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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

Intercepting contamination : improving the water quality of the Vaal river network through self-replenishing natural systems in an urban-rural landscape

Grala, Jani January 2016 (has links)
This dissertation's urban vision looks at the environmental issues of land, water and the health of the people of Vanderbijlpark, all of which have been affected by heavy industry. The study sets out to address the deteriorating quality of the Vaal River's water and how this is affected by the tributaries feeding into it. This dissertation will focus on the remediation and monitoring of the contaminated water through an ecosystemic approach. The programme involves the removal of heavy metals from the industrial effluent from the surrounding heavy industry that flows into the Rietspruit Canal. The potential of micro-organisms, plants and insects will be explored as elements of a natural treatment system of the contaminated water. The site identified for the remediation processes is an abandoned parcel of land - a remnant of the natural landscape after urban sprawl. The algae and wetland treatment system will run through the facility, becoming the spine for the remediation process and movement through the facility. The production of silk, its uses and by-products will be integrated to support the overall system which treats the contaminated water. The facility aims to address the community's need to express their voice on environmental and health issues by integrating a community auditorium and exhibition space. The construction and materiality is grounded in the premise that the local companies will remain supportive and collaborative in the environmental intervention in the Rietspruit Canal system, into which they contribute considerable effluent. It will also be proposed that the local companies will fund and supply various steel products for the construction of the intervention. This will form part of the company's corporate social responsibility and a way of giving back to fringe communities affected by industry. / Die stedelike visie vir hierdie verhandeling fokus op die omgewingskwessies van grond, water en die gesondheid van die mense van Vanderbijlpark wie almal geraak word deur swaar nywerhede. Die studie spreek die verswakkende kwaliteit van die Vaalrivier se water aan en hoe dit geraak word deur sytakke wat daarin vloei. Die verhandeling sal fokus op wyses waarop besoedelde water deur middel van 'n ekosistemiese benadering herstel en gemonitor kan word. Die program behels die verwydering van swaar metale uit die industri?le uitvloeisel van die omliggende swaar nywerhede wat in die Rietspruit-kanaal vloei. Die potensiaal van mikro-organismes, plante en insekte as elemente van 'n natuurlike stelsel vir die behandeling van die besoedelde water, word ondersoek. Die terrein wat geidentifiseer is vir die herstelprosesse is 'n verlate stuk grond, 'n oorblyfsel van die natuurlike landskap na stadspreiding. Die stelsel vir die behandeling van alge en vleilandhabitatte sal deur die fasiliteit loop en die ruggraat van die herstelproses vorm. Die produksie van sy en die gebruike en neweprodukte daarvan sal geintegreer word om die totale sisteem wat die besoedelde water behandel, te ondersteun. Die fasiliteit het ten doel om die behoefte van die gemeenskap om hul stemme oor omgewings- en gesondheidskwessies te verhef, aan te spreek deur die gemeenskapsamfiteater en uitstalruimte te integreer. Die konstruksie en materialiteit is gegrond op die veronderstelling dat die grootste staalnywerheid, ArcelorMittal, ondersteunend en samewerkend sal wees ten opsigte van die omgewingsingryping in die Rietspruit-kanaalsisteem, waartoe hul aansienlike uitvloeisel bydra. Daar sal ook voorgestel word dat die swaar nywerhede die befondsing asook verskeie staalprodukte vir die oprigting van die fasiliteit sal verskaf. Dit sal deel uitmaak van die maatskappy se korporatiewe sosiale verantwoordelikheid en is 'n manier om aan gemeenskappe wat deur die industrie geaffekteer word, terug te gee. / Mini Dissertation (MArch (Prof))--University of Pretoria, 2016. / Architecture / MArch (Prof) / Unrestricted
2

Novel Sensing and Inference Techniques in Air and Water Environments

Zhou, Xiaochi January 2015 (has links)
<p>Environmental sensing is experiencing tremendous development due largely to the advancement of sensor technology and wireless technology/internet that connects them and enable data exchange. Environmental monitoring sensor systems range from satellites that continuously monitor earth surface to miniature wearable devices that track local environment and people's activities. However, transforming these data into knowledge of the underlying physical and/or chemical processes remains a big challenge given the spatial, temporal scale, and heterogeneity of the relevant natural phenomena. This research focuses on the development and application of novel sensing and inference techniques in air and water environments. The overall goal is to infer the state and dynamics of some key environmental variables by building various models: either a sensor system or numerical simulations that capture the physical processes.</p><p>This dissertation is divided into five chapters. Chapter 1 introduces the background and motivation of this research. Chapter 2 focuses on the evaluation of different models (physically-based versus empirical) and remote sensing data (multispectral versus hyperspectral) for suspended sediment concentration (SSC) retrieval in shallow water environments. The study site is the Venice lagoon (Italy), where we compare the estimated SSC from various models and datasets against in situ probe measurements. The results showed that the physically-based model provides more robust estimate of SSC compared against empirical models when evaluated using the cross-validation method (leave-one-out). Despite the finer spectral resolution and the choice of optimal combinations of bands, the hyperspectral data is less reliable for SSC retrieval comparing to multispectral data due to its limited amount of historical dataset, information redundancy, and cross-band correlation.</p><p>Chapter 3 introduces a multipollutant sensor/sampler system that developed for use on mobile applications including aerostats and unmanned aerial vehicles (UAVs). The system is particularly applicable to open area sources such as forest fires, due to its light weight (3.5 kg), compact size (6.75 L), and internal power supply. The sensor system, termed “Kolibri”, consists of low-cost sensors measuring CO2 and CO, and samplers for particulate matter and volatile organic compounds (VOCs). The Kolibri is controlled by a microcontroller, which can record and transfer data in real time using a radio module. Selection of the sensors was based on laboratory testing for accuracy, response delay and recovery, cross-sensitivity, and precision. The Kolibri was compared against rack-mounted continuous emission monitors (CEMs) and another mobile sampling instrument (the ``Flyer'') that had been used in over ten open area pollutant sampling events. Our results showed that the time series of CO, CO2, and PM2.5 concentrations measured by the Kolibri agreed well with those from the CEMs and the Flyer. The VOC emission factors obtained using the Kolibri are comparable to existing literature values. The Kolibri system can be applied to various open area sampling challenging situations such as fires, lagoons, flares, and landfills.</p><p>Chapter 4 evaluates the trade-off between sensor quality and quantity for fenceline monitoring of fugitive emissions. This research is motivated by the new air quality standard that requires continuous monitoring of hazardous air pollutants (HAPs) along the fenceline of oil and gas refineries. Recently, the emergence of low-cost sensors enables the implementation of spatially-dense sensor network that can potentially compensate for the low quality of individual sensors. To quantify sensor inaccuracy and uncertainty of describing gas concentration that is governed by turbulent air flow, a Bayesian approach is applied to probabilistically infer the leak source and strength. Our results show that a dense sensor network can partly compensate for low-sensitivity or high noise of individual sensors. However, the fenceline monitoring approach fails to make an accurate leak detection when sensor/wind bias exists even with a dense sensor network.</p><p>Chapter 5 explores the feasibility of applying a mobile sensing approach to estimate fugitive methane emissions in suburban and rural environments. We first compare the mobile approach against a stationary method (OTM33A) proposed by the US EPA using a series of controlled release tests. Analysis shows that the mobile sensing approach can reduce estimation bias and uncertainty compared against the OTM33A method. Then, we apply this mobile sensing approach to quantify fugitive emissions from several ammonia fertilizer plants in rural areas. Significant methane emission was identified from one plant while the other two shows relatively low emissions. Sensitivity analysis of several model parameters shows that the error term in the Bayesian inference is vital for the determination of model uncertainty while others are less influential. Overall, this mobile sensing approach shows promising results for future applications of quantifying fugitive methane emission in suburban and rural environments.</p> / Dissertation
3

Factors that Shape Environmental Perceptions: the Role of Health and Place

Langlois, Elizabeth 15 December 2012 (has links)
Risk perception is the judgment people make about the characteristics and severity of a risk. Numerous theories and models exist which have identified the factors that influence risk perception. Among these factors, location, health status, and demographic characteristics are known to shape risk perception. To measure the influence of these factors on environmental perception, a series of surveys conducted in four Louisiana communities between 2004 and 2005 describe community perceptions about environmental issues and health status. The objective of the study was to characterize and compare environmental concerns relative to location, health status, and demographic characteristics. Results indicate that location has a strong influence in framing an individual’s concerns about environmental issues, particularly those living close to industry. Concern for general environmental and natural preservation issues were comparable among the communities indicating that concern for these issues is independent of residential location.
4

Evaluation of Weaning Stress in Beef Calves

Landa, Chelsea E. 19 July 2011 (has links)
Conventional techniques within the beef cattle industry involve weaning the calf from the dam when the calf is about 205 days of age. Weaning induces a stress-response that is implicated in reducing the health and productivity of newly weaned calves. Our goal was to evaluate the impact of weaning on the stress immune responses of beef calves. To that end, we 1) evaluated novel methods to quantify physiological markers of stress, 2) compared immune function and growth of calves grazing legume versus grass forages, and 3) compared the effects of abrupt versus two-stage weaning on calves. In study 1, calf, yearling, and adult beef cattle were used to assess the accuracy and precision of handheld glucometers in quantifying bovine blood glucose concentration. Precision Xtra® and ReliOn® glucometers were used chute side to quantify blood glucose concentrations in cattle and were compared to an accepted plasma glucose analysis on the same samples for validation. The Precision Xtra® glucometer was more accurate and precise than the ReliOn® glucometer. In study 2, weaned heifers were used to compare the immunomodulatory effects of grazing alfalfa versus fescue over a 30 day grazing period. No differences were detected in the interferon gamma (IFNγ) production and weight gain between the heifers on alfalfa and fescue. In study 3, effects of two-stage (fenceline) and abrupt weaning were compared. Calf weights, immune cell function, antibody production, blood glucose concentrations, fecal cortisol concentrations, and gene expression (FAS, IL-4,IL-10, and IFNγ) were measured pre- and post-weaning. On the day after weaning, the abruptly weaned calves had higher blood glucose concentrations than fenceline weaned calves. Fecal cortisol concentration and gene expression of FAS and IL-4 increased in both groups after weaning, but no differences were detected between the weaning treatments. Gene expression of IL-10 and IFNγ did not change over time. No date, treatment or treatment*date effect was detected for total weight gain or IFNγ production within the non-stimulated and the mitogen-stimulated whole blood samples. / Master of Science
5

Increases in Cortisol due to Weaning Stress and the Subsequent Alterations to Immune Function in Beef Calves

Gilbertie, Jessica 10 August 2010 (has links)
Weaning is defined as the physical separation of the cow-calf pair and the end of milk feeding. Natural weaning occurs between 7 and 14 months and is a gradual process. However, domestic weaning occurs between 6 and 8 months and occurs rapidly. Calves that are abruptly separated from their dam respond with increased vocalization and walking, and decreased eating and resting. The psychological stress the calf undergoes during weaning causes elevated glucocorticoid and catecholamine hormone concentrations that may predispose to increased morbidity and/or mortality from infectious diseases such as Bovine Respiratory Disease Complex. As an attempt to counter these changes, alternative weaning methods have been implemented and normally occur in two stages. Two-stage weaning begins with the cessation of milk feeding for approximately one week with the calf maintaining some contact with their dam and then permanent separation occurs. One of these methods uses a single fence to separate the cow-calf pair; this process allows the calf to see, hear and smell their dam, but does not allow the calf to suckle from its dam. Increases in cortisol, a glucocorticoid, have been linked to immunological alterations. Most notably, elevated cortisol concentrations decrease neutrophil function by down regulating the gene expression of CD62L and Fas. Cortisol also alters lymphocyte phenotype by decreasing ?δ T cells and increasing°? T cells in the circulation. Lastly, increases in cortisol can modify T cell cytokine production. The cytokines IL-12 and IFN? are secreted from T helper 1 cells while T helper 2 cells secrete IL-4 and IL-10; these T cells subsets also inhibit one another. During higher cortisol concentrations, these T cells are biased toward T helper 2 cytokine production. All these changes in immune function can lead to increased susceptibility to disease around the time of weaning. Therefore, two trials were conducted to test the hypotheses that abrupt weaning results in elevated concentrations of cortisol and subsequently alters immunological functions, and that fenceline weaning alleviates the increase in cortisol and alterations to immune function associated with weaning. In the fall of 2008, 12 Angus and Angus-X heifers (186°21 kgs; 174°16 days of age) were blocked by age and weight and randomly allotted into two groups, fenceline and abrupt. Blood samples were taken on day -7, 0, 7, 14, 21, and 42; fecal samples were taken on day -7, 0, and 3. All calves were weighed on day -7, 0, 7, 14, and 42. On day -1 all calves were separated from their dam and transported for 2 hours to another facility. On day 0 all calves were vaccinated with Brucella abortus (strain RB51). Serum was analyzed for IFN? and IL-4 as well as IgG1 and IgG2 specific antibodies to RB51. Fecal samples were analyzed for cortisol metabolites. Both IgG1 and IgG2 antibodies to RB51 increased from day 0 to day 14 (P<0.05), however no differences were detected between treatment groups. Fecal cortisol metabolites were higher on day 0 in abruptly weaned calves (P< 0.001) but did not differ between groups on day -7 or day 3. Fenceline calves had higher concentrations of IFN? in the serum on day -7 and day 0 as compared to the abruptly weaned calves (P<0.04). In the fall of 2009, forty-four Angus and Angus-X calves (19 heifers and 25 steers; 181°27 kgs; 148°17 days old) were blocked by age and gender and randomly allotted within block into two treatment groups, fenceline (FL) and abrupt (AB). Approximately half the fenceline calves were separated from their dams by a single fence at day -7 and the rest of the fenceline group at day -6; all calves were removed from their dam at day 0. Calves were vaccinated with Histophilus somni on day 1. Blood samples were taken at day -6, 1, 3, 8, 15, and 22. Fecal samples were taken on day -7, -6, 1 and 3. All calves were weighed on day -7, 0, 8, and 22. Serum samples were analyzed for IgG1 and IgG2 specific-H. somni antibodies, white blood cells were analyzed for lymphocyte phenotypes, and gene expression using 18S as the housekeeper gene. Fecal samples were analyzed for cortisol metabolites. Abruptly weaned calves had higher concentrations of cortisol metabolites in the feces than fenceline calves at day 1 (P<0.0001). No difference in average daily gain or H. somni specific antibodies between treatment groups was detected. There was a treatment*date interaction in lymphocyte and neutrophil populations (P<0.05); neutrophils from fenceline calves dropped from day -6 to day 1, but increased from day 1 to day 3, while abrupt calves decreased from day -6 to day 3. Lymphocytes from fenceline calves increased from day -6 to day 1, but decreased from day 1 to day 3, while lymphocytes from abrupt calves increased from day -6 to day 3. No difference in treatment groups was detected for lymphocyte phenotypes or gene expression; however, a date effect was detected. The CD4 and CD8 cell populations increased over time (P<0.0001) and WC1 and TcR1 decreased over time (P=0.0243 and P=0.0027 respectively) for both treatment groups. A decrease was detected over time for expression of GAPDH and CD62L (P<0.0001). The gene expression for the cytokines IFN?, IL-4 and IL-10 had no change over time. Results from the two studies suggest that fenceline weaning decreases the cortisol response associated with cow-calf separation, but does not have a significant effect on immunological parameters measured in this study. / Master of Science
6

The Great Mysterious

Sayers, Jeremy H. 20 May 2010 (has links)
No description available.
7

Contesting Risk, Expertise, and Environmental Justice on the Fenceline: The Cases of the Navajo Nation, Radford Arsenal, and Camp Minden

Nelson, Gregory Douglas 14 September 2016 (has links)
This dissertation examines the contestations over the politics of knowledge, risk, and environmental justice in three fenceline sites. Mobilizing the fenceline standpoint to study risk strengthens our objective understanding of the social situatedness of risk. To illustrate how a fenceline standpoint contributes to stronger objectivity of risk contestations, I survey public discourse of coal slurry extraction in Black Mesa, Arizona using an environmental justice framework. Discursive justifications for the construction of the slurry pipeline reveal how environmental injustice in the fenceline community emerged through urban controversies over water and power generation that excluded a fenceline standpoint. Insights from Black Mesa frame the next two cases: open burning hazardous waste at Radford Army Ammunition Plant, and M6 Disposal at Camp Minden, Louisiana. At Radford, scholar-activist research examines the contestations of risk at one of the most hazardous waste facilities in the nation. I analyze the construction of risk from open burning of hazardous waste from a fenceline standpoint. I discursively situate the controversy over fenceline community risk from open burning, by showing the inadequacies of official risk assessments. Critical discourse analysis of risk shows the extant contestations over the practice of open burning. In juxtaposition to Radford, the Camp Minden open burn controversy demonstrates how a fenceline movement successfully constructed alternatives to open burning. Fenceline success in Minden is forcing scrutiny over the risks produced by the practice of open burning explosives across the United States. The activation of fenceline knowledge and expertise, through grassroots organizing, is propelling inquiry from scientific and technical experts of the American Chemical Society who are questioning why the Department of Defense and the Environmental Protection Agency have approved the use of open burning at other sites despite safer alternative technology. Synthetically, each case illustrates the importance of fenceline knowledge as a crucial site of expertise. I present an argument for how a fenceline standpoint can challenge regulatory and producer constructions of fenceline risk. The creation of a program of research: Critical Risk Analysis, offers a model for scholar-activist intervention on the fenceline. The Camp Minden Dialogue demonstrates a successful example of how fenceline expert-activists can influence the construction of risk. Normatively, I build the argument that environmental justice research within Science and Technology Studies ought to situate the fenceline standpoint as equal to the competing epistemological claims of production and regulatory experts in order to strengthen the objectivity of our research in contested fenceline sites. / Ph. D.

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