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M.Ed. / Computers are an integral part of life, and have become integral to everyday functions of work, travel, health, entertainment and study. It is crucial that this technology be utilised to maximum effect. In schools, learners are increasingly required to enhance their computer skills, and at tertiary level students explore ways they can be used to develop and enhance capacity, functions and responsibilities. This study examines ways in which computer technology can be used to teach, so as to benefit all role-players in the learning process, including lecturers, students, the learning fraternity and industry, contributing to a more competent and capacitated workforce. In particular, it looks at an electronic assessment tool implemented by the University of Johannesburg (UJ), intended to enhance and upgrade learning in courses where computers are used. However, with the initial use of system, certain shortcomings were identified which affected its performance. As computer-related testing was considered important in contributing to assessment, it was critical to identify any problems that were inhibiting its optimal performance. To this end, the researcher studied the subdepartment End-User Computing (EUC), located within the department of Business Information Technology (BIT) at UJ. A qualitative phase consisted of two identified focus groups made up of specific individuals from BIT, comprising lecturers engaged in the daily use and activation of the electronic assessment system and supported by information system technical support personnel. A second phase, quantitative in nature, used responses to structured questionnaires delivered to students who had used the assessment tool. The University’s Statcon unit analysed results, and identified problems. Lecturers pointed to the language used in questions and system challenges to teaching and learning, while students highlighted a need for preparing them for the process, particularly calling for a tutorial with class presentation prior to assessment.

Submitted in fulfillment of the requirements for the degree of Master in Technology, Durban University of Technology, Durban, South Africa, 2015. / The primary objective of this research was to investigate the failures occurring in the family of surge arresters used within EThekwini Electricity, making use of different diagnostic methods, such as leakage current testing (LC), infrared scanning (IR), and partial discharge (PD) measurements. The different diagnostic tests were used to assess the degradation process of the polymer housed surge arresters and their failure. The measurements were used for diagnosis of 120 kV/65 kA surge arresters of different brands. Tests were performed on surge arresters that were still in the system and these test results were compared with results from tests performed on failed units. Results obtained from the different tests were compared to the test results for different families or designs. An imperfect arrester will exhibit excessive heating when an electrical surge is discharged. The aforementioned tenets are the primary factors influencing degradation and causing failure of Metal Oxide Surge Arrester (MOSA) in a system. These factors can decrease creepage and flashover distance on insulation, which could result in a substantial increase in resistive leakage current, (which is a few microamperes in ideal condition), overheating, and PD formation on the zinc oxide varistor element. Therefore, it is extremely important to assess the status of the surge arresters whilst they are in service, firstly so that they can be removed from the system before they fail and, and secondly, to verify their condition, and their ability to effectively protect the substation apparatus. Using infrared inspection, valuable information of condition of surge arresters was obtained, heat inside the surge arresters was detected and this shows that IR analysis can therefore be considered as an additional method to assess the condition of polymer housed surge arresters. It was observed that partial discharge activity is an indication of degradation in arrester varistor. LC test, IR, and PD measurement were valuable in obtaining sufficient information for failure of surge arresters. In additional, during the visual internal inspection of arresters, evidence of punctures, treeing, tracking, and moisture masks were noted on ZnO blocks and seals. These results indicate that the moisture ingress through the sealing collar can cause unnecessary outages. / M

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 65. / by Mark Howard Sloan. / B.S.

In modern life, human have become dependent on portable electronics, such as cell phones, MP3 and handheld computers, most of which are powered by batteries. Although the performance of batteries is being continuously improved, the limited energy storage and service life constrain the lasting use of these mobile electronics. Therefore it is desirable to find alternative or supplementary methods to solve this problem from its root cause. It is known that human body contains rich chemical energy, part of which is converted to mechanical energy up to 200W when in motion, so it is ideal to harvest a small fraction of the human kinetic energy to power mobile electronic devices. / In this thesis, first, the previous work done by other researchers on energy harvesting from human motion, especially from unintentional human motion, such as arm swing and leg moving, is reviewed. Then the fundamental principles to mechanically harvest motion energy are discussed, including the mechanical oscillating mechanisms and electromagnetic transduction. Derived from the general harvesting model, four different devices are designed and analyzed. / Shoe is important for human, one of which functions is to serve as shock-absorber to protect foot from the large impact force. As the foot strikes the ground, the shoe is subject to not only large force but also large displacement in the heel. The third new device is designed to insert in the shoe heel to harvest the kinetic energy from foot strike, and at the same time to function as a shock absorber for foot. Considering the stability and efficiency, a spring-slider-crank mechanism is used in this harvester to covert the up-down foot strike motion into unidirectional rotation to drive an AC generator. The spring and slider compose an oscillating system to absorb the foot strike motion, and crank and slider make up the conversion mechanism to transfer the bi-directional translation into unidirectional rotation. A set of gear is used to speed up the rotation. The kinematical performance of the harvester is also analyzed. / The first one is the automatic winding mechanism of mechanical movement. It consists of an oscillating weight, a ratchet mechanism, a gear set and a mainspring. The mechanism can be modeled as a double pendulum when worn on a user's wrist. Its kinematical performance is analyzed with experimental validation. / This thesis discusses the feasibility of mechanical power generators driven by human motion, with the focus on their architecture design and performance analysis. The main objective is to develop effective power generators for harvesting the energy from human motion, and use it to power portable electronic devices. / To directly convert the human arm motion to electricity, the second novel energy harvester is designed, analyzed and simulated. It mainly consists of an eccentric rotor made of permanent magnet, and a set of coils as a stator. The eccentric rotor, as a simple pendulum, acts as the kinetic energy harvester which absorbs the motion from human body in motion. With the permanent magnets on the rotor, the moving rotor produces a changing magnetic field, from which the stator induces electricity. In this design, a torsion spring is also added onto the rotor so that the harvester works even when the motion is on horizontal plane. / When foot strikes the ground, a large acceleration is produced. The fourth new energy harvester uses dual-oscillating mode. It contains two oscillating mechanisms: one is spring-mass oscillator to absorb the vibration from footstep motion, and the other is cantilever beam using the tip mass to amplify the vibration. Analysis shows that the dual-oscillating mechanism can be more effectively harvest the foot step motion. The energy conversion sub-mechanism is based on the electromagnetic induction, where the coils fixed at the tip end of the cantilever beam serves as the slider, and the fixed permanent magnets and yoke produce the changing magnetic field. Mathematical analysis and simulation are included. / Xie, Longhan. / Adviser: Ruxu Du. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 124-128). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Bibliography : leaves 127-133. / M.S.

The topic of this thesis is the design of an automatic preanodizer to be used to preadjust precision tantalum resistors by anodizing their surfaces. The purpose of the preanodizer is to generate a controllable voltage ramp to be applied to a set of tantalum resistors which are immersed in a suitable electrolyte. The slope and maximum value of the voltage ramp are set to produce the current required for proper anodization of the resistors. The rate of anodization determines the rate of change of the resistor value. This thesis covers the design of an electronic device to meet a set of requirements specified by the Western Electric Company. The primary tasks the device has to perform are the generation of a linear voltage ramp of adjustable slope and maximum voltage and the supply of a given maximum current. Metering circuits are provided to measure, store and display the current and the maximum value reached by the ramp voltage.

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 7, 2007). Includes bibliographical references.

Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Materials Science and Engineering Program, 2006. / Includes bibliographical references.

With the advancement in wireless communication, there has been a lot of overlap in the frequency spectrum used by different applications in the lower frequency band. Also there is an ever-increasing demand for high-speed wireless data transfer. Due to the aforementioned reasons, a lot of work is being done recently in the unlicensed 60GHz bandwidth due to the high data rates it can support. But it is tough to achieve long-range point-to-point transmission at this frequency due to the limited output power and high path losses. A phased array system is a viable solution at these mmWave frequencies to achieve highly directive long-range point-to-point communication. The objective of this research is the design and implementation of phase shifters, VCO and LNA for mmWave phased array system. In this work, active and passive quadrature generation schemes integrated with a vector modulator have been proposed that can be used to produce arbitrary phase shift with a deterministic resolution at the LO signal. Also, alternate IF and PLL based phase shifting schemes for a mmWave phased array system have been proposed. A complete design procedure from parasitic modeling of devices to verification of the design using EM simulations has been discussed in this work. The simulation results are compared with actual measurement results from the fabricated chip and the performance of the various circuits has been analyzed. Furthermore, the designs of VCO and low noise amplifier to be used in the mmWave phased array system are discussed here.