There has been a phenomenal growth in distance education since it's early days as correspondence study. Computers and the tools that go along with them, help to bridge the gap between physically separated people. Computers allow for resource sharing, decentralization, and limitless opportunities for instantaneous communication and transfer of information around the world. A variation of the traditional distance learner is the on-line learner. The on-line learner is a student on or near campus who chooses to take a class on-line versus the traditional classroom method. Questions are generating regarding why these students choose to take these on-line courses when they have they have access to the physical classroom. Since these students are familiar with an on-line setting, questions are also generating regarding the availability of on-line services. The participants included in this study were on-line learners enrolled in 13 totally on-line classes offered at a large, public, research university located in a mid-Atlantic state. The purpose of this study was to examine what motivates students to take on-line courses and to assess their interest in receiving other academic and student services on-line. Data were collected through a survey designed specifically for this study. / Master of Arts

Polymer additives exemplify many classes of compounds which possess a wide variety of chemical (i.e., phenols, amides, esters) and physical (i.e., volatility, solubility) properties. They are incorporated into polyolefins and other such polymeric materials for a number reasons: (a) to prevent degradation by ultraviolet light, heat, and oxygen; (b) to aid in the processing of the polymer; and (c) to modify the physical properties of the polymer. Since the purity and amount of additive can affect polymer properties, it is very important to characterize and quantify additives in polymer products. Traditional liquid solvent/polymer extraction methods, which involve dissolution/precipitation, are time-consuming, uneconomical, and the recoveries are significantly lower than 90%. In recent years, analysis with supercritical fluids (SFs) has emerged as an alternative analytical technique because SFs afford higher diffusivity and lower viscosity. In this research, an on-line Supercritical Fluid Extraction (SFE)/Supercritical Fluid Chromatography (SFC) system was assembled to provide efficient extraction and separation of polymer additives with quantitative results. The effects of various SFE/SFC parameters, such as trapping temperature, injection temperature, extraction pressure and temperature, dynamic extraction time, and fluid flow rate on extraction and separation efficiencies of different additive standards (i.e., BHT, BHEB, Isonox 129, Irganox 1076 and Irganox 1010) were investigated. Optimized conditions were employed to quantitatively extract additives from LDPE. Identification of additives was performed by comparing the retention time with each additive standard. Results obtained from on-line SFE/SFC were compared to results from off-line SFE/High Performance Liquid Chromatography (HPLC) and off-line Enhanced Solvent Extraction (ESE)/HPLC. / Master of Science

Escape from internet

Underground Residential Distribution (URD) power cables are aged due to electrical, thermal, mechanical, and environmental stresses during their service. The recent dielectric conditions of the cables are of much interest for utilities. The existing offline diagnostic method requires forceful disconnection of the URD cable for maintenance. Online recording and Fast Fourier Transform analysis of intentionally created transients in URD is one of the promising method to assess the current condition of the cable. For the bigger goal of developing an online power cable condition assessment, the measurement techniques which are required to be implemented has to be evaluated. In order for implementing the online measurement system, the requirements of the measurement system have to be identified at first. URD system model was simulated using Electro Magnetic Transient Program to identify the characteristics of induced transients. A list of requirements of the measurement system was created based on the simulation results

The uncountable number of tools for the creation of synthetic terrains poses as a challenge for simulation interoperability. The permutations of tools, elevation maps, and software settings leads to combinations of poorly correlated virtual terrains. An important issue in distributed simulations is the lack of line-of-sight correlation. For example, in military networked simulations, consistent intervisibility between simulated entities is crucial for a fair-fight, especially when simulations include direct-fire weapons. The literature review presented in the Chapter Two discusses a multitude of interoperability issues caused by discrepant terrain representations and rendering engines noncompliant to any standard image generation process. Furthermore, the literature review discusses past research that strived for measuring (or mitigating) the correlation issues between terrain databases. Based on previous research, this thesis proposes a methodology for analysis of line-of-sight correlation between a pair of terrain databases. All the mathematical theory involved in the methodology is discussed in the Chapter Three. In addition, this thesis proposes a new method for measuring the roughness of a visual terrain database. This method takes into account the 3D dispersion of the vectors normal to the polygons in the terrain's mesh. Because the vectors normal to the polygons are conveniently stored in most visual databases, the roughness calculation suggested here is fast and does not require sampling the terrain's elevation. In order to demonstrate the proposed method, twin terrain databases and a tool were created as part of this thesis. The goal of this tool is to extract data from the terrain databases for statistical analysis. The tool is open source and its source code is provided with this thesis. The Chapter Four includes an example of statistical analysis using an open source statistic software. The line-of-sight correlation analysis discussed here includes the terrain's geometry only (terrain's culture is not addressed). Human factors were not taken into consideration.

Traditional viewshed analyses distinguish between those areas which can be seen from a given observation point and those which cannot be seen. Given a surface digital elevation model (DEM) and observer properties (location and height), the algorithm computes whether or not each target cell is within the observer's line-of-sight. Just as significant and robust (although yet not commercially available) would be a tool that could search local neighborhoods of the observer to determine if different tower placements could achieve significantly improved viewsheds. This thesis customizes the popular ArcGIS software to demonstrate the implementation of such a tool. The use of different sampling methods specifies locations to site observation points throughout the Virginia Tech central campus, characterized by having large open areas in an otherwise urban environment. Analysis of the viewsheds calculated both before and after applying the optimization tool determined the amount of coverage gained by moving the observer short distances across the ground. In large open areas (Drillfield, parking lots), optimization achieved minimal gain, however in areas near buildings, significant increases in visible area were possible by moving the observer to the top of a nearby building. This research rejects the common belief that the best location for an observer or transmitter in open areas is always at the highest elevation point. However, in settings with tremendous vertical differences over small horizontal distances (ground to roof), the belief is justified. / Master of Science

This thesis is concerned with the art and act of sketching existing architecture. "Drawing an Education" refers to both educating the line by the practice and habit of drawing and to allowing the line to be the educator by drawing from buildings and places, disclosing relationships, structure and meaning. "Influence and evidence" refers to the influences that affect the process and the evidence as exhibited in a finely tuned intuition. This thesis is arranged as a three-part inquiry: • Drawing: how sketching facilitates an intimate connection between the architect and the place, the effect on the collective reality and cultural transmission, and sketching in relation to the photograph, both as a device and as a source; • Influences: how six major influences impact the drawing process, each investigated individually and in relationship to one another, both in an historical as well as a poetic context - eye and perception; interpretation; representation; hand and discipline; media and format; and the line itself; • Implications: how an architect's drawing an education through sketching the built environment is evidenced as a developed intuition and imagination. It is intended that the reader will have a greater awareness of the process of architectural sketching and be encouraged to draw more, perceive more, and understand more as he sketches along the way, as well as when he embarks on his own Grand Tour. / Master of Architecture

<p> An examination of the Man-Machine interface as found in the Designers Computer aided optimization techniques OPTIPAC/OPTISEP is first presented. Several guidelines for the implementation of an improved interface using a time-shared computer system are then described. </p> <p> A graphic means of assessing the behaviour of an optimization problem's objective function and the various constraints acting upon it is then outlined in the form of the subroutine OPTPLOT. Several sample plots involving the optimization of system reliability are then generated using a conversational programming technique.</p> <p> The same programming technique is then applied to the OPTISEP series of subroutines and a demonstration of the system using the previous sample problem is included.</p> <p> A hypothetical, but truly interactive system is then postulated and the possibilities for its implementation at McMaster with the facilities presently available are outlined. </p> / Thesis / Master of Engineering (MEngr)

<p> The thesis contains an experimental verification of a paper by D. G. Huber dealing with a solution to the problem of the irrotational motion of two fluid strata towards a line sink. Friction was assumed negligible in the theoretical analysis and, as a result, the experimental values deviated somewhat from the theoretical expectations. The largest deviation occurred at the point of incipient drawdown where the theoretical and experimental values of the Froude number differed by 48%. The trends obtained in the experiment verify the theoretical solution. The effect of viscosity at the point of incipient drawdown for two different interface height to width ratios was determined.</p> <p> The work of Harleman et al. in submerged sluice control was extended and showed that the Froude number of the lower layer at the point of incipient drawdown with high rates of flow was much larger than expected. The reason for the change was explained using the Khafagi-Hammad relationships.</p> / Thesis / Master of Engineering (MEngr)

LINE-1 retrotransposons, also known as "jumping genes", are repetitive sequences capable of copying, pasting, and reinserting themselves into the genome. These events were documented at high frequency in various types of cancers, including colorectal cancer (CRC). Furthermore, the expression of proteins encoded by these elements, such as L1ORF1p, has been linked to cancer aggressiveness, stemness, and lower patient survival rates. Colorectal cancer stem cells (CCSC), constitute a small subset of cells endowed with pluripotency and self-renewal abilities. They play roles in tumorigenesis, cancer aggressiveness, drug resistance, cancer recurrence, and metastasis. Conventional chemotherapeutics primarily target bulk tumor cells and tend to spare cancer stem cell populations. Consequently, targeting CCSC is expected to significantly increase complete remission and survival rates in CRC patients. Here, I have characterized specific aspects of a novel repurposed drug that effectively targets CCSC, reactivates the expression of transposable elements and, consequently, triggers an innate immune response. Further, I tested an in silico drug screening approach to identify compounds with high predicted affinity for the RNA binding domains of L1ORF1p, a key protein for the LINE1 retrotransposition event to occur, from a virtual drug library. Two lead compounds, both FDA-approved drugs, were identified and evaluated for their capacity to block L1ORF1p nuclear translocation, a needed step to complete the LINE1 lifecycle, as well as their capacity to decrease LINE-1 retrotransposition levels. In addition, I established a protocol for the isolation, culture, propagation, and cryopreservation of patient-derived normal colonic organoids. This protocol is crucial to the establishment of a colonic organoid biobank, representing a powerful resource to assess cancer-selective toxicity of putative CCSC-targeting compounds. Together, this thesis emphasizes the importance of transposable elements in CRC and contributes to the establishment of a gold standard ex vivo disease-modeling system for the discovery of new therapeutic agents.