The purpose of this poster session is to present normative data and test-retest reliability for slow harmonic acceleration (SHA) and velocity step testing (VST) on rotary chair in healthy individuals.

This thesis investigates potential materials to be used in the rotary sealing industry that provide low power loss and minimize cost. The studied rotary valve utilizes slots that act as timing valves to allow for flow axially, through the seal face, at particular times within a heat pump cycle. This investigation examines various combinations of multiple PTFE materials, plastics, and soft metals that have been proven to provide low friction coefficients. Leakage and wear requirements are stated for the future use of the rotary valve and are used to determine the effectiveness of sealing the fluid while examining the power loss. In conclusion, the study finds the combination of a modified PTFE stationary ring and Aluminum Bronze rotating face to provide the lowest power loss. Numerical analysis was completed to verify the lubrication regime to be partial lubrication and was also used to investigate geometry changes and impact on the power loss.

The aim of this study was to determine the change in working length (∆WL) before and after coronal flaring and after complete rotary instrumentation as a function of canal curvature. One mesiobuccal or mesiolingual canal from each of 43 extracted molars had coronal standardization and access performed. Once the access was completed, canal preparation was accomplished using Gates Glidden drills for coronal flaring and EndoSequence files for rotary instrumentation. WLs were obtained at 3 time points: pre-instrumentation (unflared), mid-instrumentation (flared) and post-instrumentation (concluded). Measurements were made via direct visualization (DV) and the CanalPro apex locator (EM) in triplicate by a single operator with blinding across the time points. Root curvature was measured using Schneider’s technique. The change in working length was assessed using repeated-measures ANCOVA. The direct visualization measurements were statistically larger than the electronic measurements (paired t-test difference = 0.20 mm, SE = 0.037, P < .0001), although a difference this large may not be clinically important. Overall, a greater change in working length was observed in straight canals than in curved canals. This unexpected finding was attributed to the limitations of the study, specifically the confounding factor of root length. This trend was more pronounced when measured electronically than via direct visualization, especially after complete instrumentation than after coronal flaring. The overall change in working length after complete instrumentation was found to be clinically insignificant in this study. A limited amount of change in working length may be expected prior to obturation.

Hard turning of difficult-to-cut materials is an economical method of machining components with high surface quality and mechanical performance. Conventionally in the machining industry, generating a component from raw goods includes a casting or forging process, rough machining, heat treatment to a desired hardness, and then finished-machining through a grinding process. Given the relative disadvantages of grinding, which include high specific energy consumption and low material removal rates, a newer technology has been introduced; hard turning. After the heat treatment of a cast part (generally in a range of 50-65 HRC), hard turning allows for immediate finished-machining. Hard turning reduces the production time, sequence, cost, and energy consumed. In addition, dry machining offsets environmental concerns associated with the use of coolant in grinding operations as well as other common turning operations. Higher specific forces and temperatures in the contact area between the tool and workpiece lead to excessive tool wear. Generated tool wear affects the quality of the machined surface. Therefore, minimizing tool wear and consequently the generated surface quality become the status quo. Adverse effects associated with generated heat at the tool tip can be reduced by using cutting fluid or by continuously providing a fresh cutting edge. The latter method will be applied in this thesis. Rotary tool cutting involves a tool in the form of a disk that rotates about its axis. Different types of rotary tools have been developed, all with similar functional characteristics, however few are commercially available. Rotary tools can be classified as either driven or self-propelled. The former is provided rotational motion by an external source while the latter is rotated by the chip flow over the rake face of the tool. A prototype self-propelled rotary tool (SPRT) for hard turning was developed which provides economical benefits and affordability for the user. It was tested on a turret-type CNC lathe by machining AISI 4140 Steel that was heat treated to 54-56HRC and Grade 5 Titanium (Ti-6Al-4V). Carbide inserts with ISO designation RCMT 09 T3 00 (9.5mm diameter) were used during machining. Both the SPRT rotational speed and the workpiece surface roughness were measured. Also, chips were collected and analyzed for each of the cutting conditions. The same procedure was followed during machining with the same tool which was denied the ability to rotate, therefore simulating a fixed tool with identical cutting conditions. Comparisons were made between tool life, surface roughness, and chip formation for the fixed tool and SPRT. Tool rotational speed was also analyzed for the SPRT. In general, the designed and prototyped SPRT showed very good performance and validated the advantages of self-propelled rotary tools. A typical automotive component that is hard turned from difficult-to-cut materials is a transmission input shaft. These components demand high strength and wear resistance as they couple the vehicle‟s engine power to the transmission and remaining driveline. / UOIT

A mathematical model to simulate the reaction kinetics of dust–carbon composite agglomerates in an RHF was developed. Major chemical, thermal and physical phenomena taking place during RHF treatment were formulated and the corresponding equations were solved to yield the trend of solid composition, temperature and gas composition of the agglomerates. The model calculation results indicate that the pellet reduction is accelerated by the reducing gas from high–volatile reductants if the gas is released after the pellet temperature is sufficiently high for reduction. The reduction of zinc oxide can also be represented using the model by implementing its small particle size caused by the inherent vaporization/re–oxidization process that zinc comes through in a melter. It was demonstrated that the proposed model can be used as an engineering tool to determine the optimum operating conditions for the RHF process to promote recycling a wide range of waste materials.

A mathematical model to simulate the reaction kinetics of dust–carbon composite agglomerates in an RHF was developed. Major chemical, thermal and physical phenomena taking place during RHF treatment were formulated and the corresponding equations were solved to yield the trend of solid composition, temperature and gas composition of the agglomerates. The model calculation results indicate that the pellet reduction is accelerated by the reducing gas from high–volatile reductants if the gas is released after the pellet temperature is sufficiently high for reduction. The reduction of zinc oxide can also be represented using the model by implementing its small particle size caused by the inherent vaporization/re–oxidization process that zinc comes through in a melter. It was demonstrated that the proposed model can be used as an engineering tool to determine the optimum operating conditions for the RHF process to promote recycling a wide range of waste materials.

Nowadays the aviation industry is playing an important role in our daily life, since is the main medium that satisfies the present human needs to reach long distances in the fastest way. But such benefit doesn’t come free of collateral consequences. It is estimated that each year, only the air transport industry produces 628 mega tonnes of CO2. Therefore, urgently actions need to be implemented considering that the current commercial fleet will be doubled by 2050. The research field for more efficient aircraft systems is a very constructive field; where novel ideas can be exploited towards the mitigation of the coming air transport development. In this research the configuration of the Environmental Control System (ECS) has been analysed aiming to reduce its energy consumption for both, fixed-wing and rotary-wing aircraft. This goal is expected to be achieved mainly through the replacement of the main source of power that supplies the ECS, from pneumatic to electric. Differently from the conventional ECS, a new electric-source technology is integrated in the system configuration to compare its effects on the energy consumption. This new technology doesn’t bleed air directly from the engines; instead of that, it takes the air directly from the atmosphere through the implementation of an electric compressor. This new technology has been implemented by Boeing in one of its most recent airplanes, the B787. Towards achieving the main goal, a framework integrated with five steps has been designed. An algorithmic analysis is integrated on the framework. The first step meets the required aircraft characteristics for the analysis. The second step is in charge of meeting the mission profile characteristics where the overall analysis will be carried out. The third step assesses the conventional ECS penalties. The fourth step carries out a complex analysis for the proposed electric ECS model, from its design up to its penalties assessment. The fifth step compares the analysis results for both, the conventional and the electric models. The fourth step of the framework, which analyses the electric ECS, is considered the most critic one; therefore is divided in three main tasks. Firstly, a small parametric study is done to select an optimum configuration. This task is carried out towards meeting the ECS air conditioning requirements of a selected aircraft. Secondly, the cabin temperature and pressurization are simulated to analyse the response of the configured electric ECS for a mission profile. And finally, the fuel penalties are assessed in terms of system weight, drag and fuel due power-off take. To achieve the framework results, a model which receives the name ELENA has been created using the tool Simulink®. This model contains 5 interconnected modules; each one reads a series of inputs to perform calculations and exchange information with other modules.

The goal of the project was to enhance the period of weed growth prior to seeding in order to reduce weed emergence and weed competition after the crop has been planted. Weed growth was stimulated using either light tillage or by applying nitrogen fertilizer early in the spring. Light disturbance significantly increased pre-seed weed emergence while early applied nitrogen did not appear to have an effect. Post seeding weed emergence levels and weed biomass were similar among the light tillage and early nitrogen treatments. Therefore the goal of decreasing weed competition after seeding was not attained. Future research should focus on long-term strategies to reduce weed populations in field rather than seasonal strategies. / October 2006

Plastic  deformation of tubes can be achieved in numerous ways. One of the most useful type is CNC tube bending machines which is used in many industries such as aerospace, automotive, HVAC systems and so on. It is important that all components of system should mate properly after producing and because of this bend shaping requires sensitive operation on each components to ensure regularity of production processes with high quality end-product. Thus, the CNC tube bending industry to become widespread. However it brings some troubleshooting like wrinkling, springback, breakage and ovalisation. This failures depends on geometry of the material such as bending radius, tube thickness and also friction factor between dies and the tube. Effects of all parameters should be examined before generating the theory for a best solution. Therefore, prediction of the required moment for the proper bending process with low cost and shortened production time is needed. All of these requirements can be achieved through a C++ form application program.

The chip formation process in machining is accompanied by heat generation. The heat generated influences both the workpiece physical properties as well as the cutting tool. High temperatures accelerate tool wear and thermal softening which are not desirable because they alter the accuracy of the machined surface and tool life. Many studies have been done to lower the heat generated in cutting. A first approach is to use a cutting fluid but its effectiveness is limited by its ability to penetrate between the tool and the chip. A second approach is to remove the heat generated through a cooling cycle as in interrupted cutting. The idea is either to translate a wide tool to the side as it moves forward relative to the workpiece, which allows the dissipation throughout the body of the tool or to use a cutting edge in the form of a disk that rotates about its principal axis. The latter, known as a rotary tool, provides a rest period for the cutting edge, thus enabling the edge to be cooled and a continuously fresh portion of the edge to be engaged with the workpiece. The rotary tool can be either driven by an external power source or self-propelled. This thesis focuses on the self-propelled rotary tool (SPRT) process for machining of difficult-to-machine material such as bearing steels, where tool life is of particular concern. Since the cutting temperatures are known to influence tool life significantly, the first task in this investigation involved developing a model to analyze heat transfer and temperature distribution in the cutting tool during SPRT turning of the hardened 52100 steel (58 HRC). Both rotary and equivalent fixed tool processes are compared in terms of cutting tool temperatures generated. The model is based on the moving heat source theory of conduction and employs the Finite Element Method (FEM) for its solution. The model is experimentally verified through measurement of the cutting temperature distribution using an Infra-Red imaging camera under different cutting conditions. Predicted and measured temperatures show good overall agreement when they are measured along the cutting edge and measured temperatures are up to 50??ower in rotary tool cutting than in fixed tool cutting under the same conditions.