998 resultados para RADIOACTIVE ELEMENTS


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Axial shortening in vertical load bearing elements of reinforced concrete high-rise buildings is caused by the time dependent effects of shrinkage, creep and elastic shortening of concrete under loads. Such phenomenon has to be predicted at design stage and then updated during and after construction of the buildings in order to provide mitigation against the adverse effects of differential axial shortening among the elements. Existing measuring methods for updating previous predictions of axial shortening pose problems. With this in mind, a innovative procedure with a vibration based parameter called axial shortening index is proposed to update axial shortening of vertical elements based on variations in vibration characteristics of the buildings. This paper presents the development of the procedure and illustrates it through a numerical example of an unsymmetrical high-rise building with two outrigger and belt systems. Results indicate that the method has the capability to capture influence of different tributary areas, shear walls of outrigger and belt systems as well as the geometric complexity of the building.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Radioactive wastes are by-products of the use of radiation technologies. As with many technologies, the wastes are required to be disposed of in a safe manner so as to minimise risk to human health. This study examines the requirements for a hypothetical repository and develops techniques for decision making to permit the establishment of a shallow ground burial facility to receive an inventory of low-level radioactive wastes. Australia’s overall inventory is used as an example. Essential and desirable siting criteria are developed and applied to Australia's Northern Territory resulting in the selection of three candidate sites for laboratory investigations into soil behaviour. The essential quantifiable factors which govern radionuclide migration and ultimately influence radiation doses following facility closure are reviewed. Simplified batch and column procedures were developed to enable laboratory determination of distribution and retardation coefficient values for use in one-dimensional advection-dispersion transport equations. Batch and column experiments were conducted with Australian soils sampled from the three identified candidate sites using a radionuclide representative of the current national low-level radioactive waste inventory. The experimental results are discussed and site soil performance compared. The experimental results are subsequently used to compare the relative radiation health risks between each of the three sites investigated. A recommendation is made as to the preferred site to construct an engineered near-surface burial facility to receive the Australian low-level radioactive waste inventory.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is a widespread recognition to the need of better manage municipal property in most cities in the world. Structural problems across regional, state, and territorial governments that have legal powers to own and maintain real property are similar, regardless of the level of development of each country. Start from a very basic level of property inventory records. The need for better manage to the local government owned property is the result of widespread decentralisation initiatives that often have devolved huge property portfolios from central to local governments almost “overnight”. At the same time municipal or regional governments were and continue to be unprepared to deal with multiple issues related to the role of property owners and managers. The lack of discussion of public asset management especially the elements that should be incorporated in the framework creates an important challenge to study the discipline of public asset management further. The aim of this paper is to study the practices of public asset management in developed countries, especially the elements of public asset management framework, and its transferability to developing countries. A case study was selected and conducted to achieve this aim. They involved interviews and a focus group. The study found that in public asset management framework, proper asset identification, public asset needs analysis, asset life cycle and performance measurements are an important element that should be incorporated in the framework. Those elements are transferable and applicable to developing countries’ local governments. Finally, findings from this study provide useful input for the local government policy makers, scholars and asset management practitioners to establish a public asset management framework toward more efficient and effective local governments in managing their assets as well as increasing public services quality.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

It is noted from observations of Compton (2009), Richards (2008), Taylor and Bennett (2002), and others that succession leadership planning and development fails to receive adequate attention in the corporate sector (see Byham 2002; Richards 2008; Wellins and Byham 2001). This paper acknowledges a marked paucity of systematic succession leadership development in education organisations. The need would seem to be compounded at a time when substantial attrition in the leadership ranks is expected over the next five years, reflecting widespread workforce demographics (Busine and Watt 2005; Jacobzone, Cambois, Chaplain, and Robine 1998; Taylor and Bennett 2002). The Lantern model has been developed in response to a perceived need to offer an integrated, systematic approach to organisational and succession leadership development. The model offers an organising framework for considering succession leadership development in a strategic, integrated way. The concept is based on organisational development and leadership literature which sees leadership development not as a series of 'tacked on' activities but as an organic 'whole of organisation' approach fostering the relevant knowledge, skills and understandings which support and 'grow' leaders as the organisation goes about its business. This paper explores how such an ideal might happen, and it suggests that pursuing such an ideal is timely. The leadership baton is set to shift at an accelerated rate in universities, as for organisations broadly, owing to age-related attrition. Moreover, given the increased complexity and demands of the leadership remit in the education leadership environment, it would seem particularly opportune to explore a framework concentrating on engendering a positive, connected organisational climate capable of growing strategic leadership strength from within. Eight core elements of the model, derived from the literature and practice research, are explored. The Lantern model purports to 'cover the bases' of succession leadership development, with particular reference to the education environment. The model is next described

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The concept of strategic entrepreneurship has received increased attention over the past ten yeras. Viewed as the intersection of entrepreneurship and strategy this field of research is populated by conceptual studies which focus mainly on the nature and perceived benefits of strategic entrepreneurship. Similarly the study of entrepreneurship in a public sector context has gained increasing support in recent years but also remains underexplored. To address these gaps this thesis considers : what are the underlying elements and financial implications of strategic entrepreneurship in New Zealand's state-owned enterprises, New Zealand's SOE sector comprising 17 government-owned,commercially focused organisations, is considered to be a prime subject for this research. Well known for their implementation of new public management, many New Zealand SOEs have also been publicly recognised as both innovative and entrepreneurial. The research question is addressed by first developing a preliminary framework of strategic entrepreneurship from literature on entrepreneurhsip and strategy. The framework is then examined in the context of case studies on activity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Sodium niobates doped with different amount of tantalum (TaV) were prepared via thermal reaction process. It was found pure nanofibril and bar-like solids can be obtained when tantalum was introduced into the reaction system. For the well-crystallized fibril solids, the Na+ ions are difficult to be exchanged, and the radioactive ions such as Sr2+ and Ra2+ ions just deposit on the surface of the fibers during the sorption process, resulting in lower sorption capacity and distribution coefficients (Kd)`. However, the bar-like solids are poorly-crystallized and have lots of exchangeable Na+ ions. They are able to remove highly hazardous bivalent radioactive isotopes such as Sr2+ and Ra2+ ions. Even in the presence of lots of Na+ ions, they also have higher Kd. More importantly, such sorption finally intelligently triggers considerable collapse of the structure, resulting in the entrapment of the toxic bivalent cations permanently in the solids so that they can be safely disposed. This study highlights new opportunities for the preparation of Nb-based adsorbents to efficiently remove the toxic radioactive ions from contaminated water.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the past eight years, Australia has adopted the use of environmental offsets as a means to compensate for environmental degradation from development. Queensland has more environmental offsetting policies than any other Australian State or Territory. The methodology has profound effects on development companies, landowners (both private and public), regional land planning, organizations, government agencies, monetary banking institutions and environmental conservation bodies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Axial deformations resulting from in-plane loads (axial forces) of plate elements impact significantly on their vibration characteristics. Although, numerous methods have been developed to quantify axial forces and hence deformations of individual plate elements with different boundary conditions based on their natural frequencies, these methods are unable to apply to the plate elements in a structural system. This is because the natural frequency is a global parameter for the entire structure. Thus, this paper proposes a comprehensive vibration based procedure to quantify axial deformations of plate elements in a structural framing system. Unique capabilities of the proposed method present through illustrative examples. Keywords- Plate Elements, Dynamic Stiffness Matrix, Finite Element Method, Vibration Characteristics, Axial Deformation