9,898 research outputs found
Investigation of Mechanical Properties of Cryogenically Treated Music Wire
It has been reported that treating music wire (high carbon steel wire) by
cooling to cryogenic temperatures can enhance its mechanical properties with
particular reference to those properties important for musical performance. We
use such wire for suspending many of the optics in Advanced LIGO, the upgrade
to LIGO - the Laser Interferometric Gravitational-Wave Observatory. Two
properties that particularly interest us are mechanical loss and breaking
strength. A decrease in mechanical loss would directly reduce the thermal noise
associated with the suspension, thus enhancing the noise performance of mirror
suspensions within the detector. An increase in strength could allow thinner
wire to be safely used, which would enhance the dilution factor of the
suspension, again leading to lower suspension thermal noise. In this article we
describe the results of an investigation into some of the mechanical properties
of music wire, comparing untreated wire with the same wire which has been
cryogenically treated. For the samples we studied we conclude that there is no
significant difference in the properties of interest for application in
gravitational wave detectors
How can a multimodal approach to primate communication help us understand the evolution of communication?
Scientists studying the communication of non-human animals are often aiming to better understand the evolution of human communication, including human language. Some scientists take a phylogenetic perspective, where the goal is to trace the evolutionary history of communicative traits, while others take a functional perspective, where the goal is to understand the selection pressures underpinning specific traits. Both perspectives are necessary to fully understand the evolution of communication, but it is important to understand how the two perspectives differ and what they can and cannot tell us. Here, we suggest that integrating phylogenetic and functional questions can be fruitful in better understanding the evolution of communication. We also suggest that adopting a multimodal approach to communication might help to integrate phylogenetic and functional questions, and provide an interesting avenue for research into language evolution
Which program for whom? Evidence on the comparative effectiveness of public sponsored training programs in Germany
We use a new and exceptionally rich administrative data set for Germany to evaluate the employment effects of a variety of public sponsored training programs in the early 2000s. Building on the work of Sianesi (2003, 2004), we employ propensity score matching methods in a dynamic, multiple treatment framework in order to address program heterogeneity and dynamic selection into programs. Our results suggest that in West Germany both short-term and medium-term programs show considerable employment effects for certain population subgroups but in some cases the effects are zero in the medium run. Short-term programs are surprisingly effective when compared to the traditional and more expensive longer-term programs. With a few exceptions, we find little evidence for significant positive treatment effects in East Germany. There is some evidence that the employment effects decline for older workers and for low-skilled workers
Exploring the acceptability of two self-sampling devices for human papillomavirus testing in the cervical screening context: a qualitative study of Muslim women in London
Objectives We explored Muslim women's attitudes to self-sampling for human papillomavirus (HPV) in the context of cervical cancer screening and their responses to two self-sampling devices.Setting A Muslim community centre in north-east London.Methods Following a talk given on the subject of cervical cancer and HPV at the community centre, 28 women were recruited to take part in three focus group discussions. The discussion covered cervical screening, self-sampling and HPV testing. Women were also asked for their responses to a swab self-sampling kit and a cervico-vaginal lavage device. Discussions were recorded and transcribed verbatim and the qualitative data were analysed using Framework Analysis.Results Participants were generally positive about cervical screening but acknowledged that some women in their community were reluctant to offend because of embarrassment, language difficulties, fear or because they were unmarried and did not want to communicate implicit messages about being sexually active. Self-sampling met a mixed response - women were concerned about not doing the test correctly, but thought that it might overcome barriers to screening for some women. HPV testing itself was thought to raise potentially difficult issues relating to trust and fidelity within marriages. Although most women said they would prefer to continue to have screening by a health professional, if they were to perform self-sampling, there was overwhelming preference for the swab over the lavage kit.Conclusions There was limited enthusiasm for self-sampling in this group of Muslim women who had mostly attended for cervical screening, but a clear preference for a swab rather than a cervico-vaginal lavage
THE PRICING EFFICIENCY OF AGRICULTURAL FUTURES MARKETS: AN ANALYSIS OF PREVIOUS RESEARCH RESULTS
The analysis examines quantitatively the findings of previous studies of the pricing efficiency of various agricultural markets using a logit framework. The findings provide insight into the importance of commodity characteristics, uncertainty, and testing procedures used on the results of past research of pricing efficiency. The study also identifies several areas for further research.Demand and Price Analysis,
Momentum Cogging at the Fermilab Booster
The Fermilab booster has an intensity upgrade plan called the Proton
Improvement plan (PIP). The flux throughput goal is 2E17 protons/hour which is
almost double the current operation at 1.1E17 protons/hour. The beam loss in
the machine is going to be an issue. The booster accelerates beam from 400 MeV
to 8GeV and extracts to The Main Injector (MI). Cogging is the process that
synchronizes the extraction kicker gap to the MI by changing radial position of
the beam during the cycle. The gap creation occurs at about 700MeV which is
6msec into the cycle. The variation of the revolution frequency from cycle to
cycle is larger at lower energy and it is hard to control by changing the
radial position because of aperture limitations. Momentum cogging is able to
move the gap creation earlier by using dipole correctors and radial position
feedback, and controlling the revolution frequency and radial position at the
same time. The new cogging is going to save energy loss and aperture. The
progress of the momentum cogging system development is going to be discussed in
this paper.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
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