This study was designed to collect data that would provide evidence as to what students' expectations of the environment were along with whether these expectations were actually being experienced by students living in the substance-free environment. A systematic sample of 139 students were surveyed who lived in the Students Uniting to Remain Free (SURF) substance-free living environment at Ball State University during the Fall semester of 2001 academic year. Data collection consisted of a survey instrument that had eight three-part questions, 10 demographic characteristic questions, and six student involvement questions.The data revealed that new and returning students living in the SURF hall were very satisfied with their residential experience. The majority of their expectations matched the majority of their experiences. Statistically significant differences between the expectations of new and returning students existed with the following variables: drinking and using drugs outside of the SURF hall, expecting that they would not have to deal with noise and disruptions caused by alcohol usage, living with students who had similar religious ideals and values, expecting the SURF hall to be a quiet study area and expecting and experiencing wellness and healthy lifestyle programs.The growing interest in substance-free housing environments is an area that many Chief Housing Officers and Student Affairs Administrators may want to consider investing more time researching in addition to allocating additional institutional resources in the creation of increased levels of this living environment option. Current expansion of this lifestyle option on campuses across the nation may dictate that for institutions to stay competitive and to meet the needs of the various populations living on their campuses the offering of this lifestyle option may need to increase. Additional research into the academic benefits and long-term retention benefits may be necessary for the development of new programs. / Department of Educational Leadership

This Master‘s thesis deals with the construction design of the ball screw shaft supports. Designed supports will serve to increase stability of rotating ball screws. In the introduction detailed description of the ball screws is presented including description of the individual parameters of the ball screw. Next part includes parameters of different ball screw properties and design of individual supports with description and design calculations of individual parts of the supports. Concepts of the supports will be designed in compliance with the ball screw product series of the KSK Precise Motion a.s. company.

No description available.

This research project investigates a new technique to efficiently mix crystalline solid additives with polymers by gentle ball milling with steel balls in the presence of carbon dioxide (C02) at 17 to 30°C and 1300 to 2500 psig. As the ball milling system is agitated, the steel balls transfer mechanical energy to the fluoropolymer and additive thereby converting them to powders. C02 is added into the chamber to expand the polymer and make it amenable to impregnation by the additive. At the end of the mixing process, a free flowing powder is produced consisting of the additive coated with fluoropolymer. The additives were extracted from the powders and intrinsic viscosity measurements were done on the remnant fluoropolymer. Viscosity studies showed that the virgin and post-ball milled fluoropolymers had similar intrinsic viscosities, hence similar molecular weights within experimental error limits. This implies that most of the polymer chains were simply disentangled during the mixing process and not broken. Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) were done on the virgin polymer, the additives and the fabricated powders to determine the loading levels and to ascertain if there were any changes to the physical properties of the polymer. Scanning electron micrographs showed that some of the powder particles had additive particles stuck on the surface, but when these additives were washed off the surface of the powders with a suitable solvent that did not dissolve the polymer, DSC analysis showed the presence of additive incorporated into the polymer matrix.

Optimisation of the control of an autogenous grinding circuit requires a better understanding of system dynamics than exists at present. To this end extensive operating data were acquired on an industrial semi-autogenous milling circuit and a model was developed to explain the circuit responses to changes in input variables. This model represents the trends in the data fairly accurately and showed that: • When an excess o f slurry was present in Me load (i.e. more than the volume of the voids) a pool of slurry forms st the toe of the load. • The complexity of the power dependence on the variables describing the mill load defied dynamic modelling with toe limited knowledge avail- • The key parameters determining grinding efficiency vary constantly as the grinding environment is disturbed indicating a need for adaptive con- • The flow through the mili is adequately modelled by a single well mixed Itwasalso clear that maximisation of the power with respect to themass alone was insufficient, and that control of the feed dilution water rate is essential. Mill discharge slurry theology was studied eo gain an insight into conditions in the load. An energy balance using temperature measurements around th t mill discharge sump provided a very reliable estimate of the mill discharge density. This estimate was not successfully used for control although this potential should be exploited. Attempts to commission an on-line measurement of discharge slurry viscosity failed. Several theories and ideas were tested in a production environment subject to a multiplicity of disturbances and conclusive qualitative results were obtained. An improved understanding of milling circuit dynamics and a rationalisation of where controi can be improved has resulted from this work.

The work described in this thesis aims to conduct a systematic study of the two stage turbocharging system to improve the Diesel engine transient performance as well as NOX and CO2 emissions with a focus on the improved turbocharger matching and the control of the charging system, through the use of high fidelity engine models backed by experimental results. To perform the analytical study, commercial 1D simulation software has been used in the process of system characterisation and control strategy design. To validate the analytical results, a two stage turbocharging system was installed on a production diesel engine and tested on a transient engine test bench. The test results were then used to further calibrate the 1D engine/turbocharger model. Several other technologies were also investigated in simulation to explore their potential to further improve the system. Unlike most studies in the literature, this project focused on the system benefit of the engine and turbochargers, instead of conducting optimisation solely at the component level. The engine global parameters, such as the engine fuel consumption, emission levels and the transient response were the main parameters to be considered and were also best suited to the strengths of the 1D simulation method. The interactive use of both the analytical and experimental methods was also a strong point of this study. A novel control strategy for the system was proposed and demonstrated in the simulation. Experiments confirmed the validity of this control strategy and provided data for further model calibration. The comparison of the test results of the baseline engine to those obtained with the two stage turbocharged engine system verified the benefits of the novel turbocharging arrangement and control scheme. Transient response (T1090) was improved, with a 50% faster torque rise at 1000 rpm; the fuel consumption over the NEDC was 4% lower and NOx emissions over the NEDC were 28% lower. In the meantime, the study also revealed shortcomings of the system, such as the lack of EGR control at low speed, low load condition and a mid-speed fuel consumption deterioration of 13% on average at 3000 rpm due to excessive back pressure. With a novel 1D model corroborated using test results, exploratory simulation was done to rectify the aforementioned shortcomings and to further improve the system. Simulation results showed that by implementing VGT and ball bearing technology in the high pressure stage of the two stage system, the EGR controllability at low speed was regained and the excessive back pressure at high speed was improved. Consequently, the fuel consumption was only increased by 1.3% compared to the baseline NEDC operation and the transient response was on par with the original two stage system, with only 0.05s slower in torque rise at 1000 rpm, and still 48% faster than the baseline VGT system. Furthermore, the NOx emission can be expected to be greatly improved in the upcoming more intensive drive cycles compared to the NEDC cycle, with simulation showing NEDC NOX emissions dropped by 1%, comparing to a substantial reduction of 11% in WLTC.

O tênis de mesa é um dos esportes de raquete mais rápidos do mundo, exigindo muito pouco tempo para planejar e executar seus movimentos. Neste sentido, detectar a quantidade de rotação da bola, velocidade e direção torna-se fundamental para produzir respostas motoras eficientes. Entretanto, existem algumas questões que ainda não foram exploradas como o quanto a disponibilidade das informações auditiva e visual interfere na acurácia da percepção da rotação da bola e no tempo necessário para perceber estas rotações. O propósito do presente estudo foi analisar a influência da informação auditiva e visual na percepção da rotação da bola e no desempenho no tênis de mesa. Os atletas profissionais foram submetidos a dois estudos: o primeiro destinado a verificar a contribuição da informação auditiva e visual na percepção da rotação da bola e no tempo necessário para essa percepção. O segundo, proposto para avaliar a influência da informação auditiva no desempenho da tarefa de contra-ataque no tênis de mesa. Participaram do estudo 22 mesatenistas de alto rendimento de ambos os sexos (21 homens e 1 mulher) com média de idade de 22,55 ± 6,15. O teste de percepção de rotação (estudo 1) analisou o número de acertos e o tempo de reação por meio de uma rotina desenvolvida no software Matlab (Apêndice D). Os atletas visualizavam a tela de um computador e respondiam em um teclado o mais rápido possível. Os atletas analisaram um movimento de forehand nas intensidades de rotação: muita rotação (bola girando a aproximadamente 140 r/s); média (bola girando a aproximadamente 105 r/s); pouca rotação (bola girando a aproximadamente 84 r/s); batida chapada (bola girando a aproximadamente 70 r/s), nas seguintes condições: a) informação auditiva; b) informação visual; c) informação auditiva e visual. Os atletas analisaram 20 bolas para cada condição sendo cinco de cada tipo de efeito. Para o teste de desempenho (estudo 2) o atleta teve que responder adequadamente com o movimento de contra-ataque de forehand em um alvo previamente marcado na mesa. Foram golpeadas 80 bolas nas mesmas intensidades de rotação mencionadas acima. Os atletas foram avaliados em duas condições: com informação auditiva e sem informação auditiva. Os resultados do estudo 1 revelaram que mesatenistas foram capazes de perceber a magnitude de rotação da bola nas três condições. O percentual de acertos foi de 77,5%, 91,14% e 96,36% para as condições de informação auditiva, visual e combinadas, respectivamente. Quanto ao tempo de reação, os resultados revelaram que na condição somente informação auditiva (2,32 ± 0,41 s) os atletas demoraram mais tempo para responder do que em relação a condição somente informação visual (2,07 ± 0,36 s), já na condição informação auditiva e visual (1,85 ± 0,35 s) os atletas se mostraram mais rápidos ainda concordando com as informações número de acertos obtidas neste estudo. Para o estudo 2 os resultados revelaram que quando os atletas contra-atacaram na condição informação auditiva, o número de acertos foi de 37,69 ± 5,43 enquanto, quando a audição dos atletas foi privada a média de acertos foi 33,15 ± 6,84. Os resultados apontaram que mesatenistas foram capazes de utilizar as informações auditiva e visual para perceber a magnitude da rotação da bola no golpe forehand, porém, no estudo 1 quando as informações foram combinadas o número de acertos aumentou 5,22% e o tempo de reação diminuiu 0,22 s. No estudo 2 Quando a informação auditiva foi privada houve uma diminuição na média do número de acertos de 4,54. / Table tennis is one of the fastest racket sports in the world, requiring very little time to plan and execute your moves. In this sense, detecting a quantity of ball spin, velocity and direction becomes fundamental to produce efficient motor responses. However, there are some questions that have not yet been explored for example how much the availability of auditory and visual information interferes with the accuracy of the perception of the rotation of the ball and the time needed to perceive these rotations. The purpose of the present study is to analyze the influence of auditory and visual information on the perception of ball rotation and performance in table tennis. The volunteers were submitted to two studies: the first one to verify the contribution of the auditory and visual information in the perception of the rotation of the ball and in the time necessary for this perception. The second, proposed to evaluate the influence of auditory information on the performance of the counter-attack task in table tennis. Twenty-two high-level table tennis players men and women (21 men and 1 woman) with a mean age of 22.55 ± 6.15 participated in the study. The rotation perception test (study 1) analyzed the number of hits and the reaction time through a routine developed in Matlab software. The athletes visualized the screen of a computer and answered in a keyboard as soon as possible. The athletes analyzed a forehand movement in the rotation intensities: fast spin (spinning ball foward at 140 r/s); medium spin (105 r/s); slow spin (84 r/s); flat hit (70 r/s), under the following conditions: a) auditory information; b) visual information; c) auditory and visual information. The athletes analyzed 20 balls for each condition, five of each type of rotation. For the performance test (study 2) the athlete had to respond adequately with the forehand counterattack movement on a previously marked target at the table. 80 balls were struck at the same intensities of rotation mentioned above. The athletes were evaluated in two conditions: with auditory information and without auditory information. The results of the study 1 revealed that table tennis players were able to perceive the magnitude of rotation of the ball in the three conditions. The percentage of correct answers was 77.5%, 91.14% and 96.36% for auditory, visual and combined information conditions, respectively. Regarding the reaction time, the results revealed that in the condition only auditory information (2.32 ± 0.41 s) the athletes took more time to respond, since in the condition only visual information (2.07 ± 0.36 s) delayed a little less and in the condition auditory and visual information (1.85 ± 0.35 s) the athletes showed themselves to be faster still agreeing with the information number of hits obtained in this study. For the study 2 the results revealed that when the athletes counterattacked in the auditory information condition, the number of hits was 37.69 ± 5.43, whereas when the hearing of the athletes was private the average hit was 33.15 ± 6.84. The results indicated that table tennis players were able to use auditory and visual information to realize the magnitude of the ball rotation in the forehand blow, however, in study 1 when the informations were combined the number of right answered increased 5.22% and the reaction time decreased by 0.22 s. In study 2 When the auditory information was depriving, there was a decrease in the average number of hits 4.54.

A two-mass model with a spring and a damper in the vertical direction, accounting for vertical translational motion and a torsional spring and a damper connecting the rotational motion of two masses is used to simulate the dynamics of a tennis ball as it comes into contact with a flat surface. The model is supposed to behave as a rigid body in the horizontal direction. The model is used to predict contact of the ball with the ground and applies from start of contact to end of contact. The springs and dampers for both the vertical and the rotational direction are linear. Differential equations of motion for the two-mass system are formulated in a plane. Two scenarios of contact are considered: Slip and no-slip. In the slip case, Coulomb??s law relates the tangential contact force acting on the outer mass with the normal contact force, whereas in the no-slip case, a kinematic constraint relates the horizontal coordinate of the center of mass of the system with the rotational coordinate of the outer mass. Incorporating these constraints in the differential equations of motion and applying initial conditions, the equations are solved for kinematics and kinetics of these two different scenarios by application of the methods for the solutions of second-order linear differential equations. Experimental data for incidence and rebound kinematics of the tennis ball with incidence zero spin, topspin and backspin is available. The incidence angles in the data range from 17 degrees up to 70 degrees. Simulations using the developed equations are performed and for some specific ratios of inner and outer mass and mass moments of inertia, along with the spring-damper coefficients, theoretical predictions for the kinematics of rebound agree well with the experimental data. In many cases of incidence, the simulations predict transition from sliding to rolling during the contact, which is in accordance with the results obtained from available experimental measurements conducted on tennis balls. Thus the two-mass model provides a satisfactory approximation of the tennis ball dynamics during contact.

This thesis presents a skillful robotic wrist system using a visual servo control technique to demonstrate dexterity of the mechanical wrist from the viewpoint of the table tennis. A ball and plate system is chosen as the first stage of this long-term project. A two degrees-of-freedom robotic wrist with an acrylic plate attached as the end effector is developed. A visual feedback control system is implemented with a web cam and a personal computer to acquire the ball's position. In order to implement decision making for changing orientation of the plate, a Linear Quadratic Regulator (LQR) is designed. As a result, the ball can be balanced at specific positions. Experimental results exhibit preliminary and promising achievement. Based on this progress, further improvement and deeper exploration can be carried on in the future.

Since oil-in-water emulsions combine good cooling and lubricating capabilities, they have been commonly used in cold rolling nowadays. In order to understand the tribology characteristics of the emulsion during the cold rolling process, the effects of load, sliding speed, material of specimen, surface roughness and type of emulsion on the tribology characteristics of cold rolling are investigated by using the multi-purpose friction and wear tester.The P (load) ¡VV (sliding speed) curve was investigated under the conditions of load (below 2.4GPa), sliding speed (below 2.2m/s) at lower specimen roughness. Results show that QK-N36 emulsion can differentiate between boundary lubrication regime and initial seizure according to their friction coefficient, but RL-61 emulsion cannot differentiate them. Therefore, the load carrying capacity of RL-61 emulsion is better than that of QK-N36 emulsion, and its friction coefficient is also lower than that of QK-N36 emulsion. However, this tendency of experimental results is different from the cold-rolling practice.Under the lower load and higher surface roughness conditions with different hardness of specimen, the friction coefficient of RL-61 emulsion is higher than that of QK-N36 emulsion. This tendency of experimental results is the same as the rolling practice. Under the lower load condition with SDK-11 specimen, the friction coefficient of RL-61 emulsion varies gradually in the range of 0.07 ~ 0.09 located in the boundary lubrication regime, but the friction coefficient of QK-N36 emulsion reduces to 0.02~0.04 located in the mixed lubrication regime.