Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2006 / The electrical supply utility, ESKOM, cannot cope with the growing demand in South Africa. This results in load shedding and power outages. This capacity can be augmented, by conducting energy audits, retrofitting government buildings, designing and installing cost-effective lighting systems, and using renewable energy sources in rural areas. Households in rural areas depend on candles and paraffin lamps to supply light at night. Solar panels as renewable energy sources are very expensive in conventional lighting systems. The problem is that a cost-effective, affordable lighting system has not yet been designed. The following four projects have been completed by the author: - Software development for a lighting design in general - Efficient high bright light emitting diode (HB-LED) lighting system - Energy audit and retrofit of the Nuwe Hoop School in Worcester - Optimization of hybrid solar-diesel system Firstly, the author wrote a program that is used in lighting designs. This illumination software is utilized for educational purposes. A manual step-by-step lighting design procedure was compiled. The JAVA object-oriented programming language was used to write the code of the design software. Real life design parameters are fed to the program, to confirm proper implementation. The software package will perform illuminance calculations to display relevant Isolux diagrams for educational purposes.

Call number: LD2668 .T4 1979 R62 / Master of Architecture

Call number: LD2668 .T4 1957 T82 / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Industrial Engineering.

One of the greatest technological breakthroughs of humanity was the ability to construct a device and eventually a system which would provide a more efficient, safe, clean, convenient and relatively inexpensive form of illumination than ever used previously electric light. The introduction of this new technology into Oregon communities in the early years of this century was a remarkable accomplishment. Along with memories of the light itself, important and intriguing recollections of "life lived yesterday" are often associated with these early days of electric lighting. Because these "yesterdays" are becoming more distant from the present, persons holding those memories are reaching ages where such information becomes difficult to recall, vague, distorted and often forgotten altogether. In this study, memories of how electric light affected people were recalled differently in some aspect by informants, whether it was used for the purpose of lighting streets and buildings or on personal properties within the home and on farms. Published information describing the effects of electric lighting on society is relatively scarce. Consequently, persons with important previous experiences are in many instances the only source of insight on how our predecessors lived before electric light was in use and especially how this technological breakthrough may or may not have affected their lives. Those published descriptions of pre-electric life that do exist are most commonly found in obscure publications, often originating in small or private electric company newsletters and annual reports. Very few of these reports were compiled in a systematic scheme later to be interpreted quantitatively and in light of previous research. My own interest in this subject was piqued when I realized that both oral histories and technical data on how electricity affected individuals of the Pacific Northwest region is profoundly poor in comparison to material available on other parts of the country. With this understanding, 32 individuals representing a span of 30 years, five states and 15 different communities throughout Oregon, were interviewed over the course of four months. The informants were asked questions pertaining to their lifestyle and memories before, during and after the introduction of electricity, and more specifically about the advent of electric light into their communities and homes. Because the study utilized a minuscule sample size in comparison to the state population, generalizations were not appropriate. Nevertheless, the oral histories provided a greater insight into how the introduction of electric light and electric power affected the life of an Oregonian. / Graduation date: 1994

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 26, 2008) Includes bibliographical references (p. 83-84).

The object of this investigation is to make a comprehensive study and obtain reliable information on the possibilities and limitations of an isolated electric light plant; operating cost will be determined with practical equipment to be used in connection with same, under actual farm conditions. The study was made on "Sandy Mound Farm" owned and operated by Mr. W. E. Hubbard. The farm is located two and one-half miles from Blacksburg, Virginia, near Shadow Lake. It consists of about 180 acres of crop land and 60 acres or woods. Mr. Hubbard operates a 20-cow dairy and sells cream to the southern Dairies at Christiansburg, Virginia. A complete farm management study was made of this farm as a Minor Problem. The subject of this study is the new Four Cylinder Delco Light plant, Model No. 178, generating unit,end 160 amphers an hour battery. / M.S.

Thesis (Magister Technologiae - Discipline Electrical Engineering, Faculty of Engineering) -- Vaal University of Technology / Discomfort glare is a topic that has been investigated for many years without any reasonable explanation regarding its effect on the human visual system. Results of previous research concluded that established methods have a lot of similarities in implementation; but a number of differences when comparing the results of observer's evaluations with the mathematically calculated glare ratings. Therefore, an alternative method of evaluating the influence of exposure to an unshielded light source was investigated to establish a more reliable and realistic response from observers. In order to address the discrepancies of previous evaluation systems concerning observer's varying opinions regarding the level of discomfort experienced, it was decided to investigate the feasibility of evaluating the brain activity of the observers exposed to an unshielded incandescent lamp. This was done in order to facilitate the differences in each individual observer's sensitivity to bright light sources and the influence of personal taste therefore, eliminating the effect of personal interpretation. The main purpose of this study was to determine whether it would be possible to get any response regarding brain functions when an observer is exposed to a bare light source. In order to determine the pathway of visual stimuli it was necessary to investigate the operating principles of the human eye in detail. Because the eye is only an instrument that makes seeing possible; it was also important to investigate the brain and all its different functions. The part of the brain where visual interpretation takes place was indicated as the occipital lobe. This is the part of the brain monitored for any change of functional status by taking measurements with an electroencephalogram (EEG). Measurements were indeed possible; it was presented as a suppression of the alpha brain activity. During the testing procedure it was observed that the observers were not equally photosensitive. There was also a difference in the amount of alpha suppression with the observer's eyes open and closed respectively. Because the alpha rhythm has a tendency to increase with closed eyes it was much easier to notice the suppression.

Thesis (Ph.D. (Physics)) -- University of Limpopo, 2018 / Beyond conventional intercalation chemistry, reaction of lithium with sulphur and oxygen (so-called “Li-air” batteries) have the potential to provide 2 to 5 times the energy density of current Li-ion battery systems. However, both Li/S and Li/O2 systems suffer from cycling performance issues that impede their commercial applications: Li/O2 cycling is limited by electrolyte decomposition and large cell polarization; Li/S suffers from the low conductivity of S and the solubility of intermediary polysulfide species during cycling. It has been reported that Se and mixed SexSy represent an attractive new class of cathode materials with promising electrochemical performance in reactions with both Li and Na ions. Notably, unlike existing Li/S batteries that only operate at high temperature, these new Se and Li/SexSy electrodes are capable of room temperature cycling. Initially, stabilities of insoluble discharge products of oxygen and sulphur in the Li-S and Li-O2 batteries were investigated using density functional theory within the generalized gradient approximation, and these were deduced from their structural, electronic and mechanical properties. The structural properties are well reproduced and agree to within 3% with the available experimental data. Li2S, Li2O and Li2O2 and Li2S2 structures all have negative heats of formations indicating that they are stable, however, that of Li2S2 structure was relatively high compared to others. Calculated phonon dispersion and elastic properties revealed that Li2O, Li2S and Li2O2 structures are mechanically stable and great agreement with experimental work. The Li2S2 structure displayed soft modes associated mainly with sulphur atoms vibrations in the a-b plane, hence it is not mechanically stable in agreement with the negative C13. Stable Li2S2 polymorphs were extracted from soft modes of calculated phonon dispersions along the gamma direction in the Brillioun zone. Temperature is known to have a significant impact on the performance, safety, and cycle lifetime of lithium-ion batteries (LiB). In order to explore properties of discharge products associated with Li/S and Li/Se batteries at different temperatures, molecular dynamics and cluster expansion methods were employed. The former was achieved by firstly deriving empirical interatomic potentials of Li2S and Li2Se which were fitted to experimental and DFT calculated data. The potentials were validated against available experimental and calculated structure, elastic properties and phonon spectra. In addition, complex high temperature transformations and melting of Li2S and Li2Se were reproduced, as deduced from molecular dynamics simulations. Both Li2S and Li2Se were found to withstand high temperatures, up to 1250K each which is a desirable in future advanced battery technologies. Furthermore, cluster expansion and Monte-Carlo simulations were employed to determine phase changes and high temperature properties of mixed Li2S-Se. The former generated 42 new stable multi-component Li2S-Se structures and ranked metastable structures by enthalpy of formation. Monte Carlo simulations produced thermodynamic properties of Li2S-Se system for the entire range of Se concentrations obtained from cluster expansion and it demonstrated that Li2S-Se is a phase separating system at 0K but changes to mixed system at approximately 350K which was confirmed by constructed by phase diagram of Li2S-Se system. It was finally demonstrated that molecular dynamics and Monte Carlo simulations techniques yield consistent results on phase separation and high temperature behavior of Li2S-Se at 50% of sulphur and selenium.

No description available.