905 resultados para non-metallic material
Resumo:
High density development has been seen as a contribution to sustainable development. However, a number of engineering issues play a crucial role in the sustainable construction of high rise buildings. Non linear deformation of concrete has an adverse impact on high-rise buildings with complex geometries, due to differential axial shortening. These adverse effects are caused by time dependent behaviour resulting in volume change known as ‘shrinkage’, ‘creep’ and ‘elastic’ deformation. These three phenomena govern the behaviour and performance of all concrete elements, during and after construction. Reinforcement content, variable concrete modulus, volume to surface area ratio of the elements, environmental conditions, and construction quality and sequence influence on the performance of concrete elements and differential axial shortening will occur in all structural systems. Its detrimental effects escalate with increasing height and non vertical load paths resulting from geometric complexity. The magnitude of these effects has a significant impact on building envelopes, building services, secondary systems, and lifetime serviceability and performance. Analytical and test procedures available to quantify the magnitude of these effects are limited to a very few parameters and are not adequately rigorous to capture the complexity of true time dependent material response. With this in mind, a research project has been undertaken to develop an accurate numerical procedure to quantify the differential axial shortening of structural elements. The procedure has been successfully applied to quantify the differential axial shortening of a high rise building, and the important capabilities available in the procedure have been discussed. A new practical concept, based on the variation of vibration characteristic of structure during and after construction and used to quantify the axial shortening and assess the performance of structure, is presented.
Resumo:
Alginate microspheres are considered a promising material as a drug carrier in bone repair due to excellent biocompatibility, but their main disadvantage is low drug entrapment efficiency and non-controllable release. The aim of this study was to investigate the effect of incorporating mesoporous bioglass (MBG), non-mesoporous bioglass (BG) or hydroxyapatite (HAp) into alginate microspheres on their drug-loading and release properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and atomic emission spectroscopy (AES) were used to analyse the composition, structure and dissolution of bioactive inorganic materials and their microspheres. Dexamethasone (DEX)-loading and release ability of four microspheres were tested in phosphate buffered saline with varying pHs. Results showed that the drug-loading capacity was enhanced with the incorporation of bioactive inorganic materials into alginate microspheres. The MBG/Alginate microspheres had the highest drug loading ability. DEX release from alginate microspheres correlated to the dissolution of MBG, BG and HAp in PBS, and that the pH was an efficient factor in controlling the DEX release; a high pH resulted in greater DEX release, whereas a low pH delayed DEX release. In addition, MBG/alginate, BG/alginate and HAp/alginate microspheres had varying apatite-formation and dissolution abilities, which indicate that the composites would behave differently with respect to bioactivity. The study suggests that microspheres made of a composite of bioactive inorganic materials and alginate have a bioactivity and degradation profile which greatly improves their drug delivery capacity, thus enhancing their potential applications as bioactive filler materials for bone tissue regeneration.
Resumo:
How do non-Indigenous theatre practitioners, especially actors, access and incorporate Aboriginal themes in the plays they create or perform in? Will it ever be acceptable for a non-Aboriginal actor to play an Aboriginal role? In literature there are clear protocols for writing Aboriginal characters and themes. In the visual arts and in dance, non-Indigenous practitioners might 'reference' Aboriginal themes, but what about in theatre performance? This research embodies one cultural dilemma in a creative project and exegesis: exploring the complex issues which emerge when an Aboriginal playwright is commissioned to write an 'Aboriginal themed' play for two non-Aboriginal actors.
Resumo:
This article is an abbreviated version of a debate between two economists holding somewhat different perspectives on the nature of non-market production in the space of new digital media. While the ostensible focus here is on the role of markets in the innovation of new technologies to create new economic value, this context also serves to highlight the private and public value of digital literacy.
Resumo:
This research explores the empirical association between takeover bid premium and acquired (purchased) goodwill, and tests whether the strength of the association changes after the passage of approved accounting standard AASB 1013 in Australia in 1988. AASB 1013 mandated capitalization and amortization of acquired goodwill to the income statement over a maximum period of 20 years. We use regressions to assess how the association between bid premium and acquired goodwill varies in the pre-AASB and post-AASB 1013 periods after controlling for confounding factors. Our results show that reducing the variety of accounting policy options available to bidder management after an acquisition results in a systematic reduction in the strength of the association between premium and goodwill.
Resumo:
Discusses the role of legislation and codes of conduct in influencing the behaviour of non-executive directors. Outlines the functions of a board of directors and considers the role on non-executive directors in particular. Traces the development of standards of skill required on non-executive directors both under the Australian Corporations Act 2001 and under common law. Questions whether these have brought about a real change in behaviour. Considers whether professionalisation of directorship could be more effective.
Resumo:
Over recent decades there has been growing interest in the role of non-motorized modes in the overall transport system (especially walking and cycling for private purposes) and many government initiatives have been taken to encourage these active modes. However there has been relatively little research attention given to the paid form of non-motorized travel which can be called non-motorized public transport (NMPT). This involves cycle-powered vehicles which can carry several passengers (plus the driver) and a small amount of goods; and which provide flexible hail-and-ride services. Effectively they are non-motorized taxis. Common forms include cycle-rickshaw (Bangladesh, India), becak (Indonesia), cyclos (Vietnam, Cambodia), bicitaxi (Columbia, Cuba), velo-taxi (Germany, Netherland), and pedicabs (UK, Japan, USA). --------- The popularity of NMPT is widespread in developing countries, where it caters for a wide range of mobility needs. For instance in Dhaka, Bangladesh, rickshaws are the preferred mode for non-walk trips and have a higher mode share than cars or buses. Factors that underlie the continued existence and popularity of NMPT in many developing countries include positive contribution to social equity, micro-macro economic significance, employment creation, and suitability for narrow and crowded streets. Although top speeds are lower than motorized modes, NMPT is competitive and cost-effective for short distance door-to-door trips that make up the bulk of travel in many developing cities. In addition, NMPT is often the preferred mode for vulnerable groups such as females, children and elderly people. NMPT is more prominent in developing countries but its popularity and significance is also gradually increasing in several developed countries of Asia, Europe and parts of North America, where there is a trend for the NMPT usage pattern to broaden from tourism to public transport. This shift is due to a number of factors including the eco-sustainable nature of NMPT; its operating flexibility (such as in areas where motorized vehicle access is restricted or discouraged through pricing); and the dynamics that it adds to the urban fabric. Whereas NMPT may have been seen as a “dying” mode, in many cities it is maintaining or increasing its significance and with potential for further growth. --------- This paper will examine and analyze global trends in NMPT incorporating both developing and developed country contexts and issues such as usage patterns; NMPT policy and management practices; technological development; and operational integration of NMPT into the overall transport system. It will look at how NMPT policies, practices and usage have changed over time and the differing trends in developing and developed countries. In particular, it will use Dhaka, Bangladesh as a case study in recognition of its standing as the major NMPT city in the world. The aim is to highlight NMPT issues and trends and their significance for shaping future policy towards NMPT in developing and developed countries. The paper will be of interest to transport planners, traffic engineers, urban and regional planners, environmentalists, economists and policy makers.
Resumo:
This approach to sustainable design explores the possibility of creating an architectural design process which can iteratively produce optimised and sustainable design solutions. Driven by an evolution process based on genetic algorithms, the system allows the designer to “design the building design generator” rather than to “designs the building”. The design concept is abstracted into a digital design schema, which allows transfer of the human creative vision into the rational language of a computer. The schema is then elaborated into the use of genetic algorithms to evolve innovative, performative and sustainable design solutions. The prioritisation of the project’s constraints and the subsequent design solutions synthesised during design generation are expected to resolve most of the major conflicts in the evaluation and optimisation phases. Mosques are used as the example building typology to ground the research activity. The spatial organisations of various mosque typologies are graphically represented by adjacency constraints between spaces. Each configuration is represented by a planar graph which is then translated into a non-orthogonal dual graph and fed into the genetic algorithm system with fixed constraints and expected performance criteria set to govern evolution. The resultant Hierarchical Evolutionary Algorithmic Design System is developed by linking the evaluation process with environmental assessment tools to rank the candidate designs. The proposed system generates the concept, the seed, and the schema, and has environmental performance as one of the main criteria in driving optimisation.
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It has been suggested that although the most theorisation about globalisation has emerged from “western” contexts, the material implications of globalisation have been felt most strongly in non-western regions. With this in mind, we are undertaking a situated analysis of how two states, Singapore and Hong Kong, are interacting with the broader processes of globalisation through their educational policies. We apply Foucault's conceptual tool of governmentality to understand (i) the conduct of governing in the contemporary nation-state, and (ii) how the “right” rationalities are being inculcated by government to create “desiring subjects” who will play their part in ensuring national prosperity. We use the Asian Economic Crisis as a point of departure to show how global-local tensions are being managed by Singapore and Hong Kong. We conclude that both these global cities have adroitly managed the Asian economic crisis to steer their citizens away from pursuits of greater political freedom and towards concerns of material well being. They have done so through a selective interpretation of globalisation, by simultaneously resisting and embracing the contradictory strands of globalisation. Education has emerged as a critical space for this selective absorption of globalising trends.
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In their statistical analyses of higher court sentencing in South Australia, Jeffries and Bond (2009) found evidence that Indigenous offenders were treated more leniently than non-Indigenous offenders, when they appeared before the court under similar numerical circumstances. Using a sample of narratives for criminal defendants convicted in South Australia’s higher courts, the current article extends Jeffries and Bond’s (2009) prior statistical work by drawing on the ‘focal concerns’ approach to establish whether, and in what ways, Indigeneity comes to exert a mitigating influence over sentencing. Results show that the sentencing stories of Indigenous and non-Indigenous offenders differed in ways that may have reduced assessments of blameworthiness and risk for Indigenous defendants. In addition, judges highlighted a number of Indigenous-specific constraints that potentially could result in imprisonment being construed as an overly harsh and costly sentence for Indigenous offenders.
Resumo:
The measurement of broadband ultrasonic attenuation (BUA) in cancellous bone at the calcaneus for the assessment of osteoporosis was first described within this journal 25 years ago. It was recognized in 2006 by Universities UK as being one of the ‘100 discoveries and developments in UK Universities that have changed the world’ over the past 50 years. In 2008, the UK's Department of Health also recognized BUA assessment of osteoporosis in a publication highlighting 11 projects that have contributed to ‘60 years of NHS research benefiting patients’. The BUA technique has been extensively clinically validated and is utilized worldwide, with at least seven commercial systems currently providing calcaneal BUA measurement. However, there is still no fundamental understanding of the dependence of BUA upon the material and structural properties of cancellous bone. This review aims to provide an ‘engineering in medicine’ perspective and proposes a new paradigm based upon phase cancellation due to variation in propagation transit time across the receive transducer face to explain the non-linear relationship between BUA and bone volume fraction in cancellous bone.
Resumo:
This paper considers the question of designing a fully image based visual servo control for a dynamic system. The work is motivated by the ongoing development of image based visual servo control of small aerial robotic vehicles. The observed targets considered are coloured blobs on a flat surface to which the normal direction is known. The theoretical framework is directly applicable to the case of markings on a horizontal floor or landing field. The image features used are a first order spherical moment for position and an image flow measurement for velocity. A fully non-linear adaptive control design is provided that ensures global stability of the closed-loop system. © 2005 IEEE.
Resumo:
Non-motorized public transport (NMPT) involves cycle-powered vehicles that carry several passengers and a small amount of goods; and provide flexible hail-and-ride services. Effectively they are non-motorized taxis. NMPT is widespread in developing countries, where it caters for a wide range of mobility needs. Common forms include cycle-rickshaw (Bangladesh, India), becak (Indonesia), cyclos (Vietnam, Cambodia), bicitaxi (Columbia, Cuba). Over the last 10-15 years there has also been a re-emergence of NMPT in the form of pedicabs in many developed countries because of the operating flexibility of NMPT, its eco-sustainability, and its ability to operate where use of motorized vehicles is restricted. In particular, in cities such as Berlin, London, New York and Vancouver, pedicabs are making the transition from ‘novelty’ to ‘serious’ transport mode. This is creating new transport policy/planning questions about pedicab operation and integration. This paper examines the phenomenon of NMPT and where it is heading. It uses case studies from Asia/Latin America and Europe/North America to examine emerging NMPT issues and possible responses, and how this may affect NMPT in Australia and New Zealand where it is still somewhat a ‘novelty’ but has potential as both an opportunity and a challenge.
Resumo:
Recent Australian research on Indigenous sentencing primarily explores whether disparities in sentencing outcomes exist. Little is known about how judges perceive or refer to Indigenous defendants and their histories, and how they interpret the circumstances of Indigenous defendants in justifying their sentencing decisions. Drawing on the ‘focal concerns’ approach, this study presents a narrative analysis of a sample of judges’ sentencing remarks for Indigenous and non-Indigenous criminal defendants convicted in South Australia’s Higher Courts. The analysis found that the sentencing stories of Indigenous and non-Indigenous offenders differed in ways that possibly reduced assessments of blameworthiness and risk for Indigenous defendants.