941 resultados para Waste materials as coarse aggregate
Resumo:
A system requiring a waste management license from an enforcement agency has been introduced in many countries. A license system is usually coupled with fines, a manifest, and a disposal tax. However, these policy devices have not been integrated into an optimal policy. In this paper we derive an optimal waste management policy by using those policy devices. Waste management policies are met with three difficult problems: asymmetric information, the heterogeneity of waste management firms, and non-compliance by waste management firms and waste disposers. The optimal policy in this paper overcomes all three problems.
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It is well known that China and India have been recycling centers of WEEE, especially printed circuit boards, and that serious environmental pollution in these countries has been generated by improper recycling methods. After the governments of China and India banned improper recycling by the informal sector, improper recycling activities spread to other places. Then, these governments changed their policies to one of promoting proper recycling by introducing a scheme, under which E-waste recycling requires a license issued by the government. In this paper, the effectiveness of that license scheme is examined by means of an economic model. It can be shown that the license scheme can work effectively only if disposers of E-waste have a responsibility to sell E-waste to license holders. Our results run counter to the idea that international E-waste trade should be banned and provide an alternative solution to the problem.
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The construction industry is one of the largest sources of carbon emissions. Manufacturing of raw materials, such as cement, steel and aluminium, is energy intensive and has considerable impact on carbon emissions level. Due to the rising recognition of global climate change, the industry is under pressure to reduce carbon emissions. Carbon labelling schemes are therefore developed as meaningful yardsticks to measure and compare carbon emissions. Carbon labelling schemes can help switch consumer-purchasing habits to low-carbon alternatives. However, such switch is dependent on a transparent scheme. The principle of transparency is highlighted in all international greenhouse gas (GHG) standards, including the newly published ISO 14067: Carbon footprint of products – requirements and guidelines for quantification and communication. However, there are few studies which systematically investigate the transparency requirements in carbon labelling schemes. A comparison of five established carbon labelling schemes, namely the Singapore Green Labelling Scheme, the CarbonFree (the U.S.), the CO2 Measured Label and the Reducing CO2 Label (UK), the CarbonCounted (Canada), and the Hong Kong Carbon Labelling Scheme is therefore conducted to identify and investigate the transparency requirements. The results suggest that the design of current carbon labels have transparency issues relating but not limited to the use of a single sign to represent the comprehensiveness of the carbon footprint. These transparency issues are partially caused by the flexibility given to select system boundary in the life cycle assessment (LCA) methodology to measure GHG emissions. The primary contribution of this study to the construction industry is to reveal the transparency requirements from international GHG standards and carbon labels for construction products. The findings also offer five key strategies as practical implications for the global community to improve the performance of current carbon labelling schemes on transparency.
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Annually, several million tonnes of waste are produced from reworks, demolition, and use of substandard materials. Building Information Modelling (BIM), a digital representation of facilities and their constituent data, is a viable means of addressing some concerns about the impacts of these processes. BIM functionalities can be extended and combined with rich building information from specifications and product libraries, for efficient, streamlined design and construction. This paper conceptualises a framework for BIM-knowledge transfer from advanced economies for adaptation and use in urban development works in developing nations using the Sydney Down Under and Lagos Eko Atlantic projects as reference points. We present a scenario that highlights BIM-based lifecycle planning/specifications as agents of sustainable construction (in terms of cost and time) crucial to the quality of as-built data from early on in city development. We show how, through the use of BIM, city planners in developing nations can avoid high, retrospective (and sometimes wasteful) maintenance costs and leapfrog infrastructure management standards of advanced economies. Finally, this paper illustrates how BIM can address concerns about economic sustainability during city development in developing countries by enriching model objects with specification information sourced from a product library.
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Plant food materials have a very high demand in the consumer market and therefore, improved food products and efficient processing techniques are concurrently being researched in food engineering. In this context, numerical modelling and simulation techniques have a very high potential to reveal fundamentals of the underlying mechanisms involved. However, numerical modelling of plant food materials during drying becomes quite challenging, mainly due to the complexity of the multiphase microstructure of the material, which undergoes excessive deformations during drying. In this regard, conventional grid-based modelling techniques have limited applicability due to their inflexible grid-based fundamental limitations. As a result, meshfree methods have recently been developed which offer a more adaptable approach to problem domains of this nature, due to their fundamental grid-free advantages. In this work, a recently developed meshfree based two-dimensional plant tissue model is used for a comparative study of microscale morphological changes of several food materials during drying. The model involves Smoothed Particle Hydrodynamics (SPH) and Discrete Element Method (DEM) to represent fluid and solid phases of the cellular structure. Simulation are conducted on apple, potato, carrot and grape tissues and the results are qualitatively and quantitatively compared and related with experimental findings obtained from the literature. The study revealed that cellular deformations are highly sensitive to cell dimensions, cell wall physical and mechanical properties, middle lamella properties and turgor pressure. In particular, the meshfree model is well capable of simulating critically dried tissues at lower moisture content and turgor pressure, which lead to cell wall wrinkling. The findings further highlighted the potential applicability of the meshfree approach to model large deformations of the plant tissue microstructure during drying, providing a distinct advantage over the state of the art grid-based approaches.
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This thesis developed a high preforming alternative numerical technique to investigate microscale morphological changes of plant food materials during drying. The technique is based on a novel meshfree method, and is more capable of modeling large deformations of multiphase problem domains, when compared with conventional grid-based numerical modeling techniques. The developed cellular model can effectively replicate dried tissue morphological changes such as shrinkage and cell wall wrinkling, as influenced by moisture reduction and turgor loss.
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(Equation Presented). A series of star-shaped organic semiconductors have been synthesized from 1,3,6,8-tetrabromopyrene. The materials are soluble in common organic solvents allowing for solution processing of devices such as light-emitting diodes (OLEDs). One of the materials, 1,3,6,8-tetrakis(4- butoxyphenyl)pyrene, has been used as the active emitting layer in simple solution-processed OLEDs with deep blue emission (CIE = 0.15, 0.18) and maximum efficiencies and brightness levels of 2.56 cd/A and >5000 cd/m2, respectively.
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Thirty workers who had been exposed to combustion products for several years due to testing of flame retarding qualities of building materials and 30 controls from the same facility were investigated. Concentrations found in samples taken from different places of the facility were up to 14,660 μg/kg for polybrominated dibenzofurans and up to 67.1 μg/kg for polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). Physical examination, routine laboratory parameters, and blood fat concentrations of PCDDs and PCDFs revealed normal findings. Neurotoxic symptoms showed a weak tendency of overrepresentation among the exposed workers. The frequency of neurobehavioural symptoms increased significantly with trait anxiety independent of exposure to combustion products. (C) 2000 Elsevier Science Ltd.
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Domestic food wastage is a growing problem for the environment and food security. Some causes of domestic food wastes are attributed to a consumer’s behaviours during food purchasing, storage and consumption, such as: excessive food purchases and stockpiling in storage. Recent efforts in human-computer interaction research have examined ways of influencing consumer behaviour. The outcomes have led to a number of interventions that assist users with performing everyday tasks. The Internet Fridge is an example of such an intervention. However, new pioneering technologies frequently confront barriers that restrict their future impact in the market place, which has prompted investigations into the effectiveness of behaviour changing interventions used to encourage more sustainable practices. In this paper, we investigate and compare the effectiveness of two interventions that encourage behaviour change: FridgeCam and the Colour Code Project. We use FridgeCam to examine how improving a consumer’s food supply knowledge can reduce food stockpiling. We use the Colour Code Project to examine how improving consumer awareness of food location can encourage consumption of forgotten foods. We explore opportunities to integrate these interventions into commercially available technologies, such as the Internet Fridge, to: (i) increase the technology’s benefit and value to users, and (ii) promote reduced domestic food wastage. We conclude that interventions improving consumer food supply and location knowledge can promote behaviours that reduce domestic food waste over a longer term. The implications of this research present new opportunities for existing and future technologies to play a key role in reducing domestic food waste.
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A series of large-scale photographic collages and videoworks installed in the 2010 The Beauty Of Distance: Songs of Survival in a Precarious Age, Sydney Biennale Cockatoo Island, Sydney (cat.)The work addresses her ongoing interest in feminist strategies for negotiating individual and collective identities, equality,and social activism.
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This paper translates the concepts of sustainable production to three dimensions of economic, environmental and ecological sustainability to analyze optimal production scales by solving optimizing problems. Economic optimization seeks input-output combinations to maximize profits. Environmental optimization searches for input-output combinations that minimize the polluting effects of materials balance on the surrounding environment. Ecological optimization looks for input-output combinations that minimize the cumulative destruction of the entire ecosystem. Using an aggregate space, the framework illustrates that these optimal scales are often not identical because markets fail to account for all negative externalities. Profit-maximizing firms normally operate at the scales which are larger than optimal scales from the viewpoints of environmental and ecological sustainability; hence policy interventions are favoured. The framework offers a useful tool for efficiency studies and policy implication analysis. The paper provides an empirical investigation using a data set of rice farms in South Korea.
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This article integrates the material/energy flow analysis into a production frontier framework to quantify resource efficiency (RE). The emergy content of natural resources instead of their mass content is used to construct aggregate inputs. Using the production frontier approach, aggregate inputs will be optimised relative to given output quantities to derive RE measures. This framework is superior to existing RE indicators currently used in the literature. Using the exergy/emergy content in constructing aggregate material or energy flows overcomes a criticism that mass content cannot be used to capture different quality of differing types of resources. Derived RE measures are both ‘qualitative’ and ‘quantitative’, whereas existing RE indicators are only qualitative. An empirical examination into the RE of 116 economies was undertaken to illustrate the practical applicability of the new framework. The results showed that economies, on average, could reduce the consumption of resources by more than 30% without any reduction in per capita gross domestic product (GDP). This calculation occurred after adjustments for differences in the purchasing power of national currencies. The existence of high variations in RE across economies was found to be positively correlated with participation of people in labour force, population density, urbanisation, and GDP growth over the past five years. The results also showed that economies of a higher income group achieved higher RE, and those economies that are more dependent on imports and primary industries would have lower RE performance.
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Current practice based research explores the organic properties of edible materials such as rice-paper to contemplate possible material usage from garment manufacture, landscape interventions and temporary architectural canopies/facades. Research outcomes have been published through The International Conference on Designing Food and Designing for Food, London 2012, and in Burke, Anthony + Reinmuth, Gerard (Eds.) (2012) 'Formations: New Practices in Australian Architecture.' Australian Pavilion 13th International Architecture Exhibition la biennale di Venezia.