Heat transfer in cylinder spaces is important to the performance of many reciprocating energy conversion machines, such as gas compressors and Stirling machines. Work over the past 10 years has shown that heat transfer driven by oscillating pressure differs from steady state heat transfer, in magnitude arid phase. In-cylinder heat transfer under this oscillating condition can be out of phase with the temperature difference. For studies with closed piston-cylinder gas springs, this heat transfer phase shift has been successfully predicted with the use of a complex Nusselt number. Since a complex,number has both a magnitude and a phase, a complex Nusselt number can describe the phase shift between temperature difference and heat transfer. Quasi - steady heat transfer models, such as Newton's Law of Cooling, do not predict this phase shift. In this project, the problem of in-cylinder heat transfer with inflow and outflow was studied. The goal was to determine what the complex heat transfer coefficients were under these conditions. Because methods which measure the heat transfer directly, such as heat flux gauges, only give local results, past work has used pressure and volume measurements to calculate surface averaged values for the heat transfer. This becomes much more difficult to do with inflow and outflow because of the difficulty in accurately determining how much mass is in the cylinder at any given time. Two approaches were used to overcome this problem. They are the main substance of the work presented here. The actual experimental pressure and volume measurements were taken by Kafka (Virginia Tech Master's Thesis, 1994). / Master of Science

Cumulative trauma disorders have become common among workers in industry. Grocery stores are an industry with one of the highest number of repeated trauma illnesses. Checkout departments have a rate of musculoskeletal injuries two to three times higher than other supermarket departments. The primary objective of this study was to quantify the wrist motions required to bag groceries. Subjects participated in the laboratory or in the supermarket. The wrist motions included wrist deviations, velocities, and accelerations for flexion-extension, radial-ulnar, and pronation-supination deviations. The dependent variables were handle type and object location. A wrist motion monitor designed at Ohio State University was used to quantify wrist posture and movement. Objects with finger-thumb handle couplings required more extreme ulnar deviations, more extreme pronations, greater wrist velocities for pronation-supination deviations, and greater wrist accelerations for pronation-supination deviations than did other objects. When comparing soft and solid objects, or round and square objects, there were few differences in wrist positions, velocities, or accelerations. Objects with 10-cm wide hand couplings required more extreme flexion, larger ranges of movement for radial-ulnar deviations and pronation-supination deviations, and greater wrist velocities in the radial, ulnar, and pronation directions than did 5-cm wide objects. The right and front locations required more extreme positions than did the left and back locations. Subjects participating at the supermarket site picked up objects with greater wrist velocities and accelerations than those in the laboratory; conversely, wrist positions were not affected by site. Because finger-thumb and 10-cm wide hand couplings required larger wrist deviations and greater velocities, these objects may pose a greater risk to the bagger of developing cumulative trauma disorders. / Master of Science

The responses of soybean (Glycine max (L.) Merr.) to soybean mosaic virus (SMV) include mosaic, necrosis and no symptoms, and vary with virus strain and allele of the gene for resistance (Rsv) carried by the host. Genetic studies have shown that plants giving mosaic are susceptible, and that plants giving either the necrotic or symptomless response are resistant. The objective of this study was to examine the mechanism of resistance by tracking SMV replication and movement in susceptible responses, and its restriction in necrotic and symptomless responses. Two SMV strains were inoculated at a single spot to Rsv-containing genotypes, selected to give each response. The leaf imprint immunoassay was developed and used to track the rate and extent of invasion by SMV from the tip of a primary, unifoliolate leaf to regions within that leaf and to the stem and younger trifoliolate leaves. In susceptible responses, SMV was detected at the site of inoculation in 6-7 days, and throughout the mid-rib and in the first trifoliate leaf in 8-9 days. In necrotic resistance responses, SMV was detected at and around the inoculation site in 8-9 days and in leaf veins, midrib and the first trifoliolate in 15-17 days, but was restricted to necrotic areas. In symptomless resistance responses, no virus was detected at any time. Greater virus replication and movement was found in unifoliolate and trifoliolate leaves of younger (15 days-old) than of older (18-days-old) plants. It was concluded that: (i) necrotic ally-responding cultivars manifest resistance by reduction and delay in replication, and by restriction of virus movement; (ii) virus replication is restricted in resistant cultivars; and (iii) rate and extent virus replication and movement is affected by stage of plant development. / Master of Science

This thesis has described the Chinese model of coalition politics among the central state, local authorities and foreign capital during 1979-1993. The characteristics of this model were that the local authorities and foreign capital shared more common interest with each other than with the central state, and consequently a cooperation between two was formed at the expense of the central state. / Master of Arts

Virginia bed and breakfast operations were researched in order to determine the attitudes/beliefs which were necessary for success in the bed and breakfast industry. The objectives of the study were to: (1) identify demographics of Virginia bed and breakfast operations; (2) identify successful bed and breakfast operations based upon their self definition of success; (3) identify the attitudes and beliefs operators believe are necessary for success in running a bed and breakfast operation and correlate attitudes with operators' actual behaviors; and (4) based upon the operator's self-definition of success, compare the correlations identified in the previous objective between successful and other operators. Data was collected by utilizing a mailed questionnaire. Pearson's correlation was used to determine if there were any relationships present between what attitudes/beliefs bed and breakfast operators perceived to be necessary for success and their actual behavior. Fishers r to z transformation was used ta determine if the relationship between the attitudes/beliefs perceived ta be necessary far success and operator's actual behavior was greater among successful bed and breakfast operations based upon a self definition of success. The results found that the correlation between the attitude/belief, past experience and actual past experience in hotels, restaurants, and large organizations was significant in the success group as well as high knowledge of cash flow/accounting and use of financial data. Stronger correlations were present in interpersonal skills, good relationship with employees and guests in the success group versus other group. Past experience in and knowledge of the bed and breakfast industry as well as family support were significantly correlated in the success group. / Master of Science

Three experiments were conducted to determine an efficient method of obtaining oocytes from cows via ultrasound-guided transvaginal follicular aspiration. Transvaginal oocyte recovery combined with in vitro maturation, fertilization, and culture (IVMlIVFIIVC) can produce pre-implantation stage bovine embryos and also supply a source of ova for gene microinjection. In Experiment 1, once- (IX) vs. twice-weekly (2X) oocyte recovery frequencies were compared. No differences in recovery per session were observed (IX = 6.8 vs. 2X = 6.3 oocytes/session; p>O.1 0). However, the 2X group generated more oocytes on a weekly basis (IX = 6.8 vs. 2X = 12.6 oocytes/week; p<O.OS). In Experiment 2, in vitro embryo production was compared among the groups aspirated once-weekly (1 X), twice-weekly (2X), and twice-weekly after receiving I5 mg FSH (2XF). No differences existed among the aspiration groups in the proportion of blastocysts produced following IVMIIVFIIVC (IX = 23.10/0, 2X = 26.1%, 2XF = 18.0%, % viable). However, the 2X group generated more oocytes and embryos throughout the experiment (2X = 83/318, 2XF = 38/211, IX = 58/2SI viable blastocyst/total oocytes; p<O.O5) than the other groups. A higher proportion of 2X or 2XF generated embryos were of excellent quality (2X = 60.2%, 2XF = 60.5%) compared to the IX group (37.9%) In Experiment 3, in vitro embryo development rates were compared among oocytes from follicular aspiration (TVFA) and oocytes derived from slaughterhouse ovaries (SHD). Oocytes (65%) from both sources were subjected to pronuclear-microinjection of foreign DNA while the remainder served as non-injected controls. Only control oocytes differed, with TVF A-derived oocytes developing to blastocyst more successfully than SHD oocytes (40.8% vs. 30.0olo~ p<0.05). Microinjected embryo development was similar between the groups (TVFA 15.9%, vs. SHD = 12.8% viable blastocyst/total;) with the TVFA oocytes holding a slight but non-significant numerical advantage (p>O.IO) In these experiments, twice-weekly follicular aspiration without exogenous FSH, was the best scheme of oocyte recovery. This program provided a source of consistent, high quality oocytes that responded favorable to the IVMIIVFIIVC system and microinjection. / Master of Science

C’est au XIXe siècle, avec la diffusion de la méthode expérimentale de Claude BERNARD et le passage d’une conception hiérarchisée du monde à une conception plus égalitariste, qu’apparait le conflit de valeurs qui sous-tend la problématique de l’expérimentation sur les animaux. Au XXe siècle, confortée par la thématisation philosophique de la souffrance animale, l’action des mouvements de protection et de libération des animaux contribue à l’émergence de législations ou de mesures d’autorégulation de la part de la communauté scientifique. Derrière cette préoccupation nouvelle pour le sort des animaux de laboratoire subsistent cependant des difficultés théoriques et pratiques qui constituent autant d’enjeux éthiques nécessitant la poursuite d’une réflexion pluridisciplinaire.

Layerwise finite element analyses of geodesically stiffened cylindrical shells are presented In this work. The layerwise laminate theory of Reddy (LWTR) is developed and adapted to circular cylindrical shells. The Ritz variational method is used to develop an analytical approach for studying the buckling of simply supported geodesically stiffened shells with discrete stiffeners. This method utilizes a Lagrange multiplier technique to attach the stiffeners to the shell. The development of the layerwise shells couples a one-dimensional finite element through the thickness with a Navier solution that satisfies the boundary conditions. The buckling results from the Ritz discrete analytical method are compared with smeared buckling results and with NASA Testbed finite element results. The development of layerwise shell and beam finite elements is presented and these elements are used to perform the displacement field, stress, and first-ply failure analyses. The layerwise shell elements are used to model the shell skin and the layerwise beam elements are used to model the stiffeners. This arrangement allows the beam stiffeners to be assembled directly into the global stiffness matrix. A series of analytical studies are made to compare the response of geodesically stiffened shells as a function of loading, shell geometry, shell radii, shell laminate thickness, stiffener height, and geometric nonlinearity. Comparisons of the structural response of geodesically stiffened shells, axial and ring stiffened shells, and unstiffened shells are provided. In addition, interlaminar stress results near the stiffener intersection are presented. First-ply failure analyses for geodesically stiffened shells utilizing the Tsai-Wu failure criterion are presented for a few selected cases. / Ph. D.

In product design, tolerances are specified due to the inherent variabilities of manufacturing processes. Tolerance specifications have significant implications on the quality and cost of the product. For proper tolerance specification, tolerance analysis must be performed. Prototyping is the the only method available for the analysis of the product geometric variations. For the automation of the analysis procedure, the part tolerance information must be represented in a format suitable for computer interpretation. Previously proposed tolerance representation schemes have suffered either from inadequate variational coverage or departure from the established ANSI tolerancing standards. Toward this end, a tolerance representation scheme capable of modeling the range of tolerances defined in the ANSI Y14.5 standard in a format suitable for automated tolerance analysis has been proposed. One unique feature of this representation scheme is the use of B-splines for the modeling of form variations. The representation scheme can also take into account the distribution characteristics of the manufacturing processes used to enable statistical tolerance analysis. To provide an accurate characterization of the variational form characteristics of the manufactured part features, the use of process capability templates was introduced. For assembly tolerance analysis, a relative positioning scheme capable of modeling the interaction between mating splines was developed to propagate the individual part variations within the assembly. This enabled the tolerance stackup on the assembly design function(s) to be computed automatically without the need to formulate any tolerance functions. A prototype software, written in the C++ programming language and running from within CATIA, has been developed to demonstrate the integration of the above concepts. / Ph. D.

The probabilistic approach to design optimization has received increased attention in the last two decades. It is widely recognized that such an approach should lead to designs that make better use of the resources than designs obtained with the classical deterministic approach by distributing safety onto the different components and/or failure modes of a system in an optimal manner. However, probabilistic models rely on a number of assumptions regarding the magnitude of the uncertainties, their distributions, correlations, etc. In addition, modelling errors and approximate reliability calculations (first order methods for example) introduce uncertainty in the predicted system reliability. Because of these inaccuracies, it is not clear if a design obtained from probabilistic optimization will really be more reliable than a design based on deterministic optimization. The objective of this work is to provide a partial answer to this question through laboratory experiments — such experimental validation is not currently available in the literature. A cantilevered truss structure is used as a test case. First, the uncertainties in stiffness and mass properties of the truss elements are evaluated from a large number of measurements. The transmitted scatter in the natural frequencies of the truss is computed and compared to experimental estimates obtained from measurements on 6 realizations of the structure. The experimental results are in reasonable agreement with the predictions, although the magnitude of the transmitted scatter is extremely small. The truss is then equipped with passive viscoelastic tuned dampers for vibration control. The controlled structure is optimized by selecting locations for the dampers and for tuning masses added to the truss. The objective is to satisfy upper limits on the acceleration at given points on the truss for a specified excitation. The properties of the dampers are the primary sources of uncertainties. Two optimal designs are obtained from deterministic and probabilistic optimizations; the deterministic approach maximizes safety margins while the probability of failure (i.e. exceeding the acceleration limit) is minimized in the probabilistic approach. The optimizations are performed with genetic algorithms. The predicted probability of failure of the optimum probabilistic design is less than half that of the deterministic optimum. Finally, optimal deterministic and probabilistic designs are compared in the laboratory. Because small differences in failure rates between two designs are not measurable with a reasonable number of tests, we use anti-optimization to identify a design problem that maximizes the contrast in probability of failure between the two approaches. The anti-optimization is also performed with a genetic algorithm. For the problem identified by the anti-optimization, the probability of failure of the optimum probabilistic design is 25 times smaller than that of the deterministic design. The rates of failure are then measured by testing 29 realizations of each optimum design. The results agree well with the predictions and confirm the larger reliability of the probabilistic design. However, the probabilistic optimum is shown to be very sensitive to modelling errors. This sensitivity can be reduced by including the modelling errors as additional uncertainties in the probabilistic formulation. / Ph. D.