Literatura científica selecionada sobre o tema "LD5655.V855 1996.F559"

Great improvements are continuously being made in the solid free form fabrication (SFF) industry in terms of processes and materials. Fully functional parts are being created directly with little, if any, finishing. Parts are being directly fabricated with engineering materials such as ceramics and metals. This thesis aims to facilitate a substantial advance in rapid prototyping capabilities, namely that of fabricating parts with continuously heterogeneous material compositions. Because SFF is an additive building process, building parts layer-by-layer or even point-by-point, adjusting material composition throughout the entire part, in all three dimensions, is feasible. The use of fine powders as its build material provides the potential for the Selective Laser Sintering (SLS), ThreeDimensional Printing (3DP), and Freeform Powder Molding (FPM) processes to be altered to create continuously heterogeneous material composition. The current roller distribution system needs to be replaced with a new means of delivering the powder that facilitates selective heterogeneous material compositions. This thesis explores a dense phase pneumatic conveying system that has the potential to deliver the powder in a controlled manner and allow for adjustment of material composition throughout the layer.

Master of Science

I've titled my thesis, "Intrinsics" because my architectural design is an attempt to respond to what is inherent in the materials, in the way materials are joined, in the flow of forces through the structure, in the site and surroundings, and in the human nature of a person using the building type I'm designing. This is a tectonic approach, so my thesis is also "An Exploration of Tectonic Expression" with a Montessori school as a project vehicle. The site is next to the Roanoke Public Library in Elmwood Park in Roanoke, Virginia. The primary materials are glue-laminated wood beams and arches, metal connectors, and reinforced concrete walls. I explored what can happen if each layer of a glue-laminated member is allowed to act independently, separating from the girder in appropriate places to recombine into a new whole. The monolith transforms into a pattern of parts.
Master of Architecture

Experimental and analytic investigations were performed to examine the influences of wall height, backfill behavior, and compaction on the magnitudes of backfill loads on rigid retaining walls. Measurements of lateral and vertical backfill loads were made during tests using the Virginia Tech instrumented retaining wall facility. The tests were performed with two soils, moist Yatesville silty sand and dry Light Castle sand. Two hand-operated compactors, a vibrating plate compactor and a rammer compactor, were used to compact the backfill. The backfill height was 6.5 feet in all of the tests. Analyses of backfill loads were made using a compaction- induced lateral earth pressure theory and a vertical shear force theory. The compaction-induced lateral earth pressure theory was revised from a previous theory. The revisions improved the accuracy with which the theory models the hysteretic stress behavior of the backfill during compaction. The theory was also extended to include the pore pressure response of moist backfill in a rational manner. A vertical shear force theory was also developed during this research. The theory is based on consideration of backfill compressibility and mobilization of interface shear strength at the contact between the backfill and the wall. The theory provides a useful basis for understanding how wall height, backfill compressibility, wall-backfill interface behavior, and compaction-induced lateral pressures affect the vertical shear forces on rigid walls. Studies were also made to investigate the cause of erratic pressure cell readings. An important cause of drift in pressure cell readings was found to be moisture changes in the concrete in which the pressure cells were mounted. It was found that this problem could be mitigated by applying a water-seal treatment to the face of the wall. Both the vibrating plate compactor and the rammer compactor were instrumented to measure dynamic forces and energy transfer during compaction. The force applied by the vibrating plate compactor was about one-quarter of the manufacturer’s rated force. The force applied by the rammer compactor was about twice the manufacturer’s rated force. The transferred energy measurements provided a basis for relating laboratory and field compaction procedures.
Ph. D.

The purpose of the current study was to investigate whether the separate contributors to procedural and distributive justice also affected the other form of justice. Previous research investigating these cross over effects of justice contributors had not examined inputs in addition to outcomes and procedures, and had typically assumed outcome level to be equivalent to the equitableness of outcomes. Subjects were 120 undergraduate psychology students. Outcomes, inputs and procedures were manipulated in a laboratory experiment in order to assess their independent and combined effects on distributive and procedural justice perceptions. In contrast to past research, the current study found a weak and inconsistent effect of procedures on distributive justice perceptions. Outcome level had a strong effect on both procedural and distributive justice perceptions. In addition, outcome fairness was found to effect procedural justice perceptions. When procedures were fair, the equitableness of outcomes influenced distributive justice ratings. When procedures were unfair, however, the equitableness of outcomes did not influence distributive justice judgements. Implications for procedural justice conceptualizations, equity theory and organizations are discussed.
Ph. D.

The purposes of this study were to (a) identify training provided by North Carolina school systems for its Administrative Placement Committee/Specific Learning Disabilities (APC/SLD) eligibility committee members, and (b) assess the perceived training needs of APC/SLD eligibility committee members. The sample consisted of 77 special education program administrators, 58 teachers (special education and regular education), 56 pupil support personnel and 63 school administrators. Descriptive data were gathered using two questionnaires. The special education program administrator survey contained items regarding the composition and selection criteria of the APC/SLD eligibility committee and system-wide training provided. In addition, the survey made inquiry regarding problems and concerns that committee members have expressed regarding their understanding and implementation of SLD requirements and the efficiency or effectiveness of committee meetings. The eligibility committee survey included items regarding job title, SLD criteria/requirements, information crucial to eligibility decisions, structure of eligibility meetings, group dynamics, and training needed for effective decisions regarding eligibility and placement of students in programs for the learning disabled. The major conclusions drawn from this study were that (1) training is being conducted in the school systems regarding the regulations and procedures for determining a specific learning disability; (2) that there is a definite need for training to be conducted with the eligibility teams on all aspects of making effective eligibility decisions; and (3) there is little difference among the training needs of teachers, support personnel and administrators.
Ed. D.