486 resultados para Onsager reaction field approximation


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This paper describes the instigation and development of an expert system to aid in the strategic planning of construction projects. The paper consists of four parts - the origin of the project, the development of the concepts needed for the proposed system, the building of the system itself, and assessment of its performance. The origin of the project is outlined starting with the Japanese commitment to 5th generation computing together with the increasing local reaction to theory based prescriptive research in the field. The subsequent development of activities via the Alvey Commission and the RICS in conjunction with Salford University are traced culminating in the proposal and execution of the first major expert system to be built for the UK construction industry, subsequently recognised as one of the most successful of the expert system projects commissioned under the Alvey programme

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It is often suggested that there is a psychological advantage to be leading in a competition. It is, however, hard to identify such an effect econometrically. Using a Regression Discontinuity Design over a large dataset of tennis matches (N=634,095) the present paper exploits the randomised variation in first set results that occurs when the first set is decided by a close tie break (N=72,294). I find that winning the first set has a significant and strong effect on the result of the second set. A player who wins a close first set tie break will, on average, win one game more in the second set. I discuss the likely economic and psychological explanations of this phenomenon.

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The concept of market-driven rather than product-driven quality management has been given prominence through the report of a recent inquiry into the performance of the Hong Kong construction industry. The report submitted to the Government of Hong Kong in 2001 establishes a new vision of ‘an integrated industry that is capable of continuous improvement towards excellence in the market-driven environment’. Given the current economic downturn, major contractors are facing many challenges to realize this new quality oriented vision. This paper addresses the critical and timely issue of applying quality management to the project delivery process in Hong Kong. The paper attempts to capture and critically examine management perceptions of quality management aspects as applied to a local large-scale road construction project. Based on the analysis of questionnaire feedback and face-to-face interviews, the paper reveals key attributes of a successful application of quality management approaches, and identifies a mechanism for facilitating such implementation.

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In this paper, we consider a space fractional advection–dispersion equation. The equation is obtained from the standard advection–diffusion equation by replacing the first- and second-order space derivatives by the Riesz fractional derivatives of order β1 ∈ (0, 1) and β2 ∈ (1, 2], respectively. The fractional advection and dispersion terms are approximated by using two fractional centred difference schemes. A new weighted Riesz fractional finite-difference approximation scheme is proposed. When the weighting factor θ equals 12, a second-order accuracy scheme is obtained. The stability, consistency and convergence of the numerical approximation scheme are discussed. A numerical example is given to show that the numerical results are in good agreement with our theoretical analysis.

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Fractional reaction–subdiffusion equations are widely used in recent years to simulate physical phenomena. In this paper, we consider a variable-order nonlinear reaction–subdiffusion equation. A numerical approximation method is proposed to solve the equation. Its convergence and stability are analyzed by Fourier analysis. By means of the technique for improving temporal accuracy, we also propose an improved numerical approximation. Finally, the effectiveness of the theoretical results is demonstrated by numerical examples.

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Field-effect transistors (FETs) fabricated from undoped and Co2+-doped CdSe colloidal nanowires show typical n-channel transistor behaviour with gate effect. Exposed to microscope light, a 10 times current enhancement is observed in the doped nanowire-based devices due to the significant modification of the electronic structure of CdSe nanowires induced by Co2+-doping, which is revealed by theoretical calculations from spin-polarized plane-wave density functional theory.

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Urban and regional planners, in the era of globalization, require being equipped with necessary skill sets to better deal with complex and rapidly changing economic, sociocultural, political, and environmental fabrics of cities and their regions. To provide such skill sets, urban and regional planning curriculum of Queensland University of Technology, Brisbane, Australia, offers planning practice in the international context. This article, first, reports the findings of pedagogic analyses of the international field trips conducted to Malaysia, Korea, Turkey, and Taiwan. The article, then, discusses the opportunities and constraints of exposure of students to planning practice beyond the Australian context.

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This practice-based presentation explores the role of fashion as an agent for social inclusion and ethical design practice in communities. The Stitchery Collective is an artist-run initiative based in Brisbane, Australia. Operating at the intersection of craft and design, the fashion-based initiative challenges the assumption that fashion is designed, produced and consumed exclusively in the commercial sector. As a not-for-profit cooperative, the stitchery collective is the first and only fashion organisation in Australia to attract funding under the national and state artist-run-initiative scheme. The collective approach extends to the stitchery design practice, facilitated by individual practitioners working within the organisation who devise programs in the context of collaborative and socially engaged design. Working under the banner of a question, Can fashion be more than pretty clothes for pretty people? the stitchery works to extend the cultural field of fashion practice in the 21st century. The premise of dress as a ‘significant creative or cultural expression’ has informed the expanded definition of fashion practice, as adopted by the stitchery. This alternative classification has fostered partnerships with numerous community groups, including those marginalised in the contemporary fashion context such as recent migrants and refugees. Community engagement programs span design, sewing and up-cycling workshops, sustainability lectures, clothing swaps and public education seminars, supported by partnerships with various cultural, government and educational institutions. In 2011, the stitchery travelled to the Venice Biennale’s 3rd International Children’s Carnival, hosting a workshop series and installation to promote design for sustainability. The proven potential for design to connect community members has motivated the stitchery to question the opportunity for fashion practice to, perhaps uncharacteristically, operate under the banner of ‘design for social good’. Acknowledging craft and design as relational fields, this presentation expands fashion as a tool for social innovation and sustainable practice. The stitchery dislocates the consumer status of fashion with small-scale, localised projects; moving beyond fashion as a dictum of social class to an alternative model that is accessible, conscious, flexible, connected and sustainable. As an undefined post-industrial future approaches, the non-commercial status of the stitchery practice might work to present an image of the active post-consumer. How can the stitchery propose a resilient model of design for the future?

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Growing food presents diverse challenges and opportunities within the urban environment. As cities develop, population density rises, land prices rise, and the opportunity to use land for traditional farming and gardening diminishes. Counter to this trend there are a growing number of both community gardens, city farms, guerrilla gardening, rooftop and vertical gardens, pot plants, windowsill herbs, and other balcony or backyard gardens cropping up in different cities, all with a purpose to produce food. This workshop brings to-gether practitioners and researchers in the field of urban agriculture and Hu-man-Computer Interaction to explore and opportunities for technology design to support the different forms of growing practice and foster local food production in cities. This 1-day workshop will serve as an active forum for researchers and practi-tioners across various fields including, but not limited to, agriculture and gar-dening, education, urban planning, human-computer interaction, and communi-ty engagement. This workshop has three distinct points of focus: i) Individual and small-scale gardening and food production, and how to connect like minded people who are involved in these practices to share their knowledge ii) Com-munities involved in urban agriculture, either through community gardens, city farms, or grassroots movements, often dependant on volunteer participation, providing the challenge of managing limited resources iii) Environmental and sociocultural sustainability through urban agriculture. The participants will have an opportunity to present their own work. This will be followed by a visit to a nearby city farm, which will provide a local context for a group design exercise. Finally the workshop will conclude with panel dis-cussions to review opportunities for further research and collaborations beyond the conference. For more information, please visit the workshop website, at http://www.urbaninformatics.net/resources/interact2013cfp/

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LiFePO4 is a commercially available battery material with good theoretical discharge capacity, excellent cycle life and increased safety compared with competing Li-ion chemistries. It has been the focus of considerable experimental and theoretical scrutiny in the past decade, resulting in LiFePO4 cathodes that perform well at high discharge rates. This scrutiny has raised several questions about the behaviour of LiFePO4 material during charge and discharge. In contrast to many other battery chemistries that intercalate homogeneously, LiFePO4 can phase-separate into highly and lowly lithiated phases, with intercalation proceeding by advancing an interface between these two phases. The main objective of this thesis is to construct mathematical models of LiFePO4 cathodes that can be validated against experimental discharge curves. This is in an attempt to understand some of the multi-scale dynamics of LiFePO4 cathodes that can be difficult to determine experimentally. The first section of this thesis constructs a three-scale mathematical model of LiFePO4 cathodes that uses a simple Stefan problem (which has been used previously in the literature) to describe the assumed phase-change. LiFePO4 crystals have been observed agglomerating in cathodes to form a porous collection of crystals and this morphology motivates the use of three size-scales in the model. The multi-scale model developed validates well against experimental data and this validated model is then used to examine the role of manufacturing parameters (including the agglomerate radius) on battery performance. The remainder of the thesis is concerned with investigating phase-field models as a replacement for the aforementioned Stefan problem. Phase-field models have recently been used in LiFePO4 and are a far more accurate representation of experimentally observed crystal-scale behaviour. They are based around the Cahn-Hilliard-reaction (CHR) IBVP, a fourth-order PDE with electrochemical (flux) boundary conditions that is very stiff and possesses multiple time and space scales. Numerical solutions to the CHR IBVP can be difficult to compute and hence a least-squares based Finite Volume Method (FVM) is developed for discretising both the full CHR IBVP and the more traditional Cahn-Hilliard IBVP. Phase-field models are subject to two main physicality constraints and the numerical scheme presented performs well under these constraints. This least-squares based FVM is then used to simulate the discharge of individual crystals of LiFePO4 in two dimensions. This discharge is subject to isotropic Li+ diffusion, based on experimental evidence that suggests the normally orthotropic transport of Li+ in LiFePO4 may become more isotropic in the presence of lattice defects. Numerical investigation shows that two-dimensional Li+ transport results in crystals that phase-separate, even at very high discharge rates. This is very different from results shown in the literature, where phase-separation in LiFePO4 crystals is suppressed during discharge with orthotropic Li+ transport. Finally, the three-scale cathodic model used at the beginning of the thesis is modified to simulate modern, high-rate LiFePO4 cathodes. High-rate cathodes typically do not contain (large) agglomerates and therefore a two-scale model is developed. The Stefan problem used previously is also replaced with the phase-field models examined in earlier chapters. The results from this model are then compared with experimental data and fit poorly, though a significant parameter regime could not be investigated numerically. Many-particle effects however, are evident in the simulated discharges, which match the conclusions of recent literature. These effects result in crystals that are subject to local currents very different from the discharge rate applied to the cathode, which impacts the phase-separating behaviour of the crystals and raises questions about the validity of using cathodic-scale experimental measurements in order to determine crystal-scale behaviour.

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The research reported here addresses the problem of athlete off-field behaviours as they influence sports’ sponsors, particularly the achievement of sponsorship objectives. The question arises because of incidents of sponsorship contract cancellation following news-media reporting of athletes’ off-field behaviours. Two studies are used to investigate the research question; the first establishes the content of news-media reports, and the second tests the effects of news’ reports on athlete, team and sponsor evaluations using an experimental design. Key assumptions of the research are that sponsorship objectives are principally consumer-based and mediated. Models of sponsorship argue that sponsors aim to reach and influence consumers through sponsees. Assuming this pathway exists is central to sponsorship activities. A corollary is that other mediators, in this case the news-media, may also communicate (uncontrollable) messages such that a consumer audience may be told of negative news that may then be associated with the sponsor. When sponsors cancel contracts it is assumed that their goal is to control the links between their brand and a negative referent. Balance theory is used to discuss the potential effects of negative off-field behaviours of athletes on sponsor’s objectives. Heider’s balance theory (1958) explains that individuals prefer to evaluate linked individuals or entities consistently. In the sponsorship context this presents the possibility that a negative evaluation of the athlete’s behaviour will contribute to correspondingly negative evaluations of the athlete’s team and sponsors. A content analysis (Study 1) was used to survey the types of athlete off-field behaviours commonly reported in a newspaper. In order to provide a local context for the research, articles from the Courier Mail were sampled and teams in the National Rugby League (NRL) competition were the focus of the research. The study identified nearly 2000 articles referring to the NRL competition; 258 of those refer to off-field incidents involving athletes. The various types of behaviours reported include assault, sexual assault allegations, driving under the influence of alcohol, illicit drug use, breaches of club rules, and positive off-field activities (i.e., charitable activities). An experiment (Study 2) tested three news’ article stimuli developed from the behaviours identified in Study 1 in a between-subjects design. A measure of Identification with the Team was used as a covariate variable in the Multivariate Analysis of Covariance analysis. Social identity theory suggests that when an individual identifies with a group, their attitudes and behaviours towards both in- and out-group members are modified. Use of Identification with the Team as a covariate acknowledges that respondents will evaluate behaviours differently according to the attribution of those behaviours to an in- or out-group member. Findings of the research suggest that the news’ article stimuli have significant, large effects on evaluations of athlete off-field behaviour and athlete Likability. Consistent with pretest results, charitable fundraising is regarded as extremely positive; the athlete, correspondingly, is likable. Assault is evaluated as extremely negative, and the athlete as unlikable. DUI scores reveal that the athlete’s behaviour is very negative; however, the athlete’s likability was evaluated as neutral. Treatment group does not produce any significant effects on team or sponsor variables. This research also finds that Identification with the Team has significant, large effects on team variables (Attitude toward the Brand and Corporate Image). Identification also has a significant large effect on athlete Likability, but not on Attitude toward the Act. Identification with the Team does not produce any significant effects on sponsor variables. The results of this research suggest that sponsor’s consumer-based objectives are not threatened by newspaper reports linking athlete off-field behaviour with their brand. Evaluations of sponsor variables (Attitude toward the Sponsor’s Brand and Corporate Image) were consistently positive. Variance in that data, however, cannot be attributed to experimental stimuli or Identification with the Team. These results argue that respondents may regard sponsorships, in principle, as good. Although it is good news for sponsors that negative evaluations of athletes will not produce correspondingly negative evaluations of consumer-based sponsorship objectives, the results indicate problems for sponsorship managers. The failure of Identification with the Team to explain sponsor variable variance indicates that the sponsor has not been evaluated as a linked entity in a relationship with the sporting team and athlete in this research. This result argues that the sponsee-mediated affective communication path that sponsors aim use to communicate with desirable publics is not necessarily a path available to them.

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Due to their small collecting volume diodes are commonly used in small field dosimetry. However the relative sensitivity of a diode increases with decreasing small field size. Conversely, small air gaps have been shown to cause a significant decrease in the sensitivity of a detector as the field size is decreased. Therefore this study uses Monte Carlo simulations to look at introducing air upstream to diodes such that they measure with a constant sensitivity across all field sizes in small field dosimetry. Varying thicknesses of air were introduced onto the upstream end of two commercial diodes (PTW 60016 photon diode and PTW 60017 electron diode), as well as a theoretical unenclosed silicon chip using field sizes as small as 5 mm × 5 mm . The metric D_(w,Q)/D_(Det,Q) used in this study represents the ratio of the dose to a point of water to the dose to the diode active volume, for a particular field size and location. The optimal thickness of air required to provide a constant sensitivity across all small field sizes was found by plotting D_(w,Q)/D_(Det,Q) as a function of introduced air gap size for various field sizes, and finding the intersection point of these plots. That is, the point at which D_(w,Q)/D_(Det,Q) was constant for all field sizes was found. The optimal thickness of air was calculated to be 3.3 mm, 1.15 mm and 0.10 mm for the photon diode, electron diode and unenclosed silicon chip respectively. The variation in these results was due to the different design of each detector. When calculated with the new diode design incorporating the upstream air gap, k_(Q_clin 〖,Q〗_msr)^(f_clin 〖,f〗_msr ) was equal to unity to within statistical uncertainty (0.5 %) for all three diodes. Cross-axis profile measurements were also improved with the new detector design. The upstream air gap could be implanted on the commercial diodes via a cap consisting of the air cavity surrounded by water equivalent material. The results for the unclosed silicon chip show that an ideal small field dosimetry diode could be created by using a silicon chip with a small amount of air above it.

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The sidewall additions of diazomethane to (n, n), n = 3–10 armchair single-walled carbon nanotubes (SWCNTs) on two different orientations of C–C bonds have been studied using the ONIOM(B3LYP/6-31G(d):PM3) approach. The binding energies of SWCNTs complexes with CH2N2, CH2 and their transition-state structures were computed at the B3LYP/6-31G(d) level. The effects of diameters of armchair SWCNTs on their binding energies were studied. Relative reactivities of all the SWCNTs and their complexes based on their frontier orbital energies gaps are reported.

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Qualitative researchers in the discipline of criminology perform a wide range of challenging tasks. They interview prisoners, police officers, magistrates and judges. They speak with survivors of domestic violence, and drink tea with the mothers of murdered children. They observe courts and communities, investigate the decision-making processes of juries and immerse themselves in the data they collect. They ask ‘big’ questions – ‘how do we criminalise the producers of toxic toys?’ – as well as ‘little’ questions – ‘what should I wear to conduct this interview?’ Qualitative Criminology: Stories from the Field brings to life the stories behind the research of both emerging and established scholars in Australian criminology. The book’s contributors provided honest, reflective, and decidedly unsanitised accounts of their qualitative research journeys - the lively tales of what really happens when conducting research of this nature, the stories that often make for parenthetical asides in conference papers but tend to be excised from journal articles. This book considers the gap between research methods and the realities of qualitative research. As such, it aims to help researchers and students who conduct qualitative criminological research reflect upon their role as researchers, and the practical, ideological and ethical issues which may arise in the course of their research. It is also a call to criminologists to make public the ‘failures’ and missteps of their research endeavours so that we can learn from one another and become better informed and more reflexive qualitative criminologists.