Impulse gage development for the 100-200 ktap range

Special effects underground test (UGT) material response and source diagnostics data require impulse gages that can be used in the 50--150 ktap range and have equilibrated from electrical and mechanical noise sources within 0.001 s. Such gages were designed, analyzed, and tested under this program. One- and two-dimensional stress propagation calculations were performed and predictions were developed for deformation of the gage specimen cup. These predictions were conservative when compared to gas gun test results. The response of the gage will equilibrate within 5% to its final value within 300 {mu}sec. The impulse delivered to the gages for these tests exceeded 250 ktap. The code and experimental results provides a basis for confidence in the operability of the gage in an actual UGT environment

The verdict geometric quality library.

Verdict is a collection of subroutines for evaluating the geometric qualities of triangles, quadrilaterals, tetrahedra, and hexahedra using a variety of metrics. A metric is a real number assigned to one of these shapes depending on its particular vertex coordinates. These metrics are used to evaluate the input to finite element, finite volume, boundary element, and other types of solvers that approximate the solution to partial differential equations defined over regions of space. The geometric qualities of these regions is usually strongly tied to the accuracy these solvers are able to obtain in their approximations. The subroutines are written in C++ and have a simple C interface. Each metric may be evaluated individually or in combination. When multiple metrics are evaluated at once, they share common calculations to lower the cost of the evaluation

A numerical scheme for modelling reacting flow with detailed chemistry and transport.

An efficient projection scheme is developed for the simulation of reacting flow with detailed kinetics and transport. The scheme is based on a zero-Mach-number formulation of the compressible conservation equations for an ideal gas mixture. It is a modified version of the stiff operator-split scheme developed by Knio, Najm & Wyckoff (1999, J. Comput. Phys. 154, 428). Similar to its predecessor, the new scheme relies on Strang splitting of the discrete evolution equations, where diffusion is integrated in two half steps that are symmetrically distributed around a single stiff step for the reaction source terms. The diffusive half-step is integrated using an explicit single-step, multistage, Runge-Kutta-Chebyshev (RKC) method, which replaces the explicit, multi-step, fractional sub-step approach used in the previous formulation. This modification maintains the overall second-order convergence properties of the scheme and enhances the efficiency of the computations by taking advantage of the extended real-stability region of the RKC scheme. Two additional efficiency-enhancements are also explored, based on an extrapolation procedure for the transport coefficients and on the use of approximate Jacobian data evaluated on a coarse mesh. By including these enhancement schemes, performance tests using 2D computations with a detailed C{sub 1}C{sub 2} methane-air mechanism and a detailed mixture-averaged transport model indicate that speedup factors of about 15 are achieved over the previous split-stiff scheme

Low-Cost, Fiber-Optic Hydrogen Gas Detector Using Guided-Wave, Surface-Plasmon Resonance in Chemochromic Thin Films

Low-cost, hydrogen-gas-leak detectors are needed for many hydrogen applications, such as hydrogen-fueled vehicles where several detectors may be required in different locations on each vehicle. A fiber-optic leak detector could be inherently safer than conventional detectors, because it would remove all detector electronics from the vicinity of potential leaks. It would also provide freedom from electromagnetic interference, a serious problem in fuel-cell-powered electric vehicles. This paper describes the design of a fiber-optic, surface-plasmon-resonance hydrogen detector, and efforts to make it more sensitive, selective, and durable. Chemochromic materials, such as tungsten oxide and certain Lanthanide hydrides, can reversibly react with hydrogen in air while exhibiting significant changes in their optical properties. Thin films of these materials applied to a sensor at the end of an optical fiber have been used to detect low concentrations of hydrogen gas in air. The coatings include a thin silver layer in which the surface plasmon is generated, a thin film of the chemochromic material, and a catalytic layer of palladium that facilitates the reaction with hydrogen. The film thickness is chosen to produce a guided-surface plasmon wave along the interface between the silver and the chemochromic material. A dichroic beam-splitter separates the reflected spectrum into a portion near the resonance and a portion away from the resonance, and directs these two portions to two separate photodiodes. The electronic ratio of these two signals cancels most of the fiber transmission noise and provides a stable hydrogen signal

COTS software selection process.

Today's need for rapid software development has generated a great interest in employing Commercial-Off-The-Shelf (COTS) software products as a way of managing cost, developing time, and effort. With an abundance of COTS software packages to choose from, the problem now is how to systematically evaluate, rank, and select a COTS product that best meets the software project requirements and at the same time can leverage off the current corporate information technology architectural environment. This paper describes a systematic process for decision support in evaluating and ranking COTS software. Performed right after the requirements analysis, this process provides the evaluators with more concise, structural, and step-by-step activities for determining the best COTS software product with manageable risk. In addition, the process is presented in phases that are flexible to allow for customization or tailoring to meet various projects' requirements

A prospective, double-blind, randomized, controlled clinical trial comparing standard wound care with adjunctive hyperbaric oxygen therapy (HBOT) to standard wound care only for the treatment of chronic, non-healing ulcers of the lower limb in patients with diabetes mellitus: a study protocol

<p>Abstract</p> <p>Background</p> <p>It has been suggested that the use of adjunctive hyperbaric oxygen therapy improves the healing of diabetic foot ulcers, and decreases the risk of lower extremity amputations. A limited number of studies have used a double blind approach to evaluate the efficacy of hyperbaric oxygen therapy in the treatment of diabetic ulcers. The primary aim of this study is to assess the efficacy of hyperbaric oxygen therapy plus standard wound care compared with standard wound care alone in preventing the need for major amputation in patients with diabetes mellitus and chronic ulcers of the lower limb.</p> <p>Methods/Design</p> <p>One hundred and eighteen (59 patients per arm) patients with non-healing diabetic ulcers of the lower limb, referred to the Judy Dan Research and Treatment Centre are being recruited if they are at least 18 years of age, have either Type 1 or 2 diabetes with a Wagner grading of foot lesions 2, 3 or 4 on lower limb not healing for at least 4 weeks. Patients receive hyperbaric oxygen therapy every day for 6 weeks during the treatment phase and are provided ongoing wound care and weekly assessments. Patients are required to return to the study centre every week for an additional 6 weeks of follow-up for wound evaluation and management. The primary outcome is freedom from having, or meeting the criteria for, a major amputation (below knee amputation, or metatarsal level) up to 12 weeks after randomization. The decision to amputate is made by a vascular surgeon. Other outcomes include wound healing, effectiveness, safety, healthcare resource utilization, quality of life, and cost-effectiveness. The study will run for a total of about 3 years.</p> <p>Discussion</p> <p>The results of this study will provide detailed information on the efficacy of hyperbaric oxygen therapy for the treatment of non-healing ulcers of the lower limb. This will be the first double-blind randomized controlled trial for this health technology which evaluates the efficacy of hyperbaric oxygen therapy in prevention of amputations in diabetic patients.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00621608">NCT00621608</a></p

Electronic and photonic power applications

Efficient conversion of radioactive decay to electrical power has been the goal of a number of past research efforts. One of these was the Elgin-Kidde nuclear battery. In this concept promethium-147 was used as a beta source which was then mixed with a phosphor to produce a radioluminescent (RL) source of light. The light source was coupled to silicon photovoltaic converters to create electricity. This photoelectric approach is being revisited using tritium based solid state compounds and advanced gas concepts to produce RL light sources being disclosed at this conference. Efficient conversion of the RL light energy to electrical energy imposes certain requirements on the semiconductor converter. These requirements will be discussed. Projections of power source electrical and physical characteristics will be presented based on reasonable design parameter assumptions. The words Power Supply'' usually evoke a vision of a rotating machine or chemical battery. However, today's technology is making increasing use of photonics, where information and even power can be moved through optical fibers. Brighter volumetric RL light sources open a whole new range of photonics-based applications, while solid state tritiated compounds provide the foundation for improved mechanical adaptability and safety. 4 refs., 6 figs., 1 tab

Statistical process control of mortality series in the Australian and New Zealand Intensive Care Society (ANZICS) adult patient database: implications of the data generating process

for the ANZICS Centre for Outcome and Resource Evaluation (CORE) of the Australian and New Zealand Intensive Care Society (ANZICS)BACKGROUND Statistical process control (SPC), an industrial sphere initiative, has recently been applied in health care and public health surveillance. SPC methods assume independent observations and process autocorrelation has been associated with increase in false alarm frequency. METHODS Monthly mean raw mortality (at hospital discharge) time series, 1995–2009, at the individual Intensive Care unit (ICU) level, were generated from the Australia and New Zealand Intensive Care Society adult patient database. Evidence for series (i) autocorrelation and seasonality was demonstrated using (partial)-autocorrelation ((P)ACF) function displays and classical series decomposition and (ii) “in-control” status was sought using risk-adjusted (RA) exponentially weighted moving average (EWMA) control limits (3 sigma). Risk adjustment was achieved using a random coefficient (intercept as ICU site and slope as APACHE III score) logistic regression model, generating an expected mortality series. Application of time-series to an exemplar complete ICU series (1995-(end)2009) was via Box-Jenkins methodology: autoregressive moving average (ARMA) and (G)ARCH ((Generalised) Autoregressive Conditional Heteroscedasticity) models, the latter addressing volatility of the series variance. RESULTS The overall data set, 1995-2009, consisted of 491324 records from 137 ICU sites; average raw mortality was 14.07%; average(SD) raw and expected mortalities ranged from 0.012(0.113) and 0.013(0.045) to 0.296(0.457) and 0.278(0.247) respectively. For the raw mortality series: 71 sites had continuous data for assessment up to or beyond lag ₄₀ and 35% had autocorrelation through to lag ₄₀; and of 36 sites with continuous data for ≥ 72 months, all demonstrated marked seasonality. Similar numbers and percentages were seen with the expected series. Out-of-control signalling was evident for the raw mortality series with respect to RA-EWMA control limits; a seasonal ARMA model, with GARCH effects, displayed white-noise residuals which were in-control with respect to EWMA control limits and one-step prediction error limits (3SE). The expected series was modelled with a multiplicative seasonal autoregressive model. CONCLUSIONS The data generating process of monthly raw mortality series at the ICU level displayed autocorrelation, seasonality and volatility. False-positive signalling of the raw mortality series was evident with respect to RA-EWMA control limits. A time series approach using residual control charts resolved these issues.John L Moran, Patricia J Solomo

Hypotheses on L-H transition

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman