The objective of this research is to assess the performance of two popularReynolds-averaged Navier-Stokes (RANS) models, standard k-E and k-w, andto suggest modifications to improve model predictions for high-speed flows. Numerical simulations of turbulent ow past a at plate are performed at M1 = 2:25; 7:2.The results from these two Mach number cases are compared with Direct NumericalSimulation (DNS) results from Pirozzoli et al. (2004) and experimental results fromHorstman & Owen (1975). The effect of the Boussinesq coefficient (Cu) and turbulenttransport coefficients (sigmak; sigmaE; sigma; sigma*) on the boundary layer ow is examined. Further,the performance of a new model with realizability-based correction to Cu and corresponding modifications to sigma; sigma* is examined. The modification to Cu is based oncontrolling the ratio of production to dissipation of kinetic energy (P/E=1). The firstchoice of P/E = 1 ensures that there is no accumulation of kinetic energy in stagnation or free-stream regions of the ow. The second choice of P/E= 1:6 holds underthe assumption of a homogeneous shear ow. It is observed that the new model'sperformance is similar to that of the existing RANS models, which is expected for asimple ow over a at plate. Finally, the role of turbulent Prandtl number (Prt) intemperature and density predictions is established. The results indicate that the k-wmodel's performance is better compared to that of the standard k-E model for highMach number flows. A modification to Cu must be accompanied with correspondingchanges to sigmak; sigmaE; sigma; sigma* for an accurate log-layer prediction. The results also indicate that a Prt variation is required across the boundary layer for improved temperatureand density predictions in high-speed flows.

The importance of the use of renewable energy sources is obviously. But what the problem confused us, is that renewable energy unlike the fossil fuel have such high energy density which means the renewable generally was dispersed form. In other words, in order to obtain amount of the energy we need, require to exploitation a wider cover area. Therefore, scientists and companies are struggling to find high densely renewable energy as possible, which is high altitude wind energy, have very promising but not developed so much by humans. High altitude wind power is indicating the altitude between 3000 meters and 10000 meters. So far, high altitude wind power is a new renewable energy that basically not development or utilization yet, but which is an abundant reserves. High altitude wind power is a widely distributed renewable clean energy. The characterized of high-altitude wind energy is fast speed, wide distribution, high stability and perennial. Utilize high-altitude wind power can get high stability with low cost of wind power generation, which is one of the notable features for high-altitude wind power, but also is one of the most significant advantages for high-altitude wind energy compared to conventional wind energy. High altitude wind power generation equipment is more compact and flexible, far superior then the traditional fan, which equip with thick blades and the tower must be fixed in the depths of the ocean or in the ground.To development renewable power in a large scale, to face the global climate change, achieve the sustainable development become the inevitable for human development. How to solve the energy shortage problem has become an important question, harness high altitude wind power was becomes the focus of multinational technology.

Purpose: To investigate the differential effects of solutions providing varying concentrations of carbohydrate and/or protein ingested between 200-meter sprints on sprint time. Subjects: Recruitment was from the Georgia State University track and field team. Methods: The study protocol was approved by the Georgia State University IRB. Ten subjects, 18 to 21 years of age, consented to be included in the study. Nine subjects (7 females; 2 males) completed trial 1, six subjects (5 females; 1 male) completed trial 2, and three subjects (2 females; 1 male) completed the final trial. Each trial consisted of a 200-meter sprint followed by the immediate ingestion of a post-exercise recovery beverage within the first fifteen minutes of a one-hour recovery period. Following the one-hour of recovery, subjects sprinted a second 200-meter sprint. Beverage solutions were formulated to contain 1.2 g of protein (PRO), 1.2 g carbohydrate (CHO), or 1.2 g carbohydrate with protein (CHO/PRO) per kg of subject body weight. Using a single blind, non-randomized design, subjects received the same recovery beverage in each trial. Each trial consisted of either PRO (trial 1), CHO (trial 2), or CHO/PRO (trial 3), with one week separating trials. Sprint times were recorded in seconds and ten hundredths of a second using a manual, digital stopwatch. Results: During PRO, two subjects sprinted faster (x= -.25 sec), three subjects saw no change in sprint time, and four subjects sprinted slower (x= +.98 sec). During CHO, two female subjects sprinted faster between sprints (x= -.85 sec); and all other subjects (n=4) sprinted slower (x= +.73 sec). During CHO/PRO, no subjects sprinted faster from sprint 1 to sprint 2 (x= +.33 sec) Conclusions: Post-exercise nutritional supplementation effects varied among subjects, with some subjects performing better following PRO, while others experiencing improvements with CHO. In general, subjects performed better following consumption of the CHO beverage. Of those who ran faster between sprints, the CHO beverage resulted in an average improvement of -.85 sec, while the PRO beverage resulted in an average improvement of -.25 sec. On average, CHO resulted in faster 2nd sprints (x= +.20 sec) than the PRO beverage (x= +.47 sec) or the CHO/PRO beverage (x= +.33 sec). Continued research in this population is necessary for elucidation of study results. This investigation may serve as the foundation for future, related studies.

This project has been assigned by SwePart Transmissions AB. It is about calculation and dimensioning, of the elements in a cycloid stage of a speed reducer. Their idea is to use the results from this project and go into production of such reducer to cover another segment of the market. The company is interested in supplying transmissions for robust systems and for various industrial purposes, where large ratios of speed reduction are needed. The company has given the necessary input data for the model. They have also provided a real cyclo-drive reducer for further analyses. To obtain the dimensions and forming the geometry of the gears, some parts of Professor Ognyan Alipiev’s Phd work have been used. Professor Alipiev is head of “Theory of Mechanisms and Machines” department in University of Ruse “Angel Kunchev”, Bulgaria. For the determination of forces on the elements, models and drawings has been used Solidworks (SW) CAD software and SW simulation environment. The resultant calculation process can be used for designing the geometry and determination of the properties regarding the cycloid reducer. / Design of a Planetary-Cyclo-Drive Speed Reducer

The objective of this work was to design high-speed circuits using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) and complementary SiGe (C-SiGe) HBTs, as well as silicon (Si) complementary metal oxide semiconductor (CMOS) devices, for next-generation ultra-wideband (UWB) transceivers. The advantages of using UWB systems over conventional narrowband transceivers include their lower power requirements, higher data rate, more efficient spectrum usage, precise positioning capability, lower complexity, and lower cost. The two major components in a UWB transceiver IC are the radio frequency (RF) circuit and the analog-to-digital converter (ADC). In this work, circuit-level solutions to improve the speed and performance of critical building blocks in both the RF front-end and the ADC are presented. Device-related issues affecting SiGe HBTs for potential applications in UWB systems intended for use in extreme environments will also be investigated. This research envisions to realize various circuit blocks in a UWB transceiver including, a 3-10 GHz UWB low noise amplifiers (LNAs) in both the second (120 GHz) and third (200 GHz) SiGe technologies, an 8-bit 12 GSample/sec SiGe BiCMOS track-and-hold amplifier (THA), and a fifth order elliptic gm-c low-pass filter in C-SiGe HBT technology. This research will also focus on characterizing SiGe HBTs for UWB electronics for operation in extreme environments by investigating the proton radiation effects in the third generation SiGe HBTs.

ABSTRACT The design and fabrication of a rotating electromagnetic generator of low-speed and small bicycle were presented in this study. In accordance with the standard of generator the finite element analysis was used to design the prototype generator. In the simulation, the different parameters of the magnet, coil and iron yoke were set into the Taguchi method to find the best configuration. The parameters included the magnet poles, coil size, wire thickness, winding way, with or without iron yoke, and the distance between the magnet and yoke. When a permanent magnet is moved relative to a coil, an electromotive force is created. According to the theory of electromagnetic induction, the electricity was generated by the electromagnetic power generator. In this study, power produced by the relative motion between coil and magnet. This project innovatively uses Low-Temperature Co-fired Ceramic(LTCC) technology to fabricate micro-coil, and the required magnetic characteristics of permanent magnet are produced by sintered Nd-Fe-B. The technology and simulation were combined to achieve the requirements of lightweight, compact, high energy density. A prototype of the micro-generator is 50x50x4.5 mm3 in volume size. The 28 poles hard magnet Nd/Fe/B with an outer diameter of 50 mm and a thickness of 2 mm was molded and sintered, and provides the magnetic field of 3.5 Tesla. The coils with a width of 200£gm, a pitch 100£gm and the thickness of 40£gm were fabricated by silver. The coils had 30 layers and 22 poles. A steel yoke can improve the efficiency of power generation. The results of induced electromotive force were 0.61, 0.97 and 1.45V at the rotational speeds of 37rpm, 74rpm and 111rpm respectively in the simulation.

Driving a horizontal roadway curve requires a change in vehicle alignment and a potential reduction in speed. Curves may present a challenging situation during adverse conditions or to inattentive drivers. Chevron signs provide advanced warning and positive guidance throughout the curve. Some agencies place supplemental retroreflective material on sign posts to enhance the signs? conspicuity and visibility. The objective of this study was to determine any incremental benefits in vehicle speed and lateral lane position when retroreflective material was applied to Chevron sign posts (ChevFull). This study analyzed three separate evaluation scenarios in a before, after, and after-after experimental design. There was an existing Baseline evaluation with no vertical delineation, a standard Chevron evaluation, and an experimental ChevFull treatment evaluation. Data collection measured vehicle speed and lateral position data at the point of curvature and mid-point on two separate curves. Findings showed that both Chevrons and the ChevFull treatment moved vehicles away from oncoming traffic by about 15 inches. Overall, there was little difference between the lateral position findings of the two Chevron treatment scenarios. Chevrons achieved a 1.28 MPH reduction in mean vehicle speed from the Baseline evaluation and the ChevFull treatment obtained a 2.20 MPH reduction. The findings determined that the benefits of the ChevFull treatment were not substantial. The author recommends that the MUTCD should continue to present the ChevFull treatment as an optional delineation tool. Based on this research, the author does not recommend any changes to the MUTCD.

Power systems on modern commercial transportation systems are moving to more electric based equipment, thus improving the reliability of the overall system. Electrical equipment on such systems will include some loads that require very high power for short periods of time, on the order of a few seconds, especially during acceleration and deceleration. The current approach to solving this problem is sizing the electrical grid for peak power, rather than the average. A method to efficiently store and discharge the pulsed power is necessary to eliminate the cost and weight of oversized generation equipment to support the pulsed power needs of these applications. Highspeed Flywheel Energy Storage Systems (FESS) are effectively capable of filling the niche of short duration, high cycle life applications where batteries and ultra capacitors are not usable. In order to have an efficient high-speed FESS, performing three important steps towards the design of the overall system are extremely vital. These steps are modeling, analysis and control of the FESS that are thoroughly investigated in this dissertation. This dissertation establishes a comprehensive analysis of a high-speed FESS in steady state and transient operations. To do so, an accurate model for the complete FESS is derived. State space averaging approach is used to develop DC and small-signal AC models of the system. These models effectively simplify analysis of the FESS and give a strong physical intuition to the complete system. In addition, they result in saving time and money by avoiding time consuming simulations performed by expensive packages, such as Simulink, PSIM, etc. In the next step, two important factors affecting operation of the Permanent Magnet Synchronous Machine (PMSM) implemented in the high-speed FESS are investigated in detail and outline a proper control strategy to achieve the required performance by the system. Next, a novel design algorithm developed by S.P. Bhattacharyya is used to design the control system. The algorithm has been implemented to a motor drive system, for the first time, in this work. Development of the complete set of the current- and speed-loop proportional-integral controller gains stabilizing the system is the result of this implementation. In the last part of the dissertation, based on the information and data achieved from the analysis and simulations, two parts of the FESS, inverter/rectifier and external inductor, are designed and the former one is manufactured. To verify the validity and feasibility of the proposed controller, several simulations and experimental results on a laboratory prototype are presented.

The objective of this research is to assess the performance of two popularReynolds-averaged Navier-Stokes (RANS) models, standard k-E and k-w, andto suggest modifications to improve model predictions for high-speed flows. Numerical simulations of turbulent ow past a at plate are performed at M1 = 2:25; 7:2.The results from these two Mach number cases are compared with Direct NumericalSimulation (DNS) results from Pirozzoli et al. (2004) and experimental results fromHorstman & Owen (1975). The effect of the Boussinesq coefficient (Cu) and turbulenttransport coefficients (sigmak; sigmaE; sigma; sigma*) on the boundary layer ow is examined. Further,the performance of a new model with realizability-based correction to Cu and corresponding modifications to sigma; sigma* is examined. The modification to Cu is based oncontrolling the ratio of production to dissipation of kinetic energy (P/E=1). The firstchoice of P/E = 1 ensures that there is no accumulation of kinetic energy in stagnation or free-stream regions of the ow. The second choice of P/E= 1:6 holds underthe assumption of a homogeneous shear ow. It is observed that the new model'sperformance is similar to that of the existing RANS models, which is expected for asimple ow over a at plate. Finally, the role of turbulent Prandtl number (Prt) intemperature and density predictions is established. The results indicate that the k-wmodel's performance is better compared to that of the standard k-E model for highMach number flows. A modification to Cu must be accompanied with correspondingchanges to sigmak; sigmaE; sigma; sigma* for an accurate log-layer prediction. The results also indicate that a Prt variation is required across the boundary layer for improved temperatureand density predictions in high-speed flows.

This thesis documents the linear mixed model developed for vehicle speed along two-lane two-way rural horizontal curves in the outside lane. Speed data at each curve was collected at four points along the curve including the midpoint of the curve for a minimum of 48 hours during weekdays. Vehicle speed was analyzed separately for day and night conditions. The horizontal curves were categorized into different groups using different methods using side friction demand, radius and pavement edgeline marking retroreflectivity. In the speed prediction model, radius, superelevation at the midpoint of the curve, deflection angle, posted speed limit and pavement edgeline marking retroreflectivity were used to predict the vehicle speed at the midpoint of the horizontal curve. The regression analysis indicates that all of these variables are statistically significant in predicting the vehicle speed at the midpoint of horizontal curves with a 95 percent confidence interval. The linear model determined that the vehicle speed has a positive relation with the radius of the curve, superelevation and posted speed limit but has a negative relation with the deflection angle and pavement edgeline marking retroreflectivity. Curves were categorized based on side friction demand or radius and retroreflectivity of pavement edgeline marking. ANOVA was used to compare the day and night time speed. The comparisons reveal that vehicle speed at the horizontal curves decreases as the side friction demand value of the curves increases. Another finding of this research was that even though the posted speed limit is incorporated into the calculation of side friction demand, it may be necessary to analyze the impact of posted speed limit on vehicle speed for both daytime and nighttime. Previous literature determined that drivers may drive at an unsafe speed during nighttime at high levels of retroreflectivity. The results of this study could not confirm this statement as data from this study suggests that for curves with pavement edgeline marking retroreflectivity greater than 90 mcd/m2/lx, the effects of retroreflectivity on speed was determined to be minimal. This is based on the finding that the daytime and nighttime speeda were basically the same as the daytime and nighttime speed difference was both statistically and practically insignificant.