The crystal structure of hemimorphite, Zn₄Si₂O₇(OH)₂H₂O, has been refined from X-ray intensity data collected at 300°, 600°, and 22°C (after heating to 600°C). The space group throughout the experiment was Imm2, Z=2, and the cell dimensions at each temperature, in the above-mentioned order, are: a=8.337(5), b= 10.724(6), c=5.116(4)Ȧ; a=8.268(5), b=10.784(8), c=5.113(3)Ȧ; and a=8.206(4), b=10.815(6), c=5.089(2)Ȧ. Anisotropic least-squares refinements resulted in unweighted R-factors of 0.046, 0.074, and 0.061, respectively. The structure can be described as a framework consisting of interconnected corrugated sheets composed of 3-membered rings of one SiO₄ and two Zn(OH)O₃ tetrahedra. Heating to 600°C, causing dehydration, along with subsequent cooling to 22°C resulted in the contraction of a and c, expansion of b, and a decrease in the unit cell volume. The unit cell volume decrease is directly proportional to the volume decrease of the cavity initially containing the water molecule. These changes are rationalized in terms of atomic positional shifts, especially those of the hydroxyls which are no longer hydrogen-bonded to a water molecule. The hydroxyls move towards the position occupied by the water molecule prior to dehydration. The effects of dehydration on the crystal structure of hemimorphite were to found to be similar to those found in some zeolites. Although hemimorphite may not qualify for a molecular sieve due to its small aperture size, it may be useful as an isotopic sieve. / Master of Science

The most importunate problem in using bermudagrasses (Cynodon sp.) for turf in the northern extremity, where semitropical grasses are adapted, is winter survival. This research was primarily conducted to investigate the effects of deacclimation of dormancy, duration of dormancy, and freezing temperatures on survival of bermudagrasses. 'Tifgreen' bermudagrass taken from the field in February, 1976, was deacclimated for 0, 2, 4, or 8 days at 27C/13C (day/night). Subsequently, rhizomes and stolons were subjected to +2, 0, -2, -4, or -6C for 24 hours. One third of the samples from each treatment were planted after 0, 45, and 90 days storage at 2.8C±1.6C. Rhizomes and stolons subjected to -4 or -6C did not survive. Deacclimation of rhizomes up to 8 days augmented growth as compared to no deaccli~ation. Increased storage periods caused decreased rhizome growth. At +2 and 0C, the percent rhizome growth was similar but significantly higher than at -2C. With 0 storage, stolon growth declined after 8 days deacclimation; however, after 45 or 90 days of storage, significant reductions occurred after only 4 days deacclimation. Fully deacclimated as well as dormant field samples of 'Midiron', 'Tifdwarf', 'Tifgreen', 'Tifway' and 'Tufcote' taken in March and April, 1977, were subjected to -2, -4, and -6C. All cultivars survived -4C whether dormant or actively growing. 'Tifgreen' bermudagrass frozen while dormant and 'Tifgreen' and 'Tifdwarf' frozen while actively growing had high recuperative potentials during regrowth. Comparing these cultivars under field conditions showed best winter survival for 'Midiron', which was the only cultivar that survived with simulated traffic. Traffic imposed immediately prior to bermudagrass dormancy reduced spring recovery more than for traffic imposed during winter. / Master of Science

A cylindrical-parabolic solar collector was thermally optimized for a winter season using a weather model and an extension of the present state-of-the-art collector theory. An accurate model for the cover transmittance and a seasonal performance model was developed. The optimum collector dimensions and materials were found to be a strong function of the design operating temperatures. The optical and thermal losses of a cylindrical-parabolic collector were compared and the results showed that the major loss for process heating temperatures was heat lost by natural convection. Reflection and cover losses were the next largest losses. Comparison of a flat-plate collector with a cylindrical-parabolic collector showed that a cylindrical-parabolic collector appears better suited for process heating than domestic hot water or space heating. Glass and plastic covers were analyzed and the optimum collector slope was obtained. The investigation resulted in a better understanding of how different collector dimensions and materials affect collector performance. / Master of Science

Eastern Bluebirds (<i>Sialis sialis</i>) were found to be utilizing natural nest sites in the vicinity of Blacksburg, Virginia, during 1976 and 1977. Forty-seven natural nest sites, 37 in fencepost cavities and ten in tree cavities were discovered by driving roads in rural areas, scanning fencerows and utility wires with binoculars, and by searching fencerows on foot. Ninety-one percent of nest cavities used by bluebirds were made by woodpeckers. Height of cavity entrance, entrance diameter, and distance from entrance to cavity bottom were best able to distinguish anong bluebird fencepost nest cavities, nest demonstration display sites, and Starling (<i>Sturnus vulgaris</i>) fencepost nest cavities, using discriminant function analysis. Four nest cavities used by bluebirds in 1976 were no longer available in 1977 due to the replacement of fenceposts and tree limb breakage. No new cavities in fenceposts were observed being excavated by woodpeckers. / Master of Science

This study was designed to measure the effect of selected consumer practices on energy consumption of refrigerators. Seven tests designed to simulate consumer practices were performed three times each on four refrigerators. Four tests involving variations in temperature control setting, frequency and duration of door openings, and placement of the refrigerator near a heat source were each performed on a manual-defrost refrigerator, a cycle-defrost refrigerator-freezer, and a no-frost refrigerator-freezer. A test involving the use of an energy-saver switch was performed on a no-frost refrigerator-freezer, and two tests related to the effect of frost accumulation on energy consumption were performed on a manual-defrost refrigerator. Watt-hour consumption and interior cabinet temperature were recorded for all tests. Increasing the temperature control setting, frequency of door openings, and duration of door openings; the use of an energy-saver switch; and the defrosting process all increased the energy consumption of the refrigerators. Operating the refrigerator near a heat source did not affect energy consumption to the extent of the other tests. Due to inconsistent results, the effect of frost accumulation on energy consumption needs further investigation. / Master of Science

This study is a systematic and ethnobotanical treatment of the genus Ipomoea in Oaxaca, Mexico. This taxon merits deeper investigations because of present disorganization and disaccord in its classification on generic, subgeneric, and species levels. A second facet of the investigation involves an ethnobotanical survey on past and present nutritional, medicinal, and shamanic uses of these plants. The taxonomic study involved acquisition of herbarium materials from various sources with review of past descriptions and sectional organizations of the genus. Morphological.relationships were correlated with phytochemical data from collected plant materials from Oaxaca. A key to species, species descriptions, and sectional organization of the genus were constructed by these studies. A survey of plant uses was also compiled with reference to the relationships of these plants and their utilizations. / Master of Science

The effect of blade profile variations on the erosion of turbine blades subjected to flow containing particulates was analytically determined. To accomplish this end, the two-dimensional inviscid main flow field was determined for each blade passage. A semi-empirical model of erosion was combined with available experimental data to predict erosion on the blade surfaces. Maximum erosion was found to be at the trailing edge of the stator and rotor and at the leading edge of the rotor. The trailing edge erosion of the stator and rotor was decreased as the blade exit angle was decreased. The trailing edge erosion of the stator and rotor was also decreased when the blade leading edge radius was reduced. Reducing the degree of reaction of the turbine stage caused a change in distribution of erosion levels along the blade surface. / Master of Science

The effect of kinetin concentrations (10⁻⁶M and 10⁻⁴M) on distribution of free fatty acids and sterols in plant parts and root exudates of 57-day-old peanut plants grown in nutrient solutions under gnotobiotic conditions was studied. Kinetin was applied to the roots in the culture medium five days before harvest. Upon harvesting root exudates were collected and plants divided into leaves, stems, and roots. The extracted lipid fraction was partitioned using silica gel thin-layer chromatography. Quantitation and identification of free fatty acids and sterols were accomplished by isothermal gas-liquid chromatography. On the basis of ug fatty acid/mg tissue and ug fatty acid/mg lipid kinetin caused no significant changes in total fatty acid concentration. The only significant increase in total sterol concentration was observed in the 10⁻⁴M treatment (ug sterol/mg lipid) in the stems. Use of individual component concentrations, relative percentages, and ratios helped distinguish trends. Shifts in quantity and quality of the free fatty acids and sterols may have been a result of one or a combination of effects attributed to kinetin. Decrease in root exudation in the 10⁻⁶M treatment may have been due to altered membrane integrity. Increase in the sitosterol/ stigmasterol ratio in stems of treated plants may have been a result of delayed senescence. Trends showed transport of free fatty acids and sterols to the roots in 10⁻⁶M treated plants. Kinetin may have effected sterol concentration through changes in HMGCoA reductase activity by unsaturated fatty acids. / Master of Science

Within the cyclic order of history, the Modern Age may be seen to have an emphasis on constructive creativity contributing to its progression away from a natural formative basis for order. As a fundamentally different paradigm to post-modern design approaches, a natural formative basis may be seen to embody the dual of 'organic ordering' and 'natural ordering': An inherent dualism in intuitive creative potential, the manifestation of which embodies truth, beauty and harmony. 'Natural ordering' is becoming increasingly important to energy conscious design of the post-modern age, representing a lost creative potential held latent by the emphasis on industrial-founded environmental control technology. / Master of Architecture

The feasibility of obtaining improved fuel efficiency by incorporating a hydrostatic transmission was investigated. The proposed transmission was composed of positive-displacement axial-piston hydraulic devices. The displacement of the pump and motor units could be varied to allow the prime mover to operate within its most efficient range. A dynamic model representing a Ford Pinto was developed using bond graphs and the IBM CSMP language to simulate the performance of the proposed design. The required input to this program consists of three independent, or control variables. These are the pump and motor swashplate angles and the engine throttle angle. In present form, the output of this program includes instantaneous values of vehicle velocity, pump and motor efficiencies, engine bsfc, and fuel economy. Observations from the simulations indicate that the test vehicle is capable of exceeding the EPA highway fuel economy estimates for the 1978 production Pinto by 11%. This increase in economy is a result of operating the engine near the minimum bsfc. Although comparisons were not made in this study, it is believed that even higher increases in economy may be realized in urban-type periods of operation. / Master of Science