The investigation described in this thesis represents the first known attempt to develop a simplified method for the seismic design of structures equipped with a novel friction damping system. The system has been shown experimentally to perform very well and is an exciting development in earthquake resistant design. The design of a building equipped with the friction damping system is achieved by determining the optimum slip load distribution to minimize structural response. A new efficient numerical modelling approach for the analysis and design of Friction Damped Braced Frames (FDBF) is presented. The hysteretic properties of the friction devices are derived theoretically and included in a Friction Damped Braced Frame Analysis Program (FDBFAP), which is adaptable to a microcomputer environment. The optimum slip load distribution is determined by minimizing a Relative Performance Index (RPI) derived from energy concepts. The steady-state response of a single storey friction damped structure subjected to sinusoidal ground motion is investigated analytically. Basic design information on the optimum slip load for the friction device is obtained. The parameters governing the optimum slip load, which minimizes the amplitude for any forcing frequency, are derived. The study indicates that the optimum slip load depends on the characteristics of the ground motion and of the structure. Using variational principles on a shear beam analogy, an optimum slip load distribution along the height of the structure is derived when the total amount of slip load is specified. It is shown that the optimum slip load is proportional to the slope of the deflected shape of the structure. The results of the study reveal that only a small improvement in the response is obtained by using this optimum distribution compared to the response obtained with a uniform distribution. Therefore the use of an optimum uniform distribution seems adequate for the design of friction damped structures. Taking into account the analytical results obtained, FDBFAP is then used in a parametric study which leads to the construction of a design slip load spectrum. The spectrum depends on the properties of the structure and ground motion anticipated at the construction site. It is believed that the availability of this design slip load spectrum will lead to a greater acceptance by the engineering profession of this new and innovative structural concept. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

In late September of 2016, at a United Nations General Assembly, the UN concluded that the biggest threat to human health around the global today is the spread of antibiotic resistant microorganisms, also known as superbugs. The global farmed animal industry is largely responsible for this, as it misuses the antibiotics that were originally designed to save humans from infection by instead using them in vast quantities in animal feed and water. How should the global community respond to this threat?

In applications where resistance to localised corrosion is required, stainless steel alloys containing molybdenum are generally used thanks to their superior resistance to localised attack in aggressive environments. For ferritic stainless steels, vanadium additions have been found to also have a beneficial effect on the resistance to localised corrosion. In this study vanadium and molybdenum were compared directly as alloying elements in 18% chromium ferritic stainless steel as far as their effect on increasing the resistance to localised corrosion is concerned. Pitting potentials in a neutral chloride solution were used as the criterion for qualifying resistance to localised corrosion and it was shown that vanadium gave similar or slightly higher pitting potentials at addition levels of up to 4% (weight percent). It was subsequently found that the mechanism by which the molybdenum and the vanadium increase the resistance to localised corrosion, are not the same. The experimental data for the molybdenum containing alloys corresponded well with other work done in this field. The positive effect of molybdenum additions on the pitting resistance of these alloys could be explained through its effect in lowering the dissolution rate in the active dissolution region by enriching on the dissolving surface. The vanadium additions to these alloys were shown not to have an effect on the active dissolution kinetics. The effect of these two alloying elements on the initiation of metastable pits were examined, but no meaningful advantage for the vanadium containing alloys over the rest could be found. It is suggested that vanadium play a role in changing the dissolution kinetics of the salt film, which forms during the growth of a metastable pit. A delayed dissolution of salt film remnants would lead to a loss of the enriched pit solution, which would cause the metastable pit to repassivate. / Dissertation (M Eng (Metallurgical Engineering))--University of Pretoria, 2007. / Materials Science and Metallurgical Engineering / unrestricted

The aim of this work is the preparation of porous polymeric membranes for liquid separations stable in organic solvents, high temperature and/or extreme acid or basic conditions. Polymeric membranes with these properties could replace more traditional and energy-expensive separation processes like distillation, competing with ceramic membranes due to their easy processability and scalability. A limited library of polymers have been successfully used for decades in water-based applications. They are however unstable in organic solvents without an additional treatment, which is usually a crosslinking reaction. In this dissertation different highperformance polymeric membranes and crosslinking strategies are presented and discussed, allowing their use in harsh environments. We present for the first time the preparation of porous membranes using poly(oxindole) derivatives. These polymers were prepared by superacid catalyzed polyhydroxyalkylation, which is a novel one-pot, room-temperature, metal-free polymerization method. The obtained polymers were fully characterized and then manufactured into membranes by the non-solvent induced phase separation method. The crosslinking of these membranes was achieved by different protocols. First, we reacted the oxindole group in the polymer backbone with a variety of dibromides of different chemical structure. Secondly, we incorporated a propargyl side group, followed by a crosslinking in hot glycerol. Moreover, the strategy of crosslinking using propargyl as pendant group was successfully demonstrated in membranes made of poly(benzimidazole) and poly(triazolebisphenol-AF). And thirdly, we prepared membranes from hydroxyl-functionalized poly(oxindole), and conducted a controlled thermal oxidation, which resulted in the crosslinking by phenoxy radicals. In each case, the resulting membranes achieved insolubility in polar aprotic organic solvents, high resistance in acid medium and had high decomposition temperatures. In each case, the resulting membranes achieved not only insolubility in polar aprotic organic solvents and resistance to acid media but also showed high decomposition temperatures. Finally, we demonstrated for the first time the preparation of porous membranes based on recycled poly(ethylene terephthalate) plastic bottles and their potential application for separations in an organic solvent medium.

京都大学 / 0048 / 新制・論文博士 / 博士(人間健康科学) / 乙第13006号 / 論人健博第1号 / 新制||人健||3(附属図書館) / 32934 / (主査)教授 藤井 康友, 教授 澤本 伸克, 教授 一山 智 / 学位規則第4条第2項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

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Onarm research was conducted in 2011 and 2012 to determine the postemergence and residual control by dicamba of glyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeri S. Wats.). Preemergence dicamba at 0, 0.28, 0.56, and 1.1 kg ae ha-1 and 0.07 kg ae ha-1 flumioxazin was applied at 30, 15 and 0 days prior to planting. Postemergence dicamba at 0.28, 0.56, and 1.1 kg ae ha-1 with and without 0.84 kg ae ha-1 glyphosate was applied to 5, 10 and 15 cm Palmer amaranth. In addition, a greenhouse experiment was conducted in 2012 to evaluate and confirm the optimum rate for control of Palmer amaranth with a new formulation of dicamba (BAS 18322H). In the greenhouse, dicamba at 0.14, 0.28, 0.56, 1.1, and 2.2 kg ae ha-1 was applied to 5, 10, and 15 cm Palmer amaranth.

Background: Multidrug-resistant tuberculosis (MDR-TB) patients receive aminoglycosides as part of their treatment. These drugs are ototoxic, and can cause permanent damage to the cochlea, resulting in a debilitating hearing loss, which has a negative impact on an individual's quality of life. Early detection and management of an ototoxic hearing loss can minimise the impact of the hearing loss on the person's social, emotional, and vocational wellbeing. While patients with MDR-TB are often very ill, it might be ideal to use an objective test that does not require active participation from the patient. In this way, the reliability and validity of the test will not be affected by the patient's state. Distortion product otoacoustic emissions (DPOAEs) at 2f1-f2 are a viable option, as it evaluates cochlear function, specifically the outer hair cells, which are affected first by ototoxic medication. Method: This thesis used a sequential study design aimed to determine the DPOAE stimulus parameters that yield (a) the highest level and the most reliable, sensitive and specific DPOAEs reported in the literature, (b) the highest level and the most reliable DPOAEs in healthy, normally hearing adults, and (c) the most sensitive and specific DPOAEs in participants with MDR-TB patients receiving ototoxic medication. High frequency pure tone audiometry (defined in this thesis as frequencies > 8 kHz) was used as the gold standard. Descriptive statistics, the intraclass correlation coefficient, Pearson's correlation coefficient and mixed model analyses were used to analyse the data. Results: Systematic review: The results of the systematic review indicated an L1/L2 setting of 75/75 dB SPL and f2/f1 value from 1.20 to 1.22 yielded the highest level DPOAEs. The systematic review results for stimulus parameters that yielded the highest test-retest reliability, sensitivity and specificity were inconclusive. Preliminary study with healthy normal hearing participants: The results of the preliminary study in healthy, normal-hearing participants indicated that the highest levels of DPOAEs were elicited with L1/L2 intensity levels of 65/65 and 65/55 dB SPL, and f2/f1 ratios of 1.18, 1.20 and 1.22, as determined by mixed model analyses (p < 0.05). These same stimulus parameters yielded the most reliable DPOAEs in both ears, as determined by intraclass correlation coefficient analysis. Main study with healthy, normal-hearing participants: Descriptive statistics and mixed model analysis showed stimulus intensity levels L1/L2 of 65/55 dB SPL, and f2/f1 ratios of 1.18 and 1.20, elicited the largest DPOAEs. The ratio of 1.20 yielded the largest DPOAEs < 5000 Hz and f2/f1 ratio of 1.18 the largest DPOAEs ≥ 5000 Hz. The second highest DPOAE levels were elicit by L1/L2 = 65/65 dB SPL and f2/f1 = 1.18. The test-retest reliability in this sample was not influenced by changing the stimulus parameters, and DPOAEs were only unreliable at an f2 frequency of 8 000 Hz. Study in participants with MDR-TB: Results in participants with MDR-TB receiving ototoxic medication indicated that the highest levels of DPOAEs were elicited with L1/L2 = 65/55 and an f2/f1 ratio of 1.18 at f2 ≥ 5000 Hz, followed by 65/65 and 1.18. For f2 < 5000 Hz, stimulus intensities of L1/L2 = 65/55 and an f2/f1 ratio of 1.20 yielded the largest DPOAE levels. Relating to sensitivity and specificity, the stimulus parameter combination of 65/55 dB and 1.18 detected the highest number of ears with outer hair cell damage in participants with MDR-TB receiving ototoxic medication. Conclusion: It should be considered to use an f2/f1 ratio of 1.18 for f2 ≥ 5000 Hz and 1.20 for f2 < 5000 Hz when monitoring for ototoxicity, to assist with early identification of outer hair cell damage, in conjunction with high frequency pure tone audiometry. This finding needs to be confirmed in a larger sample of participants with MDR-TB receiving ototoxic medication.

New methods for calculating the stochastic and seismic design response of linear and nonlinear structures are presented. For linear structures, two approaches are developed: (1) the modified mode displacement approach for classically as well as non-classically damped structures, and (2) the generalized force derivative approach for classically damped structures. Both techniques improve the calculation of the pseudostatic contribution of the truncated modes without including them in the analysis. In particular, the modified mode displacement approach is a useful tool for the calculation of seismic design responses affected by the contributions or higher modes. It properly considers the modal correlations as well as the correlation between retained and truncated modes. It is as fast as the mode acceleration method of structural dynamics and it only requires the commonly used ground response spectra employed by the classical mode displacement approach. On the other hand, the generalized force derivative approach requires the input to be defined in terms of its power spectral density function, but it improves even further the estimation of the missing mass effect due to the trucation of modes. For nonlinear structures, the stochastic equivalent linearization technique is employed to develop response spectrum approaches for hysteretic shear buildings and for two dimensional frames with plastic hinges. For this purpose, a generalized modal analysis technique is successfully employed. The proposed response spectrum approaches require the input be defined in terms of the response spectrum of first order oscillators as well as in terms of the commonly used ground response spectra. For shear buildings, the work is extended to include the calculation of floor response spectra. A simulation study is performed to compare the results obtained by the proposed approach. / Ph. D.

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