Acid treatments have predominantly been conducted using HCl for its availability, high rock dissolving power and soluble reaction products. At high temperatures, rapid spending of the acid with carbonates prevents deeper penetration distance into the formations. Alternative fluids such as acetic and formic acid have lent themselves to retarded reaction rates, low corrosivity and reduced tendency to form acid/oil sludge in asphaltene-rich crudes but for high reaction rate problems. Chelating agents, with the added advantage of complexing with alkali-earth metals in carbonates to form water-soluble products that are thermally stable at high temperature, have been introduced as stimulation fluids. Glutamic acid diacetic acid (GLDA) ethylenediaminetetraacetic acid (EDTA) and hydroxyethylenediaminetriacetic acid (HEDTA) are aminopolycarboxylic acids that were studied. To predict the spending of chelating agents relative to simple organic acids at temperatures between 150 and 250˚F, the chemical kinetics of dolomite dissolution in these acid solutions were investigated over different reaction conditions in a rotating disk apparatus. Samples of the reacted acids from the reactor were collected and then analyzed with inductively coupled plasma (ICP). Analyses of the experimental data were carried out to determine kinetic parameters of the heterogeneous reactions needed for matrix stimulation of dolomitic reservoirs. Experimental results indicated that dolomite dissolution rates increased in all the acid solutions as the disk rotational speeds increased at 150, 200, and 250˚F. The dissolution of dolomite in 0.886 M GLDA was found to be surface-reaction limited at lower temperatures and mass-transfer limited at highest temperature. GLDA with the lowest reaction rates and relative diffusion coefficient demonstrated retardation before spending with deeper penetration capability for productivity and injectivity improvement.

[Truncated abstract] There have been few studies into the effects of rehabilitation following lumbar microdiscectomy and consequently little evidence of its effect, if any, on outcome. Most studies cited fall into one of two categories: research involving a spinal surgery procedure without rehabilitation, or research involving spinal surgery with a nonspecific generic 'rehabilitation' or 'physical therapy'. In an era of evidence based medicine the efficacy of specific rehabilitation protocols following defined lumbar spine surgical procedures needs to be established for surgeons, therapists and patients to have confidence that the rehabilitation is appropriate and effective. The study was proposed to investigate the outcome of a specific and novel rehabilitation protocol commenced immediately after lumbar microdiscectomy. Data collected from the research cohort were compared to data collected from a contrast group who underwent standard rehabilitation at a distant site. A retrospective study (Phase One) was carried out with a cohort of post-operative microdiscectomy patients between February 2000 and December 2002. The outcome of surgery followed by the rehabilitation protocol was assessed using validated outcome instruments. A contrast or control group was not included. After reviewing the data limitations with the design and implementation of the study were identified. A prospective study (Phase Two) was proposed and changes made in the principal outcome measure used, in the demographic data to be retrieved, the addition of pain scales, and in the exclusion of compensable patients. A contrast group was included for the prospective study. ... The study group commenced exercise and posture correction the day following surgery. There were restrictions placed on activity involving bending. The contrast group followed the advice of the surgeon in Queensland and attended rehabilitation at local physiotherapy facilities. Both groups were followed for 12 months using outcome instruments. Strict comparison between WA and QLD cohorts were limited due to sample size, however trends were observed. Data of the prospective study showed that there was greater reduction in back pain with the early rehabilitation protocol (P<.0001) compared to standard rehabilitation (P=.09), while there was no difference between groups in leg pain. There was a significant improvement in the level of functional disability between time-points for the WA cohort, and overall change from pre-operative RMQ measures to 12 months in both groups were statistically significant. The WA group was less reliant on pain medication and was more satisfied with the results of their surgery. The primary hypothesis of this study that there would be a difference in outcome following lumbar microdiscectomy in patients who receive early specific rehabilitation compared to those who receive standard rehabilitation at another centre, was supported in both primary and secondary outcome data. The key finding of this study was that commencing the early exercise protocol resulted in significantly less back pain over the 12 month time period of the study. Other major findings were that the WA cohort demonstrated significant improvement in function at all time-points and between all time-points except six to 12 months, took less pain medication and were more satisfied with the outcome of their surgery than the QLD cohort.

Bibliography: leaves 102-116. / 116, [43] leaves, [51] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Analyses the characteristics and relative incidence of annular defects in the human lumbar spine and investigates their role in the pathogenesis of invertebral disc degeneration. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 1992

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.

Στην παρούσα διπλωματική υλοποιήθηκε η σχεδίαση και υλοποίηση ασφαλούς υπηρεσίας με χρήση ελλειπτικής κρυπτογραφίας. Τα κρυπτογραφικά συστήματα που βασίζονται στις ελλειπτικές καμπύλες αποτελούν ένα πολύ σημαντικό κομμάτι της κρυπτογραφίας δημόσιου κλειδιού και τα τελευταία χρόνια όλο και περισσότεροι επιστήμονες ασχολούνται με τη μελέτη τους. Το πλεονέκτημα των συστημάτων αυτών σε σχέση με τα συμβατικά κρυπτογραφικά συστήματα είναι ότι χρησιμοποιούν μικρότερες παραμέτρους και κλειδιά, προσφέροντας τα ίδια επίπεδα ασφάλειας. Σχετικά με το πρόβλημα της προστασίας ευαίσθητων δεδομένων σκληρού δίσκου ή άλλου αποθηκευτικού μέσου διευθυνσιοδοτούμενου κατά τομείς (sector-adressed storage media), χρησιμοποιείται η τεχνική της κρυπτογράφησης δίσκου (disk encryption). Ορισμένα από τα υπεύθυνα για την υλοποίηση της κρυπτογράφησης λογισμικά (disk encryption software) χρησιμοποιούν την μέθοδο κρυπτογράφησης σε πραγματικό χρόνο (on-the-fly/real-time encryption). Ο όρος on-the-fly έγκειται στο γεγονός ότι τα αρχεία γίνονται προσβάσιμα αμέσως μόλις προσφερθεί το κλειδί κρυπτογράφησης (encryption key) όλο το διαμέρισμα (volume) «προσαρτάται» (mounted) σαν να ήταν ένας φυσικός δίσκος κάνοντας τα αρχεία να «φαίνονται» αποκρυπτογραφημένα. Στην πλαίσιο αυτό τοποθετείται ο σκοπός του ερευνητικού μέρους της παρούσας εργασίας, που εντοπίζεται το ερώτημα της προσαρμογής βιβλιοθηκών που υλοποιούν κρυπτογραφία ελλειπτικών καμπυλών σε λογισμικό ικανό να κρυπτογραφεί «on the fly» φακέλους αρχείων και κατ΄ επέκταση σκληρούς δίσκους / -

Ce travail est consacré à l’analyse expérimentale et numérique de l’essai normalisé de disque à rupture utilisé pour la sélection des matériaux métalliques sensibles à l’hydrogène et vise notamment à évaluer la potentielle extension de l’essai à des pressions plus élevées. L’étude a porté sur un acier AISI 4135 constitutif des bouteilles de stockage d’hydrogène gazeux. Des essais de disques réalisés sous He et sous H₂ ont permis d’étudier l’influence de différents paramètres sur les pressions de rupture et de disposer de courbes flèche-pression expérimentales.La réponse de l’essai pour des pressions supérieures au domaine d’usage actuel a été étudiée avec des disques de différentes épaisseurs. La caractérisation par MEB-EBSD de disques rompus ou fissurés a permis d’observer la fissuration à différentes échelles dans la microstructure bainitique. La simulation par éléments finis de l’essai de disque a permis d’analyser l’influence de différents paramètres sur la distribution des champs mécaniques dans le disque et a conduit à une confrontation satisfaisante avec les résultats expérimentaux. Les pressions de rupture sous He ont été obtenues par une simulation d’endommagement ductile, et les pressions de rupture sous H₂ ont été décrites à l’aide d’éléments cohésifs. Les distributions d’hydrogène diffusif et piégé dans le matériau au cours de l’essai de disque ont été obtenues par la prise en compte de la diffusion assistée par la pression hydrostatique et de l’évolution du piégeage avec la déformation plastique.L’extension de la simulation à l’échelle du polycristal ouvre la voie à des critères de fragilisation tenant compte des hétérogénéités microstructurales. / This work focused on the experimental and numerical analysis of the normalized disk pressure test used to select metallic materials hydrogen sensitive and particularly aimed to evaluate the potential extension of the test to higher pressures. The study focused on an AISI 4135 steel, which composed hydrogen gas storage vessels. Disk pressure tests had been leading under helium and hydrogen gas in order to study the influence of some parameters on failure pressures and to obtain experimental deflection-pressure curves. The response of the test for pressures higher than in the usual domain of specifications was studied for different disk thickness. SEM-EBSD characterization of failed or cracked disks allowed examining cracks at different scales in the bainitic microstructure. Finite element simulations of disk pressure test permitted to analyze the influence of different parameters on mechanical field distributions in the disk and led to a satisfying comparison with experimental results. Helium failure pressures were obtained by a ductile damage computation ; and hydrogen failure pressures were described thanks to a cohesive elements model. Distributions of diffusive and trapped hydrogen in the material during a disk pressure test were obtained considering hydrogen diffusion is assisted by the hydrostatic pressure and the evolution of trapping with strain. Extension of the simulation at polycrystalline scale open the way to embrittlement index ; taking into account microstructural heterogeneities.

Resumo: A produção de beta-lactamase de espectro estendido (ESBL) em membros da família Enterobacteriaceae pode conferir resistência a cefalosporinas de amploespectro, aztreonam e penicilinas. Devido a esse fenômeno, a detecção exata dos produtores de ESBL é essencial para a seleção apropriada da antibioticoterapia. Para detectar a produção de beta-lactamase de espectro estendido (ESBL) em bacilos Gram-negativos, foi usado um teste de triagem com os discos de aztreonam (ATM), ceftazidima (CAZ), cefotaxima (CTX) e ceftriaxona (CRO) sobre 300 cepas, das quais trinta e cinco eram suspeitas da presença de ESBL. A produção de ESBL foi demonstrada por três métodos fenotípicos confirmatórios de fácil utilização. Os três testes fenotípicos para confirmar a produção de ESBL incluíram o teste do sinergismo (double disk), E-test? ESBL e disco combinado. Os discos utilizados no teste do sinergismo e do disco combinado foram: aztreonam (30?g-ATM), cefotaxima (30?g-CTX), ceftazidima (30?g-CAZ), cefpodoxima (10?g-CPD) ceftriaxone (30?g-CRO) e amoxicilina+ácido clavulânico(30?g-AMC), cefotaxima+ácido clavulânico (30?g-10?g), ceftazidima+ácido clavulânico (30?g- 10?g), cefpodoxima+ácido clavulânico (10?g-1? g). Para E-test foram utilizadas fitas contendo as cefalosporinas: ceftazidima versus ceftazidima/ácido clavulânico; cefotaxima versus cefotaxima/ácido clavulânico. Os testes fenotípicos confirmaram a presença de ESBL em cinco cepas de enterobactérias (1,66%). Todos os métodos são de fácil execução, contudo o método do Etest requer experiência para interpretar os resultados. Os três testes oferecem uma solução viável para confirmar a produção de ESBL no laboratório clínico. / Abstract: The production of extended spectrum beta-lactamase (ESBL) in the members of the family Enterobacteriaceae can check resistance to cephalosporins of extended-spectrum, aztreonam and penicilins. Due to this phenomenon, the exact detection of the producers of ESBL are essential for the appropriate selection of antimicrobial therapy. To detect the production of extended spectrum beta-lactamase (ESBL) in Gram-negative bacilli, a test of screening was used with the discs of aztreonam (ATM), ceftazidime (CAZ), cefotaxime (CTX) e ceftriaxone (CRO) in 300 strains, of which thirty-five were suspicious of the presence of ESBL. The production of ESBL was demonstrated by three phenotypic methods confirmed of easy utilization. The three phenotypic tests to confirm the production of ESBL included the test of sinergy (double disk), E-test? ESBL and combination disk. The disks used on the test sinergy and the combination disk were: aztreonam (30?g-ATM), cefotaxime (30?g-CTX), ceftazidime (30?g-CAZ), cefpodoxime (10?g-CPD) ceftriaxone (30?g- CRO) e amoxicillin+clavulanic acid (30?g-AMC), cefotaxime+clavulanic acid (30?g- 10? g), ceftazidime+clavulanic acid (30?g-10? g), cefpodoxime+clavulanic acid (10?g- 1? g). For E-test, were utilized strips containing the cephalosporins: ceftazidime and ceftazidime/clavulanic acid; cefotaxime and cefotaxime/clavulanic acid. The phenotypic tests confirmed the presence of ESBL in five strains Enterobacteriaceae (1,66%). All of the methods are of easy execution; however, the method of Etest requires experiment to interpret the results. The three tests offer a viable solution to confirm the production of ESBL on a clinic laboratory. / Orientador: Elisabeth Loshchagin Pizzolitto / Coorientador: Antonio Carlos Pizzolitto / Banca: Wilton Rogério Lustri / Banca: Izabel Yoko Ito / Mestre

Neste trabalho é realizada a concepção, projeto, construção e ensaio de turbinas de múltiplos discos para a verificação dos principais parâmetros e metodologias utilizadas para o projeto e análise do equipamento, além de estudar formas de otimização do equipamento. Assim, uma turbina de múltiplos discos é construída e testada com diferentes configurações de rotores, em uma bancada experimental construída e dimensionada especialmente para esse fim, além da implementação dos métodos analíticos pesquisados no software Engineering Equation Solver (EES). Assim, uma comparação entre os resultados experimentais obtidos por Rice e os modelos de analíticos disponíveis, mostra que o modelo do fator de atrito (FA) é o que melhor representa a operação do equipamento, além de ser o mais versátil dos métodos testados, permitindo que a turbina seja dimensionada e otimizada para várias configurações de construção. Já os resultados experimentais obtidos com um dos protótipos de turbina construído e operado com ar comprimido, mostram que, com modificações simples da geometria, configuração e acabamento superficial dos discos que compõem o rotor, é possível aumentar a eficiência isentrópica em até 35% em relação a turbina padrão montada com a configuração padrão de rotor (discos lisos), sem acarretar prejuízo em alguns dos principais benefícios da utilização deste tipo de equipamento. Os resultados experimentais obtidos mostram também que a eficiência diminui significativamente com o aumento da folga entre o raio externo do rotor e a parte interna da carcaça. / This work is performed conception, design, construction and testing of multiple-disks turbines (MDTs) for the verification of key parameters and methodologies used for the design and analysis of machine as well as consider ways to equipment optimization. Thus, a multiple-disk turbine is constructed and tested with different impeller configurations, in a test rig especially constructed and dimensioned for this purpose, besides the implementation of the analytical methods in software Engineering Equation Solver (ESS). Thus, a comparison between the experimental results obtained by Rice and analytical models available, shows that the friction factor model (FF) is what best represents the operation of the equipment, and is the most versatile of the tested methods, allowing the turbine is sized and optimized for various building configurations. Since the experimental results obtained with one of the turbine prototypes built and operated with compressed air, show that with simple modifications of geometry, configuration and surface finish of the disks that make up the rotor, it is possible to increase the isentropic efficiency by up to 35% compared the standard turbine rotor mounted with the default configuration (flat disks), without causing damage in some of the major benefits of using this type of equipment. The experimental results also show that efficiency decreases significantly with increasing clearance between the outer radius of the rotor and the internal part of the housing.

CAMPOS, Othon Souto. Estudo Mecanístico da Eletrodeposição de Cádmio em Meio de Sulfato Ácido. 2011. 46 f. Dissertação (Mestrado em química)- Universidade Federal do Ceará, Fortaleza-CE, 2011. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-06-02T19:41:14Z No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-07-20T20:01:55Z (GMT) No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) / Made available in DSpace on 2016-07-20T20:01:55Z (GMT). No. of bitstreams: 1 2011_dis_oscampos.pdf: 938891 bytes, checksum: 170c80aaa846defc16b0b360c53792fb (MD5) Previous issue date: 2011 / This work describes a mechanistical proposition for cadmium electrodeposition in acid sulfate medium on platinum substrate using electrochemical techniques. The cadmium electrodeposition studies were carried in sodium sulfate 1 mol L–1 medium containing cadmium sulfate 10–2 mol L–1, which the pH of the solutions were adjusted with analytical grade sulfuric acid. The pH interval of the work solutions were ranged between 1 and 3. In all studied medium, the potentiostatic polarization curves showed a diffusional plateau which obeys the Levich equation. The interfacial pH studies showed the influence of acid–base equilibrium of bisulfate ion with the formation of a coordination compound Cd(HSO4)+ in platinum electrode. It is proposed that the cadmium ion associated in acid–base equilibrium of bisulfate ion, deposits as cadmium bisulfate at an irreversible step, and followed by a reversible metallic deposition of cadmium with the leaving of bisulfate ion, and this step is slower than the first one. Then, a mathematical model was calculated for the mechanism proposed, and qualitative studies were carried regarding to the polarization curve and electrochemical impedance spectroscopy behavior. / Este trabalho descreve uma proposição mecanística para a deposição de cádmio em meio de sulfato ácido sobre substrato de platina utilizando técnicas eletroquímicas. Os estudos de eletrodeposição de cádmio foram feitas em meio de sulfato de sódio 1 mol L–1 contendo 10–2 mol L–1 de sulfato de cádmio, em que o pH das soluções foi ajustado com ácido sulfúrico PA. O intervalo de pH das soluções de trabalho foi variado entre 1 e 3. Em todos os meios estudados, as curvas de polarização potenciostática mostraram a formação de um patamar difusional que obedece a equação de Levich. Os estudos de pH local revelaram a influência do equilíbrio ácido–base do íon bissulfato com formação de compostos de coordenação Cd(HSO4)+ no eletrodo de platina. Propõe-se que o íon cádmio, associado ao equilíbrio ácido–base do íon bissulfato, deposita como bissulfato de cádmio numa etapa irreversível, e seguida pela deposição de cádmio metálico reversível com a saída do íon bissulfato, sendo esta última etapa mais lenta que a primeira. Desse modo, foi calculado um modelo matemático para o mecanismo proposto, sendo realizados estudos qualitativos em relação ao comportamento da curva de polarização e do espectro de impedância eletroquímica.

O elemento químico neodímio (Nd) atualmente está em evidência pois é parte fundamental em aplicações produzidas por empresas ligadas a tecnologias limpas e de ponta. Porém, é classificado como crítico pelo departamento de energia dos EUA em função do monopólio chinês atuante em sua exploração e comercialização. Devido à crescente demanda frente à restrita disponibilidade, a recuperação deste metal está em ascensão. Uma das aplicações do neodímio é o ímã permanente de neodímio-ferro-boro, utilizado em hard disk drives (HDs) de computadores. Desta forma, este estudo visou caracterizar os ímãs provenientes de HDs de computadores e estabelecer uma rota de recuperação do neodímio por meio de processos mecânicos e hidrometalúrgicos. Por meio da pesagem dos HDs e seus ímãs obteve-se massa média de 3,04 g e 7,91 g para laptop e desktop, respectivamente, representando menos de 3% da massa total do HD. A desmagnetização foi atingida por meio de aquecimento até a temperatura de Curie, em torno de 312 °C, e a cominuição realizada em moinho de facas, onde foram obtidas três granulometrias classificadas em frações A, B e C. Qualitativamente as amostras, foram analisados por meio de difração de raios-X (DRX), onde a fase tetragonal Nd2Fe14B foi o constituinte dominante, e por meio de análise em microscópio eletrônico de varredura (MEV). Semi-quantitativamente os ímãs, seus revestimentos e o precipitado final foram avaliados por meio de espectrometria de fluorescência de raios-X (FRX). A composição média de 21,5% de neodímio e 65,1% de ferro em massa, além de outros elementos químicos, obtida por meio de espectrometria de emissão óptica com plasma (ICP-OES), mostrou teor de neodímio superior aos minérios explorados, tornando este resíduo interessante em relação à recuperação deste metal. O procedimento hidrometalúrgico adotado envolveu a lixiviação das amostras em ácido sulfúrico 2M e a variação de três parâmetros: razão sólido/líquido, temperatura e tempo, em dois níveis. Posteriormente foi realizada a precipitação seletiva por meio de NaOH, formando o duplo sal NaNd(SO4)2.nH2O. Os resultados mostraram que a lixiviação de neodímio atingiu eficiência média acima de 94%, porém todos os experimentos apresentaram material não lixiviado, majoritariamente composto por níquel e cobre. / The chemical element neodymium (Nd) currently is in evidence as it is a fundamental part in applications manufactured by clean and advanced technology companies. However, it is classified as critical by the United States Department of Energy due to Chinese monopoly in its exploration and commercialization. Due to increasing demand in contrast with scarce supply, the recovery of neodymium is growing. One of the applications of this metal is the neodymium-iron-boron permanent magnet, used in hard disk drives (HDDs) of computers. Therefore, this study aimed magnets characterizing from HDDs of computers and then establishing a recovery route for neodymium by mechanical and hydrometallurgical processes. By weighing the HDDs and their magnets it was obtained the average weight of 3.04 g and 7.91 g for laptop and desktop, respectively, representing less than 3% of the HDDs total mass. Demagnetizing was achieved by heating up to Curie temperature of around 312 °C, and the comminution in knives mill resulted in three granulometries classified into fractions A, B and C. Qualitatively, magnets were analyzed by X-ray diffraction (XRD), where the tetragonal phase Nd2Fe14B was the dominant constituent of the sample, and through analysis in a scanning electron microscope (SEM). Semi-quantitatively, the magnets, its covers, and the final precipitate were evaluated by X-ray fluorescence spectrometry (XRF). The average composition of neodymium and iron showed 21.5% and 65.1% by weight, respectively, among other chemical elements. This results were obtained by optical emission spectrometry (ICP-OES), representing a higher neodymium content compared to the ores content, which makes this waste interesting from a neodymium recovery point of view. The procedure adopted involved hydrometallurgical leaching of the samples in 2M sulfuric acid varying three parameters: liquid/solid ratio, temperature and time, each one on two levels. Subsequently, the selective precipitation by NaOH was performed to form the double salt NaNd(SO4)2.nH2O. The results showed that neodymium leaching efficiency reached above 94%, but the experiments showed as well some material left, mainly composed of nickel and copper.