Academic literature on the topic 'LD5655.V856 1987.S524'

A land use planning model was developed for long term planning of renewable natural resources development in the Hills of Nepal. Considerable emphasis was placed upon identifying land use planning problems for the prevalent limited market economy and subsistence farming system. A multiobjective programming model was chosen for modeling the land use planning problem. The model accommodated five objectives: namely, increasing food, fodder, and fuelwood production and decreasing soil loss and cost. A weighting technique within the multiobjective framework was developed to facilitate land use planning as a socio-political decision making process. The application of the model was demonstrated with data from Phewatal watershed. The model generated technically efficient alternative land use plans. It also generated information on time flow of achievement levels of the objectives and their trade-offs in each alternative plan. Very few alternative plans were generated when the periodic growth rates on achievement levels of the objectives were tightly constrained. The model also provided information on periodic deficit and surplus achievements of the objectives. This information provided the guidelines for evaluating the plans. The model provided a useful mathematical structure for analyzing land use planning as an integrated planning process coordinating multi-sectoral objectives in time and space. A foundation has been laid for constructing comprehensive land use planning models in subsistence farming economy in developing nations. The model was run on a commercially available software package and a portable personal computer. Therefore, the model can be applied in the field situation in many developing countries.
Ph. D.
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Twenty-five gay men, 20 with Acquired Immune Deficiency Syndrome (AIDS) and 5 with either AIDS Related Complex (ARC) or who tested positive for the AIDS virus, were asked in semi-structured interviews whether they felt supported or isolated. Areas covered included society in general, employment, housing, health care, insurance, religion, families of origin, ex-wives, children, friends and lovers. Subjects indicated that fear of AIDS, homophobia, and death anxiety were all present in certain circumstances, but there was no attempt to differentiate between these three possible causes of social isolation in this exploratory study.
Master of Science

Composite laminates are prone to delamination at free edges, straight edges or at holes, due to the mismatch at interfaces where two adjacent plies have different fiber orientations and/or different material properties. The linear analysis of the mismatch at the edge results in a mathematical singularity. That phenomenon occurs in a boundary layer and has to be treated mathematically and physically as such. In the literature it is called the "Boundary Layer Effect" or simply the "Edge Effect". It is of great importance to recognize and be able to predict delamination locations at edges prone to such events. The goal of this research was to create a model capable of providing such a prediction. In an effort to generalize the model, the more complicated case of a free edge at holes in the composite laminate was chosen rather than the case of a straight free edge. A sequel of three major efforts was completed: 1) Development of the analysis of the free-edge effect at a hole in a composite laminate, 2) Performance of an extensive experimental program to provide data for the creation of the prediction model, and 3) On the basis of the analysis, establishment of the model, and comparison with the experimental results. The prediction model consists of two major products of the analysis, the order of the singularity and the strain energy release rate. Both are useful in locating the interface most prone to delaminate and the point along the hole circumference where it initiates. Two material systems (AS4/3501-6 and AS4/1808) and two stacking sequences [(0/45/0/-45)_s)₄] and [ (0/45/90/-45)_s)₄]s , quasi-orthotropic and quasi-isotropic respectively, were quasi-statically tested under tension and compression. The specimens were X-rayed after each loading stage in order to locate the initiation of delaminations. The fact that both materials consisted of the same type of fibers, was an excellent opportunity to examine the performance of the matrix and its influence on the process of delamination. Matrix dependent behavior was successfully examined and studied through the experiments and the prediction model. Results showed good correlation and high sensitivity to the type of matrix material involved.
Ph. D.

Anodized Ti-6Al-HV/adhesive bonds exhibit improved corrosion resistance and a higher strength-to-weight ratio compared to conventional metal bonding techniques for primary and/or secondary structural applications. This work was conducted to identify chromic acid (CA) anodization and bond process conditions which produced durable, structural anodized Ti-6Al-4V/heat resistant single lap bonds and to understand why these conditions were necessary. A structural single lap bond was defined as a bond tested at 298K ≤ 0.5 month after bonding and with a strength ≥ 6.9 MPa, based upon values reported in structural adhesive manufacturers' product literature. A durable, structural single lap bond was defined as a bond with a strength ≥ 6.9 MPa strength at 298K after 9 months aging at 433K. Heat resistant adhesives tested had reported service temperatures ≥ 423K, and were: polysulfone; eolyethersulfone; polyphenylquinoxaline; polyetherimide, both unfilled and 20% glass filled; and 50% calcium carbonate filled polyimide. Hydrofluoric acid (HF) added to the CA anodization solution was necessary to produce structural bonds. CA/HF oxide was more porous, and thicker than the CA anodic oxide (140 nm vs. 20 nm), perhaps promoting physical and oxide/adhesive interphase mechanical interlock. Structural, durable CA/HF anodized Ti-6Al-4V-adhesive bonds were produced for all adhesives tested except for the filled polyimide (5.5 MPa). The filler may have occluded oxide pores and prevented optimal adhesive/oxide interphase interlock, and there may have been competition of polyimide for calcium carbonate filler and for oxide. Average oxide thickness values of 65 to 410 nm did not affect bond strength; structural bonds were produced in all cases. CA/HF initial current density of 20 Amperes per square meter produced 33% stronger polysulfone bonds than 30 Amperes per square meter. Polysulfone microstructure may have been chemically degraded by the unnecessarily high fluoride concentration in the oxide from the higher current density. Lica® 44 titanate primer did not significantly influence bond strength or durability, except when unfilled polyetherimide was the adhesive. Polyphenylquinoxaline bond processing influenced bond strength. Structural bonds resulted for all the CA/HF anodization and process conditions described above. Single Iap bond fracture initiated in the adhesive (polymer) fillet. Fracture propagation in the bond overlap was through the polymer/anodic oxide interphase and/or cohesively in the polymer.
Ph. D.

The genome of bovine parvovirus (BPV) has been cloned by blunt end ligation of double-stranded virion DNA into the plasmid pUC8. The resulting genomic clones were infectious after transfection into bovine fetal lung (BFL) cells. Sequencing of the plasmids demonstrated that deletions were common at both ends of the cloned BPV genome. Deletions of up to 34 bases at the 3’ end lowered but did not abolish infectivity, while a deletion of 52 bases eliminated infectivity, End label analysis demonstrated the repair of deletions of up to 34 bases at the 3’ end or 35 bases at the 5’ end to the wild type length. Mutually inverted sequence orientations of the palindromic termini, known as the flip and flop forms, can occur during replication of parvovirus DNA. Cloning of BPV terminal sequences permitted the identification of the 3’ flop sequence inversion as a natural component of BPV DNA. This is the first report of sequence inversions within the 3’ end of an autonomous parvovirus. Clones with the 3’ flop or flip conformations were equally infectious. Wild type virion DNA was shown to have predominantly the 3’ flip conformation but a significant amount of 3’ flop was also detected. At the 5’ end, both the flip and flop sequence conformations were identified in nearly equal amounts. The progeny virion DNA from transfection of genomic clones had the same ratio of flip to flop as did wild type at both the 3’ and 5’ ends, regardless of the starting terminal conformations of the genomic clone. These data suggest that, while sequence inversion occurs at both termini during BPV DNA replication, some mechanism exists for the preferential replication of the 3’ flip conformation. Replicative form DNA from BPV infected cells had the same ratio of flip and flop at each end and the same termini as virion DNA. A set of deletion and frameshift mutants affecting each of the coding regions of BPV was constructed using one of the genomic clones. None of these mutants was infectious when transfected into BFL cells, which demonstrates that all three of the major open reading frames are essential for the production of infectious virus.
Ph. D.
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Changes in metabolic substrate utilization patterns resulting from exposure to varying humidity and dietary regimens were examined in the adult, male American cockroach. A series of respirometric experiments were conducted to monitor changes in respiratory quotient (RQ), oxygen quotient (QO₂), food and water consumption and body weight. Also, a series of radiolabel experiments, utilizing injected ¹⁴C-glucose and ¹⁴C-palmitic acid, were conducted to determine radiolabel content (after exposure to varying humidity and dietary regimens) in whole body, feces, ¹⁴CO₂, hemolymph, fat body tissue and cuticle. The results of these two series of experiments were compared to determine the overall effects of humidity and diet on catabolic substrate utilization pattern changes in the American cockroach. In these experiments, variation in dietary regimens appeared to play a more significant role than humidity variations with respect to significant differences observed in insect RQ, QO₂, body weight and radiolabel incorporation in whole body, ¹⁴CO₂ , hemolymph, and fat body tissue. However, humidity significantly affected radiolabel incorporation in fat body tissue in the glucose experiments and ¹⁴CO₂ in the palmitic acid experiments. RQ and QO₂ data from the respirometric experiments and ¹⁴CO₂ data from the radiolabel experiments suggested that cockroaches deprived of food, but provided water to drink, change their metabolic substrate utilization pattern from initial catabolic substrates such as carbohydrates to lipid-based substrates. Also, cockroaches deprived of either water (FO) or food and water (OO) appeared to change metabolic substrate utilization patterns toward carbohydrates, but the final carbohydrate metabolic substrates are still unknown. Cockroaches provided water, but no food, showed a change from initial RQ values (low humidity OW = 0.92 and medium humidity OW = 0.86) to terminal RQ values (low humidity OW = 0.71 and medium humidity OW = 0.68) representative of lipid-based substrate metabolism. There was also an unexplained decrease in QO₂ (initial low humidity OW = 0.45 ul/mg/hr and terminal low humidity OW = 0.28 ul/mg/hr; initial medium humidity OW = 0.35 ul/mg/hr and terminal medium humidity OW = 0. 30 ul/mg/hr). Also, cockroaches deprived of water (FO) or food and water (OO) showed an overall experimental rise in RQ values (initial low humidity FO = 0.87; and terminal low humidity FO = 0.87; initial medium humidity FO = 0.82 and terminal medium humidity FO = 0.85: initial low humidity OO = 0.79 and terminal low humidity OO = 0.88; initial medium humidity OO = 0. 75 and terminal medium humidity OO = 0.87). In addition, these same insects showed an overall experimental increase in QO₂ (initial low humidity FO = 0. 34 ul/mg/hr and terminal low humidity FO = 0.43 ul/mg/hr; initial medium humidity FO = 0.45 ul/mg/hr and terminal medium humidity FO = 0.49 ul/mg/hr: initial low humidity OO = 0.37 ul/mg/hr and terminal low humidity OO = 0.53 ul/mg/hr; initial medium humidity OO = 0.32 ul/mg/hr and terminal medium humidity OO = 0.45 ul/mg/hr), and in the radiolabelled glucose study OO insects showed an almost complete cessation of ¹⁴CO₂ release at 2 days (d). Terminal body weights differed significantly among cockroaches provided with both food and water (controls = FW), only water (OW), only food (FO) and no food or water (OO). Insects deprived of either water (FO) or food and water (OO) had significantly lower terminal body weights than those insects provided either water or food and water. Whole body water content increased and dry weight decreased in insects provided only water to drink.
Ph. D.

Two experiments were conducted to evaluate the effects on applied force of structural design parameters and feedback conditions inherent in the aesthetic overlay of membrane switch touchpads. In the first experiment, which evaluated structure, 12 males and 12 females keyed 100 4-digit sequences into a computer using 6 of a total of 12 touchpads which differed in membrane ply thickness, spacer thickness, and spacer aperture diameter. The same task was completed by nine males and nine females in the second experiment, which evaluated feedback conditions inherent in flat, embossed, domed, embossed with dome, flat with escutcheon, and domed keycap aesthetic overlays. The apparatus employed for force measures was a force platform system integrating seven strain gauge force transducers. Subjects received auditory feedback for correct actuations. Results of the studies indicate that applied forces are correlated quite highly with the required actuation force (RAF) of the switch (r = 0.89, p < 0.01). However, membrane switch structure had a significant effect on the applied forces, even after the effects of RAF were controlled. Feedback conditions inherent in the aesthetic overlay also had an effect on the forces applied. A significant preference for RAF was found in the structure experiment. There were no significant differences among touchpads with respect to preference for feedback conditions inherent in different aesthetic overlays.
Ph. D.

Wide-bore, fused-silica capillary columns can be an excellent replacement for packed columns in many cases. They can provide higher surface inertness and thermal stability, as well as higher efficiency or speed of analysis. Wide-bore, open-tubular (WBOT) columns with thick films have higher sample capacities than conventional narrow-bore capillary columns and can be used in unmodified packed-column gas chromatographs.

The majority of gas chromatographic analyses are still performed using packed columns. Many chromatographers associate open-tubular columns exclusively with split injection, often perceived as less repeatable or quantitative. Also, many packed-column methods use application-specific stationary phases which are not readily available on capillary columns. WBOT columns with standard phases can often be substituted due to higher available efficiencies. While several studies have been published on qualitative differences, there is little comparative quantitative data available on O.53â mm I.D. and packed columns.

Master of Science

The water distribution system design problem consists of finding a minimum cost combination of network layout and sizes of system components so as to satisfy flow demands, minimum and maximum head requirements and a reliability criterion. A two step procedure is proposed to find a near optimal design. The first step considers obtaining a near optimal tree layout using a heuristic tree search algorithm. Two different methods are followed for the tree search - one for single source networks and the other for multiple source networks. The second step adds loop forming redundant links to the tree layout in such a way that every demand node has two paths from source node(s). The methodology is applied to a single source network and a multiple source network. In both the cases better results arc achieved than those obtained previously by other researchers.
Master of Science

Distribution and bioavailability of ⁴⁷calcium in milk labeled by extrinsic and intrinsic methods was investigated. Milk from Sprague Dawley rats was labeled by both methods, and milk from a cow was labeled by the extrinsic method. Retention of ⁴⁷Ca from milks administered to young male Sprague Dawley rats was determined through whole body counting for 6 days after administration of milk. Percent of ⁴⁷Ca dose retained was 72% for extrinsically labeled cow milk, 62% for extrinsically labeled rat milk, and 55% for intrinsically labeled rat milk. Samples were fractionated by ultracentrifugation and by gel exclusion chromatography. ⁴⁷Calcium distributions in rat milk labeled intrinsically or extrinsically were similar. The majority of ⁴⁷Ca was found in a particulate, > 30,000 molecular weight fraction (about 60% for cow milk, about 90% rat milks). The amount of milk calcium retained by rats appeared to be related to the amount of noncasein micelle-associated calcium. When administered by intraperitoneal injection into rats, ⁴⁵Ca specific activity of milk peaked in 60 to 90 minutes. Specific activity was highest in cytosol, and lower in Golgi apparatus and rough endoplasmic reticulum. Specific activities in subcellular fractions changed in parallel with specific activities of milk. Rapid turnover of Ca was observed in endoplasmic reticulum and Golgi apparatus; this was expected since secretory proteins and associated Ca are transported through these organelles for secretion. In vitro ⁴⁵Ca accumulation was compared in Golgi apparatus and endoplasmic reticulum from liver and mammary gland of lactating Dunkin Hartley guinea pigs. In the presence of ATP, highest accumulation per unit total fraction protein was found in Golgi apparatus (mammary gland 28% of available ⁴⁵Ca, liver 11%) while 8% was accumulated by endoplasmic reticulum fractions. Calcium accumulation was not the result of binding, as preincubation of vesicles with calcium ionophore resulted in less than 10% of the accumulation found without ionophore. The ATPase inhibitor sodium orthovanadate, and the ATP analog AMP-PNP, reduced ⁴⁵Ca accumulation in all fractions. Protonophore caused a small reduction in ⁴⁵Ca accumulation in all cases. Citrate accumulation by fractions was not observed under conditions used for ⁴⁵Ca accumulation.
Ph. D.