Cross median crashes have become a serious problem in recent years. Most of the median cross sections used for divided highways have terrains with steep slopes. Traffic barriers, frequently used on slopes, are generally designed based on the findings obtained from crash tests performed on flat terrain. For barriers placed on roadside and median slopes, vehicle impact height varies depending on the trajectory of the vehicle along the ditch section and lateral offset of the barrier. Thus depending on the placement location on a relatively steep slope, a barrier can be impacted by an errant vehicle at height and orientation more critical compared to those considered during its design. Hence, detailed study of performance of barriers on roadside and median slopes is needed to achieve acceptable safety performance. In this study, performances of modified G4(1S) W-beam, Midwest Guardrail System (MGS), modified Thrie-beam, modified weak post W-beam, and box-beam guardrail systems on sloped terrains are investigated using numerical simulations. A procedure is developed that provide guidance for their placement on roadside and median slopes. The research approach consists of nonlinear finite element analyses and multi-rigid-body dynamic analyses approach. Detailed finite element representation for each of the barriers is developed using LS-DYNA. Model fidelity is assessed through comparison of simulated and measured responses reported in full scale crash test studies conducted on flat terrain. LS-DYNA simulations of vehicle impacts on barriers placed on flat terrain at different impact heights are performed to identify performance limits of the barriers in terms of acceptable vehicle impact heights. The performances of the barriers are evaluated following the guidelines provided in NCHRP Report 350. Multi-rigid-body dynamic analysis code, CARSIM, is used to identify trajectories of the vehicles traversing various roadside and median cross-slopes. After analyzing vehicle trajectories and barrier performance limits, a guideline has been prepared with recommendations for the placement of barriers along roadside and median slopes. This guideline is then verified and refined using the responses obtained from full-scale LS-DYNA simulations. These simulations capture the full encroachment event from departure of the vehicle off the traveled way through impact with the barrier.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This Master s Dissertation presents the development of a methodology for performance assessment and establishment of limits of power supply continuity using Fuzzy Logic, including the processes of selecting variables that characterizethe problemand determiningadjustments tothe limitsof thecontinuity indexes. The studybegins withextensive researchto selectvariablesthat most closely characterize the reliability problem ofpower distributionnetworks. After this selection,the systemis divided intotwo levels of assessment. At the first level, the variables are grouped intothreeindependent systems defining indexes that evaluatenetwork reliabilitydue tooperational characteristics, the quality of networksand the influenceof the environment. At the second level, these indexesare evaluatedon a new systemtogether with thehistorical performanceof consumer sets, from where adjustmentsare obtained and applied to the limitsof power supply continuity established by ANEEL (Regulatory Agency). DatafromtheState CompanyofElectric Power Distribution(CEEE-D) is applied and the results of the developed system are evaluated. From the resultsobtained, it becomes possible to identifyand proposeadjustmentsto the limits ofperformanceand to definepriority targets foractions aimed at to improving thequality ofpower supply. / Esta dissertação apresenta o desenvolvimento de uma metodologia de avaliação de desempenho e de definição de limites de continuidade de fornecimento de energia elétrica usando a Lógica Fuzzy, compreendendo desde o processo de seleção das variáveis que caracterizam o problema até o processo de determinação de ajustes para os limites dos indicadores de continuidade. O trabalho inicia-se com uma vasta pesquisa para selecionar as variáveis, visando caracterizar o problema de confiabilidade das redes de distribuição de energia da melhor forma possível. Após a seleção, o sistema é dividido em dois níveis de avaliação.No primeiro nível, as variáveis são agrupadas em três sistemas independentes, os quais definem índices que avaliam confiabilidade da rede devido a características operacionais, o padrão de rede e a influência do meio. No segundo nível, esses índices são avaliados juntamente com o histórico de desempenho dos conjuntos de consumidores de forma que sejam definidos ajustes para os limites de continuidade de fornecimento de energia. Dados da Companhia Estadual de Distribuição de Energia Elétrica (CEEE-D) são utilizados e os resultados obtidos a partir do sistema desenvolvido são avaliados.A partir dessa análise, torna-se possível identificar e propor adequações aos limites de desempenho, bem como definir conjuntos prioritários para ações de melhoria na qualidade do fornecimento de energia.

Growing concerns about interruption to oil supply and oil shortages have led to escalating global oil prices. In addition, increased public acceptance of the global warming problem has prompted car manufacturers to agree to carbon emission targets in many regions including most recently, the Californian standards. Other legislating bodies are sure to follow this lead with increasingly stringent targets. As a result of these issues, spark ignition engines in their current form will need significant improvements to meet future requirements. One technically feasible option is smaller capacity downsized engines with enhanced power that could be used in the near term to reduce both carbon emissions and fuel consumption in passenger vehicles.This research focuses on exploring the performance limits of a 0.43 liter spark ignited engine and defining its operating boundaries. Limiting factors such as combustion, gas exchange and component design are investigated to determine if they restrict small engine performance. The research gives direction to the development of smaller gasoline engines and establishes the extent to which they can contribute to future powertrain fuel consumption reduction whilst maintaining engine power at European intermediate class requirements.

The analytical tools used in displacement based design and assessment procedures require accurate strain limits to define the performance levels. Additionally, recently proposed changes to modeling and acceptance criteria in seismic regulations for both flexure and shear dominated reinforced concrete structural walls proves that a comprehensive study is required for improved limit state definitions and their corresponding values. This is due to limitations in the experimental setups, such that most previous tests used a single actuator at the top of the wall, which does not reflect the actual loading condition, and infeasibility of performing tests of walls of actual size in actual structural configuration. This study utilizes a well calibrated finite element modeling tool to investigate the relationship between the global drift, section rotation and curvature, and local concrete and steel strains at the extreme fiber of rectangular structural walls. Functions defining more exact limits of modeling parameters and acceptance criteria for rectangular reinforced concrete walls were developed. This way a strict evaluation of the requirements embedded in the Turkish Seismic Code and other design guidelines has become possible. Several other aspects of performance evaluation of structural walls were studied also. Accurate finite element modeling strategies and analytical models of wall and frame-wall systems were developed for seismic response calculations. The models are able to calculate both the static and dynamic characteristics of wall type buildings efficiently. Seismic responses of wall type buildings characterized with increasing wall area in the plan were analyzed under design spectrum compatible normal ground motions.

Antenna implants are used to establish a telemetry link to enable wireless data transfer, suitable for telemedicine and other medical applications. Inbody environments with water-based tissues lead to severe power absorption, making signal strength and radiation efficiency challenging yet central performance aspects of antenna implants. Fundamental performance limits exist regarding radiation efficiency; however, these limits consider theoretically ideal Hertzian dipoles. A semi-analytical model is used to evaluate the feasibility of previously determined fundamental bounds and the optimal dipole solution, both with respect to physical necessities of finite material conductivity and antenna size. This study uses a spherical model to represent a simplified in-body environment with various phantom compositions. Furthermore, the study focuses on implants operating within the Medical Implant Communication System (MICS) frequency band, but models and methods are not restricted to the considered frequency. The work contributes to the field of implantable antennas in several aspects; evaluating the feasibility of fundamental bounds, establishing more realistic performance limits, and determining the optimal dipole solution with respect to radiation efficiency. Other findings are presented in related areas, particularly concerning conductor loss and evaluation of the impedance for antennas inside a high-loss phantom. Moreover, the work presents a suggested method to measure electrically small magnetic dipole antennas. Methods and models are documented in a substantial theoretical derivation, and findings are verified using independent methods. Neglecting necessary antenna aspects like finite size and conductivity can lead to faulty conclusions on implant performance. Providing a more realistic performance target helps predict the performance of realistic antenna designs. Ultimately, increased knowledge of implanted antennas simplifies the design process to achieve high-performance implants. / Antennimplant används för att etablera en telemetrilänk som möjliggör trådlös dataöverföring, exempelvis användbart inom telemedicin och andra medicinska tillämpningar. Vattenbaserade kroppsmiljöer resulterar i kraftig absorption, vilket implicerar att signalstyrka samt strålningseffektivit blir utmanande men även centrala prestanda egenskaper för antennimplnatat. Det existerar fundamentala prestandabegränsningar för strålningseffektivitet, men dessa gränser är etablerade med hänsyn till teoretiskt ideala elementära dipoler. En semi-analytisk modell används för att utvärdera rimligheten av tidigare begränsningar samt den optimala dipolen, bägge med hänsyn till nödvändiga aspekter som ändlig konduktivitet och antennstorlek. Denna studie använder en sfärisk modell för att representera en simplifierad kroppslig miljö med olika vävnadskompositioner. Studien fokuserar på antennimplantat inom frekvensbandet dedikerat för Medical Implant Communication System (MICS) enheter, men modeller och metoder är typiskt inte begränsade inom omnämnt band. Arbetet bidrar till området för implanterbara antenner i flera aspekter; att utvärdera rimligheten av fundamentala gränser, fastställa mer realistiska prestandagränser samt bestämma den optimala dipolen med avseende på strålningseffektivitet. Andra resultat presenteras inom relaterade aspekter som metallförlust och utvärdering av en antenns last eller ingångs impedans inuti sfäriska och kroppsliga miljöer. Dessutom presenteras en metod för att mäta elektriskt små magnetiska dipoler. Metoder och modeller är dokumenterade eller demonstrerade via härledning, och centrala resultat har verifieras med oberoende metoder. Att förbise nödvändiga aspekter som ändlig storlek och konduktivitet kan leda till felaktiga slutsatser gällande prestanda. Däremot, att fastställa en mer realistisk gräns bidrar till att förutsäga prestandan i realistiska tillämpningar. I slutändan så resulterar ökad kunskap i en simplifierad designprocess som underlättar i strävan till att uppnå högpresterande antennimplantat.