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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.
331

Vibrational and mechanical properties of disordered solids

Milkus, Rico January 2018 (has links)
The recent development of a framework called non-affine lattice dynamics made it possible to calculate the elastic moduli of disordered systems directly from their microscopic structure and potential energy landscape at zero temperature. In this thesis different types of disordered systems were studied using this framework. By comparing the shear modulus and vibrational properties of nearest neighbour spring networks based on depleted lattices we were able to show that the dominating quantity of the system’s non-affine reorganisation during shear deformation is the affine force field. Furthermore we found that different implementation of disorder lead to the same behaviour at the isostatic point. Later we studied the effect of long range interaction in such depleted lattices with regard to spatial correlation local elasticity. We found that the implementation of long springs with decaying spring constant reproduced the spatial correlation observed in simulations of Lennard-Jones glasses. Finally we looked at simple freely rotating polymer model chains by extending the framework to angular forces and studied the dependence of the shear modulus and the vibrational density of states (VDOS) and length and bending stiffness of the chains. We found that the effect of chain length on the shear modulus and the vibrational density of states diminishes as it depends on the number of backbone bonds in the system. This number increases fast for short chains as many new backbone bonds are introduced but slows down significantly when the chain length reaches 50 monomers per chain. For the dependence on the bending stiffness we found a rich phenomenology that can be understood by looking at specific motions of the monomers relative the the chain geometry. We were able to trace back the different regimes of the VDOS to the simple model of the triatomic molecule. We also explored the limits of non-affine lattice dynamics when describing systems at temperatures T > 0 and gave an approximate solution for the shear modulus in this case.
332

Short-Term Reduction of Peak Loads in Commercial Buildings in a Hot and Dry Climate

January 2012 (has links)
abstract: A major problem faced by electric utilities is the need to meet electric loads during certain times of peak demand. One of the widely adopted and promising programs is demand response (DR) where building owners are encouraged, by way of financial incentives, to reduce their electric loads during a few hours of the day when the electric utility is likely to encounter peak loads. In this thesis, we investigate the effect of various DR measures and their resulting indoor occupant comfort implications, on two prototype commercial buildings in the hot and dry climate of Phoenix, AZ. The focus of this study is commercial buildings during peak hours and peak days. Two types of office buildings are modeled using a detailed building energy simulation program (EnergyPlus V6.0.0): medium size office building (53,600 sq. ft.) and large size office building (498,600 sq. ft.). The two prototype buildings selected are those advocated by the Department of Energy and adopted by ASHRAE in the framework of ongoing work on ASHRAE standard 90.1 which reflect 80% of the commercial buildings in the US. After due diligence, the peak time window is selected to be 12:00-18:00 PM (6 hour window). The days when utility companies require demand reduction mostly fall during hot summer days. Therefore, two days, the summer high-peak (15th July) and the mid-peak (29th June) days are selected to perform our investigations. The impact of building thermal mass as well as several other measures such as reducing lighting levels, increasing thermostat set points, adjusting supply air temperature, resetting chilled water temperature are studied using the EnergyPlus building energy simulation program. Subsequently the simulation results are summarized in tabular form so as to provide practical guidance and recommendations of which DR measures are appropriate for different levels of DR reductions and the associated percentage values of people dissatisfied (PPD). This type of tabular recommendations is of direct usefulness to the building owners and operators contemplating DR response. The methodology can be extended to other building types and climates as needed. / Dissertation/Thesis / M.S. Architecture 2012
333

The effect of flywheel training on functional neuromuscular performance in physically active youth

Westblad, Niklas January 2018 (has links)
Aim The aim of this study was to investigate the effect of flywheel resistance training on functional neuromuscular performance in physically active youth.   Method Forty-four healthy and physically active youth between 12-14 years of age (n=19 boys & n=25 girls) volunteered to participate and were randomized into three different groups of flywheel resistance training (FRT) (n=15, body mass = 42,9 ± 8,6 kg, time to Peak Height Velocity (PHV) = - 0,8 ± 1,6), traditional strength training (TST) (n=15, body mass = 44,7 ± 10,3 kg, time to PHV = - 0,8 ± 1,5) and a control group (CON) (n=14, body mass = 43,8 ± 9,0 kg, time to PHV- 0,8 ± 1,5. Squat jump (SQ), Countermovement jump (CMJ), 10-m acceleration, 20-m speed and 30-sprint was assessed pre- and post-intervention. All training groups performed 12 resistance training sessions over a 6-week intervention. The FRT-group performed bilateral flywheel resistance squats with 4 sets of 6 repetitions with 0,025 to 0,05 kgm2 and the TST-group performed bilateral barbell squats with 4 sets of 6 repetitions at a predicted 80 %1RM, while the control group only performed their regular sports training.   Results Repeated measures two way-ANOVA, 3 x 2 (training group x time), showed no significant mean effects between groups after the intervention. A significant increase occurred in the control group for SQ; 2,4 ± 2,5 (cm) p ≤ 0,008 and CMJ; 2,2 ± 3,1 (cm) p ≤ 0,037. Both training groups increased significantly in body mass from pre- to post-tests by 2,0 ± 2,7 kg for the flywheel training group and 1,3 ± 0,9 kg in the traditional strength training group (p ≤ 0,05).   Conclusions This study indicates that flywheel training can be used as a resistance training method for youth athletes without inducing training related injuries. Flywheel resistance training resulted in a small but non-significant increase from pre to post test in squat jump and 10-m sprint. Future studies on flywheel resistance training for youth needs to investigate the implementation of longer training periods, additional training sessions, more experienced youth in resistance training and faster movement speed.
334

Efeitos do treinamento proporcionado pelo método pilates clássico nas aptidões físicas em mulheres saudáveis : um ensaio clínico controlado / The effects of classical pilates training on physical activites on health women : a controlled trial

Picolli, Francine January 2010 (has links)
Introdução: O Método Pilates apesar de prática difundida, apresenta escassez de evidências que demosntrem sua eficácia. Objetivos: Verificar a adaptação cardiorrespiratória, antropométrica e parâmetros da aptidão física ao treinamento proporcionado pela prática do Método Pilates Clássico. Métodos: Participaram deste estudo quinze mulheres saudáveis (GP) as quais realizaram o treinamento no Método Pilates Clássico, durante 12 semanas, 3 vezes por semana e 13 controles saudáveis (GC) que mantiveram sua rotina de atividades. Foi avaliado consumo máximo de oxigênio, pressão arterial, peso, percentual de gordura, massa gorda, massa corporal magra, amplitude de movimento articular, flexibilidade, resistência muscular localizada (abdominais, membros superiores e membros inferiores) e equilíbrio dinâmico antes e após o treinamento para o GP e antes e após 12 semanas para GC. Ocorreu monitoramento da frequência cardíaca em cada sessão do treinamento para o GP. Resultados: O presente estudo demonstrou que houve redução no percentual de gordura (p < 0,001) e aumento da massa corporal magra (p < 0,001). A amplitude de movimento articular e a flexibilidade, avaliadas em todas as articulações, tiveram melhora (p < 0,001), assim como a ressitência msucular localizada (p < 0,001) e o equilíbrio dinâmico ( p = 0,001). Além disso, este é o primeiro ensaio clínico que demonstra melhora da capacidade funcional, avaliada pela medida do VO2 pico (p < 0,001). Conclusão: Os resultados apresentados sugerem que mulheres, previamente sedentárias, se beneficiaram com a melhora significativa da aptidão física, tanto parâmetros motores, quanto físicos, apresentando alterações significativas na composição corporal, na amplitude de movimento articular, na flexibilidade, na resistência muscular localizada e no equilíbrio dinâmico. Além disso, o incremento da capacidade funcional atavés do VO2 pico. / Introduction: Despite it widespread practice, the Pilates Method presents scarcity of relevant scientific evidence of justify its efficacy. Objectives: To present a comprehensive evaluation of the adaptations to cardiorespiratory parameters, anthropometric and physical fitness provided by the practice of the Pilates Method. Methods: Fifteen healthy participants (PG) who underwent training in the Classical Pilates Method for 12 weeks, 3 times a week were evaluated against 13 healthy controls (CG) who maintained their routine activities. Measurements of VO2 peak, blood pressure, weight, fat percentage, fat mass, lean body mass, range of movement, flexibility, muscular endurance (abdominal, upper and lower limbs) and dynamic balance before and after training for the PG, and before and after 12 weeks for CG were taken. Heart rate was monitoring at each training session for the PG. Results: The study showed that the exercises practiced resulted in a reduction in body fat percentage (p <0.001) and increased lean body mass (p <0.001). The range of motion and flexibility in all joints evaluated, reported improvement (p <0.001), as well muscle endurance (p <0.001) and dynamic balance (p = 0.001). Moreover, this is the first clinical trial that demonstrates improved functional capacity, assessed by measurement of VO2 peak (p <0.001). Conclusion: The results suggest that sedentary women obtain significant changes in body composition, joint range of movement, flexibility, muscular endurance and dynamic balance from practicing Classical Pilates Method 3 times a week. Furthermore, they increased the functional capacity through the VO2 peak.
335

Classificação dos exercícios do Jump Fit a partir de parâmetros relativos ao impacto

Schiehll, Paulo Eduardo January 2007 (has links)
As lesões decorrentes da prática da ginástica desde o início dos anos 70 tem aumentado a atenção dos pesquisadores. Tem sido documentado por diversos autores que 43 % dos praticantes e 76 % dos instrutores de aeróbica de alto impacto sofrem lesão, sendo que o impacto da aterrissagem é um dos momentos de maior risco nos membros inferiores em muitas destas modalidades terrestres. Diante disso, percebe-se a necessidade de estudos específicos que analisem adequadamente o comportamento do impacto durante aulas de ginástica inclusive na modalidade de ginástica JUMP FIT®. Objetivo deste estudo foi classificar os exercícios do JUMP FIT® a partir de parâmetros relativos ao impacto. Participaram sessenta professores de ambos os sexos, com mínimo de 6 meses de experiência na modalidade JUMP FIT®. Para a aquisição dos dados da força de reação do solo o minitrampolim foi instrumentado com 6 células de carga marca HBM, modelo PW 10 D1. O presente estudo mostrou que existe simetria na FRS entre os lados direito e esquerdo, com maiores valores para o lado esquerdo, apenas nos exercícios femoral simples e elevação de joelhos. Os mecanismos que levam a estas assimetrias ou mesmo suas conseqüências sobre o sistema músculoesquelético permanecem desconhecidas. Apartir dos resultados obtidos, sugere-se uma classificação associada ao pico de força e outra associada à taxa de aplicação de força. / The injuries due to the practice of the gymnastics since the beginning of 70´s have increased the attention of researchers. It has been documented for diverse authors that 43% of who practices and 76% of the aerobics’ instructors of high impact suffer injury, and the impact of the landing is one of the moments of major risk in the lower limbs in many of these terrestrial modalities. Because of this, it is perceived the necessity of specific studies that adequately analyze the behavior of the impact during lessons of gymnastics also in the modality of gymnastics JUMP FIT®. The aim of this study was to classify the exercises of JUMP FIT® from parameters related to the impact. Participated of this study sixty professors of both sex, with minimum of 6 months of experience in modality JUMP FIT®. For the acquisition of the data of the reaction force of the ground the mini springboard was instrumented with 6 mark’s cells HBM, model PW10 D1. The present study showed that exist symmetry in the FRS between the left and the right sides, with bigger values for the left side, only in the exercises simple femoral and elevation of knees. The mechanisms that take to these asymmetrical or even the consequences on the system skeletal-muscle remain unknown. From the obtained results we suggest a classification related to force peak and another to force load rate.
336

Emprego de ferramentas quimiométricas na cromatografia a gás para determinar a origem do biodiesel

Lopes Neto, Vanjoaldo dos Reis January 2012 (has links)
134 f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-09-19T14:49:05Z No. of bitstreams: 1 Tese_Vanjoaldo Lopes.pdf: 3691974 bytes, checksum: 4acbb7d5e3b7ac76fe0b2ff6e4a01cc2 (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-09-19T15:13:57Z (GMT) No. of bitstreams: 1 Tese_Vanjoaldo Lopes.pdf: 3691974 bytes, checksum: 4acbb7d5e3b7ac76fe0b2ff6e4a01cc2 (MD5) / Made available in DSpace on 2013-09-19T15:13:57Z (GMT). No. of bitstreams: 1 Tese_Vanjoaldo Lopes.pdf: 3691974 bytes, checksum: 4acbb7d5e3b7ac76fe0b2ff6e4a01cc2 (MD5) Previous issue date: 2012 / CAPES, FAPESB, CNPQ / Buscando minimizar a dependência dos combustíveis fosseis, fontes energéticas alternativas e renováveis estão em franco desenvolvimento, ganhando cada vez mais espaço na matriz energética mundial e levando à diminuição dos impactos ambientais. Neste contexto, muitas pesquisas são realizadas, buscando o aumento da produção de biodiesel e a garantia da sua qualidade. Em um país como Brasil, que possui vasto território, onde muitas oleaginosas e gorduras animais podem ser usadas para produzir biodiesel, investigar a origem do biodiesel é uma necessidade, uma vez que a qualidade do biodiesel está relacionada às matérias-primas que o produziu. Neste trabalho, determinou-se a composição de amostras de biodiesel em relação aos tipos de matéria-prima através da cromatografia a gás associada à calibração multivariada. Para tal, foram desenvolvidas três modelagens por PLS, a partir de cromatogramas de amostras de biodiesel obtidos empregando a norma EN 14103, onde foi possível identificar, com segurança estatística, a composição das matérias-primas de amostras de B100. As duas primeiras modelagens foram realizadas com as áreas dos picos cromatográficos e com as áreas normalizadas, respectivamente; nestas duas modelagens, os picos foram integrados manualmente. Na terceira modelagem, os cromatogramas foram previamente alinhados usando o algoritmo COW, e todo o cromatograma foi explorado pelo PLS. Os procedimentos foram aplicados a misturas de biodiesel quaternárias (soja, sebo bovino, girassol e dendê), sendo alcançados parâmetros similares para as duas primeiras modelagens na determinação da composição do biodiesel quanto as suas matérias-primas. Na modelagem das áreas não normalizadas, nos conjuntos de calibração encontraram-se valores de RMSEC < 4,40%; RMSECV < 5,36%; R2 (calibração) > 0,973 e R2 (Validação Cruzada) > 0,962; o conjunto de previsão apresentou correlação > 0,992 e RMSEP < 3,57%. Para a modelagem das áreas normalizadas, encontraram-se valores: RMSEC < 4,70%; RMSECV < 5,34%; R2 (calibração) > 0,985; R2 (Validação Cruzada) > 0,963; correlação > 0,989 e RMSEP < 3,43%. A terceira modelagem, com os cromatogramas totais alinhados, encontraram-se valores: RMSEC < 5,35%; RMSECV < 9,14%; R2 (calibração) > 0,955 e R2 (Validação Cruzada) > 0,875; Correlação > 0,966 e RMSEP < 7,19%. As duas primeiras modelagens estabeleceram parâmetros análogos, exatos e seguros para avaliar o teor de cada tipo de biodiesel na composição da mistura B100. A terceira modelagem apresentou parâmetros inferiores aos das duas primeiras modelagens; este fato pode ser explicado porque, nesta modelagem, a altura (sinal) foi a variável avaliada, e por sua vez a altura é um dado cromatográfico de menor confiabilidade que a área dos picos. / Salvador
337

Caracterização hidrogeológica de bacias hidrográficas do semiárido baiano através de técnicas de geoprocessamento / Hydrogeological characterization of watersheds in the semi arid baiano using GIS techniques.

Silva, Edivam José da January 2009 (has links)
SILVA, Edivam José da. Caracterização hidrogeológica de bacias hidrográficas do semiárido baiano através de técnicas de geoprocessamento. 2009. 154 f. : Dissertação (mestrado) - Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2009. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-20T16:57:00Z No. of bitstreams: 1 2009_dis_ejsilva.pdf: 5950080 bytes, checksum: e144fd081701380936a030afd298b361 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-20T16:57:46Z (GMT) No. of bitstreams: 1 2009_dis_ejsilva.pdf: 5950080 bytes, checksum: e144fd081701380936a030afd298b361 (MD5) / Made available in DSpace on 2016-06-20T16:57:46Z (GMT). No. of bitstreams: 1 2009_dis_ejsilva.pdf: 5950080 bytes, checksum: e144fd081701380936a030afd298b361 (MD5) Previous issue date: 2009 / For the adoption of water resources management in dry regions where water availability is limited, knowledge of the different processes of the hydrological cycle is needed, especially the precipitation and flow. Therefore, techniques of GIS are essential in studies of hydrological modeling. The study on maximum flow in a watershed is important because the same act on soil erosion, flooding in urban and rural areas, hydraulic works, among others. The Salitre basin is located in the State of Bahia, Brazil, and its Pacui sub-basin is fully inserted in the Campo Formoso municipio. With a drainage area of 987.74 km2, it is one of the main drainage sub-basin of Salitre river. Hence, the objective of this work was to characterize physiographically the Pacui sub-basin, estimate peak flow by USDA-SCS and Dooge methods, and estimate the hourly evapotranspiration in the sub-basin using the algorithm SEBAL (Surface Energy Balance Algorithms for Land) and images from Landsat 7 - ETM. The Global Mapper software was used for the analysis of land numerical model (SRTM). The ENVI 4.3 software was used for georeferencing of data from topographic maps of SUDENE, and the Arcmap 9.2 software was used for watershed delineation. The time of concentration was determined by USDA and Dooge methods. To determine the radiation balance images from the INPE (National Institute for Space Research) were used and processed by Arcmap ® software, within algorithm SEBAL was developed. The basin presented low slope and then tends to reduce the flood peak because of the low speed runoff. ArcHidro proved to be an effective tool in the delineation of river basins and the generation of drainage network and compared with those obtained by maps from SUDENE. The algorithm SEBAL proved to be an agile and efficient tool in evapotranspiration estimation. The use of SRTM provided information of parameters as surface albedo, incident long-wave and shortwave radiations, pixel to pixel. Lower rates of hourly evapotranspiration (<0.15 mm.h-1) were recorded in areas of exposed soils, and higher rates were found in irrigated areas and vegetation, expressing the sensitivity of algorithm SEBAL on evapotranspiration estimation in watershed scale / Para a adoção de uma gestão adequada dos recursos hídricos tendo como unidade de planejamento a bacia hidrográfica, o conhecimento dos diferentes processos do ciclo hidrológico se faz necessário, notadamente da precipitação, do escoamento e da evapotranspiração. Portanto, técnicas de geoprocessamento são imprescindíveis nos estudos de modelagem hidrológica a nível de bacias hidrográficas. O estudo sobre o escoamento superficial, em uma bacia hidrográfica é importante pelo fato do mesmo atuar sobre a erosão do solo, inundações em áreas rurais e urbanas, obras hidráulicas, entre outros. A bacia do rio Salitre esta localizada no Estado da Bahia, e a sub-bacia do rio Pacui esta inserida totalmente no município de Campo Formoso, com área de drenagem de 987,74 km2, constituindo umas das principais subbacias de drenagem para o rio Salitre. Nesse contexto, objetivou-se caracterizar fisiograficamente a sub-bacia rio Pacui e bacia do rio Salitre, analisar a estimativa de vazão de pico pelos métodos de SCS-USDA e de Dooge, e estimar a evapotranspiração horária na bacia do rio Pacui utilizando-se o algoritmo SEBAL (Surface Energy Balance Algorithms for Land) e imagens do Landsat 7 – ETM. Utilizou-se os softwares Global Mapper, para análises do modelo numérico do terreno (SRTM), ENVI 4.3, para georeferenciamento dos dados tendo como base as cartas topográficas da SUDENE e do software ArcMap 9.2 para delimitação automática de bacias. O tempo de concentração foi determinado pelos métodos USDA e de Dooge. Para determinar o balanço de radiação utilizou-se de imagem da região obtida junto ao INPE (Instituto Nacional de Pesquisas Espaciais) e processadas na ferramenta álgebra de mapa no software ArcMap® onde foi desenvolvido o algoritmo SEBAL. A bacia apresenta baixa declividade, portanto tende a uma redução dos picos de descargas devido à baixa velocidade de escoamento superficial. A extensão ArcHidro mostrou-se uma ferramenta eficaz na delimitação de bacias e na geração de rede drenagem, comparando com as obtidas pelas cartas da DSG/SUDENE. O algoritmo SEBAL mostrou-se uma ferramenta ágil e eficiente na estimativa da evapotranspiração. A utilização do SRTM proporcionou ganhos de informações nos parâmetros albedo da superfície, radiação de ondas longas incidente, radiação de onda curtas incidente, pixel a pixel. Menores taxas de evapotranspiração horária (< 0,15 mm.h-1) foram registradas em áreas de solos expostos e as maiores nas áreas irrigadas e vegetação no geral, expressando a sensibilidade do algoritmo SEBAL na estimativa da evapotranspiração em escala de bacias hidrográficas.
338

An Investigation of the Reliability and Validity of PEAK Relational Training System: An Effective Behavioral Intervention for Children with Autism and Developmental Disabilities

McKeel, Autumn Nicole 01 August 2013 (has links)
The current set of experiments sought to evaluate and address current, empirically based assessments and treatment protocols for children who have autism and/or other developmental disabilities. The past few decades of research have been successful in developing effective behavioral treatments, however, the dissemination of these strategies has not been maximized in applied settings. Furthermore, many existing treatments are outdated or not widely used in school or social settings. The current experiments evaluate existing effective assessments and treatments and extend them with the implementation of a novel package based off of commonly utilized discrete trial training behavioral techniques in behavior analysis. This treatment protocol was shown to have high inter observer reliability scores throughout the use of this assessment, as well as a high correlation with a commonly used language assessment in Experiment 1. Experiment 2 examined the positive effects of this treatment curriculum guide following skills training. Experiment 3 evaluated the validity of the programs that examined higher order learning from Skinner's (1957) analysis of verbal behavior. The results suggest that this assessment and training protocol has significant potential in efficiently training students with and without disabilities. Implications of these finding are discussed in terms of future progress of translational research in applied settings. Furthermore, the present set of experiments contributes largely to the dissemination of emerging research and practice in behavior analysis.
339

Teaching Money Skills Using the PEAK Equivalence Module

Zosel, Jennifer 01 May 2015 (has links)
The present study evaluated the use of stimulus equivalence to train novel money relations with adults with developmental disabilities. Three programs from the PEAK Relational Training System: Equivalence Module (PEAK-E) were used: Reflexivity: Money, Symmetry: Money to Monetary Value and Equivalence: Monetary Exchange. The overall goal of the study was to evaluate how stimulus equivalence could help the subjects improve money skills, a socially significant behavior for all adults. The study used a multiple probe design across programs to evaluate skill acquisition following the train/test procedure for each program. Results demonstrated a significant increase in PEAK scores from baseline probes for two of the three programs for all subjects. Additionally, results showed that all subjects learned untrained skills. The results of this study demonstrated the value of stimulus equivalence for teaching money skills as well the efficacy of the PEAK-E training system to teach adults with developmental disabilities.
340

AN IMPROVED ROCK MASS BEHAVIOR NUMERICAL MODEL AND ITS APPLICATIONS TO LONGWALL COAL MINING

Abbasi, Behrooz 01 May 2016 (has links)
TITLE: AN IMPROVED ROCK MASS BEHAVIOR NUMERICAL MODEL AND ITS APPLICATIONS TO LONGWALL COAL MINING The rock mass constitutive models should include elastic moduli, strength and stiffness of intact rock as well as those of joints and geometric properties of joints. The post-failure behavior of intact rock and joints must also be specified. A direct application of the above comments is in longwall coal mining where the coal as well as the immediate roof and floor strata may undergo controlled brittle failure and associated weakening in tension and shear based on post- failure characteristics of the rock mass. In addition to controlled failure and weakening of the rock mass ahead and over the longwall face, large scale caving and compaction of caved materials occur behind the longwall face. Itasca’s Cave-Hoek three dimensional constitutive model has the ability to model longwall mining process that involve the above mentioned mechanism of rock mass failure and compaction. However, its testing to date is limited. The overall goals of research are two-fold: 1) Develop numerical modeling approaches that consider the caving behavior of jointed rock masses in design and analysis, and 2) Apply these techniques in designing stable chain-pillars and set-up rooms for longwall coal mining. Specific objectives are to: 1) Develop an improved constitutive model for prediction of post-peak behavior of rock masses typical of longwall mining in Illinois, 2) Implement the improved model for predicting gob material behavior using FLAC3D numerical code (most commercial codes do not have a built in model for gob material) and its effects on load transfer into gate entries, 3) Identify mechanisms of instability in setup rooms, 4) Develop alternate 3- and 4-entry set-up room geometries using 3-D numerical analyses, 5) Implement and field demonstrate developed geometries, and 6) Monitor performance of implemented geometries through field monitoring. An alternative method to estimate the residual strength of a rock mass is developed. A yielded rock mass and a rock fill have several common characteristics including dilation behavior under low confinement and extensive crushing of contact points under high stress, which decrease dilation. The residual strength takes on an initial value in the immediate post-peak (corresponding to near-zero porosity) condition, then degrades to an ultimate residual strength that is lower as a result of bulking, a corresponding increase in porosity, and a drop in interlock under continued shear. The following comments summarize the key findings of this research: • The model for predicting rock fill material shear strength was used as a residual strength criterion. A relationship for estimating Hoek-Brown residual parameters as a function of equivalent roughness of rock fill particles and basic friction angle was used. • Macro-level measurements around setup rooms and gate entry development areas indicated that most of the observed ground control problems may be related to subsidence movements over the setup rooms area. • Mechanisms that may be responsible for poor ground conditions in setup rooms and adjoining gate entries were identified. Collected field data and numerical analyses results tend to support the identified mechanisms. • The integrated field monitoring and numerical modeling study here assisted the cooperating coal company to plan for additional supports in development entries impacted by the fault zone and in taking appropriate safety measures while the longwall face advanced toward the fault and crossed it.

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