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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.
1

Grain Bag Storage Systems: Monitoring, Analysis, and Effects

Ward, Jason Kellam 12 May 2012 (has links)
Grain production in the Mid-South US has exceeded traditional grain bin storage capacity in recent years. Alternative grain storage methods were adopted. One method was grain bag storage. This system has been used for silage and high moisture corn storage for decades and has been employed for dry grain in other regions of the world, but little research was available to describe the internal environment of the grain bags and its effects on grain quality. Weather conditions, agricultural methods, and cultural practices vary; therefore further research was required to assess this storage practice and describe best management practices for the local region. The objectives of this study were to develop a system and method to monitor the grain bag internal environment, to determine the internal environment and quality of dried grains stored in grain bags, and to determine the internal environment and quality of harvest moisture and condition corn stored in grain bags. An instrumentation system of thermocouples and relative humidity sensors was successfully developed. Fourier analysis was applied and sampling interval less than 10 hours was required to fully describe the grain bag environment. Commercially conditioned (dried and blended) corn (14.1 % MCwb) and soybeans (10.4 %MCwb) were stored in grain bags for 20 and 16 weeks, respectively. Corn immediately after harvest (17.1 %MCwb) was stored for 12 weeks. There were significant differences between grain in the center of the bag and peripheral temperature, with the periphery closely tracking ambient conditions. Psychrometric calculations (humidity ratio and dew-point) indicated that moisture migrated to the bag edges. Temperature within the grain mass never fell below the temperature required for condensation, condensation at the bag internal surface was likely. Grab samples did not reflect significant differences in grain moisture content across the bag profile. Geostatistical methods were used to interpolate the thermal environment of the grain bags; ordinary kriging was the best method of interpolation. Commercially conditioned corn maintained its quality while in storage, while soybeans lost one US grade. Harvest condition corn deteriorated in quality to US Sample grade while in storage. Short storage periods for early harvest corn are recommended.
2

Appropriate Accommodation for Individual Needs Allowable by State Guidelines

Jordan, Ashley Sokol 18 September 2009 (has links)
No description available.
3

Hyperbolic Coxeter groups

Moussong, Gabor January 1988 (has links)
No description available.
4

Flexão e flexo-compressão em elementos de alvenaria estrutural / Bending and bending and compression at structural masonry elements

Joaquim, Mauricio Martinelli 28 May 1999 (has links)
Este trabalho trata da verificação e dimensionamento de peças de alvenaria estrutural submetidas à flexão. Inicialmente são apresentados os conceitos básicos do método das tensões admissíveis e são desenvolvidos procedimentos para a análise do problema da flexão simples e composta reta. Em seguida discute-se o problema da flexão composta oblíqua, com ênfase à modelagem computacional necessária ao desenvolvimento de aplicativos para a análise de seções genéricas. São apresentados na seqüência dois programas computacionais, implementados a partir dos algoritmos e procedimentos desenvolvidos nos itens anteriores. Apresentam-se ainda tabelas e ábacos que permitem o cálculo das peças de alvenaria com rapidez, facilidade e segurança, algumas das quais nos moldes das já tradicionalmente utilizadas para o concreto armado. Por fim, diversos exemplos são apresentados, ilustrando a teoria exposta e a utilização de tabelas e ábacos apresentados. / This study deals with the design of structural masonry pieces subjected to bending loads. At first, basic concepts of the allowable stresses method are presented and procedures for the analysis of simple bending and composed bending are developed. Next, the oblique composed bending is discussed emphasising computational modelling for the analysis of generic cross sections. Two computational procedures based on the algorithms already developed are also shown. In addition, tables and abaci that allow analysing the design of masonry elements quickly, easily and safely are presented. Some of them are very similar to those used for reinforced concrete. Finally, several examples are presented.
5

Evaluation Of Steel Building Design Methodologies: Ts648,eurocode 3 And Lrfd

Zervent, Altan 01 May 2009 (has links) (PDF)
The aim of this study is designing steel structures with the same geometry, material and soil conditions but in the different countries, and comparing these designs in terms of material savings. According to three steel building codes, namely TS 648, LRFD, Eurocode 3, same structures with various stories (2, 4, 6, 8, and 10) are analyzed and designed. To calculate the design loads, Turkish Earthquake Code 2007 and Turkish Standard 498 (Design Load for Buildings) are utilized when TS 648 is applied. When LRFD is concerned, ASCE Standard 7-05 (Minimum Design Loads for Buildings and Other Structures) and AISC Standard 341-05 (Seismic Provisions for Structural Steel Buildings) are used for calculation of the design loads and earthquake loads. When Eurocode 3 is applied, Eurocode 8 (Earthquake Resistance Code), Eurocode 1 (Actions of Structures) and Eurocode-EN 1990 (Basis of Structural Design) are used in order to determine the design and earthquake loads. Weight of steel used on 1 m&sup2 / is almost the same for procedures of LRFD and EC3. It is important to note that those procedures consider 20 % of material saving compared to TS648.
6

Stress and Fatigue Analysis of Roller Chain under Varied Loading

Chen, Min-chiang 03 September 2008 (has links)
The stress and fatigue analysis of roller chain under varied loading is investigated in this study. With the dynamic responses of a gear-cam intermittent mechanism, boundary conditions are set up to the finite element model. The commercial MARC finite element method package is used in this work. Stress distribution is our concern. ASME elliptic equation and AGMA allowable contact stress criteria are employed in the fatigue analysis. Results indicate that the maximum of von Mises stress occurs on the contact surface between pins and plates. Besides, the initial failures on this loading are predicted to happen on the plates according to the fatigue analysis.
7

Evaluating outdoor asbestos abatement activities in an idled petroleum refinery /

Tutt, Robert Dean, January 2001 (has links) (PDF)
Thesis--University of Oklahoma. / Includes bibliographical references (leaves 49-50).
8

The Predictive Power of Commercial Fisheries Stock Assessments

Docking, Kathryn A 12 September 2018 (has links)
Organizations responsible for managing commercial fisheries conduct annual stock assessments to monitor stock and, in principle, reduce the risk of overexploitation. These are fundamental to setting the total allowable catch for the upcoming fishing year. While there have been many attempts to estimate uncertainty associated with certain components and estimates of stock assessments, to date there has been no systematic assessment of their forecasted predicted value. Using data from annual stock assessments from 65 commercial fisheries around the world, estimates were obtained of both predicted (from the previous year) and observed (in the current year) catch-at-age. When comparing observed (actual) and predicted catch-at-age for a given stock, estimates were obtained of the predictive power of next-season forecasts. Using other attributes of the fishery and the stock (biological (e.g. life history) and management (e.g. assessment model employed)), empirical models were constructed that attempt to determine variability in predictive power among stocks. It was observed that, on average, within-year predictive powers (age-series within time samples) were higher than year over year predictive powers (time-series within age samples). While focusing on time-series within age, it was observed that change over the period of record (in natural mortality rate, assessment model employed, etc.) reduced predictive power; while for age-series within time, it was shown that cumulative landings reduced predictive power. This study represents one of the first attempts to quantify systematically the predictive power of fisheries stock assessment models.
9

AvaliaÃÃo da PrevisÃo do Comportamento GeotÃcnico de FundaÃÃes Superficiais Assentes em Subsolos Arenosos de Baixa Compacidade em Fortaleza a Partir de Ensaios de Placa. / Evaluation of Forecasting Behavior Geotechnical Foundations Basements Superficial based on Sandy Low Compactness in Fortaleza From Testing Board.

Paloma Moreira de Medeiros 21 June 2013 (has links)
nÃo hà / A execuÃÃo de um projeto de fundaÃÃes superficiais requer um estudo prÃvio do subsolo de assentamento. Tal estudo inclui a estimativa da tensÃo admissÃvel e a previsÃo dos recalques aos quais a estrutura se submeterÃ. Para a previsÃo do comportamento mecÃnico, sÃo necessÃrias investigaÃÃes que tanto podem ser de campo como de laboratÃrio. Nesse contexto, o ensaio de prova de carga direta à uma alternativa interessante, pois, atravÃs dele, o comportamento da futura fundaÃÃo à reproduzido em escala praticamente real. O presente trabalho trata do estudo do comportamento de fundaÃÃes superficiais assentes em subsolos, da cidade de Fortaleza, arenosos de baixa compacidade, cuja previsÃo do comportamento à feita correntemente atravÃs de sondagens à percussÃo (SPT). A metodologia adotada no presente trabalho consiste na coleta de dados de ensaios de placa e sondagens à percussÃo em uma empresa local, coleta de amostras deformadas e caracterizaÃÃo geotÃcnica em laboratÃrio dos solos presentes nos locais de ensaio, previamente escolhidos, realizaÃÃo de provas de carga direta com placas de trÃs diÃmetros diferentes (30, 50 e 60 cm), e, por fim, realizaÃÃo de anÃlises com o objetivo de avaliar o desempenho de solos arenosos de baixa compacidade atravÃs de mÃtodos consagrados para a previsÃo da tensÃo admissÃvel, do recalque e do coeficiente de reaÃÃo vertical. A partir daÃ, foi possÃvel avaliar o desempenho de diversos mÃtodos, usualmente utilizados, em projetos de fundaÃÃes superficiais na prÃtica de Fortaleza. Foi observado que a sondagem à percussÃo (SPT) nÃo à um ensaio apropriado para a previsÃo do comportamento de solos arenosos de baixa compacidade de Fortaleza. Nesses casos, a previsÃo da tensÃo admissÃvel deve ser feita pela realizaÃÃo de ensaios mais acurados como provas de carga direta, ensaio de cone (CPT) ou, atà mesmo, com o ensaio pressiomÃtrico. AlÃm disso, quanto ao coeficiente de reaÃÃo vertical, o ensaio de prova de carga direta forneceu resultados superiores aos obtidos de correlaÃÃes com o Ãndice de resistÃncia à penetraÃÃo (NSPT) de sondagens à percussÃo. Por fim, em relaÃÃo à estimativa de recalques, o mÃtodo semi-empÃrico de DÃcourt (1992) foi o que apresentou o melhor desempenho. / The implementation of a project of shallow foundations requires a prior study of the subsoil. This study includes an allowable stress estimative and prediction of settlements to which the structure will be subjected. To predict the mechanical behavior, investigations are required which can be both field and laboratory. In this context, the plate test is an interesting alternative because, through it, the future behavior of foundation is reproduced in virtually real scale. The present work deals with the study of the behavior of shallow foundations on soils in Fortaleza city, which are sandy low compactness, whose behavior prediction is done currently through the standard penetration test (SPT). The methodology adopted in this study consists of collecting data from plate test and standard penetration test in a local company; collecting disturbed samples in test sites and doing geotechnical characterization of soils in laboratory, previously chosen; performing plate tests with three different diameters (30, 50 and 60 cm), and, finally, analyzing in order to evaluate the performance of sandy soils of low compactness through established methods for predicting the admissible stress, the settlement and coefficient vertical reaction. From there, it was possible to evaluate the performance of several methods commonly used in projects of shallow foundations in practice in Fortaleza city. It was observed that the standard penetration test (SPT) is not an appropriate test for predicting the behavior of sandy soils of low compactness of Fortaleza. In these cases, the prediction of the allowable stress should be made by using more accurate tests like plate tests, cone test (CPT) or even the pressuremeter test (PMT). Moreover, as the coefficient of vertical reaction, the plate test provided superior results to those obtained from correlations with the SPT resistance (N-value). Finally, in relation to the estimation of settlements, the semiempirical method of DÃcourt (1992) showed the best performance.
10

Flexão e flexo-compressão em elementos de alvenaria estrutural / Bending and bending and compression at structural masonry elements

Mauricio Martinelli Joaquim 28 May 1999 (has links)
Este trabalho trata da verificação e dimensionamento de peças de alvenaria estrutural submetidas à flexão. Inicialmente são apresentados os conceitos básicos do método das tensões admissíveis e são desenvolvidos procedimentos para a análise do problema da flexão simples e composta reta. Em seguida discute-se o problema da flexão composta oblíqua, com ênfase à modelagem computacional necessária ao desenvolvimento de aplicativos para a análise de seções genéricas. São apresentados na seqüência dois programas computacionais, implementados a partir dos algoritmos e procedimentos desenvolvidos nos itens anteriores. Apresentam-se ainda tabelas e ábacos que permitem o cálculo das peças de alvenaria com rapidez, facilidade e segurança, algumas das quais nos moldes das já tradicionalmente utilizadas para o concreto armado. Por fim, diversos exemplos são apresentados, ilustrando a teoria exposta e a utilização de tabelas e ábacos apresentados. / This study deals with the design of structural masonry pieces subjected to bending loads. At first, basic concepts of the allowable stresses method are presented and procedures for the analysis of simple bending and composed bending are developed. Next, the oblique composed bending is discussed emphasising computational modelling for the analysis of generic cross sections. Two computational procedures based on the algorithms already developed are also shown. In addition, tables and abaci that allow analysing the design of masonry elements quickly, easily and safely are presented. Some of them are very similar to those used for reinforced concrete. Finally, several examples are presented.

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