CHARACTERISTICS AND DESIGN OF DOWNBURST LOADED TRANSMISSION LINES

During the past years, many electrical transmission lines have failed during downbursts. This thesis is part of a research program aimed to understand the behaviour of transmission lines under localized winds. The first part of the thesis assesses the dynamic behaviour of the conductors under downburst loading. A non-linear numerical model is utilized to predict the natural frequencies and mode shapes of the conductors at various loading stages. A turbulence signal is added to the mean component of the downburst wind field previously evaluated from a CFD analysis. Dynamic analysis is performed using various downburst configurations. The second part of the thesis focuses on evaluating the sensitivity of the forces in the members of guyed towers to changes in the downburst configuration, tower height, guys’ configuration, turbulence, and the conductors’ pretensioning force. The axial forces in the members are compared to those resulting from normal wind loading and the broken wire load case. The third part of the thesis focuses on developing simplified loads, equivalent to the critical downburst loads causing the guyed transmission tower to fail. Different options are considered in terms of the location and nature of the design velocity associated to different critical cases. The profile of the horizontal velocity is developed. The equivalent load corresponding to each of the critical cases is developed. Detailed steps of the conductors’ reactions calculations are provided. A loading procedure is developed for designing downburst loaded guyed transmission towers. m The fourth part of the thesis involves studying the behaviour of self supported transmission line towers under downburst loading. A parametric study is performed to determine the critical downburst configurations causing maximum axial forces for various members of the tower. The sensitivity of the internal forces developing in the tower’s members to changes in the downburst size and location is studied. The structural behaviour associated with the critical downburst configurations is described and compared to the behaviour under normal wind loads

Evaluation of human umbilical cord blood as a source of embryonic stem cells

Human umbilical cord blood (HUCB) has been poorly characterised as a source of embryonic stem cells (ESCs). The aim of this study, therefore, was to evaluate HUCB as source of mesenchymal stem cells (MSCs) with embryonic characteristics. HUCB was collected from consenting women undergoing elective caesarean sections. HUCB was meticulously explanted into MesenCult media and incubated. Qualitative and quantitative immunophenotyping of cells was achieved using fluorescein isothiocyanate (FITC) labelled antibodies (CD34, CD45, CD29, CD44, CD73 and CD105) phenotypic markers. Immunocytochemistry was carried out for the human ESC markers CD9, stage-specific embryonic antigen-1 and 4 (SSEA-1 and SSEA-4), E-cadherin, Podocalyxin (PODXL), sex-determining region Y-box 2 (SOX2), NANOG and Octamer (OCT3/4). MSCs were cultured to induce differentiation into adipogenic, osteogenic, chondrogenic and neurogenic cells. Immunocytochemistry was used to identify fatty acid binding protein-4 (FABP-4), osteocalcin, aggrecan, SOX2 and oligodendrocyte-4 (Olig-4) markers. The cells were strongly positive for the MSC markers CD29, CD44, CD73 and CD105; these cells also expressed the ESC markers CD9, SSEA-1 and SSEA-4, E-cadherin, PODXL, SOX2, NANOG and OCT3/4. Additionally, the MSCs expressed the adipogenic FABP-4, osteogenic osteocalcin, chondrogenic aggrecan and neural Olig-4 and SOX2 markers after differentiation. Therefore, HUCB is a rich source for MSCs with embryonic characteristics

A SIGNIFICÂNCIA DISCRIMINATÓRIA ENTRE AQUELES COM ALTA E BAIXA EFICÁCIA ACADÊMICA NO PENSAMENTO ESTRATÉGICO E HÁBITOS DE MENTE ENTRE ESTUDANTES UNIVERSITÁRIAS DO SEXO FEMININO

The current research aimed to identify the discriminatory significance between those with high and low academic efficacy in strategic thinking and productive habits of mind among female university students. For this purpose, the academic efficacy scale, the strategic thinking scale, and the productive habits of mind scale were applied to a sample consisting of (126) female students. The descriptive research approach was utilized due to its suitability to the research nature. Results indicated that there was a low level of strategic thinking among university students, there was a relationship between strategic thinking and productive habits of mind, and there were statistically significant differences between those of high and low academic efficacy in strategic thinking and habits of mind. These results can be utilized in enhancing academic proficiency among university female students and providing planners with practical outcomes that contribute to promoting academic proficiency, strategic thinking, and productive mental habits among university students.A presente pesquisa teve como objetivo identificar a significância discriminatória entre aqueles com alta e baixa eficácia acadêmica no pensamento estratégico e nos hábitos produtivos de mente entre estudantes universitárias do sexo feminino. Para esse fim, foram aplicadas a escala de eficácia acadêmica, a escala de pensamento estratégico e a escala de hábitos produtivos de mente em uma amostra composta por (126) estudantes do sexo feminino. A abordagem de pesquisa descritiva foi utilizada devido à sua adequação à natureza da pesquisa. Os resultados indicaram que havia um baixo nível de pensamento estratégico entre estudantes universitários, havia uma relação entre o pensamento estratégico e os hábitos produtivos de mente, e houve diferenças estatisticamente significativas entre aqueles com alta e baixa eficácia acadêmica no pensamento estratégico e nos hábitos de mente. Esses resultados podem ser utilizados para aprimorar a proficiência acadêmica entre estudantes universitárias e fornecer aos planejadores resultados práticos que contribuam para promover a proficiência acadêmica, o pensamento estratégico e os hábitos mentais produtivos entre os estudantes universitários

Effect of Pelvic Floor Muscle Exercise on Stress Urinary Incontinence Among Women on Pelvic Radiation

Radiation is cornerstone of the treatment of many pelvic tumors. Radiotherapy cause cellular death that benefits cancer control, but can also result in adverse effects such as urinary incontinence. Urinary incontinence is one of the major problems that has an impact on female's quality of life, as it disturbs about one third of adult women worldwide.  Aim: The aim of the study was to examine the effect of pelvic floor muscle exercise on stress urinary incontinence among women on pelvic radiation. Design: A quasi experimental design was utilized for conducting the study. Sample: A sample of 60 adult female participants on pelvic radiation, and had scored more than 10 on the Questionnaire for Urinary Incontinence Diagnosis at Radiology Department in Oncology Unit in one of the biggest teaching hospitals in Cairo, Egypt was recruited, and the sample was randomly divided into study and control groups (30 participants each). Tools: Data were collected using five tools; demographic and medical data sheet, Questionnaire for Urinary Incontinence Diagnosis, The Incontinence Severity Index Scale, Incontinence Impact Questionnaire, and The Incontinence Quiz Scale. Results: There were statistically significant differences regarding quality of symptoms, severity of incontinence, incontinence impact, as well as knowledge regarding stress urinary incontinence in the study group after implementation of the pelvic floor muscle exercise when compared to the control group. Conclusion: the pelvic floor muscle exercise improved the urinary incontinence among participants undergoing pelvic radiation therapy. Recommendation: It is suggested to apply pelvic floor muscle exercise for participants on pelvic radiation therapy in their early course of treatment. Keywords: Pelvic floor muscle exercise, urinary incontinence, stress urinary incontitnce,  pelvic radiation, women

Shear Capacity of RC Beams at Elevated Temperatures

Fire safety is a critical criterion for designing reinforced concrete structures. With the introduction of performance-based design, structural engineers need design tools to assess the capacity of different elements during fire exposure. This paper proposes an analytical method to predict the shear capacity of reinforced concrete beams exposed to elevated temperatures. The proposed method extends the use of existing ambient temperature methods by accounting for the effect of elevated temperatures on material properties. It involves heat transfer analysis, evaluation of the material properties at elevated temperatures, and application of the modified compression field theory to estimate the shear capacity. The method is validated using experimental results by others. A parametric study is then conducted to investigate the effects of different parameters on the shear capacity of reinforced concrete beams exposed to fire

The kinetics of the oxidation of some inorganic species by peroxodisulphate

The reactions of poroxodisulphate with manganese(II), nitrite and chromiurn(III) have been studied in the region of 60&deg;C. In the main introduction a survey is made of published work on the reaction of peroxodisulphate with mainly inorganic substrates. The oxidation of manganese(II) to manganese(IV) was carried out in sulphate media for most of the kinetic investigation. The reaction was found to be first order with respect to peroxodisulphate and zero order with respect to manganese(II). Despite this, however, the observed first order rate constant is greater than that of the thermal decomposition of peroxodisulphate in the absence of manganese(II). The effect of added salts on the rate of the reaction is negligible though the reaction is sensitive to some impurities, added surface and free radical scavengers which all retard it. The activation energy which is 31.5 kcal/mole is only 2 kcal/mole lower than that for the thermal decomposition of peroxodisulphate alone. A chain mechanism consistent with the observed kinetics is proposed. The oxidation of nitrite was carried out in phosphate media. The redox reaction is of the second order, being first order with respect to each reactant. Cations catalyze the reaction and the extent of catalysis depends on the nature and concentration of cation. The activation energy for the redox reaction is 14 kcal/mole. E.s.r. spectroscopy did not reveal any stable or detectable free radicals. Reaction mechanisms are proposed. The peroxodisulphate-chromium(III) reaction was carried out in acid-perchlorate media and acid-sulphate media. The oxidation of chromium(III) to chromium(VI) is faster in the second medium than in the first.<p