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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

Correlation of corrosion measurements and bridge conditions with NBIS deck rating

Ramniceanu, Andrei 12 November 2004 (has links)
Since the use of epoxy coated steel has become mandatory starting in the 1980s, recent studies have shown that epoxy coating does not prevent corrosion, but instead will debond from the steel reinforcement in as little as 4 years (Weyers RE et al, 1998) allowing instead a much more insidious form of corrosion to take place known as crevice corrosion. Therefore, it is important to determine if the nondestructive corrosion activity detection methods are applicable to ECR as well as institute guidelines for interpreting the results. Since the corrosion of reinforcing steel is directly responsible for damage to concrete structures, it is surprising that nondestructive corrosion assessment methods are not part of regular bridge inspection programs such as PONTIS and NBIS. Instead, the inspection and bridge rating guidelines of federally mandated programs such as NBIS are so vague as to allow for a relatively subjective application by the field inspectors. Clear cover depths, resistance, corrosion potentials, linear polarization data, as well as environmental exposure and structural data were collected from a sample of 38 bridge decks in the Commonwealth of Virginia. These structures were further divided in three subsets: bridge decks with a specified w/c ratio of 0.47, bridge decks with a specified w/c ratio of 0.45 and bridge decks with a specified w/cm ratio of 0.45. This data was then correlated to determine which parameters are the most influential in the assignment of NBIS condition rating. Relationships between the non-destructive test parameters were also examined to determine if corrosion potentials and linear polarization are applicable to epoxy coated steel. Based on comparisons of measurements distributions, there is an indication that corrosion potential tests may be applicable to structures reinforced with epoxy coated steel. Furthermore, these conclusions are supported by statistical correlations between resistivity, half cell potentials and linear polarization measurements. Unfortunately, although apparently applicable, as of now there are no guidelines to interpret the results. Based on the linear corrosion current density data collected, no conclusion can be drawn regarding the applicability of the linear polarization test. As far as the NBIS deck rating is concerned, since the inspection guidelines are so vague, age becomes a very easy and attractive factor to the field personnel to rely on. However, this conclusion is far from definitive since the very large majority of structures used in this particular study had only two rating values out of theoretically ten and realistically five possible rating values. / Master of Science
2

Facing the past : in vivo facial soft tissue depths of a modern adult population from Germany

Thiemann, Nicolle January 2016 (has links)
Forensic facial reconstruction may be the final option available to draw the public attention in cases where the identity of an individual cannot be established by standard identification methods. Two fundamental components of all forensic facial reconstruction techniques are cranial morphology and soft tissue depths databases. The purpose of this study was to extend such databases by providing a complete set of accurate facial soft tissue thickness measurements, acquired from a contemporary adult population from Germany, for use in forensic facial reconstruction. The aims were to measure the distance between well-defined landmarks on the skull and reference points on the face in a standardised manner, to analyse how sex, age and body mass index (BMI) influence facial soft tissue depths, to identify patterns of facial asymmetry, and to conduct a comparative analysis with other populations. The material for this study consisted of 320 (160 male, 160 female) anonymised multi-slice computerised tomography (MSCT) scans of individuals drawn from a German population. Individuals between the ages of 18 and 84 years were analysed. Their statures varied between 1.50 m and 1.96 m; their weights ranged between 40 kg and 145 kg. The BMI fluctuated between 16.6 kg/m2 and 45.8 kg/m2. Patients with severe trauma or pathologies that may compromise facial soft tissue depth were excluded from the study as were patients known to have been treated with specific medication (e.g. cortisone). In Amira®, 3D models of the surfaces of the skull and the facial skin were semi-automatically segmented using previously calculated thresholds and surface extraction algorithms. The parameters were adjusted to permit semi-transparent visualisation and examination of the structures of both the 3D skull and facial skin surface models simultaneously. Facial soft tissue depth was measured at 10 midline and 28 bilateral anatomical landmarks, according to the main orientations of the skull. Statistical analyses and tests were performed with SPSS® Version 22 and TDStats Version v2015.1. The analysis of facial soft tissue thickness versus BMI, sex and age, for each landmark separately, indicated that, at a number of the landmarks, facial soft tissue depth is significantly (p < 0.05) influenced by all three biometric variables. Facial soft tissue thickness increased with increasing BMI, but the correlations with age were insignificant. The differences between males and females were statistically significant (p < 0.05) for almost all anatomical landmarks with the exception of a few in the region of the nasal root and orbitals. Asymmetry was noted at over half of the bilateral landmarks. The differences between the results from this sample and those obtained from comparable databases contradict the hypothesis that population-specificity significantly influences facial soft tissue thickness. Nevertheless, this and future studies of craniofacial soft tissues will improve our knowledge of the complexity of the human face. The information gathered will be invaluable when considering forensic facial reconstruction methods for neighbouring populations.
3

Dam-break Induced Scour and Pore Water Pressure Variations Around a Vertical Structure

Rajaie, Marieh 10 December 2021 (has links)
Coastal areas in many parts of the world are vulnerable to tsunami waves. Large tsunamis are strong enough to bring about a substantial amount of sediment mobilization. Several post-tsunami field investigations performed in recent years have documented destruction induced by scouring process. For example, the 1993 Nicaraguan earthquake centred 100km off the Nicaraguan coast caused devastating tsunami-induced scour around structures and bridges (Satake et al., 1993). Differences in the scour depths were related to soil properties, shapes of structures, and tsunami hydrodynamics (Jayaratne et al., 2016). Furthermore, depending on the soil permeability, the flow and pressure propagate at different speeds within the soil, which affects water table fluctuations and the soil strength (e.g., Tonkin et al., 2003; Yeh and Li 2008). The primary objective of this research was to study the effect of different inland-propagating dam-break bore heights on pore pressure variations and scour evolution in saturated beds with two different bed slopes (i.e., zero and +5% slope) by performing comprehensive laboratory studies at a 1:40 scale. To achieve the objective, tsunami-like dam-break bores generated by rapidly opening a swing gate and propagated towards and over a sediment section and hit a structure centred within a sediment bed. The secondary objective of this experimental investigation was finding a relation between scour depths and pore pressure values as a function of still-to-impoundment water depth ratio. The results of this experimental investigation showed that effective pore pressures were consistently greater in the front face of a model than in the side face. Besides that, the highest effective pore pressures took place near the saturated bed surface. Such that, due to the propagation of supercritical bores the maximum effective pore pressure in the bottom of the front corner was 50% larger than the exact same location in the side face. While, this difference decreased to 10% in the case of subcritical bores. For the same hydrodynamic bore conditions, the maximum difference between effective pore pressure in the two faces of the model reduced by 70% in the inclined bed test than the horizontal bed tests and this difference was only 15%. However, the peak effective pore pressure around the model doubled in the inclined bed tests compared to the horizontal ones. The 5% upsloping decreased the maximum scour depths by two times as a result of the same hydrodynamic loading conditions.
4

Solution Pits

Bell, John Robert 04 1900 (has links)
Littoral solution pits were studied along 4 shorelines in the Guelph and Amabel Formations of the Bruce Peninsula. Pit depths, diameters, and densities were measured at several elevations above and below water, and various distances from the shoreline. Differences in pit characteristics were related to differences in shoreline energies, lithologies, and fluctuating lake levels in the post glacial period. Pit depths above water are shallower than pit depths below water. This conclusion supports previous hypotheses proposed by Cowell (1976) and Ford (in Goodchild, 1984) that the depth of solution pits increase with increasing water depth. The conclusions also indicate that pits are initiated above water, and that solutional deepening of pits can occur underwater. / Thesis / Bachelor of Science (BSc)
5

Burns Depth Assessment Using Deep Learning Features

Abubakar, Aliyu, Ugail, Hassan, Smith, K.M., Bukar, Ali M., Elmahmudi, Ali 20 March 2022 (has links)
Yes / Burns depth evaluation is a lifesaving task and very challenging that requires objective techniques to accomplish. While the visual assessment is the most commonly used by surgeons, its accuracy reliability ranges between 60 and 80% and subjective that lacks any standard guideline. Currently, the only standard adjunct to clinical evaluation of burn depth is Laser Doppler Imaging (LDI) which measures microcirculation within the dermal tissue, providing the burns potential healing time which correspond to the depth of the injury achieving up to 100% accuracy. However, the use of LDI is limited due to many factors including high affordability and diagnostic costs, its accuracy is affected by movement which makes it difficult to assess paediatric patients, high level of human expertise is required to operate the device, and 100% accuracy possible after 72 h. These shortfalls necessitate the need for objective and affordable technique. Method: In this study, we leverage the use of deep transfer learning technique using two pretrained models ResNet50 and VGG16 for the extraction of image patterns (ResFeat50 and VggFeat16) from a a burn dataset of 2080 RGB images which composed of healthy skin, first degree, second degree and third-degree burns evenly distributed. We then use One-versus-One Support Vector Machines (SVM) for multi-class prediction and was trained using 10-folds cross validation to achieve optimum trade-off between bias and variance. Results: The proposed approach yields maximum prediction accuracy of 95.43% using ResFeat50 and 85.67% using VggFeat16. The average recall, precision and F1-score are 95.50%, 95.50%, 95.50% and 85.75%, 86.25%, 85.75% for both ResFeat50 and VggFeat16 respectively. Conclusion: The proposed pipeline achieved a state-of-the-art prediction accuracy and interestingly indicates that decision can be made in less than a minute whether the injury requires surgical intervention such as skin grafting or not.
6

Manejo da irrigação no cultivo da cana-de-açúcar e milho sob cenários futuros: aplicação dos modelos DSSAT/CANEGRO e CERES-MAIZE / Water management for sugarcane and maize under future climate scenarios: DSSAT /CANEGRO and CERES- MAIZE models application

Oliveira, Luciano Alves de 06 February 2015 (has links)
Uma das maiores questões que a humanidade vem enfrentando nas ultimas décadas é de como suprir a demanda energética. Em meio à exploração do petróleo, várias alternativas surgiram, e uma delas é a exploração de biomassa vegetal para produção de combustíveis. Diante dessa situação, duas culturas vêm se sobressaindo nessa exploração: cana-de-açúcar e milho. Tais culturas são altamente rentáveis no que se refere à produção de carboidratos que são facilmente transformados em etanol, pela fermentação alcoólica. Portanto, a fim de aumentar seus rendimentos, a prática correta da irrigação provê a quantidade ideal de água que a planta necessita para alcançar todo o seu potencial produtivo. O manejo racional da irrigação é considerado uma prática extremamente importante nos dias atuais por estar relacionado com a economia de água, que se trata de um bem natural não renovável e que tem sua disponibilidade futura muito especulada. Juntamente a isso, em termos mais específicos, as culturas da cana-de-açúcar e do milho no estado de São Paulo têm grande importância econômica. Estas culturas vêm, a cada dia, utilizando cada vez mais a irrigação como prática comum. Diante disso, a pesquisa teve como objetivo, com olhos aos cenários futuros, tanto em função da busca por um aumento de produtividade e disponibilidade de água, avaliar lâminas de irrigação para as culturas da cana-de-açúcar e do milho, cultivadas na região de Piracicaba, SP. Para alcançar essa meta, foram aplicados os modelos DSSAT/CANEGRO e CERES-MAIZE e o modelo MarkSim, utilizado para a estimativa dos dados para cenários futuros, para alimentar os modelos de suporte à decisão. Para tal, Foram utilizadas informações do relatório do IPCC (Intergovernmental Panel of Climate Changes) tanto para o cenário atual, quanto para os cenários futuros definidos como: A1B, A2 e B1. Foi utilizada uma série de 31 anos de dados climáticos (Temperatura Máxima e Mínima, Radiação Solar e Chuva), período de 1982 a 2012, para a região de Piracicaba, SP, obtida pela Estação Meteorológica pertence ao Departamento de Engenharia de Biossistemas da ESALQ/USP. Uma série também de 31 anos, representou os dados climáticos, de cenários futuros, simulados pelo modelo MarkSim e corresponderam ao período de 2062 a 2092, para a região de Piracicaba,SP. As análises estatísticas das lâminas de irrigação foram comparadas pelo método de Tukey ao nível de 5% de probabilidade. Diante dos resultados obtidos, para os cenários futuros, a cana-de-açúcar terá uma redução de produtividade da ordem de 40% em relação ao cenário atual e não será o suprimento hídrico que conseguirá evitar tal redução. As lâminas de irrigação nos cenários futuros também apresentaram reduções da ordem de 40%. Em relação à cultura do milho, para se manter os mesmos níveis de produtividade, será necessário um incremento de 81% nas lâminas de irrigação, diante dos cenários futuros. Conclui-se que diante de cenários futuros, a cana-de-açúcar, para a manutenção de sua produtividade, sugere-se um envolvimento com outros campos de pesquisa, dentre eles a área de genética, buscando desenvolver novas variedades tolerantes a essas variações climáticas e no caso do cultivo do milho o manejo racional da água em dias atuais, passa a ser fundamental. / Over the last several decades, there have been concerns worldwide about coping with increasing energy demand. Several alternatives to oil have emerged, among them the use of plant biomass for fuel. Sugarcane and maize have exhibited excellent potential in this regard. These crops are highly efficient in producing carbohydrates which can easily be fermented to produce ethanol. Proper irrigation practices, providing the ideal amount of water that the plant needs to reach its full potential yield, are needed to maximize income from these crops. Rational irrigation management is considered an important practice because it promotes sustainable water use. Sugarcane and maize are of great economic importance to the state of São Paulo, where it is common to irrigate these crops. This research aims to determine conditions for increased productivity and water availability for these crops in the region of Piracicaba, SP, under future climate scenarios. To achieve this goal, the DSSAT/CANEGRO and CERES-MAIZE crop growth models were coupled with the MarkSim model for estimating data for future climate scenarios. Information from the Intergovernmental Panel on Climate Change (IPCC) was used to generate data for current conditions, as well as for the A1B, A2 and B1 future scenarios. Current climate data (Minimum Temperature and Solar Radiation and Rain) for the period 1982 to 2012 for Piracicaba, SP, were obtained by meteorological station operated by the Department of Biosystems Engineering at ESALQ / USP. MarkSim was used to generate data for the same region for 2062 to 2092. The Tukey method, at a 5% level of significance was used to compare irrigation levels for current and future scenarios. Based on these results, for future scenarios, sugar cane productivity will be reduced by approximately 40%, and there will not be enough water to mitigate such an effect. The water depth in future scenarios was also reduced by approximately 40%. To maintain the same levels of productivity in corn, will be necessary to increase irrigation water by 81%. In conclusion, it is recommended that research be conducted in other areas if sugarcane productivity is to be maintained. Examples include genetic research to develop new varieties tolerant to climate variations. For maize cultivation, it is crucial the rational water management be introduced as soon as possible.
7

Consumo e custo de energia elétrica na cultura de citros irrigada por gotejamento e microaspersão, com três lâminas de água

Vescove, Humberto Vinicius [UNESP] 06 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-06Bitstream added on 2014-06-13T18:41:29Z : No. of bitstreams: 1 vescove_hv_dr_jabo.pdf: 630243 bytes, checksum: b66c2dbcbb17475abf180fe7521ce34a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi analisar o consumo, o custo de energia elétrica e resultado econômico em citros (Citrus sinensis) irrigado. Os tratamentos constaram de sistemas de irrigação do tipo gotejamento, com uma e duas linhas laterais de distribuição de água, microaspersão e um tratamento sem irrigação. Para cada sistema foram utilizadas três lâminas de água; 100%, 75% e 50% da Etc (evapotranspiração da cultura). Foi estudado o custo da energia elétrica para dois grupos tarifários, Grupo A e Grupo B. No grupo A foram determinados os dispêndios com a energia para tarifas Estrutura Binômia Convencional e Horo-Sazonal (verde e azul), além, da tarifa especial para irrigante noturno. Os preços de demanda e kWh dos sistemas tarifários foram obtidos no site CPFL (Companhia Paulista de Força e Luz). A menor relação entre o consumo de energia elétrica por ha (kWh.ha-1) e a produtividade (t) foi obtida nos tratamentos irrigados com 50% da Etc. O sistema tarifário horosazonal verde/azul Grupo A irrigante noturno teve o menor custo de energia. Os tratamentos irrigados com lâmina de 50% apresentaram maiores produtividade em relação à lâmina de 100% da Etc. O maior retorno econômico ocorreu nos tratamentos irrigados com 50% da Etc. / The objective of this work is to analyze the consumption, the electric energy cost, and the economic results in irrigated citros (Citrus sinensis). The procedures used consisted of a dripping equipment, with one and two lateral lines of water distribution, a micro sprinkler as well as a treatment without irrigation. For each system of irrigation, three water depths have been used; 100%, 75% and 50% of Etc (citrus evapotranspiration). The electric energy cost was studied for two tariff groups, Group A and Group B. For the Group A it was determined the expenses with the energy for the tariffs Binômia Structure Convencional and Horo-Sazonal (green and blue), besides the special tariff for nocturnal irrigation. The prices of the kWh tariff were obtained from the CPFL site ( power company of Sao Paulo, Brazil). The best relation between the consumption of electric energy (kWh.ha-1) and the productivity (t.ha-1) occurred when the irrigation is done with 50% of the Etc. The tariff system Horo-Sazonal green and blue of the Group A, with nocturnal irrigation, showed the smaller energy cost. The irrigated treatments with depth of 50% have presented higher productivity than those of 100% of Etc. Higher economical returns are achieved when the treatments irrigated with 50% of the Etc are chosen.
8

Consumo e custo de energia elétrica na cultura de citros irrigada por gotejamento e microaspersão, com três lâminas de água /

Vescove, Humberto Vinicius. January 2009 (has links)
Orientador: José Eduardo Pitelli Turco / Banca: Luiz Antonio Rossi / Banca: Odivaldo José Seraphim / Banca: José Carlos Barbosa / Banca: João Antonio Galbiatti / Resumo: O objetivo deste trabalho foi analisar o consumo, o custo de energia elétrica e resultado econômico em citros (Citrus sinensis) irrigado. Os tratamentos constaram de sistemas de irrigação do tipo gotejamento, com uma e duas linhas laterais de distribuição de água, microaspersão e um tratamento sem irrigação. Para cada sistema foram utilizadas três lâminas de água; 100%, 75% e 50% da Etc (evapotranspiração da cultura). Foi estudado o custo da energia elétrica para dois grupos tarifários, Grupo A e Grupo B. No grupo A foram determinados os dispêndios com a energia para tarifas Estrutura Binômia Convencional e Horo-Sazonal (verde e azul), além, da tarifa especial para irrigante noturno. Os preços de demanda e kWh dos sistemas tarifários foram obtidos no site CPFL (Companhia Paulista de Força e Luz). A menor relação entre o consumo de energia elétrica por ha (kWh.ha-1) e a produtividade (t) foi obtida nos tratamentos irrigados com 50% da Etc. O sistema tarifário horosazonal verde/azul Grupo A irrigante noturno teve o menor custo de energia. Os tratamentos irrigados com lâmina de 50% apresentaram maiores produtividade em relação à lâmina de 100% da Etc. O maior retorno econômico ocorreu nos tratamentos irrigados com 50% da Etc. / Abstract: The objective of this work is to analyze the consumption, the electric energy cost, and the economic results in irrigated citros (Citrus sinensis). The procedures used consisted of a dripping equipment, with one and two lateral lines of water distribution, a micro sprinkler as well as a treatment without irrigation. For each system of irrigation, three water depths have been used; 100%, 75% and 50% of Etc (citrus evapotranspiration). The electric energy cost was studied for two tariff groups, Group A and Group B. For the Group A it was determined the expenses with the energy for the tariffs Binômia Structure Convencional and Horo-Sazonal (green and blue), besides the special tariff for nocturnal irrigation. The prices of the kWh tariff were obtained from the CPFL site ( power company of Sao Paulo, Brazil). The best relation between the consumption of electric energy (kWh.ha-1) and the productivity (t.ha-1) occurred when the irrigation is done with 50% of the Etc. The tariff system Horo-Sazonal green and blue of the Group A, with nocturnal irrigation, showed the smaller energy cost. The irrigated treatments with depth of 50% have presented higher productivity than those of 100% of Etc. Higher economical returns are achieved when the treatments irrigated with 50% of the Etc are chosen. / Doutor
9

The Study of Quenching of the Excited States of Nitric Oxide in the Presence of Foreign Gas

Wang, Chu-Tung 11 July 2002 (has links)
In the fluorescence excitation spectra, fluorescence cross sections can be measured by the normalization of absorption cross section of A(0) or D(0) states. In the presence of foreign gases, the self-quenching rate constants, the half-quenching pressures and the quenching rate constants of D(0) and D(1) states are measured and the results are compared with the previous works. In the additional of foreign gases, the enhancement of global fluorescence of the strong predissociation states of C(1) and B(9) is due to the collision-induced transition. In the case of N2, the enhancement of fluorescence of £^band is owing to the resonance transfer. Finally, the well depth of the van der Walls molecules which are formed by the excited state of NO with quenching gas can be derived from the measured quenching cross sections.
10

MAPPING SOIL PROPERTIES AND WATER TABLE DEPTHS USING ELECTROMAGNETIC INDUCTION METHODS

Khan, Fahad 15 March 2012 (has links)
Detailed soil and water data are essential to ensure the optimum long-term management of fields. The objective of this study was to estimate water table depths, spatially variable and layered soil properties using electromagnetic induction methods. Soil samples were collected and analyzed within two wild blueberry, a soybean-barley and a pasture fields. Observation wells were installed. The DualEM-2 was calibrated to predict the soil properties and groundwater depths. The apparent ground conductivity (ECa) and water table depths were measured simultaneously from each well, before and after every significant rainfall for three consecutive days. Comprehensive surveys were conducted in selected fields to measure ECa with DualEM-2. Survey data were imported in C++ program to estimate layered soil properties using mathematical models. Regression models were developed to predict soil properties and groundwater depths. The predicted soil properties and groundwater table maps were generated. This information can help to develop variable rate technologies.

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