published_or_final_version / Civil and Structural Engineering / Master / Master of Philosophy

Doctor of Philosophy / Department of Civil Engineering / Sunanda Dissanayake / Setting an appropriate speed limit is necessary to provide safe and efficient traffic operation for all road users. It must also be acceptable to the public and enforceable by police. Lower-than-required speed limits may make the majority of drivers non-compliant, whereas higher speed limits may increase the number of crashes together with related injuries and fatalities. In 2011, the speed limit on a number of freeway segments in the state of Kansas increased from 70 to 75 miles per hour. The objective of this study is to evaluate the safety effects of freeway sections affected by speed limit change in Kansas. Sections where the speed limit changed from 70 mph to 75 mph and other comparable sections where the speed limit remained at 70 mph without any change, were identified. Details of the crashes by severity level for three years before (2008-2010) and three years after (2012-2014) the speed limit change were collected using the state crash database. In order to get a general understanding, characteristics of crashes such as night time versus daytime, number of trucks involved, weather conditions, driver’s gender, and such were considered. Furthermore, several crash contributory causes were also investigated before and after the speed limit changes. In order to evaluate the safety situation, three methods were utilized: 1) Empirical Bayes (EB) observational before-and-after studies, 2) before-and-after method with comparison group, and 3) cross-sectional method using the Negative Binomial (NB) regression model. The evaluation was conducted to see if the speed limit change has caused an increase in total crashes or fatal and injury crashes. In regard to speed analysis, the t-test was applied to see whether significant increases in the 85th percentile speed were observed between before-and-after conditions. Since the sample size was large, the Kolmogorov-Smirnov (K-S) test was also conducted to see if there was any difference between two sets of speed data distributions in the before period compared to the after period. By performing the EB before-and-after study, it was seen that total crashes increased by 16 percent, while using the before-and-after method with the comparison group showed around 27 percent increase in total crashes. Total crash increases were statistically significant according to the EB method, and the before-and-after method with the comparison group. On the other hand, fatal and injury crashes increased by 35 percent based on the before-and-after with the comparison group after the speed limit change. This increase was statistically significant, but the EB method results indicated no increase for fatal and injury crashes when the speed limit was raised to 75 mph. Further, cross-sectional study results showed the speed limit increase had a greatly significant effect on total crashes, an increase of 25 percent; and it was also significant for fatal and injury crashes with those increasing by 62 percent, which is the highest amount of increase compared to the EB method and the before-and-after method with the comparison group. The t-test results showed a five mph increase in the speed limit caused statistically significant increase in 85th percentile speed for the sections affected by speed limit change. However, there was also an increase for the sections without a speed limit change, but this was due to large sample sizes of speed data in the before-and-after period. The K-S test results also depicted the speed distribution of treated sites during the after period was different than the before period. Considering night time crashes versus daytime crashes also showed that there was 1 percent statistically significant increase in the night time crashes compared to daytime crashes after the speed limit increase. There were also more trucks involved in crashes after the speed limit increase. Further, the percentage of adverse weather crashes also decreased by 6 percent for treated sites and 18 percent for non-treated sites. Overall, understanding these results will help with future speed limit adjustments on freeways.

The Commercial Vehicle Safety Alliance (CVSA) is an association of industry representatives, and state, territorial, provincial, and federal government officials in the United States, Canada, and Mexico. The CVSA's goal is to improve commercial vehicle safety. The CVSA concentrates its safety focus on three areas; driver, vehicle, and hazardous materials. Since 1981, the CVSA has developed a set of criteria for each of the three areas that define conditions which are so unsafe that a truck and/or driver should not be allowed to operate. These criteria are known as out of service (OOS) criteria. To check the compliance of motor carriers with the CVSA criteria, a series of road side inspections is conducted by state and local governments. If the driver and/or vehicle are found in violation of the CVSA OOS criteria, they are placed "out of service" until the conditions are completely remedied. Due to criteria growth, the CVSA wanted to examine the OOS criteria in the vehicle and hazardous materials areas. This study, focused on the vehicle portion of the OOS criteria, attempted to correlate commercial vehicle defects to commercial vehicle accidents. For a major portion of this project, actual accident reports from six states of the United States were evaluated. The states and reports were selected via a stratified two stage cluster sampling system. The results were used to form estimates of the proportion and number of commercial vehicle accidents in the United States with a mechanical defect as a contributing factor. In addition to the accident report sampling, other sources were used to establish a correlation between vehicle defects and commercial vehicle accidents. They include literature, national databases, and post-crash inspections. Results from this study show that approximately 4.6% of all commercial vehicle accidents have a mechanical defect as a factor contributing to the accident. Of these, brakes (1.66%), tires (0.45%), couplings (0.38%), load securement (0.37%), and wheels (0.33%) accounted for the majority. A comparison was also made between the OSU study results and the information gathered from other sources. A cost factor was also used to rank the accidents. The sampled accidents accrued $22.7 million in damage to people and property. The underlying assumption is vehicle defects that are strongly represented in accidents and accident damage estimates should have a strong representation in the out-of-service criteria. / Graduation date: 1997

Baihetan Dam is sited on the lower reaches of the Jinsha River in the southwest of China between the boarders of Sichuan and Yunnan province. The dam is scheduled to be taken into operation in the year of 2020 with an installed generation capacity of 14 GW which will put Baihetan Dam on the map as the third largest hydropower station in the world considering installed power output. In comparison, the world’s biggest dam Three Gorges has an installed generation capacity of 22,5 GW. To ensure a sufficient safety evaluation in terms of erosion (scour) formation at the bottom of the plunge pool, pressure simulations in the plunge pool floor in an experimental model at the Department of Hydraulic Engineering in Tsinghua University, Beijing, China has been performed. Data from two experiments with two different outflow configurations has been obtained and analyzed together with three earlier performed experiments on the same experimental model. The results from outflow configuration one had an incomplete data set and could not be compared to the other experiments. The results retrieved from the other experiments however showed the importance of a spillway design with nappe splitters and nappe blocks implemented and the value of a sufficient water cushion in the plunge pool. All four outflow configurations with nappe splitters or nappe blocks implemented held a hydrodynamic pressure below the recommended maximum pressure value of 15 cm water head (experimental model scale) stated by the East Asian Investigation and Design Institute, whilst the one configuration with no nappe splitters or nappe blocks exceeded the value. The design of outflow configuration two is four nappe splitters implemented in two spillways and two nappe blocks in two spillways. In this thesis, this configuration has proven to be the most suitable one in terms of maximum pressure minimization and pressure distribution at the plunge pool floor.

As fontes radioativas seladas em desuso, descartadas como rejeito radioativo, constituem uma parcela dos rejeitos radioativos que merece atenção especial, por sua atividade possuir potencial para causar doses de radiação elevadas, em indivíduos inadvertidamente expostos. Já é significativo o volume desses rejeitos. Manter essas fontes armazenadas em depósitos provisórios, indefinidamente, seria transferir o problema às futuras gerações. O presente estudo propõe o uso de indicadores de segurança complementares à dose e risco para o desenvolvimento de uma metodologia de avaliação da segurança de depósitos finais destinados à deposição de fontes radioativas seladas que demonstre que o isolamento será suficientemente seguro pelo tempo necessário para obter a licença da instalação, com custo acessível aos países em desenvolvimento. / Disused sealed radioactive sources are a kind of radioactive waste that deserves especial attention because the radioactivity present in a relevant fraction of the number of sources is high enough to cause severe effects in accidentally exposed individuals. The present inventory of disused sources is of the order of tens of thousands. Keep these sources indefinitely under interim storage is bequeath the problem of final disposal to the future generations. The present study proposes the use of Safety Indicators as a contribution to the development of methodologies for the assessment of safety in a deep borehole repository for sealed sources. These methodologies are required to demonstrate the long-term safety at a cost affordable to developing countries.

As fontes radioativas seladas em desuso, descartadas como rejeito radioativo, constituem uma parcela dos rejeitos radioativos que merece atenção especial, por sua atividade possuir potencial para causar doses de radiação elevadas, em indivíduos inadvertidamente expostos. Já é significativo o volume desses rejeitos. Manter essas fontes armazenadas em depósitos provisórios, indefinidamente, seria transferir o problema às futuras gerações. O presente estudo propõe o uso de indicadores de segurança complementares à dose e risco para o desenvolvimento de uma metodologia de avaliação da segurança de depósitos finais destinados à deposição de fontes radioativas seladas que demonstre que o isolamento será suficientemente seguro pelo tempo necessário para obter a licença da instalação, com custo acessível aos países em desenvolvimento. / Disused sealed radioactive sources are a kind of radioactive waste that deserves especial attention because the radioactivity present in a relevant fraction of the number of sources is high enough to cause severe effects in accidentally exposed individuals. The present inventory of disused sources is of the order of tens of thousands. Keep these sources indefinitely under interim storage is bequeath the problem of final disposal to the future generations. The present study proposes the use of Safety Indicators as a contribution to the development of methodologies for the assessment of safety in a deep borehole repository for sealed sources. These methodologies are required to demonstrate the long-term safety at a cost affordable to developing countries.

In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions in the field and a few years must pass before accumulating reliable crash data. This is a time-consuming approach and there remains uncertainty in the crash data due to the random nature of crash occurrences. The Surrogate Safety Assessment Model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative under study is modeled and no physical installation of the alternative is needed. Hence, the method using a simulation software along with SSAM consumes less time compared to other traditional safety analysis methods that may require a physical installation of the new alternative and a long wait time for data collection. The purpose of this study is to evaluate if SSAM can be used to assess the safety of a highway segment or an intersection in term of the number and type of conflicts and to compare the safety effects of multiple access management alternatives with less time, less cost and less uncertainty than the traditional safety analysis methods. To meet the purpose of the study, two study sections, one on University Parkway in Orem and Provo and the other on Main Street in American Fork were selected and analyzed in this research. Based on the findings from the calibration of SSAM on the University Parkway study section, an evaluation of the effect of converting a TWLTL median into a raised median on a section of Main Street (US-89) from 300 West to 500 East in American Fork was performed using SSAM working on VISSIM simulation's trajectory files of the study section. This evaluation study was conducted to show how SSAM could be used to evaluate the effect of access management alternatives using surrogate safety measures. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume. Approximately a 32 to 50 percent reduction in the number of crossing conflicts was achieved when a raised median was used in lieu of a TWLTL median at the Main Street study section.

Made available in DSpace on 2014-06-11T19:32:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-03Bitstream added on 2014-06-13T18:43:04Z : No. of bitstreams: 1 chorilli_m_dr_arafcf.pdf: 6828214 bytes, checksum: e7f3732e2e09e7a3c509d1c9cc6b1d5e (MD5) / Universidade Estadual Paulista (UNESP) / O estudo de sistemas nanoestruturados tem chamado a atenção de um número cada vez maior de pesquisadores das áreas farmacêutica e cosmética, devido às inúmeras vantagens conferidas, como aumento da estabilidade e eficácia de princípios ativos. Os efeitos desses sistemas na pele são dificilmente relatados na literatura científica. Os objetivos deste trabalho foram: desenvolver e caracterizar fisico-quimicamente sistemas nanoestruturados contendo palmitato de retinol (PR); realizar os testes de estabilidade preliminares (TEP) para as formulações selecionadas; realizar o controle microbiológico bem como o teste de desafio para eficácia conservante para as formulações empregadas; verificar o efeito irritativo das formulações segundo escala de Draize e por análise histológica, além de avaliar a eficácia das formulações no tratamento do envelhecimento cutâneo. As formulações preparadas com silicone fluido de co-polímero glicol (SFCG), poliéter funcional siloxano (PFS) e água (S1) e com adipato de diisopropila, PFS e água (S4) apresentaram fases líquido-cristalinas do tipo lamelar. Os TEPs evidenciaram que as formulações F1, F2 e F3 de todos os sistemas desenvolvidos se mantiveram estáveis durante o período do estudo. As formulações do sistema S1 apresentaram maior formação e estabilidade de cristais líquidos no decorrer do experimento, sendo selecionadas para incorporação de PR. As formulações F1, F1v, F4 e F4v do sistema S1 e a formulação F5 do sistema S4 apresentaram-se como fluidos pseudoplásticos não–Newtonianos. A formulação F5 foi a mais tixotrópica, seguido pelas formulações F1v e F1. As condições de armazenamento, de acordo com os ensaios de escoamento e mecânicodinâmicos, interferem na estruturação do sistema. As formulações F1, F1v, F4 e F4v não apresentaram contaminação microbiana... / The study of nanostructured systems has interested an inreasing number of pharmaceutical and cosmetic areas researchers, due to the great advantage, as increase of the stability and effectiveness of active substances. The effects of those systems in the skin poorly reported on the scientific literature. The aims of this work were: to develop and to characterize physicochemically nanostructured systems containing retynil palmitate (RP); to carry out a preliminary stability tests (PST) for the selected formulations; to carry through the microbiological control as well the challenge test for preservative effectiveness for the used formulations; to evaluate the irritation effect of the formulations according to Draize scale and histological analysis, besides to evaluate the effectiveness of the formulations in the treatment of the cutaneous aging. The formulations prepared with silicon glycol copolymer (SGC), polyether functional siloxane (PFS) and water (S1) and with diisopropyl adipate, PFS and water (S4) presented liquid-crystalline phases with lamellar arrangement. The PST evidenced that the formulations F1, F2 and F3 of all the developed systems remained stable throughout the period of study. The formulations of the S1 system presented higher formation of liquid crystals and better stability, being selected for incorporation of RP. The formulations F1, F1v, F4 and F4v of the S1 system and the formulation F5 of the S4 system presented as not- Newtonian pseudoplastic fluids. The formulation F5 was the most thixotropic, followed by the formulations F1v and F1. The storage conditions, in accordance with draining and mechanicdynamic assays, interfere with the structure of the system. The formulations F1, F1v, F4 and F4v did not present microbiological contamination, evidenced by the estimate of the number of viable microorganisms and by the presence... (Complete abstract click electronic access below)

Resumo: O estudo de sistemas nanoestruturados tem chamado a atenção de um número cada vez maior de pesquisadores das áreas farmacêutica e cosmética, devido às inúmeras vantagens conferidas, como aumento da estabilidade e eficácia de princípios ativos. Os efeitos desses sistemas na pele são dificilmente relatados na literatura científica. Os objetivos deste trabalho foram: desenvolver e caracterizar fisico-quimicamente sistemas nanoestruturados contendo palmitato de retinol (PR); realizar os testes de estabilidade preliminares (TEP) para as formulações selecionadas; realizar o controle microbiológico bem como o teste de desafio para eficácia conservante para as formulações empregadas; verificar o efeito irritativo das formulações segundo escala de Draize e por análise histológica, além de avaliar a eficácia das formulações no tratamento do envelhecimento cutâneo. As formulações preparadas com silicone fluido de co-polímero glicol (SFCG), poliéter funcional siloxano (PFS) e água (S1) e com adipato de diisopropila, PFS e água (S4) apresentaram fases líquido-cristalinas do tipo lamelar. Os TEPs evidenciaram que as formulações F1, F2 e F3 de todos os sistemas desenvolvidos se mantiveram estáveis durante o período do estudo. As formulações do sistema S1 apresentaram maior formação e estabilidade de cristais líquidos no decorrer do experimento, sendo selecionadas para incorporação de PR. As formulações F1, F1v, F4 e F4v do sistema S1 e a formulação F5 do sistema S4 apresentaram-se como fluidos pseudoplásticos não-Newtonianos. A formulação F5 foi a mais tixotrópica, seguido pelas formulações F1v e F1. As condições de armazenamento, de acordo com os ensaios de escoamento e mecânicodinâmicos, interferem na estruturação do sistema. As formulações F1, F1v, F4 e F4v não apresentaram contaminação microbiana... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study of nanostructured systems has interested an inreasing number of pharmaceutical and cosmetic areas researchers, due to the great advantage, as increase of the stability and effectiveness of active substances. The effects of those systems in the skin poorly reported on the scientific literature. The aims of this work were: to develop and to characterize physicochemically nanostructured systems containing retynil palmitate (RP); to carry out a preliminary stability tests (PST) for the selected formulations; to carry through the microbiological control as well the challenge test for preservative effectiveness for the used formulations; to evaluate the irritation effect of the formulations according to Draize scale and histological analysis, besides to evaluate the effectiveness of the formulations in the treatment of the cutaneous aging. The formulations prepared with silicon glycol copolymer (SGC), polyether functional siloxane (PFS) and water (S1) and with diisopropyl adipate, PFS and water (S4) presented liquid-crystalline phases with lamellar arrangement. The PST evidenced that the formulations F1, F2 and F3 of all the developed systems remained stable throughout the period of study. The formulations of the S1 system presented higher formation of liquid crystals and better stability, being selected for incorporation of RP. The formulations F1, F1v, F4 and F4v of the S1 system and the formulation F5 of the S4 system presented as not- Newtonian pseudoplastic fluids. The formulation F5 was the most thixotropic, followed by the formulations F1v and F1. The storage conditions, in accordance with draining and mechanicdynamic assays, interfere with the structure of the system. The formulations F1, F1v, F4 and F4v did not present microbiological contamination, evidenced by the estimate of the number of viable microorganisms and by the presence... (Complete abstract click electronic access below) / Orientador: Maria Virgínia Scarpa / Coorientador: Gislaine Ricci Leonardi / Banca: Stanisçuaski Guterres / Banca: Hérida Regina Nunes Salgado / Banca: Telma Mary Kaneko / Banca: Leila Aparecida Chiavacci / Doutor

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