This thesis presents a review of the theory of evaporation of pure substances with respect to kinetic and mechanistic models. These concepts are applied to multi-component evaporation and a model for the evaporation of solute atoms from a solvent is postulated. The evaporation experiments were performed on Fe 1% Mn melts at a constant pressure of approximately 10 microns over a temperature range of 1320° to 1810°C. The correlation between the experimental results and the expected theoretical results is discussed thoroughly in terms of surface control and diffusion control. / Thesis / Master of Engineering (ME)

As organizations struggle with processing vast amounts of information, outsourcing sensitive data to third parties becomes a necessity. Various cryptographic techniques are used in outsourced database systems to ensure data privacy while allowing for efficient querying. This thesis proposes a definition and components of a new secure and efficient outsourced database system, which answers various types of queries, with different privacy guarantees in different security models. This work starts with the survey of five order-preserving and order-revealing encryption schemes that can be used directly in many database indices, such as the B+ tree, and five range query protocols with various tradeoffs in terms of security and efficiency. The survey systematizes the state-of-the-art range query solutions in a snapshot adversary setting and offers some non-obvious observations regarding the efficiency of the constructions. The thesis then proceeds with Epsolute - an efficient range query engine in a persistent adversary model. In Epsolute, security is achieved in a setting with a much stronger adversary where she can continuously observe everything on the server, and leaking even the result size can enable a reconstruction attack. Epsolute proposes a definition, construction, analysis, and experimental evaluation of a system that provably hides both access pattern and communication volume while remaining efficient. The dissertation concludes with k-anon - a secure similarity search engine in a snapshot adversary model. The work presents a construction in which the security of kNN queries is achieved similarly to OPE / ORE solutions - encrypting the input with an approximate Distance Comparison Preserving Encryption scheme so that the inputs, the points in a hyperspace, are perturbed, but the query algorithm still produces accurate results. Analyzing the solution, we run a series of experiments to observe the tradeoff between search accuracy and attack effectiveness. We use TREC datasets and queries for the search, and track the rank quality metrics such as MRR and nDCG. For the attacks, we build an LSTM model that trains on the correlation between a sentence and its embedding and then predicts words from the embedding. We conclude on viability and practicality of the solution.

This dissertation presents an automated detection algorithm that identifies severe external defects on the surfaces of barked hardwood logs and stems. The defects detected are at least 0.5 inch in height and at least 3 inches in diameter, which are severe, medium to large in size, and have external surface rises. Hundreds of real log defect samples were measured, photographed, and categorized to summarize the main defect features and to build a defect knowledge base. Three-dimensional laser-scanned range data capture the external log shapes and portray bark pattern, defective knobs, and depressions. The log data are extremely noisy, have missing data, and include severe outliers induced by loose bark that dangles from the log trunk. Because the circle model is nonlinear and presents both additive and non-additive errors, a new robust generalized M-estimator has been developed that is different from the ones proposed in the statistical literature for linear regression. Circle fitting is performed by standardizing the residuals via scale estimates calculated by means of projection statistics and incorporated in the Huber objective function to bound the influence of the outliers in the estimates. The projection statistics are based on 2-D radial-vector coordinates instead of the row vectors of the Jacobian matrix as proposed in the statistical literature dealing with linear regression. This approach proves effective in that it makes the GM-estimator to be influence bounded and thereby, robust against outliers. Severe defects are identified through the analysis of 3-D log data using decision rules obtained from analyzing the knowledge base. Contour curves are generated from radial distances, which are determined by robust 2-D circle fitting to the log-data cross sections. The algorithm detected 63 from a total of 68 severe defects. There were 10 non-defective regions falsely identified as defects. When these were calculated as areas, the algorithm locates 97.6% of the defect area, and falsely identifies 1.5% of the total clear area as defective. / Ph. D.

According to the predominant image, applied science is a linear, sequential process, the application of science. First scientists or applied scientists develop knowledge that satisfies the epistemic criteria of science, and applied scientists then find ways to use this certified knowledge to solve society's problems. There is, therefore, a sharp distinction between epistemic or scientific criteria and social criteria. The historical development of the applied ecological discipline called range science or range management demonstrates instead that applied science is a simultaneous process. Range science developed at a time when America increasingly looked to science to solve social, political, and economic problems in the hope that science's ability to predict could provide the basis for organization and rational management. The institutionalization of range science industrialized ranching. Ranchers appealed to a variety of traditional American values in response to this industrialization, but in the new context surrounding ranching those values had become illegitimate. From the outset, range science acquired a dual orientation toward both the epistemic criteria of science and the social criteria of society. That dual orientation introduced a tension into range science because it was not obvious how range scientists should satisfy both sets of criteria simultaneously. Researchers in different institutional contexts developed distinct resolutions to that tension. The most significant difference between the institutions were their political objectives and a difference in the power relations between range researchers and their audiences. Those institutional contexts defined the social criteria and provided the background to judge the acceptability of particular resolutions of the tension, in the process providing the motivation and justification for range science. Nevertheless, range science was not just politics by another means because range scientists also satisfied the epistemic criteria of science. The distinction between epistemic and social criteria therefore did not exist in the historical development of range science because range scientists simultaneously satisfied the epistemic criteria of science and the social criteria that flowed from different political objectives and different power relations between researchers and ranchers. / Ph. D.

I addressed the effects of landscape characteristics on ruffed grouse (Bonasa umbellus) home range size and movement, and examined grouse selection for specific landscape characteristics and cover types. Grouse home ranges and movement patterns derived from telemetry data gathered from fall 1996 through fall 1998 were overlaid onto a GIS database of Clinch Mtn. Wildlife Management Area, VA. This database was developed from GPS data and LANDSAT thematic mapping imagery (30 m pixel scale) and was composed of 22 cover types. Landscape metrics were calculated using FRAGSTATS/ARC, and multiple regression was used to relate changes in home range size and movement to these metrics. I used Wilcoxon signed-rank tests to compare the values of landscape metrics calculated for each home range to those calculated for the area encompassed by the home range plus a surrounding 300 m buffer. I used Wilcoxon rank-sum tests to compare the values of landscape metrics for the home ranges to the metrics calculated for 50 33 ha random plots. I used compositional analysis to test for preferential use of cover types. I developed 2 regression models (P < 0.01) relating changes in home range size to landscape characteristics, 1 model (P = 0.09) relating the distance between seasonal home range centers to landscape characteristics, and 1 model (P = 0.03) relating average daily movement to landscape characteristics. Grouse home range size increased as patch shape became more irregular and patch size and the number of different cover types per hectare increased, and decreased as the amount of high contrast edge in the landscape increased. The distance between seasonal home range centers increased as Shannon's diversity index and the average distance between patches of similar cover types increased, and decreased as the amount of high contrast edge increased. Average daily movement increased as the average distance between patches of the same cover type increased and as the percent cover of a full (~75%) rhododendron and/or laurel understory within a grouse's home range increased, and decreased as the amount of high contrast edge in a bird's home range increased. Ruffed grouse were selecting areas with high densities of smaller than average patches that were of uniform size and regular shape and contained higher than average amounts of high contrast edge. Areas containing a greater diversity of cover types than what was available in the study area also were preferred. Within these areas, clearcuts and mesic deciduous stands with a rhododendron/laurel understory were the most preferred cover types. Creating and maintaining a landscape with high densities of small patches that are of uniform size and regular (square) shape would provide the highest quality ruffed grouse habitat in this region. Several of these patches should be early successional cover to provide an abundance of high contrast edge. Rhododendron and/or laurel thickets also may be beneficial as supplemental winter cover, and mesic stands of mature hardwoods should be well interspersed with these cover types to provide supplemental food sources. / Master of Science

The Range Limited Antenna (RLA) has the ability to track and pin-point RF devices operating within a certain accepted range. Using two antenna arrays, each made up of several elements, direction-finding algorithms such as MUSIC and Modified Root Pisarenko (MRP) are used to estimate the angles of arrival of incoming signals. Using the estimated angles of arrival, a range estimation algorithm is used to estimate the distance of the emitter from the antenna array. The aim of this thesis is to check the sensitivity of the range estimation and to form a statistical analysis for such conditions. Conditions of error are introduced into the system and several extensive Monte Carlo simulations are run for both MUSIC and MRP. Upon simulating physical errors in the antenna set-up, it is realized that the range estimation algorithm is sensitive to the slightest of phase shift differences, cable loss differences, mixer mismatches, and antenna mismatches. / Master of Science

Articular cartilage is a material with the appearance of simplicity and uniformity, but the chemical and biological structure of this material is very complex and not yet known in every detail. Our knowledge of cartilage wear behavior is limited and needs to be enlarged. Knowledge in this area could be important for the prevention and treatment of degenerative joint diseases. Within the framework of this thesis. a literature search focused on the key words joint lubrication and cartilage wear was conducted. The result of this search was that almost all studies and experiments which have been carried out to investigate tribilogical processes in synovial joints focused on friction behavior. Only a few tests dealing with cartilage wear were conducted. Most of the cartilage wear studies were carried out under exaggerated conditions which might change the wear mechanisms. Two studies were undertaken under conditions close to normal conditions occurring in natural joints; one in entire joints with a pendulum device, the other one with a cartilage-on-cartilage test system. The test devices used in these tests offered no or limited opportunities for the variation of the test parameters. Test parameters are, for example, the type of motion, applied load, velocity, variation of the velocity during each cycle, type of specimen, and test fluid composition. In consideration of the findings of the literature search, it was decided to design a new test device providing the capability of measuring friction, wear, and displacement due to wear and/or cartilage deformation. Furthermore, the new test device for cartilage wear studies, allows the variation of the above mentioned test parameters. / Master of Science

This study focuses on the design and implementation of a humanoid robot for disaster response. In particular, this thesis investigates the lower body design in detail with the upper body discussed at a higher level. The Tactical Hazardous Operations Robot (THOR) was designed to compete in the DARPA Robotics Challenge where it needs to complete tasks based on first-responder operations. These tasks, ranging from traversing rough terrain through driving a utility vehicle, suggest a versatile platform in a human sized form factor. A physical experiment of the proposed tasks generated a set of joint range of motions (RoM). Desired limb lengths were determined by comparing existing robots, the test subject in the experiment of proposed tasks, and an average human. Simulations using the desired RoM and limb lengths were used to calculate baseline joint torques. Based on the generated design constraints, THOR is a 34 degree of freedom humanoid that stands 1.78 [m] tall and weighs 65 [kg]. The 12 lower body joints are driven by series elastic linear actuators with multiple joints actuated in parallel. The parallel actuation mimics the human body, where multiple muscles pull on the same joint cooperatively. The legs retain high joint torques throughout their large RoM with some joints achieving torques as high as 289 [Nm]. The upper body uses traditional rotary actuators to drive the waist, arms, and head. The proprioceptive sensor selection was influenced by past experience on humanoid platforms, and perception sensors were selected to match the competition. / Master of Science

Hemlock woolly adelgid, Adelges tsugae Annand, is an invasive pest threatening eastern (Tsuga canadensis (L.) Carrière) and Carolina hemlock (T. caroliniana Englem.) forests in the eastern US. A new predator, Laricobius osakensis Montgomery and Shiyake, has been found in association with A. tsugae in Japan. Laricobius osakensis was evaluated in a series of pre-release studies to assess its potential as a biological control agent for A. tsugae. Host-range studies indicated that L. osakensis is a specific predator that feeds predominantly and reproduces only on A. tsugae. The functional response "prey consumption changes in response to changes in prey density" was similar for both L. osakensis and Laricobius nigrinus Fender adults. However, L. osakensis had a higher numerical response"changes in oviposition in response to changes in prey density"than L. nigrinus. Laricobius osakensis larvae had a higher functional response than L. nigrinus larvae. Laricobius osakensis\' higher numerical and functional response indicates that this species can potentially be more effective than L. nigrinus. In the evaluation of L. osakensis in sleeve cages in the field from December to April high rates of adult survival, feeding, and reproduction were found. A pair of predators in a cage killed on average five adelgids/day. Peak oviposition occurred in March and April. Larvae from eggs placed in the cages reached maturity in 28-50 days, depending on the season, and only 6.7 % died before reaching maturity. Laricobius osakensis was able to survive, feed, develop, and reproduce in USDA cold-hardiness zones 5b and 6a of southwest Virginia. Behavior of L. osakensis and L. nigrinus was qualitatively similar but varied quantitatively. Laricobius osakensis was more active and had a lower association with T. canadensis. Interactions between species were minimal and not detrimental to either. Intrasexual copulation attempts were observed between males and to a lesser extent between females; however, intrasexual interactions were less frequent than intersexual interactions between the two species. Otherwise activity, including oviposition, was not altered by the presence of the other species. These studies indicate that L. osakensis has the potential to be a valuable addition to the natural enemies complex against A. tsugae. / Ph. D.

All species on Earth occupy limited geographic space. More than a century of observational, experimental, and theoretical work investigating the factors that drive species distributions have demonstrated the importance of the interactions between abiotic, biotic, and demographic factors in determining why species are found where they are. However, it is still unclear when and where these factors interact to set species range limits. Filling the existing knowledge gaps is imperative for the accurate predictions of how species will respond to global change, and particularly for invasive species, many of which are expected to benefit from global change. Here, I sought to investigate the mechanisms that enable, as well as limit, the range expansion of the globally invasive plant Sorghum halepense (L.) Pers. (Johnsongrass). I performed a series of field and laboratory experiments to study population and range dynamics throughout Johnsongrass's North American distribution, and test for the effects of climate, local habitat, and competition on multiple functional traits. I found Johnsongrass consistently demonstrated impressive performance across varying environments, often growing more than 3 m tall, producing hundreds of flowering culms within a single growing season, and maintaining positive population growth rates, even under intense competition with resident weeds. I also found evidence that seed germination has adapted to varying climates encountered during Johnsongrass's range expansion resulting in a shift in the germination temperature niche from warmer to cooler as Johnsongrass spread from warmer climates in the south to more temperate climates in higher latitudes. This shift in the germination temperature niche may have been an important contributing factor in the range expansion of Johnsongrass by enabling the optimization of seed germination in varying climates. On the other hand, results from a field study suggested a possible trade-off between flowering time and growth in populations originating from the range periphery (i.e., range boundary) which may be limiting, or slowing, continued range expansion of Johnsongrass. Together, the outcomes of this work contribute to our understanding of the factors involved in the distribution of species, which is a fundamental goal of Ecology, and essential to accurately predict how invasive species will respond to global change. / Doctor of Philosophy / Invasive species threaten our natural ecosystems, our agricultural systems, and even our infrastructure, and we spend billions of dollars each year attempting to control them and reduce their negative impacts. Climate change, habitat destruction, and other forms of global change, will benefit many of these species, magnifying their impacts and promoting their invasion into new territories. Because of the damaging effects of invasive species, and the costs to control them, it is imperative that we are able to predict how they will respond to global change so that we can improve plans to reduce their impact and spread. First, we need to understand the processes that promote their invasion across large swaths of land. Just as importantly, we must study the processes that prevent their invasion of certain areas. Here, I investigated some of the processes that have facilitated, as well as hampered, the spread of the invasive plant Johnsongrass. For this work, I used Johnsongrass plants originating from different habitats, including regions where Johnsongrass is highly invasive and those where Johnsongrass is very rare. I found Johnsongrass originating from regions where it is highly invasive were able to grow very large and produce thousands of seeds that were able to germinate under a range of conditions. These traits may have contributed to the invasion success of this species. However, I found a different pattern for plants that originated from regions where Johnsongrass is rare. These plants reached reproductive age earlier and grew smaller across all environmental conditions, potentially due to the less hospitable climates of these range edges. These findings allow us to project into future climate change scenarios, because it is likely that, as temperatures warm, invasive species will be able to invade new regions, where they will impact the work of conservationists, natural resource professionals, agricultural produces, and other land managers.