UK PubMed Central (United Kingdom)

The likelihood that past experience will produce correct guides to current practice depends on the signal-to-noise ratio for the clinical problem of interest. If the signal-to-noise ratio is high, the...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Snapping or grating scapula is a condition of the shoulder girdle in which the patient complains of pain and an audible snapping sound which may be associated with pain. We evaluated the diagnostic value of the computed tomography (CT) scans using the clinical diagnosis of a grating scapula as the gold standard. This retrospective study reports the sensitivity, specificity, likelihood ratio and receiver operator characteristic curve for the CT scans and the k value as a measure of the interobserver agreement. None of the parameters validated the examination. We therefore concluded that CT scans are inappropriate for differentiation between a grating scapula and a normally functioning shoulder except in cases where bony abnormalities are present. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Various statistical methods for the estimation of the mean lifetimes of charmed particles have been considered. It is shown that the usual estimates of the maximum likelihood in some cases do not exist or may have rather great positive bias, if the statistics are low. Alternative estimates of the mean lifetime tau are discussed. Among them the 'jackknife' estimate of tau is considered. The minimum variance unbiased estimates of the average rate of decay 1/tau have been derived for some particular cases. It is also shown that the usual estimate of the ratio of the mean lifetimes of different kinds of particles may also have a bias when the statistics are poor. Two methods of reducing this bias have been proposed.

Energy Technology Data Exchange (ETDEWEB)

Various statistical methods for the estimation of the mean lifetimes of charmed particles have been considered. It is shown that the usual estimates of the maximum likelihood in some cases do not exist or may have rather great positive bias, if the statistics are low. Alternative estimates of the mean lifetime tau are discussed. Among them the 'jackknife' estimate of tau is considered. The minimum variance unbiased estimates of the average rate of decay 1/tau have been derived for some particular cases. It is also shown that the usual estimate of the ratio of the mean lifetimes of different kinds of particles may alos have a bias when the statistics are poor. Two methods of reducing this bias have been proposed. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Estimation of mixed Weibull distribution by maximum likelihood estimation and other methods is frequently difficult due to unstable estimates arising from limited data. Bayesian techniques can stabilize these estimates through the priors, but there is no closed-form conjugate family for the Weibull distribution. This paper reduces the number of numeric integrations required for using Bayesian estimation on mixed Weibull situations from five to two, thus making it a more feasible approach to the typical user. It also examines the robustness of the Bayesian estimates under a variety of different prior distributions. It is found that Bayesian estimation can improve accuracy over the MLE for situations with low mixture ratios so long as the prior on the weak subpopulation's characteristic life has an expected value less than or equal to the true characteristic life.

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... (restricted)] 256-264 Influence of likelihood function choice for estimating crop model parameters using the generalized likelihood uncertainty estimation method by He, Jianqiang & Jones, James W. & Graham, Wendy D. & Dukes, Michael D. [Downloadable! (restricted)]...

CERN Document Server

Learning to love the errror matrix lecture : Learning to love the errror matrix Introductory remarks. Conditional probability. Statistical and systematic errors. Combining results Binomial, Poisson and 1-D Gaussian 2-D Gaussian and the error matrix. Understanding the covariance. Using the error matrix. Estimating the error matrix. Combining correlated measurements Parameter determination by likelihood Do's and don'ts lecture : Parameter determination by likelihood : Do's and don'ts Introduction to likelihood. Error estimate. Simple examples: (1) Breit Wigner (2) Lifetime Binned and unbinned likelihood Several parameters Extended maximum likelihood. Common misapprehensions: Normalisation delta(lnL) = 1/2 rule and coverage Integrating the likelihood Unbinned L_max as goodness of fit Punzi effect Chi-squared and hypothesis testing lecture : Chi-squared and ...

Science.gov (United States)

Removal Sampling is an easy-to-use Windows program which calculates population statistics from removal trapping experiment data. Using maximum likelihood methods it ... ...

Science.gov (United States)

We adapt the Jain-Taylor (2003) shear-ratio geometric lensing method to measure the dark energy equation of state, w = pv/?v and its time derivative from dark matter haloes in cosmologies with arbitrary spatial curvature. The full shear-ratio covariance matrix is calculated for lensed sources, including the intervening large-scale structure and photometric redshift errors as additional sources of noise, and a maximum likelihood method for applying the test is presented. Decomposing the lensing matter distribution into dark matter haloes we calculate the parameter covariance matrix for an arbitrary experiment. Combining with the expected results from the cosmic microwave background (CMB) we design an optimal survey for probing dark energy. This shows that a targeted survey imaging 60 of the largest clusters in a hemisphere with five-band optical photometric redshifts to a median galaxy depth of zm = 0.9 could measure w0 ? ...

CERN Document Server

RooStats is a project to create advanced statistical tools required for the analysis of LHC data, with emphasis on discoveries, confidence intervals, and combined measurements. The idea is to provide the major statistical techniques as a set of C++ classes with coherent interfaces, which can be used on arbitrary model and datasets in a common way. The classes are built on top of RooFit, which provides a very convenient functionality for modeling the probability density functions or the likelihood functions, required as inputs for any statistical technique. Furthermore, RooFit provides the functionality for easily creating models, for analysis combination and for digital publication of the likelihood function and the data. We will present in detail the design and the implementation of the different statistical methods of RooStats. These include various classes for interval estimation and for hypothesis test depending on different statistical ...

UK PubMed Central (United Kingdom)

We present several new results on the classic problem of estimating Gaussian profile parameters from a set of noisy data, showing that an exact solution of the maximum likelihood equations exists...Full Text Available

CERN Document Server

Convexity/concavity properties of symbol error rates (SER) of the maximum likelihood detector operating in the AWGN channel (non-fading and fading) are studied. Generic conditions are identified under which the SER is a convex/concave function of the SNR. Universal bounds for the SER 1st and 2nd derivatives are obtained, which hold for arbitrary constellations and are tight for some of them. Applications of the results are discussed, which include optimum power allocation in spatial multiplexing systems, optimum power/time sharing to decrease or increase (jamming problem) error rate, and implication for fading channels.

Energy Technology Data Exchange (ETDEWEB)

This probabilistic analysis of WIPP TRUDOCK crane failure is based on two sources of failure data. The source for operator errors is the report by Swain and Guttman, NUREG/CR-1278-F, August 1983. The source for crane cable hook breaks was initially made by WIPP/WID-96- 2196, Rev. O by using relatively old (1970s) U.S. Navy data (NUREG-0612). However, a helpful analysis by R.K. Deremer of PLG guided the authors to values that were more realistic and more conservative, with the recommendation that the crane cable/hook failure rate should be 2.5 x 10-6 per demand. This value was adopted and used. Based on these choices a mean failure rate of 9.70 x 10-3(1/yr) was calculated. However, a mean rate by itself does not reveal the level of confidence to be associated with this number. Guidance to making confidence calculations came from the report by Swain and Guttman, who stated that failure data could be described by lognormal distributions. This is in agreement with the widely use d reports ...

British Library Electronic Table of Contents (United Kingdom)

The extent of exchange rate pass-through has been playing an increasingly pivotal role in the transmission of exchange rate shocks and adequate policy responses. We develop a model of exchange rate pass-through that allows the stochastic process of exchange rate to include the lagged values of the velocity of money. We show that the likelihood and extent of pass-through is sensitive to the lagged response.

International Nuclear Information System (INIS)

A comparison of maximum likelihood (or chi-square) and Bayesian peak fitting techniques shows that the latter can reduce peak intensity uncertainties by a factor of up to ten in the case of closely separated doublets, leading to greatly improved doublet resolution. The need for laboratories to demonstrate the reliability of their chosen peak fitting techniques and measures of peak intensity is also demonstrated. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Abstract This paper proposes and analyses the autoregressive conditional root (ACR) time-series model. This multivariate dynamic mixture autoregression allows for non-stationary epochs. It proves to be an appealing alternative to existing nonlinear models, e.g. the threshold autoregressive or Markov switching class of models, which are commonly used to describe nonlinear dynamics as implied by arbitrage in presence of transaction costs. Simple conditions on the parameters of the ACR process and its innovations are shown to imply geometric ergodicity, stationarity and existence of moments. Furthermore, consistency and asymptotic normality of the maximum likelihood estimators are established. An application to real exchange rate data illustrates the analysis.

CERN Document Server

Stochastic Kronecker graphs supply a parsimonious model for large sparse real world graphs. They can specify the distribution of a large random graph using only three or four parameters. Those parameters have however proved difficult to choose in specific applications. This article looks at method of moments estimators that are computationally much simpler than maximum likelihood. The estimators are fast and in our examples, they typically yield Kronecker parameters with expected feature counts closer to a given graph than we get from KronFit. The improvement was especially prominent for the number of triangles in the graph.

British Library Electronic Table of Contents (United Kingdom)

Program decisions by symphony orchestra management are influenced by various factors. To examine these factors, we create an objective index of the propensity of a symphony orchestra to perform the standard repertoire. We use regression analysis to examine factors that influence programming decisions of 64 US symphony orchestras in 2006?2007, including public and private sources of funding. We find that increased funding from ticket sales, endowments, and local government increases the likelihood that an orchestra will perform nonstandard repertoire. In addition, the results suggest that a symphony orchestra?s music director does not have a significant impact on the degree of program conventionality.

British Library Electronic Table of Contents (United Kingdom)

Often, lifetime data come from experiments where failure times are grouped. The Weibull distribution is a popular distribution for modeling failure times. Maximum likelihood estimation (MLE) has outstanding large sample properties for the Weibull distribution. This article evaluates small sample properties of MLEs for grouped data. We evaluate sample size requirements for MLE asymptotic properties to take effect. We compare type I and type II censoring for pooled experiments and conclude that bias for the shape parameter estimate can be alarmingly high especially for type II censored data. Finally, we investigate the benefits of the pooled analysis.

International Nuclear Information System (INIS)

Radionuclide X-ray fluorescence analysis was used for the determination of Sr/Ca ratio in bones to test the influence of a diet on this ratio. Significant differences were observed for Sr/Ca ratio in bones of various animals. Only small differences in the Ca/Sr ratio were observed for the samples of various prehistoric human bones. (author) 4 refs.; 4 tabs.

Science.gov (United States)

It is important for the trauma surgeon to understand the basic principles of terminal gunshot ballistics and the study of the projectile's effect on striking soft tissue. The amount of kinetic energy dissipated to the tissue is directly related to the mass and velocity of the projectile as follows: K = MV2/2. Doubling the velocity quadruples the energy, while doubling the mass only doubles the energy. A temporary tissue cavity is produced as the striking projectile compresses the surrounding tissue; the higher the energy release, the more extensive the inapparent compressive damage. The permanent cavity that remains is the result of extrusion of tissue from the pathway of the projectile. The higher the velocity, the higher the likelihood of extensive damage. If the missile expands or fragments within the tissues, more damage will occur. PMID:6847483

British Library Electronic Table of Contents (United Kingdom)

Two studies (N = 420) were conducted to develop and validate the instructional dissent scale (IDS) for use in the college classroom. Participants in study 1 were 210 students who completed the IDS pilot inventory which was subjected to an exploratory factor analysis yielding three distinct factors of dissent (i.e., expressive, rhetorical, vengeful). Concurrent validity support was provided as perceived teacher misbehaviors were associated positively with students' likelihood of engaging in dissent and students reported fewer learning outcomes when they dissented. Participants in study 2 were from a different sample of 210 students who completed the IDS along with measures of classroom justice and student challenge behavior. A confirmatory factor analysis provided support for the hypothesiz...

British Library Electronic Table of Contents (United Kingdom)

In this paper we present the results of time series analysis for a coal mining region based on partial unmixing. We test the method also known as mixture tuned matched filtering on an eight image Landsat 5 TM and Landsat 7 ETM+ time series covering the period from 1987 to 2003. Common change detection methods often include the comparison of two interactively generated classification results, such as derived from Maximum Likelihood classification. These approaches often yield highly accurate results. However, disadvantages include a strong analyst bias and hardly repeatable results. For a quantitative monitoring of a single surface class' development over time they are often not recommendable. Our goal was to test an unbiased quantitative way to assess the development of coal surfaces, such...

British Library Electronic Table of Contents (United Kingdom)

Abstract In this paper we propose a smooth transition tree model for both the conditional mean and variance of the short-term interest rate process. The estimation of such models is addressed and the asymptotic properties of the quasi-maximum likelihood estimator are derived. Model specification is also discussed. When the model is applied to the US short-term interest rate we find: (1) leading indicators for inflation and real activity are the most relevant predictors in characterizing the multiple regimes' structure; (2) the optimal model has three limiting regimes. Moreover, we provide empirical evidence of the power of the model in forecasting the first two conditional moments when it is used in connection with bootstrap aggregation (bagging). Copyright 2010 John Wiley & Sons, Ltd.

DEFF Research Database (Denmark)

A food supplement containing fish oils, urtica dioica, zinc, and vitamin E (Phytalgic) for osteoarthritis (OA) has now been tested in a placebo-controlled trial for 3 months and according to the authors has a very large clinical effect, considerably larger than that of any other known product. Even experts endorsing nutraceuticals for OA symptoms would probably agree that a nutraceutical with an effect size above 0.5 is rarely seen. Despite our concerns about the fact that trial registration took place after the study was completed and the likelihood that patients would note the taste of fish, a circumstance that would lead to detection bias, we consider these data promising though with a high risk of bias.

Energy Technology Data Exchange (ETDEWEB)

This Safety Analysis Report (SAR) is prepared in compliance with the requirements of DOE Order 5480.23, Nuclear Safety Analysis Reports, and has been written to the format and content guide of DOE-STD-3009-94 Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Safety Analysis Reports. The Hot Cell Facility is a Hazard Category 2 nonreactor nuclear facility, and is operated by Sandia National Laboratories for the Department of Energy. This SAR provides a description of the HCF and its operations, an assessment of the hazards and potential accidents which may occur in the facility. The potential consequences and likelihood of these accidents are analyzed and described. Using the process and criteria described in DOE-STD-3009-94, safety-related structures, systems and components are identified, and the important safety functions of each SSC are described. Additionally, information which describes the safety management programs at SNL are described in ...

DEFF Research Database (Denmark)

The determination of conformational preferences in unfolded and disordered proteins is an important challenge in structural biology. We here describe an algorithm to optimize energy functions for the simulation of unfolded proteins. The procedure is based on the maximum likelihood principle and employs a fast and efficient gradient descent method to find the set of parameters of the energy function that best explain the experimental data. We first validate the method by using synthetic reference data, and subsequently apply the algorithms to data from nuclear magnetic resonance spin-labeling experiments on the Delta 131 Delta fragment of Staphylococcal nuclease. A significant strength of the procedure that we present is that it directly uses experimental data to optimize the energy parameters, without relying on the availability of high resolution structures. The procedure is fully general and can be applied to a range of experimental data and energy functions ...

CERN Document Server

Obtaining the set of cosmological parameters consistent with observational data is an important exercise in current cosmological research. It involves finding the global maximum of the likelihood function in the multi-dimensional parameter space. Currently sampling based methods, which are in general stochastic in nature, like Markov-Chain Monte Carlo(MCMC), are being commonly used for parameter estimation. The beauty of stochastic methods is that the computational cost grows, at the most, linearly in place of exponentially (as in grid based approaches) with the dimensionality of the search space. MCMC methods sample the full joint probability distribution (posterior) from which one and two dimensional probability distributions, best fit (average) values of parameters and then error bars can be computed. In the present work we demonstrate the application of another stochastic method, named Particle Swarm Optimization (PSO), that is widely used in the field of ...

British Library Electronic Table of Contents (United Kingdom)

The number of spent fuel storage facilities in the world continues to increase because of "Wait and See" policies and delay of a permanent disposal plan. The temporary spent fuel storage concept is changing to a pre-disposal storage concept. Strengthened safety concepts are required for expanded spent fuel storage facilities and sites. The Korea Hydro and Nuclear Power Company is planning to construct a reinforced concrete MACSTOR-400 facility at Wolsung. In concrete dry spent fuel storage structures, cracks can occur due to radiant heat and environmental chloride. The likelihood of cracking increases over time. Research on changes in shielding performance from one collinear crack in the surface of a concrete facility has been carried out. However there is no research about public radiolog...

British Library Electronic Table of Contents (United Kingdom)

In the parametric regression model, the covariate missing problem under missing at random is considered. It is often desirable to use flexible parametric or semiparametric models for the covariate distribution, which can reduce a potential misspecification problem. Recently, a completely nonparametric approach was developed by [H.Y. Chen, Nonparametric and semiparametric models for missing covariates in parameter regression, J. Amer. Statist. Assoc. 99 (2004), pp. 1176-1189; Z. Zhang and H.E. Rockette, On maximum likelihood estimation in parametric regression with missing covariates, J. Statist. Plann. Inference 47 (2005), pp. 206-223]. Although it does not require a model for the covariate distribution or the missing data mechanism, the proposed method assumes that the covariate distribut...

Science.gov (United States)

No Abstract Available

Energy Technology Data Exchange (ETDEWEB)

In radiation therapy with hadron beams, conformal irradiation to a tumour can be achieved by using the properties of incident ions such as the high dose concentration around the Bragg peak. For the effective utilization of such properties, it is necessary to evaluate the volume irradiated with hadron beams and the deposited dose distribution in a patient's body. Several methods have been proposed for this purpose, one of which uses the positron emitters generated through fragmentation reactions between incident ions and target nuclei. In the previous paper, we showed that the maximum likelihood estimation (MLE) method could be applicable to the estimation of beam end-point from the measured positron emitting activity distribution for mono-energetic beam irradiations. In a practical treatment, a spread-out Bragg peak (SOBP) beam is used to achieve a uniform biological dose distribution in the whole target volume. Therefore, in the present paper, we proposed ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

... slenderness ratio. Equations which determine the ultimate compressive strength of a composite were established. Several ...

KoreaScience (Korea)

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KoreaScience (Korea)

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Science.gov (United States)

The paper investigates the effect of the wall heat flux ratio on the local heat transfer augmentation in a square channel with two opposite in-line ribbed walls for Reynolds numbers from 15,000 to 80,000. The square channel composed of 10 isolated copper sections has a length-to-hydraulic diameter ratio of 20. The rib height-to-hydraulic diameter ratio is 0.0625 and the rib pitch-to-height ratio equals 10. Six ribbed side to smooth side wall heat flux ratios are studied for four rib orientations. The results show that the ribbed side wall heat transfer augmentation increases with increasing ribbed side to smooth side wall heat flux ratios, but the reverse is true for the smooth side wall heat transfer augmentation. The average heat transfer augmentation of the ribbed side and smooth side wall decreases slightly with increasing wall heat flux ...

CERN Document Server

We present an alternative, Bayesian method for large-scale reconstruction from observed peculiar velocity data. The method stresses a rigorous treatment of the random errors and it allows extrapolation into poorly sampled regions in real space or in k-space. A likelihood analysis is used to determine the fluctuation power spectrum, followed by a Wiener Filter (WF) analysis to obtain the minimum-variance mean fields of velocity and mass density. Constrained Realizations (CR) are then used to sample the statistical scatter about the WF mean field. The WF/CR method is applied as a demonstration to the Mark III data with 1200 km/s, 900 km/s, and 500 km/s resolutions. The main reconstructed structures are consistent with those extracted by the POTENT method. A comparison with the structures in the distribution of IRAS 1.2Jy galaxies yields a general agreement. The reconstructed velocity field is decomposed into its divergent and tidal components relative to a cube of ...

International Nuclear Information System (INIS)

I have analyzed reduced neutron widths (#GAMMA#_n"0) for the subset of 1245 resonances in the nuclear data ensemble (NDE) for which they have been reported. Random matrix theory (RMT) predicts for the Gaussian orthogonal ensemble (GOE) that these widths should follow a #chi#"2 distribution having one degree of freedom (#nu# = 1) - the Porter Thomas (PT) distribution. Using the maximum-likelihood (ML) technique, I have determined that the #GAMMA#_n"0 values in the NDE are best described by a #chi#"2 distribution having #nu# =0.801 #+-# 0.052, which is 3.8 standard deviations smaller than predicted by RMT. I show that this striking disagreement is most likely due to the inclusion of significant p-wave contamination to the supposedly pure s-wave NDE. Furthermore, when an energy-dependent threshold is used to remove the p-wave contamination, ML analysis yields #nu# = 1.217 #+-# 0.092 for the remaining data, still in poor agreement with the RMT prediction for the GOE. ...

CERN Document Server

Inter-symbol interference (ISI) channels with data dependent Gauss Markov noise have been used to model read channels in magnetic recording and other data storage systems. The Viterbi algorithm can be adapted for performing maximum likelihood sequence detection in such channels. However, the problem of finding an analytical upper bound on the bit error rate of the Viterbi detector in this case has not been fully investigated. Current techniques rely on an exhaustive enumeration of short error events and determine the BER using a union bound. In this work, we consider a subset of the class of ISI channels with data dependent Gauss-Markov noise. We derive an upper bound on the pairwise error probability (PEP) between the transmitted bit sequence and the decoded bit sequence that can be expressed as a product of functions depending on current and previous states in the (incorrect) decoded sequence and the (correct) transmitted sequence. In general, the PEP is ...

International Nuclear Information System (INIS)

There is increasing use of radiofrequency radiation (RFR) in industry for communications, welding, security, radio, medicine, navigation etc. It has been recognised for some years that RFR may interact with cardiac pacemakers and steps have been taken to prevent this interference. It is less well recognised that other metallic implants may also act as antennas in an RFR field and possibly cause adverse health effects by heating local tissues. There are a large and increasing number of implants having metal components which may be found in RFR workers. These implants include artificial joints, rods and plates used in orthopaedics, rings in heart valves, wires in sutures, bionic ears, subcutaneous infusion systems and (external) transdermal drug delivery patches"1. The physician concerned with job placement of such persons requires information on the likelihood of an implant interacting with RFR so as to impair health. The following outlines the approach developed in ...

CERN Document Server

All of the solar system gas giants produce electron cyclotron masers, driven by the solar wind impinging on their magnetospheres. Extrapolating to the planet orbiting tau Boo, various authors have predicted that it may be within the detection limits of the 4-meter wavelength (74 MHz) system on the Very Large Array. This paper reports three epochs of observations of tau Boo. In no epoch do we detect the planet; various means of determining the upper limit to the emission yield single-epoch limits ranging from 135 to 300 mJy. We develop a likelihood method for multi-epoch observations and use it to constrain various radiation properties of the planet. Assuming that the planet does radiate at our observation wavelength, its typical luminosity must be less than about 10^{16} W, unless its radiation is highly beamed into a solid angle Omega << 1 sr. While within the range of luminosities predicted by various authors for this planet, this value is lower than recent ...

Science.gov (United States)

An in-depth industrial hygiene survey was conducted to evaluate worker exposures to phosphine during fumigation of grain at the Early and Daniel Co. grain elevator in Louisville, Kentucky. Stored grain was fumigated using aluminum phosphide. Aluminum-phosphide pellets were also added directly to the grain by the blender as it was poured into the storage containers. Local exhaust ventilation was used at points in the grain-moving system where grain dust was generated. Air samples were taken during full-shift periods at the breathing zone of the weighmaster, two bin floormen, and the blender. Area monitoring samples were also taken. If the operators spend considerable time in the vicinity of a bin which is being filled with grain, there is a likelihood of far greater exposure levels being noted. According to the author, further studies of the use of phosphide products at other elevators should be conducted to determine the effect of environmental and process ...

International Nuclear Information System (INIS)

Employing a recently developed Monte-Carlo model, we study the fission of 240Pu induced by neutrons with energies from thermal to just below the threshold for second chance fission. Current measurements of the mean number of prompt neutrons emitted in fission, together with less accurate measurements of the neutron energy spectra, place remarkably fine constraints on predictions of microscopic calculations. In particular, the total excitation energy of the nascent fragments must be specified to within 1MeV to avoid disagreement with measurements of the mean neutron multiplicity. The combination of the Monte-Carlo fission model with a statistical likelihood analysis also presents a powerful tool for the evaluation of fission neutron data. Of particular importance is the fission spectrum, which plays a key role in determining reactor criticality. We show that our approach can be used to develop an estimate of the fission spectrum with uncertainties several times ...

CERN Document Server

We propose to use alternative cosmic tracers to measure the dark energy equation of state and the matter content of the Universe [w(z) & \\Omega_m]. Our proposed method consists of two components: (a) tracing the Hubble relation using HII-like starburst galaxies, as an alternative to SNIa, which can be detected up to very large redshifts, z~4, and (b) measuring the clustering pattern of X-ray selected AGN at a median redshift of ~1. Each component of the method can in itself provide interesting constraints on the cosmological parameters, especially under our anticipation that we will reduce the corresponding random and systematic errors significantly. However, by joining their likelihood functions we will be able to put stringent cosmological constraints and break the known degeneracies between the dark energy equation of state (whether it is constant or variable) and the matter content of the universe and provide a powerful and alternative rute to measure the ...

Science.gov (United States)

No Abstract Available

Energy Technology Data Exchange (ETDEWEB)

The improvement of startability achieved by chemical ignition promotion at low temperature was studied theoretically and experimentally in terms of compression ratio and cetane number using a small direct injection diesel engine. The findings are as follows: The compression ratio and cetane number vary almost linearly. When the compression ratio increases by 1, the cetane number decreases by about 9. Since almost the same ignition condition at starting can be achieved by adjusting the number of cranking cycles, there is almost no influence of compression ratio and cetane number on ignition delay. When the soak temperature is -10{sup 0}C and the compression ratio is 18, the influence of the cetane number is almost negligible. Given the same starting time, the influence produced by an increase in compression ratio by 1 is equivalent to the influence produced by a ...

Energy Technology Data Exchange (ETDEWEB)

Cross section parameterizations for antiproton production in pp collisions are used to predict the antiproton/proton ratio resulting from a flux of cosmic protons with energy spectral index of 2.6 interacting with a 5 gm/cm/sup 2/ column density of H. (GHT)

International Nuclear Information System (INIS)

1974. Netherlands Baldwin, JE Cambridge Univ. (UK). Cavendish Lab. Reidel.;

Science.gov (United States)

Surface crystallization and surface-to-bulk ratio in high-level waste glasses.

International Nuclear Information System (INIS)

A technique for quantitative analysis of growth plates in varus or valgus deformity about the knee has been developed. Computer-generated regions of interest are placed on magnification scintigraphs to divide distal femoral and proximal tibial physes into four equal segments. The ratio of counts in the medial half to counts in the lateral half was studied in 31 children (22 normal, 9 with angular deformity). Normal ratios were 0.74 to 0.98 for femora and 0.98 to 1.20 for tibias. In eight of nine patients with deformity, the ratio was abnormal; in two patients the ratio returned to normal when the deformity ceased to progress.

Science.gov (United States)

The K alpha / K beta ratio of Mn KX-rays scattered by metallic samples changed remarkably with the geometry between the sample and the (55)Fe source-Si(Li) detector system. On the contrary, this intensity ratio changed little in the cases of non-metallic scatterer samples such as lucite or mylar. This difference is interpreted as due to the occurrence of strong or weak interference in the coherent scattering photons. PMID:7280291

International Nuclear Information System (INIS)

Ksub(#beta#)/Ksub(#alpha#) X-ray intensity ratios have been measured for various elements between Z = 29 and Z = 79 for incident proton energies of 23.6, 32.1 and 43.6 MeV. The results yield no evidence for a variation in ratio with particle energy. (orig.).

International Nuclear Information System (INIS)

The Ksub(#beta#)/Ksub(#alpha# 12) x-ray intensity ratio of the Si K spectrum was measured for proton impact on Si0_2 in the energy range 300-800 keV. An energy dependence of the intensity ratio was found and an explanation is given in terms of multiple ionisation. (author).

International Nuclear Information System (INIS)

The emission lines H#alpha#, H#beta#+[OIII], and L#alpha# have been observed in the high-redshift quasar 1225+31. The ratios of line intensities in 1225+31 are found to be L#alpha#/H#alpha#approx.0.8, H#alpha#/(H#beta#+[OIII]) approx.4, and 4ratio derived by Baldwin on the basis of a composite quasar spectrum, and with direct determination of this ratio in 3C 273 and PKS 0237--23. The ratio H#alpha#/H#beta# is in the range of values found for a sample of low-redshift quasars by Baldwin. The low value for the L#alpha#/H#alpha# ratio cannot be reasonably explained by foreground extinction between the Sun and 1225+31.

Energy Technology Data Exchange (ETDEWEB)

The effects of compression ratio on the history of the fuel-burning process was investigated in a single-cylinder direct-injection diesel engine. Two compression ratios of 21.4 and 18.5 were studied by using two wide and shallow bowls. The engine was operated at different speeds and overall air-fuel ratios, but with constant start-of-combustion timing at top dead center. The measured cylinder pressure was used to derive fuel-burning rate. At all conditions, the low-compression-ratio bowl had a larger mass of premixed-burned fuel and a higher peak specific fuel-burning rate. The fuel-burning rate in the diffusion-controlled phase of combustion decreased with decreasing compression ratio. The resulting combustion duration became longer at reduced compression ratio, and the difference could be as large as 14 crank-angle degrees. For the engine conditions examined ...

International Nuclear Information System (INIS)

The University of Virginia's real-time neutron radiography facility was characterized by measurement of the total neutron flux, gold/cadmium ratio, neutron/gamma ratio, and the effective collimar length-to-aperture diameter (L/D) ratio. The real-time neutron imaging system and collimator were further characterized by measuring the modulation transfer function (MTF) of the system. The collimator effectiveness was measured by using the MTF to determine the ''unparallelism'' of the neutron beam. The computer-based image processing system allowed rapid calculation of the MTF and the collimator effectiveness. The results of these measurements, using no collimator and a simple tube collimator, demonstrated the method's ability to determine the effective L/D ratio. The MTF measurement scheme provided a fast, reliable, and reproducible means of monitoring any changes in the real-time system, including both the ...

Energy Technology Data Exchange (ETDEWEB)

In this paper, an amount of confining reinforcement required for the sufficient flexural ductility of reinforced concrete column was investigated. An equation to calculate the required confining reinforcement ratio was deduced from the analytical investigation and examination on the previous experimental data as to the effects of various factors on the required confining reinforcement ratio. The rotation angle required in plastic hinges, the axial force ratio, the material properties such as concrete strength, and the ratio of core area to the whole area of column sections were employed as the factors. From the examination of the equation, it was shown that the ultimate rotation in plastic hinges calculated by the equation was more conservative than the ultimate rotaion angle of members obtained by test column specimens. It was also indicated that the ultimate rotation angle of members of columns failed ...

Energy Technology Data Exchange (ETDEWEB)

Long crack fatigue threshold ({delta} K{sub th}) and crack closure behaviour of two thermomechanically processed microalloyed (MA) ferrite-pearlite steels are reported. {delta} K{sub th} and crack closure were measured using a dynamic compliance measurement technique. Crack closure was observed at low load ratios (R < 0.5) and the fatigue thresholds decreased with increasing load ratio. In both steels, the closure-free intrinsic threshold ({delta} K{sub eff} {sub th}) was found to be independent of the load ratio. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L{sub {gamma}1} X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L{sub {gamma}1}/L{sub {beta}1} X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).

Science.gov (United States)

... The constancy of the X-ray intensity ratio for each element in Table 8 as the X-ray tube settings were changed shows the excellent compensating ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

Using gasoline as an example of additives for cold start improvement, fuel vapor composition of methanol-gasoline mixtures, fuel evaporation rate in consideration of temperature drop due to heat of fuel evaporation, air fuel ratio, stoichiometric air fuel ratio and excess air ratio of fuel vapor were calculated. The mixture formation of methanol-gasoline mixtures at low temperature in otto cycle engines was studied. Van Laar's empirical formula was used to estimate the partial pressure of high-percentage methanol blends. It was found that the most part of fuel vapor is occupied by gasoline, even when a small amount of gasoline is added to methanol resulting to an extremely small excess air ratio. It is obvious that this vapor pressure adjustment using gasoline is the dominant factor for improvement in cold startability. (10 figs, 1 tab, 10 refs)

Energy Technology Data Exchange (ETDEWEB)

An automotive powertrain includes a conventional piston engine, a continuously variable ratio transmission, an engine speed sensor and a feedback control system. The control system adjusts both the transmission ratio and the throttle valve in the engine carburetor or fuel metering system in response to the position of the accelerator pedal and in response to the crankshaft speed as measured by the engine sensor. The transmission provides extreme overdrive gear ratios which allow the engine to be operated at wide open throttle even during moderate cruising, and, in addition, the engine carburetor or fuel metering system is calibrated to deliver to the engine a stoichiometric air-fuel mixture which is combined, before combustion, with a special proportion of recirculated exhaust gas. As a result of extensive wide open throttle engine operation with the above mentioned intake charge composition, combustion variables are ...

International Nuclear Information System (INIS)

We show that the recently measured asymmetry in helicity-angle spectra of the #LAMBDA#-hyperons, produced in the reaction pp#->#K"+#LAMBDA#p reaction, and the energy dependence of the total pp#->#K"+#LAMBDA#p cross-section can be explained consistently by the same #LAMBDA#p final-state interaction. Assuming that there is no final-state interaction in the #SIGMA#"0 p channel, as suggested by the available data for the reaction pp#->#K"+#SIGMA#"0p, we can also reproduce the energy dependence of the #LAMBDA#/#SIGMA#"0 production ratio and, in particular, the rather large ratio observed near the reaction thresholds. The nominal ratio of the #LAMBDA# and #SIGMA#"0 production amplitudes squared, i.e. when disregarding the final-state interaction, turns out to be about 3, which is in line with hyperon production data from proton and nuclear targets available at high energies. (orig.)

International Nuclear Information System (INIS)

... gamma radiation l conversion m conversion mev range 10-100 mixing ratio

Energy Technology Data Exchange (ETDEWEB)

Polarization measurements are allowing the electric to magnetic form factor ratio of the proton to be determined with unprecedented precision. Recent results indicate that there is a large deviation from unity in the proton form factor ratio around Q{sup 2}{approx_equal}0.35 GeV{sup 2}. Furthermore, the deviation from unity is attributed to a deviation of the electric form factor from standard fits and calculations. A new, partially completed, experiment will significantly improve the existing data and will determine the presence, if any, of a narrow structure in the form factor ratio. The new measurement, combined with the expected high precision cross section measurements, will allow the extraction of individual form factors with unprecedented accuracy at low Q{sup 2}.

Science.gov (United States)

Watkins,. Charles. E. : Effect of Aspect. Ratio on the Air ...... Grover,. H. 3. ; Bishop,. S. M. ; and. Jackson,. L. R. : Fatigue. Strengths of Aircraft ...

International Nuclear Information System (INIS)

Full text: Measurement of K_#beta# to K_#alpha# x-ray intensity ratios are important not only in the field of atomic physics, radiation physics and medical physics, but also to test the validity of assumptions made in the theoretical prediction. The intensity ratios can also give information on the effect of physical and chemical environment of the element in the compound. Many investigators have adopted a single and double reflection geometries to measure the K_#beta# to K_#alpha# x ray intensity ratios to understand the effect of physical and chemical environment on x-ray fluorescence. The targets are excited by a radioactive source of having activity of the order 100 MBq. in order to carry out accurate measurement K_#beta# to K_#alpha# x-ray intensity ratios, we have develop 2#pi# geometrical configuration method : placing a target right on the surface of the detector facing the target to measure the ...

Science.gov (United States)

Manganese, Iodine and Sulfide Concentrations and Peroxide to Oxygen Ratio Measured during the U.S. JGOFS Arabian Sea Process Study ...

Energy Technology Data Exchange (ETDEWEB)

A new class of low aspect ratio toroidal hybrid stellarators is found using more general plasma confinement optimization criterion than quasi-symmetrization. The plasma current profile and shape of the outer magnetic flux surface are used as control variables to achieve near constancy of the longitudinal invariant J* on internal flux surfaces (quasi-omnigeneity), in addition to a number of other desirable physics target properties. We find that a range of compact (small aspect ratio A), high {beta} (ratio of thermal energy to magnetic field energy), low plasma current devices exist which have significantly improved confinement both for thermal as well as energetic (collisionless) particle components. With reasonable increases in magnetic field and geometric size, such devices can also be scaled to confine 3.5 MeV alpha particle orbits.

International Nuclear Information System (INIS)

The determination of ratio of neutron over proton matrix elements by inelastic proton scattering, for 0"+#->#2"+ transitions, is investigated via the comparison between experimental data and theoretical calculations. Calculations into the context of a macroscopic and a microscopic description are performed for a wide mass range nuclei: "1"8O, "3"0Si, "3"2","3"4S, "4"8Ca, "8"8Sr, for which these ratios were determined previously with an independent technique. At that point the choice of the theoretical model may be very critical. It is thus the purpose of this investigation to point out the most suitable model. It is found that in general both theoretical models can be employed for the reliable determination of neutron over proton matrix element ratios.

Energy Technology Data Exchange (ETDEWEB)

One of the unsolved problems of the natural gas dual fuel engine is that there is too much exhaust of Total Hydrogen Carbon(THC) at a low equivalent mixture ratio. To fix it, a natural gas mixed with hydrogen was applied to engine test. The results showed that the higher the mixture ratio of hydrogen to natural gas, the higher the combustion efficiency. And when the amount of the intake air is reached to 90% of WOT, the combustion efficiency was promoted. But, like a case making the injection timing earlier, the equivalent mixture ratio for the nocking limit decreases and the produce of NOx increases. 5 refs., 9 figs., 1 tab.

Science.gov (United States)

... to-continuum X-ray intensity ratio [5]. For ence in the means [7]. In addition, washing samples on thin films, the characteristic X- lymphocytes in NH ...

UK PubMed Central (United Kingdom)

BackgroundAutofluorescence bronchoscopy is more sensitive than conventional bronchoscopy for detecting early airway mucosal lesions. Decreased specificity can lead...Full Text Available

UK PubMed Central (United Kingdom)

In this model, without dark matter, the flat rotation curves of galaxies and the mass-to-light ratios of clusters of galaxies are described quantitatively. The hypothesis is that the agent of gravitational...Full Text Available

Science.gov (United States)

having a triangular wing of aspect ratio 2 with NACA 0005-63 thickness distribution in streamwise planes, and twisted and cambered for a trape- ...

Energy Technology Data Exchange (ETDEWEB)

Since the first commercial operation in 1983, Wolsung unit 1 has experienced several aging phenomena, especially in pressure tubes and feeder pipes. In case of pressure tubes, in-service inspections (ISI) revealed that a major portion of inspected tubes was in contact with calandria tubes. The likelihood of blister formation was a safety concern because it is a potential threat to pressure tube integrity. Wolsung unit 1 was, therefore, subjected to the SLAR (Spacer Location And Reposition) work to separate the contacted pressure tubes from calandria tubes. In this paper, experience of in-service inspection to the pressure tubes will be discussed including the irradiation creep elongation and CIGAR (Channel Inspection and Gauging Apparatus for Reactors) examination of pressure tubes. On the other hand, the problem of wall thinning in the feeder pipes became of great concern since 1996. Inspections, in compliance with CSA N285.4, were conducted in the upper portions ...

Energy Technology Data Exchange (ETDEWEB)

Although the public generally hold positive attitudes towards wind energy, proposals for the construction of new wind farms are often met with strong resistance. In New Zealand, where the government has recently introduced ambitious policy targets for renewable energy generation, negative perceptions of wind farms are increasingly evident and have the potential to prevent the achievement of these targets. This research sets out to examine what influences social resistance to wind farms in New Zealand. Drawing from public submissions on three wind farm proposals, a framework developed by Devine-Wright [Devine-Wright, P., 2005a. Beyond NIMBYism: towards an integrated Framework for Understanding Public Perceptions of Wind Energy. Wind Energy 8, 125-139.] was used as the basis for identification of factors affecting public perceptions of wind farms. The research found firstly that there was no apparent relationship between the proximity of submitters to a proposed wind farm and their ...

International Nuclear Information System (INIS)

The Global Nuclear Energy Partnership (GNEP), recently announced by DOE Secretary Bodman, poses significant new challenges with regard to securing, safeguarding, monitoring and tracking nuclear materials. In order to reduce the risk of nuclear proliferation, new technologies must be developed to reduce the risk that nuclear material can be diverted from its intended use. Regardless of the specific nature of the fuel cycle, nuclear forensics and attribution will play key roles to ensure the effectiveness of nonproliferation controls and to deter the likelihood of illicit activities. As the leader of the DHS nuclear and radiological pre-detonation attribution program, LLNL is uniquely positioned to play a national leadership role in this effort. Ensuring that individuals or organizations engaged in illicit trafficking are rapidly identified and apprehended following theft or diversion of nuclear material provides a strong deterrent against unlawful activities. Key to ...

Energy Technology Data Exchange (ETDEWEB)

Consensus principles from radiation biology were used to describe a generic set of nonlinear, first-order differential equations for modeling of toxicity-induced compensatory cell kinetics in terms of sublethal injury, repair, direct killing, killing of cells with unrepaired sublethal injury, and repopulation. This cellular model was linked to a probit model of hematopoietic mortality that describes death from infection and/or hemorrhage between {approximately} 5 and 30 days. Mortality data from 27 experiments with 851 doseresponse groups, in which doses were protracted by rate and/or fractionation, were used to simultaneously estimate all rate constants by maximum-likelihood methods. Data used represented 18,940 test animals distributed according to: (mice, 12,827); (rats, 2,925); (sheep, 1,676); (swine, 829); (dogs, 479); and (burros, 204). Although a long-term, repopulating hematopoietic stem cell is ancestral to all lineages needed to restore normal ...

DEFF Research Database (Denmark)

Now, more than ever, there are serious health concerns for obese and overweight children. Schools are the perfect setting for children to learn, and this influence can play an important role in preventing children from becoming obese and overweight. The study concerns the behaviors of Health Promoting School (HPS) according to a broad definition of HPS in World Health Organization (WHO), or dependent on schools own health promoting policies. The purpose of study research is to examine whether promoting physical activity among the children at schools in relation to a school health policy such as Food and Nutrition Policy (FNP). This was determined through the comparisons between the FNP based schools and non policy based schools. The study undertook surveys among school food coordinators in the selected Danish primary schools through a web-based questionnaire. The questions in the survey were more focused on physical activity in internal and external school environment. Schools provide ...

Energy Technology Data Exchange (ETDEWEB)

In its current configuration, the IECM provides a capability to model various conventional and advanced processes for controlling air pollutant emissions from coalfired power plants before, during, or after combustion. The principal purpose of the model is to calculate the performance, emissions, and cost of power Plant configurations employing alternative environmental control methods. The model consists of various control technology modules, which may be integrated into a complete utility plant in any desired combination. in conuwt to conventional deterministic models, the IECM offers the unique capability to assign probabilistic values to all model input parameters, and to obtain probabilistic outputs in the form of cumulative distribution functions indicating the likelihood of different costs and performance results. The most recent version of the IECM, implemented on a Macintosh II computer and containing a number of software and model enhancements, was ...

DEFF Research Database (Denmark)

Executive summary 1. Few studies have to date explained consumer attitudes and purchase decisions with regard to genetically engineered food products. However, the increased marketing of genetically engineered food products and the considerable concern that consumers seem to express with regard to the technology call for the development of a theoretical basis for research into these issues. 2. The aim of the paper is to present three models which we have developed to explain consumer attitudes, buying behaviour and attitude change with regard to genetically engineered food products. All three models build on established consumer behaviour theory and on existing and comparable research in the field. 3. Consumer attitudes toward genetic engineering in food products are explained in an attitude model that builds on Fishbein's multiattribute attitude model. The model deviates from Fishbein's model in a number of ways: there is an explicit distinction between perceived benefits and risks ...

International Nuclear Information System (INIS)

Environmental regulatory requirements at both the state and federal level are constantly changing, making it difficult for industry and R ampersand D program managers to project future compliance requirements and costs. Even if a company is trying to keep abreast of various proposed regulatory initiatives, the number of possible combinations of initiatives that could occur in the future seems virtually limitless. Uncertainty associated with potential future environmental compliance requirements makes the identification and evaluation of future investment and R ampersand D opportunities exceedingly difficult, and makes the process of systematic strategic planning increasingly complex. This paper describes a methodology for accounting for uncertain future environmental compliance costs in a systematic, comprehensive manner. Through analysis of proposed initiatives for making future environmental requirements more stringent, forecasting the likelihood of occurrence ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a stochastic model and estimation procedure for analyzing the failure process of a repairable system. We consider repairable systems whose successive interfailure times reveal a significant dependence while showing an insignificant trend. Neither the renewal process nor the non-homogeneous Poisson process are adequate for modeling such failure processes. Especially when the interfailure times show a cyclic pattern, we may consider a switching of the regimes (states) governing the lifetime distribution of the system. We propose a Markov switching model describing the failure process for such a case. The model postulates that a finite number of states governs the distinct lifetime distributions, and the state makes transitions according to a discrete-time Markov chain. Each of the distinct lifetime distributions represents a failure type that may change after successive repairs. Our model generalizes the mixture model by allowing the mixture probabilities to change ...

International Nuclear Information System (INIS)

L_#alpha#/L_l X-ray intensity ratios have been measured in elements Ta, W, Au, Hg, Tl, Pb, Bi, Th and U using L-shell photoionization by 60 keV photons. The present results are found to agree with the calculated values of Scofield within experimental uncertainties. (author).

Energy Technology Data Exchange (ETDEWEB)

An experimental study of second harmonic generation in a copper-vapor pulsed laser with an ADP crystal is presented. The ratio of the conversion into the second harmonic is found to depend on the average power of the exciting radiation. The maximum conversion ratio was 8.5%. Thermal self-defocusing is the main obstacle to obtaining high average powers at the double frequency.

Energy Technology Data Exchange (ETDEWEB)

It is shown that observations of the lithium isotope ratio in high surface temperature Population II stars may be critical to cosmological nucleosynthesis models. In particular, decaying particle scenarios as derived in some supersymmetric models may stand or fall with such observations. 18 references.

Energy Technology Data Exchange (ETDEWEB)

The membrane transport of the two stable lithium isotopes, {sup 6}Li and {sup 7}Li, by erythrocytes has been studied using a dual channel atomic absorption spectroscopic technique. {sup 6}Li appears to be taken up preferentially to {sup 7}Li, in the ratio of 10 to 40%, depending on the concentration of total lithium and on the lithium isotopic ratio in the external medium.

UK PubMed Central (United Kingdom)

Experimental studies have shown that two main estrogen metabolites hydroxylated by CYP1A1 and CYP1B1 in the breast differentially affect breast cell proliferation and carcinogenesis. Although 16α-hydroxyestrone...Full Text Available

International Nuclear Information System (INIS)

In a cold fusion method by electrolysis, a hydrogen occluding material mainly comprising vanadium is used as a material for a negative electrode, and lithium isotopes are incorporated in the material by more than 93%. That is, the ratio of lithium 7 ("7Li) isotope is increased to higher than the natural existent ratio, so that tritium ("3H) concentration in the hydrogen occluding material can be increased, to attain energy at high efficiency. (T.M.).

International Nuclear Information System (INIS)

Chemical influences on the relative Ksub(#nu#)/Ksub(#alpha#) x-ray intensity ratio up to five per cent were found for different chemical constitutions of Cr, Mn, Fe and Cu by very precise PIXE measurements. In the discussion of these effects, screening of 3p electrons by a varying 3d valence charge, as well as polarisational effects are of importance. (author).

Energy Technology Data Exchange (ETDEWEB)

3d occupation numbers of the transition elements corresponding to various types of atomic configurations are calculated by means of the linear muffin-tin orbital (LMTO) method. This data is used with the multiconfiguration Dirac-Fock (MCDF) X-ray intensity ratios to estimate the electron populations of the 3d metals in alloys.

International Nuclear Information System (INIS)

The Monte Carlo transport codes LAHET and MCNP were used to calculate energy fluence spectra at three neutron therapy facilities. The results compare very favourably with measured data. Kerma spectra and the ratio of ICRU muscle tissue kerma to A-150 kerma, along the carbon to oxygen kerma ratio, were determined. Absorbed dose rate calculations are in reasonable agreement with measured values. Use of these codes to study modifications to existing therapy beams is briefly discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

The use of the ratio of the characteristic intensity to the continuum background intensity (P/B ratio) of the X-ray spectrum for a quantitative ion microprobe (IMP) or PIXE (particle induced X-ray emission) analysis of thin biological specimens was proposed previously. The IMP analysis of thick biological specimens is also of considerable practical use. In this paper, the possibility of using the P/B ratio to quantify minor elements in thick biological specimens is investigated. The epoxy resin based standards with gradual concentrations of KCNS up to 0.6 mol/kg and NBS bovine liver were analyzed by a 27 MeV {alpha} particle microprobe. The measured peak to background ratios (between 4.4 to 5.7 keV) agreed well with the theoretical calculations. The calculations showed that the concentration dependence of the P/B ratios was determined mainly by the absorption of X-rays in specimens. ...

International Nuclear Information System (INIS)

We examined whether proton magnetic resonance spectroscopy (MRS) could provide accurate information on histological grade and cell proliferation in astrocytomas. We studied 23 patients with astrocytomas: five grade II, 10 grade III and eight with grade IV (glioblastoma multiforme). We performed proton MRS and determined the Ki-67 labeling index (LI), a tumour proliferation marker, in the same areas of the astrocytomas, and examined the statistical relationship between proton MRS and Ki-67 LI. The N-acetylaspartate (NAA)/creatine-phosphocreatine (Cr) and NAA/choline (Cho)-containing compound ratios were always significantly lower and the Cho/Cr ratios significantly higher than those for normal brain. The Cho/Cr ratio correlated positively and the NAA/Cho ratio inversely with Ki-67 LI. These findings suggest that the Cho signal in proton MRS reflects cellular proliferation. In Kaplan-Meier survival ...

International Nuclear Information System (INIS)

K#beta#-to-K#alpha# X-ray intensity ratios of Ti, V, Cr, and Co in pure metals and their disilicide compounds have been measured following excitation by 59.54 keV #gamma#-rays from a 200 mCi "2"4"1Am point-source. The K#beta#-to-K#alpha# intensity ratios of all these metals in the disilicide compounds are found to be less than the corresponding ratios for pure metals. Comparison of the measured K#beta#-to-K#alpha# intensity ratios for the disilicides and pure metals with the multiconfiguration Dirac-Fock calculations indicates increase of the 3d electron populations of Ti, V, Cr, and Co in the disilicides from their pure metal values suggesting the rearrangement of electrons between 3d and 4s states of the individual metal atom. This rearrangement is found to be opposite to that observed in our previously reported work on NiSi_2 and CuSi_2.

International Nuclear Information System (INIS)

For the purpose of risk estimates from radiation carcinogenesis including leukemogenesis and radiation genetic effects, the biological significant dose is not the tissue kerma in air but the absorbed dose in organ or tissue with respect to carcinogenic and leukemogenic effects or genetic effects. In order to estimate organ or tissue dose from the tissue kerma in air, a ratio of the organ or tissue dose to the tissue kerma in air for survivors in Hiroshima and Nagasaki was calculated with the aid of the Snyder's mathematical phantoms constructed so as to simulate the body shape of survivors aged 5, 10 years old and adult at the time of atomic bomb detonations. The ratios were corrected for the angular distribution of atomic bomb radiations, assuming an anisotropic angular distribution for the survivors exposed to the atomic bombs in open air and the isotropic distribution for the survivors incide a Japanese house or other structures. The ...

International Nuclear Information System (INIS)

10%Pt/C catalysts were prepared by liquid reduction method. PTFE and Pt/ C catalysts were adhered to porous metal and hydrophobic Pt/C/PTFE catalysts were prepared. The structure and size of Pt crystal particles of Pt/C catalysts were analyzed by XRD, and their mean size was 3.1 nm. The dispersion state of Pt/C and PTFE was analyzed by SEM, and they had good dispersion mostly, but PTFE membrane could be observed on local parts of Pt/C/PTFE surface. Because of low hydrophobicity, Pt/C/ PTFE catalysts have low activity when the mass ratio of PTFE and Pt/C is 0.5: 1, and their catalytic activity increases markedly when the ratio is 1:1. When the ratio increases again, more Pt active sites would be covered by PTFE and interior diffusion effect would increase, which result in the decrease of catalytic activity of Pt/C/PTFE. By PTFE pretreatment of porous metal carrier, the activity of Pt/C/PTFE catalysts decreases when the mass ...

Science.gov (United States)

New sets of cross sections for the production of krypton isotopes from targets of Rb, Sr, Y, and Zr were constructed primarily on the bases of experimental excitation functions for Kr production from Y. These cross sections were used to calculate galactic-cosmic-ray and solar-proton production rates for Kr isotopes in the moon. Spallation Kr data obtained from ilmenite separates of rocks 10017 and 10047 are reported. Production rates and isotopic ratios for cosmogenic Kr observed in ten well-documented lunar samples and in ilmenite separates and bulk samples from several lunar rocks with long but unknown irradiation histories were compared with predicted rates and ratios. The agreements were generally quite good. Erosion of rock surfaces affected rates or ratios for only near-surface samples, where solar-proton production is important. There were considerable spreads in predicted-to-observed production rates of /sup 83/Kr, ...

CERN Document Server

We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant[Y/Zr] and [Sr/Y] values in the field stars places strong limits on the contributions of the weak s-process and the main s-process to the light neutron-capture elements. Stars in the globular cluster M 15 possess lower [Y/Zr] values than the field stars. There is a large dispersion in [Y/Ba]. Because the r-process is responsible for the production of the heavy elements in the early Galaxy, these dispersions require varying light-to-heavy ratios in r-process yields.

Energy Technology Data Exchange (ETDEWEB)

Phosphate/chromate and accelerated chromate coatings were produced on commercially available aluminium. The Cr, P and Fe components of the conversion coatings were determined by radioactive tracer technique. The tracer technique was combined with ion-exchange and film-sectioning methods to determine the chromium(III)/total chromium ratio in the accelerated chromate coating. It was found that during the acidic dissolution of the conversion coating the chromium(III)/total chromium ratio may suffer changes. The film-forming components in the metal/bath interface are supersaturated and deposited onto the aluminium. The identified components of the accelerated chromate coatings are Cr(OH)sub(3), Cr(OH)CrOsub(4) and Crsub(4)(Fe(CN)sub(6))sub(3) and the chromium(III)/total chromium ratio was found to be cca. 2/3. (author). 11 refs.; 5 figs.

International Nuclear Information System (INIS)

A more complete level scheme is presented here for the decay of "1"8"7Pt, incorporating many new lines and levels up to 2.4 MeV. Emphasis has been placed on the extraction of multipole mixing ratios from nuclear orientation data. Analysis of that data, however, required a more complete understanding of the level structure (including, in particular, branching ratios, conversion coefficients, and level feedings), prompting the collection of new spectroscopy data. The low-lying, positive-parity levels are described in terms of (odd-proton) single-particle Nilsson states coupled to a triaxial core. Multipole mixing ratios are compared to those calculated in the Particle-Plus-Triaxial-Rotor Model. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A new class of low aspect ratio toroidal hybrid stellarators is found using a more general plasma confinement optimization criterion than quasisymmetrization. The plasma current profile and shape of the outer magnetic flux surface are used as control variables to achieve near constancy of the longitudinal invariant J{sup {asterisk}} on internal flux surfaces (quasiomnigeneity), in addition to a number of other desirable physics target properties. A range of compact (small aspect ratio A), low plasma current devices have been found with significantly improved confinement, both for thermal as well as energetic (collisionless) particle components. With reasonable increases in magnetic field and geometric size, such devices can also be scaled to confine 3.5 MeV alpha particle orbits.

British Library Electronic Table of Contents (United Kingdom)

Field-annealed Co-based amorphous ribbon (Metglas? 2705M) with a meander structure is fabricated by MEMS technology and the giant magnetoimpedance (GMI) effects are studied at different magnetic fields and frequencies. The maximum longitudinal GMI ratio of the ribbon is 193.7% and the magnetic field sensitivity is 17.4%/Oe. The maximum GMI ratio of the meander ribbon is much larger than the single strip ribbon mainly due to the larger change ratio of inductance L. The sensitivity of an output U reach up to 10 V/A and U thermal fluctuation is less than 15 mV in the temperature range of ?20 to 40?C. This meander shape ribbon can be considered as a good candidate for the GMI-based sensor fabrication.

Energy Technology Data Exchange (ETDEWEB)

The production of the {lambda}- and {sigma}{sup 0}-hyperons has been measured via the pp{yields}pK{sup +}{lambda}/{sigma}{sup 0} reaction at the internal COSY-11 facility in the excess energy range between 14 and 60 MeV. The transition of the {lambda}/{sigma}{sup 0} cross-section ratio from about 28 at Q{<=}13 MeV to the high-energy level of about 2.5 is covered by the data showing a strong decrease of the ratio between 10 and 20 MeV excess energy. Effects from the final-state interactions in the p-{sigma}{sup 0} channel seem to be much smaller than in the p-{lambda} channel. Estimates of the effective range parameters are given for the N{lambda} and the N{sigma} systems. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Combustion characteristics of Korean anthracite in a circulating fluidized bed and freeboard were investigated. A test coal was selected with heating value of 4,429kcal/kg and ash content of 38%. Characteristics of combustion, sorbent effect on desulphurisation and emission of SO{sub x} and NO{sub x} were monitored by varying process variables such as feed rate, (Ca+K)/S ratio, and excess air ratio at the given properties of coal. Optimum operating conditions were studied by analysing: axial profiles of temperature, effect of excess air ratio, characteristics of loopseal and bag filter ashes, and emission of toxic gases. 9 refs., 9 figs., 3 tabs.

British Library Electronic Table of Contents (United Kingdom)

Purpose - This study seeks to explore the aerodynamic performance of wings with different shapes at low Reynolds numbers. Design/methodology/approach - The airfoils of these wings are made from aluminum plates, and the maximum cord length and wingspan are 15?cm. Wings A to D are plates with 6 percent Gottingen camber but different wing planforms. The forward-half sections of wings E and F are dragonfly-like, whereas the rear-half sections of wings E and F are flat and positively cambered, respectively. The aspect ratios of these wings are close to one, and the ratios of plate thickness to the maximum cord length are 1.3 percent. Experimental results indicate that the wings with Gottingen camber have a superior lift and lift-to-drag ratio, whereas the wings with dragonfly-like airfoils perf...

Energy Technology Data Exchange (ETDEWEB)

The invention is associated with organic geochemistry and may be used in conducting geological exploration operations for oil and gas. The purpose of the invention is to increase the precision of the method for determining the genesis of bitumoids. This is achieved through determining the isotopic composition of nickel or vanadium and from the anomalously high values of the isotopic ratio of Ni-58 to Ni-62 or from the anomalously low values of the isotopic ratio of vanadium, a conclusion is drawn about the epigenetic nature of the bitumoids. The proposed method is characterized by greater resolution due to the fact that the values of the isotopic ratios for oil bearing and water bearing structures are essentially not superimposed. The proposed method exceeds the resolution of metal metering studies in conducting geological exploration for oil and gas by 2 to 3 times.

Energy Technology Data Exchange (ETDEWEB)

Critics of higher fuel economy standards for vehicles have long argued that improving vehicle fuel economy will require reducing vehicle weight, and that would result in an increase in the number of fatalities from vehicle crashes. Several researchers have estimated that an across-the-board reduction of vehicle weight would reduce passenger safety (Evans 1991; Kahane 1997; U.S. GAO 1994). However, little research has been done on the relationship of vehicle size and fatality rates, independent of weight (see, however, Joksch, Massie, and Pichler 1998). In this report we review previous analyses of the relationship of vehicle weight and safety. We do this to study the opportunities to improve fuel economy in a more sophisticated way than across-the-board mass reduction. The aim is to explore improvements in traffic safety by making selected vehicle groups lighter, and retaining or enlarging selected vehicle dimensions. Unfortunately, the effects of size and mass have not been accurately ...

Energy Technology Data Exchange (ETDEWEB)

The K{beta}-to-K{alpha} X-ray intensity ratio of Ni in Ni{sub 3}Si, Ni{sub 2}Si and NiSi has been determined by energy dispersive X-ray fluorescence technique. It is found that the intensity ratio of Ni decreases from pure Ni to Ni{sub 2}Si and then increases from Ni{sub 2}Si to NiSi, in good agreement with the electronic structure calculations cited in the literature. We have also performed band structure calculations for pure Ni in various atomic configurations by means of linear muffin-tin orbital method and used this data with the normalized theoretical intensity ratios cited in the literature to estimate the 3d-occupation numbers of Ni in Ni-Si alloys. It is emphasized that investigation of alloying effect in terms of X-ray intensity ratios should be carried out for the stoichiometric alloys in order to make reliable and quantitative comparisons between theory and experiment in transition metal ...

UK PubMed Central (United Kingdom)

The effect of TP (triosephosphates:glyceraldehyde-3 phosphate, GAP, +dihydroxyacetone phosphate, DHAP) on respiration, phosphorylation and matrix ATP/ADP ratios of isolated oat mesophyll mitochondria...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundPlasmodium falciparum morbid and fatal risks are considerably higher in areas supporting parasite prevalence ≥25%, when compared with low transmission...Full Text Available

Science.gov (United States)

The ratio of particle velocity to translation speed exceeds 1 for 98% of .... The westward movement of the meandering jet and eddy system transports nutrient- rich ...... J. Hydrometeor., 4, 1044-1066. Gedney, N., P. M. Cox, H. Douville, ...

International Nuclear Information System (INIS)

The problem on the ratio between the instability of physical systems and tachyons is discussed. It is shown that the tachyons participation in the real physical process of the system rearranging does not contradict any principles. It is noted that the tachyons constitute the most significant element of the systems, identifying the instability relative to the phase transition into the stable state.

Science.gov (United States)

... in Ti-6Al-4V has been studied quite thoroughly [5-7], much of the work resulting from the Air Force-sponsored High Cycle Fatigue initiative [8]. In ...

UK PubMed Central (United Kingdom)

Receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) play key roles in the pathogenesis of glucocorticoid-induced osteoporosis (GIO). The aim of our study was to determine whether the...Full Text Available

UK PubMed Central (United Kingdom)

Some of most used indicators in marine ecology are nucleic acid-derived indices. They can be divided by target levels in three groups: 1) at the organism level as ecophysiologic indicators, indicators...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A new hydroxyiminoamide ligand, 1-(2-nitroimidazole-1-yl)-propanhydroxyiminoamide (N2IPA) was synthesized. The biodistribution of {sup 99m}Tc-N2IPA in mice bearing S180 tumor demonstrated that the complex showed a selective accumulation in tumor and slow clearance from it. The tumor-to-tissue uptake ratios increased with time. At 4 hours after injection, the uptake ratios of tumor to muscle, blood, liver, heart, and lung reached 8.4, 1.5, 0.6, 2.9, and 2.3, respectively. Moreover, the tumor-to-liver uptake ratio steadily increased to 0.9 at 8 hours and 2.3 at 24 hours. The complex showed little uptake and quick clearance in blood, lung and other organs. Compared with other proposed hypoxia-imaging agents, this novel agent has advantages of higher tumor-to-muscle and tumor-to-blood uptake ratios and easier synthesis.

UK PubMed Central (United Kingdom)

OBJECTIVENicotinamide adenine dinucleotides (NAD⁺ and NADH) play a crucial role in cellular energy metabolism, and a dysregulated NAD⁺-to-NADH ratio is implicated...Full Text Available

UK PubMed Central (United Kingdom)

OBJECTIVEModerately preterm infants (30–34 6/7 weeks’ gestational age) represent the largest population of NICU residents. Whether their clinical...Full Text Available

Wastenet

UNEP will provide in the first CPR quarterly report of 2011 the financial statements for 2010. ...for assessing and rating programme performance UNEP to work with the CPR to identify better ways of streamlining reporting requirements ...in 2011 to achieve the ratios requested by the CPR dependent on receipt of contributions originally planned for the

Energy Technology Data Exchange (ETDEWEB)

In isolated rat adipocytes, insulin inhibits lipolysis to a greater extent than would be predicted by the decrease in (-/+)cAMP activity ratio of cAMP-dependent protein kinase (A-kinase), from which it was speculated that insulin promotes the dephosphorylation of hormone-sensitive lipase. They have examined the phosphorylation state of cellular proteins under conditions of varying A-kinase activities in the presence and absence of insulin. Protein phosphorylation was determined by SDS-PAGE electrophoresis of extracts from /sup 32/P-loaded cells; glycerol and A-kinase activity ratios were measured in the cytosolic extracts from control, non-radioactive cells. Increased protein phosphorylation in general occurred over the same range of A-kinase activity ratios, 0.1-0.3, associated with increased glycerol release. The insulin-induced decrease in lipolysis was associated with a decrease in the /sup 32/P content of several ...

International Nuclear Information System (INIS)

In this paper, some results of the indoor radon concentration measurements are presented. Kodac track detectors LR 115, bare and in a cup were used for these measurements. Average winter/summer ratio was determined for the town of interest. (author). 5 refs, 1 fig., 1 tab.

Science.gov (United States)

An understanding of the mechanism of generation of Lg from underground nuclear explosions is essential for seismic monitoring and source discrimination. Near-source scattering of explosion-generated Rg into S appears to be responsible for the low-frequenc...

International Nuclear Information System (INIS)

The EMS effect is explained in the flucton model as a consequence of scale invariance violation. Nontrivial behaviour of the ratio between structural functions and production cross sections for lepton pairs for different nuclei at x > 1 is predicted.

International Nuclear Information System (INIS)

The purpose of this study was to evaluate the usefulness of dynamic MRI for femoral head perfusion. Objects were 64 femoral heads of 44 normal cases (20-95 years old), 10 cases (33-90 y) of femoral neck fracture and 8 cases (61-86 y) using steroid due to articular rheumatism, nephrosis and other diseases. Siemens 1.0 T Magneton Impact with body array coil was used for dynamic MRI by the fast low-angle shot 2D method for every 17 sec interval. Gd-DTPA was injected intravenously. ROI was defined in the center of femur head and of trochanter to monitor their values for the dynamic curve. Evaluation was done on the ratio of enhancement ratio (ER) in the head/trochanter and on the curve in both heads. In normal cases, the head ER was significantly lower in >60 years old cases. There was neither significant correlation between their head/trochanter ER ratios nor significant difference between their dynamic curves. In fracture ...

UK PubMed Central (United Kingdom)

Hemoglobin and zinc protoporphyrin (ZPP) tests are commonly used to screen for iron deficiency, but little research has been done to systematically evaluate the sensitivity and specificity of these...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Attention deficit hyperactivity disorder (ADHD) is known as a psychiatric disorder in childhood associated with dopamine dysregulation. We investigated dopamine transporter (DAT) density in children with ADHD in the present study using {sup 123}I-IPT SPECT and postulated that an alteration in DAT density in the basal ganglia (BG) is responsible for dopaminergic dysfunction in children with ADHD. 9 durg-naive children with ADHD and 6 normal children were included in the study. We performed brain SPECT 2 hours after administration of {sup 123}I-IPT and made both quantitative and qualitative analyses for assessment of specific/nonspecific DAT binding ratio in the BG. We investigated the correlation between the severity scores of ADHD symptoms in children with ADHD assessed with ADHD rating scale and specific/nonspecific DAT binding ratio in the BG. Drug-naive children with ADHD showed a significantly incresed specific/nonspecific DAT binding ...

UK PubMed Central (United Kingdom)

Parallel imaging reconstructions result in spatially varying noise amplification characterized by the g-factor, precluding conventional measurements of noise from the final...Full Text Available

Science.gov (United States)

The structural features of 25mm combustible cartridge cases, manufactured for this program and having nitrocellulose/resin/fiber ratios of 85/10/5, 80/15/5, 75/20/5 and 75/10/15, were characterized through permeability measurements, respectively, about 10...

Energy Technology Data Exchange (ETDEWEB)

Methods were studied for using sugar as a feed additive for converting the sodium-bearing wastes stored at the Idaho Chemical Processing Plant into granular, free flowing solids by fluidized-bed calcination at 500{degrees}C. All methods studied blended sodium-bearing wastes with Fluorinel wastes but differed in the types of sugar (sucrose or dextrose) that were added to the blend. The most promising sugar additive was determined to be sucrose, since it is converted more completely to inorganic carbon than is dextrose. The effect of the feed aluminum-to-alkali metal mole ratio on calcination of these blends with sugar was also investigated. Increasing the aluminum-to-alkali metal ratio from 0.6 to 1.0 decreased the calcine product-to-fines ratio from 3.0 to 1.0 and the attrition index from 80 to 15%. Further increasing the ratio to 1.25 had no effect.

UK PubMed Central (United Kingdom)

Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [³H]IAA...Full Text Available

UK PubMed Central (United Kingdom)

The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of ¹⁴C/C ratio, independent of chemical separation procedures....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A method is presented to derive the absolute dimensions of early-type detached binaries by combining the observed parameters with results of evolutionary computations. The method is used to obtain the absolute dimensions of nine close binaries. We find that most systems have an initial masss ratio near 1.

UK PubMed Central (United Kingdom)

The minimum energy conformations of dApdA have been examined for their suitability as buildings blocks of the single stranded coil form of polynucleotides. Calculations of the characteristic ratio C...Full Text Available

International Nuclear Information System (INIS)

In compliance with Article 20 of the sustainable radioactive materials and waste management act dated 28 June 2006, the CEA and AREVA are required every three years to revise the cost of decommissioning their facilities and to provide the necessary assets by constituting a dedicated fund. For the 2007 revision the CEA used ETE-EVAL V5. Similarly, AREVA reevaluated the cost of decontaminating and dismantling its facilities at La Hague, as the previous estimate in 2004 did not take into account the complete cleanup of all the structural work. ETE-EVAL V5 is a computer application designed to estimate the cost of decontamination and dismantling of basic nuclear installations (INB). It has been qualified by Bureau Veritas and audited. ETE-EVAL V5 has become the official software for cost assessment of CEA civilian and AREVA decommissioning projects. It has been used by the DPAD (Decontamination and Dismantling Projects Department) cost assessment group to estimate the cost of ...

International Nuclear Information System (INIS)

The measurement of K(alpha)/K(beta) X-ray intensity ratio indicates the excitation process and the chemical state of the atom examined. Theoretical considerations on the origin of this property are presented. The difference of these ratios following photoionization and electron capture are calculated by a computer code generating transition matrix elements. The theoretical assumptions involved in the codes are tested by comparing the experimental and calculated data concerning 3d transition element atoms. (D.Gy.).

British Library Electronic Table of Contents (United Kingdom)

The mechanism of abrupt increase of the giant magneto impedance (GMI) ratio in the ion irradiated Co-based amorphous ribbon has been investigated. The grazing incident X-ray diffraction and transmission electron microscope were used to characterize the samples before and after ion irradiation. The GMI-ratio considerably increased in the ion irradiated samples and the GMI response showed strong dependence on the driving frequencies. The Barkhausen noise (BN) signals are increased for the Ar ion irradiated sample with dose of 1x10^1^7 ion/cm^2. The results are interpreted in terms of GMI variation associated with domain wall dynamics.

International Nuclear Information System (INIS)

Results of monitoring milk and tap water in New York City are presented. The New York City sample is a monthly composite of pasteurized milk purchased daily at retail stores. The monthly "9"0Sr to calcium ratios for New York City since the inception of the sampling program in 1954 are presented. Samples of New York City tap water are taken daily, so that by the end of the month, approximately 100 liters have been collected. The available cesium-137 data expressed as the "1"3"7Cs to "9"0Sr ratio are also given.

International Nuclear Information System (INIS)

The validation of the forecast model for early emergency response to nuclear accidents is evaluated by trace tests in atmosphere in Daya Bay nuclear power site. The simulation experiment of the Daya Bay nuclear power site shows that the particle spreading image and the time-integrated concentration distribution given by plume concentration prediction model can perform the variation of pathway of the pollutant transport, as well as the effects of topography on transport and diffusion of pollutants. The simulation of five trace tests in field shows that 59.1% of ratios between predicted results and observed results are within the range of 10, and 41% of ratios are within the range of 5 approximately. (authors)

Energy Technology Data Exchange (ETDEWEB)

A dual fuel engine control system for controlling the power output of a dual fuel compression ignition engine. The engine includes mixing means for combining an oxidizer and a primary fuel at a substantially constant ratio of oxidizer to primary fuel. The power output of the engine is controlled through the use of a throttle valve controlling the quantity of combustible mixture delivered to the combustion chamber. The fuel control system minimizes the quantity of ignition fuel required by controlling the quantity of combustible mixture rather than the fuel of air ratio. (author) figs.

International Nuclear Information System (INIS)

The K_#beta#/K_#alpha# X-ray intensity ratios are measured for Mn and Fe and for six other elements with Z lying in the range 49<=Z<=82 following electron capture decay and photon excitation using "2"4"1Am and "5"7Co sources. High-resolution Si(Li) and HpGe detector systems were used in the experiments. The dependence of K_#beta#/K_#alpha# values on the mode of excitation in the case of Mn and Fe is attribuited to the chemical effects, while no such dependence is found for the high-Z elements.

Energy Technology Data Exchange (ETDEWEB)

An analysis based on Jaroniec's theory of mixed gas adsorption showed that for two arbitrary adsorbing gas components the ratio of their surface coverages is a simple power function of the ratio of their partial pressures. This result was verified with available experimental data on the adsorption of C/sub 1/-C/sub 4/ hydrocarbon binary mixtures, CO/sub 2//C/sub 2/H/sub 4/, and N/sub 2//CO on various carbons, silica gel, and cesium iodide.

International Nuclear Information System (INIS)

Analysis of data on seedling traits from 20 diverse genotypes revealed significant differences fro most of the seedling traits. Significant estimates of broad-sense heritability were observed for VI, ERI, FRTW, DRTW and R/S ratio. Genetic advance was maximum for VI,ERI and E%. The correlation of VI with ERI and R/S ratio was negative and significant, whereas it was positive and significant with E%, FSHW and DSHW. Characterization of the sorghum genotypes according to Anderson's Metro glyph Statistics revealed five different groups for seedling trails. (authors)

International Nuclear Information System (INIS)

Continuum events represent an eminent source of background in any e+e- experiment. As these have a higher branching ratio than BB-bar events (at BaBar this ratio is estimated to about 3.5) or ?+?- events, efficient continuum background suppression is essential in many analyses. Using Artificial Neural Networks and the Nearest Neighbor Method we developed several selectors which, based only on the global event shape variables, efficiently tag BB-bar events and ?+?- events against the continuum background. These selectors could then be combined with the channel specific information in various types of analyses. The study was done using a parametric Monte Carlo.

Energy Technology Data Exchange (ETDEWEB)

In this study attempts have been made to utilize biomass residues in a proper and efficient way. As a part of these attempts activated charcoal has been produced from coconut shell. The effects of temperature, time and impregnation ratio on activation and yield have also been studied. Experimental results show that higher temperature produces better activation but lower yield. The optimum values for activation time and impregnation ratio in producing activated charcoal were 50 min and 40%, respectively, at 600{sup o}C. (Author)

International Nuclear Information System (INIS)

[F-18]FDG PET brain imaging is an accurate predictor of primary brain tumor grading and prognosis. The purpose of this study was to evaluate simplified [F-18]FDG PET metabolic indices as indicators of proliferative activity of brain tumor cells. Twenty-five patients with glioma were studied with [F-18]FDG PET. From the tissue radioactivity ratios, following tumor metabolic indices were calculated: 1) the tumor-to-whole brain ratio (T/WB), 2) the ratio of tumor-to-contralateral gray matter at the level of centrum semiovale (T/GM), 3) the ratio of tumor-to-contralateral white matter at the level of centrum semiovale (T/WM), 4) the tumor-to-ipsilateral cerebella ratio (T/iCB) and 5) the tumor-to-contralateral cerebellar ratio (T/cCB). A standardized threshold method was used to define ROIs in the tumor areas having representative metabolic activites. Correlations ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports that grinding and polishing affected the orientation of 90[degrees] domains at the surface of lead zirconate titanate (PZT) ceramics. This was quantified by using changes in the intensity ratio of the (002) and (200) X-ray reflections. Grinding unpoled PZT with 600-grit SiC paper gave X-ray intensity ratios similar to those of poled material. This implies that 90[degrees] domain realignments had occurred in the near surface region probed by the X-rays. Grinding poled samples with 600-grit SiC further increased the X-ray intensity ratio beyond that caused by poling, indicating that additional surface reorientation of 90[degrees] domains had occurred. The effects of diamond polishing depended on the size of the diamond particles. The use of 6-[mu]m diamond had no effect on the (002)/(200) intensity ratio of either poled or unpoled samples, while polishing with 15- or 45-[mu]m diamond ...

Energy Technology Data Exchange (ETDEWEB)

Objective: To assess dynamic MRI with Gd-DTPA enhancement for evaluating inflammatory changes in the subacromial bursa. Design and patients: We detected the signal intensity changes in dynamic MRI of the subacromial bursa, and confirmed these macroscopically by arthroscopy and histologically. The signal intensity was measured using built-in software, and the enhancement ratio (E ratio) was calculated from dynamic MR images. In addition, as a parameter of the rate of the increase in the signal intensity from 0 to 80 s, the mean increase per second in the E ratio was obtained as the coefficient of enhancement (CE). The correlation was studied of the E ratio and CE with the arthroscopic findings (redness, villous formation, thickening and adhesion), and of the E ratio and CE with the histological findings (capillary proliferation, papillary hyperplasia, fibrosis and inflammatory cell ...

Energy Technology Data Exchange (ETDEWEB)

The Rb-Sr isotope systematics of bedrock, soil digests, and the cation exchange fraction of soils from a granitic glacial soil chronosequence in the Wind River Mountains, Wyoming, USA, were investigated. Six soil profiles ranging in age from 0.4 to {approximately}300 kyr were studied and revealed that the {sup 87}Sr/{sup 86}Sr ratio of exchangeable strontium in the B-horizons decreased from 0.7947 to 0.7114 with increasing soil age. Soil digests of the same samples showed much smaller variation in {sup 87}Sr/{sup 86}Sr from 0.7272 to 0.7103 and also generally decreased with increasing soil age. Elevation of the {sup 87}Sr/{sup 86}Sr ratios of Sr released by weathering over the soil digest and bedrock values results from the rapid weathering of biotite to form hydrobiotite and vermiculite in the younger soils. Biotite is estimated to weather at approximately eight times the rate of plagioclase (per gram of mineral) in the youngest soil profile ...

International Nuclear Information System (INIS)

The effect that different chemical and physical atomic environments can have on the relative intensities of radiative electron transitions from the filling of K shell vacancies was investigated. The method used involved the detection of photoionization induced X-ray fluorescence. An experimental system based on a hyper pure germanium detector (HPGE) was used to measure the relative K-L and K-M X-ray yields from the photofluorescence of a series of lanthanide elements and compounds. A background subtraction and peak integration strategy was employed which accounted for scattering in the samples and scattering of the flux from the radioisotope photoionization sources. Analysis of the data resulted in a tabulation of relative K/sub #beta#//K/sub #alpha#/ X-ray intensity ratios. The measured relative K/sub #beta#//K/sub #alpha#/ X-ray intensity ratios were compared to the calculated values predicted by the theoretical development of Scofield and ...

International Nuclear Information System (INIS)

The precipitation reaction of some rare earth chlorides (La/Ce/Nd/GdCl3) in a LiCl-KCl molten salt has been carried out by using the oxygen sparging method. In this study, regardless of the oxygen sparging time and the molten salt temperature, oxychlorides (REOCl) for LaCl3, NdCl3 and GdCl3, and an oxide (REO2) for CeCl3 are formed as a precipitate. The conversion of rare-earth chlorides into insoluble precipitates was described by using a conversion ratio. The conversion ratio increased exponentially with the oxygen sparging time and finally showed asymptotic value at 1,023K of the molten salt temperature condition. The conversion ratios of LaCl3, NdCl3 and GdCl3 were increased with the molten salt temperature, however, even though the conversion ratio was increased from 0.660 to 0.995 with increasing molten salt temperature from 823 to 923 K at 60 min of a sparging time, the values of the conversion ...

Energy Technology Data Exchange (ETDEWEB)

Recently, the development of shape memory alloy (SMA) actuators, in the forms of wire, thin film and stent have been found increasingly in the fields of materials science and smart structures and engineering. The increase in attraction for using these materials is due to their many unique materials, mechanical, thermal and thermal-mechanical properties, which in turn, evolve their subsequent shape memory, pseudo-elasticity and super-elasticity properties. In this paper, a common type of SMA actuator, Nitinol wires, were embedded into advanced composite structures to modulate the structural dynamic responses, in terms of natural frequency and damping ratio by using its shape memory and pseudo-elastic properties. A simple theoretical model is introduced to estimate the natural frequency of the structures before and after actuating the embedded SMA wires. The damping ratios of different SMA composite beams were measured through experimental ...

International Nuclear Information System (INIS)

K?-to-K? X-ray intensity ratios of Ti and Ni have been measured in pure metals and in alloys of TixNi1-x (x=0.7, 0.6, 0.5, 0.4 and 0.3) following excitation by 22.69 keV X-rays from a 10 mCi 109Cd radioactive point source. The valence-electron configurations of these metals were determined by corporation of measured K?-to-K? X-ray intensity ratios with the results of multiconfiguration Dirac-Fock calculation for various valence-electron configurations. Valence-electron configurations of 3d-transition metals in alloys indicate significant differences with respect to the pure metals. Our analysis indicates that these differences arise from delocalization and/or charge transfer phenomena in alloys. Namely, the observed change of the valence-electron configurations of metals in alloys can be explained with the transfer of 3d electrons from one element to the other element and/or the rearrangement of electrons between 3d and 4s, 4p states of ...

Energy Technology Data Exchange (ETDEWEB)

We obtained the ratios of {sup 134}Cs/{sup 137}Cs and {sup 154}Eu/{sup 137}Cs in spent PWR fuels with gamma scanning equipment of irradiated material examination facility. The fuel segments, of which the burn-up is about 40 GWD/MTU and its cooling time is 8.4 years, are prepared in Post Irradiated Examination Facility and transported to IMEF. By considering of multi-peaks of {sup 134}Cs and {sup 154}Eu, we obtained the relative efficiency of the gamma scanning system as a function of energy. And finally we obtained the number ratios of radioactive nuclides in 72 fuel pellets, radioactive {sup 134}Cs/{sup 137}Cs and {sup 154}Eu/{sup 137}Cs. (author). 4 refs., 27 tabs., 28 figs.

Energy Technology Data Exchange (ETDEWEB)

Hydrogenation of carbon monoxide at 101.3 kPa has been studied over a series of ion-exchanged Ru catalysts supported on NaX, NaY, KL, Na mordenite, and HY zeolites. The type of zeolite had pronounced effects on the activity and selectivity of the Ru. The specific activity would appear to be related to the dispersion of reduced ruthenium in the zeolite. Methane selectivity, however, seems to be strongly influenced by the type and concentration of alkali cations remaining in the ion-exchanged zeolite. These cations appear to promote chain growth much as traditional alkali promoters would, though perhaps more indirectly. Due to bifunctional properties of the zeolite-supported catalysts, a significant fraction of C/sub 4/ was in the form of isobutane. Formation of isobutane seems to be related to either the Si/Al ratio in the zeolites or the concentration of the remaining alkali cations, but not to the OH concentration. In addition, H/sub 2/ chemisorption at 25/sup 0/C ...

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations are being conducted on a single-cylinder direct-injection diesel engine to examine the effects of combustion chamber specifications and swirl ratios on the heat release and transient heat transfer characteristics. Heat rejection was examined on the basis of heat release calculations using cylinder pressure time histories. Transient surface temperature data obtained from stationary locations in the piston and cylinder head were used as the basis for determining the transient heat flux rates. The results showed good agreement with the heat rejection calculated from cylinder pressure data and that transient heat flux in a piston cavity was reduced with the larger cavity diameter and a higher swirl ratio. On the other hand, a transient heat flux in a piston head was not changed by the cavity diameter and swirl ratio. 5 refs., 19 figs.

Science.gov (United States)

% In this work we investigated, in the Smooth Particle Hydrodynamics (SPH) framework, the development of spiral structures and shock fronts in the radial flow of accretion discs in close binary systems. These shock waves take place when the initially supersonic radial flow penetrating the disc bulk, reduces substantially its speed becoming suddenly subsonic. To this purpose, keeping constant the mass of the compact primary (M1 = 1 MO ), the separation between the two components and the injection speed at the inner Lagrangian point L1 (close to the local sound speed), we carried out 2D SPH simulations for four values of the stellar mass ratio M2/M1. We worked out 2D models because the damping effect of the artificial viscosity is too strong in 3D. Furthermore, the 2D environment seems the most suitable in order to evidence shock fronts in highly compressible gases. The results show that spiral structures and shock fronts develop for low values of M2/M1, whilst they ...

International Nuclear Information System (INIS)

Quantitative assessment of bone scintigraphy was performed in fifty-six patients with hip joint disease including femoral neck fracture, aseptic necrosis of the femoral head, traumatic dislocation of the hip, Perthes disease, and transient synovitis of the hip. In the static study, bone scintigraphy was obtained 3 hours after injection of sup(99m)Tc-MDP by gamma camera equipped with a computer and uptake ratios were calculated. In the dynamic study, bone scintigraphy was performed in one, 3 and 5 hours after injection of radionuclide. Femoral head uptake ratio was markedly decreased in osteonecrosis following femoral neck fracture and characteristically increased in aseptic necrosis of the femoral head but prolonged retention of sup(99m)Tc-MDP could be observed. Uptake ratios of epiphysis were decreased in Perthes disease but normal in transient synovitis of the hip. Static and dynamic study of bone scintigraphy may be ...

International Nuclear Information System (INIS)

A 2-year follow-up regarding healing complications, such as redisplacement, nonunion, and segmental collapse of the femoral head, was performed in 306 patients operated on for femoral neck fracture and examined with "9"9"mTechnetium-MDP scintimetry within 2 weeks postoperatively. Scintimetric evaluation was performed by selecting regions of interest over the femoral head on the fracture side and the intact side and by comparing the uptake. A femoral head ratio fractured/intact side thus was obtained. Of 199 patients with an intact femoral head uptake (ratio #<=# 1.0), 181 showed no signs of healing complications at 2 years, whereas 18 had developed healing complications. Of 107 cases with a deficient femoral-head uptake (ratio < 1.0), 96 had developed healing complications within 2 years from the operation, while 11 cases had no signs of radiographic complications. We conclude that "9"9"mTc-MDP scintimetry performed ...

Energy Technology Data Exchange (ETDEWEB)

The optoelectronic compounds of GaAs and ZnSe are difficult to analyze by PIXE (particle-induced X-ray emission) due to the strong absorption of the As and Se K{sub {alpha}} X-rays. As part of a program to investigate optoelectronic materials using ion beam techniques, we have explored the possibility of using the high sensitivity of PIXE to check these materials for stoichiometry and dopant concentrations. The K{sub {alpha}} X-ray intensity ratios of Ga to As and Zn to Se have been investigated using H beams of 0.5 to 2.5 MeV and He beams of 1.0 to 2.5 MeV. The variation in the X-ray intensity ratio with beam energy and target thickness is modelled in terms of the cross section for X-ray production and the absorption coefficients of the X-rays in the target. The results of this model show the experimental conditions that must be satisfied in order that the X-ray intensity ratios are not strongly affected by X-ray ...

CERN Document Server

Recently PAMELA released their first results on the positron and antiproton ratios. Stimulated by the new data, we studied the cosmic ray propagation models and calculated the secondary positron and antiproton spectra. The low energy positron ratio can be consistent with data in the convection propagation model. Above $\\sim 10$ GeV PAMELA data shows a clear excess on the positron ratio. However, the secondary antiproton is roughly consistent with data. The positron excess may be a direct evidence of dark matter annihilation or decay. We compare the positron and anti-proton spectra with data by assuming dark matter annihilates or decays into different final states. The PAMELA data actually excludes quark pairs being the main final states, disfavors gauge boson final states. Only in the case of leptonic final states the positron and anti-proton spectra can be explained simultaneously. We also compare the decaying and ...

Energy Technology Data Exchange (ETDEWEB)

For a direct injection diesel engine to exhibit its inherent low-emission characteristics, it is essential to improve control accuracy, in particular under transient operating conditions during which emissions are more noted. A model-based control system is established for exhaust gas recirculation (EGR) and air/fuel ratio, using a diesel-engine/vehicle model established on the CAD control system. Described herein are the results of simulation for optimizing control of transient conditions, and the emission-controlling effects confirmed by the field tests. The tests for verification of the established model have confirmed that there are good agreements between the simulated and observed results in terms of air/fuel ratio changing with EGR ratio, exhaust and intake gas and pressure levels, and vehicle speed. The model will be applicable to assessment of emission characteristics under varying conditions. Simulation of the ...

Energy Technology Data Exchange (ETDEWEB)

The paper reported on an experiment on measurement of concentration of highly concentrated coal slurry using microwaves carried out at Miike coal preparation works. The purpose of the experiment was to investigate applicability of microwave moisture content measurement of slurry of a mixture of coal and coal particles and to use it to the control of process such as coal preparation and processing. In the experiment, a method for measuring the slurry concentration was adopted in which the container filled with highly concentrated coal slurry was irradiated with microwaves and the damping of strength of the penetrating microwaves was detected. As a result of the experiment, it was found out that there was a big correlation between the capacitive concentration of slurry and the damping ratio of microwaves. When irradiating slurry with microwaves of 1GHz frequency, a big correlation between the concentration and the damping ratio was seen in ...

International Nuclear Information System (INIS)

The measurements of the L X-ray intensity ratio I(L?)/I(L?), I(L?)/I(L?), I(L?)/I(L?), I(L?)/I(L?) and I(L?)/I(L?) for elements Dy, Ho, Yb, W, Hg, Tl and Pb were experimentally determined both by photon excitation, in which 59.5 keV ?-rays from a filtered radioisotope 241Am was used, and by the radioactive decay of 160Tb, 160Er, 173Lu, 182Re, 201Tl, 203Pb and 207Bi. L X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the calculated theoretical values. Theoretical values of the I(L?/L?), I(L?/L?), I(L?/L?), I(L?/L?) and I(L?/L?) intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-section, fluorescence yield, fractional X-ray emission rates, Coster-Kronig transition probabilities. It was observed that present values agree with previous theoretical and other available experimental results.

Energy Technology Data Exchange (ETDEWEB)

A preliminary design effort directed toward a low concentration ratio photovoltaic array system capable of delivering multihundred kilowatts (300 kW to 1000 kW range) in low earth orbit is described. The array system consists of two or more array modules each capable of delivering between 113 kW to 175 kW using silicon solar cells or gallium arsenide solar cells, respectively. The array module deployed area is 1320 square meters and consists of 4356 pyramidal concentrator elements. The module, when stowed in the Space Shuttle's payload bay, has a stowage volume of a cube with 3.24 meters on a side. The concentrator elements are sized for a geometric concentration ratio (GCR) of six with an aperture area of .25 sq. m. The structural analysis and design trades leading to the baseline design are discussed. It describes the configuration, as well as optical, thermal and electrical performance analyses that support the design and overall ...

Energy Technology Data Exchange (ETDEWEB)

Mechanisms that govern transport, accumulation and toxicity of persistent pollutants at interfaces in aquatic ecosystems were the foci of this thesis. Specific attention was paid to humic substances, their occurrence, composition, and role in exchange processes across interfaces. It was concluded that: The composition of humic substances in aquatic surface microlayers is different from that of the subsurface water and terrestrial humic matter. Levels of dissolved organic carbon (DOC) in the aquatic surface microlayer reflect the DOC levels in the subsurface water. While the levels and enrichment of DOC in the microlayer generally show small variations, the levels and enrichment of particulate organic carbon (POC) vary to a great extent. Similarities exist between aquatic surface films, artificial semi-permeable and biological membranes regarding their structure and functioning. Acidification and liming of freshwater ecosystems affect DOC:POC ratio and humic ...

Energy Technology Data Exchange (ETDEWEB)

The infrastructure of the Mexican southeastern coastal zone is affected by corrosion problems which are due, mainly, to the construction bad practices and to the aggressive environmental agents (temp., Relative Humidity, chlorides). The first actions for knowing and controlling them have been taken on the coast of Progreso, Yucatan. Cylinders of solid concrete and others with an embedded rebar were constructed and exposed to the marine environment studying different variables like w/c ratio, time of curing, coated and uncoated rebars, chlorides and CO{sub 2} penetration and place of exposure with respect to the seashore. The cylinders were tested through corrosion potential and polarization resistance measurements in order to detect, in a first stage, the onset and propagation stages of the corrosion processes and to correlate the apparent corrosion current density (Icorr.) with the chloride concentration in the rebar surface. These results are discussed and ...

Energy Technology Data Exchange (ETDEWEB)

Experimental investigation of heat transfer and friction factor characteristics of circular tube fitted with full-length helical screw element of different twist ratio, and helical screw inserts with spacer length 100, 200, 300 and 400mm have been studied with uniform heat flux under laminar flow condition. The experimental data obtained are verified with those obtained from plain tube published data. The effect of spacer length on heat transfer augmentation and friction factor, and the effect of twist ratio on heat transfer augmentation and friction factor have been presented separately. The decrease in Nusselt number for the helical twist with spacer length is within 10% for each subsequent 100mm increase in spacer length. The decrease in friction factor is nearly two times lower than the full length helical twist at low Reynolds number, and four times lower than the full length helical twist at high Reynolds number for all twist ...

International Nuclear Information System (INIS)

TAPP-3 and 4 are the 540 MWe PHWRs having horizontal fuel channel. At normal 100% FP operation there is no boiling in the channel. However, when the power increases due to any transient, the boiling may start in the channel. The main application for critical heat flux (CHP) prediction is to set the operating power with a comfortable margin to avoid CHF occurrence. This margin of CHF can be expressed in terms of minimum critical heat flux ratio (MCHFR), which is the ratio of CHF to local heat flux for the same pressure, mass flux and quality. The CHF depends on power, coolant flow rate as well as coolant condition in the channel. As the power increases the flow reduces in the channel and cooling is degraded. The thermal hydraulic code is developed for present analysis. The output of analysis are CHF prediction quality calculation at axial locations of the maximum rated channel at various power levels and channel flow reduction with increase in ...

Energy Technology Data Exchange (ETDEWEB)

The onset of double-diffusive convection in a couple-stress fluid-saturated horizontal porous layer is studied using linear and weak nonlinear stability analyses. The modified Darcy equation that includes the time derivative term and the inertia term is used to model the momentum equation. The expressions for stationary, oscillatory and finite-amplitude Rayleigh number are obtained as a function of the governing parameters. The effect of couple-stress parameter, solute Rayleigh number, Vadasz number and diffusivity ratio on stationary, oscillatory and finite-amplitude convection is shown graphically. It is found that the couple-stress parameter and the solute Rayleigh number have a stabilizing effect on stationary, oscillatory and finite-amplitude convection. The diffusivity ratio has a destabilizing effect in the case of stationary and finite-amplitude modes, with a dual effect in the case of oscillatory convection. The Vadasz number advances ...

International Nuclear Information System (INIS)

Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP"S"M particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP"S"M particles with a gamma dose equivalent to 100 cycles of use. This irradiation ...

Energy Technology Data Exchange (ETDEWEB)

This research involves the development of an analysis which yielded recommendations regarding the plate thickness at which the effects of transverse shear become significant enough to be taken into consideration during vibration testing of composite plates. The specimens designed using this analysis are to be used for the {open_quotes}inverse{close_quotes} problem of determining through-the-thickness elastic constants as well as in-plane elastic constants from modal vibration response data. The effects of transverse shear were studied over the range of practical plate aspect ratios (length to thickness ratios) and mode numbers. Behavior of composite plates ranging from isotropic to highly orthotropic was studied in order to investigate the effects of transverse shear. Orthotropic plates having in-plane dimensions of 254 x 254 mm and thicknesses varying from 10 mm to 80 mm, with free-free edge boundary conditions, were considered. A methodology ...

Energy Technology Data Exchange (ETDEWEB)

Solid-state nuclear magnetic resonance (NMR) has been used to explore the nanometer-scale structure of Nafion, the widely used fuel cell membrane, and its composites. We have shown that solid-state NMR can characterize chemical structure and composition, domain size and morphology, internuclear distances, molecular dynamics, etc. The newly-developed water channel model of Nafion has been confirmed, and important characteristic length-scales established. Nafion-based organic and inorganic composites with special properties have also been characterized and their structures elucidated. The morphology of Nafion varies with hydration level, and is reflected in the changes in surface-to-volume (S/V) ratio of the polymer obtained by small-angle X-ray scattering (SAXS). The S/V ratios of different Nafion models have been evaluated numerically. It has been found that only the water channel model gives the measured S/V ratios in the ...

International Nuclear Information System (INIS)

Short-lived fission gas release from fuel pellets during irradiation was investigated based on the experimental results of the gas-flow rigs irradiated in the Halden Heavy Water Reactor (HBWR). The release-to-birth (R/B) rates of short-lived fission gas were measured by means of gas-flow measurement during the irradiation experiments. Surface-to-volume (S/V) ratios of fuel pellets and diffusion coefficients of short-lived fission gas release were evaluated from the obtained (R/B) values. The increase of (S/V) ratio agreed well with the point where the fuel temperature exceeded the threshold of 1% fission gas release. This indicates that the interlinkage of fission gas bubbles occurred there. The evaluated diffusion coefficients scattered in the range between 10"-"2"3 and 10"-"1"7 m"2/s, and the effects of fuel type (UO_2 or MOX) were not clearly observed. In addition, it is likely that the restructuring effect of fuel pellet on the diffusion ...

Science.gov (United States)

A rapidly hydrated sorbent for moderate-temperature dry flue gas desulfurization was prepared by rapidly hydrating adhesive carrier particles and lime. The circulation ash from a circulating fluidized bed boiler and chain boiler ash, both of which have rough surfaces with large specific surface areas and specific pore volumes, can improve the adhesion, abrasion resistance, and desulfurization characteristics of rapidly hydrated sorbent when used as the adhesive carrier particles. The adhesion ability of sorbent made from circulation ash is 67.4% higher than that of the existing rapidly hydrated sorbent made from fly ash, the abrasion ratio is 76.2% lower, and desulfurization ability is 14.1% higher. For sorbent made from chain boiler ash, the adhesion ability is increased by 74.7%, the desulfurization ability is increased by 30.3%, and abrasion ratio is decreased by 52.4%. The abrasion ratios of the sorbent made from ...

Science.gov (United States)

The magnetically fluidized bed (MFB) was used as the reactor in a novel semidry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency. Experiments in a laboratory-scale apparatus were conducted to reveal the effects of approach to adiabatic saturation temperature, Ca/S molar ratio and applied magnetic field intensity on SO(2) removal. Results showed that SO(2) removal efficiency can be obviously enhanced by decreasing approach to adiabatic saturation temperature, increasing Ca/S molar ratio, or increasing applied magnetic field intensity. At a magnetic field intensity of 300Oe and a Ca/S molar ratio of 1.0, the desulfurization efficiency (excluding desulfurization efficiency in the fabric filter) was over 80%, while spent sorbent appeared in the form of dry powder. With the SEM, XRD and EDX research, it can be found that the increase of DC magnetic field intensity can make the surface morphology ...

Science.gov (United States)

The Defense Advanced Research Projects Agency (DARPA) inaugurated a program addressing research and development for an Exoskeleton for Human Performance Augmentation in FY!2001. A team consisting of Oak Ridge National Laboratory, the prime contractor, AeroVironment, Inc., the Army Research Laboratory, the University of Minnesota, and the Virginia Polytechnic Institute has recently completed an 18-month Phase I effort in support of this DARPA program. The Phase I effort focused on the development and proof-of-concept demonstrations for key enabling technologies, laying the foundation for subsequently building and demonstrating a prototype exoskeleton. The overall approach was driven by the need to optimize energy efficiency while providing a system that augmented the operator in as transparent manner as possible (non-impeding). These needs led to the evolution of two key distinguishing features of this team's approach. The first is the ''no knee ...

Energy Technology Data Exchange (ETDEWEB)

The groundwater flow and transport model of the Faultless underground nuclear test conducted at the Central Nevada Test Area (CNTA) was accepted by the state regulator and the environmental remediation efforts at the site have progressed to the stages of model validation and long-term monitoring design. This report discusses the long-term monitoring strategy developed for CNTA. Subsurface monitoring is an expensive and time-consuming process, and the design approach should be based on a solid foundation. As such, a thorough literature review of monitoring network design is first presented. Monitoring well networks can be designed for a number of objectives including aquifer characterization, parameter estimation, compliance monitoring, detection monitoring, ambient monitoring, and research monitoring, to name a few. Design methodologies also range from simple hydrogeologic intuition-based tools to sophisticated statistical- and optimization-based tools. When designing the long-term ...

International Nuclear Information System (INIS)

Radiochemical results ("2"3"4U, "2"3"8U, "2"2"6Ra and "2"2"8Ra activities; "2"3"4U/"2"3"8U, "2"2"8Ra/"2"2"6Ra and "2"2"6Ra/"2"3"8U activity ratios) are reported for 31 drinking water samples collected from 8 wells, 12 hot mineral springs, 5 cold springs, and 6 tap water samples. Activities of the Ra isotopes were measured by gamma spectrometry using a low background and high efficiency well type germanium detector. The U isotopes were counted in an alpha spectrometer. The results show that "2"3"8U activity varies between 4.46 and about 308 mBq l"-"1 in wells, 0.59 and 17.88 mBq l"-"1 in hot springs, 2.19 and 3.21 mBq l"-"1 in cold springs, and between 2.5 and 15.70 mBq l"-"1 in tap water samples. "2"3"4U/"2"3"8U activity ratio is generally higher than 1 which is the equilibrium activity ratio value in closed systems. It varies in the ranges 0.79-2.11 in wells, 0.97-7.39 in hot springs, 2.53-8.30 in cold springs, and ...

Energy Technology Data Exchange (ETDEWEB)

High-pressure, lean, premixed methane/air flames are investigated experimentally to determine turbulent flame speeds (s{sub T}). The results are based on the statistical analysis of single-shot OH-PLIF images. The influences of pressure (p = 5 - 14.4 bars) and equivalence ratio ( {phi} 0.43 - 0.56) on the turbulent flame speed are discussed. The analysis reveals that s{sub T} is independent of pressure and it depends strongly on equivalence ratio. The turbulent flame speed at {phi} = 0.56 is about 3 times higher than at {phi} = 0.43 because of the higher integral reaction rate caused by the higher fuel concentration and therefore higher adiabatic flame temperature. (author)

British Library Electronic Table of Contents (United Kingdom)

The extent to which a novel wash-off process using polyamide beads removed five different types of dye from three different types of fibre was similar to that achieved using conventional aftertreatments. Whilst bead wash-off and the conventional aftertreatments were of similar duration and temperature, conventional aftertreatment employed a 10:1 or 20:1 liquor ratio whereas bead wash-off used a < 1:1 liquor ratio. As vagrant dye was adsorbed onto the bead material during wash-off, the low amount of wastewater generated contained little residual dye, thereby offering the potential of reduced environmental and cost benefits. Bead wash-off did not impair the fastness of two non-metallised acid dyes on nylon 6,6 to washing at 60 ?C.

International Nuclear Information System (INIS)

The energy dependence of the Yb and Au L_#alpha#/L_l X-ray intensity ratio, produced by 0.5 - 3.0 MeV/u Li, Be, C, N, F, and Si ion bombardment (Malhi and Gray, Phys. Rev. A 44, 7199, (1991)), measured at 90"0 relative to the beam axis, has been explained. While for light ion impact the behaviour of the alignment parameter as a function of impact velocity is dominant, for the impact of heavier ions the multiple ionization effects become important. Using Larkins' prescription in the last case, calculations have been performed, which agree well with the data over the whole energy range investigated. (Author).

International Nuclear Information System (INIS)

We have studied L x-rays from 64 MeV iodine projectile in collision with various gas targets, Z_2 #18, do not arise from selective M subshell vacancy population, has been conclusively established by the observations by Datz et al (1971) and by Saha et al (1996) that the measured intensity ratio of the Ll and L#alpha# lines, which arise because of transitions from different M subshells into the same L, subshell, does not show any periodic behaviour with Z, but stays rather constant. Differences in the measured L#beta#_1/L#alpha# intensity ratio of iodine with 7"+ and 24"+ charge states impinging on Kr target established the minor role of the electrons in the N shell of the projectile in the x-ray production mechanism. (author)

International Nuclear Information System (INIS)

Analysis of Sr-90 in milk and tap water has been conducted in New York City since 1954. The milk sample analyzed is a monthly composite of pasteurized milk purchased daily at retail stores. The monthly Sr-90 to calcium ratios for New York City since the inception of the sampling progam in 1954 through 1981 are tabulated. Samples of New York City tap water are taken daily so that by the end of the month, approximately 100 liters have been collected. Data on Sr-90 since the inception of the program are presented. The available Cs-137 data expressed as the Cs-137 to Sr-90 ratio are given. A graphical presentation of the New York City Sr-90 data is also shown.

Energy Technology Data Exchange (ETDEWEB)

This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N{sub 2} : H{sub 2}) and pulsed ratio (pulse on/off time ratio)

British Library Electronic Table of Contents (United Kingdom)

Improved radionuclide generator include a substantially insoluble salt of a radioactive parent which may be directly packed in column for subsequent elution of the daughter radionuclide. An improved 188Re generator was prepared by reacting a radioactive tungsten (188W) as parent radionuclide incorporated with aluminum chloride to obtain an insoluble radioactive aluminum tungstate matrix. The investigated matrix was characterized on the basis of the chemical composition, IR, thermal analysis and mechanical stabilities. The factors affecting the elution performance were studied such as influence of pH, molar ratio and drying temperature. From the obtained data, the molar ratio W:Al was 1.5:1 at pH?=?4, the matrix dried at 105??C for 2 h. Chromatographic and multichannel analysis has been cur...

International Nuclear Information System (INIS)

The L-shell x-ray intensity ratios I(L_#beta#)/I(L_#alpha#) and I(L_#gamma#)/I(L_a_l_p_h_a) for elements with 73 #<=# Z #<=# 83 have been measured at photon incident energies of 17.8, 25.8 and 46.9 keV. The emitted x-rays were measured with a Si(Li) detector system. The results for Re, Pt and Tl are being reported for the first time. A comparison is made of the experimental results with the calculated values obtained by using the theoretical x-ray emission rates, subshell ionisation cross sections, subshell fluorescence yields and Coster-Kronig transition probabilities. The experimental results are in reasonable agreement with the theoretical values. (author).

Energy Technology Data Exchange (ETDEWEB)

The prospects for the low-aspect-ratio (A) tokamak to fulfill the requirements of viable fusion power plants are considered relative to the present status in data and modeling. Desirable physics and design features for an attractive Blanket Test Facility and power reactors are estimated for low-A tokamaks based on calculations improved with the latest data from small pioneering experiments. While these experiments have confirmed some of the recent predictions for low-A, they also identify the remaining issues that require verification before reliable projections can be made for these deuterium-tritium applications. The results show that the low-A regime of small size, modest field, and high current offers a path complementary to the standard and high A tokamaks in developing the full potential of fusion power.