Nonpoint source pollution from agricultural activities significantly impacts quality of receiving water bodies, including increases in stream sediments and nutrients, and occurrence of pesticides in both surface and ground water. Agricultural activities in the West Wellfield Interim Protection Area (WWIPA), located in West Dade County in South Florida, have potential to impact both the environmentally sensitive Everglades and Florida Bay, and the Biscayne aquifer. The Hydrological Simulation Program-Fortran (HSPF) has been used to simulate water and constituent transport in the WWIPA and to determine possible impacts. Surface runoff, groundwater recharge, and transport of sediments, nutrients and pesticides are simulated by this model. ARC/INFO Geographic Information Systems (GIS) is interfaced with HSPF to store, manage, and display data, and derive input parameters for the model. Results of HSPF simulations are also visually presented through GIS. A GIS user interface was developed for the study area. Menus were created through which the database can be queried to derive model parameters and to visually present results through maps. Model results show that sediments, nutrients and pesticides are present in surface runoff, and nutrients enter the ground water. Various model test runs were made to minimize pollution levels without hindering agricultural production. They include application of minimum required rates of fertilizers, replacement of fertilizers by sewage sludge, and the effect of future urbanization.

Adsorption experiments using both monosodium methanearsonate (MSMA) and its inorganic degradation by-product species As(+5), as sodium arsenate Na2AsO4, were conducted to evaluate the sorptivity of these constituents to various fractions of soil samples taken from the West Palm Beach Country Club. Adsorption data were analyzed with common isotherm equations (i.e., Linear, Freundlich, Langmuir) to determine Kd for each arsenic (As) species/soil fraction. Simulations using a one-dimensional pesticide transport model, PRZM 2.0, were completed to evaluate possible dissolved concentrations of arsenic at the water table interface under 8 different application scenarios for the soil profile found at the sample site. All contaminant/soil systems displayed a linear sorptivity relationship (R2 ranging from 0.8262 to 0.9779) with Kd values (units of L/g) ranging from 0.0102 to 0.2295. Results also indicate As(+5) had a higher affinity for the soil fractions than MSMA. PRZM-2.0 predicted concentrations of dissolved arsenic at the water table interface from 0.04 to 1018 ppb within 1 month from only 1 application. Florida's MCL for dissolved as in groundwaters is 50 ppb. It is recommended that the registration and use of MSMA be re-evaluated as it may impact ground water quality at golf courses or other sandy aquifer systems.

The introduction of aquatic nuisance species (ANS) and bacterial pathogens from discharge of ballast water by sea-faring vessels is an ongoing problem that threatens ecosystems and human health. This study investigates the disinfecting capability of ferrate in a marine environment on several organisms listed in international standards for ballast water management. Organisms were grown in a saline solution and were treated with dosages of ferrate ranging from 0.25-5.0 mg/l. A ferrate dose of 5 mg/l resulted in almost complete kill for all organisms tested. Smaller dosages have also been very effective, particularly if all organic material from the nutrient broth used to cultivate them is removed by washing the cells with saline solution. Ferrate appears to act very quickly, with tailing occurring after about 5-15 minutes. Analyses of the data with the CT approach, the Chick-Watson and Hom's models, and an oxidant demand equation derived from equations recommended by the Water Environment Federation (WEF) are in good agreement that ferrate concentration is more important than contact time. The Hom's model appeared to most accurately represent the action of ferrate on these organisms. Salinity and pH did not adversely affect results, and regrowth was not a problem. Two measures to reduce clumping did not eliminate the observed tailing effect, suggesting a different mechanism for this phenomena. These preliminary tests indicate that ferrate could be a very effective disinfectant in the treatment of ballast water, and the short half-life of ferrate is an advantage, since the ballast water is subsequently released into the environment.

<p>Provisions for the design of masonry walls is subject to uniformly distributed pressure normal to the surface of the wall differ significantly from country to country. These differences may be attributed both to differences in design philosophy and to a general lack of conclusive or widely accepted experimental and analytical research. Most of the previous research in this area was concerned with brick masonry and with practical rather than well defined support conditions. Also, the available design methods were not accurate or rational. Therefore, this study was initiated to investigate the flexural behaviour of hollow concrete block masonry both experimentally and analytically and to assess the design methods for laterally loaded walls.</p> <p>The experimental program included 30 full scale wall tests representing different support conditions and aspect ratios. In addition, stack bonded prisms and wallettes were used to determine the flexural tensile strengths. The full scale tests were performed using a test facility designed to accommodate tests of masonry panels up to 6.0 m long by 3.6 m high and to provide well defined support conditions. The observed behaviours of the walls were compared to other walls of the same series and to other tests to investigate the effects of variability, aspect ratio, support conditions, and the presence of either precompression along the top panel or precracking near the panel center.</p> <p>A nonlinear finite element model capable of reproducing the observed behaviour of the walls was developed and used to extend the knowledge of masonry wall behaviour to include untested conditions and configurations. In this model, the anisotropic nature of the masonry, the nonlinearity due to cracking, and the effects of the transverse shear were taken into considerations. Also, the existing biaxial failure criteria were examined and proposed macroscopic biaxial failure criterion was incorporated in the finite element model to predict the strengths and the failure modes for masonry assemblages. This criterion accounted for the anisotropic and composite nature of masonry and was based on physical interpretations rather than being strictly a phenomenological criterion.</p> <p>Finally, the available design methods were compared using the extended data from the analytical model and design a method based on elastic plate theory was proposed. This method was rationally developed to predict first cracking and failure capacities for masonry panels simply supported on three or four sides for a wide range of aspect ratios.</p> / Doctor of Philosophy (PhD)

The oxidation kinetics of m-substituted phenols by TiO2/UV were investigated. An attempt was made to correlate Swain-Lupton parameters (R) for aromatic substituents with the oxidation kinetic constants, based upon molecular structure and reactivity theory. Irradiation experiments were carried out with suspended aqueous TiO 2 powder and substrate mixture in a Rayonet Photochemical Reactor. Langmuir-Hinshelwood model was applied to obtain apparent kinetic rate constants. A linear correlation is observed between Langmuir-Hinshelwood kinetic parameters and Hammett constants for m-chloro, m-bromo and m-fluoro phenols. The changes in p values of Hammett plots at pH 3 suggest that the main degradation pathway may involve a positively charged intermediate, such as a radical cation formed by direct electron transfer to the positive holes at low pH. At high pH levels, however, substrate speciation, surface charge of the semiconductor, and bandgap shift appear to lead to a change in the degradation mechanism.

Surface coating and drying operations typically exhaust large air volumes containing low concentrations of volatile organic compounds (VOC) with potential adverse environmental impacts. Operating on the principle of catalytic incineration, the SUNKISS Thermoreactor produces infra-red heat for paint drying and curing. Reported benefits include reduced drying time, improved surface coating finish, smaller exhaust air/solvent volumes. and greater energy and economic efficiency. In addition. the SUNKISS Thermoreactor has been reported to reduce VOC emissions due to oxidation of the solvent vapors. This claim was investigated under laboratory conditions at the University of Central Florida (UCF). Primary system components developed as a part of this study included the VOC-in-air flow system, a completely mixed test chamber, and a sampling train which resulted in the generation of data exhibiting a high degree of precision. Design and calibration studies necessary to maintain that accuracy and precision constituted major components of the work performed. Our study showed that an 18 to 48 percent reduction in VOC emissions may be expected from the SUNKISS Thermoreactor. VOC destruction was found to be a function of detention time within the test chamber and not inlet concentrations. Very little difference was observed during experimental runs involving both Hexane and Methyl Ethyl Ketone. Relationships among destruction efficiency, air flow rate, the generation of carbon monoxide and incomplete combustion of the a uxiliary fuel supply were also determined.

This research addresses emissions of hexavalent chromium mist from hard chromium electroplating operations. Most of these emissions are typically captured by a ventilation stack and directed to a pollution control device; those which escape capture are called fugitive emissions. Releases of toxic materials such as hexavalent chromium must be reported annually to the Environmental Protection Agency (EPA) under provisions of the Superfund Amendments and Reauthorization Act (SARA) Title III of 1986 via the Toxic Release Inventory (TRI), Form R. The objectives were: (1) to provide estimates of fugitive hexavalent chromium emissions for the completion of Form R; and (2) to develop a predictive model for stack and fugitive emissions versus process and ventilation parameters. The database for stack emissions included published results from EPA studies. Fugitive release data were generated by field characterization at two operating facilities. Supplemental data for stack releases were also obtained during this field activity. The fugitive releases were documented to represent a small portion of the total atmospheric discharge; in most instances, the fugitive releases were less than the detection capability of the sampling/analytical protocols. Stack releases were successfully correlated with a measure of production activity (ampere-hours), production capacity (mass of chromium in the process bath), tank dimensions (plating bath surface area), and ventilation efficiency (ventilation slot area). This effort was supported by the EPA in the form of a cooperative agreement with the American Electroplaters and Surface Finishers Society (AESF).

This study investigated microfiltration of Lake Michigan Water for the production of drinking water. A 60 gpm Memcor microfiltration pilot plant was operated for nine months at Manitowoc, Wisconsin to determine and model the performance characteristics of a microfiltration pilot plant for varying surface water conditions. Statistical regression and modeling was used to determine and develop quantitative relationships between time of operation and several operational variables for water quality and productivity. Modifications of Darcy's Law and flux decline data were used to develop a model relating temperature and flux to cleaning frequency. Statistical hypothesis testing and associated modeling were used to determine if relationships existed between the water quality and the independent operating variables affecting microfiltration. The study demonstrated that the filtered water turbidity or particle count did not carry with the flux or the influent water temperature and that the degree of turbidity or particle count removal was dependent on the raw water turbidity or particle count. Direct filtration of an alum pretreated feed water was found to greatly increase time of operation between cleanings for temperatures below 48 degrees F. As expected the size exclusion membrane process was found to have no effect on dissolved of diffusion controlled solute rejection. the investigation found the turbidity and particle counts of the microfiltered water was less than the same for the finished water produced by the conventional alum coagulation, sedimentation and filtration process. The investigation demonstrated that microfiltration could be used to consistently produce a drinking water that met or exceeded state or federal requirements at Manitowoc. Based on the results of this investigation, a recommendation was made to use microfiltration as the treatment process of choice for the treatment of Lake Michigan Water.

The objectives of this research were to quantify formaldehyde consumption due to plating and parasitic reactions and determine the magnitude and distribution of formaldehyde losses from the electroless copper plating process. Plating and rinse bath samples obtained from three electroless copper plating operations were analyzed for formaldehyde and copper in order to develop a mass balance analysis about the plating bath for periods of active production and no production. Fugitive air and stack releases of formaldehyde were estimated using emission factors developed from air sampling at the three facilities. It was determined that approximately 90% of the formaldehyde added to the plating process was consumed by some type of chemical reaction. The remaining 10% of formaldehyde represents losses from the plating operation. For the facilities with a waste plating solution stream, atmospheric losses accounted for approximately 25% of the total losses. The mass of fugitive air formaldehyde measured approximately 2.8 times that escaping through the stack. Dragout accounted for approximately 2.3% of the losses with the remaining going to the waste stream. For the facility without a plating solution waste stream, formaldehyde losses were distributed 59% to atmospheric releases and 41% to the rinse tank. Fugitive and stack releases were approximately the same at 29% of the formaldehyde losses. Formaldehyde consumption due to parasitic reactions for periods of active plating and no plating were determined for two facilities. The rate of parasitic consumption during periods of production was found to be approximately 3 times greater than that for no production. The rate of parasitic consumption was observed to increase with increasing bath temperature.

Described is the design specification for an Artificial Neural Network (ANN) communication controller. The communication controller will provide efficient data exchange between individual ANN units in a large parallel system. Interconnections are dynamic in nature, and can be configured to implement any arbitrary feedback path. A nexus topology is used to interconnect the communication controllers in a system. Because the recursive nature of the communication protocol, the communication controllers function identically regardless of position in the hierarchy, providing scalability and simplifying VLSI design. The protocol and the communication controller's modes of operation are presented in detail.