6,562 research outputs found
J.P. Slack "The Military Career of Sam Houston" Book Review
No full textBook review done by Sam Houston Normal Institute student, J.P. Slack, on "Life of Sam Houston" by C. Edwards Leste
Gas sensors using correlation spectroscopy compatible with fibre-optic operation
No full textThis paper reviews methods for gas detection using real-time correlation spectroscopy. These methods involve using a gas sample in a reference cell as a matched optical filter to detect, preferentially, similar absorption spectra in a measurement cell. The methods all have the advantage of excellent selectivity, even using broadband sources, and are suitable for remote detection over optical-fibre leads. Our previously published methods using pressure and Stark modulation are reviewed. In addition, our recent theoretical treatment of the methods is presented. Finally, we describe new atmospheric-pressure measurements of gases using the method of phase-modulation spectroscopy
A novel optical fibre gas sensor employing pressure-modulation spectroscopy
No full textAn optical fibre gas sensor using a pressure-modulation resonant-acoustic reference cell is employed to pressure modulate technique is demonstrated. A the absorption of a gas in the near infra-red. The system exhibits good selectivity, low response to contaminant gases, and a noise-limited sensitivity equivalent to 50ppm by volume for methane sensing
Correlation spectroscopy gas sensors compatible with fibre-optic remoted operation
No full textThe paper reports three basic methods of gas sensing using real-time correlation spectroscopy. In each method, a sample of the gas to be measured is used as a matched optical filter in order to recognise similar features in the absorption spectrum of gas in the measurement cell
Progress in fibre-remoted gas correlation spectrometry
No full textThe paper reports on the progress in gas sensing using real-time correlation spectroscopy, where a gas is used as a matched optical filter to recognize its own spectral absorption lines. The basic concept of correlation spectrometry involves the passage of light sequentially through two gas cells: a reference cell containing a known quantity of the gas to be detected. and a sampling cell where the presence of the gas is to be determined. An optical signal passing through both cells will suffer absorption due to the gas in each. If the absorption in the reference Cell is periodically modulated, then the total absorption depends on whether the gas absorption lines in the sampling cell correlate with those in the reference cell gas. Two methods of modulating the reference cell absorption are reported, pressure and Stark modulation. Results are presented for methane detection employing pressure modulation. The pressure fluctuations are generated within a compact resonant acoustic cell driven by a piezoelectric transducer. Also given are results for cross-sensitivity measurements with ethane as the contaminant gas. The Stark technique is applied to ammonia detection here, but can be used with many gases that exhibit a strong dipole moment
Review of the people make the place: dynamic linkages between individuals and organizations
No full textReview of D. Brent Smith ( Editor ). The People Make the Place: Dynamic Linkages Between Individuals and Organizations . New York : Lawrence Erlbaum Associates , 2008 , 316 pages, $79.95 hardcover .Reviewed by Jon Billsberry, Coventry University, Danielle L. Talbot, Patrick C. Nelson, Julian A. Edwards, Steven G. Godrich, Ross A.G. Davidson, and Christopher J.P. Carter, The Open University
Histone deacetylase inhibitors and their potential role in inflammatory bowel diseases
No full textIBDs (inflammatory bowel diseases) are lifelong manifestations that significantly impair the quality of life of those who suffer from them. Although many therapies are now available, including immunomodulatory drugs such as Infliximab which have efficacy in IBD, not all patients respond and some patients generate autoantibodies against these drugs. Hence the search for novel treatments is ongoing. HDACs (histone deacetylases) are responsible for condensation of chromatin in the nucleus of cells and inhibition of gene transcription and are often dysregulated during cancer. HDAC inhibitors allow normal gene transcription to be restored and provide attractive therapeutic options, as they have been shown to be anti-inflammatory and anti-proliferative in cancer. Indeed, two HDAC inhibitors have been recently approved for the treatment of cutaneous T-cell lymphoma in the U.S.A. Recent research using animal models has shown that HDAC inhibitors may have a beneficial effect in colitis by boosting levels of Foxp3+ (forkhead box P3+) T-regulatory cells that dampen inflammation. In the present paper, we outline the background to IBD, HDACs and their inhibitors as well as discussing their current use in models of IBD
Progress with optical gas sensors using correlation spectroscopy
No full textThe paper reviews recent progress on gas detection using real-time correlation spectroscopy. The general method relies on using a gas sample in a reference cell as a matched optical filter, to preferentially detect similar absorption spectra in a measurement cell. All variations of the method have the advantage of excellent selectivity for gases with narrow line spectra, even when using broadband sources for illumination. They are also suitable for remote detection over optical fibre leads. The recent progress is in two main areas. Firstly, the earlier reported Stark modulation method has been extended to investigate a novel hygrometer. Secondly, we have developed a novel multi-line light source, by combining a broadband optical source with a Michelson interferometer, where the latter contains a gas in one arm
Voice Compression and Communications: Principles and Applications for Fixes and Wireless Channels
No full textUp-to-date, expert coverage of topics in wireless voice communications Voice communication is the most important facet of mobile radio service. Even when the predicted surge of wireless data and Internet services becomes a reality, voice will remain the most natural means of human communication. Voice Compression and Communications details issues in wireless voice communications and treats compression, channel coding, and wireless transmission as a joint subject. Part I covers background material, whereas Part II provides detailed information on both proprietary and standardized analysis-by-synthesis codecs, including the speech codecs of virtually all existing wireline-based and wireless systems. Parts III and IV discuss mainly research-based wideband, audio, as well as very low-rate schemes likely to find their way into future standards. Voice Compression and Communications describes fundamental concepts in a non-mathematical way early in the book for those with only a background knowledge of signal processing and communications. More advanced readers will find detailed discussions of theoretical principles, future concepts, and solutions to various specific wireless voice communications problems
Broadband sources for gas detection using fluorescent rare-earth-doped fibres pumped by low-cost semiconductor laser source
No full textThe paper discusses recent results on sources for gas detection using fluorescent rare-earth-doped optical fibres. The sources are being optimised for use with broadband cognitive gas sensors, in particular those using correlation spectroscopy, with the constraint of using low-cost semiconductor lasers as the pump
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