Human disturbance of avifauna and other wildlife is defined as any intentional or unintentional anthropogenic action that elicits a metabolic or behavioral response. I proposed that the energetic response to disturbance should be reflected as increased existence metabolism (EM). If so, then there must be three behavioral responses to increased EM: increased energy intake compensates for increased EM, habituation reduces increased EM, and dispersal avoids increasing EM altogether. I applied this model to captive and free-ranging nonbreeding sanderlings (Calidris alba). I exposed 24 captive sanderlings to a 5-min disturbance event during each of 10 diurnal hours over two 4-d trials. The metabolizable energy of food ingested was determined for each bird daily. Total body electrical conductivity and body mass were measured during trials to account for energy derived from metabolized body tissues. These combined values suggest that EM was elevated by 7% in response to disturbance during 8% of daylight hours. Caged sanderlings responded to disturbance with alert and attempted escape behaviors; i.e., dispersal. Sanderlings spent more time attempting to escape on the first day of each trial and during the first of 10 disturbance events in a day, suggesting some behavioral habituation. There was evidence of compensatory feeding after the trials, but not during them. Abundance, behavior, and distribution of free-ranging sanderlings were studied at Assateague Island National Seashore, Maryland, during two winters in 1991-93. Increasing pedestrian traffic decreased the probability of sanderling occurrence on 200-m plots by as much as 45%. Average sanderlings ambulated or flushed when pedestrians and vehicles approached within 20 m and 10 m, respectively, and flushed more frequently in response to pedestrians than vehicles. Mean densities were nearly 60% less on disturbed than undisturbed 200-m plots. Sanderling densities were highest on plots with invertebrate prey and no disturbance, and lowest on those with disturbance and no prey. Apparently, higher food availability can partially compensate for the costs of disturbance. Disturbed sanderlings spent 177% more time in maintenance behaviors, 151% more time in flight, and 42% less time roosting than undisturbed sanderlings. On average, undisturbed sanderlings expended 6 kJ-h⁻¹ whereas disturbed sanderlings expended 9 kJ-h⁻¹. More than 90% of the variation in energy expenditure was attributable to time in flight. Although chronic human disturbance can elevate EM in the caged environment, the flush response largely determines the energetic cost of disturbance in free-ranging sanderlings. / Ph. D.

A human factors experiment was conducted to determine the effects of warning sound type, speaker location, and age on the ability to localize the direction of warning sounds in a passenger vehicle. The purpose of these warning sounds is to alert a driver of potential roadway hazards detected by an in-vehicle crash avoidance warning device. Auditory localization of the warning sound was investigated as a means of indicating hazard locations relative to the vehicle. Four dependent variables were measured— response time, decision time, accuracy, and azimuth—to assess the speed and accuracy of localizing six different warning sounds from each of sixteen speaker locations. The six warnings were found to be appropriate for crash avoidance warning applications through a previous study. The localization task was performed in the passenger compartment of a stationary 1995 Ford Taurus sedan. Subjects input their responses through a joystick. The results of the study suggest that the implementation of localized auditory crash avoidance warnings could be beneficial in the timely identification of hazard locations in the vehicle environment. People can quickly localize the general direction of warning sounds (= 1 s to 1.5 s); however, localization effectiveness depends on the proper choice of warning sound and speaker location. Otherwise, potentially serious problems can occur if poor choices are made. The study was successful in identifying sounds and speaker locations that performed best and provides recommendations for speaker placement for each of six potential hazard directions for the vehicle tested. / Master of Science

“An architectural initiation includes today, in my opinion, a strong familiarity with history-a history that is no longer a storehouse of forms or a workshop of styles, but one that simply offers the material for thinking about the evolution of architecture, as well as the way in which architects worked in the past.” - Rafael Moneo The critical placing of new architectural elements against a preexisting context offers an opportunity to uncover both a historical and a physical dimension. The project becomes a kind of seam in a currently undefined urban situation. It is an attempt to amplify the small town structure of Pulaski through a carefully placed civic building typology reconnecting the major town elements of Main Street and Third Street. / Master of Architecture

Nearly 40% of the bridges in the United States are considered deficient and half of the costs needed to repair these bridges is associated with bridge deck deterioration. Chlorides are the primary cause of reinforced concrete deterioration in marine environments and areas of deicing salt usage. The chlorides penetrate the concrete and initiate corrosion of the reinforcing steel. A proven corrosion inhibitor system, the Postrite Post-treatment System, used in reinforced concrete rehabilitation, employs the use of a spray treatment of Postrite (15% calcium nitrite by weight) onto the substrate concrete. The Postrite treatment is followed by a DCI-S (30% calcium nitrite by weight) containing concrete overlay. The structural performance effect of the Postrite post-treatment system used in the resurfaciing of reinforced concrete bridge deck slabs was evaluated in this study. Twelve specimens, two monolithic and ten rehabilitation slabs, were cast. The slabs were tested dynamically for load/deflection analysis. The direct shear and tensile strengths of the overlays were tested and evaluated. Strain gages were used to aid in an overlay to substrate interaction evaluation. The Postrite post-treatment system was determined to have no detrimental effects on the bridge deck slabs performance. The rehabilitation slabs exhibited a smaller deflection than the monolithic under equivalent loadings. The direct shear tests of the overlays exceeded the minimum needed to sustain horizontal shear stresses. The measured direct tensile strengths of the overlays were sufficient to resist delamination which might result from traffic loading or freezing and thawing conditions. The strain gage data indicated that there was partial interaction between the overlay and substrate concretes. / Master of Science

The thermal oxidative stability was evaluated for 7 high oleic acid sunflower (HOSO) and polyunsaturated soybean oil (PUSB) blends ranging from 0.0% to 100.0% of each vegetable oil. Each blend was evaluated in quadruplicate over an eleven day period with 300 minutes of heating at 180°C per day. Thermal oxidative stability was determined by changes in peroxide values (PV), fatty acid and triglyceride composition, and percentage of major volatile products (%MVP). A 2 Way ANOVA, simultaneous confidence intervals, trend analysis, and Paired t-Test, each with a set p value of (0.01) were used for the statistical analysis. The triolein (OOO), trilinolein (LLL), and fatty acid contents were significantly different (p< 0.01) between each blend before and after heating, with the exception of stearic acid levels, which were not significantly different between each blend. Thermal stability increased for the triglycerides and fatty acids as the degree of saturation increased: (Saturated > Monoenic > Polyenic). The addition of HOSO to PUSB increased the thermal oxidative stability of all the blends when compared to the 100% PUSB. The PV and %MVP increased as the levels of OOO decreased and the levels of LLL increased in the blends. The blends with a (1:1) ratio of each vegetable oil experienced a unique breakdown pattern. The monoenic fatty acid levels decreased and the polyenic fatty acid levels increased for this blend only. Overall, blends with 10% to 75% HOSO addition performed equally as well in the thermal oxidative stability testing. / Master of Science

The thesis begins with a discussion of loss of field relaying principles, which is followed by a discussion of real-time playback systems. Loss of excitation protection has been implemented in General Electric’s EX2000 Digital Exciter. Through the use of EMTP, several different system disturbances are simulated. The EMTP files are then played back with the help of a real-time playback system. The signals from the playback system are then fed to the EX2000 and General Electric’s Digital Generator Protection (DGP) System, in order to compare the performances of both systems. The paper concludes by showing that the loss of excitation protection function in the EX2000 works identical to conventional protection systems. / Master of Science

Techniques based on Lyapunov theory for the stability analysis and control of nonlinear systems are developed. In the first part of this work, procedures for determining conditions of guaranteed asymptotic stability are developed for nonlinear, uncontrolled systems. A second order model of an aircraft which is potentially unstable in pitch is used to demonstrate these methods. This approach is then expanded for use with systems of arbitrary order and applied to the investigation of a nonlinear model describing the lateral-directional motion of a departure prone aircraft. These investigations show that concepts based on Lyapunov stability can be used to effectively analyze nonlinear systems. A systematic method of finding an efficient controller is then developed for systems having controls which behave nonlinearly. These control techniques are demonstrated on a generic aircraft which exhibits nonlinear elevator behavior at high angles of attack. Although a conventional controller based on linear theory results in an unstable divergence, a Lyapunov based controller intelligently uses the available elevator power to augment the stability of the aircraft. A Lyapunov controller is then developed for use with the orbital Clohessy-Wiltshire equations of relative motion. When an engine unpredictably fails, this controller automatically accounts for the new conditions and the desired rendezvous is thus, still obtained. These Lyapunov based controllers are shown not only to perform well under highly nonlinear circumstances but to also maintain a high level of efficiency under more linear conditions. / Master of Science

The present work is a detailed study of the parameters that are involved in the characterization of fabric systems. These fabric systems are used as reinforcements in composite structures. Processes such as Resin Transfer Molding and Resin Film Infusion Molding that are used to manufacture composite structures, depend heavily on the responses of these reinforcements for their success. Fabric systems have undergone rapid changes over the years and have reached extremely advanced and complex forms. Near net shape preforms have become popular, and techniques such as multi-axial warp knitting and 3-D braiding are used to accomplish this. Further, the combination of these preforms with manufacturing processes such as Resin Transfer Molding and Resin Film Infusion Molding have resulted in the fabrication of complex composite components. The viability of these techniques for mass production has resulted in wide spread attention over recent years. The problem of estimating the resistance of a given textile preform to the flow of resin or any fluid medium is characterized by its permeability. This quantity is dependent on the pore architecture and is therefore system dependent. The permeability of a preform changes with fiber volume fraction due to the changes in pore architecture. It is therefore critical to understand this quantity apriori, in order to ensure efficient fabrication of composite structures. The complex nature of the pore architecture, makes permeability assessment an extremely difficult issue. Repeatability of test runs can become a difficult task as small inherent changes in the preform, can result in differences in pore structure and therefore result in different permeabilities. This study therefore tries to address this issue by incorporating a special study on the effects of statistics in permeability measurements. High costs of material handled, leads to limited testing and therefore small data bases. It is therefore important to take care while selecting the descriptive population distribution. The Student’s t Test was used in this study to generate 50% confidence bands around the steady-state permeability data obtained on tests run using Type 162 E-glass fabric. The results were then compared with a similar advancing front permeability test. The results were found to be extremely encouraging. The following work also involves the detailed study of compaction behavior of both multi-axial warp knit and braided preforms. Power law regression fit curves were obtained on the data in order to describe the change in fiber volume fraction with respect to applied external pressure, over a range of fiber volume fractions. Since the advent of composites, weak interfacial properties such as delamination and impact resistance have caused considerable concern in the community. Recently, through the thickness reinforcing techniques such as stitching have gained importance as being an inexpensive solution to this apparent problem. The present work involves the study of the effects of stitching density on compaction and permeability. Preforms with four stitching densities were tested along with a similar batch of unstitched preform, and regression curves were fitted to the data obtained. The effects of braiding angle in 2-D, triaxially braided preforms was also studied as a part of trying to understand this ancient yet extremely interesting form textile manufacturing. Effects of thickness in 2-D, triaxially braided preforms was also examined. A small amount of work was also done to study the effects of sizing/finishing on compaction and permeability. Both, 7781, E-glass and AS4 Graphite fabric were tested. / Master of Science

The question of whether the mafic and ultramafic rocks of the central Virginia Blue Ridge are part of a Late Proterozoic to Ordovician ophiolite-bearing sequence or part of an intrusive-extrusive sequence related to the Late Proterozoic Iapetan rifting has major implications for Appalachian tectonic models. Current models consider most of the Blue Ridge cover sequence to be ophiolitic mélange that was obducted onto Laurentia, thus implying a suture or terrane boundary is associated with the rocks. Detailed field mapping and petrography of three typical mafic-ultramafic complexes in the central Virginia Blue Ridge (the Catfish, Flat Creek, and Schuyler complexes) indicate that these bodies do not show characteristics that resemble ophiolites. The three complexes are broadly conformable with stratigraphic layering, and the Lynchburg Group host strata form a continuous and conformable stratigraphic sequence unbroken by faults and without evidence of mélange. Contacts between the mafic-ultramafic bodies and the host rocks are sharp and show no strong evidence for faulting or other disturbances. Internal contact relations and the presence of autoliths indicate that these bodies were derived from multiple injection of a fractionating basaltic magma. The characteristics of the Catfish, Flat Creek, and Schuyler complexes confirm that the mafic-ultramafic association is an intrusive sequence rocks intimately related to the Late Proterozoic Iapetan rifting. The rocks are not part of a Late Proterozoic to Ordovician ophiolite sequence or mélange. Therefore, there are no sutures or terrane boundaries in the central Virginia Blue Ridge. / Master of Science

The analytical models for the design of automatic guided vehicle systems (AGVs) available in the literature are limited to the computations of the fleet size and the design of the guide path layout. Another major design factor which affects the performance of an AGV system is the locations and the dimensions of the control zones. The control zones facilitate congestion free flow of AGVs along the guide path. A proper design of the control zones is extremely important for the functioning of the AGV system. When the effects of the control zones are included in an analytical model, its solution procedure becomes complicated and difficult to be solved. This is due to the various interactions between the work stations and AGVs caused by the control systems. In this thesis, Petri net theory is introduced as an alternative method for the modeling of AGV systems. It is a graph theoretic tool which can easily capture synchronization and resource sharing situations which are common in AGV systems. Further, well developed mathematical procedures are available to analyze them. A systematic Petri net modeling procedure for AGV systems using sub nets is provided in this thesis. The Petri net model is used to compute the fleet size and the control zone dimensions of the AGV system. / Master of Science