Occupational exoskeletons are designed to reduce workplace injury risk by decreasing work demands. Due to their relatively recent development, there has been limited research into potential unintended and undesirable consequences of wearing them. The goal of this thesis was to investigate the effects of exoskeleton use on reactive balance in response to simulated slips and trips. Five representative exoskeletons were investigated including leg-, back, and shoulder-support exoskeletons. This thesis consists of two studies: a smaller study investigating one exoskeleton and a larger one investigating multiple exoskeletons. Participants stood on a specialized treadmill, then abruptly and unexpectedly changing treadmill belt speed to simulate trip-like forward losses of balance or slip-like backward losses of balance. The results of the first study showed that a passive leg-support exoskeleton adversely reactive balance for both slips and trips. The results of the second study showed that back-support exoskeletons had a greater adverse effect on reactive balance compared to shoulder-support exoskeletons for both slips and trips. These exoskeletons affected reactive balance due to their interaction with stepping kinematics and movement constraints. This thesis provides important information that can be used to warn users of potential increased fall risks and inform exoskeleton manufacturers who may be able to modify designs to reduce any additional fall risk. / Master of Science / Occupational exoskeletons reduce muscle workload for workers during manual tasks. However, because of their additional weight and how they restrict movement, they can increase the risk of falling after a slip or a trip. The goal of this thesis was to see how exoskeletons affect balance after simulated slips and trips. Five exoskeletons were studied; These exoskeletons supported the legs, back, and shoulders. This thesis includes two studies: a smaller study with one exoskeleton and a larger one with multiple exoskeletons. In order to simulate a slip and trip, participants stood on a treadmill and then the treads would unexpectedly accelerate to a speed to make them lose their balance. The results of the first study showed that an exoskeleton that supported the legs negatively affected balance for both slips and trips. The results of the second study showed that exoskeletons that supported the back negatively affected balance more than those that supported the shoulders for both slips and trips. These exoskeletons affected balance due to them interacting with the legs and affected stepping. This thesis provides important information that can be used to warn workers of potential increased fall risks and inform exoskeleton manufacturers who may be able to help reduce any fall risk.

Nowadays, the increasing amount of greenhouse gases and diminishing of the existing petroleum minerals for future generations, has led the automotive companies to think of producing vehicles with less emissions and fuel consumption. For this purpose, Hybrid Electric Vehicles (HEVs) have emerged in the recent decades. HEVs with different configurations have been introduced by engineers.The simulation platform aim for a parallel HEV, where the intention is to reduce the emissions and fuel consumption. The simulation platform includes an Electric Motor (EM) in addition to an Internal Combustion Engine (ICE). A new transmission system is modeled which is compatible with parallel configuration for the HEV, where the inertial effects of the gearbox, clutch and driveline is formulated. The transmission system includes a gearbox which is equipped with synchronizers for smooth change of gears. The HEV is controlled by a rule based controller together with an optimization algorithm as power management strategy in order to have optimal fuel consumption. Using the rule based controller, the HEV is planned to be launched by EM in order to have a downsized clutch and ICE. The clutch modeling is the main focus of this study, where the slipping mechanism is considered in the simulation. In the driveline model, the flexibility effects of the propeller shaft and drive shaft is simulated, so that the model can capture the torsional vibrations of the driveline. The objective of modeling such a system is to reduce emissions and fuel consumption with the same performance of the conventional vehicle. To achieve this goal first a conventional vehicle is modeled and subsequently, a hybrid vehicle is modeled and finally the characteristics of the two simulated models are studied and compared with each other. Using the simulation platform, the state of charge (SOC) of the battery, oscillations of propeller shaft and drive shaft, clutch actuations and couplings, energy dissipated by the clutch, torques provided by EM and ICE, fuel consumptions, emissions and calculation time are calculated and investigated. The hybridization results in a reduction in fuel consumption and emissions, moreover, the energy dissipated by the clutch and clutch couplings are decreased.

nÃo hà / Objetivou-se com esse ensaio avaliar o desempenho energÃtico de um microtrator agrÃcola Yanmar Agritech modelo NSB14S, com potencia nominal de 10,3 kW (14 cv) submetido a trÃs diferentes relaÃÃes peso/potencia, 0,41; 0,54 e 0,67 kN kW-1 (41, 54 e 67 kgf kW-1) em trÃs superfÃcies de rolamento (concreto, solo firme e solo mobilizado). O ensaio foi realizado em trÃs superfÃcies de rolamento, uma pista de concreto para ensaios de maquinas agrÃcolas, pista de solo agrÃcola firme e pista de solo agrÃcola mobilizado. Para obtenÃÃo de dados sobre a eficiÃncia energÃtica, instrumentou-se o microtrator com sensores indutivos nas rodas para medir a patinagem dos rodados, medidores volumÃtricos de consumo de combustÃvel e cÃlula de carga para obtenÃÃo da forÃa de trabalho na barra de traÃÃo. Foi utilizado o delineamento experimental em faixa. Em cada pista foram dispostos os tratamentos com um arranjo fatorial de 3x3, com 6 repetiÃÃes por faixa, totalizando 54 unidades experimentais, todos os dados foram submetidos à analise de variÃncia, aplicado o teste de Tukey a 5% de significÃncia, para a comparaÃÃo das medidas. Todas as anÃlises estatÃsticas foram realizadas com o auxÃlio do software ASSISTAT VersÃo 7.6 beta (2012) da Universidade Federal de Campina Grande. As variÃveis velocidade de deslocamento (km h-1), patinagem (%), potÃncia disponÃvel na barra de traÃÃo (kW) e rendimento na barra de traÃÃo (%),apresentaram interaÃÃo significativa, entretanto as variÃveis forÃa de traÃÃo na barra (kN), consumo horÃrio de combustÃvel (L h-1) e consumo especÃfico de combustÃvel (g.kWh-1), os mesmos apresentaram efeito significativo apenas no fator de variaÃÃo superfÃcie de rolamento. Na condiÃÃo de relaÃÃo peso/potÃncia 41 kgf kW-1, apresentou maiores Ãndices de patinagem e velocidade de deslocamento ambas em superfÃcie mobilizada. O consumo de combustÃvel apresentou menores valores na superfÃcie de concreto, jà para consumo especifico de combustÃvel a superfÃcie de solo mobilizada apresentou melhor conversÃo energÃtica, como tambÃm melhore forÃa na barra de traÃÃo. Os rendimentos na barra de traÃÃo estÃo abaixo do proposto pela ASAE. / The objective of this test is evaluate the energy performance of an agricultural microtractor Yanmar Agritech  model NSB14S with nominal power of 10.3 kW (14 hp) under three different weight / power ratios, 0.41, 0.54 and 0,67 kN kW-1 (41, 54 e 67 kgf kW-1) in three roller surface (concrete, firm soil and soil disturbed). The assay was performed on three roller surface, a concrete track for testing agricultural machinery, agricultural soil firm track and agricultural mobilized soil track. To obtain data on energy efficiency, the microtractor was instrumented with inductive sensors in the wheels to measure the slipping wheelset, volumetric meters of fuel consumption and load cell for the workforce to the drawbar. The experimental design was used on track. In each lane were disposed the treatments with a factorial arrangement of 3x3, with 6 replicates per lane, totaling 54 experimental units, all data were subjected to analysis of variance, applied the Tukey test at 5% significance for the comparison of measurements. All statistical analyzes were performed with the aid of software ASSISTAT Version 7.6 beta (2012) by Federal University of Campina Grande. The variable displacement speed (km h-1), slipping (%), available power on drawbar (kW) and yield on the drawbar (%), showed a significant interaction, however the variables traction force on drawbar (kN), hourly fuel consumption (L h-1) and specific fuel consumption (g.kWh-1), they had a significant effect only on the variation factor roller surface. Provided that the rate weight/power 41 kW kgf-1, showed higher index of slipping and displacement speed both in mobilized surface. The fuel consumption had showed lower values on concrete surface, to specific fuel consumption the mobilized soil surface showed better energy conversion, as well as improve power on the drawbar. Yields on the drawbar are below the proposed by ASAE.

Thoracic joints, like many other osteological articulations of the human body, are prone to arthritic pathologies caused by physical trauma, autoinflammatory diseases, or connective tissue disorders. Costochondral disorders are particularly problematic because the associated clinical symptoms are analogous to those of pleural, cardiac, and intraperitoneal disorders, resulting in an increased frequency of misdiagnosis. The four most prominent costochondral disorders, according to the medical literature, are Costochondritis, Tietze syndrome, Slipping Rib Syndrome, and Rib Tip Syndrome. This study utilizes a broad library of published research to examine the etiology and diagnosis of these disorders with an emphasis on distinguishing the most effective and practical treatments.

No description available.

Today construction industry is building higher and more complicated constructions than ever thanks to the advancements in materials, technical knowledge and methodologies. One important material is concrete, which has been used to create impressive architectural marvels. This dissertation aims to examine the differences between climbing and slip formwork systems for tall concrete structures that require several pouring steps in height. The main differences noted between both systems are formwork configuration, assembly and cycling of the formwork and climbing elements, price and quantity of material, labor required, the quality of the finished structure and safety during construction. A case study was investigated with the help of formwork supplier PERI Sverige AB and nordic contractor PEAB AB regarding a 20,5 meter high reinforced concrete silo located in a mining complex in Kiruna, Sweden. Through a review of the existing literature in the subject, interviews with experts in the topic and the outcome from the project case study, the results shows that while the SCS climbing system from PERI Sverige AB required more working days compared to a slip formwork system, it was chosen as a more appropriate solution for this project in combination with the crane at the jobsite, due to the amount of labor required, safety and overall cost of it. In conclusion, the selection of the SCS climbing system as formwork system proved to be the most adequate solution for the case study when critical aspects such as assembly and cycling of formwork, price and safety were evaluated.

No description available.

Este trabalho busca aplicar técnicas de confiabilidade ao problema de grupo de estacas utilizadas como fundação de estruturas correntes. Para isso, lança-se mão de um modelo tridimensional de interação estaca-solo onde estão presentes o Método dos Elementos de Contorno (MEC) e o método dos Elementos Finitos (MEF) que atuam de forma acoplada. O MEC, com as soluções fundamentais de Mindlin (meio semi-infinito, homogêneo, isotrópico e elástico-linear é utiliza), é utilizado para modelar o solo. Já o MEF é utilizado para modelar as estacas. Definido o modelo de funcionamento estrutural das estacas, parte-se para a aplicação de métodos trazidos da confiabilidade estrutural para avaliação da adequabilidade em relação aos estados limite de serviço e estados limites últimos. Os métodos de confiabilidade utilizados foram o Método de Monte Carlo, o método FOSM (First-Order Second-Moment) e o método FORM (First-Order Reliability Method). / This work seeks to apply reliability techniques to the problem of piles groups used as current structures foundation. For this, makes use of a three-dimensional model of pile-soil interaction with the boundary element method (BEM) and the finite element method (FEM) working coupled. The BEM, with Mindlin fundamental solutions (semi-infinite medium, homogeneous, isotropic and linear elastic) is used to model the soil. The MEF is used to model the piles. Defined the model of structural functioning of the piles, the aim goes to the application of structural reliability for assessing the adequacy of the serviceability limit states and ultimate limit states. Reliability methods used were the Monte Carlo method, the FOSM (First-Order Second-Moment) method and the FORM method (First-Order Reliability Method).

A captação de energia eólica tem sido alvo de estudos em todo o mundo nas últimas décadas devido aos incentivos pela busca por geração de energia por meio de fontes alternativas. A configuração mais utilizada atualmente são as turbinas de três pás com eixo horizontal, upwind, operando com velocidade variável com limitação de potência por variação de passo, e utilizando o gerador de indução de dupla alimentação. A operação em velocidade variável com atuação no ângulo de passo permite a máxima captação de energia para as diferentes velocidades de vento, enquanto evita que a turbina ultrapasse o seu valor nominal de potência. O uso de conversores permite o controle das correntes do rotor, variando sua velocidade, e o controle da potência reativa de estator, e a montagem do tipo back-to-back permite que o fluxo de energia do rotor flua para a rede ou da rede. A modelagem matemática do sistema foi toda referenciada no referencial síncrono com notação vetorial e orientação de fluxo de rede, simplificando os modelos matemáticos. Para a montagem dos controladores foi utilizado o método de Controle de Modelo Interno e de Resistência Ativa. A montagem de todo o sistema para simulação foi realizada no Matlab/Simulink, e seu desenvolvimento é mostrado no decorrer do trabalho. Este trabalho analisa o fluxo de energia do sistema, desde a energia captada pelo vento até a energia entregue à rede. Para isso, são feitas análise dos fluxos das potências ativa e reativa do sistema, para fator de potência unitário, indutivo e capacitivo e para os mais recorrentes comportamentos do vento. Também são feitas análises a respeito dos regimes de operação do sistema, definidos a partir da relação entre os fluxos de potência, concluindo que a máquina poderá operar como gerador ou motor, devido principalmente à intensidade da variação do vento. / The use of wind energy has been the subject of studies around the world in recent decades due to the incentives to search for power generation through alternative sources. The most widely used configuration has been the three blades with horizontal axis and upwind turbine, operating in variable speed with power limitation by varying the pitch angle, and using the doubly fed induction generator configuration. The variable speed operation with power limitation enable for maximum energy harvesting for different wind speeds and prevents the turbine exceeds its nominal power. The use of converters allows for control of the rotor currents, varying the speed, and stator reactive power, and assembling type back-to-back allows for the rotor energy flux to flow into and out of the grid. Mathematical modeling of the whole system was referenced in the synchronous reference frame with vector notation and oriented by the grid flux, simplifying the mathematical models. For installation of the drivers, were used the Internal Model Control and Active Damping methods. The assembly of the entire system for simulation was conducted on Matlab / Simulink, and its step to step is shown in this work. This study analyzes the energy flow of the system, from the energy harvest from de wind to the energy delivered to the grid. To reach this, flow analysis of active and reactive power of the system is done, using unity, inductive and capacitive power factor, for the most recurrent wind behaviors. Analysis are made about the operation regimes of the system, defined as the relationship between the power flows, concluding that the machine can operate as a generator or motor, mainly due to the variation of the wind intensity.

A captação de energia eólica tem sido alvo de estudos em todo o mundo nas últimas décadas devido aos incentivos pela busca por geração de energia por meio de fontes alternativas. A configuração mais utilizada atualmente são as turbinas de três pás com eixo horizontal, upwind, operando com velocidade variável com limitação de potência por variação de passo, e utilizando o gerador de indução de dupla alimentação. A operação em velocidade variável com atuação no ângulo de passo permite a máxima captação de energia para as diferentes velocidades de vento, enquanto evita que a turbina ultrapasse o seu valor nominal de potência. O uso de conversores permite o controle das correntes do rotor, variando sua velocidade, e o controle da potência reativa de estator, e a montagem do tipo back-to-back permite que o fluxo de energia do rotor flua para a rede ou da rede. A modelagem matemática do sistema foi toda referenciada no referencial síncrono com notação vetorial e orientação de fluxo de rede, simplificando os modelos matemáticos. Para a montagem dos controladores foi utilizado o método de Controle de Modelo Interno e de Resistência Ativa. A montagem de todo o sistema para simulação foi realizada no Matlab/Simulink, e seu desenvolvimento é mostrado no decorrer do trabalho. Este trabalho analisa o fluxo de energia do sistema, desde a energia captada pelo vento até a energia entregue à rede. Para isso, são feitas análise dos fluxos das potências ativa e reativa do sistema, para fator de potência unitário, indutivo e capacitivo e para os mais recorrentes comportamentos do vento. Também são feitas análises a respeito dos regimes de operação do sistema, definidos a partir da relação entre os fluxos de potência, concluindo que a máquina poderá operar como gerador ou motor, devido principalmente à intensidade da variação do vento. / The use of wind energy has been the subject of studies around the world in recent decades due to the incentives to search for power generation through alternative sources. The most widely used configuration has been the three blades with horizontal axis and upwind turbine, operating in variable speed with power limitation by varying the pitch angle, and using the doubly fed induction generator configuration. The variable speed operation with power limitation enable for maximum energy harvesting for different wind speeds and prevents the turbine exceeds its nominal power. The use of converters allows for control of the rotor currents, varying the speed, and stator reactive power, and assembling type back-to-back allows for the rotor energy flux to flow into and out of the grid. Mathematical modeling of the whole system was referenced in the synchronous reference frame with vector notation and oriented by the grid flux, simplifying the mathematical models. For installation of the drivers, were used the Internal Model Control and Active Damping methods. The assembly of the entire system for simulation was conducted on Matlab / Simulink, and its step to step is shown in this work. This study analyzes the energy flow of the system, from the energy harvest from de wind to the energy delivered to the grid. To reach this, flow analysis of active and reactive power of the system is done, using unity, inductive and capacitive power factor, for the most recurrent wind behaviors. Analysis are made about the operation regimes of the system, defined as the relationship between the power flows, concluding that the machine can operate as a generator or motor, mainly due to the variation of the wind intensity.