To see the other types of publications on this topic, follow the link: Hydration process.
Dissertations / Theses on the topic 'Hydration process'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 37 dissertations / theses for your research on the topic 'Hydration process.'
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
Wei, Xiaosheng. "Interpretation of hydration process of cement-based materials using resistivity measurement /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20WEI.
Full textAbstract:
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 168-186). Also available in electronic version. Access restricted to campus users.
2
Xiao, Lianzhen. "Interpretation of hydration process of concrete based on electrical resistivity measurement /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202007%20XIAO.
Full text
3
Wen, Yanli. "Cement microstructure evolution during the hydration process for nuclear waste immobilisation." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/cement-microstructure-evolution-during-the-hydration-process-for-nuclear-waste-immobilisation(a23c033a-5180-45bc-bb10-21ec149fbeec).html.
Full textAbstract:
Cement has been selected for wastes immobilization as a simple, low temperature and low cost process for decades. The mechanical and immobilization properties of cement are mainly decided by cement hydration process, especially in the first 24 hours. Previous methods for studying the cement hydration are those include isothermal calorimetry, continuous monitoring of chemical shrinkage, in situ quantitative X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), quasi-elastic neutron scattering (QENS) and small angle neutron scattering (SANS). Few available in-situ imaging methods were successfully used for net rate study of cement hydration. In this Ph.D. research, innovative imaging techniques such as X-ray computed tomography (XCT) combined with 2D SEM-BSD analysis were combined to study the microstructure and phase change of cement or cement & SrCl2 mixture during hydration. Digital Volume Correlation (DVC) and Digital Image Correlation (DIC) were applied to study the chemical volume shrinkageand drying shrinkage of cement samples during hydration. The effects of SrCl2 simulating the radioactive nuclide from nuclear waste on cement hydration were studied by XRD and ICP-AES techniques. These studies verified that the hydration net rate could be characterised by XCT imaging techniques and the volume shrinkage of cement or cement& SrCl2 mixture during hydration could be characterised by the DVC and DIC techniques.
4
Bergold, Sebastian Tobias [Verfasser], and Jürgen [Gutachter] Neubauer. "The process of alite hydration: Implications from quantitative phase analysis of Calcium-Silicate-Hydrate during hydration and from acceleration of the hydration reaction by mechanical activation / Sebastian Tobias Bergold ; Gutachter: Jürgen Neubauer." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2016. http://d-nb.info/1124233946/34.
Full text
5
Pastor, Alberto Claudio Miano. "Description of grains hydration kinetics and its enhancement using the ultrasound technology." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/11/11141/tde-05012016-164029/.
Full textAbstract:
The present work had as objective to study the hydration process of grains and its possible enhancement using the ultrasound technology. For that, it was studied the hydration kinetics of different grains (Andean lupin, Adzuki beans, sorghum grains and corn kernels) correlating the morphology with mathematical models and the mass transfer mechanisms. Moreover, the effect of the soaking water temperature and the grain initial moisture content were studied to complement the description of this process. The ultrasound application was studied for improving the hydration process, describing the possible mechanisms (direct and indirect effects) that improve the mass transfer process. Therefore, it was established the way by how water enters in the studied grains, demonstrating that the water transfer into the grains is a complex phenomenon and takes place not only due to diffusional mechanisms, but also by capillarity. In addition, suitable mathematical models were proposed and used to explain the processes, describing their parameters according to the grains morphology and the mass transfer mechanisms. Further, it was determined how ultrasound enhances the mass transfer and in which conditions the direct (inertial flow and sponge effect) and the indirect effects (micro channels formation by acoustic cavitation) take place in the process, maximizing the effect of this technology. Finally, it was demonstrated that the ultrasound technology enhanced the hydration process for corn kernels, reducing significantly the process time in approximately 35 %, without modifying the thermal, structural and rheological properties of their starch. In conclusion, the present work improved the description of the grain hydration phenomenon and proved that the ultrasound technology can be used to enhance this process without changing its main industrial component. It is highlighted that the obtained results are thus high desirable for both the industrial and academic point of view.O presente trabalho teve como objetivo estudar o processo de hidratação de grãos e sua possível melhora usando a tecnologia do ultrassom. Estudou-se a cinética de hidratação de diferentes grãos (tremoço andino, feijão Adzuki, grãos de sorgo e grãos de milho) correlacionando a morfologia com modelos matemáticos e os mecanismos de transferência de massa. Também foi estudado o efeito da temperatura e o conteúdo de umidade inicial do grão para complementar a descrição deste processo. Estudou-se a aplicação do ultrassom no processo de hidratação descrevendo-se os possíveis mecanismos (efeito diretos e indiretos) que melhoram a transferência de massa. Como resultado, foi estabelecida a forma como a água entra nos grãos estudados, demostrando que a transferência de água dentro dos grãos é um fenômeno complexo e que acontece por difusão e capilaridade. Foram propostos e utilizados modelos matemáticos apropriados para explicar os processos, descrevendo os parâmetros de acordo com a morfologia dos grãos e os mecanismos de transferência de massa. Ainda, determinou-se como o ultrassom melhora a transferência de massa e em que condições do processo acontecem os efeitos diretos (fluxo inercial e efeito esponja) e efeitos indiretos (formação de micro canais pela cavitação acústica), maximizando o efeito dessa tecnologia. Finalmente, demonstrou-se que a tecnologia do ultrassom melhora o processo de hidratação de grãos de milho, diminuindo significativamente o tempo do processo em cerca de 35 % sem alterar as propriedades térmicas, reológicas e estruturais do seu amido. Como conclusão, o presente trabalho melhorou a descrição de como os grãos são hidratados, demonstrando que o ultrassom pode ser usado para melhorar o processo de hidratação de grãos sem alterar os seus principais produtos industriais. Ressalta-se que os resultados obtidos são desejáveis tanto do ponto de vista acadêmico quanto industrial.
6
HAUSMAN-MANNING, DEBRA SUE. "APPLICATION OF PROCESS ANALYTICAL TECHNOLOGY TO PHARMACEUTICAL PROCESSES." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1108838053.
Full text
7
Koláček, Tomáš. "Pojiva a malty ze síranu vápenatého." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392362.
Full textAbstract:
This diploma thesis deals with the study of the binder mortar based on calcium sulphate. The theoretical part deals with the general theory of sulfate binders and anhydrite mortars. Further attention is paid to the standard requirements for these binders and mortars and the evaluation of the existing research at the THD Institute. The experimental part is devoted to research of anhydrite mortar for the production of self-leveling mixtures. The subject of the research was the design of a suitable activating agent, performing technological tests on designed anhydrite pastes and mortars and monitoring hydration.
8
Verner, Filip. "Studium hydratačního procesu anhydritových maltovin." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265222.
Full textAbstract:
The presented work deals with the study of hydration processes anhydrite binders with external exciters. Work is divided into two parts. Conceptually is this work divided into two parts The theoretical part of study contains general theory of gypsum binders, anhydrite binders and research at the institude THD. In the experimental part deals with proposal of recipes, making of samples and subsequent determination of main technological tests and monitoring hydration process by the XRD and DTA analysis.
9
Lalsare, Amoolya Dattatraya. "High Pressure Steam Reactivation of Calcium Oxide Sorbents For Carbon Dioxide Capture Using Calcium Looping Process." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1462444410.
Full text
10
Imam, Rayees Ahamed Verfasser], and Kai [Akademischer Betreuer] [Sundmacher. "Evaluation of process concepts for liquid-liquid systems exemplified for the indirect hydration of cyclohexene to cyclohexanol / Rayees Ahamed Imam. Betreuer: Kai Sundmacher." Magdeburg : Universitätsbibliothek, 2014. http://d-nb.info/1060096072/34.
Full text
11
Budiarto, Thomas [Verfasser], Jens-Uwe [Akademischer Betreuer] Repke, Jens-Uwe [Gutachter] Repke, and Peter [Gutachter] Strasser. "Modeling process dynamics in membrane-electrolyte-assemblies of chloralkali electrolyzers considering steric and hydration effects / Thomas Budiarto ; Gutachter: Jens-Uwe Repke, Peter Strasser ; Betreuer: Jens-Uwe Repke." Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1230468374/34.
Full text
12
Yu, Fu-Chen. "Reactivation Mechanism Studies on Calcium-Based Sorbents and its Applications for Clean Fossil Energy Conversion Systems." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1298957301.
Full text
13
Magrla, Radek. "Modifikace vlastností portlandských cementů orientovaná na snížení emisí CO2." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225907.
Full textAbstract:
This thesis aims to burn raw material with a lower content of carbonate component for the production of Portland cement. Substitution of carbonate component is done by fluidized fly ash. The model cements are tested of basic technological properties and the hydration process is observed.
14
Břicháčková, Jana. "Výzkum v oblasti anhydritových pojiv." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-226712.
Full textAbstract:
The presented work deals with research in the field of sulfate binders on the anhydrite base. Conceptually, it is divided into a general theory of sulfate binders and anhydrite mortar compounds, which is describing in detail the using of anhydrite mortar compounds on the poured floor screeds, and then the experimental part, where is made the mineralogical analysis of seven different gypsum resources and subsequent is monitored the effect of two sulfate exciters on the achieved technological properties and hydration process.
15
Sims, Jesse N. L. "Exploration of fluid intake practices in endurance running." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/226656/1/Jesse_Sims_Thesis.pdf.
Full textAbstract:
Utilising a survey based approach, this thesis aimed to understand how fluid intake practices differ among endurance runners and characterise how fluid practices may reflect performance outcomes. The findings from this study indicate that collectively there is no difference between sex when exploring fluid intake beliefs and behaviours towards hydration optimisation strategies. This suggests that human behaviour is influential in understanding fluid intake practices in endurance runners. Fluid intake optimisation strategies are highly individualised and further research is still required to shape the avenue for future fluid intake recommendations.
16
Hendricks, Nicolette Rebecca. "The application of high capacity ion exchange adsorbent material, synthesized from fly ash and acid mine drainage, for the removal of heavy and trace metal from secondary Co-disposal process waters." Thesis, University of the Western Cape, 2005. http://hdl.handle.net/11394/1455.
Full textAbstract:
In South Africa, being the second largest global coal exporter, coal mining plays a pivotal role in the growth of our economy, as well as supplying our nation’s ever increasing electricity needs; while also accounting for more than 10% of the 20 x 109 m3 water used annually in the country. Coal mining may thus be classified as a large-scale water user; known to inevitably generate wastewater [acid mine drainage (AMD)] and other waste material, including fly ash (FA). Current and conventional AMD treatment technologies include precipitation–aggregation (coagulation/flocculation) – settling as hydroxides or insoluble salts. The process stream resulting from these precipitation processes is still highly saline, therefore has to undergo secondary treatment. The best available desalination techniques include reverse osmosis (RO), electro dialysis (ED), ion exchange and evaporation. All available treatment methods associated with raw AMD and its derived process stream fall prey to numerous drawbacks. The result is that treatment is just as costly as the actual coal extraction. In addition, remediation only slows the problem down, while also having a short lifespan. Research conducted into converting fly ash, an otherwise waste material, into a marketable commodity has shown that direct mixing of known ratios of FA with AMD to a pre-determined pH, erves a dual purpose: the two wastes (AMD and FA) could be neutralized and produced a much cleaner water (secondary co-disposal [FA/AMD]-process water), broadly comparable to the process water derived from precipitation-aggregation treated AMD. The collected post process solid residues on the other hand, could be used for production of high capacity ion exchange material (e.g. zeolite A, faujasite, zeolite P, etc.). The produced ion exchange material can subsequently be utilized for the attenuation of metal species in neutralized FA/AMDprocess waters.Magister Scientiae - MSc
17
Butler, Marko, Simone Hempel, and Viktor Mechtcherine. "Zeitliche Entwicklung des Verbundes von AR-Glas- und Kohlenstofffaser- Multifilamentgarnen in zementgebundenen Matrices." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244045698955-31655.
Full textAbstract:
Mit zunehmendem Alter zeigt das Verbundverhalten von Multifilamentgarnen aus alkaliresistentem Glas (AR-Glas) oder Kohlenstoff in Abhängigkeit von der Zusammensetzung der zementgebundenen Matrix eine sehr unterschiedliche Entwicklung. Während bei AR-Glas teilweise drastische Verluste des Leistungsvermögens zu verzeichnen sind, treten diese bei Kohlefasern nicht auf. Zur Untersuchung der Phänomene wurden beidseitige Garnauszugversuche durchgeführt und die Interphase zwischen Filamenten und Matrix im Rasterelektronenmikroskop (ESEM) untersucht. Die unterschiedlichen mechanischen Eigenschaften stehen in Zusammenhang mit verschieden ausgeprägten Mikrostrukturen der Interphasen. Welche Ursachen die unterschiedliche morphologische Entwicklung der Interphasen hat, ist Gegenstand aktueller Arbeiten.
18
Ramkumar, Shwetha. "CALCIUM LOOPING PROCESSES FOR CARBON CAPTURE." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274882053.
Full text
19
Vávrová, Alžběta. "Příprava modifikovaných trikalciumaluminátových fází a studium jejich hydratačních procesů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401853.
Full textAbstract:
This diploma thesis deals with the preparation of modified tricalcium aluminate phases using sodium ions, and the study of their hydration processes and products. The X-ray diffraction analysis, isothermal calorimetry, laser diffraction, and scanning electron microscopy with energy dispersion analysis were used to solve this task. The preparation of modified tricalcium aluminate phases using high temperature methods has been described in the experimental section. Furthermore, the X-ray diffraction analysis was used to determine the purity of the prepared phases and the scanning electron microscopy with energy dispersion analysis was used to define the volume of sodium. Laser diffraction was used to measure a particle size distribution in the individual phases. Subsequently, hydration of the pure phases was performed in an isothermal calorimeter. It was followed by hydration of phases in the presence of different gypsum content and then in the presence of saturated portlandite solution. Hydration of some samples was stopped in order to better understand the hydration process. Hydration products were studied by X-ray diffraction analysis. The obtained results were compared with each other and the influence of sodium ions on both the structure of the prepared phases and the course of hydration and its products has been discussed. The effect of adding different volumes of gypsum and portlandite on the course of hydration of the individual phases was also compared.
20
Govin, Alexandre. "Aspects physico-chimiques de l'interaction bois - ciment. Modification de l'hydratation du ciment par le bois." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2004. http://tel.archives-ouvertes.fr/tel-00012091.
Full textAbstract:
L'utilisation de bois dans une matrice cimentaire confère des propriétés intéressantes aux composites. L'importance des variations dimensionnelles et des retards de prises du matériau sont deux problèmes majeurs. Le but de ce travail était de mieux comprendre les mécanismes d'interaction entre le bois et le ciment. Nous avons étudié l'influence, de la fibre de peuplier naturel et de la fibre de peuplier stabilisée dimensionnellement par traitement thermique, sur l'hydratation du ciment. Compte tenue du rôle de la composition chimique de bois sur la prise du ciment, l'étude a été consacrée à l'obtention de données concernant l'essence utilisée (peuplier) : propriété hygroscopique, analyse structurale, analyse chimique des extraits aqueux et influence du traitement thermique sur ces propriétés.La fibre végétale modifie essentiellement l'hydratation des phases silicatés. Une forte inhibition de la précipitation de la portlandite et des CSH est apparue. Cette dernière provient d'un déficit d'ions hydroxydes dans la phase interstitielle. En présence de bois, l'ettringite est stabilisée et sa conversion en monosulfoaluminate retardée. Il est apparut que le bois ne modifiait pas la dissolution totale des grains anhydres.
Le milieu alcalin, imposé par le ciment, dégrade les hémicelluloses, les parties amorphes de la cellulose et les lignines du peuplier. Il en résulte une forte production d'acides organiques dans la phase interstitielle. Ces derniers présentent un effet retard sur l'hydratation nettement supérieur à celui généré par les extractibles.
21
Almeida, Luara de Jesus. "Modelagem e otimização do processo de hidratação de cereal matinal com leite." Universidade Federal do Tocantins, 2017. http://hdl.handle.net/11612/537.
Full textAbstract:
Os cereais matinais são produtos extrusados de alto teor de proteína, carboidratos e fibras, que
são consumidos com leite. A modelagem matemática é essencial para predizer e simular o
comportamento dos materiais submetidos à hidratação, com o intuito de descobrir as melhores
condições de temperatura e de tempo de hidratação do processo. Esse trabalho teve como
objetivo modelar e otimizar o processo de hidratação de cereal matinal com leite, visando
encontrar as variáveis ideais de tempo e temperatura de hidratação, bem como a proporção de
leite e cereal para obtenção de um produto pronto para o consumo, além de utilizar dois
modelos matemáticos e rede neural artificial para simular a cinética de absorção de leite. A
hidratação foi conduzida em 3 proporções de cereal/leite e 3 temperaturas de imersão durante
duas horas, com cereal de milho (sem açúcar) e leite UHT integral. Os tratamentos utilizados
na hidratação (proporção, temperatura e tempo) causaram efeito significativo (p < 0.05) em
todas as propriedades físico-químicas do cereal matinal hidratado com leite. Dos modelos
matemáticos, o modelo de Peleg foi o que melhor descreveu a cinética de absorção de leite no
cereal nas temperaturas e proporções investigadas, e obteve bons ajustes aos dados
experimentais. A aplicação da rede neural artificial representou de forma satisfatória a
cinética de absorção do leite.Breakfast cereals are extruded products with a high content of protein, carbohydrates and fibers, which are consumed with milk. The mathematical modeling is essential to predict and simulate the behavior of the materials submitted to hydration, in order to discover the best conditions of temperature and hydration time in the process. The objective of this work was to model and optimize the process of breakfast cereal hydration with milk, aiming to find the ideal variables of time and temperature of hydration, as well as the proportion of milk and cereal to obtain a product ready for consumption, besides using two mathematical models and Artificial Neural Network to simulate the kinetics of milk absorption. Hydration was conducted in 3 cereal/milk proportions and 3 immersion temperatures for two hours, with corn cereal (without sugar) and integral UHT milk. The treatments used in hydration (proportion, temperature and time) had a significant effect (p <0.05) on all physical-chemical properties of breakfast cereal hydrated with milk. About mathematical models, the Peleg’s model best described the kinetics of milk absorption in the cereal at the temperatures and proportions investigated, and obtained good adjustments to the experimental data. The application of Artificial Neural Network satisfactorily represented the kinetics of milk absorption.
22
Peschard, Arnaud. "Aspects physico-chimiques de l'interaction ciment-polysaccharides." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2003. http://tel.archives-ouvertes.fr/tel-00089164.
Full textAbstract:
Les polysaccharides sont des retardateurs de prise qui confèrent au mortier une excellente rétention d'eau et une augmentation de la durée de maniabilité. Dans le but de rationaliser l'emploi de ces adjuvants dans les mortiers industriels, nous avons étudié l'effet de leur introduction sur l'hydratation du ciment afin d'élucider les mécanismes d'interaction.Compte tenu du peu d'informations disponibles sur ces adjuvants et du constat que les propriétés du mortier sont fortement dépendantes du polysaccharide introduit, nous avons tout d'abord réalisé une étude des matières premières. Nous avons aussi rassemblé des données structurales sur les adjuvants (nature du substituant, masse moléculaire moyenne).
L'étude de l'hydratation du ciment adjuvanté en milieu dilué (EC=20) permet de proposer des mécanismes. Les polysaccharides n'agissent ni sur la dissolution du ciment, ni sur la germination-croissance des premiers hydrates. Le mécanisme prépondérant semble être l'adsorption sur les premiers hydrates ralentissant ou bloquant ainsi l'hydratation.
L'étude en milieu concentré (EC<0,5) se rapproche des conditions réelles d'utilisation. La détermination des teneurs en hydrates montre que parmi les adjuvants, l'éther d'amidon et la dextrine AM2 sont les retardateurs les plus forts. Pour ces adjuvants, d'une part l'ettringite est stabilisée et d'autre part les formations des CSH et de la portlandite sont retardées.
Une discussion des différents mécanismes d'interaction possibles est abordée.
23
Husson, Sophie. "Étude physicochimique et mécanique des interactions ciment-fillers. Application aux mortiers." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1991. http://tel.archives-ouvertes.fr/tel-00844622.
Full textAbstract:
Cette recherche est consacrée à l'étude des interactions entre les fillers et le ciment. Ces interactions peuvent avoir une origine physique et/ou chimique. L'utilisation d'un filler de référence, inerte chimiquement (une zircone), permet de séparer les deux effets. Nous montrons que les fillers (calcaire et zircon) de par leur activité chimique peuvent agir favorablement sur les propriétés mécaniques des pâtes pures et des mortiers. Ils ont un effet accélérateur et participent à la formation des espèces hydratées. Une partie importante de l'étude concerne l'interaction du filler calcaire avec le constituant principal du ciment, à savoir: le silicate tricalcique. L'activité chimique des fillers varie suivant leurs origines et les traitements qu'ils subissent. Le broyage peut être à l'origine de la création de défauts planaires, linéaires et ponctuels. Ceux-ci déterminent la réactivité du filler. Il existe une relation entre cette activité chimique et les propriétés mécaniques des pâtes pures. Cette corrélation nous permet de préconiser un test de sélection des fillers calcaires.
24
Brun, Catherine. "Modélisation de la cinétique de réduction d'oxydes d'uranium par l'hydrogène. Réactivités de germination et de croissance." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1997. http://tel.archives-ouvertes.fr/tel-00842470.
Full textAbstract:
Le but de cette étude est de modéliser la réaction de réduction par l'hydrogène de l'octooxyde de triuranium, U3O8 (obtenu par calcination de trioxyde d'uranium), en dioxyde d'uranium. Il s'agit de construire un modèle complet comportant un modèle géométrique et deux mécanismes physico-chimiques de croissance et de germination permettant d'interpréter l'ensemble des résultats expérimentaux. Les courbes cinétiques ont été obtenues par analyse thermogravimétrique, en isotherme et sous atmosphère controlée : pressions de vapeur d'eau et d'hydrogène fixées. Le modèle géométrique qui a permis d'interpréter l'allure des courbes cinétiques et des courbes de vitesse est un modèle de germination-croissance anisotrope. La poudre est supposée constituée de grains sphériques de même rayon. Les germes de la nouvelle phase, UO2, apparaissent à la surface des grains d'U3O8 avec une fréquence spécifique de germination. La réactivité de croissance est anisotrope et est très grande dans la direction tangentielle à la surface des grains ; en conséquence, dès qu'un germe apparaît à la surface d'un grain, celui-ci est instantanément recouvert d'une couche de la nouvelle phase. Ensuite, le développement du dioxyde d'uranium se fait vers l'intérieur du grain et l'étape limitante est située à l'interface externe, c'est à dire la surface du grain. Les variations de la réactivité de croissance et de la fréquence spécifique de germination en fonction des pressions partielles des gaz et de la température ont été interprétées par deux mécanismes distincts. L'étape limitante du mécanisme de croissance est la désorption de l'eau de la surface du dioxyde d'uranium. Pour le mécanisme de germination, l'étape limitante est également une désorption d'eau mais de la surface de l'octooxyde de triuranium. Le même modèle géométrique et les mêmes mécanismes de germination et de croissance ont pu être appliquées à la réduction d'un octooxyde de triuranium obtenu par calcination de trioxyde d'uranium hydrate. Les valeurs de la fréquence spécifique de germination de ce solide sont cependant plus faibles que celles du solide obtenu par calcination directe de trioxyde d'uranium.
25
Chia-Nan, Hsia, and 夏佳男. "The microstructure and hydration process of high finenessslag concrete." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/vpv24g.
Full textAbstract:
碩士國立臺灣大學
土木工程學研究所
107
In recent years , in order to save cement consumption,the construction industry will replace cement with pozzolan materials as binder materials in concrete.Pozzolan materials include slag, fly ash, silica fume , depending on the type of material added,concrete will exhibit different characteristics.Pozzolan materials with different sources、chemical compositions、physical feature added into concrete would show big difference in concrete’s performance.Slag is a kind of pozzolan materials, it is a by-product of steel making. When the fineness of slag increases, as result of increase in surface area, the hydration process would become faster than slag with normal fineness. High fineness slag’s microstructural properties and engineering properties are dinstinct from normal pozzolan material added concrete. Topics of concrete materials are changing from macroscopic engineering properties into microstructural properties. By conducting different kinds of microstructural experiments to understand the mechanism of materials reaction ,hoping by altering properties of materials can achieve target concrete performances. This research is manily using high fineness slag ,normal fineness slag to replace cement as binder material system,designing three slag replacement ratios with five ages.Conducting three types of microstructural experiments including XRD diffraction ,TG/DTA analysis, MIP and apply these three experiments’ results to compare the differences of microstructural properties between high fineness slag and normal fineness slag after the hydration process.Conducting compressive strength experiment and connect its result with microstructural experiment’s results in order to understand when high fineness slag adds into concrete how microstructural affect engineering properties
26
Hung, Shih-hsun, and 洪世勳. "Thermodynamic analysis on conformation change of polyethylene glycol during hydration process." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/t8w94c.
Full textAbstract:
碩士國立中央大學
化學工程與材料工程研究所
96
Polyethylene glycol (PEG) is linear and neutral polymer. The characteristic of low toxicity and preventing nonspecific adsorption of protein provides PEG extensive usage in biomaterials and biomedical application. The prevalent viewpoint to non-fouling phenomenon of PEG is due to the steric exclusion PEG produces in the solution as well as the hydrophilic chain of PEG. The hydration water structure around PEG molecule provides more energy barrier in the adsorption process of other solutes. In this study, we probe into the change of thermodynamic properties during the hydration process of PEG by ITC and modified segment-based NRTL model. The result shows the monomers of PEG tend to aggregate in the solution in order to reduce the water accessible surface area. When the molecular weight is over 500 (g/mole), PEG starts to fold because of entropy compensation. Besides, the hydrophilic of PEG segment decreases with the increasing of molecule weight for different factors. We also estimate the heat of dilution of PEG solution by modified segment-based NRTL model. For PEG-water binary system, although there is similar trend between predicted and experimental data, the accuracy is different by an order. For PEG-salt-water ternary system, we found it hard to predict the result by thermodynamic model.
27
Shin, Chun-Yuan, and 施淳元. "The Effect of Stratum Corneum Hydration on Transdermal Drug Delivery Process." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/50000971819813467592.
Full textAbstract:
碩士國立中興大學
化學工程學系所
98
Water not only serves as a solvent, but also is a chemical penetration enhancer in transdermal drug delivery system. Therefore, the hydration of skin is an important topic. In the study, we aim at obtaining a series of effective permeability coefficients of drugs, with a range of lipophilicity along with the corresponding drug release curves, which provide an important approach for the investigation of the effect of hydration on transdermal drug delivery. The main purpose of this study is to use a simple and accurate numerical model to fit the effective permeability coefficient for various drugs. as the precise quantification of effective permeability is obtained, attempts are made to elucidate the mechanism for the hydration of skin impacting the effective permeability of skin. And drugs of various lipophilicity(termed Ko/w) are investigated to study the correlation between lipophilicity of drug molecules and the hydration of the stratum corneum layer.
28
Phan, Duong Thuy. "Catalytic improvement of CO2 hydration relevant to the post combustion capture process." Thesis, 2015. http://hdl.handle.net/1959.13/1310465.
Full textAbstract:
Research Doctorate - Doctor of Philosophy (PhD)The increasing emissions of such greenhouse gases as carbon dioxide (CO₂) foster the need for the removal of CO₂ from gas streams, especially from coal-fired power stations. One of the common technologies of CO₂ Post Combustion Capture (PCC) is reversible chemical absorption using amine-based solvents. For PCC to be efficient, the rate of the absorption of CO₂ in aqueous solution has to be fast in order to minimise the spatial requirements of the absorber column. Therefore, the catalysis of CO₂ hydration/dehydration is of utmost interest. In this project, series of inorganic oxoanions and carbonic anhydrases were studied by stopped-flow spectrophotometry with the aim of elucidating their chemistry in the interaction with CO₂ and finding a good catalyst for PCC. Additionally, it is crucial to closely monitor the PCC process by developing on-line analyses. Fourier-transform infrared (FT-IR) spectroscopy is a promising spectroscopic tool for this purpose thanks to its robustness and ease of data interpretation. The second focus of this project is to investigate the feasibility of using FT-IR spectroscopy for on-line analysis for PCC application by monitoring the kinetics of the reaction of bicarbonate with MEA by this spectroscopy. The outcomes of this project would benefit the development of effective CO₂ capture facilities, contributing to the reduction of greenhouse gas emissions. The limitations in terms of time consumption and complexity of the traditional method to study an enzymatic system inspired the development of a novel kinetic procedure to analyse the efficiency of enzymatic catalysis, i.e. the Michaelis-Menten parameters. The principle of this method is that the kinetics of an enzymatically catalysed reaction is observed from the initial high substrate concentration until the substrate is entirely consumed. The course of the reaction process is followed via the solution pH changes. This approach is different from the integration method in which the determination of the substrate or product concentration is required, which is difficult. The new procedure has been applied to the study of urea hydrolysis by jack bean urease. Not only have the Michaelis constant and catalytic constant been determined with ease, the catalytic mechanism of urease was further clarified. This novel method is applicable to the study of many other enzymatic systems.
29
Zou, Bing-You, and 鄒秉佑. "Design and Control of a tert-Butyl Alcohol Hydration Process via Reactive Extraction Configuration." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/47871144712697540676.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
104
Crude oil is a non-renewable resource, The demand of crude oil continuously increases, as the global economic development. For the purpose of sustainable development and minimize production costs of the chemical industry, different types of chemical processes are developed. This study attempts to combine the reactor and the extraction process to reduce energy consumption and total annual cost. In the research, the reactive extraction in hydration of tert-butyl alcohol is demonstrated and compared with reactive distillation. The feed may contain impurity, like n-butene, so reactive extraction with n-butene is also demonstrated. The reactive extraction can achieve high conversion without energy. In constrain of liquid-liquid equilibrium, the higher cost of the separation section is required. The steady state simulation result shows the reaction extraction can save 26.0 % energy consumption and 16.1 % total annual cost, respectively. In process dynamics, the reactive extraction with n-butene is used to demonstrate. Since the reactive extraction column contains chemical reaction and liquid-liquid separation. Three inventory control loops (Inventory A~C) are studied to maintain stoicmetric balance, liquid-liquid equilibrium and both situations. In the quality control loop, using two temperature control loop in column C1 is better than one temperature control loop. The dynamic result shows that the best control structure is two temperature control loop in column C1 with inventory C.
30
WENG, REN-HUANG, and 翁仁滉. "Hydration mechanisms and physical properties of slag-cement hardened through dry-mix/steam-injection process." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/14805569612016377197.
Full text
31
Wang, Gwo-Tzong, and 王國宗. "Hydration Mechanisms and Strength Growth of Silica Fume-Cement dened through Dry-Mix/Steam-Injection Process." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/13771966365776518709.
Full text
32
Jong-Chang, Chiou, and 邱忠昌. "strength growth and hydration mechanisms of fly ash cement hardened through dry-mix/steam-injection process." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/19887272042210210583.
Full text
33
Chu, Yung-Chen, and 朱永成. "The effect of different hydration energy cation on organic compound chlorination during drinking water purification process." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/39506142676914389747.
Full textAbstract:
碩士國立中央大學
環境工程研究所
93
The effect of hydration energy cation on organic compound chlorination during drinking water purification process was studied using montmorillonite with five exchangeable cations(Ca, Mg, K, Na, Cs) as simulated suspended solid. The experiments were conducted adsorption of organic compounds on clays both in gas phase and in liquid phase. For the gas adsorption, the sorbates consisted of water and some polar organic compounds, and the sorbents are the clays with exchangeable cation. For the aqueous system, the different exchangeable cations on clay surface are regarded as catalytic center to investigate the relationship between the hydration energy of metal cation and the chlorinated reaction of organic compounds. The obtained results indicated that Ca-montmorillonite (Ca-mont) and K-montmorillnite (K-mont) were effective catalyzers as showing in good correlation between hydration energy and DBPs production. For all of the organic precursors, the DBPs produced were Ca-mont > K-mont, implying that the differences in hydration energy of cations could lead to the different hydration level on catalytic sites. The water solubilities of organic precursors represent the probability of the organic compounds to reach catalytic sites. However, chemical activities of organic compounds are a key point for the DBPs production. The results obtained from vapor-phase experiments show that the water adsorption has a strong correlation with the hydration energy of the clay surface cation. Our findings in this study imply that the hydration energy of cations on the clay surface can generate the different catalytic sites to change the disinfection by-products formation potential(DBPFP).
34
Yan, Jyh-Cherng, and 顏志成. "Strength Growth and Hydration Mechanisms of Various Fineness Slag-Cement Hardened througth Dry-Mix/Steam- Injection Process." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/48282464109021062790.
Full text
35
Ho, Van Dac. "Development of Next-Generation Construction Materials with Graphene Additives." Thesis, 2020. http://hdl.handle.net/2440/128468.
Full textAbstract:
The developments of ordinary Portland cement (OPC) composites and alkali-activated binder composites have attracted significant attention in the past decade. Different technologies have been proposed to address current drawbacks of these construction materials (e.g. low tensile strength, flexural strength, and brittleness), reduce the amount of cement consumption or replace OPC products for minimizing the environmental impact of construction materials. Among many additives explored to address these problems, graphene-based materials have emerged in the last few years as one of the most promising additives with many exciting results. However, it is still lacking the depth of understanding the influence of key parameters of graphene materials, such as dosages and sizes, on mechanical and durability properties of the composites, and enhancing mechanism of pristine graphene (PRG) in the cement matrix. Moreover, no study has been reported on the influence of graphene oxide (GO) additives on mechanical and durability properties of fly ash (FA)/ ground granulated blast furnace slag (GGBS) alkali-activated binder (AAB) composites prepared with natural sand (NS) or lead smelter slag (LSS) sand cured at ambient temperature. This thesis consists of a series of studies with the focus on addressing current research gaps and making a contribution to the development of next-generation construction materials using graphene additives. The first experimental study on the effect of the dosage of an ultra-large size (56μm) of PRG industrially manufactured by an electrochemical process on compressive and tensile strengths of cement-based mortars reveals that the addition of PRG to mortars improves their mechanical properties, with characteristic concentration dependence. The mortar with 0.07% PRG is identified as the optimal concentration, which provides 34.3% and 26.9% improvement in compressive and tensile strength at 28 days, respectively. However, with the further increases in PRG contents, the enhancement of mechanical properties of mortars is limited due to the impact of the van der Waals force on the sedimentation of PRG suspension. The second study focuses on the size effect of PRG on mechanical strengths of cement-based mortars by considering a variety of PRG sizes, such as 5μm, 43μm, 56μm, and 73μm at the optimal dosage of 0.07% PRG. The study reveals that the mechanical strengths of mortars at 7 and 28 days significantly depend on the sizes of PRG. The mixes with size 56μm and 73μm show a significant influence on both the compressive and tensile strengths of mortars. In contrast, the mix containing size 43μm exhibits a significant increase in tensile strengths only. There are no significant effects on either compressive or tensile strengths for the mix with size 5μm. The third study presents the proposed reinforcing mechanism and optimized dosage of PRG for enhancing mechanical properties of cement-based mortars. The results confirmed that the strengths of the mortars depend on PRG dosages. The size of PRG has a significant effect on the enhancement rate of the mechanical strengths of the mortars, whereas it does not have a significant influence on the optimized PRG dosage for the mechanical strengths of the cement-based mortars. The dosage at 0.07% PRG is identified as the optimized concentration of PRG for enhancing mechanical strengths. The reinforcing mechanism of PRG in the cement matrix highly depends on the surface area of PRG sheets. The fourth and fifth studies show the effect of the dosages, sizes, and densities of PRG as well as design mixes on mechanical and durability properties of cement-based mortars cured at short-term and long-term periods. The study reveals that the addition of PRG to mortars can enhance compressive, flexural, and tensile strengths of mortars at different curing ages. The 0.07% PRG is identified as the optimum dosage for enhancing the mechanical strengths of the mortars. Incorporating a small amount of PRG additives into the mortar can improve its durability, such as water absorptions, voids, sulphate expansion, and water penetration depths. The results of the mix containing PRG size 73μm show the best improvement in the mechanical and durability properties of the mortars, followed by that of size 20μm and then size 40μm. The last experimental study on the influence of GO additive on mechanical and durability properties of AAB mortars containing NS and LSS sand cured at ambient temperature reveals that the increase of GGBS% in AAB results in a significant increase in compressive and tensile strengths, and a decrease in flowability, water absorption and dry shrinkage of the mortars. The results also show that the mortars with 0.05% and 0.1% GO additives provide better mechanical and durability properties compared to the control mixes. The results generated from this thesis show great potential for using PRG and GO as additives in OPC and AAB composites to develop next-generation construction materials. They not only address the current drawbacks of OPC and AAB composites but also reduce the environmental impact of using OPC and NS.Thesis (Ph.D.) -- University of Adelaide, School of Civil, Environmental and Mining Engineering, 2020
36
Yu, Wen-Yi, and 余文儀. "Strength Growth and Steam-injection Process Model of Cement-sand Paste Hydratrion through Wet-Mix/steam-injection Process." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/70541947245523322201.
Full textAbstract:
碩士國立交通大學
土木工程學研究所
86
The proposed method is to replase some part of cement in the specimens with silica(Ottawa sand), By dint of the CaO and SiO2 of cement and silica being heat-reaction through high temperature steam-injection process, and that produced high-strength tobermorite. The testing variable includes: the percentage of silica, temperature(pressure), hydration duration and preset. Meanwhile, We gain the hydration degress and cement of Ca(OH)2 through the SEM and method of loss of ignition and compressive strength after hardening to understand hydration Mechanisms and strength growth. Because the Potland Concrete under high-temperature and high-pressure steam has the advantage of early-stage strength and dense-structure; and if there exists extra SiO2 under this catalysis condition, the original hydration produce will be improved, and its strength and durability will be higher. The silica added in cementsand paste just can serve as the source of SiO2, Hence, cement-sand paste through high-temperature and high-pressure steam-injection process. All cement-sand paste cubes(5cm) made by exposing wet mixes to 180℃ steams for 12 hours hydration duration and 2 hours preset developed strength greater than 1635kg/cm2.
37
Petticrew, Cassandra. "An investigation into the use of fluorinated hydrating agents in the desalination of industrial wastewater." Thesis, 2011. http://hdl.handle.net/10413/8986.
Full textAbstract:
Salts in solution should be removed by desalination techniques to prevent equipment fouling and
corrosion. Common desalination technologies are energy intensive such as Multi Stage Flash
(MSF) distillation which requires 14.5 J/m3 (Ribeiro. J, 1996) of energy. Desalination technologies
produce purified water and a concentrated salt solution, where the salt concentration is dependent
on the desalination technology used. This work investigates gas hydrate technology as a possible
desalination technology.
Hydrates are composed of guest molecules and host molecules. Guest molecules may be in the
form of a liquid or gas. During hydrate formation, host molecules, water, form a cage enclosing the
guest molecule. Common hydrate formers or guest molecules such as; methane, ethane, propane
and carbon dioxide are currently being investigated in literature, for use in gas hydrate desalination
technology. Common hydrate formers form hydrates at low temperatures; below 288 K and high
pressures; above 2 MPa. To increase the temperature and reduce the pressure at which gas hydrates
form, commercially available hydrofluorocarbon hydrate formers such as R14, R32, R116, R134a,
R152a, R218, R404a, R407c, R410a and R507 are preliminarily investigated in this work.
The criteria for choosing the most suitable fluorine-based formers require the former to be:
environmentally acceptable where it is approved by the Montreal Protocol; non-toxic where it has a
low acute toxicity; non-flammable; chemically stable; a structure II hydrate to simplify the washing
process; available in commercial quantities; low cost in comparison to other hydrate formers;
compatible with standard materials and contain a high critical point for a large heat of vaporisation
(McCormack and Andersen, 1995). Taking all these criteria into account, R134a was chosen for
further investigation as a possible hydrate former.
In this work, hydrate-liquid-vapour phase equilibrium measurements are conducted using the
isochoric method with a static high pressure stainless steel equilibrium cell. The Combined
Standard Uncertainty for the 0-1 MPa pressure transducer, 0-10 MPa pressure transducer and the
Pt100 temperature probes are ±0.64 MPa, ±5.00 MPa and ±0.09 K respectively. Vapour pressure
measurements for Hydrofluoropropyleneoxide, CO2, R22 and R134a were measured to verify the
pressure and temperature calibrations. Hydrate test systems for R22 (1) + water (2) and R134a (1)
+ water (2) were measured to verify calibrations, equipment and procedures. New systems
measured included R134a (1) + water (2) + {5wt%, 10wt% or 15wt%} NaCl (3).
For the system R134 (1) + water (2) at 281 K the dissociation pressure is 0.269 MPa. However,
addition of NaCl to the system resulted in a shift of the HVL equilibrium phase boundary to lower
temperatures or higher pressures. The average shift in temperature between the system R134a (1) +
water (2) containing no salt and the systems containing {5, 10 and 15} wt% NaCl are -1.9K, -4.8K
and -8.1K respectively.
In this work, the measured systems were modelled using two methods of approach. The first
method is where hydrofluorocarbon hydrate former solubility is included, (Parrish et al., 1972) and
the second is where hydrofluorocarbon hydrate former solubility is ignored, (Eslamimanesh et al.,
2011). From these models, it is found that hydrofluorocarbon solubility could not be neglected.
In this work, the hydrate phase was modelled using modifications of the van der Waals and
Platteeuw model, (Parrish et al., 1972). The liquid and vapour phases are modelled using the Peng-
Robinson equation of state with classical mixing rules (Peng, 1976). The electrolyte component is
modelled using the Aasberg-Peterson model (Aasberg-Petersen et al., 1991) modified by Tohidi
(Tohidi et al., 1995). The percent absolute average deviation (%AAD) for the systems, which
includes solubility, is 0.41 for R22 (1) + water (2) and 0.33 for R134a (1) + water (2). For the
system R134a (1) + water (2) + {5 wt%, 10 wt% or 15 wt%} NaCl (3) the % AAD is 5.14.
Using the hydrate former, R134a, is insufficient to ensure gas hydrate technology is competitive
with other desalination technologies. Hydrate dissociation temperature should be increased and
pressure decreased further to ambient conditions. As evident in literature, promoters, such as
cyclopentane, are recommended to be added to the system to shift the HLV equilibrium phase
boundary as close to ambient conditions as possible.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.