Submitted in fulfillment of the requirements for the Master of Engineering Degree, Department of Electronic Engineering, Durban University of Technology, Durban, South Africa, 2016. / The aim of this research project is to design a three phase four quadrant variable speed drive (VSD) for a permanent magnet brushless direct current motor (PMBLDC) that can be applied to an electric bicycle (e-bike). The design is confined to PMBLDC motors with a maximum power rating of 1.5kW. The speed controller operates in current mode at a maximum voltage and current rating of 50V and 30A, respectively. The VSD has the ability to smoothly control the current delivered to the DC motor and therefore controls its torque. The motor’s current is limited in all four quadrants of operation, and its speed is limited in the forward and reverse directions. The performance of the proposed DC motor VSD system is tested on an electric- bicycle. The PMBLDC motor has three hall sensors embedded into the stator to determine rotor position. A phase switcher module interprets the position signals and produces a switching pattern. This effectively transforms the BLDC motor into a direct current (DC) brushed motor. The unipolar switching scheme used ensures that current flows out of the battery only for motoring operation and into the battery during regenerative braking. The current and torque are directly proportional in a BLDC motor. Torque control is achieved in the BLDC motor using a single channel current controller. The phase switcher current is monitored and used to control the duty cycle of the synchronous converter switches. The proposed e-bike speed control system provides efficient control in all four quadrants of operation and it is a suitable alternative for a low cost transportation mode. / M

Cheung, Wai Ming Edwin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 107-112). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

Certain measures of aerobic power have been shown to have a high relationship with endurance performance. Critical power (CP) has also been shown to be well correlated to endurance performance, but few studies have evaluated its use in a competitive scenario. In this study, cardiorespiratory-metabolic measures were evaluated in 13 highly trained cyclists to determine their relationship to performance in a 17 km time trial. Critical power, determined from the nonlinear power-time model, was also evaluated to determine its relationship to performance in a 17 km time trial. Results indicate that the traditional indicators of V02max and ventilatory anaerobic threshold were well correlated to TT performance (r=-0.86, r=-0.79, respectively). The principal finding from this study was that performance in a bicycle time trial is related to CP at least as well as to cardiorespirator-ymetabolic measures. In fact, the results fromthis study suggest that the relationship between performance and CP is stronger (r=-0.89). Use of the critical power concept is attractive because testing requires only a cycle ergometer and a stopwatch to estimate a parameter of aerobic fitness.

For the past years, our laboratory has been interested in the development of a specific class of functionalised orthoester derivatives and their application as annelating reagents. Previous work had demonstrated that these reagents could be used in a two-step procedure to generate interesting spirocyclic ketones. At the onset of our thesis, we devoted our efforts to the study and application of this methodology. This resulted in an improved and more efficient procedure for the spirohexannelation of â-ketoketals. During these initial studies, an intriguing and novel transannular cyclisation was discovered. The reactivity of these spirocycles was also briefly examined, laying the ground for an application to the total synthesis of Agarospirol, Hinesol and á-Vetispirene, three natural products belonging to the Spirovetivane family. The applicability of a CAN-catalysed deprotection of ketals and silyl ethers, in the presence of an enol triflate moiety, was also investigated. The potential of our functionalised orthoesters as annelating agents was then further evaluated in the context of other silyl enolethers. The heteroaromatic derivatives of furan proved to be excellent coupling partners for our functionalised orthoesters, and enabled the efficient preparation of a wide array of butenolides. These butenolides could then be elaborated, by an efficient and highly stereoselective radical-mediated cyclisation, into bicyclic lactones. Alternatively, treatment with base triggered an efficient spirocyclisation, delivering spirocyclic butenolides in good to excellent yields. The corresponding pyrrole derivative was also examinated, and preliminary work hints at the possibility of readily preparing azaspirocycles as well as indolizidine frameworks. Finally, the evaluation of silylated acyloins allowed an entry into the chemistry of cyclobutanones, and a simple procedure for the synthesis of spirocyclic ethers was developed. During these investigations, an unexpected fragmentation was serendipitously discovered upon application of the Beckmann rearrangement. We were able to use this reaction in a new procedure for the synthesis of interestingly substituted tetrahydropyrans.

This study investigated the opinions of bicyclists/pedestrians regarding how safe from a bicycle traffic injury they felt while on campus. Most earlier studies had been concerned with the taxonomy of bicycle/pedestrian accidents. Because of the paucity of research on attitudes of bicyclists and pedestrians, this research was undertaken. The survey instrument was developed in accordance with recommendations from the Oregon State University Survey & Research Center. It consisted of 19 Likert type, degree of variation statements, and ten biographical questions. The sample consisted of 214 students registered for the winter term of 1986 at Oregon State University. Participants completed the Traffic Safety Attitude Survey and then were placed in the following categories: male, female, bicyclists, and pedestrians. The Survey instrument was designed to test four null hypotheses and to define other broadly held opinions regarding traffic safety on campus. Hypotheses One through Three tested interaction between bicyclists/pedestrians. The fourth hypothesis tested the difference between male bicyclists and male pedestrians and female bicyclists and female pedestrians. The Chi Square Test and a two-way analysis of variance were employed to test the hypotheses. Two significant findings emerged from hypothesis testing: 1) bicyclists and pedestrians differed on the opinion that as much as possible is being done to provide campus bicycle traffic safety, and 2) pedestrians endorsed stricter adherence to bicycle traffic regulations than bicyclists. There was no difference between bicyclists and pedestrians regarding feelings of safety from a bicycle traffic-related injury. Finally, gender had no effect on perceptions of campus bicycle traffic safety. Analysis of the results of this research provided the following conclusions: 1. Male bicyclists felt the least at risk of injury from a bicycle traffic-related injury on campus. 2. Female pedestrians felt the most risk of injury from a bicycle traffic accident on campus. 3. Female bicyclists, female pedestrians, and male pedestrians shared similar opinions regarding risk of exposure to a bicycle traffic accident on campus. 4. Approximately 30% of all subjects felt there is a problem with interaction between bicyclists and pedestrians on the OSU campus. 5. Approximately 46% of the pedestrians and 25% of the bicyclists felt risk of sustaining a bicycle traffic-related injury on campus. 6. Approximately 38% of the pedestrians and 25% of the bicyclists support some form of bicycle traffic restriction. 7. Pedestrians endorse stricter adherance to bicycle traffic regulations that bicyclists do. 8: Pedestrians felt less is being done to ensure bicycle traffic safety on campus than bicyclists did. / Graduation date: 1986

Graduation date: 1992

Since a young age, I have been interested in bicycling as a form of fun and fanciful recreation, but it wasn’t until the summer of 2011 that a serious shift occurred in my understanding of the bike as more than a mere machine. A spontaneous 700-mile journey redefined my relationship with travel, transcended my notions of transportation, and enabled me to better mediate myself within my environment. In writing about these experiences, I hope to offer some insight into how American culture currently frames transportation and how I hope the construction of a bike positive culture can instill social, environmental, and political change. Concurrently, I created a pin-up style bicycle calendar featuring enthusiasts from the Claremont Colleges to foster a sense of community around bicycling and inspire riders and non-riders alike to further explore their ‘bicyxuality’. Intermingling this nonfiction piece with a thoughtful reflection on the BIKEurious calendar project, this paper serves to explain my creative undertakings and, ultimately, call into question the hierarchy of transportation in America today.

No description available.

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 70-73). Also available on the World Wide Web.

x, 61 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Around the world, active transportation is looked at as one solution to problems presented by climate change, epidemic obesity, rising fuel prices, and crippling traffic congestion. In 2008, the University of Oregon launched the Bike Loan Program as an effort to address these issues. Because those interested in participating in the Bike Loan Program were randomly selected based on bicycle size availability, those who were not chosen acted as a perfect control group. This study evaluates the impacts of the Bike Loan Program on participants vis-a.-vis non-participants, and seeks to determine if those participating do ride bikes more often than non-participants. This study will also show what modes of transportation are being replaced by bike trips when a person participates in the Bike Loan Program. Finally, this study also shows if there are changes in attitudes or perceptions about transportation resulting from participation in the program. / Committee in Charge: Dr. Neil Bania; Dr. Marc Schlossberg; David Roth