Groundwater on the eastern coast of the State of Virginia exceeds the Environmental Protection Agency Maximum Contaminate Level (MCL) for fluoride. This thesis explores the use of alum and alum and lime for the reduction of fluoride to the MCL or lower. In order to reduce an initial fluoride concentration of 2.1 mg/l to 1.8 mg/l 125 mg/l alum was required, for reduction from 5.5 mg/l to 1.8 mg/l, 415 mg/l alum was needed, and for reduction from 8.0 mg/l to 1.8 mg/l, 670 mg/l alum was utilized. If the system pH was lowered below 6.0 the fluoride reduction was insufficient and thus lime was required to maintain the pH above 6.0. However, hardness increased with the lime dose and other methods of pH adjustment such as employing soda ash should be considered. Aluminum was detected in the unfiltered treated water, perhaps in sufficient concentrations to cause problems in the distribution system, but further testing of filtered samples is needed. Sulfates were low in the raw water, but buildup with the addition of alum. No tests were made for sulfates in the treated water. Tests of the sludge produced by the addition of alum and lime indicated high volumes, low solids and very poor dewatering characteristics. Polymers should be considered as a possible means to achieve better sludge dewatering. / Master of Science

"Architecture As A Three-Dimensional Language" is defined as a communication between architect and man manifested in form. It is useful to make an analogy between architecture and language since the purpose of both is to communicate. Communication requires the use of signs and symbols. In architecture form communicates meanings through signs and symbols. Some meanings communicated in architecture through signs and symbols demonstrate a sense of shelter, function, and movement. Function manifested in form anticipates the need for movement in the environment. Movement involves defining a direction. Direction can be established through the use of view and path as they relate to form. These elements create the approach, entrance, and circulation pattern of each building. As each individual building communicates movement by establishing a direction, the city also establishes a direction for movement in a universal way. Describing architecture as a language whose basic mode of communication is form suggests a design criteria based on how man perceives and responds to what the architect's design is trying to communicate. / Master of Architecture

The break-in behaviors of two similar heterogeneously catalyzed systems were studied during propylene disproportionation. A cobalt oxide-molybdena-alumina (CoO-MoO₃—Al₂O₃) catalyst was found to undergo a rapid increase in the catalytic activity during the first 100 seconds of contacting with the reactants and this was the order of magnitude of the mass transport delays. A slower first order process was observed with a break-in period of about 30 minutes, and this process is reversed by inert purge. The effects of the products of propylene disproportionation on the activity of a tungsten oxide on silica (WO₃-SiO₂) catalyst were studied by using a split-bed reactor and using mixtures containing low concentrations of products in propylene as feed. In both experiments the products were found to have some suppressing effects on the activity of this catalyst. The activity of the WO₃-SiO₂ catalyst was reduced to one tenth of the original by adding 0.02N NaOH aqueous solution to the catalyst and drying at 120°C for twelve hours. Dosing hydrogen (a reductant) and oxygen (an oxidant) to the fully activated WO₃-SiO₂ catalyst individually or alternatively reduced the activity of this catalyst to a point where another break-in period was needed to restore full activity. The break-in period of cooling and reheating the steady-state WO₃-SiO₂ catalyst in stagnant propylene was much shorter than that observed in propylene flow. / Master of Science

One of the major problems in image processing is information reduction. The research reported in this thesis examines the semantics of cortext-independent edges in a real-world environment. Topics discussed include a classification scheme for edges, edge semantics, and a method for minimizing noise effects in edge computations. / Master of Science

The criteria for design and construction of a single family dwelling in a tropical oceanside environment will be investigated. Tropical vernacular architecture will be studied. Concepts established will be integrated in a modern architectural language, preserving the time tested truths of the local architecture. The position of tropical vernacular architecture and contraposition of modern architecture will then be synthesized into a single family tropical dwelling based on established criteria. / Master of Architecture

Urban runoff samples collected from a parking lot in Blacksburg, Virginia were analyzed by several techniques for fecal coliform recovery. The samples were also analyzed for heavy metal concentrations. Statistical analyses of data by the paired-t test showed that the standard membrane filter technique (MF) yielded significantly lower recoveries (0. 05 level) than the standard MPN procedure. A modified membrane filter technique employing a two-layer agar and a two hour 35°C preincubation period (M-2hr) was found to yield recoveries consistently greater (0.01 level) than the standard MF technique. Increasing the preincubation period to five hours in this modified method (M-5hr) resulted in recoveries that were even greater (0.005 level). The recoveries of the M-5hr method were found to closely approximate the MPN recoveries in most cases. It was concluded that a substantial percentage of the fecal coliform population found in urban runoff may be injured by a host of environmental factors, though no correlations could be made with metal concentrations or elapsed time between rainfalls. The M-5hr method was concluded to be quite useful in the recovery of these stressed organisms. though growth of non-fecal-coliforms was increased and made enumeration of the fecal coliforms more difficult. / Master of Science

In 1708 Colonial poet Ebenezer Cooke published a satirical poem entitled The Sot-Weed Factor. The poem, written in the style of Samuel Butler's Hudibras, tells of a tobacco merchant's first visit to Maryland. In 1960 contemporary novelist John Barth wrote a novel, also entitled The Sot-Weed Factor and used Cooke's life and poem as sources. In order to understand why Barth chose these eighteenth-century sources for his twentieth-century novel, one must first examine his theory of "literature of exhaustion." According to Barth, this literature begins with the realization that the novel is dead or dying and uses this fact as a theme. The writers of this fiction must be aware of the history of the novel and must write technically up-to-date novels, but they must, at the same time, treat matters of the human heart. One way to accomplish these goals is to imitate earlier works, as Barth does in The Sot-Weed Factor. Because the novel imitates a two-hundred- fifty-year-old poem, it acknowledges that the history of literature does not begin with itself. Yet Barth's imitation parodies his model by embellishing and exaggerating it to a point of absurdity. The novel thereby reflects this same absurdity in the modern world and thus reaches the hearts of those who must live in it. Thus, though Barth imitates an eighteenth-century poem, he creates a thoroughly modern novel that meets his requirements for literature of exhaustion and gives new life to a moribund genre. / Master of Arts

This paper is concerned with the linear elastic static analysis of thin arbitrary shell structures by the use of the displacement approach finite element method. The various factors involved in selecting a shell finite element are discussed. A comprehensive formulation of a 27 degree of freedom, arbitrary, doubly-curved, nonconforming, triangular, shallow shell element is presented. Both the normal and tangential displacement fields are expressed by "incomplete" cubic, natural coordinate, polynomial interpolation functions. A WATFIV/FORTRAN computer code utilizing this element in a linear elastic static analysis of thin shell structures is formulated and presented. Demonstration problems are presented and comparisons are made with solutions in the literature. / Master of Science

Mass transit bus systems can be characterized by two aspects, supply and demand. As in most systems, the supplier's objective is to minimize the system's total cost yet maximize its attractiveness to the users. The present study applied this concept to a bus system in small urban area by minimizing the total operational costs and maximizing the system's attractiveness to the riders. The total operational costs are reduced by designing a route-network which will yield a minimum total bus travel distance within the physical and economic constraints. On the demand side, a measure of attractiveness is constructed based on the probability that a person will ride a bus given a certain level of service of the bus system and a cost figure for using the private automobile. The main purpose of this work is to find the equilibrium point of the demand and supply of a bus transit system so that decisions on some policy variables such as bus capacity, bus fare, determined. / Master of Science

A study was undertaken to determine the problems involved in applying wind-produced electric energy toward the needs of an apple storage facility, and to design an appropriate energy system. Fruit requirements, wind generator characteristics, and energy storage are discussed. Detail design of a cooling system was performed, including design calculations and equipment specification. The expecting cooling loads for the building were calculated and a vapor-compression refrigeration condensing unit was selected. An energy storage device utilizing the latent heat of fusion of ice was designed and calculations were performed to determine its energy capacity and heat transfer characteristics. The requirements of the air distribution system are discussed, and the pressure drop calculations are shown in connection with the circulating fan selection. The overall system operation is discussed, including control system requirements. / Master of Science