The aim of my work is the rationalization of an elektroerosive process of sinking during the production of a die in a given firm on a sinking machine Agie Hyperspark 3HS. This machine was compared with an existing device in Kovolit Modřice, a publicly held company. And subsequently it was tried several variations of setting. Afterwards it was chosen the most optimal setting for consecutive production of concrete die.

In recreational waters, pathogen pollution is a major concern for the USEPA. The USEPA is responsible for initiating the National 303(d) List of Impaired Surface Waters. Pathogen pollution from E. coli is a common reason why recreational waters are placed on the 303(d) list. E. coli O157 H:7 and other enteric pathogens can cause serious illness and even death. Sinking Creek is a part of the Watauga River watershed which runs through Carter and Washington county. Sinking Creek is currently listed on the 303(d) as impaired due to the presence of E. coli. Because of the known presence of E. coli, it is possible that other enteric pathogens may exist in the creek. The main objective of the study was to determine the presence of E. coli and Salmonella bacteria within Sinking Creek and was accomplished by using selective media to isolate the bacteria. The second goal of the study was to understand how various temperature treatments effect the growth of Salmonella and E. coli in Sinking Creek. Water samples from Sinking Creek were incubated at 4, 28, and 37°C. The third objective of the study was to determine how the survival of Salmonella and E. coli from Sinking Creek compared to samples taken from manure slurry via a meta-evaluation. It was predicted that Salmonella would not be present in water samples taken from Sinking Creek. It was further hypothesized that E. coli and any present Salmonella would have limited to no growth at 4°C and the most growth would occur at 37°C. A pilot study was conducted to determine the growth of microorganisms naturally present in Sinking Creek. The data from the pilot study was used to determine the creek’s ability to support a healthy microbiota. Samples for the main experiment were taken from September 2019 to November 2019. The main experiment found that Salmonella was present in Sinking Creek at lower amounts than E. coli. Both E. coli and Salmonella grew significantly at 4°C. On average, the least amount of growth for Salmonella and E. coli was at 37°C. Most growth on R2A peaked at 5 days of incubation. Water incubated at 37°C showed the highest growth peaks at 5 days for all three selective plates. For all three selective plates, water incubated at 4°C peaked in growth between days 5 and 7. The results of the main experiment could have been affected by factors such as contamination. Another limitation of the study was that enumeration of the colony forming units became less accurate after larger colonies had formed. Replicating the main experiment over a longer period could indicate more representative growth curves. The meta-evaluation concluded there was no difference in decay rate between samples taken from water or manure. The results of the meta-evaluation disproved the hypothesis that manure would have lower decay rates than samples taken from water. A larger sample size is recommended to yield more representative results for the meta-evolution. Further replications of the main experiment are recommended along with studies sampling the presence of Salmonella and E. coli at various distances from the below wetlands site.

Access to good quality, pathogen-free water is a necessity for human life. Pathogencontaminated water poses a threat to human health, and steps must be taken to minimize that risk using remediation techniques, such as constructed wetlands. Sinking Creek is a tributary of the Watauga River that was placed on the 2016 303(d) list published by the Tennessee Department of Environment and Conservation due to the presence of Escherichia coli. Because of this impairment, a constructed wetland was placed in Sinking Creek to decrease the downstream transport of pathogens. Knowing this, three primary goals were made for this experiment. The first goal was to establish the seasonal presence of E. coli, Salmonella spp., and other culturable bacteria in Sinking Creek. The second goal was to determine the concentration patterns of E. coli, Salmonella, and other culturable bacteria as water in Sinking Creek flows downstream. The third goal was to use the data to analyze the effectiveness of the constructed wetland in Sinking Creek and its ability to decrease bacterial concentrations downstream. To achieve these goals, water samples were collected every Wednesday from January 29th to March 11th from four sites on Sinking Creek: two upstream from the constructed wetland and two downstream from the constructed wetland. The samples were plated on mFC, XLD, and R2A agar using the micro drop technique to establish the presence of E. coli, Salmonella, and other culturable bacteria, respectively. It was hypothesized that, because of the placement of the wetland, concentrations of E. coli, Salmonella, and other culturable bacteria would be lower at Sites 3 and 4 than at Sites 1 and 2, but this hypothesis was disproved. Data analysis and statistical tests displayed that all bacterial concentrations were higher at Sites 3 and 4 than at Sites 1 and 2. From this, it was concluded that the constructed wetland is not functioning as it was intended, and the increase in bacterial concentrations at Sites 3 and 4 suggest that there is most likely a source of fecal contamination below the wetland.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 161-168. / by Michael Archangel Semeraro, Jr. / M.S.

In this investigation the stress concentration factor was evaluated for a hollow stepped shaft with variable wall thickness and two fillet sizes. Electric strain gages of the SR-4 type were employed to measure strains in the fillet section. Values of the stress concentration factor were determined with the ratio of inside to outside diameter ranging from 0.25 to 0.625. A decreasing relation was established between stress concentration and the internal diameter. A satisfactory method of positioning gages accurately on the complex fillet surface was developed. This method featured an intermediate steel template with positive referencing. / M.S.

In the United States, karst ecosystems cover approximately 20 percent of the country and karst aquifers provide 40 percent of the water used for drinking. In karst-influenced watersheds, karst features such as sinkholes and sinking streams act as rapid pathways for carrying water and pollutants into streams and groundwater. Human activities on karst landscapes can present some special problems such as alterations to hydrologic regime, contamination of groundwater, ground subsidence, and damage to cave ecosystems. Modeling a karst-influenced watershed can provide a better understanding of the interactions between surface and ground water and how water quality is affected by human activities. Several models were evaluated to determine their ability to model both discharge and nutrient transport in karst watersheds. The Soil Water Assessment Tool (SWAT) model was found to be appropriate due to its capability to represent almost all of the hydrological processes, its user-friendliness, and its ability to generate most of the parameters from available data. Moreover, SWAT can represent nitrogen transformations and transport processes and calculate nitrogen loadings, which is critical for karst watersheds. While it has been widely used and found to be an appropriate prediction tool, it does not explicitly include the capacity to represent specific features characteristic of karst-influenced basins. Baffaut and Benson (2008) modified the SWAT 2005 code to simulate faster aquifer recharge in karst environments, and this version was further modified here in the SWAT-Karst to represent karst environments at the HRU scale. A new parameter sink allows simulating the hydrology and nitrate transport in a sinkhole representing its unique landuse and soil characteristics, and a new parameter ss partitions nitrate transported with water that is lost from sinking streams. The SWAT-KARST model was used to simulate discharge and nitrogen loadings within the Opequon Creek karst-influenced watershed, located in the Potomac and Shenandoah River basin in Virginia and West Virginia. In the Opequon Creek watershed, SWAT-karst using the HRU to represent sinkholes had a more notable impact in the watershed hydrology than SWAT-B&B using a pond to represent sinkholes. Results of statistical evaluation show that SWAT-karst and the Baffaut and Benson (2008) version performed better than SWAT in predicting streamflow in a karst-influenced watershed. Although SWAT-karst showed almost the same performance as SWAT-B&B, SWAT-karst model offers the flexibility to represent the unique relationship between surface and ground water in karst features in an HRU. Using an HRU to represent sinkholes can depict the associated variability of a karst landscape. The new variables sink and ss provide a mechanism to represent the nutrient transport through sinkholes and sinking streams. Sensitivity analysis showed that SWAT-karst was sensitive to the new parameter sink which can be used for model calibration and to represent water recharge and nutrient transport to aquifers outside the watershed boundary. / Master of Science

Investigating linkages between the compositions of suspended (seston) and benthic particulate matter is important to the understanding of organic matter (OM) cycling and nutrient retention in aquatic systems. We compared the quantity and quality of the truly suspended (TS) and settleable (SB) fractions of seston as well as benthic particulate matter in the tidal freshwater James River, Virginia. The mass of seston and OM was consistently higher in the TS fraction compared to the SB fraction. OM was preferentially retained in the TS fraction relative to seston. The proportional contribution of OM constituents (chlorophyll a, particulate organic carbon and nitrogen) to the two fractions was consistent across observed concentrations whereas increases in seston concentration resulted in decreased proportions in the TS fraction. Benthic constituent reservoirs were large relative to the SB fraction but the higher proportion of OM in the SB fraction suggests that the settleable material was more labile.

by Matthew Bailey Greenberg, Ng Hin Wah. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 61-62). / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Chapter II. --- CONVERTIBLE BONDS AND WARRANTS --- p.3 / ConvertIBle Bonds --- p.3 / Value At Maturity --- p.5 / Value Before Maturity --- p.6 / Warrants --- p.8 / The Difference Between Convertible Bonds and Warrants --- p.11 / Considerations of Issuing Convertibles and Bond with Warrants --- p.13 / Valuation of Convertible Bond --- p.15 / Valuation of Warrants --- p.18 / Chapter III. --- CALLABLE BONDS --- p.20 / Performance Characteristics of Callable Bonds --- p.21 / Valuation of a Two-year Callable Bond with the Salomon Brothers Model --- p.22 / Valuation of a Three-year Callable Bond with the Salomon Brothers Model --- p.25 / Step1: Determination of ru and rd --- p.27 / "Step 2: Determination of ruu, rud and rdd " --- p.28 / "Black, Derman & Toy Model (BDT) " --- p.30 / Step 1: Determination of ru and rd --- p.31 / "Step 2: Determination of ruu, rud and rdd " --- p.32 / Chapter IV. --- SINKING-FUND BONDS --- p.37 / Advantages for the Investor --- p.38 / Disadvantages for the Investor --- p.38 / Methods Used by Issuers for Early Bond Redemption --- p.39 / Valuation of Non-callable Sinking Fund Bonds --- p.40 / Valuation of Callable Sinking Fund Bond --- p.45 / Chapter V. --- VALUATION OF A CALLABLE BOND BY A COMPUTERIZED PROGRAM… --- p.47 / System requirements --- p.48 / Opening the program file --- p.48 / Manual for using the program --- p.48 / Construction of Interest Rate Tree --- p.48 / Valuation of a Callable Bond --- p.50 / APPENDIX --- p.55 / BIBLIOGRAPHY --- p.61

Since the passage of the Clean Water Act, concern about surface water quality has increased. Reducing exposure to pathogens and adverse impacts on human health because of contact with surface waters has become the focus of many regulatory agencies. Fecal pollution is often a cause of surface water impairment. Fecal indicators, such as fecal coliforms and Escherichia coli, are used as surrogates to evaluate the presence or absence of fecal pollution. However, a growing body of research has shown that these species lack key characteristics necessary to be adequate indicators. As such, explorations into the efficacy of indicator species in predicting fecal pollution in water are necessary. Sinking Creek is a tributary of the Watauga River Watershed, located in Northeast Tennessee. Approximately ten miles of Sinking Creek have been placed on the national 303(d) list for fecal pollution, denoting the presence of fecal contamination exceeding the regulatory limit. Salmonella and Aeromonas are two enteric pathogens that would be expected to be detected in fecally contaminated waters. The primary objective of this study was to detect the presence of Salmonella and Aeromonas in Sinking Creek. The secondary objective was to evaluate their relationship with fecal coliforms, E. coli, and water quality parameters. Six study sites along Sinking Creek were sampled and standard methods were used to enumerate Salmonella and Aeromonas. Samples for Salmonella were collected for 8 months, while samples for Aeromonas were collected for seven. Salmonella and Aeromonas were present in Sinking Creek. Salmonella had the highest concentration at site 2 (the most downstream site), and was detected during all months of the study except for November. Salmonella concentrations varied by site. Aeromonas was present only during colder months, and had the highest concentration at site 2. Both Salmonella and Aeromonas show qualitative relationships with water quality parameters, such as dissolved oxygen and conductivity. However, statistically significant correlations of Salmonella and Aeromonas with water quality parameters were not observed. The lack of statistical significance is partially due to large variability and a small data set. Neither Salmonella or Aeromonas exhibited a relationship with fecal coliforms or E. coli. Therefore, fecal coliforms and E. coli may not be adequate indicator species for the presence of Salmonella, Aeromonas and possibly other waterborne pathogens. Traditional indicator species may inflate risk of pathogen exposure. Thus, many water bodies may be unnecessarily deemed as impaired. The results from this study can be used to guide further research regarding covariates influencing pathogen densities at fecally contaminated sites, as well as to guide decisions regarding impaired surface waters and management techniques.

The purpose of this research is to understand the sinking particle dynamics in the Gaoping Submarine Canyon (GPSC), the change of their geochemical character, and their causal relationship with dynamic parameters. Also this research inquires into the significance of sedimentary environment, transport process, and the influence of non-tidal actions (turbidity current) in the sedimentary environment. The field experiments including LADCP moorings, T6KP(1/10/-3/20), and T7KP (7/7-9/11) sediment traps moorings were deployed in the GPSC to collect the time-series data of sinking particle and related dynamic parameters. Parameters of discrete sediment analysis were used to build continuous time-series data by interpolation, and time series analysis applied to understand the change of physical and geochemical character and their correlation with dynamic parameters. The results showed that sinking particles of different grain-size classes confront different forces in the canyon and their grain-size distribution structures are influenced accordingly. Vertical component of the flow has more influences on coarse particles, while the along canyon flow component has more influences on fine particles. The influence of semidiurnal tide on sinking particle is not clearly resoloved, but spring tide and neap tide affect them significantly. GPSC is normally a stable deposition environment dominated by tidal currents. Particle-reactive materials vary upon with clay concentration, coarse paericles vary upon with the flow field, and the change of benthic nepheloid layer thickness during spring and neap tide cycle affects the vertical distribution of particle size-groups near the bottom of canyon. The particle in the upper (rim) and lower (near the bottom) canyon belong to different transport and dynamic regimes. The upper part was affected by upwelling and shelf processes, while the lower part was affected by tidal currents. In case of episodic event, if surge-like turbidity flows pass near the canyon floor, in the waxing phase, the sinking particle would be affected by the strong momentum of resuspension and mixing which leads to a dramatic change of geochemical character of these particles. In turbidity current event, coarse sand and silt are the major particle sizes with low clay content, suspended sediment concentration about 4.41 g / l. The fluctuation of time series analysis by HHT found a frequency between 2.1~9.8 clcle per day. In the waning phase, dynamics and geochemical character of sinking particle will gradually return to those variations in tidal dominance. In winter, most sinking particles in GPSC are the source material (particles of biological origin) coming from the off-sea with the upcanyon flow during spring tide period. In summer, most sinking particles in GPSC are the terrigenous material (higher organic matter) output from the Gaoping River during typhoons, and flowing to the South China Sea along the canyon with turbidity flow.