Automotive engine mounts are used to support engine weight, protect engine from road inputs and isolate transmission of vibrations created by the engine, which has a drastic effect on the noise generated inside the passenger cabin. Most common types of engine mounts are elastomeric and hydraulic mounts, the former having better vibration isolation characteristics whereas the latter displays better shock isolation. Elastomeric mounts are widely used for their low initial cost, while hydraulic mounts with inertia track and decoupler are chosen for their good vibration isolation and shock excitation characteristics. However, hydraulic mounts with inertia track and decoupler are not appropriate for small segment and commercial vehicles due their high initial cost. In this thesis, the effect of the addition of a dry friction damper on the performance of elastomeric automobile engine mounts is investigated. Friction dampers are used to attenuate vibration amplitudes in many applications such as gas turbine engines, railway vehicles, space structures and civil buildings. In this study, a friction element is added to the engine mount at its axial direction and its effect is studied. Results show that, the addition of dry friction damping to the original system increases vibration isolation performance significantly at low frequencies / whereas, due to the increased stiffness of the system, at high frequencies dry friction damper has a mitigating effect on performance. In order to overcome this problem, original system parameters are modified. In the modified system a softer mount that increase vibration isolation performance at high frequencies / but, which might cause excessive static deflection due to reduced stiffness of the system is used. On the other hand, addition of dry friction damping prevents excessive static deflections due to the increased stiffness effect and also increases the performance at high frequencies due to the soft mount. Final results showed that vibration isolation performance at low frequencies increases considerably while vibration isolation performance at high frequency is similar and even slightly better than the original system with addition of dry friction damping.

The McMurdo Dry Valleys comprise some 4,800km2 of ice-free terrain in east Antarctica and this constitutes the coldest and most arid desert on Earth. The ecosystem of the Dry Valleys is characterized by microbial processes since environmental extremes severely limit higher plant and animal life. A major international collaborative research effort co-ordinated by the International Center for Terrestrial Antarctic Research (ICTAR), identified long-term study sites representative of maritime and inland Dry Valleys environments. The maritime site, Miers Valley, has been the subject of intensive multi-disciplinary study in recent years, of which the work in this thesis is a part. Previous studies have identified soil microbial communities and their putative functional roles, but lithic communities have not been previously appreciated. This thesis reports aspects on the biodiversity and ecology of lithic microbial communities in Miers Valley. A survey of terrain revealed extensive weathered granite, but no porous sandstone or limestone rocks more commonly associated with cryptoendolithic communities (those colonizing pore spaces within rock substrates). Granite was extensively colonized (30-100% of available substrate) by chasmoendolithic microorganisms (colonizing cracks and fissures in weathered rock). Visual examination of colonized rocks revealed a distinct zone of biomass 2-5mm below the rock surface, and this was overlain by a weathered and friable matrix of rock. Microscopy revealed a community dominated by diverse cyanobacterial morphotypes, plus other unidentifiable microbes of varied morphology. A quantitative approach to broad-scale community fingerprinting was adopted, utilizing terminal restriction fragment length polymorphism (TRFLP) and sequence based identifications of restriction fragments. The multi-domain approach encompassed Archaea, Bacteria and Eukarya. The results revealed relatively low species richness (0.6-1.8) for each domain with community richness estimates also relatively low (<3). Nonetheless very clear and statistically supported patterns in the occurrence of phylotypes within chasmolithic communities were related to aspect (which strongly affects temperature and moisture availability in Dry Valleys locations). The bacterial assemblages formed two groups (cold-dry south facing slopes and valley floor moraine). The eukaryal assemblages also formed two groups although here the moraine samples grouped with the warmer wetter north facing slope and the cold-dry south facing slope assemblages formed a separate group. The archaeal assemblages displayed no difference within different valley terrain. Extensive sequence based interrogation of community structure using clone libraries revealed a community dominated by cyanobacteria, Actinobacteria, Deinococci and putative lichens. These phyla are all known for their extreme tolerance to desiccation and occurrence in arid landscapes. Phylogenetic analysis revealed that these abundant taxa shared close affiliation with those from other Antarctic refuge niches such as hypoliths and cryptoendoliths. The cyanobacteria were mainly Oscillatoriales, but other genera such as Chroococcidiopsis and Nostoc commonly recovered in hot desert lithic communities were generally absent. The eukaryal community was dominated by chlorophyte algae, whilst the archaeal phylotypes were a diverse collection spanning both euryachaeal and crenarchaeal lineages. Overall the data revealed the chasmoendolithic community in Miers Valley was widespread and with relatively restricted diversity. The selection pressures related to topology of the valley have resulted in different community structure within the valley. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

This study is an exposition of research into the effect of operational efficiency to global competitiveness, with the Richards Bay Dry Bulk Terminal (DBT) being the case study. The Richards Bay DBT is the main dry bulk terminal in the South African ports, operated by Transnet Ports Terminals (TPT), which is a division of the state-owned Transnet Ltd. Because of the strategic position of the DBT as the main dry bulk terminal of the country and also that it is a state owned entity, its competitiveness or otherwise is a reflection of South Africa the country as a trade destination. The research seeks to investigate the problem of the declining volumes handled by the DBT, which is traced to the possible operational inefficiencies and is likely to impede competitiveness of the DBT. While this study will not propose the ultimate solutions to the DBT’s problems, it will identify the root causes and symptoms of the problems, which will ultimately guide what needs to be tested as a better solution. Based on this, it is argued that this topic should generate a lot of interest to the stakeholders both locally and internationally.

The first part of this thesis examines the psychosocial characteristics of a cohort oj 270 bedwetting children attending a community enuresis service for treatment These children were recruited to a stratified cluster randomised controlled trial which forms the second part of this thesis in which additional information wa~ provided via a multimedia computer program and written leaflets. The mail clinical outcome measures were becoming dry and remaining dry six months pos discharge, time to dry, non-attendance and dropout rates. The main psycho socia measures were maternal tolerance, the impact of bedwetting and self-esteem. Th theoretical basis for the intervention(s) was the 'incomplete learning' model c bedwetting.' It was hypothesised that the intervention (s) would improve the sell efficacy of children through the mediation of cognitive, motivational, affectiv and self-selection changes (Bandura 1977). The randomisation procedure was slightly biased with children in the comput( group being sampled from a more affluent population and those in tl control/leaflets group from a more deprived population. There were also few, children from minority ethnic groups in the computer group. Significa differences were found between the ethnic groups in response to the impact bedwetting and maternal tolerance scales, together with parents' reports of th{ child's distress and parental worry. Therefore analysis was conducted on a samI matched by Jarman scores which excluded the children from affluent areas in t computer group and children from deprived areas in the control and leaflets grm Analysis was also conducted on the entire cohort. Bedwetting children had a lower self-esteem than school children. However, selfesteem improved with treatment with the greatest changes occurring for those who became dry. Low self-esteem was significantly related to a high impact of bedwetting. The presence of housing difficulties produced the least positive response on the psychosocial measurement scales. Low parent reported child distress and less severe wetting at initial assessment predicted a successfu: outcome. Although self-esteem was significantly lower for bedwetting children compared t( the school children the mean difference of less than one item suggests this result i not clinically meaningful. Nevertheless there are clearly some bedwettinJ children with less positive psychosocial and clinical situations. Bedwetting seem to be worse psychosocially for children from less affluent backgrounds, measure by the presence of housing difficulties, and those who are most distressed by it ne only have a lower self-esteem, but they are less likely to get dry. Howeve children's self-esteem does improve with treatment. The intervention( s) made no significant difference to any of the clinical outcorr measures or any of the psychosocial measures recorded during and post-treatmel for either the matched sample or the entire cohort. The absence of an intervention effect is disappointing and suggests that it is n sufficient merely to provide novel additional information to bedwetting childre Two main problems with the study design were identified. The large variation bedwetting children's time to dry suggests the outcome measures used may not sufficiently precise to detect a difference if one was present. The computer and the leaflets may have had insufficient power to produce changes in children at the level measured. Future research might wish to use a more intensive program where the computer intervention is combined with the leaflets. Nevertheles~ whilst this intensive training input and measurement is likely to motivate somt children this will not be the case for all.

Enhanced oil recovery by dry forward in-situ combustion has been studied in a combustion tube. Twelve experiments are reported exploring the effects of three factors: oxygen flow, partial pressure and mole fraction, each factor at two levels. The pressures used went up to 790 kPa, and the oxygen mole fraction to 35%. It was discovered that the oxygen partial pressure had no statistically significant effect. The oil recovery was independent of the factors used. The combustion time was dominated by the oxygen flow, as were the reaction rates, while fuel and oxygen consumption depended mainly on the oxygen mole fraction. Increasing the oxygen mole fraction reduced the consumption figures. The reaction stoichiometry was substantially independent of the three factors. It was also found that the total pressure had no statistically significant effect on oil recovery, combustion time, reaction rates, fuel consumption or stoichiometry. The oil produced by the in-situ combustion process tended to be of lower viscosity and density than the original oil. Oil-water emulsions were produced which could not be broken. The experiments were controlled by a computer, and the PID control algorithms and associated equipment proved succesful. Linked in with the control routines was a model of the process to calculate fluid saturations and flows during the course of the experiment. Measured information was used directly in the mass and energy balances. The resultant fluid saturations supplied a reasonable match with experimental oil saturations from two experiments that were stopped early. The computed liquid production histories also matched up well with the experimental results. The oil saturations from the numerical model were used in developing a robust method for calculating reaction constants from the experimental data. A simplified surface-reaction scheme was used involv~ng low-temperature oxidation and fuel burnoff to explain the effects of flow, pressure and oxygen mole fraction on the process.

In order to understand the ecological characteristics of three dry farming systems in the semiarid San Luis Potosi Plateau, Mexico, a one year study was conducted. The systems studied were a purely rainfed field, a field on an alluvial fan irrigated with runoff water, and a field in a bottomland irrigated with water diverted from an ephemeral stream. Three treatments, farmed, edge and unfarmed, were established in a Randomized Block design, with three replications, for each system. The major conclusions of this research were the following. During the summer, climate is resposible for a concentration of the communities's production and reproduction. Climate is also of paramount importance to agriculture. Rainy periods, on the other hand, decreased the activity of animals. None of the farming systems had detrimental effect on soil fertility. Only slight modifications of soil temperature and air temperature and humidity resulted from farming. A general overview of all the results did not provide evidence that all farming systems decrease biotic richness and diversity. The effects depended on the type of system, its isolation, and the natural vegetation adjacent to it. Herbs were enhanced by farming only when the natural system was relatively free of them. Farming did not have important effects on invertebrates. Birds were negativelly affected by farming, whenever the unfarmed areas included an arboreal stratum. Also, insectivorous birds responded differently than non-insectivores. Rodents were affected negatively by farming in two of the systems, and this could be linked to habitat simplicity. In one case, dense herb cover was associated with very high rodent populations. In general the data adjusted to the hypothesis that structurally more heterogeneous agroecosystems hold more diverse biotas. The concepts of "farmland biota" and "edge effect" were not supported by this study. Edges were ocasionally superior, and only when they included more complex plant communities than either side. A mosaic of heterogeneous farmlands and natural vegetation attracts certain rodents and birds, increasing environmental diversity.

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No description available.

The key aims of this project were: (i) investigation of atmospheric nitrogen deposition, focused on discrimination between bulk, wet and dry deposition, and between particulate matter and gas phase, (ii) accurate quantification of the contributions of dissolved organic and inorganic nitrogen to each type of deposition, and (iii) exploration of the origin and potential sources of atmospheric water soluble organic nitrogen (WSON). This project was particularly focused on the WSON fraction because, despite it being a potentially important source of bioavailable reactive nitrogen, a number of questions regarding its deposition mechanism (wet vs. dry), composition and origin (natural, anthropogenic or mixed) remain unanswered. There are two major difficulties in WSON determination: (i) the diversity of organic nitrogen compounds compared with the inorganic forms, and (ii) the lack of a direct determination method: the derivation of organic nitrogen concentrations in an aqueous sample involves the determination of the dissolved inorganic nitrogen (DIN) species concentration, comprising nitrate and ammonium, the determination of the total dissolved nitrogen (TDN) concentration, and the subtraction of the DIN concentrations from the TDN concentration. TDN determination requires a preparatory digestion step: high-temperature catalytic oxidation was the method used in this study. Ion chromatography (IC) was the method of choice for nitrate determination, whilst ammonium determination was by IC for rain samples, and by flow injection analysis for air samples collected into aqueous media. This thesis is structured in 3 main parts: the first part examines weekly rain data over a period of 22 months from June 2005 to March 2007 collected in 2 types of rain collector (bulk deposition and “dry+wet” deposition) located in a semi-rural area 15 km southwest of Edinburgh, UK (N55°51′44″, W3°12′19″). Bulk deposition collectors were the standard rain gauges used in the UK national network for monitoring precipitation composition. “Dry+wet” deposition collectors were flushing rain gauges equipped with a rain detector, a spray nozzle, a 2-way valve and two independent bottles to collect funnel washings (dry deposition) and true wet deposition. A key objective in this part of the work was the accurate quantification of inorganic and organic water-soluble nitrogen species contribution to each type of deposition. On average, for the 27 weekly samples with 3 valid replicates for the 2 types of collectors, DON represented 23% of the TDN in bulk deposition. Dry deposition of particles and gas on the funnel surface, rather than rain, contributed over half of all N-containing species (inorganic and organic). Some discrepancies were found between bulk and flushing rain gauges, for deposition of both TDN and DON, suggesting biological conversion and loss of inorganic N in the flushing samplers. The second stage of this project was the investigation of in situ atmospheric concentrations of WSN species, both organic and inorganic. Simultaneous daily measurements of ammonium, nitrate and WSON were made between July and November 2008 at the same semi-rural site in south-east Scotland. Discrimination between material from the gas and particle phases was achieved by means of Cofer scrubbers and PTFE membrane filters, respectively. Average concentrations of NH3 (determined as NH4+), NO2/HNO3 (determined as NO3-) and WSON in the gas phase were 82 ± 54 nmol N m-3, 2.6 ± 2.5 nmol N m-3 and 18 ± 12 nmol N m-3 respectively, and in the particle phase were 20 ± 24 nmol N m-3, 10 ± 9 nmol N m-3 and 8 ± 7 nmol N m-3 respectively (± represent standard deviation across all valid daily samples, not error of triplicate samples). Except for oxidised inorganic N, average concentrations in the gas phase were larger than in the particle phase. No evidence of solely agricultural or solely combustion sources of WSON was found, as no correlation in either phase between WSON and either NH4+ or NO3- could be established. The final stage of this project was to gain a broader picture of nitrogen deposition across Europe. Rain samples were analysed for TDN and DIN from a network of 21 different sampling locations, from the south of Portugal to the north of Finland. The average DON contribution across the 21 sampling sites was ~ 19% and, according to the data gathered in this study, DON species appeared largely unrelated specifically to agricultural or to combustion nitrogen sources, although the results varied widely from site to site. Overall, this work has shown that ON and its deposition comprises a significant component of total atmospheric reactive nitrogen.

The purpose of this study is to examine the impact of a previous attitude toward an, issue (i.e., liquor-by- the drink in the state of Texas) on the perception of messages concerning that issue.