Numerical investigation of mechanical and thermal dynamic properties of the industrial transformer

Industrial transformer is one of the most critical assets in the power and heavy industry. Failures of transformers can cause enormous losses. The poor joints of the electrical circuit on transformers can cause overheating and results in stress concentration on the structure which is the major cause of catastrophic failure. Few researches have been focused on the mechanical properties of industrial transformers under overheating thermal conditions. In this paper, both mechanical and thermal properties of industrial transformers are jointly investigated using Finite Element Analysis (FEA). Dynamic response analysis is conducted on a modified transformer FEA model, and the computational results are compared with experimental results from literature to validate this simulation model. Based on the FEA model, thermal stress is calculated under different temperature conditions. These analysis results can provide insights to the understanding of the failure of transformers due to overheating, therefore are significant to assess winding fault, especially to the manufacturing and maintenance of large transformers.

A meshfree-based local Galerkin method with condensation of degree of freedom for elastic dynamic analysis

Condensation technique of degree of freedom is first proposed to improve the computational efficiency of meshfree method with Galerkin weak form for elastic dynamic analysis. In the present method, scattered nodes without connectivity are divided into several subsets by cells with arbitrary shape. Local discrete equation is established over each cell by using moving Kriging interpolation, in which the nodes that located in the cell are used for approximation. Then local discrete equations can be simplified by condensation of degree of freedom, which transfers equations of inner nodes to equations of boundary nodes based on cells. The global dynamic system equations are obtained by assembling all local discrete equations and are solved by using the standard implicit Newmark’s time integration scheme. In the scheme of present method, the calculation of each cell is carried out by meshfree method, and local search is implemented in interpolation. Numerical examples show that the present method has high computational efficiency and good accuracy in solving elastic dynamic problems.

Dynamic changes in high and low mammographic density human breast tissues maintained in murine tissue engineering chambers during various murine peripartum states and over time

Mammographic density (MD) is a strong heritable risk factor for breast cancer, and may decrease with increasing parity. However, the biomolecular basis for MD-associated breast cancer remains unclear, and systemic hormonal effects on MD-associated risk is poorly understood. This study assessed the effect of murine peripartum states on high and low MD tissue maintained in a xenograft model of human MD. Method High and low MD human breast tissues were precisely sampled under radiographic guidance from prophylactic mastectomy specimens of women. The high and low MD tissues were maintained in separate vascularised biochambers in nulliparous or pregnant SCID mice for 4 weeks, or mice undergoing postpartum involution or lactation for three additional weeks. High and low MD biochamber material was harvested for histologic and radiographic comparisons during various murine peripartum states. High and low MD biochamber tissues in nulliparous mice were harvested at different timepoints for histologic and radiographic comparisons. Results High MD biochamber tissues had decreased stromal (p = 0.0027), increased adipose (p = 0.0003) and a trend to increased glandular tissue areas (p = 0.076) after murine postpartum involution. Stromal areas decreased (p = 0.042), while glandular (p = 0.001) and adipose areas (p = 0.009) increased in high MD biochamber tissues during lactation. A difference in radiographic density was observed in high (p = 0.0021) or low MD biochamber tissues (p = 0.004) between nulliparous, pregnant and involution groups. No differences in tissue composition were observed in high or low MD biochamber tissues maintained for different durations, although radiographic density increased over time. Conclusion High MD biochamber tissues had measurable histologic changes after postpartum involution or lactation. Alterations in radiographic density occurred in biochamber tissues between different peripartum states and over time. These findings demonstrate the dynamic nature of the human MD xenograft model, providing a platform for studying the biomolecular basis of MD-associated cancer risk. © 2013 Springer Science+Business Media New York.

Reproductive technology, public policy and single motherhood

In mid 2000, the Australian community engaged in a national debate over access to infertility treatment services. The debate was sparked by a Federal Court decision in late July. That decision, by Justice Sundberg in the case of McBain v State of Victoria 1 held that the provisions of the Infertility Treatment Act 1995 (Vic) which limited eligibility for infertility treatment to women who were married or in heterosexual de facto relationships, were inconsistent with section 22 of the Commonwealth Sex Discrimination Act 1984 (Cth) which prohibits discrimination on the basis of marital status. Justice Sundberg held that, by virtue of section 109 of the Constitution, 2 the provisions of the Victorian Act were inoperative to the extent of the inconsistency between the State and Commonwealth legislation.

Aircraft dynamic navigation for unmanned aerial vehicles

This thesis describes the investigation of an Aircraft Dynamic Navigation (ADN) approach, which incorporates an Aircraft Dynamic Model (ADM) directly into the navigation filter of a fixed-wing aircraft or UAV. The result is a novel approach that offers both performance improvements and increased reliability during short-term GPS outages. This is important in allowing future UAVs to achieve routine, unconstrained, and safe operations in commercial environments. The primary contribution of this research is the formulation Unscented Kalman Filter (UKF) which incorporates a complex, non-linear, laterally and longitudinally coupled, ADM, and sensor suite consisting of a Global Positioning System (GPS) receiver, Inertial Measurement Unit (IMU), Electronic Compass (EC), and Air Data (AD) Pitot Static System.

Effect of vertical misalignment of adjacent sleepers on the increase in dynamic loads around rail joints

In spite of the extensive usage of continuous welded rails, a number of rail joints still exist in the track. Although a number of them exist as part of turnouts in the yards where the speed is not of concern, the Insultated Rail Joints (IRJs) that exist in ballasted tracks remain a source of significant impact loading. A portion of the dynamic load generated at the rail joints due to wheel passage is transmitted to the support system which leads to permanent settlements of the ballast layer with subsequent vertical misalignment of the sleepers around the rail joints. The vertical misalignment of the adjacent sleepers forms a source of high frequency dynamic load raisers causing significant maintenance work including localised grinding of railhead around the joint, re-alignment of the sleepers and/or ballast tamping or track component renewals/repairs. These localised maintenance activities often require manual inspections and disruptions to the train traffic loading to significant costs to the rail industry. Whilst a number of studies have modelled the effect of joints as dips, none have specifically attended to the effect of vertical misalignment of the sleepers on the dynamic response of rail joints. This paper presents a coupled finite element track model and rigid body track-vehicle interaction model through which the effects of vertical of sleepers on the increase in dynamic loads around the IRJ are studied. The finite element track model is employed to determine the generated dip from elastic deformations as well as the vertical displacement of sleepers around the joint. These data (dip and vertical misalignments) are then imported into the rigid body vehicle-track interaction model to calculate the dynamic loads.

Anti-wind-up designs for dynamic positioning of marine vehicles with control allocation

This paper presents a framework for the design of a joint motion controller and a control allocation strategy for dynamic positioning of marine vehicles. The key aspects of the proposed designs are a systematic approach to deal with actuator saturation and to inform the motion controller about saturation. The proposed system uses a mapping that translates the actuator constraint sets into constraint sets at the motion controller level. Hence, while the motion controller addresses the constraints, the control allocation algorithm can solve an unconstrained optimisation problem. The constrained control design is approached using a multivariable anti-wind-up strategy for strictly proper controllers. This is applicable to the implementation of PI and PID type of motion controllers.

Hidden innovation : Policy, industry and the creative sector

The term ‘two cultures’ was coined more than 50 years ago by scientist and novelist C.P. Snow to describe the divergence in the world views and methods of scientists and the creative sector. This divergence has meant that innovation systems and policies have focused for decades on science, engineering, technology and medicine and the industries that depend on them. The humanities, arts and social sciences have been bit players at best; their contributions hidden from research agendas, policy and program initiatives, and the public mind. But structural changes to advanced economies and societies have brought services industries and the creative sector to greater prominence as key contributors to innovation. Hidden Innovation peels back the veil, tracing the way innovation occurs through new forms of screen production enabled by social media platforms as well as in public broadcasting. It shows that creative workers are contributing fresh ideas across the economy and how creative cities debates need reframing. It traces how policies globally are beginning to catch up with the changing social and economic realities. In his new book, Cunningham argues that the innovation framework offers the best opportunity in decades to reassess and refresh the case for the public role of the humanities, particularly the media, cultural and communication studies disciplines.

Effects of child care policy and environment on physical activity

Child care centers differ systematically with respect to the quality and quantity of physical activity they provide, suggesting that center-level policies and practices, as well as the center's physical environment, are important influences on children's physical activity behavior. Purpose To summarize and critically evaluate the extant peer-reviewed literature on the influence of child care policy and environment on physical activity in preschool-aged children. Methods A computer database search identified seven relevant studies that were categorized into three broad areas: cross-sectional studies investigating the impact of selected center-level policies and practices on moderate-to-vigorous physical activity (MVPA), studies correlating specific attributes of the outdoor play environment with the level and intensity of MVPA, and studies in which a specific center-level policy or environmental attribute was experimentally manipulated and evaluated for changes in MVPA. Results Staff education and training, as well as staff behavior on the playground, seem to be salient influences on MVPA in preschoolers. Lower playground density (less children per square meter) and the presence of vegetation and open play areas also seem to be positive influences on MVPA. However, not all studies found these attributes to be significant. The availability and quality of portable play equipment, not the amount or type of fixed play equipment, significantly influenced MVPA levels. Conclusions Emerging evidence suggests that several policy and environmental factors contribute to the marked between-center variability in physical activity and sedentary behavior. Intervention studies targeting these factors are thus warranted.

The effect of multiplayer dynamic difficulty adjustment on the player experience of video games

Multiplayer Dynamic Difficulty Adjustment (mDDA) is a method of reducing the difference in player performance and subsequent challenge in competitive multiplayer video games. As a balance of between player skill and challenge experienced is necessary for optimal player experience, this experimental study investigates the effects of mDDA and awareness of its presence on player performance and experience using subjective and biometric measures. Early analysis indicates that mDDA normalizes performance and challenge as expected, but awareness of its presence can reduce its effectiveness.

Decoupling 2 : technologies, opportunities and policy options

This report was produced by the Decoupling Working Group of the International Resource Panel. It explores technological possibilities and opportunities for both developing and developed countries to accelerate decoupling and reap the environmental and economic benefits of increased resource productivity. It also examines several policy options that have proved to be successful in helping different countries to improve resource productivity in various sectors of their economy, avoiding negative impacts on the environment. It does not seem possible for a global economy based on the current unsustainable patterns of resource use to continue into the future. The economic consequences of these patterns are already apparent in three areas: increases in resource prices, increased price volatility and disruption of environmental systems. The environment impacts of resource use are also leading to potentially irreversible changes to the world’s ecosystems, often with direct effects on people and the economy – for example through damage to health, water shortages, loss of fish stocks or increased storm damage. But there are alternatives to these scary patterns. Many decoupling technologies and techniques that deliver resource productivity increases as high as 5 to 10-fold are already available, allowing countries to pursue their development strategies while significantly reducing their resource footprint and negative impacts on the environment. This report shows that much of the policy design “know-how” needed to achieve decoupling is present in terms of legislation, incentive systems, and institutional reform. Many countries have tried these out with tangible results, encouraging others to study and where appropriate replicate and scale up such practices and successes.

Literacy assessment that counts : mediating, interpreting and contesting translocal policy in a primary school

In Australia, as in many western education systems over the last two decades, discourses of accountability and performativity have reshaped education policy that has in turn reorganised the work of school leaders and teachers. One of the effects of this reorganisation is increased attention to the production, analysis and display of student achievement data. In this paper we examine in detail a sequence of the production and reading of literacy assessment data in a small Catholic school. Our analysis uses institutional ethnography’s concept of the ‘active text’, the text as occurring in a specific place and time even as it is articulated to social relations beyond its immediate context. Through this process we learn from those involved how their everyday work brings into being formalised, textually authorised processes in a local site that ensure the school meets accountability requirements while enabling teachers to resist standardisation of literacy teaching and assessment.

A dynamic in vivo model of epithelial-to-mesenchymal transitions in circulating tumor cells and metastases of breast cancer

Epithelial-to-mesenchymal transition (EMT) processes endow epithelial cells with enhanced migratory/invasive properties and are therefore likely to contribute to tumor invasion and metastatic spread. Because of the difficulty in following EMT processes in human tumors, we have developed and characterized an animal model with transplantable human breast tumor cells (MDA-MB-468) uniquely showing spontaneous EMT events to occur. Using vimentin as a marker of EMT, heterogeneity was revealed in the primary MDA-MB-468 xenografts with vimentin-negative and vimentin-positive areas, as also observed on clinical human invasive breast tumor specimens. Reverse transcriptase-PCR after microdissection of these populations from the xenografts revealed EMT traits in the vimentin-positive zones characterized by enhanced 'mesenchymal gene' expression (Snail, Slug and fibroblast-specific protein-1) and diminished expression of epithelial molecules (E-cadherin, ZO-3 and JAM-A). Circulating tumor cells (CTCs) were detected in the blood as soon as 8 days after s.c. injection, and lung metastases developed in all animals injected as examined by in vivo imaging analyses and histology. High levels of vimentin RNA were detected in CTCs by reverse transcriptase-quantitative PCR as well as, to a lesser extent, Snail and Slug RNA. Von Willebrand Factor/vimentin double immunostainings further showed that tumor cells in vascular tumoral emboli all expressed vimentin. Tumoral emboli in the lungs also expressed vimentin whereas macrometastases displayed heterogenous vimentin expression, as seen in the primary xenografts. In conclusion, our data uniquely demonstrate in an in vivo context that EMT occurs in the primary tumors, and associates with an enhanced ability to intravasate and generate CTCs. They further suggest that mesenchymal-to-epithelial phenomena occur in secondary organs, facilitating the metastatic growth.

Identifying the key sociocultural influences on drinking behavior in high and moderate binge-drinking countries and the public policy implications

Despite considerable state investment and initiatives, binge drinking is still a major behavioral problem for policy makers and communities in many parts of the world. Furthermore, the practice of bingeing on alcohol seems to be spreading to young people in countries traditionally considered to have moderate drinking behaviors. Using a sociocultural lens and a framework of sociocultural themes from previous literature to develop propositions from their empirical study, the authors examine binge-drinking attitudes and behaviors among young people from high and moderate binge-drinking countries. The authors then make proposals regarding how policy makers can use social marketing more effectively to contribute to behavior change. Qualitative interviews were conducted with 91 respondents from 22 countries who were studying in two high binge-drinking countries at the time. The results show support for three contrasting sociocultural propositions that identify influences on binge drinking across these countries.

Two dynamic discrete choice estimation problems and simulation method solutions

This paper considers two problems that frequently arise in dynamic discrete choice problems but have not received much attention with regard to simulation methods. The first problem is how to simulate unbiased simulators of probabilities conditional on past history. The second is simulating a discrete transition probability model when the underlying dependent variable is really continuous. Both methods work well relative to reasonable alternatives in the application discussed. However, in both cases, for this application, simpler methods also provide reasonably good results.