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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Estimativa de perda de solos por erosão laminar na bacia hidrográfica do córrego Baguaçu no Estado de São Paulo / Estimating soil loss by sheet erosion in the basin of Córrego Baguaçu in São Paulo state

Laís Coêlho do Nascimento Silva 05 October 2015 (has links)
A erosão é um fenômeno natural no modelado da superfície, no processo de remoção e de deposição de sedimentos, porém as atividades antrópicas, como o desmatamento, excedem os níveis naturais de perdas de solo. Para estimar a perda de solo anual em terrenos agricultáveis, existem modelos de predição, que relacionam elementos físicos da paisagem junto às atividades antrópicas existentes. Nessa temática, o objetivo deste trabalho é avaliar a perda de solos na Bacia Hidrográfica do Córrego Baguaçu, localizada no oeste do estado de São Paulo, considerada uma região de intensa erosão acelerada, resultado de solos provenientes de materiais arenosos e areno-argilosos de fácil erosão, isso aliado às pressões de uso agropecuário. A EUPS (Equação Universal de Perda de Solos) foi o modelo de predição utilizado para estimar a perda de solos superficiais nessa bacia. A EUPS permite avaliar o resultado dos produtos da erosividade da chuva, erodibilidade do solo, fator topográfico, cobertura do uso do solo, manejo e práticas conservacionistas. Utilizando o Sistema de Informação Geográfica (SIG), foi possível estimar espacialmente as áreas de maior vulnerabilidade a erosão, além de mapear feições lineares erosivas e apontar qual uso é mais responsável por grandes perdas de solos. Os resultados mostraram que grande parte da perda de solos na bacia concentra-se nas classes mais baixas (0 a 3 t/ha/ano), com predomínio das áreas ocupadas com pastagem e com cana-de-açúcar. / Erosion is a natural phenomenon in the modeled the surface removal process and sediment deposition, but human activities, such as deforestation, exceed natural levels of soil loss. To estimate the annual soil loss in arable land, there are models of prediction, which relate to physical elements of the landscape with anthropogenic activities. On this subject, the aim of this study is to evaluate the loss of soils in the watershed of Córrego Baguaçu, located in the west of the State of São Paulo, considered a region of intense accelerated erosion, result of soils from sandy and sandy-clay materials of easy erosion, that ally to the pressures of agricultural use. The USLE (Universal Soil loss Equation) was the prediction model used to estimate the loss of surface soils in this basin. The USLE allows you to evaluate the outcome of rainfall erosion index, soil erodibility, topographic factor, coverage of land use, management and conservation practices. Using the Geographical Information System (GIS), it was possible to estimate spatially the areas of greatest vulnerability to erosion, as well as linear features map changes and point out what is most responsible for heavy losses from soils. The results showed that much of the soil loss in the concentrates on lower classes (0 to 3 t/ha/yr), with predominance of the occupied areas with pasture and sugar cane.
92

Etude locale des mécanismes de réentrainement des microparticules en conduite ventilée / Local experimental study of microparticles resuspension mechanisms in ventilated duct under accelerated flow

Debba, Djihad 21 December 2017 (has links)
L’objectif de cette étude est de bien décrire les mécanismes impliqués dans la remise en suspension des microparticules en conduite ventilée. Une méthodologie expérimentale est utilisée, et cela en tenant compte de la période d’accélération de l’écoulement qui précède l’atteinte du régime permanent. Une méthode optique a été choisi pour étudier le mouvement initial des particules, et leur cinétique de remise en suspension. Parallèlement, nous avons recueilli des données locales de l’écoulement en période d’accélération et au régime permanent.Le démarrage de la remise en suspension a été analysé relativement à l’évolution temporelle de trois paramètres pouvant influencer le démarrage de la remise en suspension, le premier est la vitesse instantanée en proche paroi, le second est l’intensité turbulente, et enfin le troisième est l’énergie cinétique turbulente. Le paramètre prépondérant sur le démarrage de la remise en suspension semble être l’énergie cinétique turbulente. / The objective of this study is to well describe the mechanisms involved in the resuspension of particles in ventilated duct by using an experimental methodology and taking into account the acceleration of the air flow which always precedes steady state. For that purpose, we chose an optical method in order to investigate the initial movement of particles, and to quantify the resuspension kinetics. In parallel we collected local data of the flow during acceleration and steady state.We observed that the resuspension kinetics starts during the acceleration period and extends to steady state. We highlighted the relevant velocity characteristics (critical velocity at the center duct and close to the wall, critical kinetic energy range) to explain this phenomenon. The resuspension start seems to be linked with a critical kinetic energy range.
93

Ruminal characteristics and feedlot performance of steers during accelerated step-up to high-concentrate diets using Megasphaera elsdenii (Lactipro advance).

Ellerman, Tara Jo January 1900 (has links)
Master of Science / Department of Animal Sciences and Industry / James S. Drouillard / Ruminal characteristics and feedlot performance were measured for steers adapted to a high-grain diet using a traditional 22-d step-up program (Control) and for steers adapted over 10 d with the aid of M. elsdenii NCIMB 41125 fresh culture administered as an oral gavage (Fresh), an oral gavage of rehydrated lyophilized culture (Rehyd), or Rehyd combined with lyophilized culture powder administered daily as a ration top-dress (Rehyd+Daily). Yearling steers (n = 435; initial BW = 408 ± 5 kg) were blocked by weight and randomly allocated to 64 concrete surfaced pens with 7 steers/pen and 16 pens/treatment. Step-up diets contained 40, 30, and 20% corn silage, and were followed by a finishing diet containing 10% corn silage and 90% concentrate. Ruminal fluid was obtained from a subset of steers by rumenocentesis 26 h after their first feeding, and inoculated into culture tubes containing lactate medium to determine differences in capacity for lactate metabolism over 24 h. A radiofrequency pH bolus was placed in the reticulorumen of 32 steers, that measured ruminal pH every 10 min for 124 d. Steers were fed once daily ad libitum for 156 d, then weighed, and transported 450 km to a commercial abattoir for harvest. HCW and incidence of liver abscesses were determined at harvest and carcass traits were evaluated after 36 h of refrigeration. No differences were detected for feedlot performance (P > 0.20), liver abscesses (P = 0.45), or carcass traits (P > 0.20). Capacity for lactate utilization was increased with all forms of M. elsdenii, as evidenced by increases in optical density (absorbance) of M. elsdenii cultures, disappearance of lactate, and increase in butyrate production (P < 0.01). Steers on Rehyd and Rehyd+Daily treatments spent less time between pH thresholds of 5.6 > pH > 5.2 (P < 0.01); 5.2 > pH > 5.0 (P < 0.01); and pH < 5.0 (P < 0.01) than Controls throughout the finishing period. In conclusion, steers dosed with M. elsdenii can be stepped up to finishing diets in 10 d with no adverse effects on performance. Ruminal fluid containing fresh cultures or freeze-dried and rehydrated cultures of M. elsdenii NCIMB 41125 were equally effective in metabolizing lactic acid. Lyophilized M. elsdenii resulted in less time below important pH thresholds, but no further benefit of daily administration was realized in this experiment.
94

Desempenho de microbicidas para preservação de peles e couros

Fontoura, Juliana Tolfo da January 2013 (has links)
Um problema na indústria coureira é a deterioração de peles e couros devido ao desenvolvimento de microrganismos no processamento do couro. As peles e os couros contêm nutrientes adequados para o crescimento de microrganismos, como carboidratos, gorduras e proteínas, além das condições ambientais, alta umidade, temperatura de armazenagem e pH favoráveis. Alguns gêneros de bactérias e fungos sintetizam importantes substâncias deste substrato, causando modificações prejudiciais na superfície do couro e nas propriedades físico-mecânicas, deixando manchas pigmentadas de difícil remoção, afetando a qualidade do produto final e causando perda de valor comercial. Desta forma, surge a necessidade de desenvolver estratégias de controle dos microrganismos de modo a reduzir ou eliminar este problema. Para tanto, recorre-se comumente à utilização de microbicidas. No passado, a ação esperada dos agentes antimicrobianos era principalmente de fornecer uma proteção eficaz, mas em anos mais recentes, a preocupação com a sua toxicidade e com potenciais riscos ecológicos tornou-se também importante. Nos dias atuais uma grande preocupação mundial é o cuidado com a preservação do meio ambiente. Devido a isto, várias pesquisas estão voltadas para o desenvolvimento de novas tecnologias limpas e renováveis como também a otimização de processos. Tendo em vista a melhoria de processos no que diz respeito ao uso de microbicidas adicionados em peles e couros, para prevenir a contaminação dos mesmos por microrganismos, esta dissertação centrou-se na avaliação do desempenho de microbicidas comerciais convencionalmente utilizados na indústria do couro sendo eles 2-(tiocianometiltio) benzotiazole (TCMTB), isotiazolina, dispersão oleosa de 2-n-octil-4-isotiazolin-3-ona + carbendazim (OIT+BMC/óleo), dispersão aquosa de 2-n-octil-4-isotiazolin-3-ona + carbendazim (OIT+BMC/água), 2-n-octil-4-isotiazolin-3-ona (OIT) e para-cloro-meta-cresol (PCMC) contra as espécies de bactérias Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa e Streptomyces sp. e as espécies de fungos Aspergillus niger, Aspergillus flavus, Penicillium herguei e Penicillium chrysogenum. Os microbicidas foram aplicados nas etapas de remolho, píquel, curtimento de couro com cromo e curtimento/engraxe com tanino vegetal. Os efeitos antimicrobianos dos microbicidas foram avaliados através de ensaios microbiológicos acelerados de plaqueamento e de acondicionamento em câmara tropical e testes de biodeterioração no solo, seguidos de análises visual, Microscopia eletrônica de varredura e ensaio de tração. Também foi testada a sorção e wash-out dos microbicidas em couros wet-blue. Outro teste feito nos próprios microbicidas foi o de concentração inibitória mínima (MIC). Os resultados demonstraram baixa capacidade antibacteriana e antifúngica dos microbicidas selecionados quando aplicados no processo de remolho contra o ataque das bactérias Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Streptomyces sp. e no processo de engraxe para o couro curtido com tanino vegetal contra o ataque dos fungos Aspergillus niger, Aspergillus flavus. Dois dos microbicidas estudados, TCMTB e OIT+BMC/água aplicados no couro wet-blue, revelaram elevada capacidade antifúngica contra os quatro diferentes fungos testados. Dos microbicidas submetidos ao teste de absortividade e wash-out, o microbicida à base de TCMTB apresentou alta e rápida absortividade pelo couro wet-blue, além de possuir resistência à lavagem. / A problem in the leather industry is the deterioration of leather skins due to the development of microorganisms, in the processing of leather. The skin and leather containing nutrients suitable for the growth of microorganisms such as carbohydrates, fats and proteins , as well as environmental conditions, high humidity, storage temperature and pH favorable. Some genera of bacteria and fungi synthesize important ingredients of this substrate, causing harmful changes in the surface of the leather and the physical and mechanical properties, leaving pigmented spots are difficult to remove, affecting the quality of the final product and loss of commercial value. Thus, there arises the need to develop strategies for control of microorganisms in order to reduce or eliminate this problem, therefore, appeal commonly the use of microbicides. In the past, the expected action of antimicrobial agents was mainly to provide effective protection, but in more recent years, concerns about the toxicity and potential ecological risks has also become important. Nowadays a major global concern is the careful preservation of the environment, due to this many researches are focused on the development of new clean and renewable technologies as well as process optimization. In view of the improvement of processes in respect to the use of microbicides added to hides and skins to prevent contamination thereof by microorganisms , this work has focused on the evaluation of the performance of commercial microbicides conventionally used in the leather industry, 2-metiltiocianato benzothiazole (TCMTB) isothiazoline, oily dispersion of 2-n-octil-4-isotiazolin-3-ona + carbendazim (OIT+BMC/oil), water dispersion of 2-n-octil-4-isotiazolin-3-ona + carbendazim (OIT+BMC/water), 2-n-octil-4-isotiazolin-3-ona (OIT) and para-chloro-meta-cresol (PCMC), against the bacterial species Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosas and Streptomyces sp. e species of fungi Aspergillus niger, Aspergillus flavus, and Penicillium herguei Penicillium chrysogenum, compared with the control. Microbicides were applied in steps of soaking, pickling, chrome tanning and grease/tanning with vegetable tannin. The antimicrobial effects of microbicides made for these applications were evaluated by accelerated plating microbiological testing and tropical chamber rain and biodegradation tests on the ground, followed by analysis (visual , SEM and tensile test) . Also was tested the absorptivity and wash-out of microbicides in wet-blue leather. Another test done on their own microbicides was the minimal inhibitory concentration (MIC). The results showed low capacity antibacterial and antifungal activities of selected microbicides when applied in the process of soaking the attack of the bacteria Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Streptomyces. sp. e in the process of grease for leather vegetable tannin against fungal attack Aspergillus niger, Aspergillus flavus. Two of microbicides studied TCMTB and OIT + BMC/water applied in wet-blue leather, high capacity antifungal against revealed four different fungi tested. For microbicides tested for absorbency and wash-out the microbicide based TCMTB showed high and rapid absorbency by wet-blue leather also has resistance to washing.
95

Procedimento de estimação da confiabilidade dos resultados obtidos em sistemas de medição. Estudo de caso da confiabilidade do equipamento de medição do número de Swirl. / Procedure for estimating the reliability of the results obtained in measurement systems. Reliability case study of Swirl number measuring equipment.

Luis Antonio Ferraz Junior 11 May 2017 (has links)
Os sistemas de medição são projetados para obter uma capabilidade de acordo com as exigências do cliente final ou especificações de engenharia. Esta capabilidade deve ser mantida através de manutenções preventivas e calibrações. Este estudo apresenta um procedimento, onde se determina a capabilidade do sistema de medição utilizando o MSA (Measurement System Analisys). Obtendo a capabilidade, a confiabilidade das medições obtidas do sistema de medição é estimada, considerando como falha a perda da capabilidade obtida. Os tempos estimados de falha são obtidos em testes de vida acelerados utilizando como sobrecarga o aumento da temperatura e extrapolando os tempos de falha para condição de uso através dos modelos de Arrhenius-exponencial, Arrenius-Weibull e Arrhenius-lognormal. O MTTF é calculado para estimação dos tempos de manutenção e calibração do sistema de medição. Uma aplicação do procedimento proposto é realizada em um equipamento protótipo de medição do número de Swirl desenvolvido com uma nova tecnologia de medição mais rápida e precisa em relação aos existentes no mercado. O estudo avalia a capabilidade do equipamento de medição de Swril e posteriormente estima tempos de falha para obter a confiabilidade das medições obtidas e o tempo necessário para sua manutenção. / The measuring systems are designed to achieve a capability according to the requirements from the end customer or engineering specifications. This capability must be maintained through preventive maintenance and calibration. This study presents a procedure, where the measurement system capability is determined using the MSA (Measurement System Analyzes). Obtaining the capability, the reliability of the measurements obtained from the measurement system is estimated, considering as failure the loss of the capability obtained. An estimated failure times are obtained in accelerated life tests using the temperature increase as an overloading and extrapolating the failure times to condition of use through the Arrhenius-exponential, Arrenius-Weibull and Arrhenius-lognormal models. The MTTF is calculated to estimate the maintenance and calibration times for the measurement system. An application of the proposed procedure is carried out on a prototype equipment to measure the Swirl number developed with a new measurement technology faster and more accurate than others available on the market. The study evaluates the capability of equipment to measure the Swirl number and then estimates failure times to obtain the reliability of measurements obtained and the time required for their maintenance.
96

Salt Adaptation for Enhanced Growth and Sucrose Production in Cyanobacteria

Wolfe, Malory Mae 15 July 2021 (has links)
No description available.
97

Evaluation of the Potential of Residual Expansion of Concrete Affected by Alkali Aggregate Reaction

Zubaida, Nusrat 01 June 2020 (has links)
One of the biggest challenges nowadays when dealing with critical AAR-affected infrastructure is to determine the induced expansion and damage attained to date in the different locations of the structure (i.e. diagnosis), to forecast its potential for further distress over time (i.e. prognosis), as well as its potential structural implications. There are a number of prognosis techniques that have been developed in the past decades which are currently being used worldwide. Yet, most of these approaches use residual expansion procedures based on accelerated laboratory tests performed on cores extracted from damaged structures. However, the majority of the results gathered from these tests have been found to be inaccurate when compared to the swelling behavior of the respective structure in the field and several potential issues have been raised with respect to the test setup and alkali leaching. This work aims to evaluate the efficiency of the various commonly used laboratory setups to assess the residual expansion of AAR-affected concrete. Three different setups (i.e. 38°C and 100% RH; 38°C and soaked in 1M NaOH and; 38°C and wrapped in 0.7M NaOH) and two types of reactive aggregates (fine and coarse) were selected for this research. Expansion is monitored over time and four damage degrees (i.e. 0.05%. 0.12%, 0.20% and 0.30%) are selected for further chemical, microscopic (DRI) and non-destructive tests. Results demonstrated that the 1 M NaOH protocol is much more aggressive than the other two setups. Furthermore, it provides the samples with a unique damage pattern that is different from field affected concrete. Finally, the proposed setup shows to be reliable in providing tested samples with similar deterioration mechanisms than expected. Yet, more efficiency in the reaction kinetics and understanding of the alkalis exchange from the system is still required.
98

The Effect of Accelerated Instruction on Summer Regression

Voss, Pamela J 05 1900 (has links)
The purpose of this study was to evaluate the benefit accrued to fifth-grade students who participated in a summer school accelerated instruction program utilizing accelerated instructional practices in a Texas school district. The secondary intent was to determine the program's effect on student regression or retention as measured by Measures of Academic Progress (MAP) scores and State of Texas Assessment of Academic Readiness (STAAR) tests in reading and mathematics. The district provided summer accelerated instruction to fifth-grade students who did not pass reading and/or mathematics portions of STAAR for the May administration. For this study, I focused on the 2018 summer accelerated instruction offered by the district, using a mixed methods design to analyze the effectiveness of accelerated instruction for the students who participated in the summer program. A paired samples t-test was conducted to evaluate if students who failed the May STAAR in either reading or mathematics increased their scores on the June STAAR. Also, a paired samples t-test was conducted to determine if these same students increased their fall MAP test when compared to the spring MAP test. Teachers were interviewed to determine their perceptions of the most beneficial parts of summer school for students who attended. The results showed that attending the 2018 summer accelerated instruction program had a statistically significant effect on STAAR reading and mathematics scores and a statistically significant effects on the MAP reading and mathematics scores. Three themes emerged from the teacher interviews as being benefits of accelerated instruction: administrative support, a growth focus, and social and emotional health.
99

Stacked Credentials Pathways: Accelerated LPN-BSN Program

Nehring, Wendy M. 15 November 2019 (has links)
Dr. Wendy Nehring, Dean of the College of Nursing, explained that the idea to establish a LPN-BSN Program came about after a statewide tour of all the Community Colleges and Tennessee Colleges of Applied Technology (TCAT) to promote the RN-BSN Program. Students said they wanted a LPN-BSN Program that is accessible and that they get through as quickly as possible. ETSU worked with THEC to develop a hybrid program with 23 hours of articulation credits that takes four semesters to complete. ETSU is currently the only public university in Tennessee to offer a LPN-BSN Program, Dr. Nehring said. The LPN-BSN Program started at three sites in fall 2018 and has quickly expanded to seven sites, with five additional sites planned across the state. Last summer, the program received 1,000 inquiries per week. In fall 2019, 94 students enrolled, which is close to the enrollment in the BSN Program on ETSU’s main campus. Spring 2020 enrollment is estimated to be just over 100 students. At this time, Dr. Nehring said the highest interest is coming from Crossville and Nashville, and students at the Memphis TCAT petitioned their President to offer the LPN-BSN Program. The state is experiencing a nursing shortage, especially in rural areas, so this program is one way TSU is working to meet workforce needs.
100

Accelerated Life Testing Of Subsea Equipment Under Hydrostatic Pressure

Thiraviam, Amar Raja 01 January 2010 (has links)
Accelerated Life Testing (ALT) is an effective method of demonstrating and improving product reliability in applications where the products are expected to perform for a long period of time. ALT accelerates a given failure mode by testing at amplified stress level(s) in excess of operational limits. Statistical analysis (parameter estimation) is then performed on the data, based on an acceleration model to make life predictions at use level. The acceleration model thus forms the basis of accelerated life testing methodology. Well established accelerated models such as the Arrhenius model and the Inverse Power Law (IPL) model exist for key stresses such as temperature and voltage. But there are other stresses like subsea pressure, where there is no clear model of choice. This research proposes a pressure-life (acceleration) model for the first time for life prediction under subsea pressure for key mechanical/physical failure mechanisms. Three independent accelerated tests were conducted and their results analyzed to identify the best model for the pressure-life relationship. The testing included material tests in standard coupons to investigate the effect of subsea pressure on key physical, mechanical, and electrical properties. Tests were also conducted at the component level on critical components that function as a pressure barrier. By comparing the likelihood values of multiple reasonable candidate models for the individual tests, the exponential model was identified as a good model for the pressure-life relationship. In addition to consistently providing good fit among the three tests, the exponential model was also consistent with field data (validation with over 10 years of field data) and demonstrated several characteristics that enable robust life predictions in a variety iv of scenarios. In addition the research also used the process of Bayesian analysis to incorporate prior information from field and test data to bolster the results and increase the confidence in the predictions from the proposed model.

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