A laboratory study was conducted to compare the coliform recovery capabilities of two membrane filter techniques on coliforms exposed to varying chlorine residuals and contact times. An enrichment-step membrane-filter method (E-MF) involved the incubation of a filtered water sample on lauryl tryptose plus 1.5 per cent agar for two hours at 35°C prior to transfer of the filter to LES-Endo agar and a final incubation for 22 hours at 35°C. A single incubation of the membrane filter for 24 hours at 35°C was employed in a non-enrichment membrane filter method (NE-MF). A free chlorine residual was established in a synthetic test water at a neutral pH and constant temperature prior to inoculation of the water from a suspension of bacteria comprised of four coliform genera commonly found in natural waters. Timed samples from 5 seconds to 15 minutes, analyzed for coliform recovery by the E-MF and NE-MF methods revealed an average increase in recovery of the E-MF to NE-MF method of 1.6:1. When the initial inoculum was kept below 1 x 10⁴ cells/100 ml, and the test water was chlorine demand- free no coliforms were recovered by either method after two minutes of contact time with free chlorine residuals greater than 0.12 mg/l. Many of the recovered colonies failed to produce a characteristic sheen but were verified as coliforms. It was concluded that all coliforms were effectively killed at chlorine contact times greater than two minutes and free chlorine residuals greater than 0.13 mg/l, in chlorine demand-free water. Free chlorine residuals of 1.0 mg/l effectively killed all coliforms within five seconds. / Master of Science

Two series of trials were conducted for five weeks to compare the performance of three to four week weaned pigs reared in single, double and triple deck pens. In these trials, the addition to a starter diet of a flavor compound previously fed in the lactation diet was evaluated as a means of stimulating postweaning performance. In the first series, two trials were conducted using 128 pigs each from sows fed flavor and non-flavor lactation diets. Pigs were reared in single, bottom and top deck pens. All pigs were fed flavor starter diets ad libitum. The combined data showed no significant differences in average daily gain, feed consumption and feed per gain between pigs reared in the various decks. Also performance was similar for pigs from the two sow groups. In the second series, three trials were conducted using 48 pigs each from sows fed flavor and non-flavor lactation diets. Half of the pigs from each of the sow groups was fed flavor starter diet and half was fed non-flavor starter diet. Pigs were reared on bottom, middle and top decks of a triple deck system. The combined data revealed no significant differences between pigs reared on the various decks. Also performance was similar for pigs fed flavor and non-flavor diets regardless of whether pigs were from sows fed flavor or non-flavor diets. In this study the double and triple deck systems increased nursery densities by 67 and 200%, respectively. The.use of the flavor compound in the sow lactation and pig starter diet did not improve performance. / Master of Science

Bird utilization of twenty fields was observed at monthly intervals for one year, from May 1977 to April 1978. The 20 fields were located in 2 areas of southeastern Virginia. A total of 30 bird species were observed using the fields. The migratory and movement patterns of some of the species were determined from bird banding data. A small proportion of 6 species recovered in the study area were originally banded to the south of the study area. Fecal material, soil from feet and crop contents were taken from several bird species collected in the field and analysed for Cylindrocladium crotalariae. Soil samples from a blackbird roost in the area were also analysed for C. crotalariae. None of the samples taken showed presence of the fungus. Microsclerotia of the fungus were force fed by different methods to 3 species of captive bird (Canada Geese, Japanese Quail, Bobwhite Quail) to determine viability after passage through the gastrointestinal tract. No viable microsclerotia were detected in fecal material taken from birds force fed loose microsclerotia. A very small number (a total of 5 of 10,000 microsclerotia from 2 geese) proved to be viable after passage through Canadian Geese after being force fed microsclerotia in porous bags. / Master of Science

A computerized data-analysis and information system, VADMIS (Virginia Deer Management Information System), was developed to summarize and analyze Virginia county, district, region, and state deer harvest data. Published wildlife literature and state wildlife agency progress reports were reviewed to identify and evaluate potential methods of analyzing and presenting deer harvest data. Meetings and correspondence with Virginia Commission of Game and Inland Fisheries biologists provided significant information regarding current data analysis techniques and information needs of the Game Commission. Data analysis methodologies and computer programs developed during prior graduate research studies at VPI&SU were also reviewed. An auto-regression system was developed to predict county deer harvests for three season types; bucks-only, either-sex at the beginning or end of a bucks-only season; and either-sex hunting all season. The average accuracy of 1,076 county predictions made between 1962 and 1976, inclusive, was 74.6 percent. The VADMIS system also summarizes changes in recent county, district, region, and state harvests; produces histograms to illustrate county, district, and state harvest trends; summarizes changes in county season regulations and the associated changes in county deer harvests; summarizes harvest data collected at 15 check stations west of the Blue Ridge mountains; determines optimum deer management regions; and produces contour computer maps to illustrate and identify state-wide harvest trends. The VADMIS system was designed to facilitate ease of operation, maintenance (data update), and future improvements, modifications, and extensions. Although the VADMIS system was developed for Virginia, in particular, it may be modified for use by other states. / Master of Science

Arrowarum [Peltandra virginica (L.) Schott and Endl.], waterhyacinth (Eichhornia crassipes (Mart.) Solms], American bulrush [Scirpus americanus (Pers.)], and smooth cordgrass [Spartina alterniflora (Loisel.)] removed Kepone® (dechachloro-octahydro-1,3,4-metheno-2H-cyclobuta[cd] pentelen-2-one) from water. ¹⁴C-Kepone was translocated from roots and accumulated in small, but significant, quantities in the aerial portions of the plants. Approximately 80% of the ¹⁴C-Kepone was removed from solution within three days by arrowarum, and waterhyacinth, however, very little additional Kepone was accumulated by these species after the initial three day exposure. Kepone uptake by the roots of American bulrush and smooth cordgrass appeared to continue for a seven day period. Translocation to the aerial portions of the plants was slow, with significant quantities reaching the shoot after seven days. Additional ¹⁴C-labelled compounds were detected in shoot and root extracts, indicating possible metabolism of the Kepone molecule by these plants. / Master of Science

A committee of the Group for the Advancement of Psychiatry (GAP) surveyed family therapists in 1966. Those respondents consisted mostly of psychiatrists, psychologists, and social workers. Since that time, the number of therapists from other affiliations has increased. Those professionals had not previously been surveyed as to their theories and practices. A sample of 102 American Association of Marriage and Family Counselors (AAMFC) included clergy, educators, marriage and family counselors, pastoral counselors, and psychiatric nurses as well as psychiatrists, psychologists and social workers. The AAMFC members were in agreement as to the theorists who were the most influential in their field, Satir having been the first choice. Although the AAMFC therapists practice an average of only eight hours of family therapy per week, usually in combination with other therapies, they are fairly committed to it as a treatment modality, even to the point of considering it for their own families if an individual member were in distress. Many connected family therapy with problems appearing in children or adolescents and many saw all therapy as family therapy. The respondents were flexible in relation to the number of people seen in and apart from family sessions, in relation to duration of treatment, and in relation to the idea that family therapy can be contraindicated in some cases·. The majority agreed that the interest of the family as a whole is of primary concern to the family therapist. It was recommended by the GAP researchers and the current researcher that a theory of family therapy be developed integrating family and psychodynamic theories, that a definition for family therapy be formulated, and that continued clinical research be done in the area of family therapy. / Master of Science

The primary purpose of this thesis is to investigate stability boundaries, or load interaction curves, of a reticulated dome. An elastic, geometrically nonlinear model with 21 degrees of freedom is considered. The nonlinear response of the model to imposed loads is determined using two separate computer programs as a check on each other. One program is based on the static perturbation technique and the other is based on an energy minimization technique. Program.solutions are compared with each other and with other published solutions. Various characteristics of the two programs are discussed. Five stability boundaries for two independent loads and one for three independent loads are presented. These stability boundaries are all found to exhibit convexity or piecewise convexity toward the origin. Characteristics of points composing the stability boundaries are noted and discussed with emphasis placed on ways that point characteristics affect boundary shape. Three observations are noted: 1. Critical points classified as limit points consistently form smooth boundaries, those classified as bifurcation points do not. 2. It is possible to predict the occurrence of a cusp in the stability boundary in certain load planes. 3. The occurrence of load maxima at cusps in stability boundaries is due to the higher degree of balance achieved in the stress distribution throughout the structure at that critical point. In addition, a method of estimating lower bounds and a theorem dealing with convexity of stability boundaries are briefly discussed. / Master of Science

The service life of furnace refractories could be enhanced by coating them with a thin, dense layer of refractory material which can resist adverse furnace environments. The objective of the present research was to obtain a pure coating of silica, (SiO₂), on the surface of alurnino-silicate refractory bricks. A chemical vapor deposition process utilizing the oxidation of (A) SiCl₄ and (B) SiH₄ was used as a basis of obtaining such a coating. Surface morphology examination, by scanning electron microscopy, of the as-deposited and post fired deposits, showed that firing had the effect of coalescence of the individual spherical particles leading to densification. Slag corrosion tests of the uncoated and coated refractory bricks using Na₂CO₃·H₂O as the corrosive agent revealed that the former were almost twice as much prone to corrosion attack. / Master of Science

A finite element procedure is used for analysis of a number of soil-structure interaction problems. This procedure involves one dimensional beam-column element, two-dimensional (rectangular) plate element, and nonlinear foundation represented by a series of springs. The behavior of the latter is simulated by using a special form of the Ramberg-Osgood Model. The nonlinear analysis is performed by using an incremental iterative scheme. The procedure is used to predict behavior of a number of problems such as beams and plates on elastic and nonlinear foundations, building frame and foundation, and cap-pile-foundation interaction. The predictions are compared with closed form and laboratory observations. In the case of pile-cap-foundation analysis, a parametric study is performed to delineate the effects of the relative stiffness of the cap, pile and nonlinear soil. The comparisons between the predictions and observations has been found to be satisfactory. / Master of Science

The National Aeronautics and Space Administration's Space Shuttle employs a solid rocket propellant. Combustion of the solid propellant produces hydrogen chloride as one of the major products. In this thesis, the hydrogen chloride/silica system was investigated. Silica was chosen as a model compound to represent ground debris transported into the exhaust cloud as a result of convection. The silica adsorbent was characterized by x-ray diffraction, infrared spectroscopy, and surface area. Interaction of hydrogen chloride with silica (𝔞-quartz) was studied by various techniques including adsorption/readsorption isotherms, ESCA, and calorimetry. Adsorption of hydrogen chloride at 30°C was found to be dependent on the outgas temperatures and reversibility was dependent on the reoutgas temperatures. ESCA analysis on silica after exposure to HCl. indicated the presence of chloride ion. Angular probe studies showed that the chloride ion resides on the surface of silica rather than in the bulk of the sampling region. Calorimetric work was performed to measure heats of immersion of silica outgassed at various temperatures in different concentration of hydrochloric acid. Heats of immersion were found to increase with increasing outgas temperature and concentration of acid. Similar investigation of the hydrogen chloride/silica system was then extended to ground debris samples from the Kennedy Space Center. These samples were characterized by SEM/EDAX. The amount of HCl adsorption per unit area was more than three times greater than on pure silica. Apparently, HCl has a greater affinity towards some component of the ground debris other than silica. / Master of Science