Dissertationen zum Thema „CO₂ separation“
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Xie, Xiaofeng. „CO₂-expanded liquids for separation and reaction“. Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/10077.
Der volle Inhalt der QuelleShen, Dawei. „Co-channel digital signal separation : application and practice“. Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/42408.
Der volle Inhalt der QuelleIncludes bibliographical references (leaves 84-86).
This thesis studies the theory and application of co-channel digital signal separation techniques. We set up a test-bed with the GNU Software Defined Radio (SDR) platform where we implement and experiment with single-antenna signal separation algorithms. We mainly investigate linearly-modulated digital signals. To do this, we design a multiple RFID card reader capable of decoding multiple commodity ID cards simultaneously. These passive RFID cards transmit DBPSK waveforms once activated. A signal separation function at the receiver delivers great convenience to the users without increasing the complexity and cost of the cards. Second, we derive the optimal criteria for deciding the start of an RFID frame. We show that the commonly utilized correlation rule is suboptimal and that a correction term needs to be considered to achieve the best detection performance. Several rules for frame synchronization are proposed and analyzed numerically using Monte Carlo simulation. These signal separation techniques present an opportunity to improve the capacity of wireless systems and combat interference. This thesis documents design issues in the physical and application layers, thereby demonstrating the great flexibility and strength of the GNU SDR system.
by Dawei Shen.
S.M.
Jegede, Oluwatoyin Enitan. „Metastable liquid phase separation in Co-Cu alloys“. Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/19808/.
Der volle Inhalt der QuelleWoo, Grace R. „Demonstration and evaluation of co-channel DBPSK source separation“. Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42170.
Der volle Inhalt der QuelleIncludes bibliographical references (leaves 51-53).
This thesis presents a Differential Binary Phase Shift Key (DBPSK) source separation system implemented with the GNU Software Defined Radio (SDR) platform and interfaced with the existing MIT community Radio Frequency Identification (RFID) system. Source separation, well studied in the theoretical signal processing setting, presents an opportunity to achieve higher throughput in a practical SDR deployment. While much research has centered around the design of complex multi-input-multi-output (MIMO) and code division multiple access (CDMA) systems, single antenna source separation presents a simple alternative that is suitable in settings such as RFID where sources are naturally synchronized. Motivated by the analysis of physical channel properties with GNU SDR, this thesis documents the complete design process from the physical layer to the application layer and presents a realization of a co-channel DBPSK source separating technique. The result is an intelligent RFID source-separating reader that is capable of decoding multiple "dumb" cards.
by Grace R. Woo.
S.M.
Kim, Sangil. „Modified ordered mesoporous silica membranes for CO₂ -N₂ separation“. Cincinnati, Ohio : University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1070484926.
Der volle Inhalt der QuelleCorcoran, Edward W., Ronald R. Chance, Harry W. Deckman, Gregory J. DeMartin, Sebastián C. Reyes, C. J. Yoon und Trevor E. Clark. „Molecular transport in inorganic membranes: CO 2 /CH 4 separation“. Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194810.
Der volle Inhalt der QuelleCorcoran, Edward W., Ronald R. Chance, Harry W. Deckman, Gregory J. DeMartin, Sebastián C. Reyes, C. J. Yoon und Trevor E. Clark. „Molecular transport in inorganic membranes: CO 2 /CH 4 separation“. Diffusion fundamentals 3 (2005) 18, S. 1, 2005. https://ul.qucosa.de/id/qucosa%3A14307.
Der volle Inhalt der QuelleAbbassi, Maria. „Selective CO Adsorption Separation from CO2 via Cu-modified Adsorbents“. Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42151.
Der volle Inhalt der QuelleCowan, Oliver. „Co-occurrence and phenological niche separation in rodent pollinated Proteaceae“. Bachelor's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/24855.
Der volle Inhalt der QuelleVaughn, Justin. „Development and evaluation of aromatic polyamide-imide membranes for H₂S and CO₂ separations from natural gas“. Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47576.
Der volle Inhalt der QuelleNzama, Nosipho Mercy. „Adsorptive separation of Ce Co Ru Sb and Sr ions using inorganic ion exchangers“. Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/79295.
Der volle Inhalt der QuelleDissertation (MSc)--University of Pretoria, 2019.
Chemical Technology
MSc
Unrestricted
Zhang, Naiyuan. „Hydrogen Isotope Separation in Metal-Organic Frameworks“. Oberlin College Honors Theses / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1532013686771173.
Der volle Inhalt der QuelleKim, Danny Jinsoo. „Effects of polymerization conditions and imidization methods on performance of crosslinkable polymer membrane for CO₂/CH₄ separation“. Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/48938.
Der volle Inhalt der QuelleWilson, Graeme Barnetson. „Fathers as co-parents : how non-resident fathers construe family situations after divorce or separation“. Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/1131/.
Der volle Inhalt der QuelleKane, Dellwyn. „Hydrograph separation using end member mixing models in the Oona Water river catchment, Co Tyrone“. Thesis, University of Ulster, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529518.
Der volle Inhalt der QuelleKIM, SANGIL. „MODIFIED ORDERED MESOPOROUS SILICA MEMBRANES FOR CO 2 -N 2 SEPARATION“. University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1070484926.
Der volle Inhalt der QuellePopp, Nadine [Verfasser], und Jürgen [Akademischer Betreuer] Senker. „Poröse organische Netzwerke zur selektiven CO₂ Speicherung und Separation von Gasgemischen / Nadine Popp ; Betreuer: Jürgen Senker“. Bayreuth : Universität Bayreuth, 2017. http://d-nb.info/1130243249/34.
Der volle Inhalt der QuelleBubier, Jennifer L. „Co-occurrence of Oppositional Defiant Disorder with Generalized and Separation Anxiety Disorders Among Inner-city Children“. Diss., Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/48936.
Der volle Inhalt der QuellePh.D.
There is a paucity of research that has examined co-occurring oppositional defiant disorder and generalized anxiety disorder (ODD+GAD) symptoms and oppositional defiant disorder and separation anxiety disorder (ODD+SAD) symptoms among children. To address this gap, I investigated multiple explanations for the co-occurrence of ODD+GAD and ODD+SAD. Specifically, I investigated whether (a) GAD symptoms prospectively predicted ODD symptoms and SAD symptoms prospectively predicted ODD symptoms (Explanation 1), (b) ODD symptoms prospectively predicted GAD symptoms and ODD symptoms prospectively predicted SAD symptoms (Explanation 2), and (c) shared risk processes accounted for the co-occurrence of ODD+GAD and ODD+SAD (Explanation 3). Participants were an ethnic minority, inner-city sample of first through fourth grade children (N = 88, 51% male) and their primary caregivers. I used data collected at the baseline and 1-year follow-up assessments of the Child Health and Behavior Study, a longitudinal survey of families residing in North Philadelphia. Findings provided support for Explanation 2 and Explanation 3 in the development of co-occurring ODD+GAD symptoms and support for Explanation 3 in the development of co-occurring ODD+SAD symptoms. This study contributes to the extant literature by providing the first empirical examination of these multiple explanations in an ethnic minority, inner city sample of children.
Temple University--Theses
Foster, Paul J. „Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution“. Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1789.pdf.
Der volle Inhalt der QuelleSahin, Mustafa. „Baseband receiver algorithms for 4G co-channel femtocells“. [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003283.
Der volle Inhalt der QuelleBrunson, Kennard. „POLYURETHANE-BASED POLYMER SURFACE MODIFIERS WITH ALKYL AMMONIUM CO-POLYOXETANE SOFT BLOCKS: REACTION ENGINEERING, SURFACE MORPHOLOGY AND ANTIMICROBIAL BEHAVIOR“. VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2258.
Der volle Inhalt der QuelleArmstrong, Shannon Renee. „Novel Applications of Co-Extruded Multilayer Polymeric Films“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1370531152.
Der volle Inhalt der QuelleSalim, Witopo. „CO2-selective Membranes for Fuel Cell H2 Purification and Flue Gas CO2 Capture: From Lab Scale to Field Testing“. The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514889154359659.
Der volle Inhalt der QuelleWilson, Sean M. W. „Adsorption Separation of CO2 from CO in Syngas: Improving the Conversion of the Reverse Water Gas Shift Reaction“. Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33169.
Der volle Inhalt der QuelleGupta, Himanshu. „NOx reduction by Carbonaceous Materials and CO₂ separation using regenerative metal oxides from fossil fuel based flue gas /“. The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486399160107212.
Der volle Inhalt der QuelleKeller, Laura [Verfasser], Matthias [Akademischer Betreuer] Wessling und Ryan P. [Akademischer Betreuer] Lively. „Microtubes made of carbon nanotube hybrid materials for CO$_2}$ separation / Laura Keller ; Matthias Wessling, Ryan P. Lively“. Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1218787910/34.
Der volle Inhalt der QuelleAnand, K. „Methods for Blind Separation of Co-Channel BPSK Signals Arriving at an Antenna Array and Their Performance Analysis“. Thesis, Indian Institute of Science, 1995. https://etd.iisc.ac.in/handle/2005/123.
Der volle Inhalt der QuelleAnand, K. „Methods for Blind Separation of Co-Channel BPSK Signals Arriving at an Antenna Array and Their Performance Analysis“. Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/123.
Der volle Inhalt der QuelleTarun, Cynthia. „Techno-Economic Study of CO2 Capture from Natural Gas Based Hydrogen Plants“. Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2837.
Der volle Inhalt der QuelleIn the current H2 plants, CO2 emissions originate from two sources, the combustion flue gases from the steam reformer furnace and the off-gas from the process (steam reforming and water-gas shift) reactions. The objective of this study is to develop a process that captures CO2 at minimum energy penalty in typical H2 plants.
The approach is to look at the best operating conditions when considering the H2 and steam production, CO2 production and external fuel requirements. The simulation in this study incorporates the kinetics of the steam methane reforming (SMR) and the water gas shift (WGS) reactions. It also includes the integration of CO2 capture technologies to typical H2 plants using pressure swing adsorption (PSA) to purify the H2 product. These typical H2 plants are the world standard of producing H2 and are then considered as the base case for this study. The base case is modified to account for the implementation of CO2 capture technologies. Two capture schemes are tested in this study. The first process scheme is the integration of a monoethanolamine (MEA) CO2 scrubbing process. The other scheme is the introduction of a cardo polyimide hollow fibre membrane capture process. Both schemes are designed to capture 80% of the CO2 from the H2 process at a purity of 98%.
The simulation results show that the H2 plant with the integration of CO2 capture has to be operated at the lowest steam to carbon (S/C) ratio, highest inlet temperature of the SMR and lowest inlet temperatures for the WGS converters to attain lowest energy penalty. H2 plant with membrane separation technology requires higher electricity requirement. However, it produces better quality of steam than the H2 plant with MEA-CO2 capture process which is used to supply the electricity requirement of the process. Fuel (highvale coal) is burned to supply the additional electricity requirement. The membrane based H2 plant requires higher additional electricity requirement for most of the operating conditions tested. However, it requires comparable energy penalty than the H2 plant with MEA-CO2 capture process when operated at the lowest energy operating conditions at 80% CO2 recovery.
This thesis also investigates the sensitivity of the energy penalty as function of the percent CO2 recovery. The break-even point is determined at a certain amount of CO2 recovery where the amount of energy produced is equal to the amount of energy required. This point, where no additional energy is required, is approximately 73% CO2 recovery for the MEA based capture plant and 57% CO2 recovery for the membrane based capture plant.
The amount of CO2 emissions at various CO2 recoveries using the best operating conditions is also presented. The results show that MEA plant has comparable CO2 emissions to that of the membrane plant at 80% CO2 recovery. MEA plant is more attractive than membrane plant at lower CO2 recoveries.
Maurer, Ronald W. „Competitive Adsorption of Poly(1-vinylpyrrolidone-co-styrene) and Kymene onto Wood Fibers: the Improved Effect of Sequential Adsorption“. Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14075.
Der volle Inhalt der QuelleLandaverde, Alvarado Carlos Jose. „Sorption, Transport and Gas Separation Properties of Zn-Based Metal Organic Frameworks (MOFs) and their Application in CO₂ Capture“. Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/73214.
Der volle Inhalt der QuellePh. D.
Abdollahi, Farhang. „Gas Separation by Adsorption in Order to Increase CO2 Conversion to CO via Reverse Water Gas Shift (RWGS) Reaction“. Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23993.
Der volle Inhalt der QuelleVinnakota, Keerthi. „Chemical Recycling of Poly (Ethylene Terephthalate) and its Co-polyesters with 2, 5-Furandicarboxylic Acid using Alkaline Hydrolysis“. University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1535106967389994.
Der volle Inhalt der QuelleGhafouri-Bakhsh, Shakour. „Morphological studies of polymer blends by scanning tunneling microscopy, phase separation in poly(methyl methacrylate)/poly(styrene- co-methylmethacrylate) systems“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1994. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ51530.pdf.
Der volle Inhalt der QuelleJung, Kyung Sook. „CO2 Separation and Regeneration Study From Power Plant Flue Gases With Reclaimed Mg(OH)2“. University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1122333773.
Der volle Inhalt der QuelleZago, Gustavo Pereira. „Estudo da co-cristalização em sistema ternário NaCI-CaSO4-H2O para dessalinização de água“. Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-15012018-132007/.
Der volle Inhalt der QuelleThe accelerated growth of the world population and the consequent increase in the production of consumer goods, has driven to a crisis in the availability of natural resources, especially water. Due to the scarcity of water resources, industrial and domestic wastewater treatment processes that aim the Zero Liquid Discharge (ZLD) have been increasingly studied. Nowadays, several processes have been used for this purpose. However, in all of them, there is still the generation of a brine composed of a concentrated salt solution, concomitantly with the recovered water, whose composition is normally constituted by different types of inorganic salts. One way to achieve the ZLD is through the implementation of an additional separation process, for which the evaporative crystallization is considered technically viable for this purpose. The use of this process is limited to the control of the morphological characteristics of the particles obtained, since this influences directly the separation effectiveness of the downstream processes to crystallization (filtration, centrifugation). Besides, industrial effluents are complex solutions and its crystallization involves the presence of more than one salt in solution (cocrystallization). This process is still not well investigated on scientific literature, thus, the determination of process conditions aiming to control the characteristics of these particles is not trivial. In this work, the effect of the evaporation rate and the presence of seeds on the morphology, composition, size and habit of sodium chloride and calcium sulfate particles obtained by batch evaporative co-crystallization were studied. The results were used to determine the operating parameters for the cocrystallization in order to obtain particles with high average size and narrow dispersion of sizes. High evaporation rates favored the obtaining of agglomerated particles. The presence of calcium sulfate in solution resulted in larger particles, less polydisperse and with less degree of agglomeration. Such result was considered positive, since, these characteristics are desirable for the separation of the crystals from the solution. Seeds of hemihydrate inhibited the agglomeration of the NaCl crystals. The increase in seed load of hemihydrate culminated in obtaining less agglomerated particles, but there was an increase in particle size distributions. In the experiments in which seeds of both salts were used, the same effect in the agglomeration was observed. In all experiments with seeds of hemihydrate, agglomeration of this salt with NaCl was observed, which was intensified with increasing evaporation rate and increasing seed amount. It was identified the possibility of recovery of both salts and, for certain conditions, obtaining more than 90% of NaCl with up to 99.50% purity.
Wang, Di. „Ιnnοvative cοmpοsite pοlymer materials fοr CΟ2 separatiοn“. Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMIR09.
Der volle Inhalt der QuelleCurrently, the emission of CO₂, which is the primary contributor to global warming, is increasing at an alarming rate. Consequently, there is a growing global need for cutting-edge technologies that can effectively separate and capture CO₂. In the present work, a series of PSF/IL and PES/IL composite membranes for CO₂ separation were investigated. Six ILs ([Meim][TFSO₃], [Vim][TFSO₃], [Meim][Tf₂N], [Vim][Tf₂N], Li(DOBA)[Tf₂N] and Li(HDA)[Tf₂N]) were synthesized successfully and characterized by FT-IR, 1H NMR, TGA and DSC. Composite membranes with different IL loadings were fabricated by solution casting method and exhaustively studied by FT-IR, TGA, DSC, SEM, F-mapping, surface energy, tensile tests, and gas permeation (CO₂, N₂ and O₂). Under 25°C and 4 bar, PES/10[Vim][Tf₂N] membrane showed a CO₂ permeability of 1.92 Barrer with improved CO₂/N₂ and CO₂/O₂ selectivities of 20.4 and 6.1, respectively
Vogel, Jörn-Oliver. „Co-deposited films of rod-like conjugated molecules“. Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15978.
Der volle Inhalt der QuelleThis thesis is centered on studies of phase separation and mixing in co-deposited thin films of rod-like conjugated molecules. The main focus is to determine which molecular properties lead to phase separation and/or mixing of two materials. To address this question I used five materials, of importance in the context of “organic electronics”: pentacene (PEN), quaterthiophene (4T), sexithiophene (6T), p-sexiphenylene (6P), alpha,omega-dihexylsexithiophene (DH6T). With these it was possible to form material pairs which differ in the parameters: energy levels, length of the conjugated core, and alkyl-end-chain-substitution. All films were deposited by organic molecular beam deposition onto the chemically inert substrates silicon oxide and Mylar, a polyethylene terephthalate (PET) foil. The material pairs were deposited simultaneously from two thermal sublima-tion sources. The mixing ratio was controlled by the individual deposition rates, which were measured online by a microbalance. The total deposition rate was 0.5 nm/min, and the film thicknesses ranged from 4 nm to 40 nm. Phase separation is observed for material pairs with dissimilar conjugated core sizes, i.e. [4T/6T]. Noteworthy, the co-deposition of material pairs with similarly sized conju-gated cores [4T/PEN] and [6T/6P] lead to well ordered layered structures. The mole-cules show mixing within layers on a molecular scale and the long molecular axis is ori-ented almost perpendicular to the substrate surface. Material pairs with similarly sized conjugated core and alkyl-end-chain-substitution [6T/DH6T] and [6P/DH6T] show also growth in mixed layered structures. An especially appealing fact is that the interlayer distance increases proportional to the DH6T content in the film. This can be explained with a phase separation into an aromatic and an alkyl domain vertically to the substrate surface. A decrease of the DH6T content in the film leads to a less dense packing in the alkyl domain. This leads, due to the flexibility of the alkyl chains, to a decrease of the overall interlayer distance. The low surface corrugation and the interconnected islands render the material pair [6T/DH6T] well suitable for the use as active layer in organic field effect transistors. It is shown that it is possible to tune the charge carrier density in the channel by changing the ratio between 6T and DH6T. This effect enables switching the transistor from en-hancement to depletion mode, while maintaining a high charge carrier mobility. This is comparable to p-type doping of inorganic semiconductors.
Wieczorek, Jens [Verfasser], und Uwe [Akademischer Betreuer] Bovensiepen. „Separation von laserinduzierten- ultraschnellen Transporteffekten und Spin-Flip-Streuung in Co/Cu(001) - Eine schichtdickenabhängige Magnetisierungsprofilanalyse mittels magnetooptischen Methoden / Jens Wieczorek. Betreuer: Uwe Bovensiepen“. Duisburg, 2015. http://d-nb.info/1079793526/34.
Der volle Inhalt der QuelleHuang, Jin. „CO2(H2S) membrane separations and WGS membrane reactor modeling for fuel cells“. Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1166640509.
Der volle Inhalt der QuelleTzou, Nicholas. „Low-cost sub-Nyquist sampling hardware and algorithm co-design for wideband and high-speed signal characterization and measurement“. Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51876.
Der volle Inhalt der QuelleLima, Juliana Aristeia de. „Comportamento de fases de soluções binarias e ternarias de poli(etileno-co-alcool vinilico), poli(metacrilato de metila) e dimetilformamida“. [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248789.
Der volle Inhalt der QuelleTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Neste trabalho foram estudadas blendas de poli(etileno-co-álcool vinílico) (EVOH), um copolímero semicristalino que combina segmentos hidrofílicos e hidrofóbicos e poli(metacrilato de metila) (PMMA), um polímero amorfo e hidrofílico. As blendas de EVOH, com teor de etileno variando de 27 a 44 mol %, e PMMA foram preparadas por casting a partir de soluções em DMF, e por mistura mecânica em um mini-misturador, objetivando: i) avaliar o comportamento de fases e a morfologia das blendas, EVOH/PMMA, em função da composição das misturas, do teor de etileno nos copolímeros de EVOH e do método de preparação; ii) obter os diagramas de fases das soluções binárias, EVOH/DMF, e ternárias, EVOH/PMMA/DMF, através do processo de separação de fases induzido termicamente (TIPS). O comportamento de fases das blendas, EVOH/PMMA, foi estudado através de Calorimetria Diferencial de Varredura (DSC) e Análise Dinâmico-Mecânica (DMA). A morfologia das blendas foi investigada por Microscopia Eletrônica de Varredura (SEM). As blendas independentemente do modo de preparação e da composição são imiscíveis. Como conseqüência desta imiscibilidade, as temperaturas de fusão (Tf) e cristalização (Tc) não são afetadas pela presença de PMMA. A morfologia das blendas varia com a composição e método de preparação. As blendas obtidas pelo método mecânico são compactas, apresentando morfologia de fase dispersa em uma matriz, com inversão de fases em aproximadamente 50 % em massa de cada componente. As soluções binárias, EVOH/DMF, e ternárias, EVOH/PMMA/DMF, foram submetidas a ensaios para a determinação das temperaturas de turvamento (Tturv) por microscopia ótica, e de cristalização dinâmica (Tcd), por DSC. As soluções binárias apresentaram comportamento UCST (upper critical solution temperature), sendo que a separação de fases L-L ocorre a temperaturas superiores à separação de fases S-L. O modelo de interações binárias prevê que a curva de separação L-L para as soluções EVOH- 38/DMF esteja situada a temperaturas superiores em relação às soluções EVOH-32/DMF e indica que a separação de fases resulta da baixa afinidade entre segmentos hidrofóbicos do EVOH com os segmentos do polímero contendo hidroxila e com o solvente, DMF, concordando com os dados obtidos experimentalmente. Filmes de EVOH obtidos pela evaporação do solvente mostraram-se densos, sem a presença de poros. As soluções ternárias também apresentaram comportamento UCST, resultando em duas fases macroscópicas, F1 e F2, à temperatura ambiente. A composição destas fases foi determinada por Análise Termogravimétrica (TGA), e os resultados mostraram que uma das fases macroscópicas é rica em EVOH e outra fase é rica em PMMA. As blendas resultantes da secagem dos sistemas ternários apresentaram duas camadas: uma densa e rica em PMMA e outra porosa e rica em EVOH. A presença de PMMA foi decisiva à formação de estruturas porosas
Abstract: In this work blends of poly (ethylene-co-vinyl alcohol) (EVOH), a semicrystalline copolymer which combines hydrophobic and hydrophilic segments and poly (methyl methacrylate) (PMMA), an amorphous and hydrophilic polymer were studied. EVOH blends, with ethylene content ranging from 27 to 44 mol% and PMMA were prepared by casting from solutions in DMF, and by mixing into a mini-mixer, with the objective of: i) evaluate the phase behavior and the morphology of the blends, EVOH/PMMA, depending on the composition of mixtures, the ethylene contents in the copolymers of EVOH and the conditions of mixing; ii) obtain the phase diagrams of the binary and ternary solutions, EVOH/DMF and EVOH/PMMA/DMF, respectively, by the process of thermally induced phase separation (TIPS). The phase behavior of the blends, EVOH / PMMA, was investigated by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The morphology of the blends was investigated by Scanning Electron Microscopy (SEM). The blends independently of the method of preparation and of the composition are immiscible. As a result of immiscibility, the melting temperature (Tm) and the crystallization temperature (Tc) are not affected by the presence of PMMA. The morphology of the blends varies with the composition and with the method of preparation. The blends produced by the mechanical method is compact, showing morphology of dispersed phase in a matrix, with inversion of phases in about 50% by weight of each component. The binary solutions, EVOH-38/DMF and EVOH-32/DMF, were submitted to experiments to determine the cloud temperature (Tcloud) by optical microscopy, and the dynamic crystallization (Tcd), by DSC. The binary solutions show UCST behavior (upper critical solution temperature), and the L-L phase separation occurs at higher temperatures than the S-L phase separation. The binary interaction model provides the L-L line to the EVOH-38/DMF, solutions which was situated at higher temperatures than the EVOH-32/DMF solutions and indicates that the phase separation results from the low affinity between the hydrophobic segments of EVOH with the segments of the polymer containing hydroxyl and the solvent, DMF, which agrees with the data obtained experimentally. Films of EVOH obtained by the solvent evaporating seemed to be dense, without the presence of pores. The ternary solutions also had UCST behavior, resulting in two macroscopic phases, F1 and F2, at room temperature. The phase compositions were determined by Thermogravimetric Analysis (TGA), and the results showed that one of the macroscopic phases is rich in EVOH and the other phase is rich in PMMA. The blends resulting from drying of ternary systems had two layers: a dense and rich in PMMA and another porous and rich in EVOH. The presence of PMMA was crucial to the formation of porous structures
Doutorado
Físico-Química
Doutor em Ciências
Elmsjö, Albert. „Selectivity in NMR and LC-MS Metabolomics : The Importance of Sample Preparation and Separation, and how to Measure Selectivity in LC-MS Metabolomics“. Doctoral thesis, Uppsala universitet, Avdelningen för analytisk farmaceutisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-318296.
Der volle Inhalt der QuelleMarchand, Jean-Pierre. „Relaxation magnétique nucléaire dans les solutions ternaires de polyacrylonitrile ou de polyacrylonitrile-co-méthallylsulfonate de sodium : détermination et caractérisation du diagramme de phases“. Grenoble 1, 1993. http://www.theses.fr/1993GRE10193.
Der volle Inhalt der QuelleTilli, Paola. „Production, characterization and modeling of hollow fiber membranes for biogas purification“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Den vollen Inhalt der Quelle findenMarques, Rosalva dos Santos. „Comportamento de fases de soluções de poliolefinas funcionalizadas e implicação na obtenção de membranas pelo processo TIPS“. [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248781.
Der volle Inhalt der QuelleTese (doutorado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: Neste trabalho, estudou-se o comportamento de fases de soluções binárias e ternárias de poliolefinas funcionalizadas com hidroxilas (EVOH) e ácido carboxílico (PEAA) nos solventes dimetilformamida e álcool benzílico. Utilizou-se EVOH contendo 27 e 44 mol % e PEAA contendo 80 mol % de etileno. As soluções exibem o comportamento de fases do tipo UCST, apresentando separações de fases líquido-líquido (L-L) e sólido-líquido (S-L). As temperaturas de separação de fases L-L e S-L, TL-L e TS-L, respectivamente, foram determinadas para soluções com diferentes composições por inspeção visual e por DSC, respectivamente. Enquanto TS-L para as soluções binárias de EVOH varia fortemente da com a composição das soluções binárias, TS-L para as soluções binárias de PEAA é praticamente constante. Estes resultados foram interpretados sob a ótica de um modelo em que a cristalização do PEAA, que envolve os segmentos de etileno do copolímero, ocorre quase na ausência de solvente. Já a cristalização do EVOH, que envolve os segmentos hidroxilados, ocorre em meio ao solvente, em uma condição em que o potencial químico do polímero varia com a composição da solução. Este modelo pode ser comprovado por estudos de fluorescência empregando-se o pireno e o acetato de uranila como sondas hidrofóbica e hidrofílica, respectivamente. Estes estudos de fluorescência permitiram também acessar transições não detectáveis por DSC. As soluções ternárias homogêneas apresentam mais de uma separação de fases L-L quando submetidas a resfriamento. O diagrama de fases ternário foi construído determinando-se as composições das soluções em equilíbrio, decorrentes da primeira separação de fases L-L, por termogravimetria de alta resolução. Os diagramas de fases das soluções ternárias resultantes das combinações possíveis entre os diferentes polímeros e solventes apresentam regiões de miscibilidade limitadas localizadas em regiões próximas aos vértices, sendo as composições das fases em equilíbrio características de cada combinação nas soluções ternárias. Os materiais resultantes da evaporação do solvente de soluções submetidas ao processo TIPS (Temperature Induced Phase Separation) são compactos ou porosos, dependendo da afinidade polímero-solvente. Entretanto, as morfologias dos materiais resultantes de soluções ternárias submetidas ao processo TIPS são únicas e características do par polímero-polímero, demonstrando que a estratégia de combinação de polímeros para controlar a morfologia é viável
Abstract: The phase behavior of binary and ternary solutions of functionalized poliolefins with hydroxyls (EVOH) and carboxylic acid (PEAA) were studied using dimethylformamide and benzyl alcohol as solvents. PEAA containing 80 mol % and EVOH containing 27 and 44 mol % of ethylene were used. The binary and ternary solutions present a typical UCST behavior associated to liquid-liquid (L-L) and solid-liquid (S-L) phase separation. The temperatures related to L-L and S-L phase separation, TL-L e TS-L, respectively, were determined visually and using DSC, respectively. While TS-L depends on the EVOH solution composition, it is practically constant for PEAA solutions. These results were explained using a model in which the crystallization of PEAA from the solution occurs in absence of solvent, once it involves the polyethylene segments. On the contrary, the crystallization of EVOH from the solution, that involves the hydroxylated segments, occurs in presence of the solvent. This condition leads to the decrease of the chemical potential of EVOH in the solution. The models could be proved by fluorescence experiments using pyrene and uranyl acetate as hydrophobic and hydrophilic probes, respectively. Moreover, the fluorescence experiments allow accessing other transitions not detectable by DSC for ternary solutions. The homogeneous ternary solutions present more than one L-L phase separation by cooling. The ternary diagram was determined by the first L-L phase separation using the composition data accessed by high resolution thermogravimetry. The ternary solutions of all possible combination of polymers and solvents show a restricted miscibility window in the regions near the vertices. The composition of the phases in equilibrium is characteristic of each ternary solution, as well as, the morphology of the materials resulting from the evaporation of the solvent after the solution being subjected to TIPS (Temperature Induced Phase Separation) process. This process applied to binary and ternary solutions resulted in dense or porous materials depending on the polymer-solvent affinity. However, the morphology resulting from ternary solutions subjected to TIPS process and solvent evaporation is unique, showing that the strategy of combining different polymers is a viable route to control the morphology of polymers
Doutorado
Físico-Química
Doutora em Ciências
Anselmi, Hélène. „Modélisation et évaluation environnementale d’une unité de captage de CO₂ intégrée à un procédé industriel“. Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0080.
Der volle Inhalt der QuelleLimiting carbon dioxide (CO2) emissions is a major global issue, particularly for the energy, chemical and metallurgical industries. To this end, CO2 capture technologies have been developed in recent decades. In this study, we focused on three types of CO2 capture technologies: chemical absorption by MEA, membrane separation and activated carbon adsorption. The CO2 considered is emitted by a coal-fired power station and then directly valorized within a manufacturing process on the same site. The objective of this study was to quantify the environmental benefits of installing a CO2 capture technology in comparison to the current configuration, without CO2 capture. Our approach combined process modeling and life cycle assessment. The methodology adopted was to model the complete system (the power plant, the manufacturing process and the various capture units) using a flowsheeting software (Aspen Plus), then to determine the environmental impacts by LCA. The results show that the MEA chemical adsorption process is strongly penalized by the use of the solvent, both regarding the energy consumption and the environmental impacts. The membrane process exhibits significant environmental impacts, despite a much lower energy consumption, due to the massive use of polymers (membrane materials). Finally, the activated carbon adsorption process has lower environmental impacts than the other two processes in the vast majority of impact categories
Anselmi, Hélène. „Modélisation et évaluation environnementale d’une unité de captage de CO₂ intégrée à un procédé industriel“. Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0080.
Der volle Inhalt der QuelleLimiting carbon dioxide (CO2) emissions is a major global issue, particularly for the energy, chemical and metallurgical industries. To this end, CO2 capture technologies have been developed in recent decades. In this study, we focused on three types of CO2 capture technologies: chemical absorption by MEA, membrane separation and activated carbon adsorption. The CO2 considered is emitted by a coal-fired power station and then directly valorized within a manufacturing process on the same site. The objective of this study was to quantify the environmental benefits of installing a CO2 capture technology in comparison to the current configuration, without CO2 capture. Our approach combined process modeling and life cycle assessment. The methodology adopted was to model the complete system (the power plant, the manufacturing process and the various capture units) using a flowsheeting software (Aspen Plus), then to determine the environmental impacts by LCA. The results show that the MEA chemical adsorption process is strongly penalized by the use of the solvent, both regarding the energy consumption and the environmental impacts. The membrane process exhibits significant environmental impacts, despite a much lower energy consumption, due to the massive use of polymers (membrane materials). Finally, the activated carbon adsorption process has lower environmental impacts than the other two processes in the vast majority of impact categories
Behloul, Chakib Rafik. „Méthodes de conception de réacteurs multifonctionnels (réacteur-échangeur-séparateur) : application à la synthèse directe de DME à partir de CO₂ et d’H₂“. Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0249.
Der volle Inhalt der QuelleThe depletion of resources and the accumulation of pollutant gases in the atmosphere are nowadays of growing concern. The current energy transition requires that certain material and energy transformation processes be partially modified or profoundly reconsidered to fit more sustainable operating conditions. Low-carbon electricity and hydrogen can substitute fossil fuels, leading to an energy mix with a low greenhouse gas (GHG) footprint. In addition to hydrogen, the production of alternative fuels and high value-added products is another way to support the energy transition.Looking for optimal, sustainable and economical processes is therefore a major challenge that process engineers are facing. The present work has thus focused on the intensification of mass and energy transformation processes, through multifunctional units, which take advantage of the synergies between elementary functions of transformation (reaction, transfer, separation, etc.) within an intensive equipment. The concept of multifunctional reactors, coupling several elementary functions, has been a real success when historical demonstrators were created (Eastman-Kodak process, etc.), but their implementation has not been generalized, due to a lack of practical design methodology.This work focuses on the implementation of some intensification methodologies to understand and improve the performance of a process involving balanced exothermic reactions. The dimethyl ether (DME) direct synthesis from CO₂ and H₂ is considered as a case study. Different exploratory ways for the DME direct synthesis process development have been investigated based on modeling and simulation. Reactor- Heat exchanger, multifunctional reactor (reactor-heat exchanger-membrane separator), hybrid elementary block processes and a process involving the cooled reactor in a conventional process environment in the presence of additional unit operations and recycle loop are studied from different angles. Different optimization cases and strategies have been addressed which differ by the decision variables and the solving method. The different methodologies applied have demonstrated the relevance of the solutions obtained and the opening towards process innovation.At the equipment level, the profiles optimization represents the heart of the methodology. The results demonstrate the potential of multifunctional reactors: a CO₂ conversion per pass of 98%, a DME yield of 95% and the possibility to remove a distillation column are obtained. In order to assess the maximum achievable performance in a multifunctional reactor, a hybrid process of elementary blocks has been optimized. At the process scale, the reactor behavior has been studied to further understand the impact of the reactor integration in a recycle loop and to estimate the local and global effects on the multiple performance criteria. Based on various criteria (overall DME yield, overall CO₂ conversion, TRL, etc.), the comparison of the different designs revealed that a reduction of the equipment number by a factor of 11 is possible in the case of a multi-functional reactor choice
Norén, Sara, und Theresé Thyselius. „Nollseparation mellan förälder och nyfött barn : En begreppsanalys ur barnmorskans perspektiv“. Thesis, Högskolan Dalarna, Sexuell, reproduktiv och perinatal hälsa, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:du-36033.
Der volle Inhalt der QuelleBackground: Zero-separation has no distinct definition and appears to be a relatively new concept used in delivery- and postpartum care. There are obvious guidelines that the child should be skin-to-skin with the mother after birth. But in some cases the mother and child are separated for different reasons. The midwife has a central part in the care of emergent mothers’ and their newborn children.Aim: The aim in this study was to analyze and define the concept of zero-separation between parent and infant from a midwifes’ perspective.Method: A concept analysis based on a hybridmodel. The hybrilmodel is divided into a theoretical phase with literature search, a field study phase based on interviews with six clinically active midwives and a summary synthesis phase.Results: Zero-separation is equated with; skin-to-skin, always have a parent present, the family being together always and that couplet care is needed to maintain zero-separation. The midwife has a significant keyrole in maintaining zero-separation. Conclusion: Zero-separation is an umbrellaconcept which involves skin-to-skin, parental presence, that the family should be allowed to be together, a functioning couplet care between different instances and that maintaining zero-separation is a part of the midwifes’ assignments.Clinical application: The results from this study can be useful in delivery- and aftercare, but the competence needs to be increased in other instances in healthcare that may come in contact with newborn children and their parents.