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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

Field evaluation and analysis of automated rut measurement systems data for Texas conditions

Serigos, Pedro Antonio 09 July 2012 (has links)
This study evaluated the performance of state-of-the-practice automated rut measurement systems (ARMS) for measuring rutting in the field at highway speeds under Texas conditions. A total of twenty-four 550-ft survey sections were selected with the objective of establishing representative conditions encountered on Texas highways as well as cases considered potentially problematic for automated rutting surveys. Five different ARMS measured the twenty-four sections at highways speeds and reported their best estimates of the transverse profiles coordinates at 552 stations and the Maximum Rut Depth (MRD) values for each wheel-path at 2,664 stations. These measurements were compared with the manual measurements taken statically at the same locations. The reference transverse profiles were manually measured using a laser distance meter and a leveled beam and the reference MRD values were manually measured using a 6ft straight-edge and a gage graduated to 16ths of an inch. In addition, the effect of different experimental variables on each system’s measurement errors was analyzed aiming to detect which pavement characteristics are more challenging for the ARMS. / text
2

Field Evaluation Methodology for Quantifying Network-wide Efficiency, Energy, Emission, and Safety Impacts of Operational-level Transportation Projects

Sin, Heung Gweon 28 September 2001 (has links)
This thesis presents a proposed methodology for the field evaluation of the efficiency, energy, environmental, and safety impacts of traffic-flow improvement projects. The methodology utilizes Global Positioning System (GPS) second-by-second speed measurements using fairly inexpensive GPS units to quantify the impacts of traffic-flow improvement projects on the efficiency, energy, and safety of a transportation network. It should be noted that the proposed methodology is incapable of isolating the effects of induced demand and is not suitable for estimating long-term impacts of such projects that involve changes in land-use. Instead, the proposed methodology can quantify changes in traffic behavior and changes in travel demand. This thesis, also, investigates the ability of various data smoothing techniques to remove such erroneous data without significantly altering the underlying vehicle speed profile. Several smoothing techniques are then applied to the acceleration profile, including data trimming, Simple Exponential smoothing, Double Exponential smoothing, Epanechnikov Kernel smoothing, Robust Kernel smoothing, and Robust Simple Exponential Smoothing. The results of the analysis indicate that the application of Robust smoothing (Kernel of Exponential) to vehicle acceleration levels, combined with a technique to minimize the difference between the integral of the raw and smoothed acceleration profiles, removes invalid GPS data without significantly altering the underlying measured speed profile The methodology has been successfully applied to two case studies provided insights as to the potential benefits of coordinating traffic signals across jurisdictional boundaries. More importantly two case studies demonstrate the feasibility of using GPS second-by-second speed measurements for the evaluation of operational-level traffic flow improvement projects. To identify any statistically significant differences in traffic demand along two case study corridors before and after traffic signal condition, tube counts and turning counts were collected and analyzed using ANOVA technique. The ANOVA results of turning volume counts indicated that there is no statistically significant difference in turning volumes between the before and after conditions. Furthermore, the ANOVA results of tube counts also confirmed that there did not appear to be a statistically significant difference (5 percent level of significance) in the tube counts between the before and after conditions. / Ph. D.
3

Evaluation of Multiple Insecticidal Products for Control of the Common Bed Bug (Cimex lectularius (L.))

Moore, David Joseph II 12 January 2007 (has links)
The common bed bug has reemerged as a major pest in the United States. Pest management professionals need reliable up-to-date information on how to manage bed bug infestations. My study was intended to evaluate the efficacy of several insecticides currently labeled for bed bug control. In product efficacy tests, field strain bed bugs were found to be 99-450 times less susceptible than laboratory strain bed bugs to several pyrethroid products. The non-pyrethroid products tested, chlorfenapyr and a non-toxic desiccant dust, killed laboratory strain bed bugs, but were extremely slow acting taking greater than 9 days to kill 50%. None of the insecticides tested, including the pyrethroids, were repellent to laboratory or field strain bed bugs. A field test was conducted comparing 2 pesticide treatments regimens (traditional and novel) for bed bug control in low income apartments. Both the traditional and novel combinations caused significant reductions in bed bug populations. Both treatments reduced the number of bed bugs by the end of the test period, but neither treatment combination completely eliminated the bed bug infestations, even after an average of 1.3 gallons of product was applied in each apartment. Laboratory assays were conducted to determine the effect of hydroprene exposure on bed bug development. Although hydroprene did not appear to interfere with nymphal development, fifty percent of the bed bugs died during the final molt. The bed bugs which survived to adulthood showed no reduction in fecundity when compared to control groups. / Master of Science in Life Sciences
4

Molecular characterisation and expression profiles of the CP4 EPSPS gene in field-tested transgenic onions (Allium cepa L.)

Davis, Sheree Alma January 2007 (has links)
The onion (Allium cepa L.) is the most agronomically important vegetable crop to New Zealand. In temperate climates, such as New Zealand, the most prominent problem associated with onion production is weed control. To address this problem, glyphosate-resistant onions were generated in a range of germplasm backgrounds via Agrobacterium-mediated transformation of immature embryos (Eady et al. 2003a). This thesis contains an analysis of these onions. PCR and Southern analysis were used to create molecular profiles for individual transgenic events. Of the 17 putatively transgenic onion lines tested, 16 contained a single copy of the CP4 EPSPS gene integrated into their genomes, and one line had two copies of the gene. The spectinomycin resistance gene, located on the backbone of the vectors used in the transformation process, was detected in two of the glyphosate-resistant onion lines tested. Ten different glyphosate-resistant onion lines were subjected to field trial evaluation over the 2004/2005 growing season in Canterbury. Glyphosate-resistant onion seedlings were transplanted into the field in a randomised block design and a subset of plants, chosen to represent selected lines, were sampled. Tissue was harvested from young leaves, old leaves, and bulbs. Quantitative multiplex RT-PCR was used to assess expression of the CP4 EPSPS transcript, and protein levels were determined using an ELISA-based assay. The transgene appears to be highly transcribed in some lines, as expression of the CP4 EPSPS gene was in the same order of magnitude as the highly transcribed 18S internal control. The CP4 EPSPS protein levels of the glyphosate resistant onion lines presented in this thesis ranged between 0.36–7.44 µg CP4 g-1FW in the leaf samples, which is a little lower than, but still similar to, values reported for glyphosate resistant corn and poplar. This project reports the first in-depth analysis into the expression of the CP4 EPSPS gene in field-grown glyphosate-resistant onion lines.
5

Molecular characterisation and expression profiles of the CP4 EPSPS gene in field-tested transgenic onions (Allium cepa L.)

Davis, Sheree Alma January 2007 (has links)
The onion (Allium cepa L.) is the most agronomically important vegetable crop to New Zealand. In temperate climates, such as New Zealand, the most prominent problem associated with onion production is weed control. To address this problem, glyphosate-resistant onions were generated in a range of germplasm backgrounds via Agrobacterium-mediated transformation of immature embryos (Eady et al. 2003a). This thesis contains an analysis of these onions. PCR and Southern analysis were used to create molecular profiles for individual transgenic events. Of the 17 putatively transgenic onion lines tested, 16 contained a single copy of the CP4 EPSPS gene integrated into their genomes, and one line had two copies of the gene. The spectinomycin resistance gene, located on the backbone of the vectors used in the transformation process, was detected in two of the glyphosate-resistant onion lines tested. Ten different glyphosate-resistant onion lines were subjected to field trial evaluation over the 2004/2005 growing season in Canterbury. Glyphosate-resistant onion seedlings were transplanted into the field in a randomised block design and a subset of plants, chosen to represent selected lines, were sampled. Tissue was harvested from young leaves, old leaves, and bulbs. Quantitative multiplex RT-PCR was used to assess expression of the CP4 EPSPS transcript, and protein levels were determined using an ELISA-based assay. The transgene appears to be highly transcribed in some lines, as expression of the CP4 EPSPS gene was in the same order of magnitude as the highly transcribed 18S internal control. The CP4 EPSPS protein levels of the glyphosate resistant onion lines presented in this thesis ranged between 0.36–7.44 µg CP4 g-1FW in the leaf samples, which is a little lower than, but still similar to, values reported for glyphosate resistant corn and poplar. This project reports the first in-depth analysis into the expression of the CP4 EPSPS gene in field-grown glyphosate-resistant onion lines.
6

Pre-release Evaluation of Laricobius osakensis Montgomery and Shiyake (Coleoptera: Derodontidae), a Potential Biological Control Agent for the Hemlock Woolly Adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the Eastern United States

Marques Cota Vieira, Ligia Maria 03 May 2013 (has links)
Hemlock woolly adelgid, Adelges tsugae Annand, is an invasive pest threatening eastern (Tsuga canadensis (L.) Carrière) and Carolina hemlock (T. caroliniana Englem.) forests in the eastern US. A new predator, Laricobius osakensis Montgomery and Shiyake, has been found in association with A. tsugae in Japan. Laricobius osakensis was evaluated in a series of pre-release studies to assess its potential as a biological control agent for A. tsugae. Host-range studies indicated that L. osakensis is a specific predator that feeds predominantly and reproduces only on A. tsugae. The functional response "prey consumption changes in response to changes in prey density" was similar for both L. osakensis and Laricobius nigrinus Fender adults. However, L. osakensis had a higher numerical response"changes in oviposition in response to changes in prey density"than L. nigrinus. Laricobius osakensis larvae had a higher functional response than L. nigrinus larvae. Laricobius osakensis\' higher numerical and functional response indicates that this species can potentially be more effective than L. nigrinus. In the evaluation of L. osakensis in sleeve cages in the field from December to April high rates of adult survival, feeding, and reproduction were found. A pair of predators in a cage killed on average five adelgids/day. Peak oviposition occurred in March and April. Larvae from eggs placed in the cages reached maturity in 28-50 days, depending on the season, and only 6.7 % died before reaching maturity. Laricobius osakensis was able to survive, feed, develop, and reproduce in USDA cold-hardiness zones 5b and 6a of southwest Virginia. Behavior of L. osakensis and L. nigrinus was qualitatively similar but varied quantitatively. Laricobius osakensis was more active and had a lower association with T. canadensis. Interactions between species were minimal and not detrimental to either. Intrasexual copulation attempts were observed between males and to a lesser extent between females; however, intrasexual interactions were less frequent than intersexual interactions between the two species. Otherwise activity, including oviposition, was not altered by the presence of the other species. These studies indicate that L. osakensis has the potential to be a valuable addition to the natural enemies complex against A. tsugae. / Ph. D.
7

Field evaluation of a multi chamber pipe device for storm water treatment

Sant, Shachi January 2004 (has links)
No description available.
8

Evaluating the suitability of Laricobius nigrinus Fender (Coleoptera: Derodontidae), a biological control agent for hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae)

Lamb, Ashley B. 29 April 2005 (has links)
Hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), is an introduced pest injurious to hemlock trees (Tsuga spp.) in the eastern United States. HWA currently infests hemlock in over 50% of its geographic range and has the potential to spread throughout its entire range. Since HWA populations in the eastern United States are not regulated effectively by natural enemies (Wallace and Hain 2000), classical biological control is the most promising option for controlling this pest in the forest setting. This work evaluates Laricobius nigrinus Fender (Coleoptera: Derodontidae), a predator associated with HWA in western North America, is being evaluated as a potential biological control agent for HWA (Cheah et al. 2004). Observations suggest that natural enemies may help keep HWA populations below injurious levels in the western United States (Mausel, pers. comm.). Laboratory studies have revealed that L. nigrinus feed selectively on HWA and field studies in British Columbia, Canada have shown that its lifecycle is highly synchronous with HWA phenology. This predator is being further evaluated for its suitability as a biological control agent. In order to be a viable candidate, L. nigrinus must survive under natural field conditions in the eastern United States, reduce the density of HWA, and it must be amenable to mass rearing. The survival, reproductive capability and predator efficiency of L. nigrinus were assessed over 3 years in the field. In addition, the environmental factors regulating processes in the life cycle to develop and improve rearing procedures for this insect were identified. In the first year, adults survived from February - May, laid up to 41 eggs/beetle, and consumed approximately 4.3 adelgids per day. In the second season, L. nigrinus adults survived from November - April, laid up to 38 eggs/beetle and consumed approximately 4.5 adelgids per beetle throughout the study. In both seasons, adelgid populations were significantly lower on branches with predators than those without predators. This impact was demonstrated on both the winter and spring generation of HWA. The feasibility of caged field releases of L. nigrinus was determined in a third field study. An estimated 10, 000 L. nigrinus eggs were liberated in field cages in spring 2003. The density of adelgids in the subsequent (spring) generation of the adelgids was significantly lower on branches with larval activity than those with no predators. Despite extensive sampling, no F1 adults were observed, however F2 adults were recovered in the fall of 2004, 20 months after release. The L. nigrinus life stages incurring high mortality during rearing were identified and factors affecting survival in the feeding and non-feeding life stages were investigated. Studies on the survival and feeding of adults, length of ovipositional period, density per cage, and survival of larvae were conducted. The effect of type of pupation medium, moisture level, disturbance, soil sterilization, temperature, and photoperiod on survival of the non-feeding stages and time of emergence from aestivation was examined. The most noteworthy finding, regarding rearing, is that aestivation can be extended by storing adults at high temperatures and long daylength throughout the summer and decreasing the temperature and daylength in the fall. Based on the results of these studies, procedures for rearing L. nigrinus have been developed and it is currently being reared at two other institutions. To date, over 8, 000 adults produced at Virginia Tech have been released in 6 states and both F1 and F2 adults have been recovered from multiple locations. / Ph. D.
9

Sistema de gerência de pavimentos urbanos: avaliação de campo, modelo de desempenho e análise econômica / Urban pavement management system: field evaluation, prediction model and economic analyses

Zanchetta, Fábio 04 August 2017 (has links)
As vias pavimentadas se deterioram com o passar do tempo, por ação das cargas do tráfego e das intempéries. Por isso necessitam de intervenções (atividades de Manutenção e Reabilitação - M&R). No Brasil é mais comum que sejam realizadas apenas operações tapa-buracos e recapeamentos. São soluções sem eficiência técnica ou econômica. Uma alternativa mais racional e já em uso em países desenvolvidos é um Sistema de Gerência de Pavimentos Urbanos - SGPU. Os objetivos desta tese são apresentar uma propostas para avaliação da condição de vias urbanas com base na identificação dos defeitos da superfície do revestimento, um modelo de previsão de desempenho de vias urbanas com base em séries históricas obtidas no Município de São Carlos e uma análise econômica com a simulação de diferentes cenários para diferentes opções de M&R. Ainda como objetivos desta tese estão a apresentação das vantagens de utilizar um Sistema de Informações Geográficas - SIG, em uso no SGPU do Distrito Federal. Com base nos resultados encontrados, pode-se inferir que a avaliação de campo pode ser mais eficiente se forem considerados menos defeitos e os critérios de severidade e extensão forem fixados, com menos critérios subjetivos do avaliador. Considerando-se as estratégias de M&R adotadas pela Prefeitura Municipal de São Carlos e, ainda, de acordo com as avaliações de campo, pôde-se verificar que os pavimentos necessitam de Reforço Estrutural após 6 anos da sua construção. Os custos de manutenção, ao longo do tempo, são influenciados pela escolha da M&R a ser aplicada na preservação das vias e, também, pela época em que são realizadas, sendo as manutenções preventivas menos onerosas. Nos Estados Unidos, por exemplo, particularmente na cidade de San Antonio, Texas, são realizadas manutenções preventivas e, nas corretivas, há rigoroso controle de qualidade, o que não se verifica nas cidades brasileiras. Um SGPU possui critérios de análise de dados que, aliados ao Sistema de Informações Geográficas - SIG, garantem clareza na apresentação dos resultados, tanto em mapas temáticos quanto em gráficos e planilhas. Os relatórios no padrão SGPU possibilitam solicitar recursos federais e internacionais para manutenção viária, como o Programa Asfalto Novo do DF, que obteve, no ano de 2013, R$565 milhões para a pavimentação urbana. Em simulação de diferentes cenários de M&R, pôde-se concluir que a opção por tapa-buracos e recapeamentos é mais de duas vezes mais onerosa e mantém o pavimento em condição inferior ao que é possível com base nas técnicas de SGPU. Portanto, um SGPU proporciona benefícios socioeconômicos para toda a sociedade, com vantagens no médio e longo prazo e, ainda, mantém as vias em melhor condição. / The paved roads deteriorate over time, due to traffic loads and bad weather. Therefore, they need interventions (Maintenance and Rehabilitation activities - M & R). In Brazil, it is more common to carry out only hole-hole operations and resurfacing. They are solutions without technical or economic efficiency. A more rational alternative already in use in developed countries is an Urban Pavement Management System - UPMS. In this thesis proposals are presented for the evaluation of urban road conditions based on defects of the surface of the coating, a performance prediction model and an economic analysis with the simulation of different scenarios for different M & R options. Data were analyzed from the Municipality of São Carlos, in the State of São Paulo and the Distrito Federal - DF. Based on the results, it can be inferred that the field evaluation can be more efficient if less defects are considered and the criteria of severity and extension are fixed, with less subjectivity on the part of the evaluator. Considering the M & R strategies adopted by the municipal government of São Carlos and also, according to the field evaluations, it was possible to verify that the pavements have a useful life of 6 years. The maintenance costs, over time, are strongly influenced by the choice of M & R to be applied in the preservation of roads and also by the time in which they are carried out. In the United States, for example, preventive maintenance is carried out and, in the correctives, there is strict quality control, which is not the case in Brazilian cities. An UPMS has data analysis criteria that, together with the Geographic Information System - GIS, guarantee clarity in the presentation of results, both in thematic maps and in charts and spreadsheets. The reports in the UPMS standard make it possible to request federal and international resources for road maintenance, such as the DF Asphalt New Program, which obtained R$ 565 million for urban paving. In the simulation of different M & R scenarios, it was concluded that the option to cover holes and resurfacing is more than twice as expensive and keeps the pavement in a lower condition than is possible based on SGPU techniques. Therefore, an SGPU confers socio-economic benefits for the whole society, with advantages in the medium and long term, and also keeps the roads in better condition.
10

Investigating the rutting and moisture sensitivity of warm mix asphalt with varying contents of recycled asphalt pavement

Ahmed, Taha Ahmed Hussien 01 July 2014 (has links)
To evaluate the performance of Warm Mixture Asphalt (WMA) with varying amounts of recycled asphalt pavement (RAP) in comparison with Hot Mix Asphalt (HMA), comprehensive laboratory and field evaluations were conducted. Mix designs were performed for both WMA with a LEADCAP additive and HMA with large amounts of fractionated RAP materials. Hamburg Wheel Tracking (HWT) test was performed to evaluate the rutting and moisture susceptibility of both HMA and WMA laboratory mixtures. HMA mixtures with up to 50% RAP materials by binder replacement exhibited a better performance than WMA mixtures. However, when RAP materials were increased to 75% both WMA and HMA mixtures showed a superior performance. When a specially designed LEADCAP additive for a mixture with a high RAP content called "RAPCAP" was used, the performance was significantly improved. The existing Asphalt Bond Strength (ABS) test (AASHTO TP91-11) was modified to better evaluate the adhesion bond between asphalt binder and aggregate surface. Based on the modified ABS test results, it was found that the asphalt binder type significantly influenced the adhesion bond. To evaluate the performance of WMA mixtures in the field, test sections were constructed in Iowa, Minnesota and Ohio. The test sections were successfully constructed with less compaction effort than HMA and met the required field densities per each DOT's specification. All HMA and WMA mixtures collected from the test sections passed the HWT and the modified Lottman tests, which indicates high resistance to rutting and moisture damage. The asphalt binders were then extracted and recovered from the field samples then re-graded following AASHTO M320 and AASHTO MP19-10. The recovered asphalt binder grades were found to be higher than the target grades due to the existence of RAP materials in the mixtures except for asphalt binders extracted from WMA mixtures produced using "RAPCAP" additive.

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