Water lubricated bearings

The increasing ecological awareness and stringent requirements for environmental protection have led to the development of water lubricated bearings in many applications where oil was used as the lubricant. The chapter details the theoretical analysis to determine both the static and dynamic characteristics,including the stability (using both the linearised perturbation method and the nonlinear transient analysis) of multiple axial groove water lubricated bearings. Experimental measurements and computational fluid dynamics (CFD) simulations by the Tribology research group at Queensland University of Technology,Australia and Manipal Institute of Technology, India, have highlighted a significant gap in the understanding of the flow phenomena and pressure conditions within the lubricating fluid. An attempt has been made to present a CFD approach to model fluid flow in the bearing with three equi-spaced axial grooves and supplied with water from one end of the bearing. Details of the experimental method used to measure the film pressure in the bearing are outlined. The lubricant is subjected to a velocity induced flow (as the shaft rotates) and a pressure induced flow (as the water is forced from one end of the bearing to the other). Results are presented for the circumferential and axial pressure distribution in the bearing clearance for different loads, speeds and supply pressures. The axial pressure profile along the axial groove located in the loaded part of the bearing is measured. The theoretical analysis shows that smaller the groove angle better will be the load-carrying capacity and stability of these bearings. Results are compared with experimentally measured pressure distributions.

The effect of a high fat meal on postprandial arterial stiffness in men with obesity and type 2 diabetes

Context: Postprandial dysmetabolism is emerging as an important cardiovascular risk factor. Augmentation index (AIx) is a measure of systemic arterial stiffness and independently predicts cardiovascular outcome. Objective: The objective of this study was to assess the effect of a standardized high-fat meal on metabolic parameters and AIx in 1) lean, 2) obese nondiabetic, and 3) subjects with type 2 diabetes mellitus (T2DM). Design and Setting: Male subjects (lean, n = 8; obese, n = 10; and T2DM, n = 10) were studied for 6 h after a high-fat meal and water control. Glucose, insulin, triglycerides, and AIx (radial applanation tonometry) were measured serially to determine the incremental area under the curve (iAUC). Results: AIx decreased in all three groups after a high-fat meal. A greater overall postprandial reduction in AIx was seen in lean and T2DM compared with obese subjects (iAUC, 2251 +/- 1204, 2764 +/- 1102, and 1187 +/- 429% . min, respectively; P < 0.05). The time to return to baseline AIx was significantly delayed in subjects with T2DM (297 +/- 68 min) compared with lean subjects (161 +/- 88 min; P < 0.05). There was a significant correlation between iAUC AIx and iAUC triglycerides (r = 0.50; P < 0.05). Conclusions: Obesity is associated with an attenuated overall postprandial decrease in AIx. Subjects with T2DM have a preserved, but significantly prolonged, reduction in AIx after a high-fat meal. The correlation between AIx and triglycerides suggests that postprandial dysmetabolism may impact on vascular dynamics. The markedly different response observed in the obese subjects compared with those with T2DM was unexpected and warrants additional evaluation.

Sustainable urban stormwater management : water sensitive urban design perceptions, drivers and barriers

Stormwater has been recognised as one of the main culprits of aquatic ecosystem pollution and as a significant threat to the goal of ecological sustainable development. Water sensitive urban design is one of the key responses to the need to better manage urban stormwater runoff, the objectives of which go beyond rapid and efficient conveyance. Underpinned by the concepts of sustainable urban development, water sensitive urban design has proven to be an efficient and environmentally-friendly approach to urban stormwater management, with the necessary technical know-how and skills already available. However, large-scale implementation of water sensitive urban design is still lacking in Australia due to significant impediments and negative perceptions. Identification of the issues, barriers and drivers that affect sustainability outcomes of urban stormwater management is one of the first steps towards encouraging the wide-scale uptake of water sensitive urban design features which integrate sustainable urban stormwater management. This chapter investigates key water sensitive urban design perceptions, drivers and barriers in order to improve sustainable urban stormwater management efforts.

Sustainable water provision : challenges, alternative strategies and sources in the ERA of climate change

As a result of rapid urbanisation, population growth, changes in lifestyle, pollution and the impacts of climate change, water provision has become a critical challenge for planners and policy-makers. In the wake of increasingly difficult water provision and drought, the notion that freshwater is a finite and vulnerable resource is increasingly being realised. Many city administrations around the world are struggling to provide water security for their residents to maintain lifestyle and economic growth. This chapter reviews the global challenge of providing freshwater to sustain lifestyles and economic growth, and the contributing challenges of climate change, urbanisation, population growth and problems in rainfall distribution. The chapter proceeds to evaluate major alternatives to current water sources such as conservation, recycling and reclamation, and desalination. Integrated water resource management is briefly looked at to explore its role in complementing water provision. A comparative study on alternative resources is undertaken to evaluate their strengths, weaknesses, opportunities and constraints, and the results are discussed.

Traffic and climate change impacts on water quality : measuring build-up and wash-off of heavy metals and petroleum hydrocarbons

Understanding the impacts of traffic and climate change on water quality helps decision makers to develop better policy and plans for dealing with unsustainable urban and transport development. This chapter presents detailed methodologies developed for sample collection and testing for heavy metals and total petroleum hydrocarbons, as part of a research study to investigate the impacts of climate change and changes to urban traffic characteristics on pollutant build-up and wash-off from urban road surfaces. Cadmium, chromium, nickel, copper, lead, iron, aluminium, manganese and zinc were the target heavy metals, and selected gasoline and diesel range organics were the target total petroleum hydrocarbons for this study. The study sites were selected to encompass the urban traffic characteristics of the Gold Coast region, Australia. An improved sample collection method referred to as ‘the wet and dry vacuum system’ for the pollutant build-up, and an effective wash-off plan to incorporate predicted changes to rainfall characteristics due to climate change, were implemented. The novel approach to sample collection for pollutant build-up helped to maintain the integrity of collection efficiency. The wash-off plan helped to incorporate the predicted impacts of climate change in the Gold Coast region. The robust experimental methods developed will help in field sample collection and chemical testing of different stormwater pollutants in build-up and wash-off.

Synthesis and characterisation of layered double hydroxides and their application for water purification

Layered doubly hydroxides (LDHs) also known as hydrotalcites or anionic clays are a group of clay minerals that have shown promise for the removal of toxic anions from water through both anion exchange and a process known as the reformation effect. This project has involved the preparation and characterisation of LDH materials as well as the investigation of their ability to remove selected anions from aqueous solutions by the reformation effect. The LDH materials were successfully prepared from magnesium, aluminium, zinc and chromium chloride salts using the co-precipitation method. Samples were characterised using powder X-ray diffraction (XRD) and thermogravimetry (TG) to confirm the presence of LDHs. Powder XRD revealed a characteristic LDH structure for all LDH samples. Thermal Analysis showed decomposition usual occurred through a three or four step process as expected for LDHs. Preliminary investigations of the removal of sulfate, nitrate and fluoride by an Mg/Al LDH were carried out, and the products were characterised using XRD and TG which showed that an LDH material similar to the original hydrotalcite was formed after reformation. A Zn/Al LDH was investigated as a potential sorbent material for the removal of iodine and iodide from water. It was found that the LDH was a suitable adsorbent which is able to remove almost all of the iodine present in the test solutions. Again, the products were characterised by XRD, TG and evolved gas mass spectrometry (EGMS) in an attempt to better understand the iodine removal process. Powder XRD showed successful reformation of the LDH structure and TG/EGMS showed that only a small amount of iodine species were lost during thermal decomposition. Finally, the mineral stichtite a Mg/Cr LDH was successfully synthesised and investigated using XRD, TG and EGMS. Unfortunately, due to lack of time it was not possible to identify any new uses for the mineral stichtite in the current project.

Promotion and succession management and associated retention issues in Australian law firms

The focus of this research was promotion and succession management in Australian law firms. Two staff retention issues currently faced by the Australian legal industry were identified as suggesting possible failures in this area: 1) Practitioners are leaving law firms early in their careers, 2) Female representation is disproportionally low at partnership level. The research described current Australian law firm promotion and succession practices and then explained their possible relevance to the two retention issues. The overall aim of the research was to uncover key findings and present practical recommendations to law firm managers and partners ready for incorporation into their future promotion and succession planning practice. In so doing the research aimed to benefit the Australian legal community as a whole. Four areas of literature relevant to the topic were reviewed, 1) law firm governance concluding that the fundamental values of the P²-Form remained constant (Cooper, Hinings, Greenwood & Brown, 1996; Morris & Pinnington, 1998) with ownership and strategic control of law firms remaining in the hands of partners; 2) the importance of individual practitioners to law firms concluding that the actual and opportunity costs relating to practitioner turnover were significant due to the transient nature of knowledge as a key asset of law firms (Gottschalk & Khandelwal, 2004; Rebitzer & Taylor, 2007); 3) generational differences concluding with support for the work of Finegold, Mohrman and Spreitzer (2002), Davis, Pawlowski and Houston (2006), Kuhnreuther (2003), and Avery, McKay, and Wilson (2007) which indicated that generational cohort differences were of little utility in human resources management practice; and 4) previous research relating to law firm promotion and succession practices indicating that five practices were relevant in law firm promotion outcomes; 1) firm billing requirements (Gorman & Kmec, 2009; Phillips, 2001; Noonan & Corcoran, 2004; Webley & Duff, 2007); 2) mentoring programs (Phillips, 2001; Noonan & Corcoran, 2004); 3) the existence of female partners (Gorman & Kmec, 2009; Beckman & Phillips, 2005); 4) non-partner career paths (Phillips, 2001; Corcoran & Noonan, 2004); and 5) the existence of family friendly policies (Gorman & Kmec, 2009; Phillips, 2001; Noonan & Corcoran, 2004; Webley & Duff, 2007.) The research was carried out via a sequential mixed method approach. The initial quantitative study was based upon a theoretical framework grounded in the literature and provided baseline information describing Australian law firm promotion and succession practices. The study was carried out via an on-line survey of Australian law firm practitioners. The results of the study provided the basis for the second qualitative study. The qualitative study further explained the statistically generated results and focused specifically on the two identified retention issues. The study was conducted via one-on-one interviews with Australian law firm partners and experienced law firm managers. The results of both studies were combined within the context of relevant literature resulting in eight key findings: Key findings 1) Organisational commitment levels across generational cohorts are more homogenous than different. 2) Law firm practitioners are leaving law firms early in their careers due to the heavy time commitment behaviour demanded of them, particularly by clients. 3) Law firm promotion and succession practices reinforce practitioner time commitment behaviour marking it as an indicator of practitioner success. 4) Law firm practitioners believe that they have many career options outside law firms and are considering these options. 5) Female practitioners are considering opting out of law firms due to time commitment demands related to partnership conflicting with family commitment demands. 6) A masculine, high time commitment culture in law firms is related to the decision by female practitioners to leave law firms. 7) The uptake of alternative work arrangements by female practitioners is not fatal to their partnership prospects particularly in firms with supportive policies, processes and organisational culture. 8) Female practitioners are less inclined than their male counterparts to seek partnership as an ultimate goal and are more likely to opt out of law firms exhibiting highly competitive, masculine cultures. Practical recommendations Further review of the data collected in relation to the key findings provided the basis for nine practical recommendations specifically geared towards implementation by law firm managers and partners. The first recommendation relates to the use of generational differences in practitioner management. The next six relate to recommended actions to reduce the time commitment demands on practitioners. The final two recommendations relate to the practical implementation of these actions both at an individual and organisational level. The recommendations are as follows: 1) "Generationally driven," age based generalisations should not be utilised in law firm promotion and succession management practice. 2) Expected levels of client access to practitioners be negotiated on a client by client basis and be included in client retention agreements. 3) Appropriate alternative working arrangements such as working off-site, flexible working hours or part-time work be offered to practitioners in situations where doing so will not compromise client serviceability. 4) The copying of long working hour behaviours of senior practitioners should be discouraged particularly where information technology can facilitate remote client serviceability. 5) Refocus the use of timesheets from an employer monitoring tool to an employee empowerment tool. 6) Policies and processes relating to the offer of alternative working arrangements be supported and reinforced by law firm organisational culture. 7) Requests for alternative working arrangements be determined without regard to gender. 8) Incentives and employment conditions offered to practitioners to be individualised based on the subjective need of the individual and negotiated as a part of the current employee performance review process. 9) Individually negotiated employment conditions be negotiated within the context of the firm’s overall strategic planning process. Through the conduct of the descripto-explanatory study, a detailed discussion of current law firm promotion and succession practices was enabled. From this discussion, 7 eight key findings and nine associated recommendations were generated as well as an insight into the future of the profession being given. The key findings and recommendations provide practical advice to law firm managers and partners in relation to their everyday promotion and succession practice. The need to negotiate individual employee workplace conditions and their integration into overall law firm business planning was put forward. By doing so, it was suggested that both the individual employee and the employing law firm would mutually benefit from the arrangement. The study therefore broadened its practical contribution from human resources management to a contribution to the overall management practice of Australian law firms. In so doing, the research has provided an encompassing contribution to the Australian legal industry both in terms of employee welfare as well as firm and industry level success.

Sources of hydrochemical variability and implications associated with CSG water extraction

Coal Seam Gas (CSG) production is achieved by extracting groundwater to depressurize coal seam aquifers in order to promote methane gas desorption from coal micropores. CSG waters are characteristically alkaline, have a neutral pH (~7), are of the Na-HCO3-Cl type, and exhibit brackish salinity. In 2004, a CSG exploration company carried out a gas flow test in an exploration well located in Maramarua (Waikato Region, New Zealand). This resulted in 33 water samples exhibiting noteworthy chemical variations induced by pumping. This research identifies the main causes of hydrochemical variations in CSG water, makes recommendations to manage this effect, and discusses potential environmental implications. Hydrochemical variations were studied using Factor Analysis and this was supported with hydrochemical modelling and a laboratory experiment. This reveals carbon dioxide (CO2) degassing as the principal source of hydrochemical variability (about 33%). Factor Analysis also shows that major ion variations could also reflect changes in hydrochemical composition induced by different pumping regimes. Subsequent chloride, calcium, and TDS variations could be a consequence of analytical errors potentially committed during laboratory determinations. CSG water chemical variations due to degassing during pumping can be minimized with good completion and production techniques; variations due to sample degassing can be controlled by taking precautions during sampling, transit, storage and analysis. In addition, the degassing effect observed in CSG waters can lead to an underestimation of their potential environmental effect. Calcium precipitation due to exposure to normal atmospheric pressure results in a 23% increase in SAR values from Maramarua CSG water samples.

Understanding treatment characteristics of constructed stormwater wetlands

Constructed wetlands are a common structural treatment measure employed to remove stormwater pollutants and forms an important part of the Water Sensitive Urban Design (WSUD) treatment suite. In a constructed wetland, a range of processes such as settling, filtration, adsorption, and biological uptake play a role in stormwater treatment. Occurrence and effectiveness of these processes are variable and influenced by hydraulic, chemical and biological factors. The influence of hydraulic factors on treatment processes are of particular concern. This paper presents outcomes of a comprehensive study undertaken to define the treatment performance of a constructed wetland highlighting the influence of hydraulic factors. The study included field monitoring of a well established constructed wetland for quantity and quality factors, development of a conceptual hydraulic model to simulate water movement within the wetland and multivariate analysis of quantity and quality data to investigate correlations and to define linkages between treatment performance and influential hydraulic factors. Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP) concentrations formed the primary pollutant parameters investigated in the data analysis. The outcomes of the analysis revealed significant reduction in event mean concentrations of all three pollutants species. Treatment performance of the wetland was significantly different for storm events above and below the prescribed design event. For events below design event, TSS and TN load reduction was comparatively high and strongly influenced by high retention time. For events above design event, TP load reduction was comparatively high and was found to be influenced by the characteristics of TP wash-off from catchment surfaces.

Performance characterisation of a constructed wetland

Performance of a constructed wetland is commonly reported as variable due to the site specific nature of influential factors. This paper discusses outcomes from an in-depth study which characterised treatment performance of a wetland based on the variation in runoff regime. The study included a comprehensive field monitoring of a well established constructed wetland in Gold Coast, Australia. Samples collected at the inlet and outlet was tested for Total Suspended Solids (TSS), Total Nitrogen (TN) and Total Phosphorus (TP). Pollutant concentrations in the outflow were found to be consistent irrespective of the variation in inflow water quality. The analysis revealed two different treatment characteristics for events with different rainfall depths. TSS and TN load reduction is strongly influenced by hydraulic retention time where performance is higher for rainfall events below the design event. For small events, treatment performance is higher at the beginning of the event and gradually decreased during the course of the event. For large events, the treatment performance is comparatively poor at the beginning and improved during the course of the event. The analysis also confirmed the variable treatment trends for different pollutant types.