980 resultados para Concrete and masonry structures


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The G20 forum has acted to crystallise important changes in the architecture of global governance emerging since the 1970s. This has seen the locus of power shift away from the United Nations (UN) System as smaller and poorer states become increasingly adept at exercising their power within UN structures. Yet it is too simple to set the G20 against the UN, for example as minilateralism versus multilateralism. While the UN seems increasingly constrained and less relevant, it is not about to disappear. Moreover, we argue there are two significant obstacles to the G20 claiming the mantle of dominant global governance institution. First, that minilateralism is still a form of multilateralism, and ultimately subject to the same problems with the generation of consensus if extended, as in the G20, to include sufficiently diverse state members for a claim of legitimacy. Second, its emergence from the Global Financial Crisis and historical focus on financial governance means its agenda is excessively narrow at a time when food and environmental crises command similar global political significance. We conclude by considering some of the different elements of the emerging G20/UN dynamic, and whether this emerging dialectic can enhance prospects for wide ranging reforms to global trade, finance and economic structures that are currently incapable of functioning sustainably or preventing wide scale famine.

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Here we report a facile method for controlling the morphology and porosity of porous siloxane membranes through manipulation of the water content of precursor microemulsions. The polymerizable microemulsion precursors consisted of a methacrylate-terminated siloxane macromonomer (MTSM) as the oil phase, nonionic surfactant (Teric G9A8), water, and cosurfactant (isopropanol). Photo-polymerization of the oil phase in the parent microemulsion solutions resulted in polymeric solids, and subsequent removal of the extractable components yielded porous PDMS membranes. The pre-cured parent microemulsion solutions and post-cured polymers were characterized by small angle X-ray scattering (SAXS) while the nanostructures of extracted porous polymer membranes were characterized by SAXS, scanning electron microscopy (SEM) and mercury porosimetry. The results indicated that nano- and micro-structures of the membranes could be modulated by the water content of the precursor microemulsions. Further, in situ photo-rheometry was used to follow the microemulsion polymerization process. The rate of polymerization and the mechanical properties of the resulting PDMS membranes also depend on the water content of precursor microemulsions. This study demonstrates a simple approach to the fabrication of a variety of novel porous PDMS membranes with controllable morphology and porosity.

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Identity is complex and it is difficult to come to terms with one’s identity when challenged by cross-cultural and migration transitions and the pressures of globalisation. From such perspectives, I define the terms ‘identity’, and ‘representation’ and how I situate the ‘self’ within such transitions and experiences. Discourses from cultural theorists such as: Zygmunt Bauman, Edward Said, Stuart Hall, Homi Bhabha, Arjun Appadurai and Edward Soja frame notions that support my arguments. My narratives and artworks make reference to my historical legacies, cultural and Diasporic inheritances, sense of belonging from home country and migration transitions. This journey underscores subjectivities in constructing my identities. I describe my own experiences and process of migration transitions to happen within a ‘liminal space,’ as I negotiate and adapt to new social and cultural structures. Through my discussion, I describe how it becomes important to “know who you are” and how to define new ‘spaces’ and parameters of identification and representation. The shifts in ‘spaces’, places’ and new social interaction, I argue indicates hybridity and ambivalences in situating the ‘self’. My arguments extend to reflect on how identity matters, and why it is significant to make it seem present and less as ‘dilemma’ or ‘myth’ in an increasingly diverse, changing and challenging global context.

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Purpose: Studies into ripple effects have previously focused on the interconnections between house price movements across cities over space and time. These interconnections were widely investigated in previous research using vector autoregression models. However, the effects generated from spatial information could not be captured by conventional vector autoregression models. This research aimed to incorporate spatial lags into a vector autoregression model to illustrate spatial-temporal interconnections between house price movements across the Australian capital cities. Design/methodology/approach: Geographic and demographic correlations were captured by assessing geographic distances and demographic structures between each pair of cities, respectively. Development scales of the housing market were also used to adjust spatial weights. Impulse response functions based on the estimated SpVAR model were further carried out to illustrate the ripple effects. Findings: The results confirmed spatial correlations exist in housing price dynamics in the Australian capital cities. The spatial correlations are dependent more on the geographic rather than the demographic information. Originality/value: This research investigated the spatial heterogeneity and autocorrelations of regional house prices within the context of demographic and geographic information. A spatial vector autoregression model was developed based on the demographic and geographic distance. The temporal and spatial effects on house prices in Australian capital cities were then depicted.

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This article examines how meaning is always articulated in the ideological and political structures of society. This becomes apparent when evidencing articulated Aboriginal representation in Australian cinema, which signifies a representation on screen expressive of the ideological and political structures of the historical time periods in which the films were produced. Meaning, which is the relationship between the signifier and its signified, includes both denotation and connotation. Specific connotators can load a sign with multiple meanings leading to a chain of connotations.  The connotations of Aboriginal identity in Australian filmic narratives are influenced by a chain of additional signified, those of: socio-cultural variables and dominant discourses. This article analyses these chains of connotations through an examination of myths and absent signifiers in filmic representations of Aboriginal identity. The films investigated are: Jedda (Charles Chauvel 1955), Walkabout (Nicolas Roeg 1971), Night Cries (Tracey Moffatt 1990) and Rabbit Proof Fence (Philip Noyce 2002).

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Drug targeting is an active area of research and nano-scaled drug delivery systems hold tremendous potential for the treatment of neoplasms. In this study, a novel cyclodextrin (CD)-based nanoparticle drug delivery system has been assembled and characterized for the therapy of folate receptor-positive [FR(+)] cancer. Water-soluble folic acid (FA)-conjugated CD carriers (FACDs) were successfully synthesized and their structures were confirmed by 1D/2D nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and circular dichroism. Drug complexes of adamatane (Ada) and cytotoxic doxorubicin (Dox) with FACD were readily obtained by mixed solvent precipitation. The average size of FACD-Ada-Dox was 1.5-2.5 nm. The host-guest association constant Ka was 1,639 M-1 as determined by induced circular dichroism and the hydrophilicity of the FACDs was greatly enhanced compared to unmodified CD. Cellular uptake and FR binding competitive experiments demonstrated an efficient and preferentially targeted delivery of Dox into FR-positive tumor cells and a sustained drug release profile was seen in vitro. The delivery of Dox into FR(+) cancer cells via endocytosis was observed by confocal microscopy and drug uptake of the targeted nanoparticles was 8-fold greater than that of non-targeted drug complexes. Our docking results suggest that FA, FACD and FACD-Ada-Dox could bind human hedgehog interacting protein that contains a FR domain. Mouse cardiomyocytes as well as fibroblast treated with FACD-Ada-Dox had significantly lower levels of reactive oxygen species, with increased content of glutathione and glutathione peroxidase activity, indicating a reduced potential for Dox-induced cardiotoxicity. These results indicate that the targeted drug complex possesses high drug association and sustained drug release properties with good biocompatibility and physiological stability. The novel FA-conjugated β-CD based drug complex might be promising as an anti-tumor treatment for FR(+) cancer.

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This article discusses the process of writing through devising in performance. It takes as a case study Apart of and A Part From in which muscle and sense memory – touch, smell, taste, sound and sight – were the points of departure for a contemporary performance piece on migration and identity. This was a practice-as-research project aimed to better understand the artist’s body (myself) in improvisation with memory fragments. Working from a non-verbal frame the writing experience began as actions in space, then new memories in my body, to maps on paper, to key word and some staging patterns, to systematic capturing of the textual, rhythmic and spatial structures in the emerging 30-minute performance. Various objects were incorporated to give aesthetic coherence of the piece. The article reports on the processes of writing in action, the writing and performing as lived experience and how the writing emerged from the spaces in between – self and other, self and object, self and space, present self and past self.

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One of the challenges for health reform in Asia is the diverse set of socio-economic and political structures, and the related variability in the direction and pace of health systems and policy reform. This paper aims to make comparative observations and analysis of health policy reform in the context of historical change, and considers the implications of these findings for the practice of health policy analysis. We adopt an ecological model for analysis of policy development, whereby health systems are considered as dynamic social constructs shaped by changing political and social conditions. Utilizing historical, social scientific and health literature, timelines of health and history for five countries (Cambodia, Myanmar, Mongolia, North Korea and Timor Leste) are mapped over a 30-50 year period. The case studies compare and contrast key turning points in political and health policy history, and examines the manner in which these turning points sets the scene for the acting out of longer term health policy formation, particularly with regard to the managerial domains of health policy making. Findings illustrate that the direction of health policy reform is shaped by the character of political reform, with countries in the region being at variable stages of transition from monolithic and centralized administrations, towards more complex management arrangements characterized by a diversity of health providers, constituency interest and financing sources. The pace of reform is driven by a country's institutional capability to withstand and manage transition shocks of post conflict rehabilitation and emergence of liberal economic reforms in an altered governance context. These findings demonstrate that health policy analysis needs to be informed by a deeper understanding and questioning of the historical trajectory and political stance that sets the stage for the acting out of health policy formation, in order that health systems function optimally along their own historical pathways.

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Protein fibre wastes from animal hairs, feathers and insect secreted filaments can be aptly utilized by converting them into ultra-fine particles. Particles from animal protein fibres present large surface-to-weight ratio and significantly enhanced surface reactivity, that have opened up novel applications in both textile and non-textile fields. This review article summarizes the state-of-the-art routes to fabricate ultrafine particles from animal protein fibres, including direct route of mechanical milling of fibres and indirect route from fibre proteins. Ongoing research trends in novel applications of protein fibre particles in various fields, such as biomedical science, environmental protection and composite structures are presented. © 2014 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

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Thousands of the world's offshore oil and gas structures are approaching obsolescence and will require decommissioning within the next decade. Many nations have blanket regulations requiring obsolete structures to be removed, yet this option is unlikely to yield optimal environmental, societal and economic outcomes in all situations. We propose that nations adopt a flexible approach that allows decommissioning options to be selected from the full range of alternatives (including 'rigs-to-reefs' options) on a case-by-case basis. We outline a method of multi-criteria decision analysis (Multi-criteria Approval, MA) for evaluating and comparing alternative decommissioning options across key selection criteria, including environmental, financial, socioeconomic, and health and safety considerations. The MA approach structures the decision problem, forces explicit consideration of trade-offs and directly involves stakeholder groups in the decision process. We identify major decommissioning options and provide a generic list of selection criteria for inclusion in the MA decision process. To deal with knowledge gaps concerning environmental impacts of decommissioning, we suggest that expert opinion feed into the MA approach until sufficient data become available. We conducted a limited trial of the MA decision approach to demonstrate its application to a complex and controversial decommissioning scenario; Platform Grace in southern California. The approach indicated, for this example, that the option 'leave in place intact' would likely provide best environmental outcomes in the event of future decommissioning. In summary, the MA approach will allow the environmental, social, and economic impacts of decommissioning decisions to be assessed simultaneously in a transparent manner. © 2013 Elsevier Ltd.

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This study provides the first assessment of fish associations with oil and gas structures located in deep water (85-175 m) on Australia's north-west continental shelf, using rare oil industry video footage obtained from remotely operated vehicles. A diverse range of taxa were observed associating with the structures, including reef-dependent species and transient pelagic species. Ten commercially fished species were observed, the most abundant of which was Lutjanus argentimaculatus, with an estimated biomass for the two deepest structures (Goodwyn and Echo) of 109 kg.

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A significant feature of contemporary doctoral education is the continuing trend for research and research education to migrate beyond discipline-based institutional teaching and research structures. The result is a more diverse array of settings and arrangements for doctoral education linked to an increasingly global research enterprise. Recognising the complexity of what is a distributed environment challenges some commonly held assumptions about doctoral education and its practice. Drawing on data gathered in an Australian study of PhD programme development in Australia carried out in 2006–2009, the article describes the fluid and complex arrangements forming the ‘experienced environments’ for doctoral candidates, an environment that can afford them varying opportunities and challenges for completing their candidacy. Some implications for doctoral education are discussed.

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This article examines job satisfaction and incentive structures among China's urban workforce. The main determinants of job satisfaction are found to be age, education, occupation and personal income. The criteria that Chinese urban employees considered most important when choosing a job were job stability, a high income and professional development. Employees who considered job stability, high income, professional development opportunities, work/life balance and provision of social insurance as being important when selecting a job were more likely to have higher levels of job satisfaction. © 2008 Elsevier Inc. All rights reserved.

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Purpose – Construction contractors and facility managers are being challenged to minimize the carbon footprint. Life cycle carbon‐equivalent (CO2‐e) accounting, whereby the potential emissions of greenhouse gases due to energy expenditure during construction and subsequent occupation of built infrastructure, generally ceases at the end of the service life. However, following demolition, recycling of demolition waste that becomes incorporated into 2nd generation construction is seldom considered within the management of the carbon footprint. This paper aims to focus on built concrete infrastructure, particularly the ability of recycled concrete to chemically react with airborne CO2, thereby significantly influencing CO2‐e estimates.

Design/methodology/approach – CO2‐e estimates were made in accordance with the methodology outlined in the Australian National Greenhouse Accounts (NGA) Factors and were based on the energy expended for each life cycle activity from audited records. Offsets to the CO2‐e estimates were based on the documented ability of concrete to chemically react with airborne carbon dioxide (“carbonation”) and predictions of CO2 uptake by concrete and recycled concrete was made using existing predictive diffusion models. The author's study focused on a built concrete bridge which was demolished and recycled at the end of the service life, and the recycled concrete was utilized towards 2nd generation construction. The sensitivity of CO2‐e and carbonation estimates were tested on several different types of source demolition waste as well as subsequent construction applications using recycled concrete (RCA). Whole‐of‐life CO2‐e estimates, including carbonation of RCA over the 1st and 2nd generations, were estimated and contrasted with conventional carbon footprints that end at the conclusion of the 1st generation.

Findings – Following demolition, CO2 capture by RCA is significant due to the more permeable nature of the crushed RCA compared with the original built infrastructure. RCA also has considerably greater exposed surface area, relative to volume, than a built concrete structure, and therefore more highly exposed surface to react with CO2: it therefore carbonates more comprehensively. CO2‐e estimates can be offset by as much as 55‐65 per cent when including the contribution of carbonation of RCA built within 2nd generation infrastructure. Further offsets are achievable using blended fly ash or slag cement binders; however, this study has focused on concrete composed of 100 per cent OPC binders and the effects of RCA.

Originality/value – Construction project estimates of life cycle CO2‐e emissions should include 2nd generation applications that follow the demolition of the 1st generation infrastructure. Life cycle estimates generally end at the time of demolition. However, by incorporating the recycled concrete demolition waste into the construction of 2nd generation infrastructure, the estimated CO2‐e is significantly offset during the 2nd generation life cycle by chemical uptake of CO2 (carbonation). This paper provides an approach towards inclusion of 2nd generation construction applications into whole‐of‐life estimates of CO2‐e.

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RNA regulates many biological processes; however, identifying functional RNA sequences and structures is complex and time-consuming. We introduce a method, mutational interference mapping experiment (MIME), to identify, at single-nucleotide resolution, the primary sequence and secondary structures of an RNA molecule that are crucial for its function. MIME is based on random mutagenesis of the RNA target followed by functional selection and next-generation sequencing. Our analytical approach allows the recovery of quantitative binding parameters and permits the identification of base-pairing partners directly from the sequencing data. We used this method to map the binding site of the human immunodeficiency virus-1 (HIV-1) Pr55(Gag) protein on the viral genomic RNA in vitro, and showed that, by analyzing permitted base-pairing patterns, we could model RNA structure motifs that are crucial for protein binding.