Thesis (Ph. D.) --Memorial University of Newfoundland, 1997. / Restricted until November 1998. Bibliography: leaves 264-281.

Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007. / Kohl, Paul, Committee Chair ; Bottomley, Lawrence, Committee Member ; Eckert, Charles, Committee Member ; Fuller, Tom, Committee Member ; Teja, Amyn, Committee Member.

Thesis (Ph.D.)--Ohio University, June, 2005. / Title from PDF t.p. Includes bibliographical references (p. 89-92)

Στην παρούσα μεταπτυχιακή εργασία μελετήθηκε ο τρόπος κατασκευής νανοσωλήνων TiO2 .Επίσης ερευνήθηκαν κάποιοι παράμετροι που επηρεάζουν την γεωμετρία τους όπως είναι η τάση, ο χρόνος και οι ηλεκτρολύτες. Αρχικά στο πρώτο κεφάλαιο αναλύθηκε εκτενέστερα η νανοτεχνολογία η οποία σχετίζεται με την κατανόηση και τον έλεγχο της ύλης, σε διαστάσεις 1 έως 100 nm. Στη συνέχεια πραγματοποιήθηκε μια πλήρη ταξινόμηση των νανοϋλικών καθώς και η εφαρμογή τους στην αεροναυπηγική στην ιατρική και ως ηλιακές κυψελίδες. Στο δεύτερο κεφάλαιο γίνεται αναφορά στην ηλεκτροχημική ανοδίωση, μια από τις πιο γνωστές μεθόδους για την σύνδεση και παραγωγή νανοσωλήνων, αλλά και για την κατασκευή νάνο-επιφανειών. Επιπλέον αναφέρονται όλα τα συστατικά που χρησιμοποιούνται στη μέθοδο αυτή αλλά και όσα πρέπει να γνωρίζουμε για τους ηλεκτρολύτες. Στη συγκεκριμένη διπλωματική εργασία το υλικό με το οποίο ασχοληθήκαμε, μελετήσαμε και επεξεργαστήκαμε ήταν το τιτάνιο, το οποίο αναλύεται στο τρίτο κεφάλαιο. Το Τιτάνιο είναι ένα παραδοσιακό μέταλλο με πολύ καλές ιδιότητες μηχανικές αλλά και φυσικές έχοντας αρκετές εφαρμογές σε πάρα πολλούς τομείς όπως στην αυτοκινητοβιομηχανία, στην ιατρική, στη χημική βιομηχανία και στη ναυπηγική. Έπειτα στο τέταρτο κεφάλαιο γίνεται αναφορά στις κατανομές που χρησιμοποιήσαμε στην διπλωματική αυτή όπως είναι η κανονική κατανομή ή κατανομή Gauss και στην Weibull κατανομή. Οι κατανομές αυτές ήταν το εργαλείο για να μπορέσουμε να ερμηνεύσουμε αλλά και να κατανοήσουμε πλήρως τα αποτελέσματα μας. Στο κεφάλαιο πέντε παρουσιάζεται αναλυτικά η διαδικασία διεξαγωγής των πειραμάτων μας, αλλά και πλήρης ανάλυση και σχολιασμός των αποτελεσμάτων. Τέλος στο κεφάλαιο έξι αναλύονται τα συμπεράσματα που προέκυψαν από τα πειράματα για την παρούσα διπλωματική εργασία. / In the present master thesis the construction route of TiO2 nanotubes were studied. A variety of parameters, that affect their geometry such as voltage, time and electrolytes. was investigated. Ιn the first Chapter become report in the nanotechnology which is related to the conception and control of material in dimension 1 to 100nm. Then, a complete categorization of nano-materials is carried out. Also we talked about the applications of these to the field of aeronautical, medicine and solar cells. In the second chapter we analysed in detail the electrochemical anodizing, one of the most well-known procedures for the connection and production of nanotubes but also for the construction of nano-surfaces. Furthermore, all the materials used for this method are mentioned as well as everything we need to know about electrolytes. In the present master thesis the material which we worked on, studied and processed was titanium which is analyzed in the third chapter. Titanium is a traditional metal having excellent mechanical and physical properties that make it useful in many applications such as car industry, medicine, chemical industry and shipbuilding. In the fourth chapter there is a reference to the master thesis used during the dissertation such as the normal distribution or Gaussian distribution and Weibull distribution. These distributions were considered the tool that enabled us to explain and fully understand our results. Chapter five presents the analytical procedure to conduct our experiments and thorough analysis and discussion of our results. Finally, in chapter six the results derived from the experiments in the present master thesis are analyzed.

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The technology employed by human beings for the generation, storage and usage of energy is presently undergoing the fastest and most profound change since the industrial revolution. The changes in the generation and usage of energy necessitate the development of new methods of energy storage. In these systems, electrochemical energy storage will play a crucial role and to this end new electrolytes need to be explored to complement these changes. One such class of liquids is ionic liquids, a class of salts that are molten at room temperature. These liquids have a broad applicability to batteries and supercapacitors. This thesis details work where molecular dynamics simulations have been used to explore the nanostructure of ionic liquids and their mixtures with various molecular solvents at simplistic electrodes. The thesis has two broad sections. The first is covered in Chapter 3, and explores the nanostructure of ionic liquid propylene carbonate solutions, developing a framework through which these nanostructures can be understood. The section concludes that the increasing dilution of ionic liquids decreases the surface charge at which the characteristic ionic liquid oscillatory interfacial structure gives way to a different structure featuring monotonic charge decay. The behaviour of ionic liquids at interfaces is found to be correlated to ion size and type, as well as concentration. A wide divergence in the observed behaviour is shown at positive and negative electrodes due to the asymmetry of propylene carbonate. The second section, consisting of two chapters, explores the interfacial nanostructure of solvate ionic liquids using two different boundary conditions to model the electrode. This work is the first simulation of solvate ionic liquids at electrified interfaces. This section will explore the effect of electrode model on the behaviour of these ionic liquids at the electrode. Chapter 4 uses a fixed charge electrode, whereas Chapter 5 uses one with a fixed potential. The section concludes that regardless of electrode model, the idealised portrait of a solvate ionic liquid - one where the liquid behaves exactly as an aprotic ionic liquid - is not applicable. In Chapter 4's exploration of fixed charged electrodes, the formation of 2 glyme to lithium complexes contradicts the idealised portrait of the liquid. A different change is observed in Chapter 5's exploration of fixed potential electrodes, with both lithium glyme and lithium anion clusters forming at the interface. The key difference between the two studies is that lithium does not coordinate to the electrode in the fixed charge simulations, while in the fixed potential case it does. At the end of Chapter 5 the results are compared against experimental data, with the efficacy of the two models discussed. The aim of both studies is to look at the nanostructure of ionic liquids, when the symmetry between co-ion and cation repulsion - and related effects - is broken by the presence of a non ionic constituent in the liquid.

abstract: Plastic crystals as a class are of much interest in applications as solid state electrolytes for electrochemical energy conversion devices. A subclass exhibit very high protonic conductivity and its members have been investigated as possible fuel cell electrolytes, as first demonstrated by Haile’s group in 2001 with CsHSO4. To date these have been inorganic compounds with tetrahedral oxyanions carrying one or more protons, charge-balanced by large alkali cations. Above the rotator phase transition, the HXO4- anions re-orient at a rate dependent on temperature while the centers of mass remain ordered. The transition is accompanied by a conductivity "jump" (as much as four orders of magnitude, to ~ 10 mScm-1 in the now-classic case of CsHSO4) due to mobile protons. These superprotonic plastic crystals bring a “true solid state” alternative to polymer electrolytes, operating at mild temperatures (150-200ºC) without the requirement of humidification. This work describes a new class of solid acids based on silicon, which are of general interest. Its members have extraordinary conductivities, as high as 21.5 mS/cm at room temperature, orders of magnitude above any previous reported case. Three fuel cells are demonstrated, delivering current densities as high as 225 mA/cm2 at short-circuit at 130ºC in one example and 640 mA/cm2 at 87ºC in another. The new compounds are insoluble in water, and their remarkably high conductivities over a wide temperature range allow for lower temperature operations, thus reducing the risk of hydrogen sulfide formation and dehydration reactions. Additionally, plastic crystals have highly advantageous properties that permit their application as solid state electrolytes in lithium batteries. So far only doped materials have been presented. This work presents for the first time non-doped plastic crystals in which the lithium ions are integral part of the structure, as a solid state electrolyte. The new electrolytes have conductivities of 3 to 10 mS/cm at room temperature, and in one example maintain a highly conductive state at temperatures as low as -30oC. The malleability of the materials and single ion conducting properties make these materials highly interesting candidates as a novel class of solid state lithium conductors. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2016

Made available in DSpace on 2014-06-11T19:23:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-02Bitstream added on 2014-06-13T20:51:03Z : No. of bitstreams: 1 martinezpadua_pp_me_jabo.pdf: 231585 bytes, checksum: 719d0da0e793ed4ad3d44959f5accf9a (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Os rins desempenham papel fundamental no balanço de água e eletrólitos. Na doença renal crônica (DRC) a manutenção da homeostase de água e sódio é o primeiro problema a ser contornado pelo organismo e com o agravamento das lesões renais surgem outros problemas graves relacionados à homeostase de cálcio e fósforo. O presente estudo tem por escopo avaliar a excreção renal de cálcio, fósforo, sódio e potássio, e o perfil sérico destes eletrólitos em cães normais e em cães com DRC naturalmente adquirida. Foram avaliados três grupos de cães adultos, machos ou fêmeas, de raças variadas. Animais normais compuseram o grupo controle (G1) e os cães com DRC foram distribuídos em dois grupos de acordo com os estágios de comprometimento da função renal (G2 e G3, respectivamente, estágios 1-2 e estágios 3-4, descritos pela IRIS 2006 staging CKD). Os cães do G3 apresentaram aumento das concentrações séricas de cálcio ionizado e fósforo, além de diminuição da concentração sérica de sódio. Quanto à excreção renal dos eletrólitos analisados, os animais dos grupos G1 e G2 apresentaram diminuição de carga filtrada e aumento de excreção fracionada, mas as excreções urinárias não variaram significativamente. Os resultados são indicativos de que os rins de cães com DRC podem manter a excreção urinária dos eletrólitos em valores semelhantes aos dos normais. O mecanismo envolve aumento da excreção fracionada à medida em que haja diminuição da filtração glomerular. Esse processo de compensação, entretanto, pode perder a eficiência nos estágios mais avançados da enfermidade no que se refere à manutenção das concentrações séricas de fósforo e sódio. / The kidneys play a fundamental role in the balance of water and electrolytes. In chronic kidney disease (CKD), the first problem to be solved by the organism is to maintain water and sodium homeostasis and, with the worsening of the renal injuries, other severe problems related to the calcium and phosphorus homeostasis emerge. The present study has as a purpose to evaluate the renal excretion and serum profile of calcium, phosphorus, sodium and potassium in healthy dogs and in dogs with naturally acquired CKD. Three groups of adult male and female dogs of varied breeds were evaluated. Normal animals were in the control group (G1) and the CKD dogs were distributed in two groups in accordance with the stage of renal function impairment (G2 e G3, respectively, stages 1-2 and stages 3-4, proposed by IRIS 2006 staging CKD). The G3 dogs showed increased serum levels of ionized calcium and phosphorus, in addition to the reduction of sodium level. Regarding the renal excretion of the analyzed electrolytes, G1 and G2 groups of animals showed a decrease of filtered load and increase of fractional excretion, yet there were no significant variations on the urinary excretions. The results suggest that the kidneys of the CKD dogs can maintain similar values of electrolytes urinary excretion as the normal dogs do. The mechanism involves an increase of fractional excretion while glomerular filtration decreases. This compensation process, however, can lose its efficiency in the later stages of the disease, in relation to the maintenance of phosphorus and sodium serum levels.

Made available in DSpace on 2014-06-11T19:23:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-16Bitstream added on 2014-06-13T18:51:21Z : No. of bitstreams: 1 jeremias_jt_me_jabo.pdf: 358762 bytes, checksum: 340c662a9f286424e15dcb1907d5b14b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A composição mineral da dieta influencia as características da urina de gatos, estando envolvida no desenvolvimento e prevenção de urolitíases. O excesso de bases (EB) do alimento possui alta correlação com o pH urinário de gatos. Este pode ser calculado a partir da determinação da composição de macroelementos ou de aminoácidos sulfurados contidos na dieta. Em um primeiro estudo comparou-se fórmulas publicadas para estimar o EB do alimento e o pH urinário de gatos, avaliando a influência do enxofre e dos aminoácidos sulfurados sobre os cálculos, e verificou a relação entre o EB do alimento e parâmetros hemogasométricos. Em outro estudo foram avaliados os efeitos da adição de sais aniônicos acidificantes e de sais catiônicos alcalinizantes em dietas para felinos, com o objetivo de se validar as equações de estimação do pH urinário desenvolvidas no estudo anterior, demonstrar a eficácia desses sais, bem como verificar possíveis perturbações no equilíbrio ácido-básico dos animais decorrentes destas modificações na composição da dieta. Os gatos permaneceram em gaiolas metabólicas durante sete dias de adaptação à dieta, seguidos por três dias de coleta total de urina. Durante a coleta, a urina produzida em cada período de 24 horas teve aferida seu volume, densidade e pH. O equilíbrio ácido-básico foi estudado pela hemogasometria de sangue venoso. Amostras de sangue foram coletadas às 8:00hs (antes do fornecimento do alimento) e 6 horas depois do fornecimento, após 10 dias de adaptação ao alimento. No primeiro estudo o pH urinário variou entre 5,83±0,09 e 7,74±0,13. O EBS entre –185 e 309 mEq/kg MS e EBaa entre -49 e 377 mEq/kg MS. A diferença média de -115 mEq/kg entre EBS e EBaa foi observada. O pH urinário apresentou alta correlação com o EBS (r=0,95; p<0.0001) e EBaa (r=0,86; p<0.0001)... / Food mineral composition influences the characteristics of cat’s urine and is involved in the development and prevention of urolithiasis. Food base excess (BE) has a high correlation with cat urinary pH. BE can be calculated utilizing only macroelements or using sulfur amino acids (methionine and cistine) instead of total sulfur. In the first chapter compared published formulas to estimate food BE and urinary pH of cats, evaluated the influence of total sulfur and sulfur amino acids on BE calculations, and verified the relationship between food BE with cat blood gases analysis. In other chapter, effects of acidifying and alkalizing additives on cats food were evaluated, so that: 1. the urinary pH prediction equations developed on chapter 2 could be validated, 2. mineral salt efficacy could be demonstrated, 3. potential acid base alterations caused by the additives used on the cat’s food could be verified. Cats were housed in metabolic cages and fed during a seven days adaptation phase followed by three days of total urine collection. Urine was collected in plastic bottles conserved in ice under the cage funnel. Each 24-h of produced urine were pooled by cat and analyzed for density, volume and pH. Cat’s acidbasic status was studied by blood gas analysis of venous blood. Blood samples were collected at 8:00h (pre feeding) and 6 hours after meal, after 10-days of food adaptation. In the first chapter pH of cats varied in the interval of 5.83±0.13 (mean±SD) and 7.74±0.12. Food BEs varied between –185 and 309 mmol/kg DM, and food BEaa between -49 and 377 mmol/kg DM. A mean difference of -115 mmol/kg between EB1 and EB2 was observed Urine pH has high correlations with food BEs (r=0.95; p<0.0001) and BEaa (r=0.86; p<0.0001). In the second chapter Alkalizing additives: urinary pH of cats varied in the interval of 5,60±0,07 a 6,15±0,06 (p<0,0005)... (Complete abstract click electronic access below)

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