Mg2FeH6–LiBH4 and Mg2FeH6–LiNH2 composite materials for hydrogen storage

Two composite hydrogen storage materials based on Mg₂FeH₆ were investigated for the first time. The Mg₂FeH₆–LiBH₄ composite of molar ratio 1:5 showed a hydrogen desorption capacity of 5.6 wt.% at 370 °C, and could be rehydrogenated to 3.6 wt.% with the formation of MgH₂, as the material was heated to 445 °C and held at this temperature. The Mg₂FeH₆–LiNH₂ composite of 3:10 molar ratio exhibited a hydrogen desorption capacity of 4.3 wt.% and released hydrogen at 100 °C lower then the Mg₂FeH₆–LiBH₄ composite, but this mixture could not be rehydrogenated. Compared to neat Mg₂FeH₆, both composites show enhanced hydrogen storage properties in terms of desorption kinetics and capacity at these low temperatures. In particular, Mg₂FeH₆–LiNH₂ exhibits a much lower desorption temperature than neat Mg₂FeH₆, but only Mg₂FeH₆–LiBH₄ re-absorbs hydrogen.     

Footwear: Shoes and Boots from the Hopkins Collection

Abstract

This paper examines the influence that the costume designers of the Ballets Russes, many of whom were important artists from significant art movements of the day, had on contemporaneous fashion. It looks at why in particular the 'Ballets Russes' artists Leon Bakst and Natalia Goncharova went on to involve themselves in actual fashion production and the similarities between their work and the fashion designers producing work at the same time, principally Paul Poiret, Mariano Fortuny and Coco Chanel. Overall, this paper investigates the significance of the cultural times and of the distinct characteristics of the separate art forms, that may have encouraged avant-garde art and fashion to crossover and collaborate so unreservedly.     

Distributed dynamic load balancing with applications in radio access networks

Managing and balancing load in distributed systems remains a challenging problem in resource management, especially in networked systems where scalability concerns favour distributed and dynamic approaches. Distributed methods can also integrate well with centralised control paradigms if they provide high‐level usage statistics and control interfaces for supporting and deploying centralised policy decisions. We present a general method to compute target values for an arbitrary metric on the local system state and show that autonomous rebalancing actions based on the target values can be used to reliably and robustly improve the balance for metrics based on probabilistic risk estimates. To balance the trade‐off between balancing efficiency and cost, we introduce 2 methods of deriving rebalancing actuations from the computed targets that depend on parameters that directly affects the trade‐off. This enables policy level control of the distributed mechanism based on collected metric statistics from network elements. Evaluation results based on cellular radio access network simulations indicate that load balancing based on probabilistic overload risk metrics provides more robust balancing solutions with fewer handovers compared to a baseline setting based on average load.     

Biomaterials for ocular reconstruction

Synthetic materials have played a significant role in ophthalmic applications to improve vision for many years. This has been in four main areas in ophthalmology: ocular surface reconstruction, lens replacement, vitreous replacement and structural support and cell transplantation in the retina. Corneal replacement therapies have been developed using both synthetic acrylic-based materials and more recently naturally derived materials such as amniotic membrane. Intraocular lenses as a replacement for the natural lens post cataract surgery has been used for many years. Newer developments include the opportunity to use gels so that the lenses can accommodate but these need improving in terms of the cross-linking chemistry. Silicone oils have been used as long-term tamponade agents as vitreous replacements but recent developments in their properties has enhanced the clinical outcomes and further research into their use as drug delivery vehicles will be a major advancement. Regenerative medicine therapies to repopulate the retina to repair and replace specific cell layers require the optimisation of synthetic scaffolds and this is a major area for development. Recent developments in biomaterials have emphasised the importance of the physical, chemical and mechanical properties specific to a particular ophthalmic application. Materials science has a critical role in developing strategies to overcome vision loss.     

Cumulative Sum Control Charts for Monitoring Weibull‐distributed Time Between Events

The Weibull distribution can be used to effectively model many different failure mechanisms due to its inherent flexibility through the appropriate selection of a shape and a scale parameter. In this paper, we evaluate and compare the performance of three cumulative sum (CUSUM) control charts to monitor Weibull‐distributed time‐between‐event observations. The first two methods are the Weibull CUSUM chart and the exponential CUSUM (ECUSUM) chart. The latter is considered in literature to be robust to the assumption of the exponential distribution when observations have a Weibull distribution. For the third CUSUM chart included in this study, an adjustment in the design of the ECUSUM chart is used to account for the true underlying time‐between‐event distribution. This adjustment allows for the adjusted ECUSUM chart to be directly comparable to the Weibull CUSUM chart. By comparing the zero‐state average run length and average time to signal performance of the three charts, the ECUSUM chart is shown to be much less robust to departures from the exponential distribution than was previously claimed in the literature. We demonstrate the advantages of using one of the other two charts, which show surprisingly similar performance. Copyright © 2014 John Wiley & Sons, Ltd.