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Evaluation of Rainwater Harvesting on Residential Housing on Virginia Tech CampusMcCloskey, Tara 27 May 2010 (has links)
Rainwater harvesting (RWH) refers to the collection of rainwater for subsequent on-site use. Rainwater is most often used for non-potable purposes including toilet flushing, laundering, landscape and commercial crop irrigation, industry, fire fighting, air-conditioning, and vehicle-washing. This study evaluates the potential impacts of RWH on residential housing on Virginia Tech campus in southwestern Virginia in regards to potable water offset, energy conservation, stormwater mitigation, carbon emission reduction, and financial savings. Potential rainwater collection was estimated from three simulations used to approximate the maximum, average, and minimum range of annual precipitation. Collected rainwater estimates were used to calculate the impacts on the areas of interest. Cumulatively, the sample buildings can collect 3.4 to 5.3 millions of gallons of rainwater — offsetting potable water use and reducing stormwater by an equivalent amount, save 320 to 1842 kWh of energy, and reduce carbon emissions by 650 to 3650 pounds annually. Cumulative savings for the nine buildings from combined water and energy offsets range between $5751 and $9005 USD, not substantial enough to serve as the sole basis of RWH implementation on campus. A significant advantage of RWH relates to the management and improvement of the Stroubles Creek watershed in which the majority of the campus sits. Additionally, RWH implementation would benefit sustainable initiatives and provide Virginia Tech additional opportunities for conservation incentives and environmental stewardship funding. / Master of Science
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Soil Erosion and Modeling Following Closure Best Management Practices for Bladed Skid Trails in the Ridge and Valley RegionVinson, Joseph Andrew 01 July 2016 (has links)
Sediment is a prevalent non-point source pollutant associated with forest operations. Roads and skid trail surfaces have erosion rates that are greater than the harvest area. Forestry best management practices (BMPs) have been developed to minimize erosion on skid trails, but few projects have compared the effectiveness of different BMPs for bladed skid trails in the mountains. This project evaluated soil erosion rates from bladed skid trails in the Ridge and Valley physiographic region of Virginia following an operational timber harvest. Skid trails were assigned into six blocks where each block had similar slopes and soils. All BMP treatments had waterbars, which are considered the minimum acceptable BMP closure treatment. Each block contained four different skid trail closure BMP treatments (waterbar only (Control), slash-covered (Slash), seeded (Seed), and seeded with fertilizer and mulch (Mulch)). The 24 treatment units were isolated with waterbars and installed following the Virginia Department of Forestry (VDOF) BMP guidelines. The randomized complete block design had three slope class ranges: gentle (0%-10%), moderate (11%-20%), and steep (21%-30%). Stormwater runoff from skid trails was directed at downslope waterbars and eroded material was trapped in silt fences at each treatment area. Depth and area of eroded soil collected in silt fences was measured monthly to quantify total erosion volume for the skid trail area and converted to a per acre basis. Volumes were converted to mass using soil bulk density within the trapped sediment. Control treatments had an average erosion rate of 6.8 tons ac-1 yr-1, with rates up to 73.5 tons ac-1 yr-1 following installation and during extreme rainfall events. Seed treatments recorded an average erosion rate of 2.6 tons ac-1 yr-1, with rates reaching 27.2 tons ac-1 yr-1. Adding grass seed provided ground cover, but not consistently over time. Due to high rates of ground cover, the Mulch treatments averaged 0.5 tons ac-1 yr-1 with an extreme of 3.8 tons ac-1 yr-1. Slash treatments were found to reduce erosion rates to an average of 0.4 tons ac-1 yr-1, with the highest rate being 1.8 tons ac-1 yr-1. Site characteristics on experimental units were collected quarterly in order to model erosion rates with commonly used erosion models for forestland (USLE-Forest, RUSLE2, WEPP:Road). Direct erosion estimates were compared to erosion model predictions produced by USLE-Forest, RUSLE2, and WEPP:Road in order to partially confirm the relationship between sediment trap data and the models. Using multiple analyses it was determined that USLE-Forest and RUSLE2 predicted mean values that are more similar to the actual measured rates, RUSLE2 and WEPP:Road have better linear relationships to the measured rates than does USLE-Forest, and USLE-Forest was the most statistically similar to the measured data using a nonparametric Steel-Dwass Multiple Comparisons Test. All models performed inadequately when attempting to predict Control or Slash treatments; while all models performed the best at predicting Mulch treatments. / Master of Science
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Applicability of Stormwater Best Management Practices in the Virginia Coastal PlainJohnson, Rachael Diane 06 June 2016 (has links)
The Virginia Runoff Reduction Method (RRM) was adopted in 2014 as a compliance tool for evaluation of stormwater volume and quality, and necessitates use of urban stormwater best management practices (BMPs) to meet regulatory standards. Coastal Virginia is characterized by flat terrain, shallow water tables, and low permeable soils that may limit the application of BMPs as recommended by state regulations. Soil morphological features are often used to estimate the seasonal high water table (SHWT) for initial feasibility, but existing soil data misrepresented expected SHWT depths in the Virginia Beach, VA, study area. A GIS-based methodology relying on perennial surface water elevations and USGS groundwater monitoring data was developed to estimate the SHWT depth in Virginia Beach. The SHWT map was shown to be consistently more reliable than available predictions based on soil morphology, and was used as input to a BMP siting tool. The tool, known as BMP Checker, was developed to explore how flat terrain, shallow water tables, and poor soils influence BMP siting in coastal Virginia. The BMP Checker algorithm was validated on 11 Virginia Beach sites before application on 10,000 ft2 (929 m2) area sections across the city. Citywide application showed that the most widely applicable BMPs in the study area include wet ponds that intercept groundwater and constructed wetlands. Conversely, sheet flow to conservation area and infiltration practices are the least applicable. Because the RRM assigns more credit to infiltration-based practices, sites in Virginia Beach may find it difficult to meet regulatory standards. / Master of Science
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Evaluation of the Design of a Family Practice Healthcare Clinic Using Discrete-Event SimulationSwisher, James R. 23 April 1999 (has links)
With increased pressures from governmental and insurance agencies, today's physician devotes less time to patient care and more time to administration. To alleviate this problem, Biological & Popular Culture, Inc. (Biopop) proposed the building of partnerships with healthcare professionals to provide high-quality, cost-effective medical care in a physician network setting. To assist Biopop in evaluating potential operating procedures, a discrete-event simulation model has been constructed. The model is built in an object-oriented, visual manner utilizing the Visual Simulation Environment (VSE). The model examines both internal Biopop operations and external clinic operations. The research presented herein describes the design of the simulation model and details the analysis of the clinical environment.
A methodology for determining appropriate staffing and physical resources in a clinical environment is presented. This methodology takes advantage of several simulation-based statistical techniques, including batch means; fractional factorial design; and simultaneous ranking, selection, and multiple comparisons.
An explanation of the experimental design is provided and results of the experimentation are presented. Based upon the experimental results, conclusions are drawn and recommendations are made for an appropriate staffing and facility size for a two-physician family practice healthcare clinic. / Master of Science
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Performance Analysis of an Urban Stormwater Best Management Practice RetrofitSimko, Andrew Jack 22 September 2014 (has links)
Historically, the primary objective of traditional stormwater best management practices (BMPs) was to attenuate peak runoff discharges from urban areas. There has been growing demand to construct BMPs that improve stormwater runoff quality to reduce pollutant loading into downstream water bodies. A BMP located in Herndon, Virginia was retrofitted in 2009. Previously a dry detention pond, the new BMP design contains permanent wet pools as well as elements of Low Impact Development practices. A performance analysis was conducted on the retrofit to determine if the BMP was removing pollutants from stormwater runoff. Two mass-based methods were utilized for the performance analysis: the Summation of Loads Method and Effluent Probability Method. The Kaplan-Meier method and Robust Regression on ordered statistics (ROS) were used to make it possible to include censored datasets in the analysis. Analysis with the SOL method showed removal of suspended sediment, nitrogen, iron, and copper. Export of dissolved solids, phosphorus, organic carbon, and manganese was observed. The results of the Effluent Probability Method showed statistically significant reductions of sediment, iron, and copper across the entire range of monitored storm event sizes (p-value≤0.05). There was no statistical difference between the influent and effluent loads of nitrogen. Negative performance of dissolved solids, phosphorus, organic carbon, and manganese were observed for the entire range of monitored storm event sizes. The results of both methods indicated that the BMP retrofit is effectively removing sediment but failing to achieve significant nutrient reductions. This may be due to the creation of anoxic conditions from the oxygen demand of the micropool sediments and microbial degradation of vegetation within the BMP. Removal of the sediment bed and harvesting of the vegetation would likely improve the performance of the BMP. / Master of Science
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Network Roadway Surface Friction and Its Usage to Improve Safety and Project Performance along West Virginia HighwaysMusick, Ryland Wayne Jr. 17 December 2019 (has links)
Roadway surface friction along the West Virginia Division of Highways' roadway network is key to the safety of all traveling motorists. Being geographically located in the rugged Appalachian Mountains, the West Virginia Division of Highways' roadway network is flooded with innumerable geometric and design challenges, causing drivers to have to exercise the most care and attention when navigating the network.
This dissertation introduces the concept of roadway surface friction management to this network. For decades, roadway surface friction has only been tested and checked on an as-needed basis at crash sites and intersections, in legal situations, and pavement acceptance on construction projects. It also seeks to use the acquired data through a case study to insure proper methodology of roadway surface friction management, to develop sample safety performance functions and best crash estimates, and to apply this decision-making data to provide assistance and guidance in the selection of projects in the West Virginia Highway Safety Improvement Program.
This dissertation follows the manuscript format and is composed of three papers. The first chapter of the dissertation examines the usage of Method 3 of the AASHTO Guide for Pavement Friction and the modifications to this method to collect existing roadway surface friction data along the District Ten portion of the network.
The second chapter of the dissertation discusses the development of sample safety performance functions to estimate the average number of crashes along each of the tested roadway categories: Interstate Routes, United States Routes, and West Virginia Routes. It also discussed the development of best crash estimates using the Empirical Bayes Method. This is essential to be able to forecast how crash counts should improve, given the application of various roadway improvements.
The third and final chapter of the dissertation develops the case study based on the District Ten portion of the network and shows how to enhance project selection in the West Virginia Highway Safety Improvement Program. This is completed by applying the safety performance functions and best crash estimates from the second chapter to arrive at real friction numbers for the network and their project impacts. / Doctor of Philosophy / Roadway surface friction along the West Virginia Division of Highways' roadway network is key to the safety of all traveling motorists. Being geographically located in the rugged Appalachian Mountains, the West Virginia Division of Highways' roadway network is flooded with innumerable geometric and design challenges, causing drivers to have to exercise the most care and attention when navigating the network.
This dissertation introduces the concept of roadway surface friction management to this network. For decades, roadway surface friction has only been tested and checked on an as-needed basis at crash sites and intersections, in legal situations, and pavement acceptance on construction projects. It also seeks to use the acquired data through a case study to insure proper methodology of roadway surface friction management, to develop sample safety performance functions and best crash estimates, and to apply this decision-making data to provide assistance and guidance in the selection of projects in the West Virginia Highway Safety Improvement Program.
This dissertation follows the manuscript format and is composed of three papers. The first chapter of the dissertation examines the usage of Method 3 of the AASHTO Guide for Pavement Friction and the modifications to this method to collect existing roadway surface friction data along the District Ten portion of the network.
The second chapter of the dissertation discusses the development of sample safety performance functions to estimate the average number of crashes along each of the tested roadway categories: Interstate Routes, United States Routes, and West Virginia Routes. It also discussed the development of best crash estimates using the Empirical Bayes Method. This is essential to be able to forecast how crash counts should improve, given the application of various roadway improvements.
The third and final chapter of the dissertation develops the case study based on the District Ten portion of the network and shows how to enhance project selection in the West Virginia Highway Safety Improvement Program. This is completed by applying the safety performance functions and best crash estimates from the second chapter to arrive at real friction numbers for the network and their project impacts.
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Surface and groundwater quality impacts of conservation tillage practices on burley tobacco production systems in Southwest VirginiaLaird, Megan K. 04 March 2004 (has links)
This study measured sediment, nutrient and pesticide edge-of-field and deep percolation losses from conventional tillage (CT), strip tillage (ST), and no-till (NT) treatments in a burley tobacco production system. The field experiment results show that the CT treatment yielded more total runoff, 93.6 mm, than ST and NT. Compared to the CT treatment, ST reduced the total mass loss of NO₃⁻ by 37 percent, NH₃ by 54 percent, PO₄³⁻ by 12 percent, TP by 65 percent and TSS by 64 percent. The NT treatment reduced the total mass of NO₃⁻ by 49 percent, NH₃ by 46 percent, PO₄³⁻ by 17 percent, TP by 73 percent and TSS by 77 percent. Field experiment results showed that, respectively, the ST and NT treatments yielded 77 and 82 percent less chlorpyrifos, an insecticide, mass loss in runoff compared to CT. With respect to flumetralin loss, a growth inhibitor, the NT treatment yielded 30 percent less and ST yielded 6.8 percent more flumetralin mass, compared to CT.
The percolated water results show that compared to the CT treatment, ST resulted in 33 percent less NH₃, 7.5 percent less TKN, and 39 percent less PO₄³⁻ total mass. The NT treatment yielded 41 percent less NH₃ and 20 percent less TKN total mass loss compared to the CT treatment. The NT treatment had the most NO₃⁻, PO₄³⁻, and TP mass loss below the root zone, however NT also had the most percolated water by 53 mm (838 L). The ST treatment yielded 77 percent less, and NT yielded 82 percent less chlorpyrifos mass loss compared to the CT treatment. Compared to CT, the NT treatment resulted in 30 percent less and ST yielded 7 percent more flumetralin mass in percolated water.
The GLEAMS model was used to simulate runoff, nutrient, sediment and pesticide losses from the same three tillage practices evaluated in the field experiment. The model results showed that for runoff volume, TSS, nitrogen, chlorpyrifos and flumetralin in runoff, the conventional tillage practice generated greater losses than the conservation tillage practices. Compared to the field experiment results, GLEAMS under predicted nitrogen and phosphorus in percolated water. The conservation tillage practices simulated in GLEAMS were effective in minimizing the loss of agricultural pollutants. / Master of Science
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An Assessment of Floating Treatment Wetlands for Reducing Nutrient Loads from Agricultural Runoff in Coastal VirginiaSpangler, Jonathan Travis 18 July 2017 (has links)
Floating treatment wetlands (FTWs) are an innovative best management practice that can enhance the performance of traditional retention ponds by increasing removal of the nutrients nitrogen (N) and phosphorous (P). FTWs consist of floating rafts on which wetland plants are planted, allowing the roots to be submerged below the water surface while the shoots remain above. A growing body of research has documented FTW performance with regard to urban runoff treatment, however evaluation of FTW effectiveness for treatment of agricultural runoff has received less attention. Due to high fertilization and irrigation rates, commercial nursery runoff contains much higher concentrations of N and P than runoff from urban areas. We conducted this study over two growing seasons (2015 and 2016) to assess the effectiveness of FTWs for use in commercial nursery retention ponds. In the first study we used two different nutrient concentrations, one to simulate nursery runoff (17.1 mg∙L-1 TN and 2.61 mg∙L-1 TP) and one to simulate concentrations that fall between urban and nursery runoff (5.22 mg∙L-1 TN and 0.52 mg∙L-1 TP). Four treatments were used: 1) Pontederia cordata planted in cups supported by a Beemat, 2) Juncus effusus planted in cups supported by a Beemat, 3) a Beemat with no plants, and 4) no treatment (open-water). Performance was evaluated based on a 7-day hydraulic retention time (HRT). Pontederia cordata removed between 90.3% and 92.4% of total phosphorus (TP) and 84.3% and 88.9% total nitrogen (TN), depending on initial loads. These reductions were significantly more than other treatments at both high and low nutrient loading rates. Juncus effusus performed better than the control treatments for TP removal at low nutrient concentrations, but did not perform any better than the control at higher nutrient loads. In the second study, conducted in 2016, we evaluated different plant species over two 8-week trials using simulated nursery runoff. We used five monoculture FTWs with the following species: Agrostis alba, Canna ×generalis, Carex stricta, Iris ensata, and Panicum virgatum. Additionally, two treatments were created from mixed species plantings and the final treatment consisted of an open water control mesocosm. Nutrient removal performance was evaluated over a 7-day HRT. P removal (phosphate-P) by FTW treatments ranged from 26.1% to 64.7% for trial 1 and 26.8% to 63.2% for trial 2. Trial 1 N removal (sum of ammonium-N, nitrate-N, and nitrite-N) efficiencies ranged from 38.9% to 82.4%, and trial 2 ranged from 12.9% to 59.6%. Panicum virgatum removed significantly more N and P than the control and any other FTW treatment in the second study. Both studies indicated, depending upon plant species, that FTWs can effectively remove nitrogen and phosphorous from urban and commercial nursery retention ponds. / Master of Science
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Comparative study of Web-based Services and Best Practices offered by top World University libraries and "A" grade accredited University libraries in IndiaDhamdhere, Sangeeta 29 July 2018 (has links)
In this study 64 web based services (bibliographical, patron education, patron communication and patron publication services) and best practices offered by the 70 top world university libraries and 39 top Indian University libraries were studied using different data analysis techniques like cross-tabulating for average scores and Pearson correlation coefficient and tests like Chi-Square Test and T-Test were applied to the raw data collected for final results. The library rankings as per their web-based services were correlated with their university rankings as per Webometric rankings and found that library web-based services rankings are correlating with their university rankings. Therefore, developing countries like India should improve their library web-based services rankings to improve their rankings at global level. / Doctor of Philosophy
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Extending the concept of supply chain: The effective management of value chains.Al-Mudimigh, A.S., Zairi, Mohamed, Ahmed, A.M.M. January 2004 (has links)
No / Supply chain management (SCM) is a major issue in many industries as organisations begin to appreciate the criticality of creating an integrated relationship with their suppliers and customers, as well as all other stakeholders. Managing the supply chain has become a way of improving competitiveness by reducing uncertainty and enhancing customer service. The concept of value chain management (VCM) is becoming quite prevalent in industry. Despite this popularity, there is little evidence of the development of accompanying theory in the literature. Without theory development, it is difficult to identify specific hypotheses and propositions, which can be tested, resulting in research that lacks focus and is perhaps irrelevant. This paper analyses the merits and limitations of SCM and provides broader awareness of VCM, its critical success factors and proposes a model, which covers four key elements supported by a drive on agility and speed.
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