Energy Technology Data Exchange (ETDEWEB)

Oil shale resource data are provided for a 1300-square mile area around Farson, Wyoming. The data were derived from analyses of samples from 14 core holes drilled by the US Bureau of Mines and the Department of Energy, plus 4 core holes drilled by private companies. Fischer assay oil yield data for nine stratigraphic resource units are tabulated, correlated, and contoured to provide an assessment of shale oil potential in the area. Oil shale resources in the northeastern part of the Green River Basin occur in the Laney Member and the upper part of the Wilkins Peak Member of the Eocene Green River Formation. A total in-place shale oil resource of 137 billion barrels was calculated for the area. Four stratigraphic resource units have average oil yields of 12 to 20+ gallons per ton within the area of investigation, and in some parts a section up to 275 feet thick averages as much as 15.9 gallons per ton. ...

International Nuclear Information System (INIS)

The lifetime of technical constructions is determined by many factors. Technical, operational and technological aspects all help to define the term 'lifetime'. Examples from practical operation of steam turbines are considered for a discussion of 'lifetime', and methods of analysis are described. (TK/AK).

International Nuclear Information System (INIS)

We obtain x-ray absorption near-edge structures (XANES) by solving the equation of motion for the two-particle Green's function for the electron-hole pair, the Bethe-Salpeter equation (BSE), within the all-electron full-potential linearized augmented plane wave method (FPLAPW). The excited states are calculated for the Li K-edge in the insulating solids LiF, Li_2O and Li_2S, and absorption spectra are compared with independent particle results using the random phase approximation (RPA), as well as supercell calculations using the core-hole approximation within density functional theory (DFT). The binding energies of strongly bound excitations are determined in the materials, and core-exciton wavefunctions are demonstrated for LiF.

International Nuclear Information System (INIS)

... lifetime lutetium isotopes lutetium 171 lutetium 173 lutetium 175 lutetium 177

Energy Technology Data Exchange (ETDEWEB)

A continuous, subsurface Cretaceous-Tertiary boundary section, including the boundary clay within an 87 cm thick lignite, has been recovered from a core hole near Wood Mountain, Saskatchewan, Canada. The lignite-encompassed clay layer with geochemical anomaly indicates that peat deposition was continuous across the boundary. Core data indicate that, locally, a pre-boundary, conifer-dominated swamp was abruptly replaced by an angiosperm-dominated, herbaceous wetland. Sudden extermination of the dominant forest elements indicates mass kill at the level of the boundary and supports the theory of extraterrestrial impact accompanied by catastrophic destruction. Devastation of the standing vegetation may have been caused by one or more of the killing agents predicted to have accompanied impact, including freezing temperatures caused by atmospheric dust, acid rain, thermal pulse, and shock waves. There is no evidence supporting wildfires as a killing ...

Energy Technology Data Exchange (ETDEWEB)

Stargardt`s disease is inherited as an autosomal recessive condition characterized by a juvenile macular dystrophy. Genetic linkage analysis recently assigned the disease locus to chromosome 1p21-p13 with the best estimate for location of the gene near the locus D1S435. We performed linkage analysis in 34 North American families and 2 inbred families from the Kingdom of Saudi Arabia with 12 highly polymorphic markers on chromosome 1p flanking D1S435 between D1S207 and D1S223 and report significant linkage for all 12 markers with no evidence for genetic heterogeneity. Two-point linkage analysis demonstrated the Stargardt`s disease locus and D1S435 are linked with a maximum lod score of 17.17 at a recombination fraction of 1%. The markers UT851, ...

Science.gov (United States)

... Coupon 119 * 52 Probability of Survival Versus Ultimate Compressive Strength for Un-notched Laminate 1 Coupon ipn ...

International Nuclear Information System (INIS)

(Sep 1973). United Kingdom Sinanoglu, O. Luken, W. Yale Univ., New Haven,

Energy Technology Data Exchange (ETDEWEB)

A set of computer codes have been developed to produce spectral line shapes of highly stripped ions for a number of transitions in Hydrogenic, Helium-like and Lithium-like species. The choice of the transitions has been dictated largely by the laser compression experiments. The transitions of Hydrogenic species are: Lyman ..cap alpha..; Lyman ..beta..; Lyman ..gamma..; Lyman delta; Balmer ..cap alpha..; and Balmer ..beta... The transitions of Helium-like species are: 1s/sup 2/(/sup 1/S/sub 0/)-1s2p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s3p(/sup 1/P); 1s/sup 2/(/sup 1/S/sub 0/)-1s4p(/sup 1/P) and the associated ...

CERN Document Server

We report an uncertainty evaluation of an optical lattice clock based on the $^1S_0\\leftrightarrow^3P_0$ transition in the bosonic isotope $^{174}$Yb by use of magnetically induced spectroscopy. The absolute frequency of the $^1S_0\\leftrightarrow^3P_0$ transition has been determined through comparisons with optical and microwave standards at NIST. The weighted mean of the evaluations is $\

Science.gov (United States)

We demonstrated that the intensity levels and lifetimes of two-photon autofluorescences (2PAF) in human liver tissues can be exploited to diagnose hepatocellular carcinoma (HCC). Excited by an infrared femtosecond laser, we suppressed the two-photon autofluorescences of most endogenous fluorophores and made red autofluorescences more specific to particular molecules in the cryo-sectioned human livers. Using such fluorescence contrast, we found HCC tissues have reduced levels of 2PAF and longer fluorescence lifetime.

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.

International Nuclear Information System (INIS)

(1 Oct 1979). German Democratic Republic Alekseeva, OK Onishchuk, VA

International Nuclear Information System (INIS)

... gamma cascades kev range 10-100 lifetime lutetium 171 lutetium 173 lutetium

Energy Technology Data Exchange (ETDEWEB)

Lifetimes have been measured for a dipole band in {sup 139}Sm using DSAM. The deduced B(M1) and B(E2) values as well as B(M1)/B(E2) ratios are compared with calculations in the framework of the TAC (Tilted Axis Cranking) and SPAC (Shears mechanism with Principal Axis Cranking) models. The dipole band in {sup 139}Sm can be considered as a magnetic rotational band with a prolate or triaxial nuclear deformation. (orig.)

Science.gov (United States)

The defect-induced electron lifetime and energy-gap anisotropy effects on the T/sub c/ of the A-15 compounds are examined. A self-consistent model calculation demonstrates that the various defect dependences of T/sub c/ can be qualitatively understood in terms of the electron-lifetime effect.

CERN Document Server

I review findings of various research groups regarding perturbative heterotic string model building in the last 12 months. Attention is given to recent studies of extra U(1)'s and local discrete symmetries (LDS's) in generic string models. Issues covered include the role of U(1)'s and LDS's in limiting proton decay, developments in classification of models containing anomalous U(1), and possible complications resulting from kinetic mixing between observable and hidden sector U(1)'s. Additionally, recent string-derived and string-inspired models are briefly reviewed. Talk Presented at SUSY '97.

Science.gov (United States)

Page 1. S~Infantry Behind the Lines- Still A Viable Concept? A Monograph by Major Mike McMahon Infantry 4T-' School ...

International Nuclear Information System (INIS)

The g factors of the 2_1"+ states in sup(84,86,88)Sr have been deduced using the thin-foil transient field technique with the field calibration of the Rutgers group. The values are g("8"4Sr)= + 0.419(47), g("8"6Sr)= + 0.273(50) and g("8"8Sr)= + 1.15(17). The mean lifetimes of the 2_1"+ states in sup(86,88)Sr were determined by the Doppler-shift attenuation method to be 2.10(22) ps and 0.219(23) ps respectively. The g factor and lifetime results are compared with shell model and interacting boson model predictions. (author).

International Nuclear Information System (INIS)

Alloy 800 has been used for steam generator (SG) tubing for more than 30 years, primarily in CANDU reactors worldwide and in reactors in Germany. Extensive laboratory testing and in-service experience suggest that the Alloy 800 tubing has excellent resistance to corrosion-related degradation under appropriate operating conditions. In planning refurbishment of nuclear plants stations, a key concern is the longevity of existing SGs up to the 60-year lifetime of the refurbished plant. The paper reviews an existing methodology based on the concept of the improvement factor, and refines its estimation based on data specific to CANDU operating conditions. The paper presents a more advanced Bayesian probabilistic approach to estimate the degradation free lifetime distribution of Alloy 800 tubing, which is used to quantify the probability of degradation during the service life and to evaluate the impact of potential occurrences of degradation on ...

Energy Technology Data Exchange (ETDEWEB)

The g factors of the 2/sub 1//sup +/ states in sup(84,86,88)Sr have been deduced using the thin-foil transient field technique with the field calibration of the Rutgers group. The values are g(/sup 84/Sr)= + 0.419(47), g(/sup 86/Sr)= + 0.273(50) and g(/sup 88/Sr)= + 1.15(17). The mean lifetimes of the 2/sub 1//sup +/ states in sup(86,88)Sr were determined by the Doppler-shift attenuation method to be 2.10(22) ps and 0.219(23) ps respectively. The g factor and lifetime results are compared with shell model and interacting boson model predictions.

Energy Technology Data Exchange (ETDEWEB)

Knowledge, assessment and understanding of phenomena caused by ageing, together with systematic utilization and extension of the technical life-time of components and systems, are of critical importance to the safety and economy of electricity generation in nuclear power stations. Economic use can be optimized by integrated ageing and life-time management; it can also be used to improve performance characteristics. (orig.) [Deutsch] Fuer die Sicherheit und Wirtschaftlichkeit der Stromerzeugung in Kernkraftwerken sind die Kenntnis, Bewertung und Beherrschung alterungsbedingter Phaenomene und systematische Ausnutzung bzw. Verlaengerung der technischen Lebensdauer der Komponenten und Systeme von zentraler Bedeutung. Durch ganzheitliches Alterungs- und Lebensdauermanagement, das auch auf die Verbesserung von Leistungsmerkmalen abzielt, kann der wirtschaftliche Nutzen optimiert werden. (orig.)

International Nuclear Information System (INIS)

Alloy 800 has been used for steam generator (SG) tubing for more than 30 years, primarily in CANDU reactors and in reactors in Germany. Extensive laboratory testing and in-service experience suggest that the Alloy 800 tubing has excellent resistance to corrosion-related degradation under specified and appropriate operating conditions. In planning refurbishment of CANDU stations, a key concern is the longevity of existing SGs up to the 60 year lifetime of the refurbished plant. The paper reviews an existing methodology based on the concept of the improvement factor, and estimates it based on experimental data specific to CANDU operating conditions. The paper presents a more advanced probabilistic approach to estimate the degradation free lifetime distribution of Alloy 800 tubing, which is used to quantify the probability of degradation during the service life and to evaluate the impact of potential occurrences of degradation on reliability of SG ...

Energy Technology Data Exchange (ETDEWEB)

Stargardt disease (STGD) and fundus flavimaculatus are infrequent autosomal recessive conditions characterized by a juvenile macular dystrophy and variable degrees of peripheral retinal changes. Linkage analysis performed in 47 STGD/fundus flavimaculatus families demonstrated significant linkage to 13 polymorphic DNA markers on chromosome 1p. The maximum combined two-point lod score was 32.7 (maximum recombination fraction [{theta}{sub max}] = .006) with the polymorphic marker D1S188. Our data demonstrate that STGD and fundus flavimaculatus are the same disorder clinically and genetically and provide further evidence for genetic homogeneity of this phenotype. Analysis of recombination on disease chromosomes placed the STGD gene within a 4-cM interval between markers D1S435 and D1S236. A physical map was constructed of a YAC contig flanking STGD, from markers ...

Energy Technology Data Exchange (ETDEWEB)

The current status of cosmological observations is presented; and the light curves and radiation spectra from supernova SN1987A are used in comparison between expected and observed universal nucleosynthesis and star evolution data./aip/.

UK PubMed Central (United Kingdom)

BackgroundSmall laboratory fish share many anatomical and histological characteristics with other vertebrates, yet can be maintained in large numbers at low cost for lifetime studies....Full Text Available

UK PubMed Central (United Kingdom)

Polyandrous mating is common, but the benefits for females of polyandry remain controversial. To test whether mating with multiple males affects female fitness, we compared lifetime components of fitness...Full Text Available

International Nuclear Information System (INIS)

GaN and Al_1_-_xGa_xN films were grown by the method of ECR-MBE. Absorption constants as a function of wavelength were determined from transmission measurements. Photoconducting detectors were fabricated from these films and characterized in terms of their spectral response and photoconductive gain. Mobility-lifetime products were determined from the measurement of photoconductive gain. The resistivity and mobility-lifetime products of the films were varied from 10--10"9 ohm-cm and 10"-"3--10"-"8 cm"2/V respectively by changing the microwave power in the ECR discharge from 20--60 watts. The change in the mobility-lifetime product is attributed to change in the lifetimes of the photogenerated carriers. This assumption is supported by direct measurement of detector response times. Finally, the authors report for the first time, the detection of alpha particles using GaN detectors.

Energy Technology Data Exchange (ETDEWEB)

Minority-carrier lifetime damage coefficients for 1 MeV electron, 3 MeV proton, and 6 MeV alpha particle irradiation of n-type (4.5{times}10{sup 15} and 1.3{times}10{sup 17}cm{sup {minus}3}) and p-type (2.5{times}10{sup 17}cm{sup {minus}3}) InP have been measured using time-resolved photoluminescence. These values are relatively insensitive to carrier type and show a slight increase with increasing carrier concentration. Evidence of comparable electron and hole capture lifetimes is found for the dominant recombination defect. The effect of 3 MeV proton and 6 MeV alpha particles relative to 1 MeV electrons is an increase in the lifetime damage coefficient by factors of about 10{sup 4} and 10{sup 5}, respectively. {copyright} {ital 1997 American Institute of Physics.}

International Nuclear Information System (INIS)

Radiation defects produced by helium implantation were used to shape profiles of palladium (Pd) and platinum (Pt) atoms in-diffusing (for 20 min at temperatures 600-800 deg. C) either from surface silicide (Pd_2Si, PtSi) or implanted layers. Results show that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centers - the acceptor level of substitutional Pd (E _c - 0.22 eV) or Pt (E _c - 0.23 eV). While optimum conditions for Pt in-diffusion are about 700 deg. C, Pd gives the best results already at lower temperatures (600 deg. C) where it also exhibits higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by Pd and Pt, exhibited similar trade-off between the static and ...

Science.gov (United States)

Spontaneous radiation by an atom in a Rydberg state is inhibited by use of parallel conducting planes to eliminate the vacuum modes at the transition frequency. Spontaneous radiation emission is observed to turn off abruptly at the cutoff frequency of the waveguidelike structure, and the natural lifetime is measured to increase by a factor of at least 20.

UK PubMed Central (United Kingdom)

Hematopoietic stem cells replenish all the cells of the blood throughout the lifetime of an animal. Although thousands of stem cells reside in the bone marrow, only a few contribute to blood production...Full Text Available

Science.gov (United States)

To estimate the waste management needs of a fusion power reactor, a scheme for handling radioactive waste from a fusion plant has been devised. The handling scheme proceeds with radioactive waste, primarily from blanket replacement, being stored on-site; waste in cooled and shielded casks is then isolated off-site; finally, the materials are recycled. Using activities and component lifetimes supplied by designers, several conceptual fusion power reactors have been analyzed and their waste streams compared to fission reactors with regard to total activity, specific activity, and lifetimes of activity.

Energy Technology Data Exchange (ETDEWEB)

Lifetimes have been measured in the {pi}h{sub 9/2} (yrast) and {pi}i{sub 13/2} (excited) bands in the nuclei {sup 181}Ir and {sup 187}Au using the Recoil Distance Method (RDM). The results clearly indicate that the {pi}i{sub 13/2} band exhibits an increased deformation over the {pi}h{sub 9/2} band, in keeping with the premise that the delayed crossing in this band is due to enhanced quadrupole deformation. (author). 3 refs, 1 fig, 2 tab.

Energy Technology Data Exchange (ETDEWEB)

Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N-curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle-fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonitrides or Aluminium Oxides. A model was developed to describe the influence of the magnitude of these inclusions on the lifetime. A weakest link model, using the statistical distribution of inclusions and surface flaws, was used to describe the fatigue limit. (orig.)

International Nuclear Information System (INIS)

In the scope of the nuclear plants lifetime study, the behavior of the cooling towers is discussed. The main geometrical characteristics of the cooling towers in the French nuclear power plants, are presented. The surveyance program, the risks of accident, the research and development actions are considered. The results of the investigations of the cooling tower structure show that it is a multidiciplinary problem and needs the development of experimental and theoretical methods. Concerning the regenerators, the surveyance actions under operating conditions, the accelerated aging tests, and some aspects of the mechanical resistance, are underlined. It is shown that mainly the creep tests will allow the lifetime estimation of the materials developed for the regenerators.

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.

CERN Document Server

In the framework of the $^3P_0$ meson decay model, the strong decays of the $3 ^1S_0$ and $4 ^1S_0$ $s\\bar{s}$ states are investigated. It is found that in the presence of the initial state mass being 2.24 GeV, the total widths of the $3 ^1S_0$ and $4 ^1S_0$ $s\\bar{s}$ states are about 438 MeV and 125 MeV, respectively. Also, when the initial state mass varies from 2220 to 2400 MeV, the total width of the $4 ^1S_0$ $s\\bar{s}$ state changes from about 100 MeV to 132 MeV, while the total width of the $3 ^1S_0$ $s\\bar{s}$ changes from about 400 MeV to 594 MeV. A comparison of the predicted widths and the experimental result of $(0.19\\pm 0.03^{+0.04}_{-0.06})$ GeV, the width of the $\\eta(2225)$ with a mass of ...

UK PubMed Central (United Kingdom)

BackgroundA large fraction of the human genome is attributable to L1 retrotransposon sequences. Not only do L1s themselves make up a significant portion of the genome, but L1-encoded...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The objective of the investigation was to study the feasibility of applying continuous casting steel 100Cr6 (SAE 52100) for bearing balls. It was found that two of three continuous casted steel batches have longer or at least similar rolling contact fatigue lifetimes compared to one ingot casted batch. For one of the continuous casted batches, the rolling contact fatigue lifetime was 30% less. The micro- and macrostructure and the residual stresses below the surface of the balls were comparable. There is also no obvious difference between the four batches in the metallurgical parameters like contents of oxygen, titanium and sulfur as well as in the distribution of carbides and their network. The reason for the shorter lifetime of one batch finally was found to be due not to the continuous casting process itself. There was a difference in the cross section of the different casting moulds, and by this in the speed of ...

International Nuclear Information System (INIS)

The divertor 'Large Project' was conceived with the aim of demonstrating the feasibility of meeting the lifetime requirements by employing the candidate armor materials of beryllium, tungsten (W) and carbon-fiber-composite (CFC). At the start, there existed only limited experience with constructing water-cooled high heat flux armored components for tokamaks. To this was added the complication posed by the need to use a silver-free joining technique that avoids the transmutation of n-irradiated silver to cadmium. The research project involving the four Home Teams (HTs) has focused on the design, development, manufacture and testing of full-scale Plasma Facing Components (PFCs) suitable for ITER. The task addressed all the issues facing ITER divertor design, such as providing adequate armor erosion lifetime, meeting the required armor-heat sink joint lifetime and heat sink fatigue life, sustaining thermal-hydraulic and ...

Energy Technology Data Exchange (ETDEWEB)

Ga{sub 0.6}In{sub 0.4}P/(Al{sub 0.8}Ga{sub 0.2}){sub 0.4}In{sub 0.6}P strain-compensated multiple quantum wells (SCMQW) and Ga{sub 0.5}In{sub 0.5}P/(Al{sub 0.4}Ga{sub 0.6}){sub 0.5}In{sub 0.5}P unstrained MQW were grown by MOVPE to investigate the shift of photoluminescence (PL) peak wavelength and the carrier lifetime caused by strain effect in SCMQW. The PL peaks of SCMQW and unstrained MQW were 608 and 628 nm, respectively. From the rocking curve of SCMQW, it indicated that the active layers of SCMQW were not zero net strain. The residual strain caused the emission intensity of SCMQW to be about four times weaker than that of unstrained MQW. The carrier lifetimes of SCMQW and unstrained MQW were measured to be 3 and 6.02 ns, respectively. It was conjectured that the residual strain in SCMQW induced a decrease in the carrier lifetime by a factor of two with respect to that of unstrained MQW.

Energy Technology Data Exchange (ETDEWEB)

The performance and lifetime of energy storage in batteries are an important part of many renewable based energy systems. Not only do batteries impact on the system performance but they are also a significant expenditure when considering the whole life cycle costs. Poor prediction of lifetime can, therefore, lead to uncertainty in the viability of the system in the long term. This report details the work undertaken to investigate and develop two different battery life prediction methodologies with specific reference to their use in hybrid renewable energy systems. Alongside this, results from battery tests designed to exercise batteries in similar modes to those that they experience in hybrid systems have also been analysed. These have yielded battery specific parameters for use in the prediction software and the first results in the validation process of the software are also given. This work has been part of the European Union Benchmarking ...

International Nuclear Information System (INIS)

Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 #approx# 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from simultaneous aging test, while CSM lifetime ...

Energy Technology Data Exchange (ETDEWEB)

The rate coefficients for the reactions of OH radical with CH3Br and CH2Br2 were measured as functions of temperature using the laser photolysis - laser induced fluorescence method. This data was incorporated into a semiempirical model (Solomon et al., 1992) and a 2D model to calculate the steady-state ozone depletion potentials (ODP) and atmospheri lifetimes, tau, with greatly improved accuracy as compared to earlier studies. The calculated ODPs and tau are 0.65 and 1.7 years and 0.17 and 0.41 years for CH3Br and CH2Br2, respectively, using the semiempirical model. These lifetimes agree well with those calculated using a 2D model. This study better quantifies the ODPs and tau of these species which are needed inputs for discussion of possible regulation of human emissions currently under international considerations. 29 refs.

CERN Document Server

We study the temporal evolution of coronal loops using data from the Solar X-ray Imager (SXI) on board of GOES-12. This instrument allows us to follow in detail the full lifetime of coronal loops. The observed light curves suggest three somewhat distinct evolutionary phases: rise, main, and decay. The durations and characteristic timescales of these phases are much longer than a cooling time and indicate that the loop-averaged heating rate increases slowly, reaches a maintenance level, and then decreases slowly. This suggests that a single heating mechanism operates for the entire lifetime of the loop. For monolithic loops, the loop-averaged heating rate is the intrinsic energy release rate of the heating mechanism. For loops that are bundles of impulsively heated strands, it is an indication of the frequency of occurrence of individual heating events, or nanoflares. We show that the timescale of the loop-averaged heating rate is proportional ...

Energy Technology Data Exchange (ETDEWEB)

The divertor collector plate in the INTOR reactor will be subjected to high heat, particle, and neutron fluxes, making it the most severely damaged torus component. The collector plate is composed of a protection plate, which is directly exposed to the particle flux, and a heat sink which provides support for the protection plate and carries the water coolant. The high-Z refractory metals have been considered for use as the protection plate material, and austenitic stainless steels and copper alloys have been considered as the heat sink material. Tungsten and Type 316 stainless steels have been selected for the protection plate and heat sink, respectively. The protection plate has a sputtering lifetime of 1.75 y at a 50% duty factor, while the heat sink is expected to last the lifetime of the reactor.

Energy Technology Data Exchange (ETDEWEB)

Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle fatigue, crack initiation was most likely caused by inclusions like Titanium Carbon nitrides or Aluminium Oxides. A micro mechanical model for the crack initiation by inclusions was developed. Another model was developed to describe the influence of these inclusions on the lifetime. A weakest-link model, using the statistical distribution of inclusions and surface flaws, was used to describe the endurance limit. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Purpose - Burr distribution has been proved to be a useful failure model. It can assume different shapes which allow it to be a good fit for various lifetimes data. Hybrid censoring is an important way of generating lifetimes data. The purpose of this paper is to estimate an unknown parameter of the Burr type XII distribution when data are hybrid censored. Design/methodology/approach - The problem is dealt with through both the classical and Bayesian point of view. Specifically, the methods of estimation used to tackle the problem are maximum likelihood estimation method and Bayesian method. Empirical Bayesian approach is also considered. The performance of all estimates is compared through their mean square error values. The paper employs Monte Carlo simulation to evaluate the mean square...

Energy Technology Data Exchange (ETDEWEB)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of [sup 87]Mo are studied in detail and explained by the evolution of the [gamma]-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N [>=] 47 for the spherical shape of the Mo isotopes. (orig.)

Energy Technology Data Exchange (ETDEWEB)

This report describes the test of a dynamic phase compensation unit for a wind turbine with directly connected induction generators. The compensation unit is based on thyristor switched capacitors, where conventional wind turbine compensations use mechanical contactors to switch the capacitors. The influence on power quality analysed, and influence on component lifetime is discussed. Besides, simulation models in Matlab/Simulink are presented, including a flicker meter model. (au)

Environmental Research Database

DescriptionIn young pigs the post-weaning period is generally characterised by a marked reduction in voluntary feed intake, poor growth and development, and diarrhoea. The associated reduction in digestive and absorptive capacity of the gastrointestinal tract decreases the overall efficiency of nutrient capture and utilisation, thereby causing an increase in nutrient loading to the environment. The reduction in digestive and absorptive efficiency after weaning has implications for lifetime performance be [continued...

International Nuclear Information System (INIS)

The intensity of luminescence from the "2E state of Cr(bpy)_3"3"+ (bpy = 2, 2'-bipyridine) is lower in D_2O, although the "2E lifetime is unchanged, indicating that the "4T_2 (precursor to "2E) is sensitive to the isotopic nature of the solvent. A photophysical mechanism is proposed for Cr(NN)_3"3"+ complexes.

International Nuclear Information System (INIS)

An apparatus allowing the photoexcitation of barium atomic beam over its whole surface is described. This photoexcitation is achieved by another barium spectrum emitted up steam of the beam by a cathodic out-flow produced at the exit oven. The fluorescence spectrum is studied in detail as well as the influence of different parameters, such as oven temperature, current intensity of the outflow, and excitation depth. A calculation shows how to determine Einstein coefficient, oscillator strengths and atomic lifetimes from our experimental measurements.

Science.gov (United States)

Results are presented of experiments on partial discharge in liquid nitrogen, including insulation breakdown characteristics of liquid nitrogen, partial discharge characteristics of composite insulation systems, lifetime of polymer films, impulse breakdown of polymer films in liquid nitrogen, etc. The partial discharge characteristics of liquid nitrogen are examined with increasing liquid-nitrogen pressure. It is concluded that a composite insulation structure of polymer film and liquid nitrogen can be used as effective electrical insulators at cryogenic temperatures.

Energy Technology Data Exchange (ETDEWEB)

Frequency response measurements are used to determine the carrier lifetime of 1.3-..mu..m InGaAsP buried heterostructure lasers between 1 mA and threshold. The data confirm previous results on the radiative and Auger recombination coefficients and reveal the presence of a nonradiative current which dominates at low currents and contributes 4 mA at threshold.

Energy Technology Data Exchange (ETDEWEB)

A research report presents the basic data required when designing a building with minimal environmental impacts. Topics covered include the energy consumption of building elements during their lifetime, the environmental implications linked to the extraction and processing of building material and the energy consumed in buildings by the occupants. (UK)

Science.gov (United States)

Erosion is the main contributing factor to the decrease in lifetime of gun barrels. The precision, muzzle velocity and fire range deteriorate when the surface inside the gun tube is eroded. This study deals with gun barrel material, what happens in the ba...

Environmental Research Database

DescriptionThis application is a request for Bridge Link funds to support studies in order to develop a full proposal under the Link Sustainable Livestock Scheme in collaboration with Dr Nigel Scollan of IGER. The hypothesis being examined is that the poor performance of some ruminants is due to poor nutrition at strategic time points during the animal's development. The initial hypothesis will be tested in sheep and the results from this will be used to develop the full proposal. Excessive fat in ruminan [continued...

International Nuclear Information System (INIS)

Results of an augmented-plane-wave calculation of the positron lifetime and the angular-correlation curves for aluminum, both in the vacancy-free crystal and in the crystal with a vacancy, are presented. The environment of the vacancy was simulated by a face-centered-cubic supercell with a volume 27 times that of the standard primitive unit cell of the Al lattice. The calculated positron-vacancy binding energy is 3.36 eV at room temperature. The temperature dependences of the trapping potential, the positron-vacancy binding energy, and the positron lifetime both in the Bloch state and in the vacancy-trapped state, associated only with the static thermal expansion of the lattice, have been calculated. It is found that the fractional increase in positron lifetime in the Bloch state is only approx.80% of the fractional increase in the volume of the lattice. The lifetime in the vacancy-trapped state is also ...

International Nuclear Information System (INIS)

A simple model is described to simulate kinetic processes in dielectric barrier discharges for O_2/NO_x mixtures. A threshold of ozone production found experimentally is confirmed by the calculations of this modeling, and the underlying chemical reaction mechanisms are discussed. It is also found that the effects of diffusion processes in the period of the lifetime of O atoms are not important to micro-discharge channels with a large radius, i.e. larger than 150 #mu#m

Energy Technology Data Exchange (ETDEWEB)

The isotope shifts of the levels 5p/sup 2/ /sup 1/D/sub 2/, /sup 1/S/sub 0/ and 5sns /sup 1/S/sub 0/(n = 7,8) of strontium have been measured between the isotopes 84, 86, 87 and 88 in two-photon transitions from the ground state, using two lasers with different wavelengths. These levels occur below the beginning of the Rydberg series, and are known to exhibit very strong configuration mixing. Mass and field isotope shifts are calculated ab initio by means of the MCHF method for these levels and 5s4d /sup 1/D2, 5s6s /sup 1/S/sub 0/. The qualitative agreement between theory and experiment confirms the necessity of taking into account the mixing (up to 50%) with both the 5p/sup 2/ and 4d/sup 2/ perturbers in the wavefunction expansions.

Energy Technology Data Exchange (ETDEWEB)

X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) have been conducted on a new fuel cell electrocatalytic material based on a highly porous carbonized polyacrylonitrile (PAN) microcellular foam with very low platinum loading ({approximately}13 to 23 {micro}g/cm{sup 2}). TEM images of this material clearly show the existence of nanometer size platinum particles which are homogeneously distributed in the highly porous carbonized PAN matrix. An XPS study of Pt-loaded PAN indicates that C 1s, O 1s, and N 1s peaks shift to lower binding energies, compared to virgin PAN. It was concluded that special metal-support interaction exists, through the formation of a charge-transfer complex between platinum and pyridine-type nitrogen atoms of PAN support. This interaction leads to the enhancement of the catalytic activity, and the improvement ...

British Library Electronic Table of Contents (United Kingdom)

Mono- and disubstituted novel derivatives of the heptaene nystatin analog 28,29-didehydronystatin A1 (S44HP, 1) were obtained by chemical modification of the exocyclic C-16 carboxyl and/or an amino group of mycosamine moiety. The strategy of preparation of mono- and double-modified polyene macrolides was based on the use of intermediate hydrophobic N-Fmoc (9-fluorenylmethoxycarbonyl) derivatives that facilitated the procedures of isolation and purification of new compounds. The antifungal activity of the new derivatives was first tested in vitro against yeasts and filamentous fungi, allowing the selection of the most active compounds that were subsequently tested for acute toxicity in mice. 2-(N,N-dimethylamino)ethylamide of 1 (2) and 2-(N,N-dimethylamino)ethylamide of N-fructopyranosyl-28...

CERN Document Server

We have conducted a systematic investigation of the origin and underlying physics of the line--line and line--continuum correlations of AGNs, particularly the Baldwin effect. Based on the homogeneous sample of Seyfert 1s and QSOs in the SDSS DR4, we find the origin of all the emission-line regularities is Eddington ratio (L/Ledd). The essential physics is that L/Ledd regulates the distributions of the properties (particularly column density) of the clouds bound in the line-emitting region.

UK PubMed Central (United Kingdom)

P2X1 receptors for ATP contribute to signalling in a variety of cell types and following stimulation undergo rapid desensitisation (within 1 s), and require ∼5 min to recover. In HEK293 cells...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Calculations of total and angle-differential excitation cross sections for the electron impact excitation of lithium-like iron were performed with the R-matrix formulation. The alignments of the excited states 1s{sup 2}np {sup 2}P{sub 3/2} are also presented for n=3 and 4 along with the angular photon distribution from these states to the ground state. Relativistic effects were included in the present calculations by the Breit-Pauli Hamiltonian.

International Nuclear Information System (INIS)

Measurements of gamma-ray spectra, following the thermal neutron fission of "2"3"5U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions ...

CERN Document Server

A debris disk is a constituent of any planetary system surrounding a main sequence star. We study whether close stellar encounters can disrupt and strip a debris disk of its planetesimals in the expanding open cluster of its birth. Such stripping would affect the dust production and hence detectability of the disk. We tabulated the fractions of planetesimals stripped off during stellar flybys of miss distances between 100 and 1000 AU and for several mass ratios of the central to passing stars. We then estimated the numbers of close stellar encounters over the lifetime of several expanding open clusters characterized by their initial star densities. We found that a standard disk, with inner and outer radii of 40 and 100 AU, suffers no loss of planetesimals around a star born in a common embedded cluster with star density 20 000 pc^-3. In this environment, a disk loses >97% of its planetesimals around an M-dwarf, >63% around a solar-type star, and >42% ...

International Nuclear Information System (INIS)

Analyses of the roles of cement-based barriers in radioactive waste isolation show that models used to estimate their characteristics during the lifetime of the repository must consider the alteration of material properties with time due to degradation processes. Reinforced concrete barriers at repositories shall be designed in such manner that they fulfil besides isolative capabilities also the required functions of mechanical resistance and stability. Key elements of safety evaluation are mainly the correct selection of materials for mineral composites with cement binder (cements, aggregates, mineral additives and chemical admixtures) and their design, execution of construction works and production of precast concrete containers (continuous casting of concrete - no cold joints, limited number of construction joints, proper placing and consolidation, finishing and curing), strict control of used materials and inspection of works, as well as investigation after the ...

Energy Technology Data Exchange (ETDEWEB)

This proceedings is the compilation of papers presented at the ninth PV Performance and Reliability Workshop held at the Sheraton Denver West Hotel on September 4--6, 1996. This years workshop included presentations from 25 speakers and had over 100 attendees. All of the presentations that were given are included in this proceedings. Topics of the papers included: defining service lifetime and developing models for PV module lifetime; examining and determining failure and degradation mechanisms in PV modules; combining IEEE/IEC/UL testing procedures; AC module performance and reliability testing; inverter reliability/qualification testing; standardization of utility interconnect requirements for PV systems; need activities to separate variables by testing individual components of PV systems (e.g. cells, modules, batteries, inverters,charge controllers) for individual reliability and then test them in actual system configurations; more results ...

DEFF Research Database (Denmark)

OBJECTIVES: The authors examine the rationale and efficacy of pre-travel hepatitis B immunization strategies based on itinerary and presumed on-travel risk behaviour. METHODS: A large survey among 26,640 Danes survey provided data on journey lengths and destinations, immunization coverage, risk behaviour and knowledge. RESULTS: The estimated cumulative lifetime stay in endemic areas outside Europe is 4.3 months. The majority of risk situations are involuntary and unforeseeable. The majority of risk situations occur on short-term journeys. 5% nonimmune and 5% short-term travellers experienced at least one risk situation such as injections/operations/tattoos on their journey. The level of knowledge of hepatitis A and B is low. CONCLUSIONS: The rationale and efficacy of current immunization strategies are challenged. Based on the results presented here and the availability of vaccines with long-lasting coverage, the authors find that recommendations of immunization ...

International Nuclear Information System (INIS)

Awaiting new data from RERF, an attempt was made to estimate the somatic risks of low doses of radiation for members of the German public. The new estimate follows closely the approach used in deriving the values published in the NIH Radioepidemiological Tables. The lifetime risk factors thus calculated are significantly larger than the estimates presented in ICRP Report 26 and are consistent with estimates recently made in the ongoing reactor safety study of NUREG. The increase in lifetime risks is mainly due to the introduction of a new time projection model which appears to be more consistent with the epidemiological data for many late effect end points than the constant absolute risk model previously employed. Results from a study in which epidemiological data were stochastically simulated with a computer indicate that the shapes of actual dose effect curves might be significantly more influenced by pure chance than by the dose dependency ...

Energy Technology Data Exchange (ETDEWEB)

We duscuss a resonant microwave trap for neutral atoms. Because of the long spontaneous radiation time this trap is remarkably different from the optical trap. It also has advantages over static magnetic traps that trap the excited spin state of the lowest electronic level, in that atoms predominantly in the spin ground state can be trapped. We analyze the relaxation-ejection lifetime of atoms in such a trap using the formalism of dressed atomic states. Results are appliedi to atomic hydrogen and the possibility of Bose-Einstein condensation is considered.

CERN Document Server

The intrinsic decay rate of orthopositronium formed in SiO/sub 2/ powder is measured using the direct 2 gamma correction method such that the time dependence of the pick-off annihilation rate is precisely determined. The decay rate of orthopositronium is found to be 7.0396+or-0.0012(stat.)+or-0.0011(sys.)/ mu s/sup -1/, which is consistent with our previous measurements with about twice the accuracy. Results agree well with the O( alpha /sup 2/) QED prediction, and also with a result reported very recently using nanoporous film.

Energy Technology Data Exchange (ETDEWEB)

One of the major scientific and technological challenges for the production of flexible organic electronic devices is the device protection against atmospheric molecule permeation, which causes corrosion reducing its operation and lifetime. In this work, Spectroscopic Ellipsometry has been implemented to investigate the influence of silicon dioxide nanoparticles on the optical properties of hybrid polymers. The spectra analysis revealed valuable information about the electronic and vibrational response as well as the cross-linking mechanisms of these materials. The correlation of the optical properties with the synthesis parameters and the barrier response will contribute towards their optimization in order to be used as high barrier coatings for flexible organic electronics applications.

Energy Technology Data Exchange (ETDEWEB)

The temperature and pressure dependence of the mobilities of negative charges injected into liquid hydrogen and deuterium have been measured. The authors propose the existence of two types of charge carriers in liquid parahydrogen. One is a bubble with an electron inside while the other has higher mobility. Relaxation of the current through liquid hydrogen was observed. It is suggested that in liquid and solid hydrogen under {beta}-irradiation neutral complexes are created which can trap the negative charges and have a lifetime of about 10 hours. 6 refs., 5 figs.

International Nuclear Information System (INIS)

The ANDRA, the French national agency of radioactive wastes, is organizing today the information needs of tomorrow. The aim is to allow the future generations to have access to the knowledge of the existence of subsurface radioactive waste facilities and to understand the context and technologies of such facilities. The storage of this information is made on 'permanent paper', a high resistant paper with a lifetime of 600 to 1000 years. An updating of these data is made every 5 years for each waste disposal center. Another project, still in progress, concerns the memory management of deep geologic waste disposal facilities for which the time scale to be considered is of the order of millennia. (J.S.)

International Nuclear Information System (INIS)

The lifetime of the circulating electron beam in the Naval Research Laboratory modified betatron has been increased by more than 2 orders of magnitude with the addition of strong focusing windings to the device. The injected beam consistently spirals from the injector to the minor axis and is trapped. The #approx#0.5-kA trapped electron ring has been accelerated above 10 MeV from the injection energy of 0.5 to 0.6 MeV. The beam acceleration has been confirmed not only by the x-ray attenuation technique but also with the detection of photoneutrons.

Energy Technology Data Exchange (ETDEWEB)

The design of High-Voltage, Direct-Current transmission cables insulated with oil-impregnated cellulose paper is constrained by the maximum temperature and the maximum steady-state and transient stresses (voltage gradients) that the cable insulation can reliably withstand over the desired operating lifetime. Because the electrical stresses in the insulation are related in a very complex fashion to temperature, applied voltage and cable geometry, iterative techniques are required to compute the values of these stresses. Digital computers are ideally suited for these iterative techniques. This paper presents the principal equations and logic needed to develop suitable computer programs.

Science.gov (United States)

We have demonstrated fluorescence resonance energy transfer (FRET) between lanthanide-ion doped oxide nanoparticles acting as donors and organic acceptor molecules (Cy5). Due to the long nanoparticle lifetime and the large Stokes shift between nanoparticle absorption and emission, unambiguous and precise FRET measurements can be performed despite the presence of large free acceptor oncentrations. We determined FRET efficiencies as a function of Cy5 concentration which are in very good agreement with a multiple acceptor-multiple donor calculation.

Energy Technology Data Exchange (ETDEWEB)

We provide two examples to illustrate how electronic structure calculations contribute to our understanding of vacancies and their role in determining material properties. Diffusion and elctromigration in aluminium are known to depend strongly on vacancies. Electronic structure calculations show that the vacancy-impurity interaction oscillates with distance, and this leads to an explanation for both the increased elctromigration resistance and the slow impurity diffusion for copper in aluminium. Calculations of vacancies in plutonium have been used in conjunction with positron annihilation lifetime measurements to identify the presence of helium-filled vacanies. Helium stabilization of vacancies can provide the precursors for subsequent vacancy-related changes in materials properties.

Energy Technology Data Exchange (ETDEWEB)

The multicell proportional chambers at the backing calorimeter of the ZEUS experiment at the storage ring HERA are supplied with a gas mixture of Ar/CO[sub 2] by an open gas system. Flow proportional counters with the build-up [sup 55]Fe sources are used as gas system monitoring detectors. The ZEUS experiment is planned to collect data for about 10 years. Therefore, the lifetime of the Ar/CO[sub 2] mixture should be known. In this paper, the results of laboratory tests and preliminary measurements of the aging effects for monitoring counters are presented. ((orig.))

Energy Technology Data Exchange (ETDEWEB)

The competitiveness of a new nuclear plant vs. a new oil or gas fired combined cycle plant or a coal fired plant in East-Asia, is reviewed in the paper. Both the nuclear and the fossil fired plants are evaluated as either utility financed or independent power producer (IPP) financed. Two types of advanced light water reactors (ALWRs) are considered in this paper, namely evolutionary ALWRs (1200 MWe size) and passive ALWRs (600 MWe class). A range of capital and total generation costs for each plant type is reported here. The comparison centers on three elements of overall competitiveness: generation costs, hard currency requirements, and employment requirements. Each of these aspects is considered perspective. Year-by-Year generation cost history over the plant lifetime is shown in some cases. It is found here that a utility financed evolutionary and passive ALWRs are broadly competitive with an IPP financed gas fired combined cycle plant and are more economic than ...

Energy Technology Data Exchange (ETDEWEB)

The project has been developing Yttria Stabilized Zirconia (YSZ)-Alumina Composites as an electrolyte of a self-support type planar Solid Oxide Fuel Cell (SOFC) from the following points of view: a path of alumina particles with high thermal conductivity can be designed as an electrolyte sheet; there are some possibilities that the electrolyte can be enhanced in mechanical strength. As previously reported, these composite materials have higher mechanical strength and better thermal shock resistance than those of YSZ. These composites containing 0-30 wt% of Al[sub 2]O[sub 3] were measured by AC impedance method at temperatures of 250-1,000[degree]C. Electrical conductivities of 8YSZ without Al[sub 2]O[sub 3] and a composite consisting of 80 wt% YSZ and 20 wt%Al[sub 2]O[sub 3] as sintered samples were 1.2 x 10[sup -1]S/cm and 1.0 x 10[sup -1]S/cm respectively at 1,000[degree]C. The composite containing 20 ...

Science.gov (United States)

Cross sections for excitation induced by electron collision between low-lying 1s{sup 2}2s{sup 2}2p{sup 5} and 1s{sup 2}2s2p{sup 6} states of f-like selenium and from these states to singly excited states with the excited electron occupying the M shell have been calculated by relativistic distorted-wave Born procedures. The GRASP{sup 2} code was used for the atomic structure calculations. The continuum orbitals for the construction of continuum states were computed in the distorted-wave approximation, in which the distorted-wave potential used was the spherically averaged potential of the nucleus plus the potential of the bound electrons of the bound state. The cross sections for excitations were computed first by a 233-level multiconfiguration Dirac-Fock (MCDF) configuration expansion and then by a 279-level MCDF configuration expansion. The latter procedure, which also took into account contributions ...

International Nuclear Information System (INIS)

The mobility of oxidized astatine in solutions H(Na)ClO_4 (#mu#=0.4M)-1.10"-"4M K_2Cr_2O_7 has been measured at 25 degC in the interval 0.63<=pH<=1.68. Under these conditions astatine migrates to the cathode only. The speeds of the migration depends upon the concentration of hydrogen ions in solutions are: pH 1.68 Usub(c)=1.17.10"-"4 cm"2 V"-"1 s"-"1; pH 0.63 Usub(c)=2.67.10"-"4 cm"2 V"-"1 s"-"1. The effect agrees with the opinion that the singly charged cation of astatine formed in acidic solutions is a strong aquacomplex [(H_2O)sub(x)At]"+ (x=1-2) (protonated hypoastatic acid). Deprotonation constant of this cation is Ksub(dp)=0.032+-0.005. Specific properties of the astatine cation are given. They can be explained, probably, through the peculiarities of its structure. (author).

Science.gov (United States)

A technique is presented for the analyss of DNA histograms which is an extension of earlier discrete Gaussian summing methods. It alleviates the problems encountered with previous methods by extending the S-phase portions of the distribution under the G/sub 1/ and G/sub 2/ + M peaks. The resuts obtained by this method for the fraction of cells in the G/sub 1/, S, and G/sub 2/ + M phases of the life cycle are compared with autoradiographic results. With one or two exceptions which are discussed, agreement between autoradiography and the analytical method is good.

CERN Document Server

The recent measurements by the BES Collaboration of J/psi decays into a photon and a proton-antiproton pair indicate a strong enhancement at the proton-antiproton threshold not observed in the decays into a neutral pion and a proton-antiproton pair. Is this enhancement due to a proton-antiproton quasi-bound state or a baryonium? A natural explanation follows from a traditional model of proton-antiproton interactions based on G-parity transformation. The observed proton-antiproton structure is due to a strong attraction in the 1S0 state, and possibly to a near-threshold quasi-bound state in the 11S0 wave.

Energy Technology Data Exchange (ETDEWEB)

The Chediak-Higashi syndrome (CHS) is a severe autosomal recessive condition, features of which are partial oculocutaneous albinism, increased susceptibility to infections, deficient natural killer cell activity, and the presence of large intracytoplasmic granulations in various cell types. Similar genetic disorders have been described in other species, including the beige mouse. On the basis of the hypothesis that the murine chromosome 13 region containing the beige locus was homologous to human chromosome 1, we have mapped the CHS locus to a 5-cM interval in chromosome segment 1q42.1-q42.2. The highest LOD score was obtained with the marker D1S235 (Z{sub max} = 5.38; {theta} = 0). Haplotype analysis enabled us to establish D1S2680 and D1S163, respectively, as the telomeric and the centromeric flanking markers. Multipoint linkage analysis confirms the ...

Energy Technology Data Exchange (ETDEWEB)

Er{sub 3}NbO{sub 7} phosphor was synthesized by sintering a mixture of Er{sub 2}O{sub 3} and Nb{sub 2}O{sub 5} powder in a molar ratio of 3:1 at 1600 deg. C over 55 h. Optical absorption and emission characteristics of Er{sup 3+} ions in the calcined Er{sub 3}NbO{sub 7} powder were investigated and discussed compared with ErNbO{sub 4} phosphor and a Z-cut congruent Er (2 mol%):LiNbO{sub 3} single crystal. The absorption and emission studies show that, due to different crystal structures, the spectroscopic properties of these niobates have some differences in spectral shape, peak position, and relative intensity, especially at 1.5 {mu}m. The most obvious spectral feature of the Er{sub 3}NbO{sub 7} is that the spectral structure of band instead of peak is observed in its absorption or emission spectrum due to the existence of local structural disorder and multiple Er{sup 3+} sites. The Er{sub 3}NbO{sub 4} shows stronger upconversion emission than the single crystal but weaker than the ...

British Library Electronic Table of Contents (United Kingdom)

Background:- Only one study has used a prospective method to analyze the diagnostic stability of first psychotic episodes in children and adolescents. The Child and Adolescent First-Episode Psychosis Study (CAFEPS) is a 2-year, prospective longitudinal study of early-onset first episodes of psychosis (EO-FEP). Aim:- To describe diagnostic stability and the variables related to diagnostic changes. Methods:- Participants were 83 patients (aged 9-17-years) with an EO-FEP consecutively attended. They were assessed with a structured interview (Kiddie-Schedule for Affective Disorders and Schizophrenia, Present and Lifetime version) and clinical scales at baseline and after 2-years. Results:- The global consistency for all diagnoses was 63.9%. The small group of bipolar disorder had high stabilit...

International Nuclear Information System (INIS)

Full text: The nuclear renaissance, anticipated by AREVA in the beginning of the century is now happening in several countries around the world. The fundamentals being the increasing demand of energy, the volatility of fossil fuel prices, the awareness of climate change threat connected with the extensive use of fossil fuels. The EPRTM reactor present significant improvements compared to previous generation reactors enabling to reach an outstanding safety level (redundancy of safety systems, airplane crash resistance), to improve the economics (extended plant lifetime, flexibility and availability during operation and, increased efficiency and fuel utilization) while limiting the impact on workers and the environment. Several countries have been implementing the transition to third generation reactors. The presentation will analyze different examples in order to draw the lessons learned from this first wave and to set-up the criteria for a successful transition ...

International Nuclear Information System (INIS)

Measurements have been made of certain parameters relevant to the operation of electron-counting detectors. An experimental chamber consisting of a uniform-field drift tube and a coaxial proportional counter thas been employed to obtain data, at very low drift fields (E/p<0.02 V/cm Torr), on electron mobility and lifetimes in a range of gas mixtures. These mixtures included argon, methane, nitrogen and carbon dioxide. Measurements of single-electron spectra showed that, unexpectedly for the standard gas mixtures employed, useful departure from an exponential spectrum was not possible without the production of cathode secondaries. Although the present studies employed only the counter electrical signal the information obtained should be directly relevant to the operation of practical light-pulse systems. Examples of electron-counting spectra for soft X-rays are shown. (orig.).

International Nuclear Information System (INIS)

In this paper, steady-state isotopic transient kinetic analysis (SSITKA) is used to study two model reactions, CO oxidation and CO-NO reactions, on a typical formulation of a three-way auto-catalyst. Under steady-state conditions, abrupt switches in the isotopic composition of CO ("1"2C"1"6O/"1"3C"1"8O) were carried out to produce isotopic transients in both labeled reactants and products. Along with the determination of the average surface lifetimes and concentrations of reaction intermediates, an analysis of the transient responses along the carbon reaction pathway indicated that the distribution of active sites for the formation of CO_2 was bimodal for both reactions. Furthermore, relatively few surface sites contributed to the overall reaction rate.

Energy Technology Data Exchange (ETDEWEB)

Singlet-singlet and triplet-triplet absorption spectra of a series of methyl-alloxazines were calculated using the time-dependent density-functional theory approach and compared to experimental results. The B3LYP functional provides good correlation between experimental and theoretical results, given that solvent effects are disregarded in the present calculations. Substituent and solvent dependences of the lowest, closely spaced, n,{pi}* and {pi},{pi}* excited state energies are discussed, their order being of consequence in determining the non-radiative decay rates and thus emission quantum yields and lifetimes. The high quantum yields of singlet oxygen formation indicate that the triplet state is formed by efficient intersystem crossing from the first singlet excited state.

British Library Electronic Table of Contents (United Kingdom)

Severe affective and behavioral dysregulation, labeled as severe mood dysregulation (SMD), is a widely spread phenomenon among adolescent psychiatric patients. This phenotype constitutes severe impairment across multiple settings, including various symptoms, such as non-episodic anger, mood instability, and hyperarousal. Moreover, SMD patients often show depression and reduced need for sleep. Despite a lifetime prevalence of 3.3%, systematic research is still scarce, and treatments that have been established do not account for the range of symptoms present in SMD. Considering the circadian dysfunctions, two hormones, melatonin and cortisol, are essential. When these hormones are dysregulated, the circadian rhythm gets out of synchrony. Since evidence is emerging showing that the worse the ...

Energy Technology Data Exchange (ETDEWEB)

A total of 86 experimental fuel pins with various fuel, liner, and cladding candidate materials have been irradiated in the Experimental Breeder Reactor-II (EBR-II) and the Fast Flux Test Facility (FFTF) reactor as part of the SP-100 fuel pin irradiation testing program. Postirradiation examination results from these fuel pin are key in establishing performance correlations and demonstrating the lifetime and safety of the reactor fuel system. This paper provides a brief description of the in-reactor fuel pin tests and presents the most recent irradiation data on the performance of wrought rhenium (Re) liner material and high density UN fuel at goal burnup of 6 atom percent (at. %). It also provides an overview of the significant variety of other fuel/liner/cladding combinations which were irradiated as part of this program and which may be of interest to more advanced efforts.

International Nuclear Information System (INIS)

The strategy for the Korean nuclear power plant lifetime management (PLIM) program, which has been developed over the last 3 years, is introduced, together with descriptions of recent events and related maintenance activities. This leading Korean PLIM project has been focused on such areas as a plant data survey, screening and prioritization of systems, structures and components (SSCs), aging evaluation of major components, economic analysis and regulatory issues. The current status is outlined in terms of major tasks including aging evaluation of 13 major components. The future long-term plan which eventually aims at maximizing the economic benefit for both the utility and its customers is presented. Also described is the technical development required for plant life extension. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The calculated radioactive waste inventories of the Turkey Point pressurized water fission reactor (PWR) and the Starfire conceptual fusion tokamak are compared as a function of time from initial start-up to 10,000 years after decommissioning. Only material out of reactor at least one year is considered. The total activity in Ci/W(th) of the Starfire tokamak is slightly greater than that of the PWR during the active lifetimes of the two reactors and beyond 1000 years. However, using reduced activation materials in Starfire can result in about 1/2000 as much long-lived radioactivity as in the fission reactor. It is stressed that comparison of wastes on this basis is not straightforward, since the radioisotopes and methods required for their disposal are different for fusion and fission reactors. 2 refs., 1 fig., 2 tabs.

CERN Document Server

Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar companions, however, can significantly change this evolution through their tidal interactions. Stellar evolution and planet formation in binaries have to respond to an environment of truncated, quickly disappearing disks--very different compared to an isolated star environment. In order to investigate details of the influence of binarity on circumstellar disk evolution, we obtained adaptive optics supported near-infrared imaging and spectroscopy of the individual components of 22 low-mass binaries in the well-known Orion Nebula Cluster. Brackett gamma emission, which we detect in several systems, is used as a tracer for the presence of an active accretion disk around each binary component. We find a low fraction of accreting binary ...

International Nuclear Information System (INIS)

Silica glasses containing Pr"3"+ with and without CdS nanoparticles were prepared by sol-gel technique. The influence of CdS nanoparticles on Pr"3"+ doped glass was studied by absorption, photoluminescence and up-conversion. From the measured intensities of various absorption bands of these glasses, the Judd-Ofelt parameters ?_2, ?_4 and ?_6 have been evaluated. The radiative transition probability (A), radiative lifetime (?_R), branching ratio (?_R) and integrated emission cross-section (?_P) were calculated from excited states of "3P_1 and "3P_0 levels. The up-conversion emissions were found in the green, orange and red regions under 800 nm excitation with peaks 559, 612 and 688 nm respectively. On excitation with 370 nm also leads to similar green, orange and red regions.

Energy Technology Data Exchange (ETDEWEB)

This report describes progress during the first year of a three-year project. The objective of the research is to examine new design approaches for achieving very high conversion efficiencies. The program is divided into two areas. The first centers on exploring new thin-film approaches specifically designed for III-V semiconductors. The second area centers on exploring design approaches for achieving high conversion efficiencies without requiring extremely high quality material. Research activities consisted of an experimental study of minority carrier recombination in n-type, metal-organic chemical vapor deposition (MOCVD)-deposited GaAs, an assessment of the minority carrier lifetimes in n-GaAs grown by molecular beam epitaxy, and developing a high-efficiency cell fabrication process.

Energy Technology Data Exchange (ETDEWEB)

Excitation of low temperature helium or helium/water plasma and subsequent exposure to air of polyacrylonitrile (PAN) ultrafiltration membranes was used to hydrophilize the surface of these materials. We analyzed the effectiveness of this approach as a function of plasma operating variables including gas phase composition, plasma power, treatment time and system pressure. Following the changes in physical and chemical composition of the PAN surface resulting from these modifications was a major aspect of this work. Techniques such as the captive bubble contact angle method, ellipsometry, ESCA, and FTIR-ATR were all used. In addition, the formation and life-time of peroxides during these processes were determined. At low powers (<25W) and short treatment periods ({<=}30 sec), the main chemical conversion of PAN surfaces was simultaneous hydrophilization and stabilization via PAN cyclization. Relatively small water permeability changes were observed as a result ...

Energy Technology Data Exchange (ETDEWEB)

The findings reported in this study highlight several important features of the development of hematopoietic stem cells after transplantation into irradiated recipients. First, they demonstrate the existence of a class of primitive multipotential stem cells that can function for a significant portion of the lifetime of a mouse (15 mo). In addition, they clearly show that these primitive stem cells can be infected with recombinant retroviruses and thus would be appropriate targets for gene therapy in somatic tissues. Second, our data indicate that the progeny of some, but not all, of the primitive stem cells have fully expanded into the various hematopoietic lineages by 2 mo after reconstitution. Finally, our analysis of the secondary recipients provides strong evidence suggesting that the primitive stem cell population can actually clonally expand. Our current experiments are aimed at determining the extent to which this expansion can occur and whether or not this ...

Energy Technology Data Exchange (ETDEWEB)

Contamination and blockages of the cooling tubes in the turbine condenser disturb the heat transfer, thereby causing power losses at the turbine and increasing the fuel demand. Corrosions cause tubing leakages which require operating downtimes and reduce the lifetime of the pipes. Tube cleaning systems and backflushing cooling water filters eliminate these problems. Nevertheless it can come to coatings in the condenser tubes, if the tube cleaning equipment does not operate optimally or if coarse dirt is entered. Under this aspect, the author of the contribution under consideration reports on these problems on the basis of practical examples. The author gives references to the optimized operation of the tube cleaning system and the cooling water filtration.

International Nuclear Information System (INIS)

Possible mechanisms of the cumulative production of particles in the processes of high momentum transfers to complex systems are discussed. Production of the multi-nucleon systems, the so-called fluctons, during collision of a high-energy particle with a nucleus, is proposed as a most realistic explanation of the cumulative effect. A probability of the flucton production in nucleus and its interaction with the incident particle are investigated. A possible origin of fluctons, considered, in the framework of the quark bag model, as quasistable states with the definite coupling energy and the lifetime, is studied. A probability for the presence of a flucton, as multibaryon configuration in a nucleus is evaluated. The production of multibaryon configurations in a nucleus is demonstrated to show up as a presence of strong multiparticle repulsion at small distances, which cannot be reduced only to two-particle interactions.

British Library Electronic Table of Contents (United Kingdom)

Abstract Background The increase in the incidence of atopic dermatitis (AD) in developed countries has been related to familiar and environmental factors. This survey was undertaken to investigate the family background, birthweight and the home environment of children suffering from AD in order to point out the possible factors that provoke the development of the disease. Methods The study uses data collected by means of self-administered questionnaires and discusses 461 cases of children (age 0-12) with active skin signs of AD. The control group comprised of 343 children (age 0-12) with no skin signs or positive lifetime history of AD. Associations between familiar and various home environmental factors and the risk of AD were calculated by means of odds ratios. Results There were statist...

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND.The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) covers the direct clinical costs of breast and cervical cancer screening and diagnostic follow-up for medically underserved, low-income women. Personal costs are not covered. In this report, the authors estimated personal costs per woman participating in NBCCEDP mammography screening by race/ethnicity and also estimated lifetime personal costs (ages 50-74 years).METHODS.A decision analysis model was constructed and parameterized by using empiric data from a retrospective cohort survey of mammography rescreening among women ages 50 years to 64 years who participated in the NBCCEDP. Data from 1870 women were collected from 1999 to 2000. The model simulated the flow of resources incurred by a woman participat...

International Nuclear Information System (INIS)

From self-consistent band structure calculations using the 'augmented plane wave'(APW) method, the density of states can be decomposed into local partial (according to azimuthal quantum number l) components, the l-character densities. Within the APW formalism the intensity of X-ray emission spectra is determined by radial transition probabilities and l-character densities of such valence states, which reside inside the same atomic sphere as the core vacancy and whose quantum number l differs by +-1 from the one corresponding to the core state. By taking into account lifetime broadening of the core and valence states and also the instrumental broadening the computed spectra (non-metal K-, vanadium K- and Lsub(III)-spectra) agree well with experiment. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Recently, we have found the anomalous degradation of electrical performance in silicon solar cells irradiated with charged particles in a high-fluence region. This anomalous phenomenon has two typical features, which are sudden-drop-down of electrical performances in a high-fluence region and slight recovery of the short circuit current I{sub SC} just before the sudden-drop-down. These features cannot be understood by a conventional model coming from the decrease of minority-carriers life-time. We introduce this anomalous degradation of the electrical performance in Si solar cells irradiated with electrons or protons. We also report the result of simulation for the fluence dependence of the I{sub SC}, and discuss the mechanism of this anomalous phenomenon. (author)

CERN Document Server

Mono-layers of stearic and behenic acids and mixtures of them in different proportions, deposited with the Langmuir-Blodgett technique, were used to study the alignment and the alignment dynamics in nematic liquid crystal cells. A relaxation process from a splay-bend flow induced metastable orientation to the homeotropic one occurs. The lifetime of the metastable state was found to depend on the mono-layer composition. The transition between the homeotropic and the conical anchoring was found to be irreversible in the case of the mixed aligning mono-layers: on cooling from the isotropic phase a quasi-planar nematic state (schlieren texture) appears. It is stable in a range of a few degrees below the clearing point and, on decreasing the temperature, relaxes to the homeotropic state in form of expanding domains.

CERN Document Server

This work presents accurate ab initio determination of the hyperfine splitting for the ground state and few low-lying excited states of 113Cd+; important candidates for the frequency standard in the microwave region, using coupled-cluster theory (CC) in the relativistic framework. The calculated hyperfine splitting are well in agreement with recent experimental results. We have also carried out the lifetimes of the 5p2P1=2 and 5p2P3=2 states, which are in well agreement with recent experimental result (Moehring et al., PRA 73 023413, 2006). The roles of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented in the CC terms.

CERN Document Server

In the CERN approach to the design of a neutrino factory, the repetition frequency of the proton beam is high enough to consider stationary solid targets as a viable solution for multi-MW beams. The target consists of high density tantalum spheres of 2 mm diameter which can efficiently be cooled by passing a high mass flow He-gas stream through the voids between the Ta-granules. Very small thermal shocks and stresses will arise in this fine grained structure due to the relatively long burst of 3.3 ms from the SPL-proton linac. In a quadruple target system where each target receives only one quarter of the total beam power of 4 MW, conservative temperature levels and adequate lifetimes of the target are estimated in its very high radiation environment. A conceptual design of the integration of the target into the magnetic horn-pion-collector is presented.

International Nuclear Information System (INIS)

Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF_4) and acetylene (C_2H_2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF_4/(CF_4+C_2H_2). The samples were annealed at 300 deg. C for 30 min. in a N_2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF_4 flow ratio (R=0.97) produced more sp"3 linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 #mu#s and an energy gap of #approx#2.75 eV were observed in both the as-deposited and after annealing conditions. The short carriers ...

International Nuclear Information System (INIS)

This thesis presents a theoretical analysis of the properties of the Higgs bosons in the standard model (SM) and the minimal supersymmetric extension (MSSM), which can be investigated at the LHC and e"+e"- linear colliders. The final goal is the reconstruction of the Higgs potential and thus the verification of the Higgs mechanism. MSSM Higgs boson production processes at future #gamma##gamma# colliders are calculated in several decay channels. Heavy scalar and pseudoscalar Higgs bosons can be discovered in the bb final state in the investigated mass range 200 to 800 GeV for moderate and large values of tan#beta#. The #tau#"+#tau#"- channel provides a heavy Higgs boson discovery potential for large values of tan#beta#. Several mechanisms that can be exploited at e"+e"- linear colliders for the measurement of the lifetime of a SM Higgs boson in the intermediate mass range are analysed. In the WW mode, the lifetime of Higgs scalars with masses ...

Energy Technology Data Exchange (ETDEWEB)

This report for the Swiss Federal Office of Energy (SFOE) presents the overview reports made by SFOE Heads of Program on work done in 2007. Projects reported on in the natural gas-fired fuel cell area include the EU-project REAL-SFOC, the long-term testing of anode-supported SOFC stacks, intermediate-temperature fuel cells based on proton conducting electrolytes, the interdisciplinary ONEBAT project and lifetime-enhancement of SOFC stacks for CHP applications. In the polymer-electrolyte fuel cell (PEFC) area, projects concerning proton-conducting polymer membranes, factors limiting the lifetime of fuel cell membranes, a new highly active oxygen reduction electrode for PEM fuel cell and zinc/air battery applications, the enhancement of PEFC durability and reliability, model-based investigation of PEFC performance, and local gas analysis of PE fuel cells are briefly reported on. Long-term research activities in the hydrogen technology area ...

Energy Technology Data Exchange (ETDEWEB)

Topics concerning the problems associated with older and aging dams are considered including: what can be done to extent the lifetime of an old dam, the decision to decommission a dam based on a value judgment that the risk of maintaining the dam is too great for society's acceptance, the possibility of change in the level of risk tolerance with time in a technological environment, traditional surveillance methods used by dam owners in the Y2K situation, and the unreality of dam immortality. Trends and means for preserving older dams for their owner's purposes are outlined, as well as their lifetime compared to that of the downstream systems they serve. Despite the fact that we live in a throwaway society, dam owners cannot just leave their dam asset when they are through with using it. Someone has to maintain the dam, or ensure that it is safely decommissioned when the owner is finished with it. On a worldwide scale the ...

Energy Technology Data Exchange (ETDEWEB)

Experiments for lifetime prediction of the first wall are being carried out within the framework of the European fusion reactor programme. Defects such as notches and cavities may develop in the first wall and may initiate under cyclic thermal stress cracking processes which may reduce the service life of the material. For examination of crack growth, specimens with defined initial notches were prepared and subjected to cyclic thermal loads. The paper shows that the eddy current method is suitable for detecting and revealing the crack growth processes even under conditions of complex geometry, as e.g. cracks in inner bores. The experiments indicated particularly susceptible, critical spots in the first wall and yielded crack growth rates of use for lifetime calculations. (orig./CB) [Deutsch] Im Rahmen des europaeischen Fusionsreaktorprogramms werden Untersuchungen zur Lebensdauervorhersage der Ersten-Wand durchgefuehrt. Die Erste-Wand kann ...

International Nuclear Information System (INIS)

The results of investigation into a new series of Z-even nuclei - precursors of delayed protons (PDP) -"6"5Ge, "8"9Se, "9"3Kr, "8"1Zr, and "8"5Mo are presented. PDP were obtained by irradiation of targets in the following reactions: Zn(He, 2n) "6"5Ge, 22 MeV; "4"0Ca("3"2S, 2 pn) "1"9Se, 100 MeV; "6"0Ni ("1"60, 3 n), "7"3Kr, 75 MeV; "5"2Cr ("3"2S, 3n)"8"1Zr, 110 MeV; "5"6Fe("3"2S, 3n)"8"5Mo, 120 MeV. The targets (self-sustaining foils of thickness approximately 1.2 mg/cm"2) were placed at an angle of 15 deg to the direction of the ion beam. Upon irradiation targets were moved downwards into a measuring position. The spectra of protons, X and gamma-rays, and also the spectra of p - x, p-#gamma#, x - #gamma# coincidences accompanying the decay of "6"5Ge, "6"9Se,"7"3Kr and "8"1Zr, and "8"5Mo were measured. The measured half-lives are equal, to 31.5+-1.9, 27.3+-0.5, 28.5+-1.1, 6.3+-0.5, and 5.6 +-0.9 s respectively. The experimental spectra are compared with the calculated ones. The proton ...

Energy Technology Data Exchange (ETDEWEB)

We report on the single and double multiphoton ionization of ground state Sr atoms observed in an atomic beam experiment with laser pulses of {approx}5 ns duration, maximum intensity {approx}4 x 10{sup 11} W cm{sup -2} and within the 710-740 nm wavelength range. The Sr{sup +} spectrum consists of two strong lines originating from three-photon resonant four-photon ionization of bound states, a number of weak autoionizing resonances and a broad line due to four-photon excitation of the doubly excited 5p{sup 2} {sup 1}S{sub 0} state. The latter, along with a strong, broad and structured spectral feature, is also evident in the wavelength dependence of the doubly charged Sr{sup 2+} ion. A weakly evident but reproducible inflection point ('knee' structure) appears in the intensity dependence of the Sr{sup 2+} yield at the location of the 5p{sup 2} {sup 1}S{sub 0} resonance. A complementary ...

International Nuclear Information System (INIS)

A scheme of evaluating a generalized three-photon excitation cross section #sigma#/sub (3)/ in neutral atomic argon at 3144.67 A is outlined. Three photons at this wavelength can excite the neutral argon atoms from the ground 3p"6 "1S_0 state to the 3p"54s'[1/2]_1"0 state. The fourth photon will ionize the argon atoms. Assuming linear polarization of the incident laser radiation, contributions from several channels in various energy-level schemes are summed in the evaluation of the transition probability. For a laser linewidth of #DELTA##lambda#/sub L/ = 1 A, our maximum numerical value of the computed result for the three-photon excitation cross section is #sigma#/sub (3)/ = 1.414 x 10/sup -80/ cm"6 s"2. .AE.

British Library Electronic Table of Contents (United Kingdom)

The oxidation of n-butylbenzene was studied in a jet-stirred reactor (JSR) at 10atm in dilute conditions providing new experimental results over the low- and high-temperature range 550-1180K, and variable equivalence ratio (0.25ϕ1.5). They consisted of concentration profiles of the reactants, stable intermediates and final products, measured as a function of temperature, at a constant residence time of 1s, by sonic probe sampling followed by on-line GC-MS and off-line GC-TCD-FID and GC-MS analyses. The oxidation of n-butylbenzene in these conditions was modeled using a detailed chemical kinetic reaction mechanism (404 species and 2210 reactions, most of them reversible) deriving from a previous scheme proposed for the ignition, oxidation, and combustion of simple aromatics (benzene,...

Energy Technology Data Exchange (ETDEWEB)

To measure electron reactions on a picosecond timescale the investigators developed a picosecond pulse-conductivity technique, which makes use of the electron fine-structure pulses of our LINAC (pulse width 25 vs FWHM) to produce excess electrons and now detects changes in sample conductance under optimum conditions with an instrumental response of 18 ps. This resolution is in agreement with a theoretical estimate. This technique has been successfully applied to study excess electron reactions in solvents covering a mobility range from 0.24 to 100 cm/sup 2/V/sup -1/s/sup -1/; extension to lower mobility liquids seem possible.

British Library Electronic Table of Contents (United Kingdom)

We have developed a process for chemical purification of carbon nanotubes for solution-processable thin-film transistors (TFTs) having high mobility. Films of the purified carbon nanotubes fabricated by simple drop coating showed carrier mobilities as high as 164 cm2V?1s?1, normalized transconductances of 0.78 Sm?1, and on/off current ratios of 106. Such high performance requires the preparation of a suspension of micrometer-long and highly purified semiconducting single-walled carbon nanotubes (SWCNTs). Our purification process includes length and electronic-type selective trapping of SWCNTs using recycling gel filtration with a mixture of surfactants. The results provide an important milestone toward printed high-speed and large-area electronics with roll-to-roll and ink-jet device fabri...

International Nuclear Information System (INIS)

We consider particle evaporation and fission of an ensemble of hot, rotating compound nuclei as a stochastic process. We derive a set of coupled differential equations formed by a Fokker-Planck equation describing fission, and master equations for calculating particle evaporation. From these equations, we are able to determine multiplicities of prefission neutrons, protons and #alpha#-particles, their energy spectra and their angular momentum distributions. A comparison of our results with experimental data provides us with information regarding the reduced friction coefficient #beta#, the fission barrier height and the level density parameter. For different iridium isotopes, ("1"8"1","1"8"5","1"8"7Ir), "1"8"5Os and "1"5"8Er, we obtain as an upper limit #beta##<=#8.0x10"2"1 s"-"1. (orig.).

Science.gov (United States)

The performance of 250 different computational protocols (combinations of density functionals, basis sets and methods) was assessed on a set of 165 well-established experimental (1)H-(1)H nuclear coupling constants (J(H-H)) from 65 molecules spanning a wide range of "chemical space". Thereby we found that, if one uses core-augmented basis sets and allows for linear scaling of the raw results, calculations of only the Fermi contact term yield more accurate predictions than calculations where all four terms that contribute to J(H-H) are evaluated. It turns out that B3LYP/6-31G(d,p)u+1s is the best (and, in addition, one of the most economical) of all tested methods, yielding predictions of J(H-H) with a root-mean-square deviation from experiment of less than 0.5 Hz for our test set. Another method that does similarly well, without the need for additional 1s basis functions, is B3LYP/cc-pVTZ, which is, ...

Science.gov (United States)

In vertebrates, the positioning of the internal organs relative to the midline is asymmetric and evolutionarily conserved. A number of molecules have been shown to play critical roles in left-right patterning. Using representational difference analysis to identify genes that are differentially expressed on the left and right sides of the chick embryo, we cloned chick Claudin-1, an integral component of epithelial tight junctions. Here, we demonstrate that retroviral overexpression of Claudin-1, but not Claudin-3, on the right side of the chick embryo between HH stages 4 and 7 randomizes the direction of heart looping. This effect was not observed when Claudin-1 was overexpressed on the left side of the embryo. A small, but reproducible, induction of Nodal expression in the perinodal region on the right side of the embryo was noted in embryos that were injected with Claudin-1 retroviral particles on their right sides. However, no changes in Lefty,Pitx2 or cSnR expression were observed. ...

Energy Technology Data Exchange (ETDEWEB)

The unknown {beta}-decay half-lives of 22 isotopes far off stability (5 < T{sub Z} < 10) in the region from Ti to Ni were measured at GSI, Darmstadt. The nuclei were produced in a fragmentation reaction of 500 A.MeV {sup 86}Kr-projectile impinging on a thick Be target. The isotopes of interest were separated and identified with the fragment separator, FRS, by a combination of B{rho},Z, and ToF techniques. An additional range separation was performed by a selective implantation into granular detectors. The spatial and time correlations of the implant with the consecutively detected {beta}-particles were used to determine the unknown half-lives. For nuclei far off stability, {beta}-decay chains were measured and analyzed as well, leading to an even more reliable evaluation of the lifetimes. The large discrepancies found between the measured and the theoretical values emphasize that most recent theoretical work is not an improvement over calculations made almost ...

Energy Technology Data Exchange (ETDEWEB)

Vanadium alloys exhibit important advantages as a candidate structural material for fusion first wall/blanket applications. These advantages include fabricability, favorable safety and environmental features, high temperature and high wall load capability, and long lifetime under irradiation. Vanadium alloys with (3-5)% chromium and (3-5)% titanium appear to offer the best combination of properties for first wall/blanket applications. A V-4Cr-4Ti alloy is recommended as the reference composition for the ITER application. This report provides a summary of the R&D conducted during 1994 in support of the ITER Engineering Design Activity. Progress is reported for Vanadium Alloy Production, Welding, Physical Properties, Baseline Mechanical Properties, Corrosion/Compatibility, Neutron Irradiation Effects, Helium Transmutation Effects on Irradiated Alloys, and the Status of Irradiation Experiments. Separate abstracts have been prepared for individual reports from this ...

CERN Document Server

A stellar evolution computer model has been used to determine changes in the luminosity L and effective temperature T(e) of single stars during their time on the main sequence. The range of stellar masses investigated was from 0.5 to 1.5 times that of the Sun, each with a mass fraction of metals (metallicity, Z) from 0.008 to 0.05. The extent of each star's habitable zone (HZ) has been determined from its values of L and T(e). These stars form a reference framework for other main sequence stars. All of the 104 main sequence stars known to have one or more giant planets have been matched to their nearest stellar counterpart in the framework, in terms of mass and metallicity, hence closely approximating their HZ limits. The limits of HZ, for each of these stars, have been compared to its giant planet(s)'s range of strong gravitational influence. This allows a quick assessment as to whether Earth-mass planets could exist in stable orbits within the HZ of such systems, both presently and ...

International Nuclear Information System (INIS)

There is no possibility to check any inner part at real welded joint at nuclear power station (NPS) during operation because any destructive test cannot be used. In practice there is checked surface of weld. There are used four methodical instructions for the check of real welds: 1. The visual inspection, 2. The measurement of hardness, 3. The chemical composition checking and 4. The microstructure replica analysis. It is necessary to know how these information of weld surface are in accordance with characteristics of inner parts of weld. If there is not any difference between surface weld microstructure and internal weld microstructure of experimental weld it is supposed to that there is not any difference in other measured properties of welds. If is changed structural characteristics of microstructure, it is changed also hardness, chemical analysis etc. It was observed that the microstructure of real welds is almost the same with simulated weld and also the surface microstructure of ...

Energy Technology Data Exchange (ETDEWEB)

The thermal radiation which generated from the patterned Ta/Pt/Ta thin heater achieved a high temperature up to 1010 {sup o}C under applied current of 2.4 A. In order to reduce an electromigration at high current of 2 A, a Ta capping layer was placed on the Pt layer instead of conventional capping layer, such as SiNx and CoWP. Under the thermal radiation at the applied current of 2 A in the Ta/Pt/Ta thin heater, the Ta capping layer enhanced the lifetime of the Pt thin heater up to 5 h. A stamping process for the crystallization of a-Si was performed for 40 samples using the Ta/Pt/Ta thin heater. For all samples, a-Si has been selectively crystallized and Raman peaks were located near 519 cm{sup -} {sup 1}. These results indicated that the thermal radiation of the Ta/Pt/Ta thin heater was maintained constantly due to the Ta capping.

International Nuclear Information System (INIS)

The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, 1H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-? interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the ...

International Nuclear Information System (INIS)

Mixed carbide fueled driver assembly experiments will be tested in FFTF fuel driver positions as part of the National Advanced Fuel Program. The design of the experiment flow ducts must assure conformance to FFTF functional requirements in addition to service as a test vehicle for the carbide fuel irradiations. Test goals of damage fluence burnup, and fluence to burnup ratio exceed those of the standard oxide fueled drivers. As a consequence, the 20% cold worked type 316 stainless steel material of construction will experience significant irradiation induced creep and swelling. Additionally, the flow duct design must withstand the enhanced thermal transients produced by the action of carbide fuel during reactor scrams. A major FFTF functional requirement is that adjacent flow ducts do not touch each other except at the load pads. This requires a realistic analysis of the creep and swelling deformation of the flow duct during an experiment lifetime. Flow duct ...

Energy Technology Data Exchange (ETDEWEB)

Visual excitation is initiated by the absorption of a photon by the 11-cis retinal chromophore bound within the pigment called rhodopsin. We have used a variety of vibrational spectroscopies to obtain information about the vibrational nuclear dynamics that lead to this efficient photochemical isomerization. The cis-trans isomerization in rhodopsin is complete in only 200 fs. The extreme speed of this process, which is consistent with the {approximately}50 fs lifetime indicated by the spontaneous emission yield, suggests that the photochemistry involves non-stationary states or vibrational coherence. Recent studies have in fact observed vibrationally coherent oscillations of the ground state photoproduct called bathorhodopsin following impulsive excitation of the rhodopsin reactant. This conclusively demonstrates that the isomerization process in rhodopsin is vibrationally coherent. These observations further suggest that the isomerization quantum yield is directly ...

International Nuclear Information System (INIS)

A trans-uranium (TRU) fuel should be manufactured and loaded in transmutation systems in order to transmute the long-lived TRU nuclides into short-lived ones. However, since all of the TRU nuclides are not completely transmuted in one cycle lifetime in transmutation systems, the spent TRU fuel has to be treated to recover the long-lived radionuclides or fuel matrix materials. One concept to manufacture TRU fuel for transmutation is to recover uranium from TRU and molten salt. If this type of fuel is adopted for transmutation, uranium could also be an objective material to be recovered and recycled. Since electrowinning is a promising technology to be employed for the recovery of uranium from fuel materials, some experimental work of electrowinning using anode of Cd-Li alloy was carried out in this study. The basic salt chosen was a mixture of LiCl-KCl which has an eutectic point at 357 .deg. C

Energy Technology Data Exchange (ETDEWEB)

Quantitative estimates of lung cancer risk from exposure to diesel engine emissions were developed using data from three chronic bioassays with Fischer 344 rats. Human target organ dose was estimated with the aid of a comprehensive dosimetry model. This model accounted for rat-human differences in deposition efficiency, normal particle clearance rates, transport of particles to lung-associated lymph nodes, respiration rates, and lung surface area, as well as high-dose inhibition of particle clearance. Recent evidence indicates that the inert carbon core of the diesel particulate matter is likely to be the primary source of carcinogenicity. The epithelial tissue lining the alveoli and lower airways is the primary target site for induction of lung tumors. Dose was therefore based upon the concentration of carbon particulate matter per unit lung surface area. Unit risk estimates were developed using either a time-to-tumor or a linearized multistage model. The unit risk estimates, defined ...

International Nuclear Information System (INIS)

Methodology based on probabilistic fracture mechanics (PFM) is finding increasing acceptability in demonstrating safety of Nuclear Power Plant (NPP) piping. In PFM, the methods of fracture mechanics and reliability theory are combined for assessing the reliability of components, which contain cracks. In this work, reliability assessment of Tarapur Atomic Power Plant (TAPP) 3-4 Primary Heat Transport (PHT) piping is done using PFM. Monte Carlo simulation with stratified sampling is used as a variance reduction technique. PFM model assumes a pre-existing circumferential surface crack before the start of plant operation. The crack grows in size during the lifetime of the plant due to the fatigue loading. This part-through wall crack having escaped hydro-test and pre-service inspection, may result in either a through wall flaw (leak) or may lead to the rupture of the piping. R6 method is used as failure criteria. Steam generator inlet (SGI), steam generator outlet ...

Energy Technology Data Exchange (ETDEWEB)

Heat exchangers for high and ultrahigh temperatures are a need and a precondition to realise high efficient fossil fired power plants based on the so-called Externally Fired Combined Cycle (EFCC) or the Indirect Fired Gas Turbines (IFGT). The main target of both processes is to increase the thermal efficiency of existing power plants by approximately 25% resulting in the same decrease in fuel consumption and, therefore, in the same reduction of CO{sub 2} formation. The main activities of the MPA University of Stuttgart in this project is focused on the characterisation and qualification of the structural material of the ultrahigh temperature heat exchanger (UHTHE) necessary in the above mentioned processes. The influence of the temperature and load on the material behaviour have been analysed by means of tensile tests and creep tests. The effectiveness of different coating systems and the interaction between coating system and basic material was also investigated. Additionally a set of ...

International Nuclear Information System (INIS)

The proceedings include the following lectures: Facing the challenges - new structures for electricity production. Renewable energies in Europe - chances and challenges. Nuclear outlook in the UK. Sustainable energy for Europe. Requirements of the market and the grid operator at the electricity production companies. Perspectives for the future energy production. Pumped storage plants - status and perspectives. Nuclear power/renewable energies -partners or opponents? New fossil fired power stations in Europe - status and perspectives. Nuclear energy: outlook for new build and lifetime extension in Europe. Biomass in the future European energy market - experiences for dong energy. Meeting the EU 20:20 renewable energy targets: the offshore challenges. DESERTEC: sustainable electricity for Europe, Middle East and North Africa. New power plants in Europe - a challenge for project and quality management. Consideration of safely in new build activities of power plants. ...

Energy Technology Data Exchange (ETDEWEB)

This project has received DOE support since July 1, 1978. During this period, 40 papers have been published dealing predominantly with chlorophyll-photosensitized electron transfer reactions in a variety of media (solutions, polymer films, lipid bilayer membranes). The overall theme of this work has been to develop mechanistic strategies f or photochemical energy storage via chlorophyll, using the green plant photosynthetic system as a paradigm for designing in vitro systems. Microheterogeneous lipid vesicle suspensions allow ready application of time-resolved optical spectroscopy to follow the course of light-induced electron transfer processes. Both the yields and the lifetimes of electron transfer products were markedly improved in the vesicle systems. In subsequent studies, this compartmentalization was favorably manipulated by controlling the electrical charge on the membrane surface, by controlling the solubility properties of the acceptors, by varying the ...

International Nuclear Information System (INIS)

We have developed a photon accumulated laser mass spectrometer that enables us to identify isomers of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran. This system is comprised of a high temperature (230 deg. C) pulsed gas injector (PGI), multimirror multipath system (MMS), and the conventional time-of-flight mass spectrometer. The PGI induces the formation of a choked supersonic jet gas pulse that cools down to a temperature to restrain fragmentation and reduces vibrational and rotational thermal noises. The results suggest that the excited lifetime numbers and fragment dynamics of these species change completely with jet cooling of molecules. The MMS enhances the soft ionization efficiency (by a factor of 1000 over a single path system) through photon accumulation by extending the irradiation duration (to about 40 ns) and volume, and it further minimizes fragmentation by carefully controlling the laser intensity distribution within the ionization ...

International Nuclear Information System (INIS)

A merged-beams electron-energy-loss technique is described, by which absolute cross sections can be measured for near-threshold electron-impact excitation of multipy charged ions. Results are reported here for absolute total electron-impact excitation cross sections for the O"5"+(2s#->#2p) transition from below threshold to 1.6 eV above threshold. The experimental data are in good agremeent with a seven-state close-coupling calculation throughout the energy range of the experiment. Results agree with calculations showing that more than 90% of the electrons causing excitation are ejected in the backward direction in the center-of-mass frame. This backscattering is shown in both quantum-mechanical and semiclassical calculations. Evidence is observed for high-lying metastable autoionizing states with a lifetime of approximately 0.9 #mu#s which are made to ionize by electron impact.

International Nuclear Information System (INIS)

Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original 'Bohunice' design in period 1994-1998. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Moessbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Moessbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filter deposits. The corrosion of new feed water pipelines system (from austenitic steel) in combination to innovated operation regimes goes dominantly to magnetite. The hematite presence is mostly on the internal surface of steam generator body and its concentration increases towards the top of the body. In the results interpretation it is necessary to consider also erosion ...

Energy Technology Data Exchange (ETDEWEB)

This work concerns the study of the nuclear superdeformation phenomenon in the rare earth region (A {approx} 150). The superdeformed (SD) states in Gadolinium and Dysprosium isotopes were produced via heavy-ion induced reactions and studied with the (EUROGAM EUROpean GAmma-ray Microscope) gamma multidetector array. Precise level attenuation method (DSAM). From the derived quadrupole moments, we find large differences in deformation between the yrast bands in neighbour nuclei explained in terms of the case of nuclei corresponding to an axis ratio of 2:1, the shell gaps are not fixed at a specific particle number and deformation. Furthermore the present results indicate that the deformations associated with identical bands are different supporting the picture that mass and deformation changes tend to compensate in SB bands with the same moments of inertia. (author). 114 refs.

Environmental Research Database

ObjectivesThe main objective of this study is to address the following specific questions: 1. Are the delayed effects of poor early diet on whole organism performance and senescence contingent on, or exacerbated by, the subsequent occurrence of compensatory growth? 2. Does the rate of growth influence levels of resting metabolism and/or oxidative stress, and if so, for how long does this persist? 3. How are the levels of early nutrition, growth, resting metabolism and oxidative stress linked to the lev [continued...]DescriptionIt is now widely appreciated that, while animals may appear to recover from periods of poor food quality or quantity experienced in early development, adverse effects may occur later in adult life. Such effects can influence the performance of complete cohorts of animals, and have important consequences for population dynamics. The reasons why such delayed effects occur across the animals' lifetimes are poorly understood. Following a period ...

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Nature uses chlorophyll and other porphyrinic pigments to capture and transfer light energy as a preliminary step in photosynthesis. The design of synthetic assemblies of light harvesting and energy directing pigments has been explored through synthesis and characterization of porphyrin oligomers. In this project, pigment electronic and vibrational structures have been explored by electrochemistry and dynamic and static optical measurements. Transient absorption data reveal energy transfer between pigments with lifetimes on the order of 20--200 picoseconds, while Raman data reveal that the basic porphyrin core structure is unperturbed relative to the individual monomer units. These two findings, along with an extensive series of experiments on the oxidized oligomers, reveal that coupling between the pigments is ...

CERN Document Server

Cell membranes are studded with protrusions that were thoroughly analyzed with electron microscopy. However, the nanometer-scale three-dimensional motions generated by cell membranes to fit the topography of foreign surfaces and initiate adhesion remain poorly understood. Here, we describe the dynamics of surface deformations displayed by monocytic cells bumping against fibronectin-coated surfaces. We observed membrane undulations with typically 5 nm amplitude and 5-10 second lifetime. Cell membranes behaved as independent units of micrometer size. Cells detected the presence of foreign surfaces at 50 nm separation, resulting in time-dependent amplification of membrane undulations. Molecular contact then ensued with apparent cell-membrane separation of 30-40 nm, and this distance steadily decreased during the following tens of seconds. Contact maturation was associated with in-plane egress of bulky molecules and robust membrane fluctuations. Thus, membrane ...

International Nuclear Information System (INIS)

First structural wall material (FSW) materials in inertial fusion energy (IFE) power reactors will be irradiated under typical repetition rates of 1-10 Hz, for an operation time as long as the total reactor lifetime. The main objective of the present work is to determine whether a continuous-pulsed (CP) approach can be an efficient method in modeling the pulsed activation process for operating conditions of FSW materials. The accuracy and practicability of this method was investigated both analytically and (for reaction/decay chains of two and three nuclides) by computational simulation. It was found that CP modeling is an accurate and practical method for calculating the neutron-activation of FSW materials. Its use is recommended instead of the equivalent steady-state method or the exact pulsed modeling. Moreover, the applicability of this method to components of an IFE power plant subject to repetition rates lower than those of the FSW is still being studied. The ...

International Nuclear Information System (INIS)

In support of a project on lifetime calculation experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K"I"s"c"c, and the crack growth rate were made to predict evolution of damage in tube walls. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that the material of SG tubes is sensitive to transgranular environmentally assisted cracking in the three basic concentrated environments used, alkaline, neutral and acid. The most corrosive medium was the acid environment. The crack ...

International Nuclear Information System (INIS)

Economic analysis was performed at KAERI with the assistance of US DOE to compare single reactor fuel cycle costs for a once-through option and a thermal recycle option to operate 1 GWe of a PWR plant for its lifetime. A reference fuel cycle cost was first calculated for each option with best estimated reference input data. Then a sensitivity analysis was performed changing each single value of such fuel cycle component costs as yellow cake price, enrichment charges, spent fuel storage cost, reprocessing cost, spent fuel disposal cost and reprocessing waste disposal cost. Savings due to thermal recycle in requirements of uranium, conversion, and enrichment were examined using formulas suggested by US DOE, while MOX fabrication penalty was accounted for. As a result of the reference fuel cycle cost analysis, it is calculated that the thermal recycle option is marginally more economical than the once-through option. The major factors affecting the comparative costs ...

Energy Technology Data Exchange (ETDEWEB)

Progress in the development of high-efficiency GaAs solar cells on low-cost, large-area, large-grain, optical-grade polycrystalline Ge substrates is described in this paper. First, we present results on the growth of specular GaAs-AlGaAs layers, across the various crystalline orientations of a polycrystalline Ge substrate, by metallorganic chemical vapor deposition (MOCVD). Second, we present the preliminary optimization of minority-carrier properties of GaAs-AlGaAs structures on poly-Ge substrates towards the improvement of GaAs solar cells. We have demonstrated comparable minority-carrier lifetimes in GaAs double-hetero structures grown on optical-grade poly-Ge substrates and electronic-grade single-crystal Ge substrates. In addition, we describe device-structure optimization that have led us to achieve a open-circuit voltage of {approximately}1 Volt in a GaAs solar cell on poly-Ge and to improve our previous best efficiency from 15.8{percent} for a 1-cm{sup ...

Energy Technology Data Exchange (ETDEWEB)

The microelectronic cable diagnosis is a substantial tool to determine destruction free the residual strength and the lifetime of laid PE/XLPE medium voltage cables. Fundamentals of the ageing diagnosis and a cost reduced inspection concept are the `Isothermal-Relaxation-Current` Analysis and the Neuro-Fuzzy evaluation software. These new tools are able to determine the ageing status of the investigated cable without any references. The authors also show that the test breakdown during the assessment of the ageing status of criterial systems can be reduced by this approach. The cable diagnosis equipment KDA is also useful for the steering of investment as well as for preventive maintenance. (orig.) [Deutsch] Die zerstoerungsfreie dielektrische Kabeldiagnostik kann heute einen wesentlichen Beitrag zur Bestimmung der Restfestigkeit und der Restlebensdauer eines PE/VPE-isolierten Mittelspannungskabels leisten. Basis der Alterungsdiagnose und des Konzeptes zur ...

Energy Technology Data Exchange (ETDEWEB)

The CleverFarm project started out to build an integrated monitoring system for wind farms, where all information would be available and could be used across the wind farm for maintenance and component health assessments. This would enable wind farm operators to prioritise their efforts, since they have a good view of the farm status from home. A large emphasis was placed on the integration of condition monitoring approaches in the central system, enabling estimates of the remaining lifetime of components, especially in the nacelle. During the 3,5 years of the project, software and hardware was developed and installed in two wind farms in Denmark and Germany. The connected hardware included two different condition monitoring systems based on vibration sensors from Gram&Juhl and ISET, plus a camera system developed by Overspeed. Additionally, short-term predictions of the wind farm output were delivered by DMI and Risoes Prediktor system throughout the ...

International Nuclear Information System (INIS)

The CAMDU 6 reactor has an international reputation as one of the world's best performing and safe reactors. CANDU 6 reactors are consistently ranked in the world's top 10 for annual and lifetime performance. Six CANDU 6 units are currently in operation in four continents; in Quebec, New Brunswick, South Korea, Argentina and Romania. There are another two CANDU 6 units currently under construction at wolsong, in Korea which ore scheduled to go into service in 1998 and 1999 respectively. A second CANDU 6 unit is currently being considered for Romania. The construction of two CANDU 6 units at Qinshan, in China, is now underway. The performance of the four first-generation CANDU 6 plants, which have now been in service for 15 years, continue to show very good performance, with capacity factors on average since in-service of over 85%. The annual capacity factor of 10.21% during 1997 has been achieved by the Wolsong-1 unit in South Korea. These high capacity factors ...

CERN Document Server

Gamma-Ray Bursts (GRBs) are thought to originate at cosmological distances from the most powerful explosions in the Universe. If GRBs are not beamed then the distribution of their number as a function of gamma-ray flux implies that they occur once per (0.3-40) million years per bright galaxy and that they deposit >10^{53} ergs into their surrounding interstellar medium. The blast wave generated by a GRB explosion would be washed out by interstellar turbulence only after tens of millions of years when it finally slows down to a velocity of 10 km/s. This rather long lifetime implies that there could be up to several tens of active GRB remnants in each galaxy at any given time. For many years, radio observations have revealed the enigmatic presence of expanding neutral-hydrogen (HI) supershells of kpc radius in the Milky Way and in other nearby galaxies. The properties of some supershells cannot be easily explained in terms of conventional sources such as stellar ...

Energy Technology Data Exchange (ETDEWEB)

Ex situ and in situ fuel cell degradation of a sPAEK membrane were investigated. Post-mortem analyses of the aged membrane and of the degradation products eluted in water were carried out by NMR, IR, SEC and EDX. Ex situ agings were performed in a low concentration H{sub 2}O{sub 2} solution (0.07%) without any metallic catalyst. We exemplify that ex situ accelerated aging tests in such hydrogen peroxide solution are relevant to the chemical degradation in fuel cell. We have shown that a 500 h fuel cell test at moderate temperature (60 C) induces significant modifications on the macromolecules such as a 40% molecular weight reduction. Degradation appears heterogeneous and limited to the cathode side. The model compound approach developed in the previous article (Perrot et al.) has allowed the identification of the aging path in fuel cell. Phenolic and carboxylic acid chain ends have been identified as the main products resulting from polymer chain scissions. The ex situ ...

Energy Technology Data Exchange (ETDEWEB)

Wind power is an increasingly significant renewable energy resource, producing no environmentally damaging CO2 emissions. The efficient production of electricity by wind turbines relies on aerodynamics. Aerodynamics of Wind Turbines provides the fundamental solutions to efficient wind turbine design. Following a historical introduction, Part 1 of Aerodynamics of Wind Turbines is concerned with basic rotor aerodynamics, while Part 2 deals with structural aspects of the wind turbine and calculation of the loads on it. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. Aerodynamics of Wind Turbines is an essential reference for both engineering students and others ...

Science.gov (United States)

Varying load can cause changes in a measured gearbox vibration signal. However, conventional techniques for fault diagnosis are based on the assumption that changes in vibration signal are only caused by deterioration of the gearbox. There is a need to develop a technique to provide accurate state indicator of gearbox under fluctuating load conditions. This paper presents an approach to gear fault diagnosis based on complex Morlet continuous wavelet transform under this condition. Gear motion residual signal, which represents the departure of time synchronously averaged signal from the average tooth-meshing vibration, is analyzed as source data due to its lower sensitiveness to the alternating load condition. A fault growth parameter based on the amplitude of wavelet transform is proposed to evaluate gear fault advancement quantitatively. We found that this parameter is insensitive to varying load and can correctly indicate early gear fault. For a comparison, the advantages and ...

International Nuclear Information System (INIS)

At 650"0C, the low-cycle fatigue life was essentially the same for the two alloys on the basis of strain amplitude, but Alloy 800H had a longer life on the basis of stress amplitude. A 500"0C, Alloy 800 and 800H exhibited longer fatigue lifetime than at 650"0C, with Alloy 800 exhibiting a 2-3 times longer life than Alloy 800H when compared on the basis of plastic strain range, whereas the difference was less pronounced when compared on the basis of stress amplitude. When a creep effect was introduced either by way of a hold time or a reduced frequency, Alloy 800 exhibited a greater reduction in life than did Alloy 800H. The dislocation structure changed from planar to cellular with increase in strain range, and extensive precipitation of M_2_3C_6 was noted within the grains for Alloy 800H and along grain boundaries for both alloys. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

A scheme of evaluating a generalized three-photon excitation cross section sigma/sub (3)/ in neutral atomic argon at 3144.67 A is outlined. Three photons at this wavelength can excite the neutral argon atoms from the ground 3p/sup 6/ /sup 1/S/sub 0/ state to the 3p/sup 5/4s'(1/2)/sub 1//sup 0/ state. The fourth photon will ionize the argon atoms. Assuming linear polarization of the incident laser radiation, contributions from several channels in various energy-level schemes are summed in the evaluation of the transition probability. For a laser linewidth of ..delta..lambda/sub L/ = 1 A, our maximum numerical value of the computed result for the three-photon excitation cross section is sigma/sub (3)/ = 1.414 x 10/sup -80/ cm/sup 6/ s/sup 2/. .AE

International Nuclear Information System (INIS)

Development of techniques for separating isomeric nuclides is important to the investigation of schemes for gamma-ray lasers. In preparation for an experiment to separate 10_1_4 atoms of the /sub 197m/Hg (299 keV, tau/sub 1/2/ = 24 hours) isomer, we report isotopically selective resonance ionization of mercury atoms. This has been accomplished by three-step excitation via the 6_3P"1 and 8_1S"0 excited states, using three collinear pulsed laser beams of 254, 286, and 532 nm wavelengths from a Nd:YAG and two dye lasers. These beams were passed through a closed mercury-vapor cell containing electrostatic plates to which the ions were drawn. Ion current and fluorescent radiation were measured as a function of laser frequency. Hyperfine structures for the 254- and 286-nm transitions were observed.

Energy Technology Data Exchange (ETDEWEB)

The transients involved in the reaction of tetracycline (TC) with reducing radicals such as e{sub aq}{sup -}, (CH{sub 3}){sub 2}COH and CO{sub 2}{sup .-}have been characterized by the pulse radiolysis technique. The semi-reduced species formed ({lambda}{sub max} = 630 nm, {epsilon} 3.4 x 10{sup 3} dm{sup 3} mol{sup -1} cm{sup -1}) has been found to be a strong reductant with reduction potential lying in the range -0.450 to -1.40 V vs NHE. TC reacts with e{sub aq}{sup -} at diffusion-controlled rates and the rate constant, depending upon the ionic form of TC existing at a particular pH, varies from 1.2 x 10{sup 10} to 2.8 x 10{sup 10} dm{sup 3} mol{sup -1} s{sup -1}. Based on these results a plausible site of electron addition has been suggested. Reaction of H atoms with TC gives rise to a transient which exhibits spectral and kinetic features different from that of semi-reduced species. (author).

International Nuclear Information System (INIS)

Current advanced CMOS source/drain engineering involves the use of amorphizing implants with 3D geometry. Upon annealing, the induced transient enhanced diffusion (TED) can only be accurately predicted if the amorphized region is correctly modeled, as well as the formation and evolution of extended defects, particularly 3 1 1's and dislocation loops. In addition to the extended defects, already modeled in the atomistic kinetic Monte-Carlo simulator DADOS, we have developed a physically based modeling approach for the implant-induced damage build-up, amorphization and recrystallization, suitable to handle device-size process simulation. It is based on amorphous pockets (3D, irregular shape agglomerates of an arbitrary number of interstitials and vacancies, plus trapped impurities) with a size-dependent activation energy for recombination. The model is able to reproduce experimental aspects like the crystal-amorphous transition temperature and ...

Science.gov (United States)

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its scattering length to be controlled without ...

International Nuclear Information System (INIS)

Complete text of publication follows. The stability regime of the incommensurate phase of quartz is influenced by uniaxial stress. Hence, the phase transition can be induced under isothermal conditions by the application of external mechanical forces. Using real-time neutron scattering the time evolution of structural changes is investigated id detail during stress variations. The time dependent behaviour of the satellite reflection is compared with that one of the fundamental Bragg reflection which - via primary extinction - gives information about the perfection of the crystal. On increasing stress the perfection of the lattice is destroyed immediately while the modulated structure is built up with a delay of about 1 s. Decreasing the stress leads to a reverse behaviour. Moreover, there is evidence that under periodical load residual non-relaxed strain fields survive leading to a different temperature dependence as compared to static ...

British Library Electronic Table of Contents (United Kingdom)

Physicochemical and benthos data were collected from 12 marine monitoring stations in Daya Bay, during 2001-2004. 12 stations in Daya Bay could be grouped into three clusters: cluster I consisted of stations in the southern part of Daya Bay (stations S1, S2 and S6); cluster II consisted of stations in the cage culture areas (stations S3, S4, S5 and S8); cluster III consisted of stations in the southwest, the middle and the northeast of the Bay (stations S7, S9, S10, S11 and S12). Calculation with bivariate correlations between benthos and major physicochemical factors showed that the density of benthos in all stations correlated positively with temperature, DO, pH, NH4-N, SiO3-Si, SiO3-Si /PO4-P and chlorophyll a and was negatively correlated with salinity, Secchi, COD, NO3-N, NO2-N, TIN, ...

Energy Technology Data Exchange (ETDEWEB)

High temperature deformation behavior of AZ31 Mg alloy was investigated in this study on the basis of a processing map ({epsilon} {approx} 0.6). To construct a processing map, compression tests were carried out at various temperatures and strain rates. Two regions of high deformation efficiency ({eta}) were identified as: (1) a dynamic recrystallization (DRX) domain at 250 C and 1/s and (2) a superplasticity domain at 450 C and 10{sup -4}/s. The average grain size observed in the DRX region was considerably smaller (2.9{mu}m) than in any other region. In the superplastic condition, tensile elongation to failure approached to 1040%. At the high Z regions, flow softening occurred resulting from the dynamic recrystallization but below 10{sup 10} of Z value, flow hardening occurred due to the grain growth. Possible deformation mechanisms operating at high temperature were discussed in relation to the activation energy. A two-stage deformation ...

International Nuclear Information System (INIS)

Enthalpy increment measurements on La_2Te_3O_9(s) and La_2Te_4O_1_1(s) were carried out using a Calvet micro-calorimeter. The enthalpy values were analyzed using the non-linear curve fitting method. The dependence of enthalpy increments with temperature was given as: H"o(T) - H"o(298.15 K) (J mol"-"1) = 360.70T + 0.00409T "2 + 133.568 x 10"5/T - 149 923 (373 #<=# T (K) #<=# 936) for La_2Te_3O_9 and H"o(T) - H"o(298.15 K) (J mol"-"1) = 331.927T + 0.0549T "2 + 29.3623 x 10"5/T - 114 587 (373 #<=# T (K) #<=# 936) for La_2Te_4O_1_1.

Energy Technology Data Exchange (ETDEWEB)

Rotationally resolved spectra of kinetic energy releases epsilon-c in predissociations of H/sub 2/, after dissociative charge exchange of H/sub 2/ /sup +/ with Cs atoms, are obtained. The experiments are performed with natural and with pure parahydrogen. The predissociations with epsilon-c<1.9 eV constitute less than 5% of the total amount of dissociations to HXchemically bondH at a beam energy of 5 keV. All strong rotational peaks observed could be attributed to n = 3 Rydberg states which predissociate to H(1s)+H(2l). Vibrational-rotational series are observed of the d /sup 3/Pi/sub u//sup +/, D /sup 1/Pi/sub u//sup +/, and J /sup 1/..delta../sub g//sup +/ states. Predissociation by barrier tunneling is reported of v = 4 levels of the h /sup 3/..sigma../sub g//sup +/ state and of v = 4 and 5 levels of the i /sup 3/Pi/sub g/ state. Selectivity of the charge-exchange process for different n = 3 states, or even for different parity states, is ...

CERN Document Server

Let $M$ be a complex manifold of complex dimension $n+k$. We say that the functions $u_1,...s,u_k$ and the vector fields $\\xi_1,...,\\xi_k$ on $M$ form a \\emph{complex gradient system} if $\\xi_1,...,\\xi_k,J\\xi_1,...,J\\xi_k$ are linearly independent at each point $p\\in M$ and generate an integrable distribution of $TM$ of dimension $2k$ and $du_\\alpha(\\xi_\\beta)=0$, $\\d^c\\u_\\alpha(\\xi_\\beta)=\\delta_{\\alpha\\beta}$ for $\\alpha,\\beta=1,...,k$. We prove a Cauchy theorem for such complex gradient systems with initial data along a $\\CR-$submanifold of type $(\\CRdim,\\CRcodim)$. We also give a complete local characterization for the complex gradient systems which are \\emph{holomorphic} and \\emph{abelian}, which means that the vector fields $\\xi_\\alpha^c=\\xi_\\alpha-J\\xi_\\beta$, $\\alpha=1,...,k$ are holomorphic and satisfy $[\\xi_alpha^c,\\bar{\\xi_\\beta^c}]=0$ for each $\\alpha,\\beta=1,...,k$.

International Nuclear Information System (INIS)

A transient-enhanced diffusion has been observed during the furnace or rapid thermal annealing of As-implanted Si. The relations of the enhanced diffusion to residual defects and lattice restoration have been studied in detail. The As concentration profiles and residual defects are measured. It is found from the data that the lattice has been restored when the implanted sample is annealed at 1150 deg C (or 1050 deg C) for 1s. The defect density decreases rapidly with increase of annealing time (from 1 to 12s). The enhanced diffusion coefficient maximum appears in the annealing time ranging from 1 to 5s. Allmost a 'complete' annealing of displacemet damage is obtained and the diffusion coefficient is less than that in above-mentioned conditions when the implanted samples are annealed at 1150 deg C in the time ranging from 12 to 20s. the mechanism of lattice restoration and enhanced diffusion in annealing process have been discussed.

Energy Technology Data Exchange (ETDEWEB)

This dissertation describes a measurement of the rate ofnuclear muon capture by the proton, performed by the MuCap Collaborationusing a new technique based on a time projection chamber operating inultraclean, deuterium-depleted hydrogen gas at room temperature and 1 MPapressure. The hydrogen target's low gas density of 1 percent compared toliquid hydrogen is key to avoiding uncertainties that arise from theformation of muonic molecules. The capture rate was obtained from thedifference between the mu- disappearance rate in hydrogen--as determinedfrom data collected in the experiment's first physics run in fall2004--and the world averagefor the mu+ decay rate. After combining theresults of my analysis with the results from another independent analysisof the 2004 data, the muon capture rate from the hyperfine singlet groundstate of the mu-p atom is found to be Lambda_S = 725.0 +- 17.4 1/s, fromwhich the induced pseudoscalar ...

Energy Technology Data Exchange (ETDEWEB)

Vacuum arc with cathode spots on the cold electrode is widely used as a plasma generator in a such kind of devices like metal ion sources, plasma cathode electron guns, thing films deposition facilities and others. Most vacuum arc devices utilize a high voltage discharge across an insulator surface to provide a trigger plasma which in turn initiates the main arc discharge. Operation of vacuum arc in a repetitively pulsed mode required a stable triggering system for the long time. But with a discharge across the insulators the number of stable pulses is limited by 100,000 or little bit more. The better method for vacuum arc ignition is low pressure discharge. As shown in this paper it is possible to increase the lifetime of the ignition system in 10 times at least, but negative characteristic of this system is a relatively high pressure (about 0.1 mtorr). In some kinds of vacuum arc applications it is impermissible because it leads to the ...

International Nuclear Information System (INIS)

In the framework of spallation neutron sources and accelerator-driven systems, the international PISA (Proton-induced Spallation) collaboration has initiated measurements of total- and double-differential cross-sections for products of spallation reactions in a wide range of target nuclei (GU) at the COSY proton accelerator in Julich (Germany). The purpose is to study secondary particle production created in structural, window and target materials via proton beams up to 2.5 GeV of incident kinetic energy. Residual nuclei [H, He up to intermediate mass fragment (IMF)] production cross-sections are of great importance for estimating the damage to target and structure materials involving the planned spallation neutron sources, given that the lifetime of window and target materials is directly associated to those cross-sections. The demand for reliable theoretical predictions on production cross-sections is by no means satisfied by the models and codes that are ...

Energy Technology Data Exchange (ETDEWEB)

The ortho-metalated Pt(II) complexes Pt(ppy)(CO)Cl (1), Pt(ptpy)(CO)Cl (2), and Pt(ppy)(Hppy)Cl (3) (where ppy and ptpy are respectively the ortho-C-deprotonated forms of 2-phenylpyridine and 2-p-tolylpyridine and Hppy is 2-phenylpyridine) have been prepared. The CO ligand is coordinated trans to the nitrogen atom of the ortho-metalated ligand and exerts a strong trans effect resulting in a relatively long Pt-N bond [2.114(19) {angstrom}]. This structure shows both the bidentate ppy ligand and the monodentate Hppy with the nitrogens of these ligands trans to each other. The UV/vis electronic absorption spectra of 1-3 have intense bands in the near-UV region ({approximately}375 nm) which have been assigned as metal to ligand charge transfer (MLCT) transitions, and higher energy bands were assigned as ligand-centered transitions. Each complex exhibits relatively long-lived structured emissions in the solid state at ambient temperature and at 77 K and 77 K glassy toluene solutions. These ...

International Nuclear Information System (INIS)

Success in geothermal development can be defined as the ability to produce geothermal energy at compatible energy prices to other energy sources. Drilling comprises usually the largest cost in geothermal development, and the results of drilling is largely influencing the final price of geothermal energy. For 20 geothermal fields with operating power plants, the ratio between installed capacity and the total number of well in the field is 1.9 MWe/well. The drilling history in 30 geothermal fields are analyzed by plotting the average cumulative well outputs as function of the number of wells drilled in the field. The range of the average well output is 1-10 MWe/well with the mean value 4.2 MWe/well for the 30 geothermal fields studied. A leaning curve is defined as the number of wells drilled in each field before the average output per well reaches a fairly constant value, which is characteristic for the geothermal reservoir. The range for this learning time is 4-36 wells and the average ...

Energy Technology Data Exchange (ETDEWEB)

This study focuses on a series of Pt{sup II}(L-L{prime})(dppm){sup n+} complexes, where dppm is bis(diphenylphosphino)methane and L-L{prime} are C(caret)C{prime} (n = 0), C(caret)N (n = 1), and N(caret)N{prime} (n = 2) aromatic ligands. Structural characteristics are reported. Structural features indicate that the Pt-C bond distance is shorter than the Pt-N bond distance in symmetrical complexes and that the Pt-P bond distance trans to N is shorter than the Pt-P bond trans to C. This is consistent with the {sup 31}P NMR spectra where the chemical shift of the P trans to C is {approximately}10 ppm less than found for P trans to N. The energy maxima of the metal-to-ligand charge-transfer band for the complexes containing various L-L{prime} ligands occur in the near-UV region of the spectrum and fall into the energy series bpy > bph > phen > 2-phpy > 2-ptpy > 2-phq > 7,9-bzq, where bpy is 2,2{prime}-bipyridine, 2-phpy is 2-phenylpyridine, 2-ptpy ...

Energy Technology Data Exchange (ETDEWEB)

Restructured power markets require concepts not only for extending the lifetime of existing plants, but also concepts for reducing the life-cycle costs of existing older steam power plants in order to remain competitive with the most modern and advanced power generation technology such as combined cycle power plants. Out of the broad range of methods to extend service life and increase availability, and to increase power output and efficiency, this paper focuses on full repowering. Full repowering replaces the old fired boiler with gas turbine(s) and heat-recovery steam generators (HRSG) as heat input to the existing bottoming cycle and reuses the steam turbine (ST) condenser and further balance of plant (BOP) equipment. The potential offered by this concept is demonstrated. Repowering and modernization projects are executed if they result in economic benefits for the operator. Investment decisions need to be prepared based on an estimate or proof of an adequate ...

Energy Technology Data Exchange (ETDEWEB)

The full text follows. A thermal neutron imaging facility (TNIF) capable of real time neutron radiography and computed tomography was developed for the University of Texas TRIGA Mark II (UT-TRIGA) reactor from 1994-1998. The facility was developed with a through reactor beam port capable of producing a 5.2 x 10{sup 6} n/cm{sup 2}/s thermal neutron flux with a gamma dose rate of less than 1 mR/s after collimation. The original TNIF included the UT-TRIGA reactor, neutron collimation array, sample positioning system, neutron image intensifier tube, video camera, computerized image acquisition system, and a radiation shield. A 0.7 mm slit in cadmium was easily detectable using neutron radiography, and 1.4 mm diameter holes bored in an aluminum block were easily resolved using computed neutron tomography. Precise lower limits of the system resolution have hot been determined. The TNIF is currently being revamped to begin work with the non-destructive evaluation (NDE) of carbon fiber ...

Energy Technology Data Exchange (ETDEWEB)

The atmospheric chemical behaviour of 2H-Heptafluoropropane (CF[sub 3]CHFCF[sub 3], HFC-227) with respect to its rate and mechanism of degradation in the troposphere has been investigated. The rate coefficient for the reaction of HFC-227 with OH radicals has been determined in direct time resolved experiments using a combination of laser-pulse initiation and LIF. In the temperature range T=298-463 K the Arrhenius expression k(T)=(3.8[+-]0.8) 10[sup -13] exp(-1596[+-]77 K/T) cm[sup 3]/s, which corresponds to k (298 K) = (1.8[+-]0.3) 10[sup -15] cm[sup 3]/s, was found. The mechanism of the atmospheric degradation of HFC-227 has been investigated using both, laser-pulse initiated/time resolved and UV photolysis/FTIR product studies. It is concluded that the major carbonyl products are CF[sub 3]COF and CF[sub 2]O which result from the decomposition of the oxy radical CF[sub 3]CF(O)CF[sub 3] by C-C bound fission. The rate coefficient for this decomposition process has been determined to be ...

Energy Technology Data Exchange (ETDEWEB)

A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of {sup 137}Cs from aqueous tank wastes. Two of these materials are organic resins; a phenol-formaldehyde resin (Duolite CS-100) produced by Rohm and Haas Co. (Philadelphia, Pennsylvania) and a resorcinol-formaldehyde (RF) resin produced by Boulder Scientific Co. (Mead, Colorado). One of the key parameters in the assessment of the organic based ion exchange materials is its useful lifetime in the radioactive and chemical environment that will be encountered during waste processing. The focus of the work presented in this report is the radiation stability of the CS-100 and the RF resins. The scope of the testing included one test with a sample of the CS-100 resin and testing of two batches of the RF resin (BSC-187 and BSC-210). Samples of the exchangers were irradiated with a {sup 60}Co ...

International Nuclear Information System (INIS)

A new dirhenium(I) complex fac-[{Re(CO)3(4,7-dinonadecyl-1,10-phenanthro -line)}2 (4,4'-bipyridyl)] (trifluoromethanesulfonate)2 (denoted as D-Re(I) ) is assembled in MCM-41 and SBA-15 type mesoporous silica support. The emission peaks of D-Re(I) in D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are observed at 522 and 517 nm, respectively. Their long excited lifetimes, which are of the order of microseconds, indicate the presence of phosphorescence emission arising from the metal to ligand charge-transfer (MLCT) transition. The luminescence intensities of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 decrease remarkably with increase in the oxygen concentration, meaning that they can be used as optical oxygen sensing materials based on luminescence quenching. The ratios I0/I100 of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are estimated to be 5.6 and 20.1, respectively. The obtained Stern-Volmer oxygen quenching plots of the mesoporous sensing materials could be fitted well to the two-site Demas ...

International Nuclear Information System (INIS)

Nature of tube degradation was studied in support of horizontal steam generator lifetime calculations. Experiments were carried out to evaluate the resistance to environmentally assisted cracking (EAC) of steam generator tubes during operation. Estimations of the incubation period for crack initiation and the threshold K value, K(ISCC), and the crack growth rate were made to predict evolution of damage in tube walls. Experimental results were compared with in-service inspections experience. The paper summarizes results of experiments of C ring specimen for the initiation testing and results of SENT (single edge notch tensile) specimen for the crack growth rate (CGR) testing. The specimens were exposed to concentrated environments at elevated temperatures simulating crevice environments in secondary side crevices in horizontal steam generators. The results show that material of SG (steam generator) tubes is sensitive to transgranular environmentally assisted ...

International Nuclear Information System (INIS)

Brachytherapy refers to short distance treatment of cancer with radiation from small, encapsulated radionuclide sources. This type of treatment is given by placing sources directly into or near the volume to be treated. The dose is then delivered continuously, either over a short period of time (temporary implants) or over the lifetime of the source to a complete decay (permanent implants). This technique is extensively used in the treatments of gynecological, breast, prostate, head and neck, and other soft tissue cancers. The clinical outcomes of this treatment depend on accurate dosimetry and dose delivery. The patient is generally considered to be water equivalent. So the treatment planning system software generally is based on measured or calculated dose distributions in homogenous water medium. In real situation, the treatment volume is not homogenous water medium, but it is a heterogeneous medium consisting of bone, soft tissue, lung, air etc. For better ...

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Understanding the mechanical properties of biomedical devices is critical in predicting and preventing their failure in the body. Such knowledge is essential, for example, in the design of biomedical stents, which must undergo repeated strain over their ten year lifetimes without breaking. Computational models are used to predict mechanical response of a device, but these models are not complete; there are significant deviations from the predictions, especially when devices are subjected to repeated multi-axial loads. Improving these models requires comparisons with actual measurements of strained nitinol. Local measurements of the full strain tensor can be made using X-ray diffraction techniques, but they are currently limited to materials whose grain size is larger than the X-ray beam size or require several diffraction patterns produced by rotation of the sample. Nitinol stents are nanocrystalline, with grains smaller than any available X-ray beam. We present a ...

International Nuclear Information System (INIS)

?-Y(IO3)3 and ?-Y(IO3)3 are transparent until 12.8 and 13.4 ?m, respectively; thus they are interesting as a potential laser matrix in the mid- and beginning of the far-infrared. So, in order to investigate the properties of lanthanides- doped anhydrous yttrium iodate, polycrystalline samples of ?-Y1-xNdx(IO3)3 (0.01?x?0.05), ?-Y1-xNdx(IO3)3 (0.001?x?0.1), ?-Y1-xYbx(IO3)3 (0.01?x?0.33) and ?-Y1-xYbx(IO3)3 (0.01?x?0.25) were synthesized. For Nd3+ ions, fluorescent emissions from the 4F3/2 multiplet were observed at 300 K under pulsed laser excitations at 750 nm and for Yb3+, fluorescent emissions from the 2F5/2 multiplet were observed at 300 K under pulsed laser excitations at 980 nm. The decays of all these emissions were measured. They are exponential and the fluorescence lifetimes are in the range 0.093-0.193 ms for Nd3+ and 0.370-0.541 ms for Yb3+, depending on the nature of the host and the concentration of doping.

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To achieve sufficient thermodynamic efficiency, space nuclear power systems must operate above 1000/sup 0/C. A quantitative evaluation of the existing mechanical properties data for the refractory alloys relevant to space nuclear power systems design lifetimes up to seven years at temperatures up to 1400/sup 0/C is being conducted. The most important properties for space nuclear power systems are long-term high-temperature (>1000/sup 0/C) creep strength and ductility, low-temperature (<400/sup 0/C) fracture toughness (including ductile-to-brittle transition temperature, (DBTT)), and ductility at high strain rates; of special concern are the above properties for weldments of refractory alloys, composition, applied stress, test temperature, test environment (e.g., vacuum, lithium), and thermomechanical treatment (TMT) history. Currently being evaluated are, in order of ascending mp, selected alloys of niobium (e.g., Nb-1% Zr, Nb-1% Zr-0.1% C), molybdenum (e.g., ...

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A study has been made of the reaction [sup 86]Kr + [sup 63]Cu at incident energies of 486, 550, 640, and 730 MeV. Measurements include cross sections, angular distributions, and energy spectra for light charged particles ([sup 1,2,3]H and [sup 4]He), intermediate mass fragments (IMF) (4 [le] Z [le] 17), and heavy fragments (Z [ge] 18). Coincidences between light charged particles and between particles and fragments have been measured to obtain cross sections, energy spectra, and angular distributions. Statistical model analysis of the energy spectra for [sup 1]H and [sup 4]He detected in coincidence with the fragments has allowed estimation of [sup 1]H and [sup 4]He multiplicities associated with the evaporation residues, fragments, and composite nuclei prior to scission. A comparison of cross sections, energy spectra, angular distributions, and particle multiplicities for these matched entrance channels has provided the means for a detailed test of the Bohr Independence Hypothesis. ...

International Nuclear Information System (INIS)

For the lifetime evaluation of plasma facing materials in fusion experimental machines, it is essential to investigate their surface behavior and their temperature responses during an off-normal event such as the plasma disruptions. An infrared thermometer with a sampling speed as fast as 1x10"-"6 s/data, namely, the high-speed infrared thermometer (HSIR), has been developed by the National Research Laboratory of Metrology in Japan. To evaluate an applicability of the newly developed HSIR on the surface temperature measurement of plasma facing materials, high heat flux beam irradiation experiments have been performed with three different materials under the surface heat fluxes up to 170 MW/m"2 for 0.04 s in a hydrogen ion beam test facility at the Japan Atomic Energy Research Institute. As for the results, HSIR can be applicable for measuring the surface temperature responses of the armor tile materials with a little modification. It is also confirmed that surface ...

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This thesis is concerned with the crystallisation behaviour of polymers near to a free surface or a buried interface. The properties of polymers are expected to differ significantly near to an interface (either with air or another polymer), due to the contributions of (a) chain configurations induced at the interface, and (b) different mobilities between interfacial regions and the bulk of the sample. For a semi-crystalline polymer, properties such as the degree of crystallinity and the crystallisation kinetics may be enhanced near to a free surface. Grazing incidence x--ray diffraction (GIXD) is used to investigate such effects in poly(ethylene terphthalate) (PET), showing that a lower crystallisation temperature is obtained at the surface, and the crystallisation kinetics are faster at the surface for all temperatures. It is proposed that in thin films of PET, this surface-induced ordering provides nucleation sites for crystallisation in the bulk. GIXD is also used to investigate the ...

International Nuclear Information System (INIS)

This report summarizes work performed by Argonne National Laboratory (ANL) on fatigue and environmentally assisted cracking (EAC) in light water reactors (LWRs) during the six months from October 1993 to March 1994. EAC and fatigue of piping, pressure vessels, and core components in LWRs are important concerns in operating plants and as extended reactor lifetimes are envisaged. Topics that have been investigated include (a) fatigue of low-alloy steel used in piping, steam generators, and reactor pressure vessels, (b) EAC of wrought and cast austenitic stainless steels (SSs), and (c) radiation-induced segregation and irradiation-assisted stress corrosion cracking (IASCC) of Type 304 SS after accumulation of relatively high fluence. Fatigue tests have been conducted on A302-Gr B low-alloy steel to verify whether the current predictions of modest decreases of fatigue life in simulated pressurized water reactor water are valid for high-sulfur heats that show ...

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Two mechanical design requirements are defined for the SSC Collider beam tube. First, the vacuum requirement (luminosity lifetime = 150 hrs). It requires the design of a pressure boundary within the cold mass vessel to provide a vacuum tunnel for the proton beam and to minimize the synchrotron radiation gas desorbtion with a suitable material. The Collider beam tube design is under an intensive activity to search for a material that will meet the luminosity requirement without a distributed pump or liner. Second is the tube wall`s resistivity requirement ({sigma}*t = 2E5 {Omega}{sup {minus}1}). For a 4.2 K beam tube the Cu thickness is 100 {mu}m (RRR=30,6.7 T, {sigma}=2E9{Omega}{sup {minus}1}m{sup {minus}1}). The copper yield strength is relatively low in comparison to steel and, therefore, the design of the steel layer is governed by the copper layer yield stress limit. A beam tube subjected to eddy current load in a quenching dipole requires an optimum diameter ...

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The objective of this study is to evaluate the lifetime of Zr-2.5Nb pressure tube at Wolsung Unit-1. The testing materials (Effective full power year: 9.3 year, Accumulated nuetron fluence: 7.66{approx}8.91 x 1025 n/m{sup 2}) were sampled from M-11 tube at various position(inlet, middle and outlet). The cutting was carried out at hot cell to fabricate CT(Compact tension) specimen with 48 ppm hydrogen content. In the result of DHC test, irradiation-damaged specimen showed 4{approx}6 times faster DHC velocity(5.298E-0.8{approx}7.039E-8 m/s: 182 .deg. C) than non-irradiated specimen. These DHCV results also show slight faster than one of specimen from Pickering plant (average DHCV: 4.5E-8 m/s: 182 .Deg C). This faster DHCV can be explained with the fact that Wolsung Unit-1 have been operated in a severe conditions(higher cooling water temperature, high power and efficiency) than Pickering one. The striation spacing which was seen DHC fracture surface at irradiated ...

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The Alloy 800 tubes used in CANDU 6 steam generators have not experienced significant corrosion damage to date, which may be attributed to successful water chemistry control strategies. However, it is known that Alloy 800, like other steam generator (SG) tubing materials, is not immune to corrosion, especially pitting, under some plausible but off-specification operating scenarios. Electrochemical measurements provide information on corrosion susceptibility and rate, which are known to be a function of water chemistry. Using laboratory data in combination with chemistry monitoring and diagnostic software it is possible to assess the impact of plant operating conditions on SG tube corrosion for plant life management (PLIM). In this context, this paper discusses the results of electrochemical measurements made to elucidate the corrosion behaviour of Alloy 800 SG tubes under conditions simulating those plausible in SG crevices. In addition to crevice pH, the influence of PbO, acting alone ...

International Nuclear Information System (INIS)

In light of the recent rapid increase in the fossil fuel prices it is meaningful to evaluate the impact of these price changes in the economics of dual-purpose desalination projects producing electricity and fresh water simultaneously. The price of crude oil and LNG (Liquefied Natural Gas) has increased by about 200% and 100% during the past three or four years. The uranium price has also increased by nearly 500% during the same period. The purpose of this paper is to analyze and compare the economics of SMART (System-integrated Modular Advanced ReacTor) which is being developed as a small size PWR type and the LNG Combine Cycle coupled with MED (Multi-Effect Distillation) which are being acknowledged as promising energy sources for the future in Korea. The methods of analysis used in this paper are the lifetime leveled cost method for the power and water cost calculation and the power credit method for the total cost allocation. DEEP (Devaluation Economic ...

International Nuclear Information System (INIS)

In order to predict or to evaluate the structural reliability of a variety of nuclear components under actual changing operating conditions, it is necessary to take the detailed geometrical features of components into consideration on one hand, and thermo-mechanical loading conditions with space and time variations during the lifetime, on the other hand. This consideration leads the authors to develop a super large-scale structural analysis program based on a parallel computational FEM with a variable scale of PC cluster architecture, whose prototype system is presented in a companion paper in this Symposium. Development of the PC cluster technology is one of the most important subjects in large-scale structural simulation, reducing computer costs and thus making simulation more acceptable to the engineering community. This paper presents the developmental status of the parallel FEM solver, demonstrating computational capabilities with three dimensional effects ...

Energy Technology Data Exchange (ETDEWEB)

This thesis examines the design of a propulsion system for a series hybrid vehicle and includes the study of an energy storage unit using double-layer capacitors and a lightweight soft-switched converter system, and two new components in series hybrid vehicles. The development of environmentally sustainable vehicles is more urgent now given the fact that pollution levels are ever increasing. No electric vehicle has yet been developed that can compete with a normal vehicle based only on internal combustion engines. The dilemma lies in the difficulty of storing the amount of energy needed and supply it a high power levels. An attractive and viable option to reducing pollution and maintaining good performance may lie in hybrid electric-powered vehicles. The double-layer power capacitors are an interesting option because of their high power density and long lifetime. The devices are new and assembling large energy storage units must be thoroughly examined before using ...