Electrolyte management in porous battery components. Static measurements

The interaction between the porous hydrogen and nickel electrodes and microporous separator with respect to electrolyte management in nickel/hydrogen cells has been investigated. The distribution of electrolyte among the components has been measured and correlated with the pore size distributions, total void volume, and resistance of a variety of electrodes and separators. Calculations are used to show the effects of systematically varying these properties

Pore size engineering applied to the design of separators for nickel-hydrogen cells and batteries

Pore size engineering in starved alkaline multiplate cells involves adopting techniques to widen the volume tolerance of individual cells. Separators with appropriate pore size distributions and wettability characteristics (capillary pressure considerations) to have wider volume tolerances and an ability to resist dimensional changes in the electrodes were designed. The separators studied for potential use in nickel-hydrogen cells consist of polymeric membranes as well as inorganic microporous mats. In addition to standard measurements, the resistance and distribution of electrolyte as a function of total cell electrolyte content were determined. New composite separators consisting of fibers, particles and/or binders deposited on Zircar cloth were developed in order to engineer the proper capillary pressure characteristics in the separator. These asymmetric separators were prepared from a variety of fibers, particles and binders

X-ray Measurement of the subpixel structure of the XMM EPIC MOS CCD

We report here the results of a mesh experiment to measure the subpixel structure of the EPIC MOS CCDs on board the XMM X-ray observatory. The pixel size is 40$\mu$m square while the mesh hole spacing is 48$\mu$m, a combination quite different from our standard mesh experiment. We have verified that this combination functions properly and have analyzed the CCD structure with sub-pixel resolution. The EPIC MOS CCD has an open electrode structure to improve detection efficiency at low energies. We obtained the distribution of various grades of X-ray events inside the pixel. A horizontally split two-pixel event is generated near the channel stop which forms a straight vertical pixel boundary whereas a vertically split two-pixel event is generated where the potential due to the thinned gate structure forms a wavy horizontal pixel boundary. Therefore, the effective pixel shape is not a square but is distorted. The distribution of X-ray events clearly shows that the two etched regions in each pixel, separated by the bridging finger of the enlarged (open) electrode. We measured the difference in X-ray transmission between the conventional and open regions of the pixel using O-K and Cu-L X-ray emission lines, and found it to be consistent with an electrode thickness comprising $0.2\pm0.1\mu$m of Si and $0.6\pm0.2\mu$m of SiO2.Comment: 9 pages, 5 figures, accepted for publication in Nucl. Instr. and Methods

Low noise charge injection in the CCD22

The inclusion of a charge injection structure on a charge coupled device (CCD) allows for the mitigation of charge transfer loss which can be caused by radiation induced charge trapping defects. Any traps present in the pixels of the CCD are filled by the injected charge as it is swept through the device and consequently, the charge transfer efficiency is improved in subsequently acquired images. To date, a number of different types of CCD have been manufactured featuring a variety of charge injection techniques. The e2v Technologies CCD22, used in the EPIC MOS focal plane instruments of XMM-Newton, is one such device and is the subject of this paper. A detailed understanding of charge injection operation and the use of charge injection to mitigate charge transfer losses resulting from radiation damage to CCDs will benefit a number of space projects planned for the future, including the ESA GAIA and X-ray Evolving Universe Spectrometry (XEUS) missions.The charge injection structure and mode of operation of the CCD22 are presented, followed by a detailed analysis of the uniformity and repeatability of the charge injection amplitude across the columns of the device. The effects of proton irradiation on the charge injection characteristics are also presented, in particular the effect of radiation induced bright pixels on the injected charge level

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis.

ObjectiveResearch evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing.MethodPeer reviewed studies published from 1964-January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care.ResultsThe meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3-5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age.ConclusionsThis meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older

The seroprevalence and factors associated with Ross River virus infection in Western Grey Kangaroos (Macropus fuliginosus) in Western Australia

A serosurvey was undertaken in 15 locations in the midwest to southwest of Western Australia (WA) to investigate the seroprevalence of Ross River virus (RRV) neutralizing antibodies and factors associated with infection in western grey kangaroos (Macropus fuliginosus). The estimated seroprevalence in 2632 kangaroo samples, using a serum neutralization test, was 43.9% (95% CI 42.0, 45.8). Location was significantly associated with seroprevalence (p 0.05). The results of this study indicate that kangaroos in WA are regularly infected with RRV and may be involved in the maintenance and transmission of RRV

Rank-(n – 1) convexity and quasiconvexity for divergence free fields

The CAST experiment at CERN (European Organization of Nuclear Research) searches for axions from the sun. The axion is a pseudoscalar particle that was motivated by theory thirty years ago, with the intention to solve the strong CP problem. Together with the neutralino, the axion is one of the most promising dark matter candidates. The CAST experiment has been taking data during the last two years, setting an upper limit on the coupling of axions to photons more restrictive than from any other solar axion search in the mass range below 0.1 eV. In 2005 CAST will enter a new experimental phase extending the sensitivity of the experiment to higher axion masses. The CAST experiment strongly profits from technology developed for high energy physics and for X-ray astronomy: A superconducting prototype LHC magnet is used to convert potential axions to detectable X-rays in the 1-10 keV range via the inverse Primakoff effect. The most sensitive detector system of CAST is a spin-off from space technology, a Wolter I type X-ray optics in combination with a prototype pn-CCD developed for ESA's XMM-Newton mission. As in other rare event searches, background suppression and a thorough shielding concept is essential to improve the sensitivity of the experiment to the best possible. In this context CAST offers the opportunity to study the background of pn-CCDs and its long term behavior in a terrestrial environment with possible implications for future space applications. We will present a systematic study of the detector background of the pn-CCD of CAST based on the data acquired since 2002 including preliminary results of our background simulations.Comment: 11 pages, 8 figures, to appear in Proc. SPIE 5898, UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XI

Moving from a Product-Based Economy to a Service-Based Economy for a More Sustainable Future

Traditionally, economic growth and prosperity have been linked with the availability, production and distribution of tangible goods as well as the ability of consumers to acquire such goods. Early evidence regarding this connection dates back to Adam Smith's Wealth of Nations (1776), in which any activity not resulting in the production of a tangible good is characterized as unproductive of any value." Since then, this coupling of economic value and material production has been prevalent in both developed and developing economies throughout the world. One unintended consequence of this coupling has been the exponential increase in the amount of solid waste being generated. The reason is that any production and consumption of material goods eventually generates the equivalent amount of (or even more) waste. Exacerbating this problem is the fact that, with today's manufacturing and supply chain management technologies, it has become cheaper to dispose and replace most products rather than to repair and reuse them. This has given rise to what some call a disposable society." To put things in perspective: In 2012 households in the U.K. generated approximately 22 thousand tons of waste, which amounted to 411 kg of waste generated per person (Department for Environment, Food & Rural Affairs, 2015). During the same time period, households in the U.S. generated 251 million tons of waste, which is equivalent to a person generating approximately 2 kg of waste every day (U.S. Environmental Protection Agency, 2012). Out of these 251 million tons of total waste generated, approximately 20% of the discarded items were categorized as durable goods. The disposal of durable goods is particularly worrisome because they are typically produced using material from non- renewable resources such as iron, minerals, and petroleum-based raw materials