The rates of reaction of pulverized samples (100-200 mesh) of blaubleibender covellite and covellite with 10⁻³ m ferric iron in a pH 2 solution were determined at 25, 35, and 50°C. Ferrous and cupric ion concentrations of the run solutions suggest that parallel reactions oxidized the sulfur to either elemental sulfur or to sulfate. The reaction that produces elemental sulfur is by far the fastest. The disappearance of ferric iron follows a first-order rate law which is a combination of the two first-order reactions: -dm_Fe3+/dt = (k₁ + k₂) (A/M) m_Fe3+ where m_Fe3+ is the molal concentration of uncomplexed ferric iron, k₁ and k₂ are the rate constants and A/M is the ratio of the surface area of the reacting solid to the mass of the solution. At 25°C the measured rate constants are 7.14 x 10⁻⁵ ± 1% sec⁻¹ for blaubleibender covellite and 9.4 x 10⁻⁴ ± 1% sec⁻¹ for covellite indicating that blaubleibender covellite reacts almost an order of magnitude faster than stoichiometric covellite under these conditions. However, the activation energies for these reactions, over the temperature interval 25 to 50°C, are the same, within the range of the reported error: 51.8 ± 6.2 kJ mol⁻¹ for blaubleibender covellite and 58.29 ± -13. 7 kJ mol⁻¹ for covellite. This suggests that the rate limiting step for both reactions is the same. The relatively high activation energies indicate surface reactions control the rate of oxidation at these temperatures. / Master of Science

Reaction sintered silicon nitride (RSSN) was studied as a substitute coating material on the carbon-carbon material (RCC) presently used as a heat shield on the space shuttle, and on advanced carbon-carbon (ACC), a later development. On RCC, RSSN showed potential in a 538°C (1000°F) screening test in which silicon carbide coated material exhibits its highest oxidation rate; RSSN afforded less protection to ACC because of a larger thermal expansion mismatch. Organosilicon densification and metallic silicon sealing methods were studied as means of further increasing the oxidation resistance of the coating, and some improvement was noted when these methods were employed. / Master of Science

The purpose of this study was to seek researched responses to parental questions about the influence of Family Life education courses on family value systems. A comparison study was made between three classes of high school students. A treatment group (Human Relationships) received specific training in communication skills, intrapersonal and interpersonal skills. Two control groups (Gourmet Foods and Chemistry) followed subject course outlines. The results of independent one-way analysis of variance tests indicated significant differences on the pretest of value rankings between groups. When t tests were used to compare Human Relationships and one control group (Chemistry) they suggested that students who chose to participate in a Human Relationship course of study brought with them a set of values different than those who did not select such a course. Although this was only a formative study it would seem to support the current theory that high school students are responsive to and reflective of their family value system. / Master of Science

The major objectives of this study were to: 1. evaluate the financial aspects of improvement thinnings for fuelwood in Appalachian hardwood stands. 2. determine direct net energy values from energy inputs and outputs for fuelwood harvesting in Appalachian hardwoods. The landowners decision on whether or not to thin was greatly influenced by haul distance and his opportunity cost for time spent harvesting wood. Other considerations included the market price for both firewood and firewood stumpage. Two cases were analyzed using discounted cash flows, the first considered the landowner as a firewood consumer. The results of this portion indicated that at low haul distances (< 15 miles) and low opportunity costs ($0 to 5 per hour), the landowner should produce his own firewood. At longer haul distances an open market purchase should be made and at higher opportunity costs a contractor should be hired to harvest the firewood. In the second case, the landowner acted as a firewood producer. The results indicate that at low haul distances and low opportunity costs of harvesting, the landowner can attain reasonable rates of return on the investment (approximately 4% after-tax in real terms). At greater haul distances and higher opportunity costs the investment returns diminish. The second objective concerning energy resulted in favoring larger scale operations at longer haul distances and smaller operations at shorter distances. The major influences on energy values were haul distance and degree of mechanization. Overall, this analysis presents a process for evaluating firewood thinnings and offers the landowner the capability of examining a variety of sites and harvest systems. However, the results should be viewed only as an example situation. / Master of Science

The focus of the current study was to determine if there was an association between features of the social environment and both oral and silent reminiscence frequency. Fifty community-dwelling older adults (aged 58-84; 60% female) participated in the study, which utilized a questionnaire. Current opportunities to reminisce were significantly associated with both oral and silent reminiscence frequency; early life experience with reminiscing was significantly associated with total (oral plus silent) reminiscence frequency (p<.05, one-tailed). Perceived enjoyment, appropriateness, and usefulness of reminiscing were also measured. Silent reminiscence frequency was significantly higher than oral reminiscence frequency for the total sample (p<.001). Gender differences were also significant for oral reminiscence frequency (p<.02), combined reminiscence frequency (p<.05) and usefulness (p<.04) with males scoring higher than females in each case. Results suggest that researchers and practitioners should take into account features of social interaction as well as demographic characteristics before initiating reminiscence research and therapy. / Master of Science

Several crops are being touted as a renewable energy source. Sweet sorghum is adapted to many areas, grows relatively rapidly, has moderate water and nutrient requirements, and develops high levels of fermentables. A long term supply of fermentables is needed to make ethanol production economically feasible. Short term availability of fermentables results in unfavorable returns from investments in equipment and crop production. Two planting dates (15 May and 1 June) and eight harvest dates (30 Sep. to 15 Mar.) were used in efforts to to extend the availability of sweet sorghum fermentables. Respiration of sweet sorghum tissue was measured with an infrared gas analyzer before and after freezing to quantify loss of fermentables associated with delayed harvests. Vital stains were used before and after freezing to estimate cell mortality. No significant difference was found in the level of fermentables in sorghum from the two planting dates. Delay-ing harvest caused fermentables to decline significantly (30%) by mid-November and to continue to drop through March. Respiration dropped 90% after exposure to -8 C, but resumed the same rate after 1 week. Vital stai!1ing showed cells die upon freezing. Relatively high respiration rates in the dead tissue suggests saprophytic microbes are responsible for the large decline in fermentables after freezing. Eleven cultivars and lines were tested for yield of fermentables. Wray was superior in yield of fermentables, while Sumac and Sugardrip were inferior. / Master of Science

Results of an experimental study of the failure and crippling of thin-walled open section prismatic compression members are presented. Twenty-four specimens were tested, 13 of which were channel sections and the other 11 were zee sections. Three specimens were made of 2024-T3 aluminum. The remaining 21 specimens were made of AS4-3502 graphite-epoxy. All specimens were tested to failure. Seventeen specimens exhibited local buckling of flanges and webs prior to failure, four exhibited global column buckling prior to failure, two exhibited material short column failure, and one exhibited unstable postbuckling behavior prior to failure. The buckling loads for each specimen were also calculated by a computer code and compared to experimental buckling loads. Good correlation was achieved for specimens that did not buckle as columns. The graphite-epoxy specimens which buckled locally had significant postbuckling response prior to failure at a maximum load (crippling). Differences in the crippling failure and compressive strength failure are discussed for the graphite-epoxy specimens. / Master of Science

Small (48-54 g) and large (58-64 g) or low (≤1.070) and high specific gravity (≥1.080) eggs from broiler breeder flocks were used. The hatching sequence was divided into four periods with 25% of the chicks being hatched in each period. One-half of each group was weighed and returned to the hatcher and the remainder were placed in floor pens. Hatch-held chicks were removed at 21 days, l2 hrs, weighed and placed in floor pens. Effect of two post-hatch holding times (0 and 30 hrs) on bursa and spleen weights were measured through 35 days of age. Hematocrits, heterophil/lymphocyte ratios, plasma proteins and glucose were measured through 11 days of age. Broilers from large vs small eggs were 10% heavier and had lower mortality at 49 days of age. Chicks that were held for extended time in the hatcher had lower body weights throughout the growing period. Held chicks had 1.6% (Exp 1) and 2.1% (Exp 2) lighter body weights at 49 days of age than removed chicks. No effect on body weight was observed for egg specific gravity. Relative bursa and spleen weights were lower in held chicks through 14 days of age. Total plasma protein (TPP) and glucose levels were higher in the held chicks at 1, but lower at 3 days of age. Heterophil/lymphocyte ratios were higher in held females at 3 and 5 days and males at 3 days of age. Females had higher TPP levels through 5 days and hematocrits through 11 days of age. / Master of Science

The composition of the non-starch polysaccharides in sweet potato was determined and their flatulence-inducing potential evaluated. A preparative adaptation of the AOAC enzymatic method was used to isolate the insoluble and soluble non-starch polysaccharides. The insoluble non-starch fraction was mainly cellulose, but contained a substantial amount of hemicellulosic glucose, suggesting the presence of an independent glucan fraction. Relatively small amounts of xylose, galactose, arabinose, mannose, rhamnose and fucose were present. Galactose was the predominant sugar in the soluble non-starch polysaccharide fraction, although substantial quantities of arabinose and mannose were also present. Xylose, rhamnose, glucose and fucose were also present in small quantities. Uronic acids also made up a substantial portion of the soluble non-starch polysaccharides. Appreciable protein and ash were present in both the insoluble and soluble NSP fractions. The in vitro test for gas production using Clostridium perfringens as a test organism showed that both the insoluble and soluble non-starch polysaccharides are potential flatulence-inducers in sweet potato. However, the presence of the hemicellulosic glucans in the insoluble fraction make the latter a more likely candidate for flatus-inducer. / Master of Science

Hormonal and metabolic responses to submaximal exercise were studied in 11 sedentary, overweight women who participated in an 8 week aerobic exercise program (80% VO2 max) while consuming a hypocaloric diet. A maximal and submaximal treadmill exercise test were performed before and after the program. During the submaximal exercise test, a graded portion (mean time 6.4 min) preceded the submaximal phase during which subjects worked at 80% VO2 max until exhaustion (mean time l2 min). Blood was sampled before and after the work via venipuncture. Whole blood was immediately analyzed for lactate accumulation. The remaining blood was centrifuged, separated, and frozen for subsequent serum glucose, cortisol, and insulin measurement. There was a significant increase in oxygen uptake (ml/kg/min), and a decrease in body weight, ( 6.7%), and body fat (14%). Resting heart rate was significantly lower post-training (5.4%), as were exercise RQ (VCO2/VO2) ratios. Pretraining serum glucose and blood lactate significantly increased while nonsignificant decreases were noted in insulin and cortisol as a result of the submaximal exercise bout. The significant increases in glucose and lactate during exercise were blunted after the training program. However, only the post-training response of lactate was significantly different from the pretraining response. The insulin and cortisol response was not significantly different from that during the pretraining exercise test. A correlation was observed between RPE and lactate at the end of exercise both pretraining and post-training. In summary, the combined exercise and weight loss program resulted in exercise being less stressful, both metabolically and subjectively. This improvement enables greater exercise intensity to be performed prior to the significant accumulation of lactate and perception of fatigue which may inspire the sedentary, overweight female to establish and/or continue a regular exercise program. / Master of Science