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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

A Preliminary Study for Estimating Postmortem Interval of Fabric Degradation in Central Florida

Humbert, Lorraine L. 01 December 2013 (has links)
Forensic anthropologists rely on forensic evidence to estimate the postmortem interval of a decedent. This may include the study of the degree of deterioration of the human body, the life stage of insects, and the degradation of associated material evidence. Material evidence comes in many forms, and certain taphonomic processes will affect the material and must be considered when making inferences about a PMI. These include variables such as the characteristics of the soil, microorganisms, and the presence of a decaying organic material. Previous research has undertaken studies in how fabric degrades over time; however, there is no standard methodology in use. The purpose of this research project is to establish a comprehensive scoring system and description standard after analyzing the degradation of four different fabric types. This will be useful for future studies in need of a standard methodology. In addition, the methods used in this project can be applied to actual forensic cases. After retrieval, the fabric type with the highest degradation was the cotton with about 1/3 of all cotton fabric swatches demonstrating more than 50% total degradation. For all fabric types, swatches that were positioned flat tended to degrade more than those that were positioned crumpled. Cotton fabric swatches degraded more in Trench 1 and Trench 2 than the Ground Surface, however, all other fabric types demonstrated slightly more degradation on the Ground Surface than the other two Areas. Soil moisture fluctuated the most on the Ground Surface while Trench 1 and Trench 2 were able to retain more water in the soil. Overall, cotton was the only fabric type to degrade significantly enough to show how it degrades over time, while the other fabric types have longer degradation intervals that must be studied further.
2

[en] TIME TO DIGITAL CONVERTER / [pt] CONVERSOR TEMPO-DIGITAL

ANA LUCIA CAPECHI DE PINHO 08 November 2005 (has links)
[pt] É apresentado um projeto para desenvolvimento de um conversor tempo-digital. O projeto baseia-se no uso de um oscilador como clock de referência, acoplado a uma linha de retardo composta por células de retardo discretas. O retardo total da linha é igual ao período do oscilador, de modo que a cada ciclo apenas um pulso se propaga através da linha. A medida de intervalos de tempo é composta pelo registro da contagem do número de pulsos do oscilador durante o intervalo, mas uma estimativa fina obtida a partir da posição do pulso na linha de retardo no momento de incidência dos sinais delimitadores do intervalo medido. Um estudo detalhado da linha de retardo é mostrado, indicando sua aplicabilidade para a tarefa em questão. Deste estudo fica clara a necessidade de se prever um circuito de acionamento (driver) que realize a interface entre a linha de retardo e os circuitos digitais. Este drive é projetado e testado. Simulações do circuito completo (oscilador, linha reta de retardo, drivers, registrador, codificador e contador) são feitas, demostrando a viabilidade do projeto. Para a implementação do conversor, foram utilizadas uma placa de circuito impresso com quatro camadas e uma interface de aquisição de dados. / [en] It is present a project to develop a Time to Digital Converter. Project is based on use of a oscillator as a clock coupled to a delay line compound by delay cells. The total delay line is equal to the period of oscillator, such for each eycle only a pulse cross the line. Measure of these intervals of time is compound by recording the numbers of oscillators pulses during these intervals, added to a fine estimation from the interval. A detailed study of delay line is showed, indicating its is applicable. It is already important to project a driver that realizes the interface between delay line and the others digital circuits. This driver is projected and tested. Complete circuit is simulated, (oscillator, delay line, register, encoder and counter), showing that project is applicable. A printed board crcuit with four layers and a interface for processing data were developed.
3

Operation planning for power grids with high instalment of dynamically rated components in liberalised electricity markets

Lundquist, Frida January 2022 (has links)
The power grid is a complex system that requires detailed planning and operation of the power sources. As renewable resources are increasing their share of the power mix, there are new criterion and aspects to take into account. Renewable resources such as wind and solar power are intermittent and challenge the planning and operation further. Simultaneously, the power demand increases and will continue to increase in the future. As the power resources and demand are changing in the power system, the power grid needs to adapt and be more flexible. A flexibility tool for the power system is Dynamic Rating which can dynamically increase the capacity in the power grid components depending on the environmental conditions. This can enable for higher transmission in overhead lines which facilitates the operation planning of power units. Dynamic rating can be applied to various power system components, but the focus in this project is Dynamic Line Rating (DLR). It is interesting to study the implementation of dynamic rating in the realtime market. The real-time market optimal power flow can be done in singleinterval or multi-interval. In this project, dynamic rating is implemented into multi-interval real-time market optimal power flow to investigate the effect on the generation costs. The results indicate that DLR can reduce the generation costs in power grids that are sometimes congested. / Kraftnätet är ett komplext system som kräver detaljerad planering och verksamhet av energikällor. Allt eftersom andelen förnybara energikällor ökar tillkommer nya aspekter att ta hänsyn till. Förnybara energikällor såsom vindkraft och solenergi har en mer ojämn produktion då de är beroende av vädret, vilket utmanar drift och planering av elproduktion mer än tidigare samtidigt som elbehovet ökar och kommer att fortsätta öka i framtiden. Det växande elbehovet och utökningen av förnybara energikällor kräver att elnätet kan anpassas och vara flexibelt. Ett sätt att öka flexibiliteten är att värdera kapaciten i transmissionsledningar dynamiskt (DLR) istället för statiskt där kapaciteten beräknas efter värsta tänkbara scenario. Dynamisk värdering kan därför möjliggöra högre kraftöverföring i ledningarna under gynsamma väderförhållanden vilket underlättar driften och planeringen av kraftkomponenterna. I detta examensarbete studeras dynamisk värdering av transmissionsledningar i realtidselmarknaden med flera intervall (MIRTM) där driftplaneringen optimeras så att driftkostnaderna minimeras under bivillor för kraftsystemet. Målet är att undersöka hur driftkostnaderna påverkas då bivillkoret för kraftflödet i transmissionsledningarna är mer flexibelt med DLR. Resultaten från detta projekt visar att DLR kan minska kostnaderna i elnät som är överbelastade.

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