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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.
71

Linking In-Situ Data with Remote Sensing to Analyze Tropical Glacier Stability and Retreat in the Cordillera Blanca, Peru

Santos, Chandler H 01 July 2016 (has links)
Glaciers are a major source of freshwater around the world, but they are melting at an increased rate due to atmospheric warming resulting from anthropogenic climate change. In addition to temperature increases, light-absorbing particulates on glaciers also are contributing to glacial melt. This research examines how black carbon, released into the air through partial combustion of biofuels, is affecting the surface albedo of glaciers. I also delineate possible sources of black carbon in the Cordillera Blanca region of Peru. Ground data were collected each year from 2011 to 2013 during the local dry season. Effective black carbon (eBC) values were determined using the Light Absorption Heating Method and satellite-derived albedo values were retrieved from NASA’s MODIS MOD10A1 data. Effective black carbon (eBC) values and albedo levels were moderately correlated, showing that albedo decreases with an increase of black carbon, and that this impact can be measured using satellite instruments. Values of eBC did not correlate with spatial proximity to mines, but did correlate with proximity to Huaraz, which likely is the major source of light-absorbing particulates in the region. Further research would benefit from a more extensive source dataset and surface albedo measurements over different seasons.
72

Short-term variation during asbestos abatement activities

Jones, Erle Baxter, 1953- January 1987 (has links)
The fibrous aerosol monitor (FAM) was designed to count fibrous particulates as accurately as the standard method, P & CAM 239, now NIOSH 7400. The Hi-Vol (HV) method, a modification of the standard method, was developed to collect fibers over a shorter time interval (i.e., 10-minutes) with the same accuracy as the standard method. The current study sought to compare the HV method with the FAM to assess its validity in measuring airborne asbestos levels and to assess the importance of short-term variation in asbestos levels in determining appropriate respiratory protection. Correlation between the FAM and HV showed a poor linear relationship in all comparison studies. However, there was good correlation between the average of short-term HV samples and long-term time-weighted average (TWA) samples at reported low levels of airborne asbestos. All membrane filter techniques showed strong correlation with each other, but were weakly correlated with the FAM. (Abstract shortened with permission of author.)
73

A program translator software solution for remote data acquisition

Greenberg, Robert Joseph, 1957- January 1987 (has links)
A software solution was developed for remote data acquisition applications, i.e., applications where line power is unavailable. The solution was developed in response to a lack of suitable software for environmental measurements using battery powered computers. The software solution is in the form of a program translator that creates programs dedicated to specific remote data acquisition applications from a dialect governed by specific rules. A methodology is presented for defining real-time measurement applications based upon three time components: a scanning interval, an average period, and an averaging interval. The software solution is termed ADAPT, an acronym for 'All-purpose Data Acquisition Program Translator'. ADAPT was written for a Hewlett-Packard hand-held computer, the HP-71, and a Hewlett-Packard data acquisition system, the HP-3421A. The methodology and algorithms may be applied to other computer and data acquisition systems.
74

Airborne concentrations of formaldehyde in a pathology unit

Ntsuba, Hlosi Samuel 19 January 2012 (has links)
Background This descriptive cross-sectional study aimed to assess the exposure to formaldehyde associated with the tasks in a pathology laboratory unit. The study objectives were to describe the tasks involving the use of formaldehyde in the unit and assess exposure to formaldehyde as well as assess the effectiveness of existing engineering/ventilation system control methods. Methods The study involved observation and description of all tasks carried out in the laboratory, assessing exposure to formaldehyde and physical measurements of laboratory parameters such as area and volume. Exposure assessment involved three levels: task-based exposure assessment; personal exposure assessment and area exposure assessment. Formaldehyde measurements, by means of shadow sampling (personal breathing zone sampling by another person shadowing person being sampled) were taken using the formaldehyde meter. Data were summarised using means, medians and proportions and results were presented in figures and tables. For significance testing, an analysis of variance was carried out on the log-transformed data and p-value less than 0.05 were interpreted as statistically significant. Results Not all tasks in the laboratory were done according to the standard operating procedures. In general, exposure to formaldehyde was highest among the assistants group who were mostly responsible for high-exposure tasks. Mean STEL values for assistants, technologists and pathologist were 2.37ppm, 1.21ppm and 1.59ppm respectively, while for TWA, the figures were 0.60ppm, 0.36ppm and 0.21ppm. For short term exposures (STEL and peak values) pathologist exposure levels were higher than those of technologists while technologists were higher for long term exposures (daily exposure and 8-hour TWA). Daily exposure varied significantly for assistants and technologists but not for pathologist. Despite the use of engineering exposure controls for formaldehyde, 27/28 of all tasks were higher than the ACGIH threshold ceiling limit of 0.3ppm, 0.008ppm MRL value and 0.002ppm RELTWAConclusion The results have shown exposures among the employees of all job categories in this study, with laboratory assistants being the most exposed. Currently installed local ventilation system requires to be upgraded in accordance with best practices of 3.5m/s for air speed. Training, on PPE usage together with the medical surveillance should also be implemented. value.
75

A user needs assessment of the state of the environment (SOE) report for the City of Cape Town

Jennings, Lize January 2004 (has links)
Thesis (MTech( Environmental Health))-- Cape Technikon, Cape Town, 2004 / The City of Cape Town (CCT) produced its first State of Environment report in 1999 as part of their Integrated Metropolitan Environmental Policy (IMEP) development process. The first report was developed by the City's Environmental Management Department, assisted by the Environmental Evaluation Unit at the University of Cape Town. It was developed through a synthesis of the findings of specialist baseline studies, information gathered from literature reviews, issues and indicators workshops and consultation with other specialists and authorities in order to obtain a suitable reporting approach and structure. Every year, the progress in each theme is assessed in the SoE report through the collection of information. This information is compared to the information in the previous year's SoE report and long-term trends are identified. The CCT has been producing the SoE report since 1999 and has to date produced five full reports and four accompanying summary reports. There is however limited knowledge of who the users of this report are as well as how they use the report in the future. This study attempts to provide the CCT with a better indication of the answers to these questions. The sample group was limited to those users with e-mail addresses. The data for this study were collected through a questionnaire sent to all the individuals and organisations on the IMEP database who received the SoE report in the past five years. The questionnaire asked the users how they used the report, what they liked and didn't like about the reports and how the report could be improved in order to meet their information needs and requirements. The report is used by a number of different sectors of society, especially individuals from government departments. There is however a need to reassess a number of the aspects of the report. These include the use of technical language in the summary report, the gap between the full and summary reports, the needs of the different users, the use of different products and which products are suitable for the different users, the need for a more interactive website, the need for the information in the report to be up-to-date and the assessment of the themes and indicators.
76

Captive Environmental Influences on Behavior in Zoo Drills and Mandrills (Mandrillus), a Threatened Genus of Primate

Terdal, Erik 01 January 1996 (has links)
Drills (Mandrillus leucophaeus) are an endangered species of African monkey (Cercopithecidae), and their sole congener the mandrill (Mandrillus sphinx) is vulnerable to extinction. Both species are threatened in the wild by deforestation and hunting. Drills have a poor record of captive reproduction. Many individuals appear to have behavioral deficiencies which interfere with reproduction. Thus, the zoo population of drills does not serve as a “hedge” against the species’ total extinction: drills are endangered in captivity as well as in the wild. Mandrills, by contrast, reproduce well in captivity. Information on the behavior of mandrills in captivity may help zoo managers improve husbandry for both species. The intent of this research was to study the relationship between aspects of the captive environment and behaviors which lead to reproduction. A review of the literature on both drills and mandrills, in the wild and captivity, was used to suggest “essential characteristics” of the captive environment that may encourage animals of both species to engage in natural, active behaviors, to form cohesive dyads with opposite-sex adults, to develop affiliative bonds, and to engage in sexual behavior. Sixty-two drills and mandrills in 14 groups in the U.S. and Germany were studied with behavior sampling methods, using the Drill Species Survival Plan ethogram. Data were analyzed by multiple regression using transformed variables. No over-all species differences in behavior were found. Results suggested that two factors promoted natural activity: 1) environmental enrichment which provides positive reinforcement for active behaviors, and 2) an affiliative husbandry style by the animal’s keepers. Active animals were more likely to engage in social behaviors leading to copulation. Many of the non-reproducing drills appeared to be “passive and withdrawn,” and shared a constellation of signs that appeared to be analogous to human clinical depression. An etiological model for “passive and withdrawn” Mandrillus, based on biobehavioral theories of human depressive disorders, was developed to link early rearing conditions and environmental enrichment. This model was then used to develop a historic-demographic hypothesis for why mandrills have historically had greater reproductive success than drills in zoos.
77

Some Relationships Between Sedimentary Trace Metal Concentrations and Freshwater Phytoplankton and Sedimentary Diatom Species Composition

Vogel, Allan Hayes 01 January 1995 (has links)
Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation procedure. The summer epilimnetic filterable concentration of an eighth (Mo) was also determined. Sedimentary diatom remains and summer phytoplankton populations of the lakes were correlated with the 22 metal parameters and with conservative water chemistry parameters, estimators of lake productivity, and watershed geology. Both the sedimentary metals and the two populations of primary producers correlated best with the ecoregions of Omernik and Gallant (1986). A number of species possessed correlations with specific trace metal extractions or ratios of those extractions. Bloom-forming Anabaenas strongly correlated with sedimentary organic and filterable epilimnetic nickel. Possible Ni limitation of this group was observed in one Cascade lake (Lava). The ratio of organic nickel to cobalt appeared to control the abundance of several sedimentary diatoms. Organic vanadium strongly correlated with a number of diatoms, particularly in the genera, Cyclotella and Fragilaria. Possible V pollution was observed in one lake (Woahink), and frustule remains of C. stelligera significantly increased with increasing total sedimentary V concentrations there. Zinc was the trace metal most frequently found to apparently limit diatom growth. Diatoms may have developed three different responses to Zn limitation; the three groups have been labelled affinity-, velocity-, and (possibly) storage- specialists following Sommer (1985). Possible Zn pollution was observed in two lakes (Oswego and Clear). Phytoplankton and sedimentary diatoms weakly correlated with sedimentary iron by comparison to Ni, V, or Zn. Few strong relationships were observed with manganese, copper, or cobalt. No statistically significant correlations were found with molybdenum, and few correlations between a conservative chemical parameter and a species of phytoplankton were found. There was poor correlation between trace metal concentrations and lake productivity, despite frequently observed correlations between individual species and particular trace metal fractions. These findings suggest that variations in absolute trace metal concentrations, and/or ratios, may be important factors for controlling species distribution, but have relatively little influence upon lake primary productivity or standing stocks.
78

Biogeochemical techniques for environmental monitoring and mineral exploration : a case study at the Temora Gold Mine

Huang, Xiaoyan, n/a January 1998 (has links)
Biogeochemistry has been utilized successfully in Australia as a regional or fellow-up geochemical exploration techniques in the arid terranes of Australia. This Master's study is based on the biogeochemistry approach, which relies on the chemical analysis of plant tissues to obtain information on the geology and geochemistry of the underlying rocks. The project involved the systematic sampling and chemical analysis of plant materials and the supporting soils to establish the suitability of using particular tree species for environmental monitoring and their potential as a sample medium in geochemical exploration in the vicinity of the Temora Gold Mine, NSW, Australia. Working on 168 plant tissues (leaves, twigs and bark) in 54 plants species from 8 families at the three sites of background area, mineralized area and tailings area, and 54 supporting soil samples from three strata of 0-5 cm, 20-30 cm, and 30-40 cm, found that there was a good agreement between soil geochemistry and plant geochemistry on the result of a strong geochemical association between Au and As. The As-Au pattern was suggestive of the presence of the Au-As mineralization. Black cypress pine (Callitris endlicheri) LEAVES show a higher ratio of Asminjn/Aumin in the mineralized area than ASbkg/Aubkg in the background area, up to 7 times. The research finding suggests that the LEAVES of Black cypress pine (Callitris endlicheri) have a potential to be a biogeochemical sample medium as better indicators for Au. Golden wattle (Acacia pycnantha) BARK and Yellow box (E. melliodora) BARK appear to be better indicators for Au but more research is required. The most occurrence of anomalies of As, Au, Sb, Cu and Fe were found in Red box (E. polyanthemos) BARK. Red box (E. polyanthemos) BARK may have the potential to be an Au indicator in the area when Red box (E. polyanthemos) is present. Results on test-tolerant plants show that Eucalyptus species: Red box (E. polyanthemos), Coral gum (E. torquata), and Yellow box (E. melliodora) have a higher rate of uptake trace elements from the tailings soils. Therefore, Eucalyptus family generally adapted to metal-rich soils and can be used as cleaning-up indicators and environmental monitors for the tailings area of metal contaminated soils in the Temora Gold Mine.
79

Seasonal Variations in Fish Assemblages of Small Warmwater Streams in Four Southeastern National Parks

Zimmerman, Joseph Carl 01 May 2007 (has links)
Small warm-water streams in the southeastern United States experience significant differences in temperature, as well as changes in physical parameters due to seasonal fluctuations. It has been generally thought that fish assemblage patterns change as a direct result of these seasonal variations. This study was designed to determine the effects of variable flow regimes on fish species composition, diversity, and abundance. Eight small warm-water streams in four national parks (Chickamauga and Chattanooga National Military Park, Fort Donelson National Battlefield, Abraham Lincoln Birthplace National Historic Site, and Russell Cave National Monument) were sampled May-June 2005 for the summer trials, October-November 2005 for the fall trials, and April 2006 for the spring trials. All trials were conducted when water levels and flows were at normal seasonal stages. Fish populations were determined by electrofishing a 100-m reach at each site. Physical parameters including temperature, dissolved oxygen, conductivity, pH, and flow rate were also measured at each site. From summer to fall, the majority of the streams decreased in flow until temporary pools were formed. The lack of flow caused increased temperatures, decreased dissolved oxygen, and increased conductivity levels. As a direct result, overall fish abundance and diversity values decreased. From fall to spring, all the streams increased in flow, which brought back the riffle to pool habitat sequences. Dissolved oxygen levels increased, conductivity levels decreased, and temperatures became more stable. As a result, overall fish abundance and diversity values increased. Results indicated that fish assemblage patterns in the four parks did change as a direct result of the seasonal variations in habitat and water quality.
80

Determination of trace elements in iron-manganese oxide coatings by laser ablation ICP-MS for environmental monitoring/mineral exploration /

Huelin, Sheldon Richard, January 2005 (has links)
Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Includes bibliographical references.

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