Springback investigation in roll forming of a V-section

To have fuel efficient vehicles with a lightweight structure, the use of High Strength Steels (HSS) and Advanced High Strength Steels (AHSS) in the body of automobiles is increasing. Roll forming is used widely to form AHSS materials. Roll forming is a continuous process in which a flat strip is shaped to the desired profile by passing through numerous sets of rolls. Formability and springback are two major concerns in the roll forming of AHSS materials. Previous studies have shown that the elastic modulus (Young's modulus) of AHSS materials can change when the material undergoes plastic deformation and the main goal of this study is to numerically investigate the effect of a change in elastic modulus during forming on springback in roll forming. Experimental loading-unloading tests have been performed to obtain the material properties of TRIP 700 steel and incorporate those in the material model used in the numerical simulation of the roll forming process. The finite element simulations were carried out using MSC-Marc and two different element types, a shell element and a solid-shell element, were investigated. The results show that the elastic modulus diminution due to plastic strain increases the springback angle by about 60% in the simple V-section roll forming analyzed in this study. © (2014) Trans Tech Publications, Switzerland.

The inter-section of political history and health policy in Asia - the historical foundations for health policy analysis

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.

Panicca: panic on cross-section averages

The cross-section average (CA) augmentation approach of Pesaran (2007) and Pesaran et al. (2013), and the principal components-based panel analysis of non-stationarity in idiosyncratic and common components (PANIC) of Bai and Ng (2004, 2010) are among the most popular “second-generation” approaches for cross-section correlated panels. One feature of these approaches is that they have different strengths and weaknesses. The purpose of the current paper is to develop PANICCA, a combined approach that exploits the strengths of both CA and PANIC.

Welcome from the policies, socio-economic aspects, and health systems research section

At BMC Obesity, the Policies, Socio-economic Aspects, and Health Systems Research Section provides an opportunity to submit research focussed on what we need to know to support implementation of obesity policies most likely to achieve substantial, sustainable and equitable reductions in the prevalence of obesity globally. Here, we present the aims and objectives of this section, hearing from each of the Associate Editors in turn. The ambition of the Policies, Socio-economic Aspects, and Health Systems Research Section is to foster innovative research combining scientific quality with real world experience. We envisage this will include research addressing the structural drivers of obesity, solution oriented research, research addressing socio-economic inequalities in obesity and obesity prevention in low and middle income countries. We look forward to stimulating research to advance both the methods and substance required to drive uptake of effective and equitable obesity reduction policies globally.

A new Changhsingian (Late Permian) brachiopod fauna from the Zhongzhai section (South China) Part 3: Productida

Zhang, Y., He, W.H., Shi, G.R., Zhang, K.X. & Wu, H.T., 26.2.2015. A new Changhsingian (Late Permian) brachiopod fauna from the Zhongzhai section (South China) Part 3: Productida. Alcheringa 39, xxx–xxx. ISSN 0311-5518. As the third and last part of a systematic palaeontological study of the brachiopod fauna from the Permian–Triassic boundary section at Zhongzhai in Guizhou Province (South China), this paper reports 15 species (including three new species: Tethyochonetes minor sp. nov., Neochonetes (Zhongyingia) transversa sp. nov., Paryphella acutula sp. nov.) in Order Productida. In addition, the morphological features and definitions of several key Changhsingian brachiopod taxa (e.g., Paryphella and Oldhamina interrupta) are clarified and revised.

Fluctuations of redox conditions across the Permian–Triassic boundary : new evidence from the GSSP section in Meishan of South China

Oceanic anoxia has long been considered as one of the main causes for the end-Permian mass extinction. However, the results obtained by different researchers are rather divergent from different sections, or even on the same section using the same redox proxy. This study aims to examine the causes for some of these divergent results using high-resolution pyrite framboid sampling at the Meishan GSSP section in South China. Detailed microfacies analysis shows that the uppermost Late Permian strata comprises two significantly different sedimentary facies: one characterized by silicious muddy limestone and recognized as representing autochthonous background sediments; the other distinguished by bioclastic grainstone, interpreted to be allochthonous in origin and have been transported from the nearby platform margin. These two different sedimentary facies represent two distinctly different redox conditions. Together with the facies analysis, a statistical analysis of pyrite framboids was carried out to evaluate the redox evolution across the Permian-Triassic boundary. Abundant framboids with average diameters of about 6μm are found in background sediments beneath the extinction boundary, indicating generally anoxic bottom water conditions. But this condition was punctuated by transient intervals of rapid oxygenation interpreted to have been caused by intrusion of intermittent turbidity flows. Our study also showed that anoxic conditions persisted into the immediate aftermath of the mass extinction, thereafter it was quickly followed by a relatively long period of oxic conditions (with rare framboids). However, the redox conditions returned to anoxia (with abundant pyrite framboids averaging about 5μm in diameter), accompanied by a rapid global transgression. The oxygenation manifested near the Permian-Triassic boundary coincides with the negative excursion of carbon isotope. This would imply that, contrary to previous interpretations, this great δ13C negative excursion was probably not caused by the upwelling of anoxic deep ocean waters.

Patterns of brachiopod faunal and body-size changes across the Permian-Triassic boundary: Evidence from the Daoduishan section in Meishan area, South China

New analysis of Permian-Triassic brachiopod assemblages and body-size changes in South China provides insights into the process of the environmental crisis in the lead up to the end-Permian mass extinction. The recently discovered Daoduishan section of South China can be considered as an important auxiliary section for the study of brachiopods at the Meishan Section D of South China, the GSSP of the Permian-Triassic Boundary (PTB). This paper studied changes of the brachiopod assemblages and body sizes through the upper part of the Changxing Formation and basal Yinkeng Formation of Daoduishan. The results show that significant changes of brachiopod assemblages took place between Beds 24e and 26. Brachiopods?Prelissorhynchia sp. and Paracruirithyris pygmaea are the dominators in Beds 14-24e, while Tethyochonetes pigmaea and Paryphella spp. are the dominators in Beds 26-29. Body sizes of brachiopods significantly decreased between Beds 24e and 26 and then maintained smaller means in Beds 27-29. Studies of brachiopod morphological features indicate both Tethyochonetes and Paryphella had advantageous adaptations enabling them to copy with living in an anoxic/dysoxic and/or low-productivity environment during the Permian-Triassic crisis.

Aggregate volatility risk and the cross-section of stock returns: Australian evidence

This study examines the relation between aggregate volatility risk and the cross-section of stock returns in Australia. We use a stock's sensitivity to innovations in the ASX200 implied volatility (VIX) as a proxy for aggregate volatility risk. Consistent with theoretical predictions, aggregate volatility risk is negatively related to the cross-section of stock returns only when market volatility is rising. The asymmetric volatility effect is persistent throughout the sample period and is robust after controlling for size, book-to-market, momentum, and liquidity issues. There is some evidence that aggregate volatility risk is a priced factor, especially in months with increasing market volatility.

In Their Footsteps, In Their Words: Special Section, 1813-1863

In Their Footsteps and In Their Words: Colby explores the first 50 years, from Jeremiah Chaplin to the Civil War.

Using Interlibrary Loan Data as a Section Tool: ILL Trails Provide Collection Clues

This article describes analyzing Interlibrary Loan data to help inform collection management decision and offers guidance for formulating policies for discerning borrowed titles indicative of gaps in the library from special-interest pursuits beyond the scope of the university curriculum.