Proposed formulas for evaluation of the equivalent material properties of a multiholed structure

It is widely known that the development of fine mesh in the immediate vicinity of the holes in a multiholed plate is a challenging issue. In practice, due to the amount of time consumed and the quality of the modelling, it is not desirable to model the structural characteristics of a multiholed plate in detail. In this regard, an effective means by which to avoid the unnecessary work of simulating a multiholed plate is to replace it with an equivalent solid plate while considering the decrease in stiffness associated with the increasing area of the holes. The objective of this study is to numerically and experimentally investigate the equivalent material properties of a multiholed plate of stainless steel 316L with respect to ligament efficiencies. Simple design formulas are proposed to determine the equivalent material properties of a multiholed plate that is completely perforated with closely spaced circular holes in a square or diagonal pattern by means of nonlinear finite-element method computations. It is concluded that the proposed formulas are accurate for prediction of the equivalent material properties of multiholed structures for their design and engineering

Unraveling the Cationic and Anionic Redox Reactions in a Conventional Layered Oxide Cathode

Increasing interest in high-energy lithium-ion batteries has triggered the demand to clarify the reaction mechanism in battery cathodes during high-potential operation. However, the reaction mechanism often involves both transition-metal and oxygen activities that remain elusive. Here we report a comprehensive study of both cationic and anionic redox mechanisms of LiNiO2 nearly full delithiation. Selection of pure LiNiO2 removes the complication of multiple transition metals. Using combined X-ray absorption spectroscopy, resonant inelastic X-ray scattering, and operando differential electrochemical mass spectrometry, we are able to clarify the redox reactions of transition metals in the bulk and at the surface, reversible lattice oxygen redox, and irreversible oxygen release associated with surface reactions. Many findings presented here bring attention to different types of oxygen activities and metal-oxygen interactions in layered oxides, which are of crucial importance to the advancement of a Ni-rich layered oxide cathode for high capacity and long cycling performance

A Framework for Decoupling Human Need Satisfaction From Energy Use

Climate change poses great challenges to modern societies, central amongst which is to decouple human need satisfaction from energy use. Energy systems are the main source of greenhouse gas emissions, and the services provided by energy (such as heating, power, transport and lighting) are vital to support human development. To address this challenge, we advocate for a eudaimonic need-centred understanding of human well-being, as opposed to hedonic subjective views of well-being. We also argue for a shift in the way we analyse energy demand, from energy throughput to energy services. By adopting these perspectives on either end of the wellbeing-energy spectrum, a “double decoupling” potential can be uncovered. We present a novel analytic framework and showcase several methodological approaches for analysing the relationship between, and decoupling of, energy services and human needs. We conclude by proposing future directions of research in this area based on the analytic framework

Extremely cold and hot temperatures increase the risk of ischaemic heart disease mortality: epidemiological evidence from China.

OBJECTIVE: To examine the effects of extremely cold and hot temperatures on ischaemic heart disease (IHD) mortality in five cities (Beijing, Tianjin, Shanghai, Wuhan and Guangzhou) in China; and to examine the time relationships between cold and hot temperatures and IHD mortality for each city. DESIGN: A negative binomial regression model combined with a distributed lag non-linear model was used to examine city-specific temperature effects on IHD mortality up to 20 lag days. A meta-analysis was used to pool the cold effects and hot effects across the five cities. PATIENTS: 16 559 IHD deaths were monitored by a sentinel surveillance system in five cities during 2004-2008. RESULTS: The relationships between temperature and IHD mortality were non-linear in all five cities. The minimum-mortality temperatures in northern cities were lower than in southern cities. In Beijing, Tianjin and Guangzhou, the effects of extremely cold temperatures were delayed, while Shanghai and Wuhan had immediate cold effects. The effects of extremely hot temperatures appeared immediately in all the cities except Wuhan. Meta-analysis showed that IHD mortality increased 48% at the 1st percentile of temperature (extremely cold temperature) compared with the 10th percentile, while IHD mortality increased 18% at the 99th percentile of temperature (extremely hot temperature) compared with the 90th percentile. CONCLUSIONS: Results indicate that both extremely cold and hot temperatures increase IHD mortality in China. Each city has its characteristics of heat effects on IHD mortality. The policy for response to climate change should consider local climate-IHD mortality relationships

An improved procedure for generating standardised load-time histories for marine structures

The load sequence effect has been proved from laboratory tests to be an influencing factor that cannot be neglected in the fatigue analysis of marine structures. To take account of this significant factor, fatigue life prediction should be based on fatigue crack propagation theory rather than the currently used cumulative fatigue damage theory. Accordingly, fatigue loading needs to be provided as the load-time history in the time domain rather than the load spectrum in the frequency domain. A general procedure for generating the standardised load-time history for marine structures based on a short-term load measurement has been proposed by the authors. This article seeks to further improve on this procedure and explain how to apply the determined standardised load-time history in the fatigue life prediction method based on the fatigue crack propagation theory. Finally, generation and application of a standardised load-time history are given for a tubular T-joint of an offshore platform, which demonstrates the practical and effective use of the proposed approach

Coherent oscillations and giant edge magnetoresistance in singly connected topological insulators

A topological insulator has a pair of extended states at the edge in the bulk insulating regime. We study a geometry in which such edge states will manifest themselves in a qualitative manner through periodic oscillations in the magnetoconductance of a singly connected sample coupled to leads through narrow point contacts. Detailed calculations identify the parameters for which these oscillations are expected to be the strongest, and also show their robustness to disorder. Such oscillations can be used as a spectroscopic tool of the edge states. A large change in the device resistance at small B, termed giant edge magnetoresistance, can have potential for application. © 2009 The American Physical Society.published_or_final_versio

Human Scale Energy Services: Untangling a ‘golden thread’

Prioritising human well-being while avoiding further damage to the planet is a key challenge in the era of climate change. This paper examines the role of energy as an intermediary between climate change and socio-economic outcomes, with the ultimate goal of identifying ways of decoupling human well-being from energy use. Building on Max-Neef’s “Human Scale Development” framework and conceptualisation of human needs, we propose a novel community-level participatory approach to identify connections between energy services on the one hand and human need satisfaction on the other. This approach then enables communities to collectively consider and propose alternative ways to provide energy services. We compare the outcomes and reflect on the process of two exploratory workshops, undertaken in an urban and a rural area in Medellín (Colombia). Our results indicate that these communities view energy services as satisfiers of human needs, with significant differences between the communities. Furthermore, our approach enables the communities to broaden the solution space of energy service provisioning possibilities, thus constituting a promising alternative to the top-down technocratic perspectives currently prevalent in research and policy. We argue that this type of bottom-up approach is necessary to address the complex sustainability challenge of living well within environmental limits

Envelope Determinants of Equine Lentiviral Vaccine Protection

Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection. © 2013 Craigo et al

Degradation of metaldehyde in water by nanoparticle catalysts and powdered activated carbon

Metaldehyde, an organic pesticide widely used in the UK, has been detected in drinking water in the UK with a low concentration (<1 μg L−1) which is still above the European and UK standard requirements. This paper investigates the efficiency of four materials: powdered activated carbon (PAC) and carbon-doped titanium dioxide nanocatalyst with different concentrations of carbon (C-1.5, C-40, and C-80) for metaldehyde removal from aqueous solutions by adsorption and oxidation via photocatalysis. PAC was found to be the most effective material which showed almost over 90% removal. Adsorption data were well fitted to the Langmuir isotherm model, giving a qm (maximum/saturation adsorption capacity) value of 32.258 mg g−1 and a KL (Langmuir constant) value of 2.013 L mg−1. In terms of kinetic study, adsorption of metaldehyde by PAC fitted well with a pseudo-second-order equation, giving the adsorption rate constant k2 value of 0.023 g mg−1 min−1, implying rapid adsorption. The nanocatalysts were much less effective in oxidising metaldehyde than PAC with the same metaldehyde concentration and 0.2 g L−1 loading concentration of materials under UV light; the maximum removal achieved by carbon-doped titanium dioxide (C-1.5) nanocatalyst was around 15% for a 7.5 ppm metaldehyde solution