959 resultados para reclaimed rubber
Resumo:
The current work compares some slurry pump lab wear results with the wear found across different field applications with d85 particle size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for particles larger than d8The current work compares some slurry pump lab wear results with the wear found across different field applications with d85 particle 10 size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different 11 material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle 12 size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are 13 also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab 14 tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for 15 particles larger than d85 of about 700mm. © 2001 Elsevier Science B.Y. All rights reserved.
Resumo:
Wastewater reuse is being widely promulgated to help address the global freshwater resource crisis. It can assist in reducing extraction of freshwater from the environment, and reuse of wastewater lessens the need for environmental discharge, which is clearly beneficial to receiving waters. But the practice itself also has the potential to be detrimental to natural and human environments: soil structure can become degraded, aquifers may be polluted, and human health may be threatened. The challenge facing natural resource managers is to identify the potential benefits and risks, and to achieve an appropriate balance. This paper describes environmental benefits and threats concomitant with the reuse of wastewater. We frequently draw upon examples from China and Australia-two countries that face particularly daunting water resource
challenges-but the principles can be.extended far beyond these geographical bounds and are applicable to
many parts of the world.
Resumo:
In industrial polymer and synthetic rubber production facilities, workers are exposed to 1,3-butadiene. This compound is converted in vivo to 1,2,3,4-diepoxybutane (DEB) and has been linked to increased incidences of cancer in these individuals. Carcinogenesis has been attributed to formation of DEB induced DNA interstrand cross-links. Previous studies have demonstrated that DEB cross-links deoxyguanosine residues within 5'-GNC sequences in synthetic DNA, in restriction fragments, and in defined sequence nucleosomes. The current study utilized the polymerase chain reaction (PCR) to examine DEB damage frequencies within nuclear genes, found within "open" regions of chromatin, as compared to regions of unexpressed sequence that reside in tightly packed, "closed" chromatin, to more closely model DEB reactivity in vivo. These initial studies have been performed in chicken liver homogenates. Preliminarily, we have found a dose-dependent DEB lesion-forming response within "open" chromatin. DEB appears to have little-to-no effect upon regions of "closed" chromatin.
Resumo:
Reuse of wastewater to irrigate food crops is being practiced in many parts of the world and is becoming more commonplace as the competition for, and stresses on, freshwater resources intensify. But there are risks associated with wastewater irrigation, including the possibility of transmission of pathogens causing infectious disease, to both workers in the field and to consumers buying and eating produce irrigated with wastewater. To manage these risks appropriately we need objective and quantitative estimates of them. This is typically achieved through one of two modelling approaches: deterministic or stochastic. Each parameter in a deterministic model is represented by a single value, whereas in stochastic models probability functions are used. Stochastic models are theoretically superior because they account for variability and uncertainty, but they are computationally demanding and not readily accessible to water resource and public health managers. We constructed models to estimate risk of enteric virus infection arising from the consumption of wastewater-irrigated horticultural crops (broccoli, cucumber and lettuce), and compared the resultant levels of risk between the deterministic and stochastic approaches. Several scenarios were tested for each crop, accounting for different concentrations of enteric viruses and different lengths of environmental exposure (i.e. the time between the last irrigation event and harvest, when the viruses are liable to decay or inactivation). In most situations modelled the two approaches yielded similar estimates of risk (within 1 order-of-magnitude). The two methods diverged most markedly, up to around 2 orders-of-magnitude, when there was large uncertainty associated with the estimate of virus concentration and the exposure period was short (1 day). Therefore, in some circumstances deterministic modelling may offer water resource managers a pragmatic alternative to stochastic modelling, but its usefulness as a surrogate will depend upon the level of uncertainty in the model parameters.
Resumo:
Hev b 6.01 is a major allergen of natural rubber latex with sensitization of 70–86% of latex glove-allergic subjects. Recently, we mapped the immunodominant T cell sites of Hev b 6.01 to the highly IgE-reactive hevein (Hev b 6.02) domain. Hev b 6.01 contains 14 cysteine residues with multiple disulphide bridges stabilizing tertiary conformation. With the goal of a standardized specific immunotherapy we developed hypoallergenic Hev b 6.01 mutants by site-directed mutagenesis of selected cysteine residues (3, 12, 17, and 41) within the Hev b 6.02 domain. Peptides corresponding to the Hev b 6.02 domain of two of the mutants were also synthesized. These mutants and peptide variants showed markedly decreased or ablated latex-allergic patient serum IgE binding by immunoblotting and ELISA. Basophil activation testing confirmed markedly decreased activation with successive cysteine substitutions of the mutants and complete abrogation with the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide. Retention of T cell reactivity is crucial for effective specific immunotherapy and all mutants and peptide variants maintained their latex-specific T cell reactivity. The ablated allergenicity but retained T cell reactivity of the Hev b 6.02 (Cys 3, 12, 17, 41 Ala) peptide suggests this peptide is a suitable candidate for inclusion in a latex immunotherapy preparation.
Resumo:
In this paper I consider some issues that I, as a creative writer and academic, find with the concept and current understandings of the term creative industries. The subject of creative industries is not one that has been adequately teased out in relation to creative writing, even though the creative industries model has been a strong force in cultural policymaking internationally since the late 1990s. It influences policies that in turn may affect writers, especially those applying for state or national funds to resource their writing, and also writers working within the academy and attempting to gain recognition and funding for creative work there. The issues relating to creative industries are also particularly pertinent at this time in Australian universities, as the new system of research quality measurement is negotiated, and creative arts scholars, including those in creative writing, struggle to define their work in terms of those negotiations. I will argue that the recent work of Paul Carter looks towards ways in which creative industries may be more inclusive and useful for the creative arts, including creative writing, and suggest that a reclaimed term, creative ecologies, indicates a good way of taking creative industries into the future.
Resumo:
We investigate cross-market trading dynamics in futures contracts written on seemingly unrelated commodities that are consumed by a common industry. On the Tokyo Commodity Exchange, we find such evidence in natural rubber (NR), palladium (PA) and gasoline (GA) futures markets. The automobile industry is responsible for more than 50% of global demand for each of these commodities. VAR estimation reveals short-run cross-market interaction between NR and GA, and from NR to PA. Cross-market influence exerted by PA is felt in longer dynamics, with PA volatility (volume) affecting NR (GA) volume (volatility). Our findings are robust to lag-specification, volatility measure, and consistent with full BEKK-GARCH estimation results. Further analysis, which benchmarks against silver futures market, TOCOM index and TOPIX transportation index, confirms that our results are driven by a common industry exposure, and not a commodity market factor. A simple trading rule that incorporates short-run GA and long-run PA dynamics to predict NR return yields positive economic profit. Our study offers new insights into how commodity and equity markets relate at an industry level, and implications for multi-commodity hedging.
Resumo:
We propose and document robust evidence of cross-market return, volatility, and volume interactions among futures contracts written seemingly unrelated commodities exposed to a common industry. On the Tokyo Commodity Exchange, we find such evidence in natural rubber (NR), aluminum (AL) and gasoline (GA) futures markets, which are complementary commodities heavily consumed by Japan's automobile industry. Our VAR results indicate that (i) for shorter dynamics, NR and GA volatility both influence AL volatility; GA volume affects NR volatility and volume; the GA market is immune to both NR and AL trading activities; (ii) for longer dynamics, AL volume affects both NR volume and GA volatility; NR volume influences GA volume. These results are robust to lag-specifications, volatility measures and are consistent with full BEKK-GARCH estimates. Further analysis using the silver contract, TOCOM and TOPIX transportation indices, shows that a commodity market factor cannot explain our result. Our results offer insights into how commodity and equity markets relate at an industry level.
Resumo:
The emergence of Indochina in the French imagination was articulated in both representational and institutional modes. Representation involves the transmission of colonial ideals through more obtuse means; that is, through literary texts, travelogues, exhibitions, film and advertising. However, these textual sites feed from and invest in a material situation, which was the institutional arm of colonialism. Indochina was institutionally articulated in cartographic maps and surveys, in the new social spaces of cities and towns, in architectural and technological forms, through social technologies of discipline and welfare and in cultural and religious organisations. The aim of this thesis is to analyse, across a number of textual sites, the representation and institutionalisation of Otherness through the politics of space in the French colony of Indochina, Indochine in this sense becomes a spatial discourse. The French constructed a mental and physical space for Indochina by blanketing and suffocating the original cultural landscape, which in fact had to be ignored for this process to occur. What actually became manifest as a result of this projection stemmed from the French imagination. Just as the French manipulated space, language also underwent the same process of reduction. The Vietnamese script was latinised to make it more 'useable' and ‘accessible’. Through christening the union of Indochina; initiating a comprehensive writing reform; and renaming the streets in the colonial cities, the French used language us another tool for 'making transparent'. Furthermore, the colonial powers established a communication and transport network throughout the colony in an attempt to materialise their fictive (artificial) vision of a unified French Indochinese space. The accessibility and design of these different modes of transport reflected the gendered, racial and class divisions inherent in the colonial establishment. At the heart of representing and institutionalising Indochina was the desire to control and contain. This characterised French imperial ordering of space in the city and the rural areas. In rural areas land was divided into small parcels and alienated to individuals or worked into precise grids for the rubber plantation. In urban centres the native quarter was clearly demarcated from the European quarter which functioned as its modern, progressive Other. The rationale behind this segregation was premised on European, nineteenth century discourses of race, class, gender and hygiene. Influenced by Darwinian and neo-Lamarkian theories of race, this biological discourse identified the 'working class', 'women' and 'the native' as not only biologically but also culturally inferior. They were perceived as a potential, degenerative threat to the biological, cultural and industrial development of the nation. In the colonial context, space was thus ordered and domesticated to control the native population. Coextensively, the literature which springs from such a structure will be tainted by the same ideas, and thus the spaces it formulates within the readers mind feed on and reinforce this foundation. Examples of gender and indigenous narratives which contest this imaginative, transparent topography are analysed throughout this thesis. They provide instances of struggle and resistance which undermine the ideal/stereotypical level of architectural and planned space and delineate an alternative insight into colonial spatial and social relations. The fictional accounts of European women and indigenous writers both challenge and reaffirm the fixity of some of these idealised colonial boundaries. In various literary, historical, political, architectural and cinematic discourses Indochina has been und continues to be depicted as a modern city and exotic Utopia. Informed by the mood of nostalgia, exotic images of Indochina have resurfaced in contemporary French culture. France's continued desire to create, control and maintain an Indochinese space in the French public imagination reinforces the multi-layered, interconnected and persistent nature of colonial discourse.
Resumo:
Advanced polymeric materials and their respective composites are fast becoming one of the world's most frequently used engineering materials. They find application in the manufacture of e.g. boat hulls, high performance motor vehicles, aircraft components and sports goods. Their high specific strength and specific stiffness give them the edge in applications where weight savings are critical, but their long-term durability is often questioned. These materials are susceptible to environmental conditions such as temperature and humidity. There is also a lack of relevant data, due to the long time-scales required for testing. In this study, the Raman technique has been used to monitor the degradation of two composite systems, namely: a rubber toughened vinylester material used in the marine industry and a high temperature bismaleimide/carbon fibre aerospace composite. Preliminary Raman studies show that the toughening rubber particles dispersed in the cured vinylester resin are leached out during hygrothermal ageing. The weight gain during ageing suggests that this leaching process occurs concurrently with the absorption of water molecules. An increase in the degree of cross-linking is observed when bismaleimide/carbon fibre composite is aged at high temperature. This cross- linking tendency decreases with increasing depth within the carbon fibre bundle.
Resumo:
This research project aimed to develop an understanding of the structure-property relationships of nanocomposite materials (injection moulded and fibres) based on nylon 6, MXD6 and their blends, with a layered silicate in combination with polyhedral oligomeric silsesquioxane nanoparticles and SEBS rubber particles.
Resumo:
This paper reports on the second phase of a research project aimed at the development of an environmentally friendly noise barrier for urban freeways, also known as KMAK (Krezel and McManus, 2007). The concrete barrier, which has some unique capabilities to mitigate transportation noise, is made from recycled concrete (RC) aggregate and industrial by-products such as fly ash and reclaimed water. The current developmental work expands on a research project that resulted in a two-layer (2L) concrete barrier. Two prototypes of the 2L barrier were produced, followed by extensive acoustic testing and a number of simulations where standard timber and/or concrete barriers were substituted with KMAK barrier (Krezel et al, 2004). Current research investigates a variety of architectural finishes applied to the original KMAK barrier with the aim of improving its visual appearance and also fine-tuning its acoustic performance. The new three-layer (3L) barrier optimises sound absorption in a frequency range characteristic to that of transportation noise, especially road traffic noise. Three major aspects related to the development of architectural finishes were considered; environmentally responsible materials, surface features and production methods. The light-weight material used in the architectural finish is based on ordinary Portland cement (OPC) and uses very fine fraction of RC aggregate. The manufacturing process of the 3L barrier was tested in a commercial setting and two sets of prototype barrier were cast. An innovative, cost effective method of applying pattern and perforation to the surface of architectural finish was also developed and tested. The findings of the current investigation demonstrate that there is a positive correlation between surface features, percentage of perforation as well as depth of the architectural layer and increased potential of the 3L barrier to mitigate transportation noise. On average, the addition of perforated architectural finish contributes to 20% increase in sound absorption. The preliminary results also show that the sound absorbency of the 3L barrier can be better controlled and tuned to specific noise frequency. The visual appearance has been significantly improved with the addition of the architectural finish, which makes the barrier an attractive, feasible and viable alternative to road barriers made from standard concrete or timber.
Resumo:
The dielectric properties of conducting polymer composites containing polypyrrole (PPy) crushed films, PPy powder, polyaniline (PAn) base and acid powders as the dispersants and silicone rubber and vinyl ester as matrix materials have been investigated in the frequency range 2-18 GHz. The dielectric parameters such as the real part, epsiprime, and imaginary part, epsiPrime, of the permittivity and loss tangent, tandelta, increase with increasing conductivity and concentration of the dispersant. The geometrical shape of the dispersant governs the ability of conductive network formation which is indicated by a large drop in the resistivity of the composite. Also, dispersant/matrix interactions and physical properties of the matrix influence the agglomeration of the dispersant phase which, in turn, affects the dielectric properties of the composites. Flakes of PPy obtained by crushing highly conductive films and large PAn powder aggregates were unable to form a conducting network. The composites without a network of dispersant exhibit low dielectric parameters. On the other hand, high values of tan delta ranging from 0.7–1.1 were achieved for the PPy powder (15 parts)/silicone rubber composites where a conducting network was observed.
Resumo:
Gasoline (GA) and kerosene (KO) are extracted from crude oil (CO), such that the three fuel commodities share a chemical link. On the other hand, GA also shares an industrial link with natural rubber (NR) and palladium (PA) as complementary commodities that are heavily consumed by the automobile industry. We contrast the information content embedded in the two economic linkages. Focusing on TOCOM futures contracts written on the five commodities and centering on GA, we confirm that incremental information provided by either CO, KO or NR, PA over a buy-and-hold strategy and a naive forecast, are both statistically and economically significant. While the chemical link forecast is more profitable, a double-link forecast generated from a VECM with two cointegrating vectors (KO-GA and GANR prices) outperforms both single-link forecasts based on risk-adjusted profit net of transaction costs. Further comparisons against the profitability of commodity-based momentum strategies documented in Erb and Harvey (2006) and Miffre and Rallis (2007) show that the double-link forecast holds its own against the most profitable of the 75 momentum strategies considered. This strongly suggests that not only are there incremental profits to be gained from harnessing and combining economic links among commodity futures, the resultant incremental profits are economically significant against other proven commodity-based trading strategies in the existing literature.
Resumo:
This paper reports on the second phase of a research project aimed at the development of an environmentally friendly noise barrier for urban freeways, also known as KMAK [1]. The concrete barrier, which has some unique capabilities to mitigate transportation noise, is made from recycled concrete (RC) aggregate and industrial by-products such as fly ash and reclaimed water. The current developmental work expands on a research project that resulted in a two-layer (2L) concrete barrier. Two prototypes of the 2L barrier were produced, followed by extensive acoustic testing and a number of simulations where standard timber and/or concrete barriers were substituted with KMAK barrier [2]. Current research investigates a variety of architectural finishes applied to the original KMAK barrier with the aim of improving its visual appearance and also fine-tuning its acoustic performance. The new three-layer (3L) barrier optimizes sound absorption in a frequency range characteristic similar to that of transportation noise, especially road traffic noise. Three major aspects related to the development of architectural finishes were considered; environmentally responsible materials, surface features, and production methods. The findings of the current investigation demonstrate that there is a positive correlation between surface features, percentage of perforation as well as depth of the architectural layer, and increased potential of the 3L barrier to mitigate transportation noise. On average, the addition of perforated architectural finish contributes to a 20% increase in sound absorption. The preliminary results also show that the sound absorbency of the 3L barrier can be better controlled and tuned to specific noise frequency than the 2L type. The visual appearance has been significantly improved with the addition of the architectural finish, which makes the barrier an attractive, feasible, and viable alternative to road barriers made from standard concrete or timber.