21 resultados para Ast-89223

em Deakin Research Online - Australia


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This paper investigated the use of titanium dioxide sol-gel coatings to photo-catalyse red wine stains on wool fabrics. Coatings were produced by the hydrolysis and condensation of titanium butoxide (Ti(OC4H9)4) on the surface of wool fabrics after pad application. Coatings were partially converted to the anatase form of titanium dioxide by prolonged immersion in boiling water. The coating presence was confirmed using scanning electron microscopy, UVspectrophotometry and atomic force microscopy. Coated samples were measured for photo-catalytic activity by degrading red wine stains from the surface of the coated fabric. The level of photocatalysis was determined for each of the coating systems after 168 hours. Red wine stains were photo-catalysed and level of staining was reduced from the UV exposed surface of the coated wool fabric.

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An effective wound dressing is not only able to protect the wound area from its surroundings to avoid infection and dehydration, but also to speed up the healing process by providing an optimum microenvironment for healing, removing any excess wound exudates, and allowing continuous tissue reconstruction. In this study, two biodegradable polymers, polycaprolactone (PCL) and polyvinyl alcohol (PVA), were used to electrospin nanofibre membranes. The wound dressing performances of these two membranes were compared with the wound dressing performances of protein coated membranes and conventional non-woven cotton wound dressings. In addition, fibre morphology, porous structural property, mechanical properties of the nanofibre membranes, and their drainage capacity and wound skin histology were examined.

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In our previous work, we have produced a photochromic wool fabric by applying a thin layer of hybrid silica-photochromic dye onto the wool surface. The coating showed a very fast optical response, but had little influence on the fabric handle, however durability was low. In this context, we reported that durability of the hybrid layer can be improved by introducing epoxy groups into the silica matrix via co-hydrolysis and co-condensation of an alkyl trialkoxysilane (ATAS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). The presence of epoxy groups in the silica enhanced both washing and abrasion durabilities. Also, the optical response speed was slightly increased as well. Effects of the type of alkyl silane and the GPTMS:alkyl silane ratio on the coating durability, fabric handle and optical response were examined.

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The city and the urban environment became extremely important in the daily lives of the increasing number of urban populations across the world. Urban research acknowledges that planning urban places should be responsive to the diversity of population. The aim of this paper is to analyse the results of thermal comfort study in the outdoor urban places. The location has been monitored regarding standard comfort variables: air temperature, humidity, wind speed, and globe temperature. The quantitative assessment of comfort conditions was combined with a questionnaire of pedestrians’ thermal comfort perception. In this paper, the analysis of observed thermal sensation with regard to gender and cultural background concerning the sensitivity of different groups to heat and cold is presented.

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Background : Active school transport (AST) has declined rapidly in recent decades. While many studies have examined walking, cycling to school has received very little attention. Correlates of cycling are likely to differ to those from walking and cycling enables AST from further distances. This study examined individual, social and environmental factors associated with cycling to school among elementary school-aged children, stratified by gender.

Methods :
Children (n = 1197) attending 25 Australian primary schools located in high or low walkable neighborhoods, completed a one-week travel diary and a parent/child questionnaire on travel habits and attitudes.

Results : Overall, 31.2% of boys and 14.6% of girls cycled ≥ 1 trip/week, however 59.4% of boys and 36.7% of girls reported cycling as their preferred school transport mode. In boys (but not girls), school neighborhood design was significantly associated with cycling: i.e., boys attending schools in neighborhoods with high connectivity and low traffic were 5.58 times more likely to cycle (95% CI 1.11-27.96) and for each kilometer boys lived from school the odds of cycling reduced by 0.70 (95% CI 0.63-0.99). Irrespective of gender, cycling to school was associated with parental confidence in their child's cycling ability (boys: OR 10.39; 95% CI 3.79-28.48; girls: OR 4.03; 95% CI 2.02-8.05), parental perceived convenience of driving (boys: OR 0.42; 95% CI 0.23-0.74; girls: OR 0.40; 95% CI 0.20-0.82); and child's preference to cycle (boys: OR 5.68; 95% CI 3.23-9.98; girls: OR 3.73; 95% CI 2.26-6.17).

Conclusion : School proximity, street network connectivity and traffic exposure in school neighborhoods was associated with boys (but not girls) cycling to school. Irrespective of gender, parents need to be confident in their child's cycling ability and must prioritize cycling over driving.

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This work has focused on measuring the adhesion forces on both untreated and atmospheric helium plasma treated single jute fibre surfaces using scanning probe microscopy (SPM). The measurements were conducted on three differently aged surfaces for one week, three weeks and six weeks using a standard silicon nitride tip in force-volume (f-v) mode. Up to 256 adhesion data points were collected from various locations on the surface of the studied fibres using in-house developed software and the resulting data were statistically analysed by the histogram method. Results obtained from this analysis method were found to be very consistent with a small statistical variation. The work of adhesion, Wa, was calculated from measured adhesion force using the Johnson–Kendall–Roberts (JKR) and Derjaguin–Muller–Toporov (DMT) models. Increases in both adhesion force and work of adhesion were observed on jute fibre with certain levels of atmospheric plasma treatment and ageing time.

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BACKGROUND : Hydrogen sulfide (H(2)S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H(2)S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H(2)S in carbon tetrachloride (CCl(4))-induced hepatotoxicity, cirrhosis and portal hypertension.

METHODS AND FINDINGS : Sodium hydrosulfide (NaHS), a donor of H(2)S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine γ-lyase (CSE), were applied to the rats to investigate the effects of H(2)S on CCl(4)-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H(2)S, hepatic H(2)S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl(4) significantly reduced serum levels of H(2)S, hepatic H(2)S production and CSE expression. NaHS attenuated CCl(4)-induced acute hepatotoxicity by supplementing exogenous H(2)S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and α-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters.

CONCLUSIONS :  Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension.

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In orthopaedic surgery the reattachment of tendon to bone requires suture materials that have stable and durable properties to allow healing at the tendon-bone interface. Failure rates of this type of surgery can be as high as 25%. While the tissue suture interface is a weak link, proportions of these failures are caused by in-vivo abrasion of the suture with bone and suture anchor materials. Abrasion of the suture material results from the movement of the suture through the eyelet by the surgeon during surgery, or with limb movement after surgery as the suture is not rigidly restrained within the eyelet. During movement the suture is subjected to bending and frictional forces that can lead to fatigue induced failure. This paper investigates the mechanism of bending abrasion fatigue induced failure of number two grade braided sheath only and braided sheath/multifilament core sutures. Sutures were oscillated over a stainless steel wire at low frequency under load in a dry state to simulate the bending and frictional forces between suture and eyelet. Failure mechanism was determined by video microscopy of the suture during abrasion combined with optical microscopy analysis of partially and fully abraded sutures. Braided only structures had high friction loading on the small number of fibres at the abrasion interface. This caused rapid single fibre breakages that accumulate to cause suture failure. The addition of ultra-high molecular weight polyethylene core fibres to a braided suture distributed the applied load across multiple fibres at the abrasion interface. This improved abrasion resistance by 15-20 times that of braided sheath alone.

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Traffic noise causes adverse effects on the health and quality of life of individuals and communities exposed to it, including annoyance, sleep disturbance, decreased performance at school/work, stress, hypertension, and ischemic heart disease. In Australia there are few standards or policies addressing noise in urban environments, with many discrepancies in noise level thresholds when comparing states and regions. Currently Victoria has a day-to-night threshold for noise levels well above accepted levels in Europe, and there is no standard for the late night period. A better understanding of the health impacts of noise in the Australian context is vital for informing development and implementation of policy and legislation for road traffic noise management. This paper reviews the evidence base and policies related to traffic noise in urban areas, and presents a case study of noise mapping and assessing population health impacts (eg. sleep disturbance), in Geelong,Vcitoria,Australia.

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The role of ecology in a sustainable future is prominent in the media, academic writing and political decisions; as such environmental pressures, as well as economic, social and political, increasingly influence planning for the future. This paper looks at how this translates into the process for planning future cities – highlighting gaps in knowledge and issues of implementation. It draws on interdisciplinary sources to explore three main elements of the debate: What is urban ecology and why is it important to sustainable cities?; What gaps are there in the ecological knowledge of planners and policy makers and why are there gaps?; and How can urban ecology be integrated into the planning of future sustainable cities?. This paper does not aim to provide a definitive answer to the problem; rather it addresses the first two areas and identifies potential directions for the third. It takes Australia, as national, Victoria, as regional and Geelong, as local, points of reference.

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Linkages among different construction markets have attracted great of attention from the construction economist. With notable exceptions, most of this infestation has carried out by using input-output analysis. Interactions among regional construction markets have been discussed in few studies and none of them investigate spatial effects on the regional construction markets. This study employed spatial econometric techniques, spatial autocorrelation and convergence tests, to analysis interactions and linkages among construction price indices in Australian six states and two territories. The empirical results indicate the presence of significant positive spatial correlation between the construction prices in Australian eight construction markets and the degree of dependence decrease sufficiently quickly as the space between units increase. The results of convergence test further present evidence on "ripple effect" in the construction prices in Australian regional markets and the changes in regional construction price would positively influence neighboring states first, and then spread out into others, and then the regional prices converge and reach a long-run equilibrium in the following quarters. Urban development policymakers and construction developers could benefit from the analysis of spatial linkages in regional construction markets.

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The turn of the twenty first century heralds a fundamental shift in the world’s population towards cities in what has been termed The Urban Age, most visible in the developing world. Instead of the dichotomy of ‘First World models’ and ‘Third world problems’, research has begun to explore the complexities of urban informality revealing new approaches to the complex creation of urban spaces. This paper will analyse the prevailing perspectives in order to develop an understanding of informality as an urban evolution through necessity. Finally through an analysis of professional urban design experiments the paper highlights opportunities and challenges within the developing world for new and exciting urban design processes in the developed world.

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In this study, fabrics having a superhydrophobic and superoleophobic surface were prepared by a wet-chemistry coating technique using a coating solution containing hydrolyzed fluorinated alkyl silane and fluorinated-alkyl polyhedral oligomeric silsesquioxane. The coating shows remarkable self-healing superhydrophobic and superoleophobic properties and excellent durability against UV light, acid, repeated machine washes, and severe abrasion.

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The United Arab Emirates (UAE) face a serious water problem. It has a very dry climate, high evaporation rate, combined with large water consumption from fast growing population, economic activities and uncontrolled uses of water for irrigation. Currently, UAE has one of the largest water footprints in the world. Groundwater is overexploited. Waste water is increasingly being treated to supply non-drinking water, but it still cover a small proportion of the demand. Desalination of sea water is the main source of potable water in UAE, but the high economic cost of desalination, its intensive energy demand and the adverse effects of its effluents on the marine life are a major concern. Other factors contributing to the problem are the focus of water management policies on keep supplying the growing demand for water, the increase of the per capita water consumption, and the free water charge for most of population. This research goal is to develop a water sustainability set of indicators for the challenging context of UAE. This paper presents the first stage of the research. Based on a review of the literature, the proposed framework involves 19 indicators, divided into four categories: water availability; water quality; water use efficiency; and policy and governance. Using an integrated cause-effect approach (DSR - Driving force, State, Response), the indicators were related in terms of their interdependencies, with a holistic view of the city water cycle. A preliminary test of the indicators to Abu Dhabi as a case study allowed an evaluation of the main 'Driving force' on the system, such as the scarcity of water due to natural constraints of the region, and increasing water consumption patterns of modern society; an assessment of the current 'state', which is under serious water stress. Also it indicated some potential 'responses', such as implementing policies for increasing efficient use.