Made available in DSpace on 2014-08-20T14:38:43Z (GMT). No. of bitstreams: 1 Dissertacao_Luciane_Silva_Martins.pdf: 555347 bytes, checksum: 0b7fbb035e111d7955facc7abe839ff2 (MD5) Previous issue date: 2011-02-21 / Thirty eight (38) castrated male goats were used to evaluate carcass tissue and regional composition. Animals were raised under extensive range conditions, in two family units, in the 2nd sub-district of Palmas, Bagé, State of RS, Brazil, localized within the area known as Alto Camaquã Territory. Twenty (23) animals born during June/July 2008, and were slaughtered in June 2009, with approximately 11-12 months of age. Fifteen (15) animals born in March/April 2009 were slaughtered in December 2009, with approximately 8-9 months of age. Carcasses were separated longitudinally in two halves. Afterwards six cuts were obtained: foreleg, hind-leg fluctuating ribs, fixed ribs, neck and breast, each one being weighed, to calculate the proportion in relation to the corrected cold carcass weight. Different cuts obtained were frozen for later tissue evaluation. Foreleg and hind-leg were defrosted and dissect to determine muscle tissue composition, bone, subcutaneous fat, inter-muscular fat and other tissues. Each resulting tissue was weighed and its proportion calculated in relation to the corrected weight. Data were submitted to variance analysis (proc. GLM). Results demonstrated significant differences (P<0.05) between the age of slaughter in carcass regional components, whereas foreleg and hind-leg tissue composition did not differ significantly for the majority of the variables analyzed. However, 8-9 months goats showed greater relation for muscle:fat in foreleg compared to 11-12 months animals. Thus, naturalized goats of the Alto Camaquã Territory, grown extensively and slaughtered in December, or slaughtered in June with 11-12 months age, presented different tissue and regional composition in carcasses. Therefore, it is not recommended to include these two group types in a same meat brand (indication of quality) classification. / Para avaliar a composição regional e tecidual da carcaça foram utilizados 38 cabritos machos castrados, criados de forma extensiva em duas unidades de pecuária familiar no 2º subdistrito das Palmas/Bagé-RS, localizado dentro do Território do Alto Camaquã. Parte destes animais (23) nasceu entre os meses de junho e julho de 2008 e foi abatido em junho de 2009, com aproximadamente 11-12 meses de idade. O restante dos animais (15) nasceu entre os meses de março e abril de 2009 e foi abatido em dezembro do mesmo ano com, aproximadamente, 8-9 meses de idade. Após o abate as carcaças foram divididas longitudinalmente em duas metades. Posteriormente, foram obtidos seis cortes: paleta, perna, costelas flutuantes, costelas fixas, pescoço e peito, sendo cada um deles pesado e calculada sua proporção em relação ao peso da meia carcaça fria corrigido. Os diferentes cortes obtidos foram congelados para posterior avaliação tecidual. Os cortes de paleta e perna foram submetidos a descongelamento e dissecados, para determinação da composição tecidual em músculo, osso, gordura subcutânea, gordura intermuscular e outros tecidos. Cada tecido que compunha os cortes foi pesado e sua proporção calculada em relação ao peso do corte corrigido. Os dados foram submetidos à análise de variância (procedimento GLM). Os resultados demonstraram que foram encontradas diferenças significativas (P<0,05) entre idade de abate nos componentes regionais da carcaça, enquanto que, no que se refere à composição tecidual da paleta e da perna não foram encontradas diferenças significativas na maior parte das variáveis analisadas. Porém, cabritos aos 8-9 meses tiveram maior relação músculo:gordura na paleta que os cabritos aos 11-12 meses. Deste modo, cabritos naturalizados do Território Alto Camaquã , criados em sistema extensivo, abatidos em dezembro com 8-9 meses e abatidos em junho com 11-12 meses de idade apresentam carcaças com composição regional e tecidual distintas, não sendo recomendado estarem em uma mesma marca de carne.

Made available in DSpace on 2014-08-20T13:44:49Z (GMT). No. of bitstreams: 1 dissertacao_carlos_gustavo_karam_de_oliveira.pdf: 610763 bytes, checksum: 9340a1e45ba1104633287693f7fb392a (MD5) Previous issue date: 2010-12-23 / The objective this research is to determine the relation between the levels of genetic contamination (Female), density of sowing and hybrid types of irrigated rice to productivity. The experiment was carried out at an experiment camp of the Rice Tec Company, in the city of Glorinha (RS/BRAZIL), in the agricultural year of 2009/2010. The variables were four genetic contaminations (0%, 10%, 20% and 30%) three seed rate (35, 45 and 55 kilograms/hectare) and two hybrids (Avaxi CL and Inov), while the variable of result was yield. For the Avaxi CL there was no difference concerning productivity when the genetic contamination was increased. On the Other hand, the Inov hybrid showed the important yield difference in when the genetic contamination was increased and with different sowing densities. / O presente trabalho teve como objetivo determinar a influência de níveis de contaminação genética (Fêmea), densidade de semeadura e tipos de híbridos de arroz irrigado com a produtividade. O experimento foi conduzido no campo experimental da empresa RiceTec no município de Glorinha, RS no ano agrícola de 2009/2010. As variáveis foram quatro contaminações genéticas (0%; 10%; 20% e 30%), três densidades de semeadura (35; 45 e 55 kg/ha) e dois híbridos (Avaxi CL e Inov), enquanto a variável resposta foi rendimento por hectare. No híbrido Avaxi CL não houve diferença em relação à produtividade quando se aumentou a contaminação genética. Por outro lado, o híbrido Inov apresentou diferença significativa na produtividade quando do aumento da contaminação genética e nas diferentes densidades de semeadura

Underground excavations break the balance of the initial stress field and cause stress redistributions in the surrounding rock masses. Problems normally arise as the stress exceeds the rock mass strength. In addition, the rock mass contains preexisting defects, such as the fissures, fractures, joints, faults, shear zones, dikes, etc., which could significantly weaken the rock mass strength and make the rock mass behavior complicated. The stability of underground excavations is of great importance to an operating mine project since it ensures the safety of the working environment and the successful ore exploration. Due to the complex geological conditions and engineering disturbances, the assessment of rock mass stability for a practical engineering problem is extremely challenging and difficult, which needs to be solved by the modern numerical methods. In this dissertation, the rock mass stability around tunnels in an underground mine in the USA was investigated by performing three-dimensional modeling using the 3DEC 3-Dimensional Distinct Element Code. Comprehensive stress analyses were respectively carried out on a preliminary model and a more advanced model. In the preliminary study, the built model contains the inclined lithologies, a non-persistent fault, and a convoluted tunnel system. The geomechanical property values used for the rock masses and discontinuities in the numerical model were estimated using the available geotechnical information and the experience of the research group. The Mohr-Coulomb and strain softening constitutive relations were prescribed for the rock masses; the coulomb slip joint model was assigned for the discontinuities. The influence of the boundary conditions, block constitutive models, horizontal in situ stress and rock support system on the tunnel stability was investigated. The rock mass behavior was quantified using the results of stress, displacement, and yielded zones around the tunnels. It showed that the roller boundary conditions resulted in slightly different but comparable results with the combined boundary conditions (roller and stress combined) where K0 equals to 0.4 or 0.5. Whereas the in-situ stress field for a complex geological system can only be obtained by applying proper boundary stresses and then by performing stress analysis. The softening behavior of the rock masses caused more deformations and yielded zones around the tunnels; the rock masses around the tunnels were observed to reach the residual strength values, which can be treated as failed areas. In addition, the M-C and s-s rock masses reacted differently as the K0 value changed. At K0=1.0, the tunnels seemed to be the most stable; K0=1.5, however, provided the worst scenario with roof and floor problems. With respect to the effectiveness of the support system, a large amount of the bonds of the supports was failing, thus, the deformations and yielded zones around the tunnels were slightly improved. Finally, comparisons between the numerical modeling results and the field measurements implied the applicability of strain softening behavior and a K0 value between 0.5 and 1.0 for the mine. Based on the specific geological, geotechnical, and construction information, a numerical model incorporating accurate features was developed. It includes a non-planar, weak interlayer, the persistent and non-persistent faults, and the open and backfilled excavations. The mechanical property values used for the rock masses and faults were estimated based on the laboratory test results of the intact rock and smooth joints. The strain softening behavior was specified for the rock masses belonging to the average quality, and the rock masses that reached residual strengths were assumed to be failing. The linear relations between the fault stiffnesses and normal stress were described using the continuously yielding joint model. To simulate the mine construction process in the field, the sequential excavation, backfilling, and supporting procedures were numerically implemented; additionally, a novel routine was applied to account for the delayed installation of the supports. Results showed that the tunnels close to the fault and the backfilled area were less stable. Most of the displacements around the tunnels occurred within a distance of zero to 2 or 3 m from the tunnel surface. The varying K0 value caused great changes in the rock mass behavior and the shear behavior of the major fault; significant instability of the tunnels was triggered by the high horizontal in situ stress. Parametric studies on the rock mass condition, rock mass residual strengths, and fault property values showed that the tunnel stability was more sensitive to the former two factors than the last one. A systematic investigation was conducted to evaluate the current rock supports installed at the mine where the increasing stress relaxation was incorporated. The deformations and of the failure zone thicknesses around the tunnels were reduced up to 8% and 20% after applying the supports instantaneously, and the reductions were improved by the delayed installation of supports. Additionally, the safety of supports was evaluated by the bond shear and bolt tensile failures, which was also improved with incorporation of delayed supporting. It was found that the current rock supports are insufficient in length, bond and tensile strengths. Therefore, a stronger support system was suggested. The stronger supports worked better in stabilizing the tunnels. Based on the deformations and failures of the rock masses, the length of the bolts on walls was suggested to be 4-5 m. At the end, the horizontal convergence strain predicted by the numerical simulations were calculated at two locations where the tape extensometers were installed. Good agreements with the field measurements were obtained for the cases that have the average rock mass properties and K0 values in the range 0.5-1.25.

Research carried out in several countries has concluded that high yielding varieties (HYV) of rice have tremendous potential compared to traditional rice varieties in alleviating poverty. On the other hand, it is argued that despite increase in yields, high yielding varieties do not benefit the poor farmers because of high costs associated with input acquisition and other operational costs. To further understand the issues related to production and economics of HYV, this study was carried out with its primary objective to assess the profitability of smallholder rice production in Mangol, Bilene district in southern Mozambique. Out of a total population of eighty farmers, sixty farmers participated in this research. Two groups of farmers, one using traditional rice varieties and the other using high yielding varieties were surveyed. The study consisted of field observations; yield measurements and interviews of the farmers using a semi-structured questionnaire. Gross margins were calculated for both traditional input users (TIU) and modem input users (MIU). Results show that an average farmer using high yielding varieties produces 4.4 tons of rice per ha, corresponding to a gross margin of 4 238 000,00 MZM. The highest yield obtained with high yielding varieties was 7.3 tons of rice per ha, producing a gross margin of 10 038 000,00 MZM. On the other hand, an average TIU farmer produces 2.5 tons per ha, realising a gross margin of 3 483 125, 00 MZM. The maximum yield attainable using traditional inputs is 2.9 tons per ha, producing a gross margin of 4 283 125, 00 MZM. The results also show that the lowest yield obtained by farmers using modern inputs was 3.1 tons per ha, producing gross margins of 1 638 000,00 MZM while the lowest attainable when using traditional inputs is 1.7 tons producing gross margins of 1 913 125,00 MZM. The main conclusion of this study was that HYV are more profitable than traditional varieties, both in financial terms, to individual farmer and in economic terms, to the society as a whole. However, due to high production costs, farmers producing HYV must attain yield levels not less than 3.4 tons per ha as yields below that level make little financial incentives and does not motivate farmers to shift from traditional varieties to modern varieties. In order to ensure high yields, farmers must be assisted to carefully implement the recommended agronomic practices because the adoption of high yielding varieties does not ensure profitable yields if the other agronomic and management practices are not observed during the production process. The study also assessed the contribution of agricultural support services such as input supply, credit and extension, on the adoption of new technologies and it was concluded that when agricultural support services are available, farmers can successfully adopt recommended technologies. / Dissertation (M Inst Agrar (Agricultural Economics))--University of Pretoria, 2006. / Agricultural Economics, Extension and Rural Development / unrestricted

No description available.

Since the introduction of motor vehicles, the number of fatalities and accidents has been a concern for society.The number of fatalities on roads is amongst the most common causes of mortality worldwide (WHO, 2015).Even in industrialized countries the number of fatalities remains unacceptable. Therefore, in the last decades, anumber of approaches have emerged to support and boost traffic safety towards a system free from fatalities andserious impairment outcomes. ‘Sustainable Safety’ and ‘Vision Zero’ are well-known examples aiming to avoidfatalities within the traffic system and reduce injury severity when a traffic accident is inevitable. However, thenumber of fatalities and seriously injured accidents are still relatively high. More specifically, vulnerable roadusers remain involved in fatal and serious accidents even in industrialized countries. Therefore, further advancesin traffic safety studies are needed. This thesis aims at evaluating the impact of road characteristics, traffic rulesand information provision towards a safer traffic system. The thesis is composed of five scientific papers whichsummarizes the main contributions of this work. / <p>QC 20161109</p>

The geological disposal of nuclear waste, in underground openings and the long-term performance of these openings demand a detailed understanding of fundamental rock mechanics. A full scale field experiment: Äspö Pillar Stability Experiment was conducted at a depth of 450 m in sparsely fractured granitic rock to examine the rock mass response between two deposition holes. An oval shaped tunnel was excavated parallel to the σ3 direction to provide access to the experiment and also provide elevated stress magnitudes in the floor. In the tunnel floor two 1.75-m diameter 6-m deep boreholes were excavated so that a 1-m thick pillar was created between them. In one of the holes a confinement pressure of 700 kPa was applied and in the other displacement transducers were installed. The pillar volume was monitored by an Acoustic Emission System. Spatially distributed thermocouples were used to monitor the temperature development as the pillar was heated by electrical heaters. The excavation-induced stress together with the thermal-induced stress was sufficient to cause the wall of the open borehole to yield. The temperature-induced stress was increased slowly to enable detailed studies of the rock mass yielding process. Once the rock mass loading response was observed, the rock mass was unloaded using a de-stress slotting technique. This thesis focuses on the in-situ study of the rock mass response to coupled mechanical thermal loading and thermal-mechanical unloading. The experiment, its design, monitoring and observations are thoroughly described. An estimate of the yielding strength of the rock mass is presented and compared with laboratory test and results from other rock mass conditions reported elsewhere in the open literature. General conclusions about the effect of the confining pressure and the observations from the unloading of the pillar are also presented. Important findings are that the yielding strength of the rock mass has been successfully determined, low confinement pressures significantly affects the onset of yielding, the primary mode of fracture initiation and propagation is extensional, no significant time dependency of the yielding process was observed. The unloading studies also indicated that what appeared to be shear bands likely was a propagating zone of extensile failure that weakened the rock so that displacements in the shear direction could occur. / <p>QC 20100622</p>

Current seismic design practice promotes inelastic response in order to reduce the design forces. By allowing the structure to yield while increasing the ductility of the structure, the global forces can be kept within the limited bounds dictated by the yield strength. However, during severe earthquakes, the structures undergo significant inelastic deformations leading to stiffness and strength degradation, increased interstory drifts, and damage with residual drift. The research presented in this thesis has three components that seek to address these challenges. To prevent the inelastic effects observed in yielding systems, a new concept “apparent weakening” is proposed and verified through shake table studies in this thesis. “Apparent weakening” is introduced in the structural system using a complementary “adaptive negative stiffness device” (NSD) that mimics "yielding” of the global system thus attracting it away from the main structural system. Unlike the concept of weakening and damping, where the main structural system strength is reduced, the new system does not alter the original structural system, but produces effects compatible with an early yielding. Response reduction using NSD is achieved in a two step sequence. First the NSD, which is capable of exhibiting nonlinear elastic stiffness, is developed based on the properties of the structure. This NSD is added to the structure resulting in reduction of the stiffness of the structure and NSD assembly or “apparent weakening”-thereby resulting in the reduction of the base shear of the assembly. Then a passive damper, designed for the assembly to reduce the displacements that are caused due to the “apparent weakening”, is added to the structure-thereby reducing the base shear, acceleration and displacement in a two step process. The primary focus of this thesis is to analyze and experimentally verify the response reduction attributes of NSD in (a) elastic structural systems (b) yielding systems and (3) multistory structures. Experimental studies on 1:3 scale three-story frame structure have confirmed that consistent reductions in displacements, accelerations and base shear can be achieved in an elastic structure and bilinear inelastic structure by adding the NSD and viscous fluid damper. It has also been demonstrated that the stiffening in NSD will prevent the structure from collapsing. Analogous to the inelastic design, the acceleration and base shear and deformation of the structure and NSD assembly can be reduced by more than 20% for moderate ground motions and the collapse of structure can be prevented for severe ground motions. Simulation studies have been carried on an inelastic multistoried shear building to demonstrate the effectiveness of placing NSDs and dampers at multiple locations along the height of the building; referred to as “distributed isolation”. The results reported in this study have demonstrated that by placing a NSD in a particular story the superstructure above that story can be isolated from the effects of ground motion. Since the NSDs in the bottom floors will undergo large deformations, a generalized scheme to incorporate NSDs with different force deformation behavior in each storey is proposed. The properties of NSD are varied to minimize the localized inter-story deformation and distribute it evenly along the height of the building. Additionally, two semi-active approaches have also been proposed to improve the performance of NSD in yielding structures and also adapt to varying structure properties in real time. The second component of this thesis deals with development of a novel device to control the response of structural system using adaptive length pendulum smart tuned mass damper (ALP-STMD). A mechanism to achieve the variable pendulum length is developed using shape memory alloy wire actuator. ALP-STMD acts as a vibration absorber and since the length is tuned to match the instantaneous frequency, using a STFT algorithm, all the vibrations pertaining to the dominant frequency are absorbed. ALP-STMD is capable of absorbing all the energy pertaining to the tuned-frequency of the system; the performance is experimentally verified for forced vibration (stationary and non-stationary) and free vibration. The third component of this thesis covers the development of an adaptive control algorithm to compensate hysteresis in hysteretic systems. Hysteretic system with variable stiffness hysteresis is represented as a quasi-linear parameter varying (LPV) system and a gain scheduled controller is designed for the quasi-LPV system using linear matrix inequalities approach. Designed controller is scheduled based on two parameters: linear time-varying stiffness (slow varying parameter) and the stiffness of friction hysteresis (fast varying parameter). The effectiveness of the proposed controller is demonstrated through numerical studies by comparing the proposed controller with fixed robust H∞ controller. Superior tracking performance of the LPV-GS over the robust H∞ controller in different displacement ranges and various stiffness switching cases is clearly evident from the results presented in this thesis. The LPV-GS controller is capable of adapting to the parameter changes and is effective over the entire range of parameter variations.

O modelo cam-clay modificado foi aplicado aos resultados experimentais obtidos para um solo arenoso típico da cidade de São Carlos. Os ensaios de compressão triaxial foram conduzidos em equipamento moderno, com instrumentação interna, segundo distintas trajetórias de carregamento. Verificou-se que os resultados obtidos em termos de modelagem foram satisfatórios, principalmente quando a tensão octaédrica (p\') foi diminuida durante os carregamentos. Nesse caso, tanto em termos de modelagem como de resultados experimentais, houve expansão de volume do solo. Com o aumento da tensão octaédrica, verificou-se a ocorrência de compressão volumétrica do solo. Observou-se que o modelo apresenta uma previsão de deformações axiais maiores do que as observadas experimentalmente nas trajetórias de -30, -50, 30, 40, 50, 60, 120 graus e no ensaio triaxial convencional com \'sigma\' 3 = 100 kPa. Além disso, determinou-se a superfície inicial de plastificação do solo utilizando-se dois critérios que tenderam a fornecer valores de tensão de cedência aproximadamente iguais, notando-se que a condição de fluxo associado não é obedecida. / The modified cam-clay model was used to model experimental results of a sandy soil from São Carlos - SP. Triaxial compression tests were performed using Bishop - Wesley cell with internal transducers to measure axial and radial strains. It was observed that the model fairly fitted experimental results, specially when medium effective stress (p\') is reduced during loading. In this case, both the model and the experimental results, showed volume increase. When (p\') increases the model and the tests showed a tendency to give volumetric compression, although the values were differents. The model yielded strains larger than that measured in the tests when the stress-paths were of -30, -50, 30, 40, 50, 60, 120 degrees and in axial compression test with 100 kPa of confining pressure. Besides that, initial yield surface of soil was calculated from test results using two different criteria which gave about the same yield stress and it is show that normality rule was not satisfied in this soil.

O modelo cam-clay modificado foi aplicado aos resultados experimentais obtidos para um solo arenoso típico da cidade de São Carlos. Os ensaios de compressão triaxial foram conduzidos em equipamento moderno, com instrumentação interna, segundo distintas trajetórias de carregamento. Verificou-se que os resultados obtidos em termos de modelagem foram satisfatórios, principalmente quando a tensão octaédrica (p\') foi diminuida durante os carregamentos. Nesse caso, tanto em termos de modelagem como de resultados experimentais, houve expansão de volume do solo. Com o aumento da tensão octaédrica, verificou-se a ocorrência de compressão volumétrica do solo. Observou-se que o modelo apresenta uma previsão de deformações axiais maiores do que as observadas experimentalmente nas trajetórias de -30, -50, 30, 40, 50, 60, 120 graus e no ensaio triaxial convencional com \'sigma\' 3 = 100 kPa. Além disso, determinou-se a superfície inicial de plastificação do solo utilizando-se dois critérios que tenderam a fornecer valores de tensão de cedência aproximadamente iguais, notando-se que a condição de fluxo associado não é obedecida. / The modified cam-clay model was used to model experimental results of a sandy soil from São Carlos - SP. Triaxial compression tests were performed using Bishop - Wesley cell with internal transducers to measure axial and radial strains. It was observed that the model fairly fitted experimental results, specially when medium effective stress (p\') is reduced during loading. In this case, both the model and the experimental results, showed volume increase. When (p\') increases the model and the tests showed a tendency to give volumetric compression, although the values were differents. The model yielded strains larger than that measured in the tests when the stress-paths were of -30, -50, 30, 40, 50, 60, 120 degrees and in axial compression test with 100 kPa of confining pressure. Besides that, initial yield surface of soil was calculated from test results using two different criteria which gave about the same yield stress and it is show that normality rule was not satisfied in this soil.