evaluation of the effective solvent flow rate and packing height is used for the absorption column. Moreover, the operating conditions to avoid isothermal zones in the absorber are determined. When the stripper is considered, it is highlighted that the reboiler duty is needed to reverse the absorption reactions only. For this reason, an alternative plant configuration that reduces the energy consumption is adopted and a new criterion for the determination of the packing height is proposed for the stripping column. In the end, in order to obtain the minimum reboiler duty, it is found that the rich solvent, i.e., the stripper feed, must be sent at the highest possible temperature, which is limited by the minimum temperature approach in the cross heat-exchanger.
13
Cottance, Myline. "Contribution au développement d'interfaces neuro-électroniques." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1105/document.
Full textAbstract:
Les travaux menés au cours de cette thèse portent sur la microfabrication d'interfaces neuro-électroniques pour des applications en neurosciences. Nous avons choisi de nos focaliser sur la réhabilitation fonctionnelle motrice et sensorielle en développant différentes matrices de micro-électrodes (MEA) respectivement, des sondes neuronales rigides et des implants rétiniens souples. Selon les applications visées, deux types de substrats ont été utilisés pour concevoir ces MEA. Pour des analyses ou expériences in-vitro, les MEA (sondes neuronales) ont plutôt été réalisées sur des substrats rigides tels que le silicium ou le verre, tandis que pour les expériences in-vivo, les MEA (implants rétiniens) ont été réalisées sur des substrats souples tels que des polymères biocompatibles (polyimide ou parylène). Ces MEA ont été fabriquées avec différents matériaux d'électrodes (diamant dopé, platine, platine noir et or) qui ont également été testés afin de déterminer leur capacité en enregistrement et/ou stimulation. De plus, à l'aide de travaux de modélisation numérique, nous avons validé le concept d'une géométrie tridimensionnelle avec grille de masse permettant une stimulation plus focale des cellules. Cette thèse a ainsi contribué à stabiliser différents procédés de fabrication pour obtenir des MEA plus reproductibles ainsi que pour améliorer leur rendement. Elle a également permis d'établir un suivi et un protocole expérimental pour assurer une traçabilité des MEA et contrôler leur performances à toutes les étapes : depuis leur fabrication au moyen de techniques électrochimiques (CV, EIS) jusqu'aux expériences biologiques in-vitro et in-vivoThe work lead during this thesis deals with microfabrication of neuro-electronic interfaces for neuroscience applications. We have chosen to focus on motor and sensory function rehabilitations by developing Micro-Electrode Arrays (MEA) respectively, rigid neural probes and flexible retinal implants. According to the targeted applications, two types of substrates have been used to achieve these MEA. For analysis or in vitro experiments, neural probes MEA have been realized on rigid substrates such as silicon or glass whereas for in-vivo experiments, retinal implants MEA have been realized on flexible substrates such as biocompatible polymers (polyimide or parylene). These MEA were made with different electrode materials (boron doped diamond, platinum, black platinum and gold) which have been tested to determine their capability in recording and/or stimulation. Moreover, with numerical modelling work, we have validated a tridimensional geometry concept with a ground grid which permits a more local stimulation of cells. This thesis has contributed to stabilize different fabrication processes to obtain more repeatable MEA and also to improve their yield. It also allowed the set-up of a follow-up and an experimental protocol to insure MEA traceability and to monitor their performances at each step since their fabrication through means of electrochemical techniques (CV, EIS) to in vitro and in-vivo biological experiments
14
Seresinhe, R. "Impact of aircraft systems within aircraft operation : a MEA trajectory optimisation study." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9261.
Full textAbstract:
Air transport has been a key component of the socio-economic globalisation. The ever increasing demand for air travel and air transport is a testament to the success of the aircraft. But this growing demand presents many challenges. One of which is the environmental impact due to aviation. The scope of the environmental impact of aircraft can be discussed from many viewpoints. This research focuses on the environmental impact due to aircraft operation. Aircraft operation causes many environmental penalties. The most obvious is the fossil fuel based fuel burn and the consequent greenhouse gas emissions. Aircraft operations directly contribute to the CO2 and NOX emissions among others. The dependency on a limited natural resource such as fossil fuel presents the case for fuel optimised operation. The by-products of burning fossil fuel some of which are considered pollutants and greenhouse gases, presents the case for emissions optimised operations. Moreover, when considering the local impact of aircraft operation, aircraft noise is recognised as a pollutant. Hence noise optimised aircraft operation needs to be considered with regards to local impacts. It is clear whichever the objective is, optimised operation is key to improving the efficiency of the aircraft. The operational penalties have many different contributors. The most obvious of which is the way an aircraft is flown. This covers the scope of aircraft trajectory and trajectory optimisation. However, the design of the aircraft contributes to the operational penalties as well. For example the more-electric aircraft is an improvement over the conventional aircraft in terms of overall efficiency. It has been proven by many studies that the more-electric concept is more fuel efficient than a comparable conventional aircraft. The classical approach to aircraft trajectory optimisation does not account for the fuel penalties caused due to airframe systems operation. Hence the classical approach cannot define a conventional aircraft from a more-electric aircraft. With the more-electric aircraft expected to be more fuel efficient it was clear that optimal operation for the two concepts would be different. This research presents a methodology that can be used to study optimised trajectories for more-electric aircraft. The study present preliminary evidence of the environmental impact due to airframe systems operation and establishes the basis for an enhanced approach to aircraft trajectory optimisation which include airframe system penalties within the optimisation loop. It then presents a suite of models, the individual modelling approaches and the validation to conduct the study. Finally the research presents analysis and comparisons between the classical approach where the aircraft has no penalty due to systems, the conventional aircraft and the more-electric aircraft. When the case studies were optimised for the minimum fuel burn operation, the conventional airframe systems accounted for a 16.6% increase in fuel burn for a short haul flight and 6.24% increase in fuel burn for a long haul flight. Compared to the conventional aircraft, the more electric aircraft had a 9.9% lower fuel burn in the short haul flight and 5.35% lower fuel burn in the long haul flight. However, the key result was that the optimised operation for the moreelectric aircraft was significantly different than the conventional aircraft. Hence this research contributes by presenting a methodology to bridge the gap between theoretical and real aircraft-applicable trajectory optimisation.
15
Torabzadeh-Tari, Mohsen. "Dimensioning Tools of MEA Actuator Systems, Including Modeling, Analysis and Technology Comparison." Doctoral thesis, Stockholm : Elektrotekniska system, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9727.
Full text
16
Bertacco, Daniele <1976>. "Mea logica, vera logica: il metodo cartesiano e i fatti della ragione." Doctoral thesis, Università Ca' Foscari Venezia, 2004. http://hdl.handle.net/10579/807.
Full textAbstract:
Questo lavoro può essere letto come il convergere di due percorsi distinti, l'uno soprattutto
storico, l'altro più prettamente teorico, verso un'interpretazione del Cogito cartesiano come "fatto
della ragione".
Il percorso storico, che coincide con i primi tre capitoli, intende ricostruire il rifiuto cartesiano
della tradizione aristotelico-scolastica, nozione che proprio dal punto di vista storico resta
sottodeterminata, ma d'altra parte è questo un limite che si deve imputare allo stesso Descartes; ho
analizzato dunque quest'unica operazione cartesiana distinguendo in essa tre movimenti
profondamente solidali e complementari: il passaggio dalla logica al metodo, quello dalla verità
come convenienza di soggetto e predicato (correttezza di un giudizio) alla verità come evidenza
(imporsi della semplice presenza all'intuito), e quello dal principio di non contraddizione al Cogito.
Soprattutto il primo movimento è degno della massima attenzione, perché nella sostituzione del
metodo alla logica non si esprime solamente l'adozione di un diverso apparato di regole per la
costruzione del sapere, ma più fondamentalmente l'imporsi di una nuova prospettiva: non più lo
"sguardo assoluto" del logico che pretende di scorgere dall'alto la trama puramente formale del
mondo, ma l'esercizio pratico di una razionalità concretamente situata in questo mondo che deve
conoscere.
Il percorso teorico si sviluppa invece nei capitoli quarto e quinto, per saggiare la consistenza e la
solidità della filosofia cartesiana attraverso il confronto con le due critiche più strutturali di cui essa
è oggetto nel dibattito attuale, vale a dire le questioni del dualismo e dello psicologismo. Anziché
essere il "residuo di un presupposto volgare" (come vuole Bontadini), il dualismo cartesiano viene
letto come la traduzione di un'esperienza irriducibile alla pura teoria, vale a dire la limitatezza del
nostro potere sulle cose, la costitutiva impossibilità che il nostro pensiero (a differenza di quello
divino) si traduca immediatamente in un mondo reale, dovendo piuttosto fare i conti con quanto è
già dato (con una chiaro riferimento alla distinzione kantiana tra intuitus derivativus e intuìtus
originarius). La questione dello psicologismo, poi, viene riaperta in considerazione delle difficoltà
in cui si avvolge la stessa critica anti-psicologistica (qui analizzata nelle versioni di Frege e
Husserl); abbandonando per un momento l'itinerario cartesiano, è ancora in una figura kantiana,
quella dei "fatti della ragione", che viene indicata una soluzione più equilibrata al problema,
distante sia dagli eccessi naturalistici dello psicologismo, sia da quelli formalistici dell'antipsicologismo.
Il sesto e conclusivo capitolo, come accennato in apertura, costituisce allora il culmine e il punto
d'incontro dei due percorsi, poiché la lettura del Cogito come un "fatto della ragione" (che segue ad
uno status quaestionis breve, ma già ricco di spunti) da un lato conferma e illustra in qualità di
esempio paradigmatico le tesi più generali emerse nei tre capitoli di ricostruzione storica (rifiuto
della logica; esaltazione dell'evidenza intuitiva come primo ed essenziale requisito della verità;
rifiuto di un principio che sia puramente formale), e dall'altro giustifica la pertinenza degli excursus
teorici condotti nei capitoli 4 e 5, poiché mostra come alcune suggestioni kantiane siano
effettivamente in grado di gettare maggiore luce sulla filosofia di Descartes, e in particolare sul suo
"punto archimedeo".
This work can be seen as composed by two different routes, the one mainly historical, the other
one more genuinely theoretical, converging towards an interpretation of the Cartesian Cogito as a
"fact of reason".The historical route, which corresponds to the first three chapters, is meant to reconstruct the
Cartesian refusal of the Aristotelian-scholastic tradition (just from a historical point of view, this
notion is left under-determined; this limit, however, is due to Descartes himself); I analysed this
single operation, marking out three strongly united and complementary movements: the passing
from logic to method, that from truth as convenience of subject and predicate (correctness of a
judgement) to truth as evidence (self-imposing of the pure presence to the intuition), and that from
the principle of non-contradiction to the Cogito. Especially the first movement is worth the
maximum attention, because the substitution of method for logic expresses not only the adoption of
a different set of rules in order to build up knowledge, but more basically the imposing of a new
perspective: no more the "absolute eye" of the logic, who pretend to see from above the purely
formal texture of the world, but the practical exercise of a rationality which is concretely placed into
this world that must be known.
The theoretical route, on the other hand, develops in chapter 4 and 5, and its aim is to test the
firmness of Cartesian philosophy through a confrontation with the two more structural criticisms on
it: dualism and psychologism. Instead of being the "trace of a vulgar presupposition" (as Bontadini
said), Cartesian dualism is seen as the expression of an experience which can never be reduced to
pure theory, i.e. the limits of our power over things, the essential impossibility for our thinking
(unlike God's thinking) to be at once a real world, because it has what is already given to reckon
with (this point clearly refers to Kantian distinction between intuitus derivativus and intuitus
originarius). The question of psychologism, then, has been renewed because of the troubles in
which anti-psychologistic criticism itself gets entangled (I analysed here the examples of Frege and
Husserl); diverting for a while from my Cartesian course, I point to another Kantian figure, the
"facts of reason", to find out a well-balanced solution of the problem, far from the naturalistic
excess of psychologism as well as from the formalistic excess of anti-psychologism.
The final chapter, as I mentioned at the beginning, represents therefore the apex and the meeting
point of the two routes, because the reading of the Cogito as a "fact of reason" (after a short but
stimulating status quaestionis) on the one hand confirms and illustrates as an exemplary case the
general thesis coming out from the three historical chapters (refusal of logic; exaltation of the
intuitive evidence as the first and essential requirement for truth; refusal of a merely formal
principle); on the other hand, it justifies the pertinence of the theoretical excursus in chapter 4 and
5, because it shows that some Kantian suggestions are actually of great help in understanding
Descartes, and in particular his "Archimedean point".
17
Achet-Haushalter, Marie. "DVLCEDO MEA SANCTA. Penser, expérimenter, communiquer la douceur dans le christianisme antique." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUL001.
Full textAbstract:
Cette étude propose une approche du christianisme antique selon une perspective d’histoire des sensibilités. La douceur est très présente dans les sources chrétiennes antiques, pour décrire un ressenti sensoriel ou affectif éprouvé dans les différents champs de l’expérience religieuse : rituels sacramentels, liturgie, émotions collectives, mais aussi dans le contact avec la Bible, ou dans une forme d’expérience intérieure directe du divin. Nous nous sommes intéressés aux diverses manières dont ce vécu est exprimé et interprété, aux pratiques concrètes auxquelles il peut être relié, mais aussi au regard porté sur la douceur du point de vue des normes morales, ainsi qu’au rôle accordé à celle-ci dans la pédagogie déployée par les prédicateurs à l’égard des fidèles. Nous avons ainsi mis en lumière la dimension sensible et affective de l’expérience religieuse des chrétiens de l’Antiquité, et la valorisation dont la sensibilité fait l’objet, au regard des conceptions antiques, annonçant ainsi le Moyen ÂgeThis study approaches Ancient Christianity from the perspective of the history of sensibilities. Sweetness is very present in ancient Christian sources, to describe a sensory or affective feeling experienced in the various fields of religious experience: sacramental rituals, liturgy, collective emotions, but also in contact with the Bible, or in a form of direct inner experience of the divine. We are interested in the various ways in which this experience is expressed and interpreted, the concrete practices to which it can be linked, but also the way in which sweetness is viewed from the point of view of moral standards, and the role given to it in the pedagogy deployed by preachers towards the Christians. In this way, we have highlighted the sensitive and affective dimensions of the religious experience of ancient Christians, and the way in which sensitivity is valued in relation to ancient conceptions, thus heralding the Middle Ages
18
Barath, Peter. "Palivové články H2-O2 s anexovou a bipolární membránou." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233426.
Full textAbstract:
The doctoral thesis deals with investigation of the catalysts and ionexchanege membranes for fuel cells H2-O2. The work contains the basic principles of chemical reactions, thermodynamic aspects and kinetic properties in PEM fuel cells.Ion-exchagers based on fluorinated polymer sulfonic acids known as NAFION are used in most cases. These compounds are very expensive. Also a strong corrosive attribute requires platinum as a catalysator. These facts make the membrane fuel cells fully non-competetive with e.g. internal combustion engine in spite of all ecological advantages of this electrical power source. The subject of doctoral thesis is research and development of compounds for the composite electrode materials base on NiOx, Ni-Pd and Raney Ni suitable as catalysts a nd alkaline or bipolar ionexchange membranes for electrochemical fuel cells.
19
Muzhong, Shen. "Novel MEA application and performance modelling of the direct methanol fuel cell (DMFC)." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427322.
Full text
20
Horton, Paul Michael. "Investigating information processing within the brain using multi-electrode array (MEA) electrophysiology data." Thesis, University of Sussex, 2011. http://sro.sussex.ac.uk/id/eprint/6929/.
Full textAbstract:
How a stimulus, such as an odour, is represented in the brain is one of the main questions in neuroscience. It is becoming clearer that information is encoded by a population of neurons, but, how the spiking activity of a population of neurons conveys this information is unknown. Several population coding hypotheses have formulated over the years, and therefore, to obtain a more definitive answer as to how a population of neurons represents stimulus information we need to test, i.e. support or falsify, each of the hypotheses. One way of addressing these hypotheses is to record and analyse the activity of multiple individual neurons from the brain of a test subject when a stimulus is, and is not, presented. With the advent of multi electrode arrays (MEA) we can now record such activity. However, before we can investigate/test the population coding hypotheses using such recordings, we need to determine the number of neurons recorded by the MEA and their spiking activity, after spike detection, using an automatic spike sorting algorithm (we refer to the spiking activity of the neurons extracted from the MEA recordings as MEA sorted data). While there are many automatic spike sorting methods available, they have limitations. In addition, we are lacking methods to test/investigate the population coding hypotheses in detail using the MEA sorted data. That is, methods that show whether neurons respond in a hypothesised way and, if they do, shows how the stimulus is represented within the recorded area. Thus, in this thesis, we were motivated to, firstly, develop a new automatic spike sorting method, which avoids the limitations of other methods. We validated our method using simulated and biological data. In addition, we found our method can perform better than other standard methods. We next focused on the population rate coding hypothesis (i.e. the hypothesis that information is conveyed in the number of spikes fired by a pop- ulation of neurons within a relevant time period). More specifically, we developed a method for testing/investigating the population rate coding hypothesis using the MEA sorted data. That is, a method that uses the multi variate analysis of variance (MANOVA) test, where we modified its output, to show the most responsive subar- eas within the recorded area. We validated this using simulated and biological data. Finally, we investigated whether noise correlation between neurons (i.e. correlations in the trial to trial variability of the response of neurons to the same stimulus) in a rat's olfactory bulb can affect the amount of information a population rate code conveys about a set of stimuli. We found that noise correlation between neurons was predominately positive, which, ultimately, reduced the amount of information a population containing >45 neurons could convey about the stimuli by ~30%.
21
Ma, Jia. "Development of Cost-Effective Membrane-Electrode-Assembly (MEA) for Direct Borohydride Fuel Cells." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1326302289.
Full text
22
Chiewudomrat, Suttiya. "Optical characterization of gradient in droplets : application to CO2 capture by MEA spray." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR07.
Full textAbstract:
Les sprays réactifs peuvent être trouvés dans de nombreuses applications industrielles. La caractérisation de l'état transitoire pour des gouttes est un défi, elle nécessite la mesure de la température et / ou des gradients de composition dans des gouttes. Dans cette thèse, la technique d'arc en ciel globale est étendue pour pouvoir quantifier l'évolution des gradients. Après l'étude numérique des caractéristiques de l'arc-en-ciel diffusé par goutte à gradient d'indice de réfraction radial, une étude expérimentale est réalisée pour le cas particulier de la capture du CO2 par des gouttes de MEA. Il a été démontré que des gradients de concentration peuvent être quantifiés lors des premiers instants de la mise en contact des gouttes avec le dioxyde de carbone. Après un temps de contact suffisamment long, l'analyse de la mesure d'arc en ciel globale basée sur des gouttes avec ou sans gradients révèle un comportement identiqueReactive sprays can be found in numerous industries. The characterization of transient state for such droplets is a challenge, asks for the measurement of temperature and/or composition gradients inside the droplets. In this thesis, Global Rainbow Technique (GRT) is extended to be able to quantify the behavior of gradients. After the numerically studied on the characteristics of rainbow scattered by droplet with radial refractive index gradients, an experimental study is carried out for the particular case of CO2 capture by MEA droplets. According to the investigation, it is demonstrated that the gradients can be quantified during the first moments of injection. The analysis of GRT measurement based on the droplet with or without gradients indicates the identical behavior when the reacting time is long enough
23
Arango, Munoz Paty. "Stripper Modification of a Standard MEA Process for Heat Integration with a Pulp Mill." Thesis, KTH, Kemiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-289162.
Full textAbstract:
De 20 största massabruken i Sverige släpper tillsammans ut ungefär 20 miljoner ton CO2 per år. Dessa utsläpp har biogent ursprung och anses därför vara klimatneutrala. Massa- och pappersindustrin är därmed en lämplig kandidat för implementeringen av BECCS (eng. Bioenergy with Carbon Capture and Storage) och har en betydande potential att nå de, av den svenska regeringen, uppsatta klimatmålen som säger att Sverige inte ska några nettoutsläpp av växthusgaser till atmosfären senast år 2045. I detta examensarbete simulerades kemiska absorptions- och desorptionsprocesser med MEA som lösningsmedel genom att tillämpa den hastighetsbaserade metoden i en rigorös modell i Aspen Plus. Stripper- och absorptionsmodellerna validerades innan standardprocessen modifierades till en konfiguration som möjliggör värmeintegration av koldioxidinfångningens överskottsvärme med, exempelvis, ett sulfatmassabruk. Avskiljningsgraden och laddning hos den mättade lösningen användes som prestandaindikatorer för att validera absorptionskolonnerna. Återkokarens energiåtgång och laddning hos den omättade lösningen användes somprestandaindikatorer för att validera stripperkolonnerna. Samtliga kolonner dimensionerades för att erhålla 90 vikt% avskiljningsgrad. Olika flödeshastigheter av lösningsmedlet testades för att säkerställa effektivt nyttjande av packningen i absorptions- och stripperkolonnerna. Lämpliga temperaturnivåer för värmeintegration, inom och utanför, koldioxidinfångningen erhölls genom att utvärdera olika varianter av en stripper-overhead-kompression konfiguration. Utvärderingen av den modifierade MEA processen tog hänsyn till potentialen för ångbesparing och energieffektivisering. Resultat från simuleringarna tyder på att den modifierade strippern skulle kunna ge besparingar på upp emot 11 % i ånganvändning. Energibesparingar i samma storleksordning kunde även erhållas genom värmeintegration mellan koldioxidinfångningen och en särskild process i ett referensbruk. Implementering av BECCS-konceptet på det här sättet skulle därmed kunna bli ett mer attraktivt alternativ för den svenska massa- och pappersindustrin att bekämpa klimatförändringarna.The 20 largest pulp mills in Sweden emit around 20 million tonnes of CO2 per year. These emissions are considered carbon-neutral since they originate from biogenic sources. The pulp and paper industry is therefore a good candidate for the application of BECCS (Bioenergy with Carbon Capture and Storage) and has the potential to play a significant role for reaching the long-term mitigation target set by the Swedish government that Sweden should be climate-neutral by year 2045. In this thesis, a MEA-based chemical absorption and desorption process was rigorously modelled in Aspen Plus using the rate-based method. Validation of the absorber and stripper model was conducted before the standard process was modified to a configuration that enables heat integration of a significant amount of excess heat from the capture process in, for example, a Kraft pulp mill. CO2 removal rate and rich solvent loading were used as performance indicators to validate the absorber columns. The reboiler duty and lean solvent loading served as performance indicators in the stripper validation. The columns were dimensioned considering 90 wt% capture rate. Efficient use of the entire packing in the absorber and stripper columns was ensured by testing different solvent flow rates. Suitable temperature levels for heat integration, within and across the capture plant, were obtained through an assessment of different versions of a stripper overhead compression configuration. The evaluation of the modified MEA processes took into account the steam conservation potential and energy efficiency potential. The simulation results indicate that the modified stripper may lead to savings of up to 11% in steam consumption. Heat integration between the capture plant and a specific process in a reference Kraft pulp mill resulted in energy savings of the same order of magnitude. Thereby, making the BECCS concept a more attractive solution for the Swedish pulp and paper industry to mitigate climate change.
24
Sutherland, Richard Daniel. "Performance of different proton exchange membrane water electrolyser components / cRichard Daniel Sutherland." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9214.
Full textAbstract:
Water electrolysis is one of the first methods used to generate hydrogen and is thus not considered to be a new technology. With advances in proton exchange membrane technology and the global tendency to implement renewable energy, the technology of water electrolysis by implementation of proton exchange membrane as solid electrolyte has developed into a major field of research over the last decade. To gain an understanding of different components of the electrolyser it is best to conduct a performance analysis based on hydrogen production rates and polarisation curves. The study aim was to compare the technologies of membrane electrode assembly with gas diffusion electrode and the proton exchange membranes of Nafion® and polybenzimidazole in a commercial water electrolyser. To determine which of the components are best suited for the process a laboratory scale electrolyser was to be used to replicate the commercially scaled performance. The effect of feed water contaminants on electrolyser performance was also investigated by introducing iron and magnesium salt solutions and aqueous methanol solutions in the feed reservoir. Components to be tested included different PEM types as well as the base component on which the electrocatalyst layer is applied. The proton exchange membranes compared were standard Nafion® N117 and polybenzimidazole meta-sulfone sulfonated polyphenyl sulfone (PBI-sPSU). A laboratory scale electrolyser from Giner Electrochemical Systems was utilised where different components were tested and compared with one another. Experimental results with commercial membrane electrode assemblies and gas diffusion electrodes demonstrated the influence of temperature on electrolyser performance for the proton exchange membranes, where energy efficiency increased with temperature. The effect of pressure was insignificant over the selected pressure range. Comparison of membrane electrode assembly and gas diffusion electrode technologies showed enhanced performance from MEA technology, this was most likely due to superior electrocatalyst contact with the PEM. Results of synthesised Nafion® N117 and PBI-sPSU MEA showed increased performance for PBI-sPSU, but it was found to be more susceptible to damage under severe conditions. The effect of metal cations in the supply reservoir exhibited reduced energy efficiencies and increased specific energy consumption for the test duration. Treatment with sulphuric acid was found to partially restore membrane electrode assembly performance, though it is believed that permanent damage was inflicted on the membrane electrode assembly electrocatalyst. Use of aqueous methanol solutions were found to increase electrolyser performance. It was also found that aqueous methanol electrolysis occurs at lower current densities, whereas a combination of aqueous methanol and water electrolysis occurred at higher current densities depending on the concentration of methanol.Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.
25
DAS, VIVEK. "LEVERAGING TRANSCRIPTOMIC ANALYSIS TO IDENTIFY TRANSCRIPTION FACTORS ORCHESTRATING CANCER PROGRESSION." Doctoral thesis, Università degli Studi di Milano, 2018. http://hdl.handle.net/2434/559711.
Full textAbstract:
Next generation sequencing (NGS) technology is currently employed to explore the molecular profiles associated to different biological contexts. The application of this technology provides at same time a high-resolution and global view of the genome and epigenome phenomena, enabling us to study the molecular events underlying many human diseases, including cancer. Our lab tries to exploit the utility of high throughput sequencing technologies generating genomic, transcriptomic and epigenomic data from patient's cohort to study the underlying molecular mechanisms that characterize the specific diseases and map the key regulators that can be critical targets for relevant therapeutic measures. I take the advantage of this technology to mainly understand two aggressive cancers: Ovarian Cancer (OC) and Glioblastoma multiforme (GBM).
OC is a leading cause of cancer-related death for which no significant therapeutic progress has been made in the last decades. Also, in this case, despite multimodal treatment its prognosis remains extremely poor. This is due to the fact that the molecular mechanisms underlying OC tumorigenesis and progression are still poorly understood (Vaughan et al., 2011). GBM is the most common and aggressive primary brain malignancy with very poor prognosis (Frattini et al., 2013). The median survival rate is of 12-15 months (Singh et al., 2012) with 5-year survival that is less than 5% despite the multimodal treatment which include surgery, radiotherapy and chemotherapy. To this end, I will be integrating various genomic and transcriptomic analysis to define the key regulatory actors that characterize the disease progression paving. This integrated analysis has been devised in form of a computational workflow that gives way for a discovery pipeline for physiopathologically meaningful epigenetic targets that can lead to therapies.
26
Cruz, Valdecy Aparecida Rocha da. "Avalia??o de curvas de postura de uma linha f?mea de frango de corte." UFVJM, 2010. http://acervo.ufvjm.edu.br/jspui/handle/1/782.
Full textAbstract:
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-12-22T11:29:16Z
No. of bitstreams: 2
valdecy_aparecida_rocha_cruz.pdf: 267581 bytes, checksum: 1e59b25dbde1c757d85d3e2e0af0d778 (MD5)
license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-12-22T12:50:57Z (GMT) No. of bitstreams: 2 valdecy_aparecida_rocha_cruz.pdf: 267581 bytes, checksum: 1e59b25dbde1c757d85d3e2e0af0d778 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)
Made available in DSpace on 2015-12-22T12:50:57Z (GMT). No. of bitstreams: 2 valdecy_aparecida_rocha_cruz.pdf: 267581 bytes, checksum: 1e59b25dbde1c757d85d3e2e0af0d778 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2010
Estimativas precisas e acuradas de par?metros gen?ticos e fenot?picos s?o de grande import?ncia para se alcan?ar progresso gen?tico em uma popula??o e se selecionar, de forma mais eficiente, os indiv?duos das linhagens espec?ficas nos programas de melhoramento gen?tico. Com isso, objetivou-se com este trabalho estimar os par?metros da curva de postura, utilizando os modelos de polin?mios segmentados e Wood (1967); e estimar par?metros gen?ticos e fenot?picos dos par?metros do modelo de polin?mios segmentados, assim como a tend?ncia gen?tica dos mesmos. Foram utilizados dados da produ??o de ovo semanal das 25 at? 64 semanas de idade provenientes de 2.398 aves de uma linha f?mea de frangos de corte. As curvas de postura foram ajustadas utilizando os modelos de polin?mios segmentados e Wood (1967). O modelo de polin?mios segmentados ? constitu?do pelos par?metros ?xp?- idade das aves ao pico de postura, ?P?- n?vel de produ??o no pico, ?s? - taxa de decr?scimo semanal na produ??o de ovos ap?s o pico, e ?t? - tempo entre o in?cio e o pico de postura. O modelo de Wood ? constitu?do pelos par?metros ?a? - taxa de produ??o inicial, ?b? taxa de acr?scimo at? o pico de produ??o, e ?c? taxa de decr?scimo ap?s o pico de produ??o. As estimativas das m?dias dos par?metros das curvas foram realizadas utilizando o PROC MEANS do SAS. A estima??o dos componentes de covari?ncias, herdabilidades, correla??es e os valores gen?ticos para os par?metros da curva de postura de polin?mios segmentados foram obtidas utilizando o ?software? MTDFREML e as tend?ncias gen?ticas por meio do PROC REG do SAS. A linhagem avaliada apresentou um pico de postura ?s 30,43 semanas de idade, sendo o n?vel de postura de 0,746 ovo/aves/dia, com uma m?dia de 3,08 semanas do in?cio da postura at? o pico de postura e a taxa de persist?ncia foi de 0,014 ovo/ave/semana. As m?dias estimadas para os par?metros do modelo de Wood (1967) foram de 0,0003 para taxa de produ??o inicial 2,9398 para taxa de acr?scimo de produ??o at? o pico e de 0,0767 para taxa de decr?scimo de produ??o ap?s o pico postura. As curvas ajustadas para os modelos de polin?mios segmentados e Wood (1967) permitiram evidenciar um baixo n?vel de produ??o no pico de postura. O modelo de polin?mios segmentados superestimou a persist?ncia ap?s o pico de postura e o modelo de Wood (1967) subestimou o final da produ??o. As m?dias das herdabilidades foram de baixa a m?dia magnitudes, 0,25 (xp), 0,18 (P), 0,17 (s) e 0,10 (t). Estes resultados indicam que a sele??o para o par?metro ?xp? teria uma melhor resposta que para os demais par?metros. As correla??es entre o par?metro ?t? e os demais par?metros da curva foram positivas variando de 0,21 at? 1,00. Essas correla??es indicam que os animais com um maior tempo entre in?cio e pico de postura tendem a apresentar uma maior idade ao pico de postura, maior n?vel de produ??o e maior queda de produ??o p?s-pico. As correla??es foram negativas entre os par?metros ?s? e ?xp? e ?s? e ?P? apresentando-se menor entre ?s? e ?xp? (-0,17) e maior entre ?s? e ?P? (-0,91), indicando que um aumento no n?vel de produ??o e idade ao pico de produ??o acarretaria uma menor queda de produ??o de ovos p?s-pico. Podemos constatar que pode ser promovido ganho gen?tico para os par?metros da curva de produ??o de ovos, por?m a sele??o para um aumento do n?vel de produ??o poder? levar a um aumento na idade ao pico de postura. Assim como, aves mais precoces ao pico poder?o apresentar menor persist?ncia.
Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2010.
ABSTRACT Precise and accurate estimates of genetic and phenotypic parameters are of great importance to achieve genetic progress in a population and select more efficiently individuals of specific lines in breeding programs. Thus, the aim with this study was to estimate the parameters of the curve approach, using models of segmented polynomials and Wood (1967) and to estimate genetic and phenotypic parameters of the model parameters of segmented polynomials, as well as the genetic tendency of them. It had been used data from the weekly egg production from 2,398 birds in a line of female broilers, aging from 25 to 64 weeks. The curves of posture were adjusted using the models of segmented polynomials and Wood (1967). The segmented polynomial model consists of parameters "xp" - the peak age of the birds in attitude, "P" - at peak production level, "s"- a weekly rate of decrease in egg production after peak, and ?t? - time between onset and peak position. The parameters of the Wood model consist of "a"- rate initial production," b "rate of increase until the production peak, and "c" rate of decline after peak production. Estimates of means of parameters were performed using SAS PROC MEANS. Estimation of covariance components, heritability?s, correlations and breeding values for the parameters of the curve posture segmented polynomial were obtained using the software MTDFREML and genetic trends by PROC REG of SAS. The strain studied showed a peak position at 30.43 weeks of age, the level of posture of 0.746 egg / poultry / day, with an average of 3.08 weeks of posture to the peak position and the rate of persistence was 0.014 eggs / bird / week. The estimated averages for the parameters of the model of Wood (1967) was 0.0003 for rate initial production rate of 2.9398 for increased production to peak and 0.0767 for rate of decline of production after the peak position . The fitted curves for the models of segmented polynomials and Wood (1967) have highlighted a low level of production at peak production. The segmented polynomial model overestimated the persistence after the peak position and the model of Wood (1967) underestimated the final production. The heritability?s means were low to medium magnitude, 0.25 (xp), 0.18 (P), 0.17 (s) and 0.10 (t). These results indicate that selection for the parameter "xp" would have a better response than for the other parameters. The correlations between the parameter "t" and the other parameters of the curve were positive ranging from 0.21 to 1.00. These correlations indicate that animals with a longer time between onset and peak position tend to have a higher age at peak position, the highest level of production and greater decrease in post-peak production. Were negative correlations between the parameters "s" and "xp" and "s" and "P" presenting lower between "s" and "xp" (-0.17) and higher in "s" and "P" (-0.91), indicating that an increase in production level and age at peak production would result in a smaller drop in egg production after peak. It has been noted that genetic gains can be obtained for the curve parameters for egg production, but a selection focused on an increased level of production could lead to an increase in age at peak production. Just as birds that present earlier peak may have lower persistence.
27
Andrade, Alexandre Bodart de. "Desenvolvimento de conjuntos eletrodo-membrana-eletrodo para células a combustível a membrana trocadora de prótons (PEMFC) por impressão à tela." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-17082009-103451/.
Full textAbstract:
O processo de Impressão à Tela foi desenvolvido neste trabalho para ser aplicável à deposição de camadas catalíticas em eletrólitos utilizados em PEMFC. Inicialmente foram construídos conjuntos eletrodos-membrana (MEAs) de 25 cm2 de área ativa e comparados com outros produzidos pelo método de Aspersão. Os dois métodos produziram MEAs que apresentaram densidades de corrente acima de 600 mA.cm-2 a 600 mV. Foi conduzido um estudo para o aumento de escala do MEA para 144 cm2 de área ativa. Para este fim, foi projetada uma célula para abrigar os MEAs destas dimensões. Neste projeto, o perfil dos canais de distribuição de gás foi desenvolvido através da ferramenta de fluido dinâmica computacional Comsol Multiphysics, sendo que, para o projeto das placas componentes da célula foi utilizado o AutoCAD. Os MEAs de 144 cm2 confeccionados por Aspersão e por Impressão à Tela foram confrontados com MEAs comerciais de iguais dimensões. Estes apresentaram melhor desempenho a 600 mV, entretanto são mais custosos que a solução desenvolvida neste estudo. O novo método apresentou-se adequado para a confecção de MEAs de baixo custo de diferentes geometrias e para a produção de lotes a serem utilizados em pequenos módulos de potência.The Sieve Printing process was studied in this work to apply the catalyst layers onto electrolytes utilized in PEMFC. Initially, 25 cm2 active area MEAs were built for comparison with others MEAs produced by the Spray technique. The two methods produced MEAs that showed current densities higher than 600 mA.cm-2 at 600 mV. A scaling up study for 144 cm2 of active area MEAs was carried out. For this purpose, a new cell had to be projected for shelter the MEAs in such dimensions. The profile of the gas distribution channels was developed through the computational fluid dynamic tool Comsol Multiphysics. For the design of the bipolar plates of the cell the AutoCAD was used. The 144 cm2 MEAs made by Spray and by Sieve Printing methods were confronted with commercials MEAs ones of equal dimensions. These commercials MEAs presented better performance at 600 mV, however they were more costly than the solution developed in this study. The new method was showed to be adequate to fabricate low cost MEAs of different geometries and to produce any amount of MEAs for small scale stacks (up to 10 kW).
28
Wallace, Jamie Stuart. "Development of a Carbon Dioxide Continuous Scrubber (CDOCS) System for Alkaline Fuel Cells." Thesis, University of Canterbury. Mechanical Engineering, 2006. http://hdl.handle.net/10092/1077.
Full textAbstract:
Alkaline fuel cells (AFC's) using renewable fuels are a developing technology capable of meeting market niches in standby, standalone and distributed power generation. AFC's generate electricity, heat and water using hydrogen and oxygen as fuels. While AFC's have been known and the principles demonstrated for over sixty years, their use has been restricted primarily to space applications. Recent technological developments have seen the cost of AFC stacks fall considerably; this together with several other advantages over competing fuel cell technology, has rekindled interest in commercial systems. The main deterrent to wide spread commercialisation of AFC systems is susceptibility to carbon dioxide (CO2) in atmospheric air used as the oxygen supply. AFC's require a low cost, low energy, continuous scrubbing device to reduce CO2 in air from approximately 380 parts per million (ppm) atmospheric concentration to below 50 ppm. Current technology to overcome this problem, a solid expendable absorbent called soda lime, is not viable for commercial systems. The project scope included concept generation of a device to remove CO2 from air, the development of a CO2 measurement technique, investigation of chemistry and flow phenomena to determine design relations, and product design and embodiment. The scrubber system conceived specifically for AFC systems uses the temperature swing chemistry of a liquid chemical absorbent, monoethanolamine, and a packed bubble column apparatus to provide intimate gas-liquid interaction. Prototype development proved the Carbon Dioxide Continuous Scrubber (CDOCS) concept and a Patent Cooperation Treaty (PCT) patent was granted, followed by a full American patent. A gas chromatographic measurement technique was developed to measure low ppm concentration CO2 in air, enabling regular monitoring of scrubbed gas. Carbon dioxide was separated from a small sample of scrubbed air by chromatographic columns, and the gases analysed with a thermal conductivity detector. The GC system was capable of measuring to 10 ppm with good resolution and accuracy. Experimental studies were carried out to characterise the flow dynamics and absorption phenomena in the packed bubble column absorber. The relationship between absorption performance and gas-liquid contact time, an important operating parameter for use with AFC's, was theoretically determined and later confirmed by experiment. The regeneration process was studied and the optimal regenerator design determined to be second, smaller packed bubble column. Experiments were conducted to establish design relations for regeneration temperature, flush gas flow rate and the effect of multiple regeneration cycles. A prototype CDOCS system was built to enable experimental characterisation of scrubbing performance as a function of primary design and operating parameters including liquid depth, regenerator operating temperature and solution composition. This resulted in a good understanding of the system, and an optimised experimental run was performed for cost and performance comparison to existing scrubbing technology. The CDOCS was capable of reducing CO2 in air from 380 to 80 ppm for thirty days, providing low cost, low maintenance scrubbing compared to soda lime. The capital cost of the CDOCS is considerably more than for soda lime scrubbers, and the penalty for extended operation is parasitic power consumption by the CDOCS system totalling less than 7% of fuel cell output. It is suggested that a combination of the two technologies be used initially to provide effective, low cost scrubbing for AFC and CDOCS co-development. Future work on the CDOCS project should include reduction of chemical vapour carry over to the fuel cell, followed by integration with an AFC system. This would allow further development, refinement and design for production to reduce capital cost.
29
DOSSI, ELENA. "Functional regeneration of the meso-cortico-limbic dopaminergic system as a model to study novel neuroreparative strategies." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/27833.
Full textAbstract:
Dopaminergic neurons in the VTA send projections to different forebrain structures, forming a complex crucial neuromodulatory system. Prefrontal, orbitofrontal and cingulated cortices receive the most marked innervation from the VTA; projections from the VTA to the medial prefrontal cortex (mPFC) constitute a portion of the mesocortical dopamine system. Much of this connectivity is bidirectional. Furthermore, the mesocortical dopamine system is involved in a great variety of brain functions, such as working memory, attention selection and memory retrieval, because of its interconnections with brain areas processing external information as well as internal information (Miller et al., 2002).
Dopaminergic afferents from the mesencephalon seem to have a crucial role in the normal development of the PFC as well as in the regulation of neuronal activity in this brain area (Lewis et al., 1998). In fact, an abnormal maturation and alterations of the mesocortical projections to the PFC have been suggested to be involved in the development of psychostimulant-induced sensitization and in the pathophysiology of several disorders, such as schizophrenia, addiction or attention- deficit/hyperactivity disorder. The analysis of the formation and development of functional connections in the Central Nervous System needs suitable model systems to understand the basic, functional mechanisms (Hofmann et al., 2004). We have reconstructed parts of the mesocorticolimbic dopaminergic system using the model of organotypic co-cultures of tissue slices from the VTA/SN-complex and the PFC. In fact, organotypic brain slices are closer to the in vivo situation than cell cultures and they represent the most intact culture system for studying cortex function in isolation (Gähwiler et al., 1997; Karpiak and Plenz, 2002; Stewart and Plenz, 2008); furthermore, by combining organotypic cultures with microelectrode array (MEA) recordings, it is possible to simultaneously and repeatedly perform extracellular, non-invasive, multi-site recordings from electrodes covering the whole preparation, and to monitor long- term processes of neurite outgrowth and development and synapse formation at a functional level (Egert et al., 1998; Beggs and Plenz, 2003 and 2004; Hofmann et al., 2004).
The aim of the present study was to characterize the developmental features of the VTA/SN-PFC co-cultures maintained on multielectrode array platforms, in order to study the functionality of the neuronal projections which have been demonstrated to grow in vitro between the two areas of the cultures (Franke et al., 2003; Heine et al., 2007). Furthermore, we validated the system as an useful pharmacological tool to study the effects of different neuromodulatory substances.
30
Rieder, Alexander [Verfasser], and Günter [Akademischer Betreuer] Scheffknecht. "CO2-Abscheidung aus Kraftwerksrauchgasen mit wässriger MEA-Lösung - Waschmitteldegradation und Aufbereitungsverfahren / Alexander Rieder ; Betreuer: Günter Scheffknecht." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1123572453/34.
Full text
31
Araújo, Hugo de Lima. "Mea culpa, mea culpa, mea maxima culpa: neoliberalismo, psicologização e investigação científica." Master's thesis, 2019. https://hdl.handle.net/10216/123833.
Full textAbstract:
Este estudo qualitativo exploratório debruça-se sobre a relação entre o paradigmaneoliberal - materializado nas novas políticas de gestão (NPM) das Universidades - e ofenómeno da psicologização e pretende alertar a comunidade científica e leiga para acrescente instrumentalização da Psicologia e mercantilização do conhecimento,particularmente no seio investigação científica. Como tal, explorou-se a dinâmica defuncionamento do Centro de Psicologia da Universidade do Porto através da análise deconteúdo temática da informação resultante das entrevistas semiestruturadas realizadas adoze investigadores deste centro. A confirmação das questões de investigação permitiuconcluir que, pelas NPM, a ideologia neoliberal imiscui-se na investigação científica,exaltando a tecnocracia e a eficácia como critérios, promovendo os discursospsicologizadores que, por sua vez, ocupam cada vez mais a arena pública. Ademais, aexploração pioneira destes fenómenos num contexto português permitem perceber que,embora exista uma predileção pelos modelos da Psicologia Convencional com diretrizesanglo-americanas, existe uma aposta clara na diversidade de investigação, tanto teórica comometodológica.
32
Araújo, Hugo de Lima. "Mea culpa, mea culpa, mea maxima culpa: neoliberalismo, psicologização e investigação científica." Dissertação, 2019. https://hdl.handle.net/10216/123833.
Full textAbstract:
Este estudo qualitativo exploratório debruça-se sobre a relação entre o paradigmaneoliberal - materializado nas novas políticas de gestão (NPM) das Universidades - e ofenómeno da psicologização e pretende alertar a comunidade científica e leiga para acrescente instrumentalização da Psicologia e mercantilização do conhecimento,particularmente no seio investigação científica. Como tal, explorou-se a dinâmica defuncionamento do Centro de Psicologia da Universidade do Porto através da análise deconteúdo temática da informação resultante das entrevistas semiestruturadas realizadas adoze investigadores deste centro. A confirmação das questões de investigação permitiuconcluir que, pelas NPM, a ideologia neoliberal imiscui-se na investigação científica,exaltando a tecnocracia e a eficácia como critérios, promovendo os discursospsicologizadores que, por sua vez, ocupam cada vez mais a arena pública. Ademais, aexploração pioneira destes fenómenos num contexto português permitem perceber que,embora exista uma predileção pelos modelos da Psicologia Convencional com diretrizesanglo-americanas, existe uma aposta clara na diversidade de investigação, tanto teórica comometodológica.
33
Lai, Ming-De, and 賴明德. "Solubility and diffusivity of (CO2, N2O)in blended alkanolamines (MEA/MDEA, MEA/AMP) aqueous solutions." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/21843240492871445061.
Full text
34
Chen, Yousee, and 陳永富. "Measurements of heat capacity of MEA/MDEA aqueous solutions and enthalpy solution of CO2 in MEA/MDEA aqueous solutions." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/63228654497811839368.
Full textAbstract:
碩士中原大學
化學工程研究所
81
Alkanolamines are extensively used as absorbents for removal of acid gas imputies such as H2S and CO2. In industrial gas trea- ting processes, single amine aqueous solutions are frequently used as absorbents. Recently, the use of blended amines soluti- ons was proposed for removal of acidic gases. The purpose is to retain the advantages of each amine such as high absorption rates and high absorption capacities and to develop more effective abs- orbents. Because the heat capacity and enthalpy of solution of acid gases in alkanolamines are important for the rational desi- gn of heat exchangers involved in the gas removal process. The object of this research was to study experimentally the heat cap- acity of MEA with MDEA aqueous solutions and the enthalpy of sol- ution of CO2 in aqeous mixtures of MEA/MDEA over the temperature range 25°C to 70°C. The differential scanning calorimeter was used for measurem- ents of heat capacity and enthalpy of solution. Calorimetric me- asurements of heat capacity and enthalpy of solution of CO2 in aqueous MEA/MDEA solutions are made over the conditions: (1) Al- kanolamine aqueous solutions: 30 wt% MEA, 24 wt% MEA+6 wt% MDEA, 18 wt% MEA + 12 wt% MDEA, 12 wt% MEA + 18 wt% MDEA, and 6 wt%MEA + 24 wt% MDEA, and 30 wt% MDEA. (2) Temperature range: 25,30,35, 40, 45, 50, 55, 60, 65, and 70°C 。 In this work a systematic and complete study of heat capaci- ty and enthalpy of solution of CO2 in MEA/MDEA aqueous solutions were made. The results will form a useful data base from which the dependence of enthalpy of solution on the temperature, load- ing capacity, and amine concentration can be studied and useful correlations can then be developed. Also, the data can be used for the effective design of the heating load of heat exchangers involved in the absorption units.
35
Boháč, Petr. "Kolářovo mea culpa." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-269874.
Full textAbstract:
Umělecké dílo je možné nahlédnout z několika perspektiva vždy se ukáže jako jiné a zároveň v jinakosti jako podobné. V této nevyjasněnosti - neklidu - vězí krása díla. A přesto každý interpret, sám za sebe i navzdory dílu samotnému, se musí pokusit najít onen kruciální bod, ze kterého bude dílo nahlíženo. Není důležité, dopracuje-li se k tomuto bodu až postupem čtení, až v samotném rozkrývání jednotlivých složek, nebo jestli díky němu do něj vstupuje, aby jej na konci popřel nebo potvrdil. Slouží mu jako kompas při zbloudění i jako ta část mapy, do níž ještě není zanesena krajina, ta bílá místa, která vábí interpreta k doplnění. V této práci se tímto bodem stane skutečná událost, chápaná ve vztahu k básnické řeči, k realitě, k básníku, jenž nahlíží sebe sama i druhého - ve vztahu ke světu, v němž básník žije, do něhož se projektuje, s kterým se vyrovnává, pro který píše, ale i ke světu jakožto unikátnosti básnické řeči, v níž skutečnost mizí. Nahlížení přes optiku skutečné události vyvrcholí v básni Skutečná událost ze sbírky Prométheova játra, jako v ní vrcholí i básnická tvorba Jiřího Koláře.
36
Lai, Ming De, and 賴明德. "Solubility and diffusivity of carbon dioxide and nitrous oxide in blended alkanolamines (MEA/MDEA,MEA/AMP) aqueous solutions." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/36436131171011194989.
Full textAbstract:
碩士中原大學
化學工程研究所
82
The solubility (physical) and diffusivity of acid gases of N2O and CO2 in aqueous MEA (monoethanolamine) / MDEA (N- methyldiethanolamine) solutions and MEA (monoethanolamine) / AMP (2-Amino-2-methyl-1-propanol) solutions have been measured for temperatures 30, 35, and 40℃. The systems studied are 30 wt% MEA, 24 wt% MEA + 6 wt% AMP, 18 wt% MEA + 12 wt% AMP, 12 wt% MEA + 18 wt% AMP, 6 wt% MEA + 24 wt% AMP, 30 wt% AMP, 24 wt% MEA + 6 wt% MDEA, 18 wt% MEA + 12 wt% MDEA, 12 wt% MEA + 18 wt% MDEA, 6 wt% MEA + 24 wt% MDEA, 30 wt% MDEA. The solubility data of N2O in amine solutions were measured in a solubility apparatus. The diffusivity data of N2O in amine aqueous solutions were measured in a wetted wall column apparatus. Using the N2O analogy, the solubility and diffusivity of CO2 in blended amine solutions were estimated. The solubility data obtained in this study were correlated based on the excess Henry's coefficient using the volume fraction as concentration. The results of this study can serve as a valuable data base for efficient design of acid gas treating processes,using blended amine as the absorption fluids.
37
陳妍任. "Measurements of heat capacity of alkanolamine aqueous solutions：MEA/MDEA/H2O, MEA/AMP/H2O, and MEA/2-PE/H2O systems." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/53733395184955910884.
Full textAbstract:
碩士中原大學
化學工程學系
88
Heat capacities of aqueous mixtures of monoethanolamine with N-methyldiethanolamine, monoethanolamine with 2-amino-2-methyl-1-propanol and monoethanolamine with 2-piperidine ethanol were measured from 30 to 80℃ with a differential sacnning calorimeter (DSC). The heat capacities of N-methyldiethanolamine, N-methyldiethanolamine + water, monoethanolamine + N-methyldiethanolamine, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol + water, and monoethanolamine + 2-amino-2-methyl-1-propanol were also studied. The estimated uncertainty of the measured heat capacities is ±2%. An excess molar heat capacity expression using the Redlich-Kister equation for the composition dependence is used to represent the measured CP of alkanolamine aqueous solutions. The overall average absolute percentage deviations for the calculation of the molar heat capacities are 0.12% and 0.29% for the binary and ternary systems, respectively. The heat capacities of aqueous mixtures of monoethanolamine with N-methyldiethanolamine, monoethanolamine with 2-amino-2-methyl-1-propanol and monoethanolamine with 2-piperidine ethanol presented in this study are, in general, of sufficient accuracy for most engineering-design calculations.
38
Wu-Yung, Wu, and 吳武忠. "Measurement of vapor-liquid equilibria : CO2/MEA/MDEA/H2O system." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/92882735893794478990.
Full textAbstract:
碩士中原大學
化學工程研究所
86
The equilibrium solubility of acid gas (CO2) in aqueous MEA（monoethanolamine)/MDEA（N-methyldiethanolamine）solutionshas been measured at temperatures40,60,80and100.The partialpressure of acid gas (CO2)is ranged from 1.0kPa to 200 kPa.The systems selected for this study are six blended aminessolutions consisting of 30wt% MEA,24wt% MEA+6wt% MDEA,18wt%MEA+12wt% MDEA, 12wt% MEA + 18wt% MDEA,6wt% MEA+24wt% MDEA,30wt% MDEA. The obtained apor-liquid equilibrium data have been represented by the correlation of Deshmukh and Mather(1981).The model reproduces reasonably the equilibrium par-tial pressure of CO2 or H2S above the solutions the systemstested. The results of this study can serve as a valuabledata base for effcient design of acid gas treating process,using blended amine as the absorption fluids.
39
Nittaya, Thanita. "Dynamic Modelling and Control of MEA." Thesis, 2014. http://hdl.handle.net/10012/8128.
Full textAbstract:
Greenhouse gas (GHG) emission control has been extensively studied over the past decade. One GHG mitigation alternative is post-combustion carbon dioxide (CO2) capture using chemical absorption, which is a promising alternative due to its proven technology and the relative ease to install on existing coal-fired power plants. Nevertheless, the implementation of commercial-scale CO2 capture plants faces several challenges, such as high energy consumption, commercial availability, and geological CO2 storage. Therefore, there is a great incentive to develop studies that provide insights needed to design and dynamically operate industrial-scale CO2 capture plants for coal-fired power plants.
This work presents a mechanistic dynamic model of a pilot plant of a post-combustion CO2 capture plant using the monoethanolamine (MEA) absorption processes. This model was implemented in gPROMS. The process insights gained from the sensitivity analysis, on six manipulated variables and six potential controlled variables, was used to determine promising control schemes for this pilot plant. This study then proposed three decentralized control structures. The first control scheme was designed based on the traditional-RGA (Relative Gain Array) analysis, whereas the other two control schemes were designed using heuristics. The performance evaluation of those control structures were conducted under eight scenarios, e.g. changes in flue gas composition, set point tracking, valve stiction, reboiler heat duty constraint, and flue gas flow rate. Under the condition where the reboiler temperature is to be controlled, a control scheme obtained from the heuristic showed faster response to achieve the process control objectives (90% CO2 capture rate and 95 mol% CO2 purity in the CO2 product stream) than the RGA-based control scheme.
Furthermore, this study describes a step-by-step method to scale-up an MEA absorption plant for CO2 capture from a 750 MW supercritical coal-fired power plants. This industrial-scale CO2 capture plant consists of three absorbers (11.8 m diameter, 34 m bed height) and two strippers (10.4 m diameter, 16 m bed height) to achieve 87% CO2 captured rate and 95% CO2 purity in the CO2 product stream. It was calculated that the reboiler heat duty of 4.1GJ is required to remove 1 tonne of CO2 at the base case condition (20 kmol/s of flue gas flow rate with 16.3 mol% of CO2). The mechanistic model of an industrial-scale CO2 capture plant including a proposed control structure was evaluated using different scenarios. The performance evaluation result revealed that this plant can accommodate a maximum flue gas flow rate of +22% from the nominal condition due to absorbers??? flooding constraints. Moreover, it is able to handle different disturbances and offers prompt responses (After a plant is disturbed by an external perturbation, control variables in that plant are able to return to their set points in timely fashion using the adjustment of manipulated variables.) without significant oscillating signal or offset. In addition, this study highlights that the poor wetting in the strippers can be avoided by the implementation of a process scheduling, which has not been presented in any publications.
Based on the above, the mechanistic models of CO2 absorption plants and proposed control structures provide insights regarding dynamic behaviour and controllability of these plants. In addition, the industrial-scale CO2 capture plant model can be used for future studies, i.e. integration of power plant and CO2 capture plant, feasibility of plant operation, and controllability improvement.
40
Liao, Chen-Hung, and 廖振宏. "Measurement of the Reaction Kinetics of CO2 with aqueous MEA/MDEA solutions." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56612318714650019245.
Full textAbstract:
碩士中原大學
化學工程研究所
89
The kinetics of the reaction between CO2 and MEA ( monoethanolamine ) and MDEA ( N-methyldiethanolamine ) were investigated at 30, 35, 40℃ by a wetted wall column. The concentrations studied were MEA (0.1-0.5 kmol‧m-3) / MDEA (0.1-0.5 kmol‧m-3). A Hybrid Kinetic Model has been used to describe the reaction of CO2 with MEA and MDEA. The solubility and diffusivity in aqueous solution blends MEA and MDEA were estimated by N2O analogy. For the experiment as result，we find that the Hybrid Kinetic Model can explain the reaction of CO2 with MEA and MDEA .
41
Neves, Sílvia Carina Leal das. "Mea culpa : depressão, masoquismo moral e religião." Master's thesis, 2010. http://hdl.handle.net/10451/1916.
Full textAbstract:
Tese de mestrado, Psicologia (Psicologia Clínica e da Saúde - Núcleo de Psicologia Clínica Dinâmica), Universidade de Lisboa, Faculdade de Psicologia, 2010Tomando em consideração a investigação que tem sido realizada no âmbito da relação entre a religião e a psicopatologia, propus-me a estudar qual a função da culpa, do mecanismo do masoquismo moral na religiosidade. O meu objectivo foi então apurar qual o papel da culpa na expressão deste tipo de comportamento e crença, procurando a possível influência de traços de personalidade associados à depressão e à culpa. Com esta finalidade, numa amostra de 105 indivíduos do sexo masculino e feminino, com idades entre os 19 e os 47 anos, aplicaram-se os seguintes instrumentos de medida: o Questionário de Experiências Depressivas [Q.E.D.] (Blatt, D’Afflitti et al., 1976; Blatt, D’Afflitti & Quinlan,1979), usando a adaptação para a população portuguesa de Rui Costa Campos (2000); o Test of Self-Conscious Affect [TOSCA] (Tangney,Wagner, Gramzow,1989) usando a tradução portuguesa para adultos de Geada (2000); e a Escala de Orientação Religiosa [Age-Universal I/E-Revised Scale] (Goursuch & McPherson,1989), usando a versão para estudo de Linares(2009). Esperava-se que existisse uma correlação positiva entre a religiosidade intrínseca e a culpa (hipótese 1), uma correlação positiva entre a religiosidade intrínseca e a personalidade depressiva de tipo introjectivo (hipótese 2), uma correlação positiva entre o auto-criticismo e a culpa (hipótese 3). Os resultados obtidos demostram que todas as hipóteses foram refutadas. São apontadas as limitações e outras possibilidades de investigação.
Taking in account the investigation carried through in the scope of religion and its relations with psychopathology, I have proposed myself to study the function of guilt, the mechanism of moral masochism in religioussness. My goal was to verify the importance of guilt in the expression of this kind of behavior and belief, searching the possible influence of personality traits associated with depression and guilt. For this purpose, a sample of 105 males and females aged 19 to 47 years, was tested by apllying the following scales: the Depressive Experiences Questionnaire [D.E.P.] (Blatt, D'afflitto et al . 1976; Blatt, D'afflitto & Quinlan, 1979), using the adaptation to Portuguese of Rui Costa Campos (2000), the Test of Self-Conscious Affect [TOSCA] (Tangney, Wagner, Gramzow, 1989) using the Portuguese translation for adults of Geada (2000), and the Religious Orientation Scale [Age-Universal I / E Scale-Revised] (Goursuch & McPherson, 1989), using the version for the study of Linares (2009). It was hoped that there was a positive correlation between intrinsic religiosity and guilt (hypothesis 1), a positive correlation between intrinsic religiosity and depressive personality (with an introjective dimension), a positive correlation between selfcriticism and guilt (hypothesis 3). The data shows that all hypothesis were rejected. The authors identify the limitations and further research possibilities.
42
Peng, Po-Hsuan, and 彭柏瑄. "Degradation mechanism study of Nafion MEA for PEMFCs." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/41675046288275622606.
Full textAbstract:
碩士元智大學
化學工程與材料科學學系
104
In this study, many related measurements were conducted before and after ageing test at 50°C and 40 % humidity to examine the change of characteristics of MEA components. The resulting electrodes, membranes and membrane electrode assemblies (MEAs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectrometer (XPS), and fourier transform infrared spectroscope (FTIR). FTIR analyses indicated that the chemical structure of Nafion does not change after ageing tests. TEM Images of Pt/C showed Pt nanoparticle coalescence after ageing test. The reduction of Pt amount on cathode side was observed from SEM results. Pt band formed inside the membrane were detected by XRD and TEM analyses, which is due to dissolved platinum from the cathode diffuse into the membrane and recrystallize by interacting with the crossover hydrogen. Based on these results, corrosion of the carbon support and Pt aggregation are the major reasons for MEA performance degradation.
43
Yu, Kun-Siou, and 余坤修. "Investigation of Properties in MEA-Contained Polymer-Liposome." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/45626970682325310892.
Full textAbstract:
碩士國立陽明大學
醫學工程研究所
102
Liposome was used as drug carriers in cancer therapy. It not only possesses good biocompability but also has ability to improve therapeutic efficiency and reduce the side effects. However, liposome still exhibits instablity in the blood circulation owing to serum protein adsorption on the surface. The superficial protein of the liposome is related to the preferential accumulation in liver or spleen, leading to rapid clearance from human body. Therefore, reducing the protein adsorption on the surface of liposome is a quite important issue. In this study, poly(ethylene glycol) (PEG), 2-methoxyethyl acrylate(MEA), and hydroxyethyl methacrylate(HEMA) were utilized to prepared the polymer-liposome to investigate the influence of the protein adsorption on the surface of liposomes as well as the feasibility for cancer therapy. In this study, different proportions of copolymer were synthesized and characterized by 1H-NMR, FT-IR and GPC. The polymer-liposomes were also prepared and their properties were further investigated. According to the results, MEA-contained polymer-liposomes (the molecular weight of the copolymer: 6000) showed high stability by analysis of DLS and qNano. Less drug leakage behaviors of MEA-contained polymer-liposomes were observed in presence of 4% bovine serum albumin (BSA). In vitro tests, the results of flow cytometry indicated that the MEA in polymer-liposomes could not prevent the polymer-liposomes from endocytosis into human colon cancer cells HCT116. The endocytosis pathway of MEA-contained polymer- liposomes is even the same as the other polymer- liposomes. MEA-contained polymer-liposomes could evade from serum protein adsorption, while they exhibited low cytotoxicity and could be uptaken by cancer cells. MEA-contained polymer-liposomes were worth being developed as a drug carrier for anti-cancer therapy.
44
Li, Frwu Yuan, and 黎福源. "Measurement and Prediction of solubility of CO2 and H2S in aqueous MEA/MDEA solutions." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/31816469188760600322.
Full textAbstract:
碩士中原大學
化學工程研究所
81
Alkanolamines are extensively used as absorbents for removal of acid gas impurties such as H2S, CO2. The conventionally used alkanolamines are MEA(monoethanolamine), DEA(diethanolamine), TEA(triethanolamine), MDEA(methyl-diethanolamine) and sterically hindered amines such as AMP(2-amino-2-methyl-1- propanol) and PE(2-piperidine ethanol). In industrial gas treating processes, single-amine aqueous solutions are frequently used as absorbents. Recently, the use of blended amines solutions was proposed for removal of acidic gases. It is the purpose to retain the advantages of each amine such as high absorption rates and high absorption capacities and to develop the more effective absorbents.Because the equilibrium solubilities of acid gases in alkanolamines are important for the rational design of absorbers and strippers. It is the purpose of this reseach to study the vapor liquid eqilibrium behaviour of H2S and CO2 in blended amines MEA/PE/H2O system. The solubilities of H2S and CO2 in aqueous mixtures of MEA and PE have been measured at 40, 60, 80, and 100°C. The blended amines studied are 30 wt%MEA , 24 wt%MEA + 6 wt%PE, 12 wt%MEA + 18 wt%PE, and 30 wt%PE. The partial pressures are from 1.0 kPa to 1500kPa and from 0.1kPa to 200kPa for H2S and CO2, respectively. A semi-empirical thermodynamic model has also been developed to correlate the experimental data.
45
Ricardo, José Eduardo Firmino. "Domus Mea est Orbis Meus: Campos Monteiro (1876-1933)." Master's thesis, 2008. http://hdl.handle.net/10348/184.
Full textAbstract:
Dissertação de Mestrado em Ensino da Língua e da Literatura PortuguesasAbílio Adriano Campos Monteiro foi, no seu tempo, um dos escritores mais populares e mais lidos. Saúde e Fraternidade, por exemplo, um relato satírico e visionário da história dos acontecimentos políticos em Portugal, desde Agosto de 1924 a Novembro de 1926, alcançou, segundo Aquilino Ribeiro, o maior êxito de livraria no primeiro quartel do século (venderam-se 40 mil exemplares no espaço de seis meses). Para além de poeta, dramaturgo, e romancista, publicou ainda Os Lusíadas Anotados e Parafraseados que foi, durante muito tempo, a edição de Camões oficialmente adoptada nas escolas portuguesas. Fundou revistas e colaborou em diversos jornais. Parlamentar desiludido e fugaz, médico de profissão, o homem que nasceu em Torre de Moncorvo, em 10 de Abril de 1876, foi, sobretudo, um escritor. Mas foi também um cidadão empenhado em causas que acreditava, mesmo quando as mudanças sociais corriam do lado oposto ao que sempre permaneceu. Foi, portanto, como escritor e jornalista que construiu o seu percurso nas letras portuguesas, percurso esse alicerçado num mundo que era, afinal, a sua Pátria: Domus Mea est Orbis Meus.
Abílio Adriano Campos Monteiro was, in his time, one of the most popular and most read writers. Saúde e Fraternidade, a satirical and visionary report about Portugal’s political history (between August 1924 to 1926), was, according to Aquilino Ribeiro, the most successful bookshop outcome in the first quarter of the century (forty million copies were sold in six months). Apart from being a poet, playwright and novelist, he wrote Os Lusíadas Anotados e Parafraseados, which was adopted for a long time as the official Lusíadas edition in schools. He also founded magazines and collaborated with several newspapers. An unhappy and short lived parliamentary, doctor of profession, the man who was born in Torre de Moncorvo on 10th April 1876, was above all a writer. Campos Monteiro was also a dedicated citizen to causes he believed in, even facing adverse social changes. It was therefore as journalist and writer, that he made his way through the Portuguese Literature, an edified journey in a world, which was after all, his country: Domus Mea est Orbis Meus.
46
Sá, Ana Isabel Salvado de. "Traduzir Mea Culpa ao ritmo de Louis-Ferdinand Céline." Master's thesis, 2014. http://hdl.handle.net/10316/27671.
Full textAbstract:
Dissertação de Mestrado em Tradução apresentada à Faculdade de Letras da Universidade de Coimbra.Na origem do presente projecto de tradução está o reconhecimento de que a tradução literária convoca um universo plural epistemológico, o qual, se é certo que advém de uma forma de mediação riquíssima entre duas línguas e duas culturas, também ganha substância se contemplar uma reflexão sobre a linguagem humana. Referimo-nos, por outras palavras, à relação dinâmica e complementar entre língua e linguagem que, quando presente num processo cognitivo tão peculiar como o do tradutor literário, culmina quase sempre numa recompensa intelectual. De igual modo, num sentido mais prático, é uma aliança que permite identificar uma tipologia de problemas de tradução diferente da convencional, ou seja, por se libertar um pouco da metodologia estruturalista e por redimensionar as noções tradicionais da linguística, contempla outro tipo de questões pertinentes como a presença de sociolectos, ou a singularidade discursiva de uma voz que nos fala através do texto literário. Partindo, assim, de uma fórmula heurística mais geral, o nosso quadro teórico orienta- -se por várias leituras dialogísticas que, do discurso hermenêutico de Schleirmacher (2004), George Steiner (1998), ou Ricoeur (1984), à teoria crítica do ritmo de Henri Meschonnic (1982 e 2002), se cristaliza num quadro de análise textual estratificado. Proposto por João Barrento (2002), este “escavar” dos aspectos fonológico, lexical, semântico, morfossintáctico, semântico, cultural e pragmático revela-se eficaz por atender, em primeiro lugar, às características do texto original e, posteriormente, aos recortes de análise do texto traduzido. Neste sentido, ao entrecruzar “subjectividade” com “objectividade”, julgamos poder responder ao desafio teórico e prático que implica traduzir um autor tão peculiar quanto Louis-Ferdinand Céline e, em particular, o seu panfleto anti-comunista de 1937 intitulado Mea Culpa1 . Se, de facto, ao fazermos referência à tradução tanto do autor quanto do texto, justificamos, por um lado, a pertinência da já mencionada relação entre língua e linguagem subjacente a este trabalho, por outro lado também clarificamos a razão principal que nos levou a escolher este texto enquanto objecto de tradução: o tributo a um dos nossos autores de eleição. A par desta, o relevo que a tradução assume para a consolidação dos textos foi outra razão que contribuiu para a nossa escolha, pois, no âmbito deste trabalho, é-nos permitida a possibilidade de oferecer ao mundo académico português, ou a outros possíveis interessados, uma fonte primordial de conhecimento histórico, nomeadamente quando se trata de um texto polémico que causa um certo desconforto às editoras. Na verdade, o facto de Mea Culpa (1937) já ter sido traduzido há aproximadamente quinze anos, por Manuel João Gomes, mas ter-se cingido somente a uma primeira edição, também contribuiu para a nossa vontade de relançar um documento ímpar sobre o Comunismo, o qual, além de contemplar um sentido forte dos problemas políticos, ganha uma força suplementar devido às marcas de testemunho pessoal. Outra das razões coaduna-se com o questionar da aplicação de metodologias herdeiras do Estruturalismo quando traduzimos um escritor que é, ele mesmo, um heterodoxo e um anti- -académico levando, portanto, a ponderar a capacidade de resposta de um quadro teórico alternativo e satisfatório. Por conseguinte, optámos por testar a viabilidade de um método que, privilegiando o ritmo discursivo enquanto princípio semântico, aponta não só para a tentativa de manutenção de uma prosódia pessoal no texto traduzido, como também para inverter a ideia da invisibilidade do tradutor, pois é inevitável que a sua voz não se (con)funda com a do autor ao longo de todo o processo de descodificação que, iniciado com a leitura do texto original, se reflectirá, portanto, no texto traduzido. Neste sentido, o presente projecto de tradução encontra-se dividido em cinco partes, as quais também espelham as etapas por que fomos passando: numa primeira secção apresentamos a biografia de Louis-Ferdinand Céline, essencial para lançar as bases hermenêuticas subjacentes ao nosso processo de tradução e para dar a conhecer ao leitor as características mais gerais que perfazem a singularidade do autor; na segunda, ainda de carácter introdutório, propomos uma reflexão sobre a orgânica específica do panfleto, assim como os seus principais aspectos temáticos; já num terceiro momento, ao analisarmos sobretudo os estratos que compõem o texto original, enveredamos pelo fio condutor relativo ao nosso enquadramento teórico-metodológico culminando, assim, num quarto momento, o qual consiste na tradução integral de Mea Culpa (1937); na quinta parte, retomamos o modelo dos diferentes estratos proposto por João Barrento (2002), para, então, identificarmos a tipologia de problemas encontrados durante a tradução e problematizarmos os vários recortes de análise, bem como as opções tomadas. Finalmente, completamos o trabalho com as últimas considerações tecidas aos métodos aplicados e aos resultados obtidos, esperando que os mesmos possam contribuir para a sempre inesgotável pesquisa efectuada pelos Estudos de Tradução. De referir ainda que o presente projecto de tradução não se encontra escrito ao abrigo do Novo Acordo Ortográfico da Língua Portuguesa.
47
Tsai, Pei An, and 蔡培安. "Generation of Oxygen by using Membrane Electrode Assembly (MEA)." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/83q7cp.
Full textAbstract:
碩士長庚大學
化工與材料工程學系
105
Oxygen (O2) gas has widely applications. There are several methods to produce O2 in industry. For instance, membrane separation, water electrolysis…etc. In this study, water electrolysis is used to produce O2. The working electrode is self-made by using carbon supported metal clusters combined with proton conducting membrane(Nafion). Through the membrane electrode in fuel cells and fabricated gas diffusion electrode as working electrode, can produce larger current with oxygen generation. We use different ratios of catalysts to make fabricated gas diffusion electrode and test them after they build up to membrane electrode by using cyclic voltammetry for their feasibility. By using constant-current and constant-voltage methods to make linear analysis, we can calculate the amount of O2 produced with specific methods. Finally, according to amount of O2 for human breathing, we evaluate the amount O2 produced by experiments whether it is sufficient to be used.
48
Shih, Liang Sing, and 施良興. "Study and Analysis on coating of MEA for PEMFC." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/fa3cwm.
Full textAbstract:
碩士國立虎尾科技大學
材料科學與綠色能源工程研究所
96
This thesis is to develop procedures on coating of membrane electrode assembly (MEA), the heart of the Proton Exchange Membrane Fuel Cell. The operating factors affected the performance of fuel cells, such as the method of the coating, coating positions, operating temperature, are investigated. The coating procedures on the Nafion membrane is the hardest task. The contact conditions between the catalyst layer and the Nafion membrane are improved to obtain the close attachment of them. In order to overcome the undesirable crease and expansion encountered with coating of Nafion membrane, a self-designed clamp is adopted to fix Nafion membrane tightly. The experiments are conducted using three different methods, i.e. spraying, painting, and scraper, applied to two types of membrane, i.e. Nafion and Carbon-Cloth/Nafion. The spraying method gives the best performance compared with the painting and the scraper method, since it achieves outstanding uniformity of spraying and does not generate cracking phenomenon on the catalyst layer. Furthermore, the spraying method also gives the best performance of fuel cell on Carbon-Cloth/Nafion membrane. At low current density, the performance difference between Nafion and Carbon-Cloth/Nafion membrane is small. However, at high current density comparison, the performance of the latter significantly improves. Therefore, coating on Carbon-Cloth/Nafion gives a desirable effect under high loading. The operating temperature of cell is increased to promote its performance because higher temperature will make the catalyst reaction more active. The experimental results show that the best performance is attained ,under an operating temperature of 50℃ in the cell, using the spraying method on Carbon-Cloth/Nafion membrane under an optimal conditions of 0.203 V , the current density of 2498.6 mA/cm2, and the power density of 502 mW/cm2. The method of the coating and coating positions in this paper is different from what has been done in the past. It is found that some methods applied here can improve the MEA performance. It can be concluded that optimizing the coating procedure of MEA will reduce material consumption and human error, and have favorable improvement on performance as well as cost reduction.
49
Yi-Hao, Pai. "Process Optimization and Characteristics of Nano MEA Materials for PEMFC." 2007. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0005-0904200710484000.
Full text
50
Wu, Hung-Yu, and 吳紘宇. "Photocatalytic Reduction of CO2 Using Porous Photocatalysts in MEA Solution." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/32pxgk.
Full textAbstract:
博士國立交通大學
環境工程系所
104
This study intends to propose and study a technology which combines CO2 capture and utilization (CCU) by using ethanolamine (MEA) as the CO2 absorbent and reductant in the solution. To explore the feasibility of ethanolamine as the CO2 absorbent and photocatalytic reducing agent, the CO2 reduction efficiency was compared with commonly used reducing agents in the literature. Photocatalysts with high specific surface area were then prepared and tested under different operating parameters including the light wavelenths from UV to visible light. The CO2 reduction efficiency, photo-reduction quantum efficiency (PQE), and the possible reaction mechanisms were proposed in this study. The innovative results of this study include the prove of MEA to be the best absorbent/reductant as compared to the NaOH and H2O solution. Therefore, MEA solution is employed in this study for studying the photocatalytic reduction of CO2 to form valuable energy source of methane (CH4) and the total combustible organic compounds (TCOCs) at different light spectra of UV light sources (254, 365 nm) and solar concentrator as well. The results showed that methane yields of the modified photocatalysts of Ti-MCM-41(X) and Mo-TNTs were better than the pure TiO2 when irradiated under both UV and visible light sources. The 8 hours test results showed that the best metal photocatalyst at 254nm was Ti-MCM-41(50), which has the methane yield of 62.42μmol/g and the carbon monoxide yield of 27.65μmol/g under 32μW/cm2 light intensity. And the best photocatalyst was Mo-T-500 under 365nm UV light, which material was prepared under pH=3. Its methane production rate was 0.52μmol/g with the light intensity of 63μW/cm2. And the other products of carbon monoxide and TCOCs yields were 10.41μmol/g and 13.53μmol/g, respectively. In addition, the Mo-T-500 was also tested for its long-term (24hrs) stability under visible light condition (fluorescent lamp, 840nm, 8W). The product yield of TCOCs was up to 10.29 µmol/g after 24 hrs. The long-term stability test for photocatalytic reduction of CO2 under visible light proved the feasibility of Mo-TNTs to work in MEA solution. From the analysis of chemical and physical properties of Mo-TNTs, it revealed that the structure of Mo-TNTs was changed with the increase of calcination temperature. For Mo-TNTs calcined at 500 °C, the partial corruption of titanate nanotubes into anatase particles caused the reduction of Mo species from Mo6+ to Mo5+ and produced oxygen vacancies, which resulted in the highest CO2 reduction ability. It was found that the molybdenum structure and oxygen vacancies could be the key factors controlling the photocatalytic reduction efficiency of CO2. Possible structure transformation of Mo-TNTs at different calcination temperatures was inferred. And reaction mechanism for photocatalytic CO2 reduction with oxygen vacancy sites of Mo-TNTs was proposed.