WorldWideScience

Sample records for metallization lifetime prediction

  1. Filter replacement lifetime prediction

    Science.gov (United States)

    Hamann, Hendrik F.; Klein, Levente I.; Manzer, Dennis G.; Marianno, Fernando J.

    2017-10-25

    Methods and systems for predicting a filter lifetime include building a filter effectiveness history based on contaminant sensor information associated with a filter; determining a rate of filter consumption with a processor based on the filter effectiveness history; and determining a remaining filter lifetime based on the determined rate of filter consumption. Methods and systems for increasing filter economy include measuring contaminants in an internal and an external environment; determining a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling; determining a cost of increased air pressure to filter external air; and if the cost of filtering external air exceeds the cost of the corrosion rate increase, increasing an intake of unfiltered external air.

  2. The possibility of prediction of the lifetime of metallic nuclear fuel elements in a radiation field of thermal nuclear reactors

    International Nuclear Information System (INIS)

    Livne, Z.; Ramon, P.

    1979-01-01

    An attempt is made to clarify the possible causes of failure of irradiated nuclear fuel cartridges, in order to determine the parameters which govern the lifetime of the fuel and a way to predict it. Measurements of mechanical properties of irradiated uranium metal and cladding, can serve as a basis for failure prediction. Testing irradiated fuel elements by bending till fracture enables to evaluate the integral character of the fuel element, along the cross-section, taking into account the difference in brittleness of several zones. It is likely that the bending test, which indicates the behaviour of a stress-strain function, is a faster and more reliable way to determine the mechanical properties of irradiated nuclear fuel. Since the stresses applied to the cladding during irradiation are locally hydrostatic, its postirradiation blow-up provide information on strength and elasticity variations of the irradiated cladding material. (B.G.)

  3. Factors controlling metal fuel lifetime

    International Nuclear Information System (INIS)

    Porter, D.L.; Hofman, G.L.; Seidel, B.R.; Walters, L.C.

    1986-01-01

    The reliability of metal fuel elements is determined by a fuel burnup at which a statistically predicted number of fuel breaches would occur, the number of breaches determined by the amount of free fission gas which a particular reactor design can tolerate. The reliability is therefore measured using experimentally determined breach statistics, or by modelling fuel element behavior and those factors which contribute to cladding breach. The factors are fuel/cladding mechanical and chemical interactions, fission gas pressure, fuel phase transformations involving volume changes, and fission product effects on cladding integrity. Experimental data for EBR-II fuel elements has shown that the primary, and perhaps the only significant factor affecting metal fuel reliability, is the pressure-induced stresses caused by fission gas release. Other metal fuel/cladding systems may perform similarly

  4. Theoretical calculations of positron lifetimes for metal oxides

    International Nuclear Information System (INIS)

    Mizuno, Masataka; Araki, Hideki; Shirai, Yasuharu

    2004-01-01

    Our recent positron lifetime measurements for metal oxides suggest that positron lifetimes of bulk state in metal oxides are shorter than previously reported values. We have performed theoretical calculations of positron lifetimes for bulk and vacancy states in MgO and ZnO using first-principles electronic structure calculations and discuss the validity of positron lifetime calculations for insulators. By comparing the calculated positron lifetimes to the experimental values, it wa found that the semiconductor model well reproduces the experimental positron lifetime. The longer positron lifetime previously reported can be considered to arise from not only the bulk but also from the vacancy induced by impurities. In the case of cation vacancy, the calculated positron lifetime based on semiconductor model is shorter than the experimental value, which suggests that the inward relaxation occurs around the cation vacancy trapping the positron. (author)

  5. Predicting the Lifetimes of Nuclear Waste Containers

    Science.gov (United States)

    King, Fraser

    2014-03-01

    As for many aspects of the disposal of nuclear waste, the greatest challenge we have in the study of container materials is the prediction of the long-term performance over periods of tens to hundreds of thousands of years. Various methods have been used for predicting the lifetime of containers for the disposal of high-level waste or spent fuel in deep geological repositories. Both mechanical and corrosion-related failure mechanisms need to be considered, although until recently the interactions of mechanical and corrosion degradation modes have not been considered in detail. Failure from mechanical degradation modes has tended to be treated through suitable container design. In comparison, the inevitable loss of container integrity due to corrosion has been treated by developing specific corrosion models. The most important aspect, however, is to be able to justify the long-term predictions by demonstrating a mechanistic understanding of the various degradation modes.

  6. Final report on reliability and lifetime prediction.

    Energy Technology Data Exchange (ETDEWEB)

    Gillen, Kenneth T; Wise, Jonathan; Jones, Gary D.; Causa, Al G.; Terrill, Edward R.; Borowczak, Marc

    2012-12-01

    This document highlights the important results obtained from the subtask of the Goodyear CRADA devoted to better understanding reliability of tires and to developing better lifetime prediction methods. The overall objective was to establish the chemical and physical basis for the degradation of tires using standard as well as unique models and experimental techniques. Of particular interest was the potential application of our unique modulus profiling apparatus for assessing tire properties and for following tire degradation. During the course of this complex investigation, extensive relevant information was generated, including experimental results, data analyses and development of models and instruments. Detailed descriptions of the findings are included in this report.

  7. Lifetime of Organic Photovoltaics: Status and Predictions

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Madsen, Morten Vesterager; Roth, Bérenger

    2016-01-01

    The results of a meta-analysis conducted on organic photovoltaics (OPV) lifetime data reported in the literature is presented through the compilation of an extensive OPV lifetime database based on a large number of articles, followed by analysis of the large body of data. We fully reveal the prog......The results of a meta-analysis conducted on organic photovoltaics (OPV) lifetime data reported in the literature is presented through the compilation of an extensive OPV lifetime database based on a large number of articles, followed by analysis of the large body of data. We fully reveal...... the progress of reported OPV lifetimes. Furthermore, a generic lifetime marker has been defi ned, which helps with gauging and comparing the performance of different architectures and materials from the perspective of device stability. Based on the analysis, conclusions are drawn on the bottlenecks...

  8. Accelerated lifetime test of vibration isolator made of Metal Rubber material

    Science.gov (United States)

    Ao, Hongrui; Ma, Yong; Wang, Xianbiao; Chen, Jianye; Jiang, Hongyuan

    2017-01-01

    The Metal Rubber material (MR) is a kind of material with nonlinear damping characteristics for its application in the field of aerospace, petrochemical industry and so on. The study on the lifetime of MR material is impendent to its application in engineering. Based on the dynamic characteristic of MR, the accelerated lifetime experiments of vibration isolators made of MR working under random vibration load were conducted. The effects of structural parameters of MR components on the lifetime of isolators were studied and modelled with the fitting curves of degradation data. The lifetime prediction methods were proposed based on the models.

  9. Positron annihilation lifetime study of low temperature irradiated metals

    Energy Technology Data Exchange (ETDEWEB)

    Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1997-11-01

    Positron annihilation lifetime measurements have been made for electron and neutron irradiated Fe, Fe-Cr, Fe-Cu, Fe-Si, Fe-16Cr-17Ni specimens, and isochronal annealing behaviors were obtained for these metals and alloys. It was found that vacancies start to migrate at about 200 K in Fe and form microvoids, but by the addition of small amount of alloying elements this behavior was changed depending on the alloying elements. Positron lifetime calculations were made to explain the experimental results using EAM (embedded atom method) type potential for the lattice relaxation and the atomic superposition method for the lifetime calculation. Fairly good agreements were obtained for the positron lifetime in a vacancy in Fe and other alloys. (author)

  10. Improving, characterizing and predicting the lifetime of organic photovoltaics

    DEFF Research Database (Denmark)

    Gevorgyan, Suren A.; Heckler, Ilona Maria; Bundgaard, Eva

    2017-01-01

    This review summarizes the recent progress in the stability and lifetime of organic photovoltaics (OPVs). In particular, recently proposed solutions to failure mechanisms in different layers of the device stack are discussed comprising both structural and chemical modifications. Upscaling...... characterization reported recently. Lifetime testing and determination is another challenge in the field of organic solar cells and the final sections of this review discuss the testing protocols as well as the generic marker for device lifetime and the methodology for comparing all the lifetime landmarks in one...... common diagram. These tools were used to determine the baselines for OPV lifetime tested under different ageing conditions. Finally, the current status of lifetime for organic solar cells is presented and predictions are made for progress in the near future....

  11. Predicting sample lifetimes in creep fracture of heterogeneous materials

    Science.gov (United States)

    Koivisto, Juha; Ovaska, Markus; Miksic, Amandine; Laurson, Lasse; Alava, Mikko J.

    2016-08-01

    Materials flow—under creep or constant loads—and, finally, fail. The prediction of sample lifetimes is an important and highly challenging problem because of the inherently heterogeneous nature of most materials that results in large sample-to-sample lifetime fluctuations, even under the same conditions. We study creep deformation of paper sheets as one heterogeneous material and thus show how to predict lifetimes of individual samples by exploiting the "universal" features in the sample-inherent creep curves, particularly the passage to an accelerating creep rate. Using simulations of a viscoelastic fiber bundle model, we illustrate how deformation localization controls the shape of the creep curve and thus the degree of lifetime predictability.

  12. Reliability and lifetime predictions of SLC klystrons

    International Nuclear Information System (INIS)

    Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Lee, T.G.; Vlieks, A.E.

    1989-01-01

    The energy upgrade of SLAC, with the first of the new 67 MW SLAC Linear Collider (SLC) klystrons, began over four years ago. Today there are over 200 of these klystrons in operation. As a result, there is a wealth of klystron performance and failure information that enables reasonable predictions to be made on life expectancy and reliability. Data from initial tests, follow-up tests and daily operation monitoring on the accelerator is stored for analysis. Presented here are life expectancy predictions with particular emphasis on cathode life. Also, based on this data, the authors will discuss some of the principal modes of failure. 3 refs., 2 figs., 1 tab

  13. Reliability and lifetime predictions of SLC klystrons

    International Nuclear Information System (INIS)

    Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Lee, T.G.; Vlieks, A.E.

    1989-03-01

    The energy upgrade of SLAC, with the first of the new 67 MW SLAC Linear Collider (SLC) klystrons, began over four years ago. Today there are over 200 of these klystrons in operation. As a result, there is a wealth klystron performance and failure information that enables reasonable predictions to be made on life expectancy and reliability. Data from initial tests, follow-up tests and daily operation monitoring on the accelerator is stores for analysis. Presented here are life expectancy predictions with particular emphasis on cathode life. Also, based on this data, we will discuss some of the principal modes of failure. 3 refs., 2 figs

  14. A lifetime prediction method for LEDs considering mission profiles

    DEFF Research Database (Denmark)

    Qu, Xiaohui; Wang, Huai; Zhan, Xiaoqing

    2016-01-01

    and to benchmark the cost-competitiveness of different lighting technologies. The existing lifetime data released by LED manufacturers or standard organizations are usually applicable only for specific temperature and current levels. Significant lifetime discrepancies may be observed in field operations due...... to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and the statistical properties of the life data...

  15. Metallized Film Capacitor Lifetime Evaluation and Failure Mode Analysis

    CERN Document Server

    Gallay, R.

    2015-06-15

    One of the main concerns for power electronic engineers regarding capacitors is to predict their remaining lifetime in order to anticipate costly failures or system unavailability. This may be achieved using a Weibull statistical law combined with acceleration factors for the temperature, the voltage, and the humidity. This paper discusses the different capacitor failure modes and their effects and consequences.

  16. Predicting Customer Lifetime Value in Multi-Service Industries

    NARCIS (Netherlands)

    A.C.D. Donkers (Bas); P.C. Verhoef (Peter); M.G. de Jong (Martijn)

    2003-01-01

    textabstractCustomer lifetime value (CLV) is a key-metric within CRM. Although, a large number of marketing scientists and practitioners argue in favor of this metric, there are only a few studies that consider the predictive modeling of CLV. In this study we focus on the prediction of CLV in

  17. Adolescent conscientiousness predicts lower lifetime unemployment.

    Science.gov (United States)

    Egan, Mark; Daly, Michael; Delaney, Liam; Boyce, Christopher J; Wood, Alex M

    2017-04-01

    Existing research on Big Five personality and unemployment has relied on personality measures elicited after the respondents had already spent years in the labor market, an experience that could change personality. We clarify the direction of influence by using the British Cohort Study (N = 4,206) to examine whether conscientiousness and other Big Five personality traits at age 16-17 predict unemployment over age 16-42. Our hypothesis that higher conscientiousness in adolescence would predict lower unemployment was supported. In analyses controlling for intelligence, gender, and parental socioeconomic status, the less conscientious (-1 SD) had a predicted probability of unemployment twice as high (3.4% vs. 1.7%) as the highly conscientious (+1 SD), an effect size comparable to intelligence. Mediation analysis revealed that academic motivation and educational attainment explained only 8.9% of this association. Fostering conscientiousness in early life may be an effective way to reduce unemployment throughout adulthood. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  18. Predicting a future lifetime through Box-Cox transformation.

    Science.gov (United States)

    Yang, Z

    1999-09-01

    In predicting a future lifetime based on a sample of past lifetimes, the Box-Cox transformation method provides a simple and unified procedure that is shown in this article to meet or often outperform the corresponding frequentist solution in terms of coverage probability and average length of prediction intervals. Kullback-Leibler information and second-order asymptotic expansion are used to justify the Box-Cox procedure. Extensive Monte Carlo simulations are also performed to evaluate the small sample behavior of the procedure. Certain popular lifetime distributions, such as Weibull, inverse Gaussian and Birnbaum-Saunders are served as illustrative examples. One important advantage of the Box-Cox procedure lies in its easy extension to linear model predictions where the exact frequentist solutions are often not available.

  19. A Lifetime Prediction Method for LEDs Considering Real Mission Profiles

    DEFF Research Database (Denmark)

    Qu, Xiaohui; Wang, Huai; Zhan, Xiaoqing

    2017-01-01

    operations due to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and also the statistical......The Light-Emitting Diode (LED) has become a very promising alternative lighting source with the advantages of longer lifetime and higher efficiency than traditional ones. The lifetime prediction of LEDs is important to guide the LED system designers to fulfill the design specifications...... properties of the life data available from accelerated degradation testing. The electrical and thermal characteristics of LEDs are measured by a T3Ster system, used for the electro-thermal modeling. It also identifies key variables (e.g., heat sink parameters) that can be designed to achieve a specified...

  20. Lifetime prediction of ammunition at TNO Prins Maurits Laboratory

    NARCIS (Netherlands)

    Leenders, A.P.M.; Driel, C.A. van; Klerk, W.P.C. de; Keizers, H.L.J.

    2000-01-01

    TNO-PML is an independent R & D organisation, with the Dutch MoD as its most important customer. In 1993, the ‘Lifetime prediction of ammunition’ research programme, funded by the MoD, was started at TNO-PML. One of the reasons for starting this programme was the economical profit that can be made

  1. Possibility logic applied to pressure vessel residual lifetime prediction

    International Nuclear Information System (INIS)

    Garribba, S.; Lucia, A.C.; Volta, G.

    1985-01-01

    The adequacy is discussed of a probability measure to deal with the different types of uncertainty affecting any pressure vessel lifetime prediction. A more comprehensive framework derived from the fuzzy set theory and including as particular case possibility and probability measures is considered. With reference to the most critical step of lifetime assessment (the ND inspection), the paper compares the results, obtained adopting a possibility measure or a probability measure, in the representation models, fault tree-event tree, and in the decision models

  2. Prediction of the remaining lifetime of stainless steels under conditions of stress corrosion cracking

    International Nuclear Information System (INIS)

    Tandler, M.; Vehovar, L.; Dolecek, V.; Rotnik, U.

    2003-01-01

    The prediction of the lifetime of metal structures and equipment under conditions of stress corrosion is very complicated because of the complexity of this process of degradation. Recently a new method, based on the so-called corrosion elongation curves, has been found, which can be used to predict the time to failure under these conditions. By upgrading of these curves (and thus obtaining Upgraded Corrosion Elongation Curves - UCEC's) it has been possible to obtain a precise definition of the time needed for the initiation of the corrosion crack, and for its stable growth. It is upon this basis that diagrams for the prediction of remaining lifetime (DPRL's) have been developed. DPRL's can also be used to predict the values of various critical parameters which have to be achieved if a stress corrosion crack is to occur. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [de

  3. Predictive Models of Li-ion Battery Lifetime (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G.; Shi, Y.; Pesaran, A.

    2014-09-01

    Predictive models of Li-ion battery reliability must consider a multiplicity of electrochemical, thermal and mechanical degradation modes experienced by batteries in application environments. Complicating matters, Li-ion batteries can experience several path dependent degradation trajectories dependent on storage and cycling history of the application environment. Rates of degradation are controlled by factors such as temperature history, electrochemical operating window, and charge/discharge rate. Lacking accurate models and tests, lifetime uncertainty must be absorbed by overdesign and warranty costs. Degradation models are needed that predict lifetime more accurately and with less test data. Models should also provide engineering feedback for next generation battery designs. This presentation reviews both multi-dimensional physical models and simpler, lumped surrogate models of battery electrochemical and mechanical degradation. Models are compared with cell- and pack-level aging data from commercial Li-ion chemistries. The analysis elucidates the relative importance of electrochemical and mechanical stress-induced degradation mechanisms in real-world operating environments. Opportunities for extending the lifetime of commercial battery systems are explored.

  4. Lifetime prediction of structures submitted to thermal fatigue loadings

    International Nuclear Information System (INIS)

    Amiable, S.

    2006-01-01

    The aim of this work is to predict the lifetime of structures submitted to thermal fatigue loadings. This work lies within the studies undertaken by the CEA on the thermal fatigue problems from the french reactor of Civaux. In particular we study the SPLASH test: a specimen is heated continuously and cyclically cooled down by a water spray. This loading generates important temperature gradients in space and time and leads to the initiation and the propagation of a crack network. We propose a new thermo-mechanical model to simulate the SPLASH experiment and we propose a new fatigue criterion to predict the lifetime of the SPLASH specimen. We propose and compare several numerical models with various complexity to estimate the mechanical response of the SPLASH specimen. The practical implications of this work are the reevaluation of the hypothesis used in the French code RCC, which are used to simulate thermal shock and to interpret the results in terms of fatigue. This work leads to new perspectives on the mechanical interpretation of the fatigue criterion. (author)

  5. Aging and lifetime prediction of O-ring seals

    International Nuclear Information System (INIS)

    Koemmling, Anja

    2017-01-01

    In some applications, elastomer seals have to remain leak tight over extended time periods (up to several decades) as an exchange of the seals is not practical. Therefore, it is necessary to be able to predict the lifetime of such seals reliably. For this reason, ageing experiments with O-rings and sheets based on hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) were performed over up to two years at different temperatures. For investigating the changes of material properties during ageing, measurements of i.a. hardness and tensile behaviour as well as dynamic-mechanical and thermogravimetric analyses were conducted. For assessing the relaxation and recovery behaviour of the ageing seals, compression stress relaxation and compression set experiments were performed. Furthermore, leakage rate was measured to detect seal failure. By examining the aged samples, both the property changes and the responsible degradation mechanisms were characterised. Additionally, the most suitable approach for lifetime predictions should be determined using the large database of results from different test methods performed at several ageing times and temperatures. This included identifying an end-of-lifetime criterion that correlates with leakage and thus seal failure. Regarding the property changes and degradation mechanisms of HNBR, a pronounced embrittlement was observed due to dominant crosslinking reactions during ageing. These also resulted in a decrease of oxygen permeability, leading to a reduction of the oxygen transport into the interior sample (mainly of the thicker O-rings). This resulted in diffusion-limited oxidation effects (DLO effects), meaning that the interior of the sample aged less strongly than regions close to the surface. During ageing of EPDM, both chain scission and crosslinking occurred, which became noticeable in deteriorated tensile properties and decreased compression force as well as

  6. Stress corrosion cracking lifetime prediction of spring screw

    International Nuclear Information System (INIS)

    Koh, S. K.; Ryu, C. H.

    2004-01-01

    A lifetime prediction of holddown spring screw in nuclear fuel assembly was performed using fracture mechanics approach. The spring screw was designed such that it was capable of sustaining the loads imposed by the initial tensile preload and operational loads. In order to investigate the cause of failure and to predict the stress corrosion cracking life of the screw, a stress analysis of the top nozzle spring assembly was done using finite element analysis. The elastic-plastic finite element analysis showed that the local stresses at the critical regions of head-shank fillet and thread root significantly exceeded than the yield strength of the screw material, resulting in local plastic deformation. Normalized stress intensity factors for PWSCC life prediction was proposed. Primary water stress corrosion cracking life of the Inconel 600 screw was predicted by using integration of the Scott model and resulted in 1.78 years, which was fairly close to the actual service life of the holddown spring screw

  7. Barium depletion study on impregnated cathodes and lifetime prediction

    International Nuclear Information System (INIS)

    Roquais, J.M.; Poret, F.; Doze, R. le; Ricaud, J.L.; Monterrin, A.; Steinbrunn, A.

    2003-01-01

    In the thermionic cathodes used in cathode ray-tubes (CRTs), barium is the key element for the electronic emission. In the case of the dispenser cathodes made of a porous tungsten pellet impregnated with Ba, Ca aluminates, the evaporation of Ba determines the cathode lifetime with respect to emission performance in the CRT. The Ba evaporation results in progressive depletion of the impregnating material inside the pellet. In the present work, the Ba depletion with time has been extensively characterized over a large range of cathode temperature. Calculations using the depletion data allowed modeling of the depletion as a function of key parameters. The link between measured depletion and emission in tubes has been established, from which an end-of-life criterion was deduced. Taking modeling into account, predicting accelerated life-tests were performed using high-density maximum emission current (MIK)

  8. A Satellite Mortality Study to Support Space Systems Lifetime Prediction

    Science.gov (United States)

    Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory

    2013-01-01

    Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

  9. Positron lifetime and Moessbauer study of Fe80-xNixB20 metallic glasses

    International Nuclear Information System (INIS)

    Baluch, S.; Miglierini, M.; Groene, R.; Sitek, J.

    1989-01-01

    In order to investigate the short-range order (SRO) of iron-rich Fe 80-x Ni x B 20 (x = 10, 20, 30, 40) metallic glasses positron lifetime and Moessbauer measurements were carried out. Positron lifetimes of samples and Moessbauer hyperfine structure data of neutron-irradiated samples as functions of nickel content are shown and discussed. Results give evidence that high Ni content stabilizes the structure and can be connected with a higher degree of SRO in metallic glasses

  10. The Lifetime Prediction of LED Drivers and Lamps

    NARCIS (Netherlands)

    Sun, B.

    2017-01-01

    Light-Emitting Diodes (LEDs) have become a very promising alternative lighting source with the main advantages of a longer lifetime and a higher efficiency than traditional ones. However, the LED lamp’s lifetime is compromised by its driver’s reliability. Although extensive studies have been made on

  11. New paradigm for prediction of radiation life-time of reactor pressure vessel

    International Nuclear Information System (INIS)

    Kotrechko, S.A.; Meshkov, Yu.Ya.; Neklyudov, I.M.; Revka, V.N.

    2011-01-01

    New paradigm for prediction of radiation life-time of reactor pressure vessel is presented. Equation for limiting state of reactor pressure vessel wall with crack-like defect is obtained. It is exhibited that the value of critical fluence Φ c may be determined not by shift of critical temperature of fracture of surveillance specimen, which is indirect characteristic, but by direct method, namely, by the condition of initiation of brittle fracture of irradiated metal ahead of a crack in RPV wall. Within the framework of engineering version of LA to fracture the technique for Φ c ascertainment is developed. Prediction of Φ c for WWER pressure vessels demonstrates potentialities of this technique.

  12. ''RESURS'' - The Russian scientific-technical programme for NPP equipment lifetime monitoring, estimation, prediction and management

    International Nuclear Information System (INIS)

    Emelyanov, V.

    1994-01-01

    RESURS programme is described implementation of which will allow to work out regulatory-methodological basis providing legal and technical solution of NPP equipment lifetime management, prediction, monitoring and estimation problems

  13. Advanced Models and Controls for Prediction and Extension of Battery Lifetime (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G.; Pesaran, A.

    2014-02-01

    Predictive models of capacity and power fade must consider a multiplicity of degradation modes experienced by Li-ion batteries in the automotive environment. Lacking accurate models and tests, lifetime uncertainty must presently be absorbed by overdesign and excess warranty costs. To reduce these costs and extend life, degradation models are under development that predict lifetime more accurately and with less test data. The lifetime models provide engineering feedback for cell, pack and system designs and are being incorporated into real-time control strategies.

  14. Coupled modeling of the competitive gettering of transition metals and impact on performance of lifetime sensitive devices

    Science.gov (United States)

    Yazdani, Armin; Chen, Renyu; Dunham, Scott T.

    2017-03-01

    This work models competitive gettering of metals (Cu, Ni, Fe, Mo, and W) by boron, phosphorus, and dislocation loops, and connects those results directly to device performance. Density functional theory calculations were first performed to determine the binding energies of metals to the gettering sites, and based on that, continuum models were developed to model the redistribution and trapping of the metals. Our models found that Fe is most strongly trapped by the dislocation loops while Cu and Ni are most strongly trapped by the P4V clusters formed in high phosphorus concentrations. In addition, it is found that none of the mentioned gettering sites are effective in gettering Mo and W. The calculated metal redistribution along with the associated capture cross sections and trap energy levels are passed to device simulation via the recombination models to calculate carrier lifetime and the resulting device performance. Thereby, a comprehensive and predictive TCAD framework is developed to optimize the processing conditions to maximize performance of lifetime sensitive devices.

  15. Analysis of Orbital Lifetime Prediction Parameters in Preparation for Post-Mission Disposal

    Directory of Open Access Journals (Sweden)

    Ha–Yeon Choi

    2015-12-01

    Full Text Available Atmospheric drag force is an important source of perturbation of Low Earth Orbit (LEO orbit satellites, and solar activity is a major factor for changes in atmospheric density. In particular, the orbital lifetime of a satellite varies with changes in solar activity, so care must be taken in predicting the remaining orbital lifetime during preparation for post-mission disposal. In this paper, the System Tool Kit (STK® Long-term Orbit Propagator is used to analyze the changes in orbital lifetime predictions with respect to solar activity. In addition, the STK® Lifetime tool is used to analyze the change in orbital lifetime with respect to solar flux data generation, which is needed for the orbital lifetime calculation, and its control on the drag coefficient control. Analysis showed that the application of the most recent solar flux file within the Lifetime tool gives a predicted trend that is closest to the actual orbit. We also examine the effect of the drag coefficient, by performing a comparative analysis between varying and constant coefficients in terms of solar activity intensities.

  16. Low cycle fatigue lifetime of HIP bonded Bi-metallic first wall structures of fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hatano, Toshihisa; Sato, Satoshi; Furuya, Kazuyuki; Kuroda, Toshimasa; Enoeda, Mikio; Takatsu, Hideyuki [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Hashimoto, Toshiyuki; Kitamura, Kazunori

    1998-10-01

    A HIP bonded bi-metallic panel composed of a dispersion strengthened copper (DSCu) layer and type 316L stainless steel (SS316L) cooling pipes is the reference design of the ITER first wall. To examine the fatigue lifetime of the first wall panel under cyclic mechanical loads, low cycle fatigue tests of HIP bonded bi-metallic specimens made of SS316L and DSCu were conducted with the stress ratio of -1.0 and five nominal strain range conditions ranging from 0.2 to 1.0%. Elasto-plastic analysis has also been conducted to evaluate local strain ranges under the nominal strains applied. Initial cracks were observed at the inner surface of the SS316L cooling pipes for all of the specimens tested, which was confirmed by the elasto-plastic analysis that the maximum strains of the test specimens were developed at the same locations. It was found that the HIP bonded bi-metallic test specimens had a fatigue lifetime longer than that of the SS316L raw material obtained by round bar specimens. Similarly, the fatigue lifetime of the DSCu/SS316L HIP interface was also longer than the round bar test results for the HIP joints. From these results, it has been confirmed that the bi-metallic first wall panel with built-in cooling pipes made by HIP bonding has a sufficient fatigue lifetime in comparison with the raw fatigue data of the materials, which also suggests that the fatigue lifetime evaluation has an adequate margin against fracture if it follows the design fatigue curve based on the material fatigue data. (author)

  17. FPGA implementation of predictive degradation model for engine oil lifetime

    Science.gov (United States)

    Idros, M. F. M.; Razak, A. H. A.; Junid, S. A. M. Al; Suliman, S. I.; Halim, A. K.

    2018-03-01

    This paper presents the implementation of linear regression model for degradation prediction on Register Transfer Logic (RTL) using QuartusII. A stationary model had been identified in the degradation trend for the engine oil in a vehicle in time series method. As for RTL implementation, the degradation model is written in Verilog HDL and the data input are taken at a certain time. Clock divider had been designed to support the timing sequence of input data. At every five data, a regression analysis is adapted for slope variation determination and prediction calculation. Here, only the negative value are taken as the consideration for the prediction purposes for less number of logic gate. Least Square Method is adapted to get the best linear model based on the mean values of time series data. The coded algorithm has been implemented on FPGA for validation purposes. The result shows the prediction time to change the engine oil.

  18. Lifetime predictions for the Solar Maximum Mission (SMM) and San Marco spacecraft

    Science.gov (United States)

    Smith, E. A.; Ward, D. T.; Schmitt, M. W.; Phenneger, M. C.; Vaughn, F. J.; Lupisella, M. L.

    1989-01-01

    Lifetime prediction techniques developed by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) are described. These techniques were developed to predict the Solar Maximum Mission (SMM) spacecraft orbit, which is decaying due to atmospheric drag, with reentry predicted to occur before the end of 1989. Lifetime predictions were also performed for the Long Duration Exposure Facility (LDEF), which was deployed on the 1984 SMM repair mission and is scheduled for retrieval on another Space Transportation System (STS) mission later this year. Concepts used in the lifetime predictions were tested on the San Marco spacecraft, which reentered the Earth's atmosphere on December 6, 1988. Ephemerides predicting the orbit evolution of the San Marco spacecraft until reentry were generated over the final 90 days of the mission when the altitude was less than 380 kilometers. The errors in the predicted ephemerides are due to errors in the prediction of atmospheric density variations over the lifetime of the satellite. To model the time dependence of the atmospheric densities, predictions of the solar flux at the 10.7-centimeter wavelength were used in conjunction with Harris-Priester (HP) atmospheric density tables. Orbital state vectors, together with the spacecraft mass and area, are used as input to the Goddard Trajectory Determination System (GTDS). Propagations proceed in monthly segments, with the nominal atmospheric drag model scaled for each month according to the predicted monthly average value of F10.7. Calibration propagations are performed over a period of known orbital decay to obtain the effective ballistic coefficient. Progagations using plus or minus 2 sigma solar flux predictions are also generated to estimate the despersion in expected reentry dates. Definitive orbits are compared with these predictions as time expases. As updated vectors are received, these are also propagated to reentryto continually update the lifetime predictions.

  19. Estimates of uncertainties in analysis of positron lifetime spectra for metals

    International Nuclear Information System (INIS)

    Eldrup, M.; Huang, Y.M.; McKee, B.T.A.

    1978-01-01

    The effects of uncertainties and errors in various constraints used in the analysis of multi-component life-time spectra of positrons annihilating in metals containing defects have been investigated in detail using computer simulated decay spectra and subsequent analysis. It is found that the errors in the fitted values of the main component lifetimes and intensities introduced from incorrect values of the instrumental resolution function and off the source-surface components can easily exceed the statistic uncertainties. The effect of an incorrect resolution function may be reduced by excluding the peak regions of the spectra from the analysis. The influence of using incorrect source-surface components in the analysis may on the other hand be reduced by including the peak regions of the spectra. A main conclusion of the work is that extreme caution should be exercised to avoid introducing large errors through the constraints used in the analysis of experimental lifetime data. (orig.) [de

  20. The Impact of Metallic Impurities on Minority Carrier Lifetime in High Purity N-type Silicon

    Science.gov (United States)

    Yoon, Yohan

    Boron-doped p-type silicon is the industry standard silicon solar cell substrate. However, it has serious limitations: iron boron (Fe-B) pairs and light induced degradation (LID). To suppress LID, the replacement of boron by gallium as a p-type dopant has been proposed. Although this eliminates B-O related defects, gallium-related pairing with iron, oxygen, and carbon can reduce lifetime in this material. In addition resistivity variations are more pronounced in gallium doped ingots, however Continuous-Czochralski (c-Cz) growth technologies are being developed to overcome this problem. In this work lifetime limiting factors and resistivity variations have been investigated in this material. The radial and axial variations of electrically active defects were observed using deep level transient spectroscopy (DLTS) these have been correlated to lifetime and resistivity variations. The DLTS measurements demonstrated that iron-related pairs are responsible for the lifetime variations. Specifically, Fe-Ga pairs were found to be important recombination sites and are more detrimental to lifetime than Fei. Typically n-type silicon has a higher minority carrier lifetime than p-type silicon with similar levels of contamination. That is because n-type silicon is more tolerant to metallic impurities, especially Fe. Also, it has no serious issues in relation to lifetime degradation, such as FeB pairs and light-induced degradation (LID). However, surface passivation of the p + region in p+n solar cells is much more problematic than the n+p case where silicon nitride provides very effective passivation of the cell. SiO2 is the most effective passivation for n type surfaces, but it does not work well on B-doped surfaces, resulting in inadequate performance. Al2O3 passivation layer suggested for B-doped emitters. With this surface passivation layer a 23.2 % conversion efficiency has been achieved. After this discovery n-type silicon is now being seriously considered for

  1. Distribution of Short-Term and Lifetime Predicted Risks of Cardiovascular Diseases in Peruvian Adults.

    Science.gov (United States)

    Quispe, Renato; Bazo-Alvarez, Juan Carlos; Burroughs Peña, Melissa S; Poterico, Julio A; Gilman, Robert H; Checkley, William; Bernabé-Ortiz, Antonio; Huffman, Mark D; Miranda, J Jaime

    2015-08-07

    Short-term risk assessment tools for prediction of cardiovascular disease events are widely recommended in clinical practice and are used largely for single time-point estimations; however, persons with low predicted short-term risk may have higher risks across longer time horizons. We estimated short-term and lifetime cardiovascular disease risk in a pooled population from 2 studies of Peruvian populations. Short-term risk was estimated using the atherosclerotic cardiovascular disease Pooled Cohort Risk Equations. Lifetime risk was evaluated using the algorithm derived from the Framingham Heart Study cohort. Using previously published thresholds, participants were classified into 3 categories: low short-term and low lifetime risk, low short-term and high lifetime risk, and high short-term predicted risk. We also compared the distribution of these risk profiles across educational level, wealth index, and place of residence. We included 2844 participants (50% men, mean age 55.9 years [SD 10.2 years]) in the analysis. Approximately 1 of every 3 participants (34% [95% CI 33 to 36]) had a high short-term estimated cardiovascular disease risk. Among those with a low short-term predicted risk, more than half (54% [95% CI 52 to 56]) had a high lifetime predicted risk. Short-term and lifetime predicted risks were higher for participants with lower versus higher wealth indexes and educational levels and for those living in urban versus rural areas (PPeruvian adults were classified as low short-term risk but high lifetime risk. Vulnerable adults, such as those from low socioeconomic status and those living in urban areas, may need greater attention regarding cardiovascular preventive strategies. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  2. Distribution of Short-Term and Lifetime Predicted Risks of Cardiovascular Diseases in Peruvian Adults

    Science.gov (United States)

    Quispe, Renato; Bazo-Alvarez, Juan Carlos; Burroughs Peña, Melissa S; Poterico, Julio A; Gilman, Robert H; Checkley, William; Bernabé-Ortiz, Antonio; Huffman, Mark D; Miranda, J Jaime

    2015-01-01

    Background Short-term risk assessment tools for prediction of cardiovascular disease events are widely recommended in clinical practice and are used largely for single time-point estimations; however, persons with low predicted short-term risk may have higher risks across longer time horizons. Methods and Results We estimated short-term and lifetime cardiovascular disease risk in a pooled population from 2 studies of Peruvian populations. Short-term risk was estimated using the atherosclerotic cardiovascular disease Pooled Cohort Risk Equations. Lifetime risk was evaluated using the algorithm derived from the Framingham Heart Study cohort. Using previously published thresholds, participants were classified into 3 categories: low short-term and low lifetime risk, low short-term and high lifetime risk, and high short-term predicted risk. We also compared the distribution of these risk profiles across educational level, wealth index, and place of residence. We included 2844 participants (50% men, mean age 55.9 years [SD 10.2 years]) in the analysis. Approximately 1 of every 3 participants (34% [95% CI 33 to 36]) had a high short-term estimated cardiovascular disease risk. Among those with a low short-term predicted risk, more than half (54% [95% CI 52 to 56]) had a high lifetime predicted risk. Short-term and lifetime predicted risks were higher for participants with lower versus higher wealth indexes and educational levels and for those living in urban versus rural areas (PPeruvian adults were classified as low short-term risk but high lifetime risk. Vulnerable adults, such as those from low socioeconomic status and those living in urban areas, may need greater attention regarding cardiovascular preventive strategies. PMID:26254303

  3. Model of lifetime prediction - Study of the behaviour of polymers and organic matrix composites

    International Nuclear Information System (INIS)

    Colin, X.

    2009-01-01

    The team 'Aging of Organic Materials' of the Process and Engineering Laboratory in Mechanics and Materials (Arts et Metiers, ParisTech) has developed the model of lifetime prediction for the prediction of the behaviour of polymers and organic composites. This model has already given evidence of a real predictive mean for various industrial applications, as for instance the prediction of a rupture under the coupled effect of a mechanical load and a chemical degradation. (O.M.)

  4. Predicting dietborne metal toxicity from metal influxes

    Science.gov (United States)

    Croteau, M.-N.; Luoma, S.N.

    2009-01-01

    Dietborne metal uptake prevails for many species in nature. However, the links between dietary metal exposure and toxicity are not well understood. Sources of uncertainty include the lack of suitable tracers to quantify exposure for metals such as copper, the difficulty to assess dietary processes such as food ingestion rate, and the complexity to link metal bioaccumulation and effects. We characterized dietborne copper, nickel, and cadmium influxes in a freshwater gastropod exposed to diatoms labeled with enriched stable metal isotopes. Metal influxes in Lymnaea stagnalis correlated linearly with dietborne metal concentrations over a range encompassing most environmental exposures. Dietary Cd and Ni uptake rate constants (kuf) were, respectively, 3.3 and 2.3 times higher than that for Cu. Detoxification rate constants (k detox) were similar among metals and appeared 100 times higher than efflux rate constants (ke). Extremely high Cu concentrations reduced feeding rates, causing the relationship between exposure and influx to deviate from linearity; i.e., Cu uptake rates leveled off between 1500 and 1800 nmol g-1 day-1. L. stagnalis rapidly takes up Cu, Cd, and Ni from food but detoxifies the accumulated metals, instead of reducing uptake or intensifying excretion. Above a threshold uptake rate, however, the detoxification capabilities of L. stagnalis are overwhelmed.

  5. Fluorescence lifetime microscopy for monitoring cell adhesion using metal induced energy transfer

    Science.gov (United States)

    Hwang, Wonsang; Seo, JinWon; Song, Jun ho; Kim, DongEun; Won, YoungJae; Choi, In-Hong; Yoo, Kyung-Hwa; Kim, Dug Young

    2018-02-01

    A precise control and a reliable monitoring tool for the adhesion properties of a cell are very important in atherosclerosis studies. If endothelial cells in contact with the intracellular membrane are not attached securely, low-density lipoprotein (LDL) particles can enter into the inner membrane. It is therefore necessary to measure conditions under which endothelial cell detachment occurs. When a cell is attached to a metal thin film, the lifetime of a fluorescence probe attached to the membrane of the cell is reduced by the metal-induced energy transfer (MIET). Fluorescence lifetime imaging microscopy (FLIM) is used to monitor the attachment condition of a cell to a metal surface using FRET. However, this requires high numerical aperture (NA) objective lens because axial confocal resolution must be smaller than the cell thickness. This requirement limits the field of view of the measurement specimen. In this study we provides a new method which can measure adhesion properties of endothelial cells even with a low NA objective lens by resolving two lifetime components in FLIM.

  6. Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

    KAUST Repository

    Jang, Ji-Wook

    2017-08-25

    Widespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with scalable techniques and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). Here, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one of the most promising metal oxide photoelectrodes, as a method to overcome the carrier transport limitations. Time-resolved microwave and terahertz conductivity measurements reveal more than twofold enhancement of the carrier lifetime for the hydrogen-treated BiVO4, without significantly affecting the carrier mobility. This is in contrast to the case of tungsten-doped BiVO4, although hydrogen is also a donor type dopant in BiVO4. The enhancement in carrier lifetime is found to be caused by significant reduction of trap-assisted recombination, either via passivation or reduction of deep trap states related to vanadium antisite on bismuth or vanadium interstitials according to density functional theory calculations. Overall, these findings provide further insights on the interplay between defect modulation and carrier transport in metal oxides, which benefit the development of low-cost, highly-efficient solar energy conversion devices.

  7. Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

    Science.gov (United States)

    Li, Zhigang; Liu, Boying; Yuan, Mengxiong; Zhang, Feifei; Guo, Jiaqiang

    2016-01-01

    Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

  8. Characterization of Initial Parameter Information for Lifetime Prediction of Electronic Devices.

    Directory of Open Access Journals (Sweden)

    Zhigang Li

    Full Text Available Newly manufactured electronic devices are subject to different levels of potential defects existing among the initial parameter information of the devices. In this study, a characterization of electromagnetic relays that were operated at their optimal performance with appropriate and steady parameter values was performed to estimate the levels of their potential defects and to develop a lifetime prediction model. First, the initial parameter information value and stability were quantified to measure the performance of the electronics. In particular, the values of the initial parameter information were estimated using the probability-weighted average method, whereas the stability of the parameter information was determined by using the difference between the extrema and end points of the fitting curves for the initial parameter information. Second, a lifetime prediction model for small-sized samples was proposed on the basis of both measures. Finally, a model for the relationship of the initial contact resistance and stability over the lifetime of the sampled electromagnetic relays was proposed and verified. A comparison of the actual and predicted lifetimes of the relays revealed a 15.4% relative error, indicating that the lifetime of electronic devices can be predicted based on their initial parameter information.

  9. An Overview of Different Approaches for Battery Lifetime Prediction

    Science.gov (United States)

    Zhang, Peng; Liang, Jun; Zhang, Feng

    2017-05-01

    With the rapid development of renewable energy and the continuous improvement of the power supply reliability, battery energy storage technology has been wildly used in power system. Battery degradation is a nonnegligible issue when battery energy storage system participates in system design and operation strategies optimization. The health assessment and remaining cycle life estimation of battery gradually become a challenge and research hotspot in many engineering areas. In this paper, the battery capacity falling and internal resistance increase are presented on the basis of chemical reactions inside the battery. The general life prediction models are analysed from several aspects. The characteristics of them as well as their application scenarios are discussed in the survey. In addition, a novel weighted Ah ageing model with the introduction of the Ragone curve is proposed to provide a detailed understanding of the ageing processes. A rigorous proof of the mathematical theory about the proposed model is given in the paper.

  10. Method to predict fatigue lifetimes of GRP wind turbine blades and comparison with experiments

    Energy Technology Data Exchange (ETDEWEB)

    Echtermeyer, A.T. [Det Norske Veritas Research AS, Hoevik (Norway); Kensche, C. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Stuttgart (Germany, F.R); Bach, P. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Poppen, M. [Aeronautical Research Inst. of Sweden, Bromma (Sweden); Lilholt, H.; Andersen, S.I.; Broendsted, P. [Risoe National Lab., Roskilde (Denmark)

    1996-12-01

    This paper describes a method to predict fatigue lifetimes of fiber reinforced plastics in wind turbine blades. It is based on extensive testing within the EU-Joule program. The method takes the measured fatigue properties of a material into account so that credit can be given to materials with improved fatigue properties. The large number of test results should also give confidence in the fatigue calculation method for fiber reinforced plastics. The method uses the Palmgren-Miner sum to predict lifetimes and is verified by tests using well defined load sequences. Even though this approach is generally well known in fatigue analysis, many details in the interpretation and extrapolation of the measurements need to be clearly defined, since they can influence the results considerably. The following subjects will be described: Method to measure SN curves and to obtain tolerance bounds, development of a constant lifetime diagram, evaluation of the load sequence, use of Palmgren-Miner sum, requirements for load sequence testing. The fatigue lifetime calculation method has been compared against measured data for simple loading sequences and the more complex WISPERX loading sequence for blade roots. The comparison is based on predicted mean lifetimes, using the same materials to obtain the basic SN curves and to measure laminates under complicated loading sequences. 24 refs, 7 figs, 5 tabs

  11. Activation analysis of dual-purpose metal cask after the end of design lifetime for decommission

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Man; Ku, Ji Young; Dho Ho Seog; Cho, Chun Hyung [Korea Radioactive Waste Agency, Daejeon (Korea, Republic of); Ko, Jae Hun [Korea Nuclear Engineering and Service Co., Daejeon (Korea, Republic of)

    2016-12-15

    The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5·ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, {sup 60}Co had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as {sup 28}Al and {sup 24}Na had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that

  12. Estimates of Uncertainties in Analysis of Positron Lifetime Spectra for Metals

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Huang, Y. M.; McKee, B. T. A.

    1978-01-01

    by excluding the peak regions of the spectra from the analysis. The influence of using incorrect source-surface components in the analysis may on the other hand be reduced by including the peak regions of the spectra. A main conclusion of the work is that extreme caution should be exercised to avoid......The effects of uncertainties and errors in various constraints used in the analysis of multi-component life-time spectra of positrons annihilating in metals containing defects have been investigated in detail using computer simulated decay spectra and subsequent analysis. It is found...... that the errors in the fitted values of the main components lifetimes and intensities introduced from incorrect values of the instrumental resolution function and of the source-surface components can easily exceed the statistical uncertainties. The effect of an incorrect resolution function may be reduced...

  13. Prediction of the lifetime productive and reproductive performance of Holstein cows managed for different lactation durations, using a model of lifetime nutrient partitioning

    DEFF Research Database (Denmark)

    Gaillard, Charlotte; Martin, O; Blavy, P

    2016-01-01

    The GARUNS model is a lifetime performance model taking into account the changing physiological priorities of an animal during its life and through repeated reproduction cycles. This dynamic and stochastic model has been previously used to predict the productive and reproductive performance...... of various genotypes of cows across feeding systems. In the present paper, we used this model to predict the lifetime productive and reproductive performance of Holstein cows for different lactation durations, with the aim of determining the lifetime scenario that optimizes cows' performance defined...... by lifetime efficiency (ratio of total milk energy yield to total energy intake) and pregnancy rate. To evaluate the model, data from a 16-mo extended lactation experiment on Holstein cows were used. Generally, the model could consistently fit body weight, milk yield, and milk components of these cows...

  14. Hydrogen and helium in metals: positron lifetime experiments. Quarterly report 3. quarter 1987

    International Nuclear Information System (INIS)

    Rajainmaeki, Hannu.

    1987-09-01

    This thesis reviews a new approach to studying the role of hydrogen and helium in defect recovery of metals by the positron lifetime technique. A cryostat has been built at the University of Jyvaeskylae for irradiating and/or implaning solids by high-energy proton or helium beams from the MC-20 cyclotron. The samples can be kept continuously below 20 K and the isochronal annealings and the subsequent positron lifetime measurements are carried ou in the same cryostat after the irradiations. During the implantations below 20 K both impuities (H or He) and Frenkel pairs are produced simultaneously. By measuring positron lifetimes during the annealing detailed information is obtained about radiation damage, impurity-defect interactions, lattice defect annealing, void nucleation and formation of helium bubbles. In this work positron lifetime spectroscopy has been utilized for the first time to study defect recovery below the liquid nitrogen temperature (77 K). The annealing stages are investigated in aluminium, nickel and molybdenum in the temperature range 20-700 K. Hydrogen is found to get trapped at vacancies in all the studied metals with binding energies 0.53+-0.04 and 1.6+-0.1 eV, respectively. Trapped hydrogen retards the vacancy migration in Al and Mo, while H-vancancy pairs dissociate in Ni below the free vacancy migration stage. helium gets deeply trapped at vacancies in Al and migrates substitutionally with the activation energy of 1.3+-0.1 eV. Helium-vacancy pairs are observed to nucleate into clusters and form helium bubbles which are stable up to the Al melting temperature. The growth mechanisms for the bubbles are established as thermal vacancy absorption and bubble migration/coalescence

  15. Effect of the final-state interaction on the initial core-hole lifetime: the case of the 4s-hole lifetime of Sn metal

    International Nuclear Information System (INIS)

    Ohno, Masahide

    2003-01-01

    The first theoretical study of the effect of the final-state interaction on the initial core-hole lifetime is presented. The 4s-hole lifetime width of Sn metal is calculated by an ab-initio atomic many-body theory (Green's function method). When the final-state interaction in the 4p4d two-hole state, created by the 4s -1 -4p -1 4d -1 εf super Coster-Kronig (CK) transition of the initial 4s hole, is explicitly taken into account, the ab-initio atomic many-body calculation of the 4s-hole X-ray photoelectron spectroscopy (XPS) spectrum of Sn atom can provide excellent agreement with experiment in both the 4s-hole energy and the 4s-hole lifetime width. Otherwise, the many-body calculation underestimates considerably the 4s-hole lifetime width. The 4p4d two-hole state interacts strongly with the 4d triple-hole state by the 4p -1 4d -1 -4d -3 εf super CK transition. The interaction affects greatly the initial 4s-hole lifetime width

  16. Retrospective lifetime dietary patterns predict cognitive performance in community-dwelling older Australians.

    Science.gov (United States)

    Hosking, Diane E; Nettelbeck, Ted; Wilson, Carlene; Danthiir, Vanessa

    2014-07-28

    Dietary intake is a modifiable exposure that may have an impact on cognitive outcomes in older age. The long-term aetiology of cognitive decline and dementia, however, suggests that the relevance of dietary intake extends across the lifetime. In the present study, we tested whether retrospective dietary patterns from the life periods of childhood, early adulthood, adulthood and middle age predicted cognitive performance in a cognitively healthy sample of 352 older Australian adults >65 years. Participants completed the Lifetime Diet Questionnaire and a battery of cognitive tests designed to comprehensively assess multiple cognitive domains. In separate regression models, lifetime dietary patterns were the predictors of cognitive factor scores representing ten constructs derived by confirmatory factor analysis of the cognitive test battery. All regression models were progressively adjusted for the potential confounders of current diet, age, sex, years of education, English as native language, smoking history, income level, apoE ɛ4 status, physical activity, other past dietary patterns and health-related variables. In the adjusted models, lifetime dietary patterns predicted cognitive performance in this sample of older adults. In models additionally adjusted for intake from the other life periods and mechanistic health-related variables, dietary patterns from the childhood period alone reached significance. Higher consumption of the 'coffee and high-sugar, high-fat extras' pattern predicted poorer performance on simple/choice reaction time, working memory, retrieval fluency, short-term memory and reasoning. The 'vegetable and non-processed' pattern negatively predicted simple/choice reaction time, and the 'traditional Australian' pattern positively predicted perceptual speed and retrieval fluency. Identifying early-life dietary antecedents of older-age cognitive performance contributes to formulating strategies for delaying or preventing cognitive decline.

  17. Preliminary lifetime predictions for 304 stainless steel as the LANL ABC blanket material

    International Nuclear Information System (INIS)

    Park, J.J.; Buksa, J.J.; Houts, M.G.; Arthur, E.D.

    1997-11-01

    The prediction of materials lifetime in the preconceptual Los Alamos National Laboratory (LANL) Accelerator-Based Conversion of Plutonium (ABC) is of utmost interest. Because Hastelloy N showed good corrosion resistance to the Oak Ridge National Laboratory Molten Salt Reactor Experiment fuel salt that is similar to the LANL ABC fuel salt, Hastelloy N was originally proposed for the LANL ABC blanket material. In this paper, the possibility of using 304 stainless steel as a replacement for the Hastelloy N is investigated in terms of corrosion issues and fluence-limit considerations. An attempt is made, based on the previous Fast Flux Test Facility design data, to predict the preliminary lifetime estimate of the 304 stainless steel used in the blanket region of the LANL ABC

  18. Lifetimes of Multiply Alkylated Cyclopentane Oil in Contact with Various Metals, Evaluated with Vacuum Spiral Orbit Tribometer

    Science.gov (United States)

    Pepper, Stephen V.

    2018-01-01

    The dependence of the lifetimes of small quantities of a Multiply Alkylated Cyclopentane (MAC) lubricant oil, Pennzane (Registered Trademark) 2001A (Nye Lubricants, Inc.), in rolling and sliding contact with different metals was evaluated with a vacuum spiral orbit tribometer. The metals were the bearing alloys 52100 steel, 440C steel, 17-4 PH steel and Nitinol 60 and the elements chromium, vanadium and titanium. The lifetimes of the lubricant oil on different metals fell into distinct groups with 52100 greater than 440C approx. Nitinol 60 greater than 17-4 PH for the order of the lifetimes of the steels and chromium greater than vanadium greater than titanium for the order of the lifetimes for the elements. The limited life of the small quantities of oil is assumed to be due to its consumption by the tribochemical reaction of the oil with the different metal bearing materials. The lifetimes are then inversely related to the reaction rates of the oil molecules with the various metals: the longest life of 52100 steel having the lowest reaction rate and the shortest life of titanium having the highest reaction rate. Mechanisms for the tribochemical reactions are discussed.

  19. Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites

    Science.gov (United States)

    Afful, Andoh; Opperman, Ben; Steyn, Herman

    2016-07-01

    Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.

  20. A new lifetime estimation model for a quicker LED reliability prediction

    Science.gov (United States)

    Hamon, B. H.; Mendizabal, L.; Feuillet, G.; Gasse, A.; Bataillou, B.

    2014-09-01

    LED reliability and lifetime prediction is a key point for Solid State Lighting adoption. For this purpose, one hundred and fifty LEDs have been aged for a reliability analysis. LEDs have been grouped following nine current-temperature stress conditions. Stress driving current was fixed between 350mA and 1A and ambient temperature between 85C and 120°C. Using integrating sphere and I(V) measurements, a cross study of the evolution of electrical and optical characteristics has been done. Results show two main failure mechanisms regarding lumen maintenance. The first one is the typically observed lumen depreciation and the second one is a much more quicker depreciation related to an increase of the leakage and non radiative currents. Models of the typical lumen depreciation and leakage resistance depreciation have been made using electrical and optical measurements during the aging tests. The combination of those models allows a new method toward a quicker LED lifetime prediction. These two models have been used for lifetime predictions for LEDs.

  1. Lifetime prediction for organic coating under alternating hydrostatic pressure by artificial neural network

    Science.gov (United States)

    Tian, Wenliang; Meng, Fandi; Liu, Li; Li, Ying; Wang, Fuhui

    2017-01-01

    A concept for prediction of organic coatings, based on the alternating hydrostatic pressure (AHP) accelerated tests, has been presented. An AHP accelerated test with different pressure values has been employed to evaluate coating degradation. And a back-propagation artificial neural network (BP-ANN) has been established to predict the service property and the service lifetime of coatings. The pressure value (P), immersion time (t) and service property (impedance modulus |Z|) are utilized as the parameters of the network. The average accuracies of the predicted service property and immersion time by the established network are 98.6% and 84.8%, respectively. The combination of accelerated test and prediction method by BP-ANN is promising to evaluate and predict coating property used in deep sea. PMID:28094340

  2. Reliability of steam-turbine rotors. Task 1. Lifetime prediction analysis system. Final report

    International Nuclear Information System (INIS)

    Nair, P.K.; Pennick, H.G.; Peters, J.E.; Wells, C.H.

    1982-12-01

    Task 1 of RP 502, Reliability of Steam Turbine Rotors, resulted in the development of a computerized lifetime prediction analysis system (STRAP) for the automatic evaluation of rotor integrity based upon the results of a boresonic examination of near-bore defects. Concurrently an advanced boresonic examination system (TREES), designed to acquire data automatically for lifetime analysis, was developed and delivered to the maintenance shop of a major utility. This system and a semi-automated, state-of-the-art system (BUCS) were evaluated on two retired rotors as part of the Task 2 effort. A modified nonproprietary version of STRAP, called SAFER, is now available for rotor lifetime prediction analysis. STRAP and SAFER share a common fracture analysis postprocessor for rapid evaluation of either conventional boresonic amplitude data or TREES cell data. The final version of this postprocessor contains general stress intensity correlations for elliptical cracks in a radial stress gradient and provision for elastic-plastic instability of the ligament between an imbedded crack and the bore surface. Both linear elastic and ligament rupture models were developed for rapid analysis of linkup within three-dimensional clusters of defects. Bore stress-rupture criteria are included, but a creep-fatigue crack growth data base is not available. Physical and mechanical properties of air-melt 1CrMoV forgings are built into the program; however, only bounding values of fracture toughness versus temperature are available. Owing to the lack of data regarding the probability of flaw detection for the boresonic systems and of quantitative verification of the flaw linkup analysis, automatic evlauation of boresonic results is not recommended, and the lifetime prediction system is currently restricted to conservative, deterministic analysis of specified flaw geometries

  3. Advances in fatigue lifetime predictive techniques; Proceedings of the Symposium, San Francisco, CA, Apr. 24, 1990

    International Nuclear Information System (INIS)

    Mitchell, M.R.; Landgraf, R.W.

    1992-01-01

    Recent progress in the development of methods to predict fatigue performance of materials and structures is reviewed. Attention is given to general approaches to fatigue mechanics, elevated temperature phenomena, spectrum loading, the multiaxial behavior, and applications. Particular attention is given to a fracture-mechanics-based model for cumulative damage assessment, thermo-mechanical fatigue life prediction methods, a probabilistic fracture mechanics approach for structural reliability assessment of space flight systems, a multiaxial fatigue life estimation technique, plasticity and fatigue damage modeling of severely loaded tubing, damage evaluation in composite materials using thermographic stress analysis, and fatigue lifetime monitoring in power plants

  4. Predicting Shear Transformation Events in Metallic Glasses

    Science.gov (United States)

    Xu, Bin; Falk, Michael L.; Li, J. F.; Kong, L. T.

    2018-03-01

    Shear transformation is the elementary process for plastic deformation of metallic glasses, the prediction of the occurrence of the shear transformation events is therefore of vital importance to understand the mechanical behavior of metallic glasses. In this Letter, from the view of the potential energy landscape, we find that the protocol-dependent behavior of shear transformation is governed by the stress gradient along its minimum energy path and we propose a framework as well as an atomistic approach to predict the triggering strains, locations, and structural transformations of the shear transformation events under different shear protocols in metallic glasses. Verification with a model Cu64 Zr36 metallic glass reveals that the prediction agrees well with athermal quasistatic shear simulations. The proposed framework is believed to provide an important tool for developing a quantitative understanding of the deformation processes that control mechanical behavior of metallic glasses.

  5. Positron annihilation lifetime spectroscopy (PALS) application in metal barrier layer integrity for porous low- k materials

    CERN Document Server

    Simon, Lin; Gidley, D W; Wetzel, J T; Monnig, K A; Ryan, E T; Simon, Jang; Douglas, Yu; Liang, M S; En, W G; Jones, E C; Sturm, J C; Chan, M J; Tiwari, S C; Hirose, M

    2002-01-01

    Positron Annihilation Lifetime Spectroscopy (PALS) is a useful tool to pre-screen metal barrier integrity for Si-based porous low-k dielectrics. Pore size of low-k, thickness of metal barrier Ta, positronium (Ps) leakage from PALS, trench sidewall morphology, electrical test from one level metal (1LM) pattern wafer and Cu diffusion analysis were all correlated. Macro-porous low-k (pore size >=200 AA) and large scale meso-porous low-k (>50~200 AA) encounter both Ps leakage and Cu diffusion into low-k dielectric in the 0.25 mu mL/0.3 mu mS structures when using SEMATECH in-house PVD Ta 250 AA as barrier layer. For small scale meso-porous (>20~50 AA) and micro- porous (<=20 AA) low-k, no Ps leakage and no Cu diffusion into low-k were observed even with PVD Ta 50 AA, which is proved also owing to sidewall densification to seal all sidewall pores due to plasma etch and ash. For future technology, smaller pore size of porous Si-based low-k (=<50 AA) will be preferential for dense low-k like trench sidewall to...

  6. Prediction of the lifetime of nitrile-butadiene rubber by FT-IR.

    Science.gov (United States)

    Kawashima, Tetsuya; Ogawa, Toshio

    2005-12-01

    A quantitative measurement method with FT-IR was proposed for a thermal degradation analysis of nitrile-butadiene rubber (NBR). An NBR film was prepared as a model sample on a barium fluoride (BaF2) crystal plate, which was subjected to a heat treatment. The absorbances of various functional groups were measured directly by FT-IR after thermal degradation at high temperatures. By measuring the absorbances, it was possible to readily determine quantitatively each of the functional groups after the degradation of NBR. By assuming that the NBR lifetime was the point at which the absorbance of a carbon-carbon double bond reaches 45% of that prior to thermal treatment, a method for predicting the lifetime of NBR heated below 150 degrees C was proposed, by using an Arrhenius plot of the heating time versus heating temperature.

  7. Lifetime Measurements of $ \\pi ^+ \\pi ^- $ and $\\pi^{+-} K^{-+}$ Atoms to Test Low-Energy QCD Predictions

    CERN Multimedia

    Iliescu, M A; Ponta, T C; Dumitriu, D E; Afanasyev, L; Zhabitskiy, M; Rykalin, V; Hons, Z; Schacher, J; Yazkov, V; Gerndt, J; Detraz, C C; Guaraldo, C; Dreossi, D; Smolik, J; Gorchakov, O; Nikitin, M; Dudarev, A; Kluson, J; Hansroul, M; Okada, K; Constantinescu, S; Kruglov, V; Komarov, V; Takeutchi, F; Tarta, P D; Kuptsov, A; Nemenov, L; Karpukhin, V; Shliapnikov, P; Brekhovskikh, V; Saborido silva, J J; Drijard, D; Rappazzo, G F; Pentia, M C; Gugiu, M M; Kruglova, L; Pustylnik, Z; Trojek, T; Duma, M; Ciocarlan, C; Kulikov, A; Ol'shevskiy, V; Ryazantsev, A; Chiba, M; Anania, A; Tarasov, A; Gritsay, K; Lapchine, V; Cechak, T; Vrba, T; Lopez aguera, A

    2002-01-01

    %PS212 \\\\ \\\\ The proposed experiment aims to measure the lifetime of $ \\pi ^+ \\pi ^- $ atoms in the ground state with 10\\% precision, using the 24~GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10$ ^- ^{1} ^{5} $s is dictated by a strong interaction at low energy, the precise measurement of this quantity enables to determine a combination of S-wave pion scattering lengths to 5\\%. Pion scattering lengths have been calculated in the framework of chiral perturbation theory and values predicted at the same level of accuracy have, up to now, never been confronted with accurate experimental data. Such a measurement would submit the understanding of chiral symmetry breaking of QCD to a crucial test.

  8. An application of characteristic function in order to predict reliability and lifetime of aeronautical hardware

    Energy Technology Data Exchange (ETDEWEB)

    Żurek, Józef; Kaleta, Ryszard; Zieja, Mariusz [Air Force Institute of Technology ul. Księcia Bolesława 6 01-494 Warsaw (Poland)

    2016-06-08

    The forecasting of reliability and life of aeronautical hardware requires recognition of many and various destructive processes that deteriorate the health/maintenance status thereof. The aging of technical components of aircraft as an armament system proves of outstanding significance to reliability and safety of the whole system. The aging process is usually induced by many and various factors, just to mention mechanical, biological, climatic, or chemical ones. The aging is an irreversible process and considerably affects (i.e. reduces) reliability and lifetime of aeronautical equipment. Application of the characteristic function of the aging process is suggested to predict reliability and lifetime of aeronautical hardware. An increment in values of diagnostic parameters is introduced to formulate then, using the characteristic function and after some rearrangements, the partial differential equation. An analytical dependence for the characteristic function of the aging process is a solution to this equation. With the inverse transformation applied, the density function of the aging of aeronautical hardware is found. Having found the density function, one can determine the aeronautical equipment’s reliability and lifetime. The in-service collected or the life tests delivered data are used to attain this goal. Coefficients in this relationship are found using the likelihood function.

  9. An application of characteristic function in order to predict reliability and lifetime of aeronautical hardware

    International Nuclear Information System (INIS)

    Żurek, Józef; Kaleta, Ryszard; Zieja, Mariusz

    2016-01-01

    The forecasting of reliability and life of aeronautical hardware requires recognition of many and various destructive processes that deteriorate the health/maintenance status thereof. The aging of technical components of aircraft as an armament system proves of outstanding significance to reliability and safety of the whole system. The aging process is usually induced by many and various factors, just to mention mechanical, biological, climatic, or chemical ones. The aging is an irreversible process and considerably affects (i.e. reduces) reliability and lifetime of aeronautical equipment. Application of the characteristic function of the aging process is suggested to predict reliability and lifetime of aeronautical hardware. An increment in values of diagnostic parameters is introduced to formulate then, using the characteristic function and after some rearrangements, the partial differential equation. An analytical dependence for the characteristic function of the aging process is a solution to this equation. With the inverse transformation applied, the density function of the aging of aeronautical hardware is found. Having found the density function, one can determine the aeronautical equipment’s reliability and lifetime. The in-service collected or the life tests delivered data are used to attain this goal. Coefficients in this relationship are found using the likelihood function.

  10. Behavioral lifetime of human auditory sensory memory predicted by physiological measures.

    Science.gov (United States)

    Lu, Z L; Williamson, S J; Kaufman, L

    1992-12-04

    Noninvasive magnetoencephalography makes it possible to identify the cortical area in the human brain whose activity reflects the decay of passive sensory storage of information about auditory stimuli (echoic memory). The lifetime for decay of the neuronal activation trace in primary auditory cortex was found to predict the psychophysically determined duration of memory for the loudness of a tone. Although memory for the loudness of a specific tone is lost, the remembered loudness decays toward the global mean of all of the loudnesses to which a subject is exposed in a series of trials.

  11. Predicting the life-time benefit of school-based smoking prevention programmes.

    Science.gov (United States)

    Jit, Mark; Aveyard, Paul; Barton, Pelham; Meads, Catherine A

    2010-06-01

    School-based smoking prevention programmes may delay the age of smoking initiation, but do not appear to achieve lasting reductions in smoking prevalence beyond school-leaving age. We explored whether delaying the age at which someone initiates smoking may have life-time benefits by increasing the likelihood of quitting in later life. Data from the General Household Survey of Great Britain were used in a logistic regression model to examine the association between age at which someone initiates regular smoking and the probability that the person will quit smoking later in life. The effect of confounding variables (sex, ethnicity, socio-economic class, education and geographical location) was taken into account. The predicted relationship was used in a cohort model to estimate the life-time reduction in smoking prevalence and all-cause mortality of a school-based smoking prevention programme. Age of regular smoking initiation was associated strongly with the probability of quitting later in life (coefficient -0.103, P < 0.001). The strength of the association was slightly reduced but still significant when confounding variables were included (coefficient -0.075, P < 0.001). An intervention that delays smoking initiation without decreasing smoking prevalence at age 18 may reduce adult smoking prevalence by 0.13-0.32% (depending on age) and all-cause mortality by 0.09% over the life-time of the sample. School-based smoking prevention programmes have potential for a beneficial effect over the life-time of the participants even if they have no apparent effect at school-leaving age.

  12. Studies on Mathematical Models of Wet Adhesion and Lifetime Prediction of Organic Coating/Steel by Grey System Theory.

    Science.gov (United States)

    Meng, Fandi; Liu, Ying; Liu, Li; Li, Ying; Wang, Fuhui

    2017-06-28

    A rapid degradation of wet adhesion is the key factor controlling coating lifetime, for the organic coatings under marine hydrostatic pressure. The mathematical models of wet adhesion have been studied by Grey System Theory (GST). Grey models (GM) (1, 1) of epoxy varnish (EV) coating/steel and epoxy glass flake (EGF) coating/steel have been established, and a lifetime prediction formula has been proposed on the basis of these models. The precision assessments indicate that the established models are accurate, and the prediction formula is capable of making precise lifetime forecasting of the coatings.

  13. Consequences of metallic fuel-cladding liquid phase attack during over-temperature transient on fuel element lifetime

    International Nuclear Information System (INIS)

    Lahm, C.E.; Koenig, J.F.; Seidel, B.R.

    1990-01-01

    Metallic fuel elements irradiated in EBR-II at temperatures significantly higher than design, causing liquid phase attack of the cladding, were subsequently irradiated at normal operating temperatures to first breach. The fuel element lifetime was compared to that for elements not subjected to the over-temperature transient and found to be equivalent. 1 ref., 3 figs

  14. Impact of lifetime model selections on the reliability prediction of IGBT modules in modular multilevel converters

    DEFF Research Database (Denmark)

    Zhang, Yi; Wang, Huai; Wang, Zhongxu

    2017-01-01

    , this paper benchmarks the most commonly-employed lifetime models of power semiconductor devices for offshore Modular Multilevel Converters (MMC) based wind farms. The benchmarking reveals that the lifetime model selection has a significant impact on the lifetime estimation. The use of analytical lifetime...

  15. Validation of Lifetime Prediction of IGBT Modules Based on Linear Damage Accumulation by Means of Superimposed Power Cycling Tests

    DEFF Research Database (Denmark)

    Choi, Ui-Min; Ma, Ke; Blaabjerg, Frede

    2018-01-01

    In this paper, the lifetime prediction of power device modules based on the linear damage accumulation is studied in conjunction with simple mission profiles of converters. Superimposed power cycling conditions, which are called simple mission profiles in this paper, are made based on a lifetime ...... prediction of IGBT modules under power converter applications.......In this paper, the lifetime prediction of power device modules based on the linear damage accumulation is studied in conjunction with simple mission profiles of converters. Superimposed power cycling conditions, which are called simple mission profiles in this paper, are made based on a lifetime...... model in respect to junction temperature swing duration. This model has been built based on 39 power cycling test results of 600-V 30-A three-phase-molded IGBT modules. Six tests are performed under three superimposed power cycling conditions using an advanced power cycling test setup. The experimental...

  16. Prediction and reconstruction of future and missing unobservable modified Weibull lifetime based on generalized order statistics

    Directory of Open Access Journals (Sweden)

    Amany E. Aly

    2016-04-01

    Full Text Available When a system consisting of independent components of the same type, some appropriate actions may be done as soon as a portion of them have failed. It is, therefore, important to be able to predict later failure times from earlier ones. One of the well-known failure distributions commonly used to model component life, is the modified Weibull distribution (MWD. In this paper, two pivotal quantities are proposed to construct prediction intervals for future unobservable lifetimes based on generalized order statistics (gos from MWD. Moreover, a pivotal quantity is developed to reconstruct missing observations at the beginning of experiment. Furthermore, Monte Carlo simulation studies are conducted and numerical computations are carried out to investigate the efficiency of presented results. Finally, two illustrative examples for real data sets are analyzed.

  17. A Well-Designed Parameter Estimation Method for Lifetime Prediction of Deteriorating Systems with Both Smooth Degradation and Abrupt Damage

    Directory of Open Access Journals (Sweden)

    Chuanqiang Yu

    2015-01-01

    Full Text Available Deteriorating systems, which are subject to both continuous smooth degradation and additional abrupt damages due to a shock process, can be often encountered in engineering. Modeling the degradation evolution and predicting the lifetime of this kind of systems are both interesting and challenging in practice. In this paper, we model the degradation trajectory of the deteriorating system by a random coefficient regression (RCR model with positive jumps, where the RCR part is used to model the continuous smooth degradation of the system and the jump part is used to characterize the abrupt damages due to random shocks. Based on a specified threshold level, the probability density function (PDF and cumulative distribution function (CDF of the lifetime can be derived analytically. The unknown parameters associated with the derived lifetime distributions can be estimated via a well-designed parameter estimation procedure on the basis of the available degradation recordings of the deteriorating systems. An illustrative example is finally provided to demonstrate the implementation and superiority of the newly proposed lifetime prediction method. The experimental results reveal that our proposed lifetime prediction method with the dedicated parameter estimation strategy can get more accurate lifetime predictions than the rival model in literature.

  18. Residual lifetime prediction for lithium-ion battery based on functional principal component analysis and Bayesian approach

    International Nuclear Information System (INIS)

    Cheng, Yujie; Lu, Chen; Li, Tieying; Tao, Laifa

    2015-01-01

    Existing methods for predicting lithium-ion (Li-ion) battery residual lifetime mostly depend on a priori knowledge on aging mechanism, the use of chemical or physical formulation and analytical battery models. This dependence is usually difficult to determine in practice, which restricts the application of these methods. In this study, we propose a new prediction method for Li-ion battery residual lifetime evaluation based on FPCA (functional principal component analysis) and Bayesian approach. The proposed method utilizes FPCA to construct a nonparametric degradation model for Li-ion battery, based on which the residual lifetime and the corresponding confidence interval can be evaluated. Furthermore, an empirical Bayes approach is utilized to achieve real-time updating of the degradation model and concurrently determine residual lifetime distribution. Based on Bayesian updating, a more accurate prediction result and a more precise confidence interval are obtained. Experiments are implemented based on data provided by the NASA Ames Prognostics Center of Excellence. Results confirm that the proposed prediction method performs well in real-time battery residual lifetime prediction. - Highlights: • Capacity is considered functional and FPCA is utilized to extract more information. • No features required which avoids drawbacks induced by feature extraction. • A good combination of both population and individual information. • Avoiding complex aging mechanism and accurate analytical models of batteries. • Easily applicable to different batteries for life prediction and RLD calculation.

  19. Can the lifetime of the superheater tubes be predicted according to the fuel analyses? Assessment from field and laboratory data

    Energy Technology Data Exchange (ETDEWEB)

    Salmenoja, K. [Kvaerner Pulping Oy, Tampere (Finland)

    1998-12-31

    Lifetime of the superheaters in different power boilers is more or less still a mystery. This is especially true in firing biomass based fuels (biofuels), such as bark, forest residues, and straw. Due to the unhomogeneous nature of the biofuels, the lifetime of the superheaters may vary from case to case. Sometimes the lifetime is significantly shorter than originally expected, sometimes no corrosion even in the hottest tubes is observed. This is one of the main reasons why the boiler operators often demand for a better predictability on the corrosion resistance of the materials to avoid unscheduled shutdowns. (orig.) 9 refs.

  20. Can the lifetime of the superheater tubes be predicted according to the fuel analyses? Assessment from field and laboratory data

    Energy Technology Data Exchange (ETDEWEB)

    Salmenoja, K [Kvaerner Pulping Oy, Tampere (Finland)

    1999-12-31

    Lifetime of the superheaters in different power boilers is more or less still a mystery. This is especially true in firing biomass based fuels (biofuels), such as bark, forest residues, and straw. Due to the unhomogeneous nature of the biofuels, the lifetime of the superheaters may vary from case to case. Sometimes the lifetime is significantly shorter than originally expected, sometimes no corrosion even in the hottest tubes is observed. This is one of the main reasons why the boiler operators often demand for a better predictability on the corrosion resistance of the materials to avoid unscheduled shutdowns. (orig.) 9 refs.

  1. Predicting formation enthalpies of metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Andreasen, A.

    2004-12-01

    In order for the hydrogen based society viz. a society in which hydrogen is the primary energy carrier to become realizable an efficient way of storing hydrogen is required. For this purpose metal hydrides are serious candidates. Metal hydrides are formed by chemical reaction between hydrogen and metal and for the stable hydrides this is associated with release of heat ({delta}H{sub f} ). The more thermodynamically stable the hydride, the larger {delta}H{sub f}, and the higher temperature is needed in order to desorp hydrogen (reverse reaction) and vice versa. For practical application the temperature needed for desorption should not be too high i.e. {delta}H{sub f} should not be too large. If hydrogen desorption is to be possible below 100 deg C (which is the ultimate goal if hydrogen storage in metal hydrides should be used in conjunction with a PEM fuel cell), {delta}H{sub f} should not exceed -48 kJ/mol. Until recently only intermetallic metal hydrides with a storage capacity less than 2 wt.% H{sub 2} have met this criterion. However, discovering reversible hydrogen storage in complex metal hydrides such as NaAlH{sub 4} (5.5 wt. % reversible hydrogen capacity) have revealed a new group of potential candiates. However, still many combination of elements from the periodic table are yet to be explored. Since experimental determination of thermodynamic properties of the vast combinations of elements is tedious it may be advantagous to have a predictive tool for this task. In this report different ways of predicting {delta}H{sub f} for binary and ternary metal hydrides are reviewed. Main focus will be on how well these methods perform numerically i.e. how well experimental results are resembled by the model. The theoretical background of the different methods is only briefly reviewed. (au)

  2. Personalized prediction of lifetime benefits with statin therapy for asymptomatic individuals: a modeling study.

    Directory of Open Access Journals (Sweden)

    Bart S Ferket

    Full Text Available BACKGROUND: Physicians need to inform asymptomatic individuals about personalized outcomes of statin therapy for primary prevention of cardiovascular disease (CVD. However, current prediction models focus on short-term outcomes and ignore the competing risk of death due to other causes. We aimed to predict the potential lifetime benefits with statin therapy, taking into account competing risks. METHODS AND FINDINGS: A microsimulation model based on 5-y follow-up data from the Rotterdam Study, a population-based cohort of individuals aged 55 y and older living in the Ommoord district of Rotterdam, the Netherlands, was used to estimate lifetime outcomes with and without statin therapy. The model was validated in-sample using 10-y follow-up data. We used baseline variables and model output to construct (1 a web-based calculator for gains in total and CVD-free life expectancy and (2 color charts for comparing these gains to the Systematic Coronary Risk Evaluation (SCORE charts. In 2,428 participants (mean age 67.7 y, 35.5% men, statin therapy increased total life expectancy by 0.3 y (SD 0.2 and CVD-free life expectancy by 0.7 y (SD 0.4. Age, sex, smoking, blood pressure, hypertension, lipids, diabetes, glucose, body mass index, waist-to-hip ratio, and creatinine were included in the calculator. Gains in total and CVD-free life expectancy increased with blood pressure, unfavorable lipid levels, and body mass index after multivariable adjustment. Gains decreased considerably with advancing age, while SCORE 10-y CVD mortality risk increased with age. Twenty-five percent of participants with a low SCORE risk achieved equal or larger gains in CVD-free life expectancy than the median gain in participants with a high SCORE risk. CONCLUSIONS: We developed tools to predict personalized increases in total and CVD-free life expectancy with statin therapy. The predicted gains we found are small. If the underlying model is validated in an independent cohort, the

  3. A model for predicting the lifetimes of Grade-2 titanium nuclear waste containers

    Energy Technology Data Exchange (ETDEWEB)

    Shoesmith, D W; Ikeda, B M; Bailey, M G; Quinn, M J; LeNeveu, D M [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

    1995-08-01

    The development of a model to predict the lifetimes of Grade-2 titanium containers for nuclear fuel waste is described. This model assumes that the corrosion processes most likely to lead to container failure are crevice corrosion, hydrogen-induced cracking and general corrosion. Because of the expected evolution of waste vault conditions from initially warm (<{approx} 100 deg C) and oxidizing to eventually cool (<30 deg C) and non-oxiding, the period for which crevice corrosion can propagate will be limited by repassivation, and long container lifetimes will be achieved since the rate of general corrosion is extremely low. However, in the model presented, not only is it assumed that crevices will initiate rapidly on all containers, but also that the propagation of these crevices will continue indefinitely since conditions will remain sufficiently oxiding for repassivation to be avoided. The mathematical development of the model is described in detail. A simple ramped distribution is used to describe the failures due to the presence of initial defects. For crevice corrosion the propagation rates are assumed to be normally distributed and to be determined predominantly by temperature. The temperature dependence of the crevice propagation rate is determined from the calculated cooling profiles for the containers and an experimentally determined Arrhenius relationship for crevice propagation rates. The cooling profiles are approximated by double or single step functions, depending on the location of the container within the vault. The experimental data upon which this model is based is extensively reviewed. This review includes descriptions of the available data to describe and quantify the processes of general corrosion, crevice corrosion and hydrogen-induced cracking. For crevice corrosion and hydrogen-induced cracking the results of studies on both Grades-2 and -12 are presented. Also, the effects of impurities in the Grade-2 material are discussed.

  4. A model for predicting the lifetimes of Grade-2 titanium nuclear waste containers

    International Nuclear Information System (INIS)

    Shoesmith, D.W.; Ikeda, B.M.; Bailey, M.G.; Quinn, M.J.; LeNeveu, D.M.

    1995-08-01

    The development of a model to predict the lifetimes of Grade-2 titanium containers for nuclear fuel waste is described. This model assumes that the corrosion processes most likely to lead to container failure are crevice corrosion, hydrogen-induced cracking and general corrosion. Because of the expected evolution of waste vault conditions from initially warm (<∼ 100 deg C) and oxidizing to eventually cool (<30 deg C) and non-oxiding, the period for which crevice corrosion can propagate will be limited by repassivation, and long container lifetimes will be achieved since the rate of general corrosion is extremely low. However, in the model presented, not only is it assumed that crevices will initiate rapidly on all containers, but also that the propagation of these crevices will continue indefinitely since conditions will remain sufficiently oxiding for repassivation to be avoided. The mathematical development of the model is described in detail. A simple ramped distribution is used to describe the failures due to the presence of initial defects. For crevice corrosion the propagation rates are assumed to be normally distributed and to be determined predominantly by temperature. The temperature dependence of the crevice propagation rate is determined from the calculated cooling profiles for the containers and an experimentally determined Arrhenius relationship for crevice propagation rates. The cooling profiles are approximated by double or single step functions, depending on the location of the container within the vault. The experimental data upon which this model is based is extensively reviewed. This review includes descriptions of the available data to describe and quantify the processes of general corrosion, crevice corrosion and hydrogen-induced cracking. For crevice corrosion and hydrogen-induced cracking the results of studies on both Grades-2 and -12 are presented. Also, the effects of impurities in the Grade-2 material are discussed. Special attention is

  5. Chairside CAD/CAM materials. Part 3: Cyclic fatigue parameters and lifetime predictions.

    Science.gov (United States)

    Wendler, Michael; Belli, Renan; Valladares, Diana; Petschelt, Anselm; Lohbauer, Ulrich

    2018-06-01

    Chemical and mechanical degradation play a key role on the lifetime of dental restorative materials. Therefore, prediction of their long-term performance in the oral environment should base on fatigue, rather than inert strength data, as commonly observed in the dental material's field. The objective of the present study was to provide mechanistic fatigue parameters of current dental CAD/CAM materials under cyclic biaxial flexure and assess their suitability in predicting clinical fracture behaviors. Eight CAD/CAM materials, including polycrystalline zirconia (IPS e.max ZirCAD), reinforced glasses (Vitablocs Mark II, IPS Empress CAD), glass-ceramics (IPS e.max CAD, Suprinity PC, Celtra Duo), as well as hybrid materials (Enamic, Lava Ultimate) were evaluated. Rectangular plates (12×12×1.2mm 3 ) with highly polished surfaces were prepared and tested in biaxial cyclic fatigue in water until fracture using the Ball-on-Three-Balls (B3B) test. Cyclic fatigue parameters n and A* were obtained from the lifetime data for each material and further used to build SPT diagrams. The latter were used to compare in-vitro with in-vivo fracture distributions for IPS e.max CAD and IPS Empress CAD. Susceptibility to subcritical crack growth under cyclic loading was observed for all materials, being more severe (n≤20) in lithium-based glass-ceramics and Vitablocs Mark II. Strength degradations of 40% up to 60% were predicted after only 1 year of service. Threshold stress intensity factors (K th ) representing the onset of subcritical crack growth (SCG), were estimated to lie in the range of 0.37-0.44 of K Ic for the lithium-based glass-ceramics and Vitablocs Mark II and between 0.51-0.59 of K Ic for the other materials. Failure distributions associated with mechanistic estimations of strength degradation in-vitro showed to be useful in interpreting failure behavior in-vivo. The parameter K th stood out as a better predictor of clinical performance in detriment to the SCG n

  6. Lifetime experience with (classic) psychedelics predicts pro-environmental behavior through an increase in nature relatedness.

    Science.gov (United States)

    Forstmann, Matthias; Sagioglou, Christina

    2017-08-01

    In a large-scale ( N = 1487) general population online study, we investigated the relationship between past experience with classic psychedelic substances (e.g. LSD, psilocybin, mescaline), nature relatedness, and ecological behavior (e.g. saving water, recycling). Using structural equation modeling we found that experience with classic psychedelics uniquely predicted self-reported engagement in pro-environmental behaviors, and that this relationship was statistically explained by people's degree of self-identification with nature. Our model controlled for experiences with other classes of psychoactive substances (cannabis, dissociatives, empathogens, popular legal drugs) as well as common personality traits that usually predict drug consumption and/or nature relatedness (openness to experience, conscientiousness, conservatism). Although correlational in nature, results suggest that lifetime experience with psychedelics in particular may indeed contribute to people's pro-environmental behavior by changing their self-construal in terms of an incorporation of the natural world, regardless of core personality traits or general propensity to consume mind-altering substances. Thereby, the present research adds to the contemporary literature on the beneficial effects of psychedelic substance use on mental wellbeing, hinting at a novel area for future research investigating their potentially positive effects on a societal level. Limitations of the present research and future directions are discussed.

  7. The Impact of Mission Profile Models on the Predicted Lifetime of IGBT Modules in the Modular Multilevel Converter

    DEFF Research Database (Denmark)

    Zhang, Yi; Wang, Huai; Wang, Zhongxu

    2017-01-01

    and electrical power modeling methods on the estimated lifetime of IGBT modules in an MMC for offshore wind power application. In a 30 MW MMC case study, an annual wind speed profile with a resolution of 1 s/data, 10 minute/data, and 1 hour/data are considered, respectively. A method to re-generate higher......The reliability aspect study of Modular Multilevel Converter (MMC) is of great interest in industry applications, such as offshore wind. Lifetime prediction of key components is an important tool to design MMC with fulfilled reliability specifications. While many efforts have been made...... to the lifetime prediction of IGBT modules in renewable energy applications by considering long-term varying operation conditions (i.e., mission profile), the justifications of using the associated mission profiles are still missed. This paper investigates the impact of mission profile data resolutions...

  8. European Network of Excellence on NPP residual lifetime prediction methodologies (NULIFE)

    International Nuclear Information System (INIS)

    Badea, M.; Vidican, D.

    2006-01-01

    Within Europe massive investments in nuclear power have been made to meet present and future energy needs. The majority of nuclear reactors have been operating for longer than 20 years and their continuing safe operation depends crucially on effective lifetime management. Furthermore, to extend the economic return on investment and environmental benefits, it is necessary to ensure in advance the safe operation of nuclear reactors for 60 years, a period which is typically 20 years in excess of nominal design life. This depends on a clear understanding of, and predictive capability for, how safety margins may be maintained as components degrade under operational conditions. Ageing mechanisms, environment effects and complex loadings increase the likelihood of damage to safety relevant systems, structures and components. The ability to claim increased benefits from reduced conservatism via improved assessments is therefore of great value. Harmonisation and qualification are essential for industrial exploitation of approaches developed for life prediction methodology. Several European organisations and networks have been at the forefront of the development of advanced methodologies in this area. However, these efforts have largely been made at national level and their overall impact and benefit (in comparison to the situation in the USA) has been reduced by fragmentation. There is a need to restructure the networking approach in order to create a single organisational entity capable of working at European level to produce and exploit R and D in support of the safe and competitive operation of nuclear power plants. It is also critical to ensure the competitiveness of European plant life management (PLIM) services at international level, in particular with the USA and Asian countries. To the above challenges the European Network on European research in residual lifetime prediction methodologies (NULIFE) will: - Create a Europe-wide body in order to achieve scientific and

  9. Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

    NARCIS (Netherlands)

    Yazdan Mehr, M.; van Driel, W.D.; Zhang, G.Q.

    2015-01-01

    A methodology, based on accelerated degradation testing, is developed to predict the lifetime of remote phosphor plates used in solid-state lighting (SSL) applications. Both thermal stress and light intensity are used to accelerate degradation reaction in remote phosphor plates. A reliability model,

  10. Differentiating corporal punishment from physical abuse in the prediction of lifetime aggression.

    Science.gov (United States)

    King, Alan R; Ratzak, Abrianna; Ballantyne, Sage; Knutson, Shane; Russell, Tiffany D; Pogalz, Colton R; Breen, Cody M

    2018-05-01

    Corporal punishment and parental physical abuse often co-occur during upbringing, making it difficult to differentiate their selective impacts on psychological functioning. Associations between corporal punishment and a number of lifetime aggression indicators were examined in this study after efforts to control the potential influence of various forms of co-occurring maltreatment (parental physical abuse, childhood sexual abuse, sibling abuse, peer bullying, and observed parental violence). College students (N = 1,136) provided retrospective self-reports regarding their history of aggression and levels of exposure to childhood corporal punishment and maltreatment experiences. Analyses focused on three hypotheses: 1) The odds of experiencing childhood physical abuse would be higher among respondents reporting frequent corporal punishment during upbringing; 2) Corporal punishment scores would predict the criterion aggression indices after control of variance associated with childhood maltreatment; 3) Aggression scores would be higher among respondents classified in the moderate and elevated corporal punishment risk groups. Strong support was found for the first hypothesis since the odds of childhood physical abuse recollections were higher (OR = 65.3) among respondents who experienced frequent (>60 total disciplinary acts) corporal punishment during upbringing. Partial support was found for the second and third hypotheses. Dimensional and categorical corporal punishment scores were associated significantly with half of the criterion measures. These findings support efforts to dissuade reliance on corporal punishment to manage child behavior. © 2018 Wiley Periodicals, Inc.

  11. Durability study and lifetime prediction of baseline proton exchange membrane fuel cell under severe operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Marrony, M.; Quenet, S.; Aslanides, A. [European Institute for Energy Research, Emmy-Noether Strasse 11, 76131 Karlsruhe (Germany); Barrera, R.; Ginocchio, S.; Montelatici, L. [Edison, Via Giorgio La Pira 2, 10028 Trofarello (Italy)

    2008-08-01

    Comparative studies of mechanical and electrochemical properties of Nafion{sup registered} - and sulfonated polyetheretherketone polymer-type membranes are carried out under severe fuel cell conditions required by industrials, within stationary and cycling electric load profiles. These membranes are proposed to be used in PEM between 70 and 90 C as fluorinated or non-fluorinated baseline membranes, respectively. Thus, though the performance of both membranes remains suitable, Nafion{sup registered} backbone brought better mechanical properties and higher electrochemical stabilities than sulfonated polyetheretherketone backbone. The performance stability and the mechanical strength of the membrane-electrode assembly were shown to be influenced by several intrinsic properties of the membrane (e.g., thermal pre-treatment, thickness) and external conditions (fuel cell operating temperature, relative humidity). Finally, a lifetime prediction for membranes under stationary conditions is proposed depending on the operation temperature. At equivalent thicknesses (i.e. 50 {mu}m), Nafion{sup registered} membranes were estimated able to operate into the 80-90 C range while sulfonated polyetheretherketone would be limited into the 70-80 C range. This approach brings baseline information about the capability of these types of polymer electrolyte membrane under fuel cell critical operations. Finally, it is revealed as a potential tool for the selection of the most promising advanced polymers for the ensuing research phase. (author)

  12. Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

    KAUST Repository

    Jang, Ji-Wook; Friedrich, Dennis; Mü ller, Sö nke; Lamers, Marlene; Hempel, Hannes; Lardhi, Sheikha F.; Cao, Zhen; Harb, Moussab; Cavallo, Luigi; Heller, René ; Eichberger, Rainer; van de Krol, Roel; Abdi, Fatwa F.

    2017-01-01

    and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). Here, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one

  13. Development of a lifetime prediction model for lithium-ion batteries based on extended accelerated aging test data

    Science.gov (United States)

    Ecker, Madeleine; Gerschler, Jochen B.; Vogel, Jan; Käbitz, Stefan; Hust, Friedrich; Dechent, Philipp; Sauer, Dirk Uwe

    2012-10-01

    Battery lifetime prognosis is a key requirement for successful market introduction of electric and hybrid vehicles. This work aims at the development of a lifetime prediction approach based on an aging model for lithium-ion batteries. A multivariable analysis of a detailed series of accelerated lifetime experiments representing typical operating conditions in hybrid electric vehicle is presented. The impact of temperature and state of charge on impedance rise and capacity loss is quantified. The investigations are based on a high-power NMC/graphite lithium-ion battery with good cycle lifetime. The resulting mathematical functions are physically motivated by the occurring aging effects and are used for the parameterization of a semi-empirical aging model. An impedance-based electric-thermal model is coupled to the aging model to simulate the dynamic interaction between aging of the battery and the thermal as well as electric behavior. Based on these models different drive cycles and management strategies can be analyzed with regard to their impact on lifetime. It is an important tool for vehicle designers and for the implementation of business models. A key contribution of the paper is the parameterization of the aging model by experimental data, while aging simulation in the literature usually lacks a robust empirical foundation.

  14. Biological and socio-cultural factors during the school years predicting women’s lifetime educational attainment

    Science.gov (United States)

    Hendrick, C. Emily; Cohen, Alison K.; Deardorff, Julianna

    2015-01-01

    BACKGROUND Lifetime educational attainment is an important predictor of health and well-being for women in the United States. In the current study, we examine the roles of socio-cultural factors in youth and an understudied biological life event, pubertal timing, in predicting women’s lifetime educational attainment. METHODS Using data from the National Longitudinal Survey of Youth 1997 cohort (N = 3889), we conducted sequential multivariate linear regression analyses to investigate the influences of macro-level and family-level socio-cultural contextual factors in youth (region of country, urbanicity, race/ethnicity, year of birth, household composition, mother’s education, mother’s age at first birth) and early menarche, a marker of early pubertal development, on women’s educational attainment after age 24. RESULTS Pubertal timing and all socio-cultural factors in youth, other than year of birth, predicted women’s lifetime educational attainment in bivariate models. Family factors had the strongest associations. When family factors were added to multivariate models, geographic region in youth and pubertal timing were no longer significant. CONCLUSION Our findings provide additional evidence that family factors should be considered when developing comprehensive and inclusive interventions in childhood and adolescence to promote lifetime educational attainment among girls. PMID:26830508

  15. Oxidation limited lifetime of Ni-Base metal foams in the temperature range 700-900 C

    Energy Technology Data Exchange (ETDEWEB)

    Chyrkin, Anton; Singheiser, Lorenz; Quadakkers, Willem Joseph [Forschungszentrum Juelich GmbH, IEF-2, Juelich (Germany); Schulze, Sebastian Leif; Bleck, Wolfgang [Department of Ferrous Metallurgy, RWTH Aachen University, Aachen (Germany); Piron-Abellan, Javier [Vallourec Mannesmann Tubes, Duesseldorf (Germany)

    2010-09-15

    INCONEL 625 metal foams produced from alloy powder by the slip-reaction-foam-sinter-process are tested in respect to cyclic oxidation behavior in air in the temperature range 700-900 C. The structure of the oxide scales formed on the foam particles is characterized using optical microscopy and SEM/EDX analysis. Main emphasis is put on studying the oxidation limited lifetimes of the foams as function of temperature and foam microstructure. It is shown that mechanical disintegration during long term oxidation at the highest test temperatures is caused by a critical depletion of the Cr content in the alloy as a result of the growth of the initially formed surface chromia layer. This results in chemical breakaway due to accelerated oxide growth of voluminous Ni-rich oxide on chromium exhausted alloy particles. Lifetime modeling based on calculation of Cr-depletion in the alloy at the oxide/metal interface of each individual foam particle using the DICTRA software is in good agreement with the experimentally determined values of the time to breakaway. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Damage Prediction in Sheet Metal Forming

    International Nuclear Information System (INIS)

    Saanouni, Khemais; Badreddine, Houssem

    2007-01-01

    to kill the fully damaged elements in order to describe the macroscopic crack propagation. Various 2D and 3D examples are given in order to show the capability of the methodology to predict the damage initiation and growth during various sheet metal forming processes

  17. Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET

    International Nuclear Information System (INIS)

    Lei Xiao-Yi; Liu Hong-Xia; Zhang Kai; Zhang Yue; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

    2013-01-01

    The hot carrier effect (HCE) of an ultra-deep sub-micron p-channel metal—oxide semiconductor field-effect transistor (pMOSFET) is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time (t), channel width (W), channel length (L), and stress voltage (V d ) is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  18. Summary report for IAEA CRP on lifetime prediction for the first wall of a fusion machine (JAERI contribution)

    International Nuclear Information System (INIS)

    Suzuki, Satoshi; Araki, Masanori; Akiba, Masato

    1993-03-01

    IAEA Coordinated Research Program (CRP) on 'Lifetime Prediction for the First Wall of a Fusion Machine' was started in 1989. Five participants, Joint Research Centre (JRC-Ispra), The NET team, Kernforschungszentrum Karlsruhe (KfK), Russian Research Center and Japan Atomic Energy Research Institute, contributed in this activity. The purpose of the CRP is to evaluate the thermal fatigue behavior of the first wall of a next generation fusion machine by means of numerical methods and also to contribute the design activities for ITER (International Thermonuclear Experimental Reactor). Thermal fatigue experiments of a first wall mock-up which were carried out in JRC-Ispra were selected as a first benchmark exercise model. All participants performed finite element analyses with various analytical codes to predict the lifetime of the simulated first wall. The first benchmark exercise has successfully been finished in 1992. This report summarizes a JAERI's contribution for this first benchmark exercise. (author)

  19. Lifetime studies of high power rhodium/tungsten and molybdenum electrodes for application to AMTEC (alkali metal thermal-to-electric converter)

    Science.gov (United States)

    Williams, R. M.; Jeffries-Nakamura, B.; Underwood, M. L.; O'Connor, D.; Ryan, M. A.; Kikkert, S.; Bankston, C. P.

    1990-01-01

    A detailed and fundamental model for the electrochemical behavior of AMTEC electrodes is developed which can aid in interpreting the processes which occur during prolonged operation of these electrodes. Because the sintering and grain growth of metal particles is also a well-understood phenomenon, the changes in electrode performance which accompany its morphological evolution may be anticipated and modeled. The grain growth rate observed for porous Mo AMTEC electrodes is significantly higher than that predicted from surface diffusion data obtained at higher temperatures and incorporated into the grain growth model. The grain growth observed under AMTEC conditions is also somewhat higher than that measured for Mo films on BASE (beta-alumina solid electrolyte) substrates in vacuum or at similar temperatures. Results of modeling indicate that thin Mo electrodes may show significant performance degradation for extended operation (greater than 10,000 h) at higher operating temperatures (greater than 1150 K), whereas W/Rh and W/Pt electrodes are expected to show adequate performance at 1200 K for lifetimes greater than 10,000 h. It is pointed out that current collection grids and leads must consist of refractory metals such as Mo and W which do not accelerate sintering or metal migration.

  20. Predictive Modelling of Heavy Metals in Urban Lakes

    OpenAIRE

    Lindström, Martin

    2000-01-01

    Heavy metals are well-known environmental pollutants. In this thesis predictive models for heavy metals in urban lakes are discussed and new models presented. The base of predictive modelling is empirical data from field investigations of many ecosystems covering a wide range of ecosystem characteristics. Predictive models focus on the variabilities among lakes and processes controlling the major metal fluxes. Sediment and water data for this study were collected from ten small lakes in the ...

  1. Stable Early Maternal Report of Behavioral Inhibition Predicts Lifetime Social Anxiety Disorder in Adolescence

    Science.gov (United States)

    Chronis-Tuscano, Andrea; Degnan, Kathryn Amey; Pine, Daniel S.; Perez-Edgar, Koraly; Henderson, Heather A.; Diaz, Yamalis; Raggi, Veronica L.; Fox, Nathan A.

    2009-01-01

    The odds of a lifetime diagnosis of social anxiety disorder increased by 3.79 times for children who had a stable report of behavioral inhibition from their mothers. This finding has important implications for the early identification and prevention of social anxiety disorder.

  2. Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, M.

    2013-01-01

    The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

  3. Role of ultrathin metal fluoride layer in organic photovoltaic cells: mechanism of efficiency and lifetime enhancement.

    Science.gov (United States)

    Lim, Kyung-Geun; Choi, Mi-Ri; Kim, Ji-Hoon; Kim, Dong Hun; Jung, Gwan Ho; Park, Yongsup; Lee, Jong-Lam; Lee, Tae-Woo

    2014-04-01

    Although rapid progress has been made recently in bulk heterojunction organic solar cells, systematic studies on an ultrathin interfacial layer at the electron extraction contact have not been conducted in detail, which is important to improve both the device efficiency and the lifetime. We find that an ultrathin BaF2 layer at the electron extraction contact strongly influences the open-circuit voltage (Voc ) as the nanomorphology evolves with increasing BaF2 thickness. A vacuum-deposited ultrathin BaF2 layer grows by island growth, so BaF2 layers with a nominal thickness less than that of single-coverage layer (≈3 nm) partially cover the polymeric photoactive layer. As the nominal thickness of the BaF2 layer increased to that of a single-coverage layer, the Voc and power conversion efficiency (PCE) of the organic photovoltaic cells (OPVs) increased but the short-circuit current remained almost constant. The fill factor and the PCE decreased abruptly as the thickness of the BaF2 layer exceeded that of a single-coverage layer, which was ascribed to the insulating nature of BaF2 . We find the major cause of the increased Voc observed in these devices is the lowered work function of the cathode caused by the reaction and release of Ba from thin BaF2 films upon deposition of Al. The OPV device with the BaF2 layer showed a slightly improved maximum PCE (4.0 %) and a greatly (approximately nine times) increased device half-life under continuous simulated solar irradiation at 100 mW cm(-2) as compared with the OPV without an interfacial layer (PCE=2.1 %). We found that the photodegradation of the photoactive layer was not a major cause of the OPV degradation. The hugely improved lifetime with cathode interface modification suggests a significant role of the cathode interfacial layer that can help to prolong device lifetimes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Prediction of metal sorption in soils

    International Nuclear Information System (INIS)

    Westrich, Henry R.; Anderson, Harold L. Jr.; Arthur, Sara E.; Brady, Patrick V.; Cygan, Randall T.; Liang, Jianjie; Zhang, Pengchu; Yee, N.

    2000-01-01

    Radionuclide transport in soils and groundwaters is routinely calculated in performance assessment (PA) codes using simplified conceptual models for radionuclide sorption, such as the K D approach for linear and reversible sorption. Model inaccuracies are typically addressed by adding layers of conservativeness (e.g., very low K D 's), and often result in failed transport predictions or substantial increases in site cleanup costs. Realistic assessments of radionuclide transport over a wide range of environmental conditions can proceed only from accurate, mechanistic models of the sorption process. They have focused on the sorption mechanisms and partition coefficients for Cs + , Sr 2+ and Ba 2+ (analogue for Ra 2+ ) onto iron oxides and clay minerals using an integrated approach that includes computer simulations, sorption/desorption measurements, and synchrotron analyses of metal sorbed substrates under geochemically realistic conditions. Sorption of Ba 2+ and Sr 2+ onto smectite is strong, pH-independent, and fully reversible, suggesting that cation exchange at the interlayer basal sites controls the sorption process. Sr 2+ sorbs weakly onto geothite and quartz, and is pH-dependent. Sr 2+ sorption onto a mixture of smectite and goethite, however, is pH- and concentration dependent. The adsorption capacity of montmorillonite is higher than that of goethite, which may be attributed to the high specific surface area and reaction site density of clays. The presence of goethite also appears to control the extent of metal desorption. In-situ, extended X-ray absorption fine structure (EXAFS) spectroscopic measurements for montmorillonite and goethite show that the first shell of adsorbed Ba 2+ is coordinated by 6 oxygens. The second adsorption shell, however, varies with the mineral surface coverage of adsorbed Ba 2+ and the mineral substrate. This suggests that Ba 2+ adsorption on mineral surfaces involves more than one mechanism and that the stability of sorbed

  5. Thermal Characterization and Lifetime Prediction of LED Boards for SSL Lamp

    Directory of Open Access Journals (Sweden)

    J. Formanek

    2013-04-01

    Full Text Available This work presents a detailed 3-D thermo-mechanical modelling of two LED board technologies to compare their performance. LED board are considered to be used in high power 800 lumen retrofit SSL (Solid State Lighting lamp. Thermal, mechanical and life time properties are evaluated by numerical modelling. Experimental results measured on fabricated LED board samples are compared to calculated data. Main role of LED board in SSL lamp is to transport heat from LED die to a heat sink and keep the thermal stresses in all layers as low as possible. The work focuses on improving of new LED board thermal management. Moreover, reliability and lifetime of LED board has been inspected by numerical calculation and validated by experiment. Thermally induced stress has been studied for wide temperature range that can affect the LED boards (-40 to +125°C. Numerical modelling of thermal performance, thermal stress distribution and lifetime has been carried out with ANSYS structural analysis where temperature dependent stress-strain material properties have been taken into account. The objective of this study is to improve not only the thermal performance of new LED board, but also identification of potential problems from mechanical fatigue point of view. Accelerated lifetime testing (e.g., mechanical is carried out in order to study the failure behaviour of current and newly developed LED board.

  6. Neutron fluence determination for operation effectiveness assessment and prediction of WWER pressure vessel lifetime at the Kozloduy NPP

    Energy Technology Data Exchange (ETDEWEB)

    Apostolov, T; Ilieva, K; Belousov, S; Petrova, T; Antonov, S; Ivanov, K; Prodanova, R; Penev, I; Taskaev, E [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika; Ivanov, I; Tsokov, P; Nelov, N; Lilkov, B; Tsocheva, V; Monev, M; Velichkov, V; Kharalampieva, Ts [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

    1996-12-31

    Embrittlement processes in reactor pressure vessel (RPV) metal have been investigated by neutron dosimetry. A software package for fluence calculations has been developed and used for evaluation of the accumulated neutron fluence, the critical temperature of radiation embrittlement and the RPV lifetime. A digital reactivity meter DR-8 has been introduced for continuous neutron fluence monitoring. Estimates of the neutron fluence and the radiation state of all 6 units of the Kozloduy NPP are presented. The Unit 4 RPV is in the best state regarding metal embrittlement, while the Units 2 and 3 can be safely operated up to the end of their design lifetime only using dummy cassettes. The neutron fluence accumulation in the Unit 1 RPV is quite big and can not be reduced with annealing. Activity measurements of the Unit 1 internal wall shavings are made after the 14-th cycle which show a good agreement with calculated values (1.10{sup 5} Bq/g). The critical embrittlement temperature of the Units 1 - 4 is estimated as a function of the working cycles. 11 figs., 1 tab.

  7. Quasiparticle energies and lifetimes in a metallic chain model of a tunnel junction.

    Science.gov (United States)

    Szepieniec, Mark; Yeriskin, Irene; Greer, J C

    2013-04-14

    As electronics devices scale to sub-10 nm lengths, the distinction between "device" and "electrodes" becomes blurred. Here, we study a simple model of a molecular tunnel junction, consisting of an atomic gold chain partitioned into left and right electrodes, and a central "molecule." Using a complex absorbing potential, we are able to reproduce the single-particle energy levels of the device region including a description of the effects of the semi-infinite electrodes. We then use the method of configuration interaction to explore the effect of correlations on the system's quasiparticle peaks. We find that when excitations on the leads are excluded, the device's highest occupied molecular orbital and lowest unoccupied molecular orbital quasiparticle states when including correlation are bracketed by their respective values in the Hartree-Fock (Koopmans) and ΔSCF approximations. In contrast, when excitations on the leads are included, the bracketing property no longer holds, and both the positions and the lifetimes of the quasiparticle levels change considerably, indicating that the combined effect of coupling and correlation is to alter the quasiparticle spectrum significantly relative to an isolated molecule.

  8. Predicting, categorizing and intercomparing the lifetime of OPVs for different ageing tests

    DEFF Research Database (Denmark)

    Corazza, Michael; Krebs, Frederik C; Gevorgyan, Suren

    2014-01-01

    the acceleration factors between the moderate and harsh ISOS test conditions employed in the study, as well as identifying the level of improvement of the device stability after encapsulation. The effects of different device architectures and encapsulation techniques on ageing rates of the samples were also...... associated with the common time units was used for presenting the ageing data, which regardless of the spread in the lifetimes allowed categorizing the level of the stability of P3HT:PCBM based devices tested under different ageing conditions. Moreover, the approach also allowed for estimating...

  9. Converter-level FEM simulation for lifetime prediction of an LED driver with improved thermal modelling

    DEFF Research Database (Denmark)

    Niu, H.; Wang, H.; Ye, X.

    2017-01-01

    application. A converter-level finite element simulation (FEM) simulation is carried out to obtain the ambient temperature of electrolytic capacitors and power MOSFETs used in the LED driver, which takes into account the impact of the driver enclosure and the thermal coupling among different components....... Therefore, the proposed method bridges the link between the global ambient temperature profile outside of the enclosure and the local ambient temperature profiles of the components of interest inside the driver. A quantitative comparison of the estimated annual lifetime consumptions of MOSFETs...

  10. Lifetime prediction and reliability estimation methodology for Stirling-type pulse tube refrigerators by gaseous contamination accelerated degradation testing

    Science.gov (United States)

    Wan, Fubin; Tan, Yuanyuan; Jiang, Zhenhua; Chen, Xun; Wu, Yinong; Zhao, Peng

    2017-12-01

    Lifetime and reliability are the two performance parameters of premium importance for modern space Stirling-type pulse tube refrigerators (SPTRs), which are required to operate in excess of 10 years. Demonstration of these parameters provides a significant challenge. This paper proposes a lifetime prediction and reliability estimation method that utilizes accelerated degradation testing (ADT) for SPTRs related to gaseous contamination failure. The method was experimentally validated via three groups of gaseous contamination ADT. First, the performance degradation model based on mechanism of contamination failure and material outgassing characteristics of SPTRs was established. Next, a preliminary test was performed to determine whether the mechanism of contamination failure of the SPTRs during ADT is consistent with normal life testing. Subsequently, the experimental program of ADT was designed for SPTRs. Then, three groups of gaseous contamination ADT were performed at elevated ambient temperatures of 40 °C, 50 °C, and 60 °C, respectively and the estimated lifetimes of the SPTRs under normal condition were obtained through acceleration model (Arrhenius model). The results show good fitting of the degradation model with the experimental data. Finally, we obtained the reliability estimation of SPTRs through using the Weibull distribution. The proposed novel methodology enables us to take less than one year time to estimate the reliability of the SPTRs designed for more than 10 years.

  11. Prediction of free-volume-type correlations in glassy chalcogenides from positron annihilation lifetime measurements

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Ingram, A.; Shpotyuk, M.; Filipecki, J.

    2014-01-01

    Highlights: • Decisive role of specific chemical environment in free-volume correlations in glass. • Realistic free volumes in As–S/Se glass are defined by newly modified τ 2 -R formula. • Overestimated void sizes in chalcogenide glass as compared with molecular polymers. - Abstract: A newly modified correlation equation between defect-related positron lifetime determined within two-state trapping model and radius of corresponding free-volume-type defects was proposed to describe compositional variations in atomic-deficient structure of covalent-bonded chalcogenides like binary As–S/Se glasses. Specific chemical environment of free-volume voids around neighboring network-forming polyhedrons was shown to play a decisive role in this correlation, leading to systematically enhanced volumes in comparison with typical molecular substrates, such as polymers

  12. Prediction of free-volume-type correlations in glassy chalcogenides from positron annihilation lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O., E-mail: shpotyuk@novas.lviv.ua [Institute of Materials of SRC “Carat”, 212 Stryjska Str., Lviv 79031 (Ukraine); Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestcochowa 42200 (Poland); Ingram, A. [Opole University of Technology, 75 Ozimska Str., Opole 45370 (Poland); Shpotyuk, M. [Institute of Materials of SRC “Carat”, 212 Stryjska Str., Lviv 79031 (Ukraine); Lviv Polytechnic National University, 12 Bandery Str., Lviv 79013 (Ukraine); Filipecki, J. [Institute of Physics of Jan Dlugosz University, 13/15 al. Armii Krajowej, Czestcochowa 42200 (Poland)

    2014-11-01

    Highlights: • Decisive role of specific chemical environment in free-volume correlations in glass. • Realistic free volumes in As–S/Se glass are defined by newly modified τ{sub 2}-R formula. • Overestimated void sizes in chalcogenide glass as compared with molecular polymers. - Abstract: A newly modified correlation equation between defect-related positron lifetime determined within two-state trapping model and radius of corresponding free-volume-type defects was proposed to describe compositional variations in atomic-deficient structure of covalent-bonded chalcogenides like binary As–S/Se glasses. Specific chemical environment of free-volume voids around neighboring network-forming polyhedrons was shown to play a decisive role in this correlation, leading to systematically enhanced volumes in comparison with typical molecular substrates, such as polymers.

  13. Using downside CAPM theory to improve customer lifetime value prediction in non-contractual setting

    Directory of Open Access Journals (Sweden)

    Amir Albadvi

    2013-12-01

    Full Text Available Identifying and selecting the most profitable customers from a shareholder’s perspective is of great interest to marketing managers. One promising line in this regard is to explore the customer lifetime value and its profitable management over time. There is a significant body of marketing literature about CLV evaluation in terms of various perspectives. However, much less attention has been paid to the risk associated with customer relationships. Previous researches in this area considered risk as “variability of cash flows generated by customers”, regardless of the trend of variability. Whereas the upside and downside variability from the customer’s expected profitability are extremely different in CRM context. This paper provides a quantitative model based on downside Capital Asset Pricing Model (D-CAPM to evaluate risk-adjusted CLV and compares the results by employment of traditional CAPM. This paper contributes to this field by extending the discussion on customer risk measurement and provides an approach that enables marketing managers to evaluate the risk of decline from average profitability for different customer segments.

  14. Kinetic investigation and lifetime prediction of Cs-NIPAM-MBA-based thermo-responsive hydrogels.

    Science.gov (United States)

    Othman, Muhammad Bisyrul Hafi; Khan, Abbas; Ahmad, Zulkifli; Zakaria, Muhammad Razlan; Ullah, Faheem; Akil, Hazizan Md

    2016-01-20

    This study attempted to clarify the influence of a cross-linker, N,N-methylenebisacrylamide (MBA), and N-isopropylacrylamide (NIPAM) on the non-isothermal kinetic degradation, solid state and lifetime of hydrogels using the Flynn-Wall-Ozawa (F-W-O), Kissinger, and Coats-Redfern (C-Red) methods. The series of dual-responsive Cs-PNIPAM-MBA microgels were synthesized by soapless-emulsion free radical copolymerization in an aqueous medium at 70 °C. The thermal properties were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) under nitrogen atmosphere. The apparent activation energy using the chosen Flynn-Wall-Ozawa and Kissinger methods showed that they fitted each other. Meanwhile, the type of solid state mechanism was determined using the Coats-Redfern method proposed for F1 (pure Cs) and F2 (Cs-PNIPAM-MBA hydrogel series) types, which comprise random nucleation with one nucleus reacting on individual particles, and random nucleation with two nuclei reacting on individual particles, respectively. On average, a higher Ea was attributed to the greater cross-linking density of the Cs hydrogel. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Predicting formation enthalpies of metal hydrides

    DEFF Research Database (Denmark)

    Andreasen, A.

    2004-01-01

    of elements from the periodic table are yet to beexplored. Since experimental determination of thermodynamic properties of the vast combinations of elements is tedious it may be advantagous to have a predictive tool for this task. In this report different ways of predicting #DELTA#H_f for binary andternary...

  16. Personalized Prediction of Lifetime Benefits with Statin Therapy for Asymptomatic Individuals: A Modeling Study

    NARCIS (Netherlands)

    B.S. Ferket (Bart); B.J.H. van Kempen (Bob); J. Heeringa (Jan); S. Spronk (Sandra); K.E. Fleischmann (Kirsten); R.L. Nijhuis (Rogier); A. Hofman (Albert); E.W. Steyerberg (Ewout); M.G.M. Hunink (Myriam)

    2012-01-01

    textabstractBackground: Physicians need to inform asymptomatic individuals about personalized outcomes of statin therapy for primary prevention of cardiovascular disease (CVD). However, current prediction models focus on short-term outcomes and ignore the competing risk of death due to other causes.

  17. Thermo-mechanical behavior of power electronic packaging assemblies: From characterization to predictive simulation of lifetimes

    Science.gov (United States)

    Dalverny, O.; Alexis, J.

    2018-02-01

    This article deals with thermo-mechanical behavior of power electronic modules used in several transportation applications as railway, aeronautic or automotive systems. Due to a multi-layered structures, involving different materials with a large variation of coefficient of thermal expansion, temperature variations originated from active or passive cycling (respectively from die dissipation or environmental constraint) induces strain and stresses field variations, giving fatigue phenomenon of the system. The analysis of the behavior of these systems and their dimensioning require the implementation of complex modeling strategies by both the multi-physical and the multi-scale character of the power modules. In this paper we present some solutions for studying the thermomechanical behavior of brazed assemblies as well as taking into account the interfaces represented by the numerous metallizations involved in the process assembly.

  18. Developments in Property Predictions for Weld Metal

    National Research Council Canada - National Science Library

    Olson, D

    2003-01-01

    With the introduction of higher strength low-carbon steels, which have properties that are based on strengthening mechanisms other than the austenitic decomposition, new predictive expressions are required...

  19. Contribution to life-time predictions of gas turbine components under cyclic load

    Energy Technology Data Exchange (ETDEWEB)

    Hoelscher, R.

    1982-02-15

    The low cycle fatique life of gas turbine components is analysed using the turbine blade of the ATAR 101 F jet engine turbine as example. The results show that, among other things thermal stresses during start-up and shut-off cause considerable damage to the material. Tests using a model rig showed that damage caused by material creep and LCF-mechanisms stongly depended on cyclic parameters such as temperature, temperature development, and power etc. Two long-term tests confirm that the Manson model can be used to give a reasonable prediction of turbine blade life.

  20. Lifetime prediction of structures submitted to thermal fatigue loadings; Prediction de duree de vie de structures sous chargement de fatigue thermique

    Energy Technology Data Exchange (ETDEWEB)

    Amiable, S

    2006-01-15

    The aim of this work is to predict the lifetime of structures submitted to thermal fatigue loadings. This work lies within the studies undertaken by the CEA on the thermal fatigue problems from the french reactor of Civaux. In particular we study the SPLASH test: a specimen is heated continuously and cyclically cooled down by a water spray. This loading generates important temperature gradients in space and time and leads to the initiation and the propagation of a crack network. We propose a new thermo-mechanical model to simulate the SPLASH experiment and we propose a new fatigue criterion to predict the lifetime of the SPLASH specimen. We propose and compare several numerical models with various complexity to estimate the mechanical response of the SPLASH specimen. The practical implications of this work are the reevaluation of the hypothesis used in the French code RCC, which are used to simulate thermal shock and to interpret the results in terms of fatigue. This work leads to new perspectives on the mechanical interpretation of the fatigue criterion. (author)

  1. Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, M; Anderson, D P [Spectro Incorporated, Littleton, Massachusetts (United States)

    1998-12-31

    Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

  2. Machine and lubricant condition monitoring for extended equipment lifetimes and predictive maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, M.; Anderson, D.P. [Spectro Incorporated, Littleton, Massachusetts (United States)

    1997-12-31

    Predictive maintenance has gained wide acceptance as a cost cutting strategy in modern industry. Condition monitoring by lubricant analysis is one of the basic tools of a predictive maintenance program along with vibration monitoring, performance monitoring and thermography. In today`s modern power generation, manufacturing, refinery, transportation, mining, and military operations, the cost of equipment maintenance, service, and lubricants are ever increasing. Parts, labor, equipment downtime and lubricant prices and disposal costs are a primary concern in a well run maintenance management program. Machine condition monitoring based on oil analysis has become a prerequisite in most maintenance programs. Few operations can afford not to implement a program if they wish to remain competitive, and in some cases, profitable. This presentation describes a comprehensive Machine Condition Monitoring Program based on oil analysis. Actual operational condition monitoring programs will be used to review basic components and analytical requirements. Case histories will be cited as examples of cost savings, reduced equipment downtime and increased efficiencies of maintenance programs through a well managed oil analysis program. (orig.)

  3. Oxygen and minority carrier lifetimes in N-and P-type AL0.2GA0.8AS grown by metal organics vapor phase epitaxy

    International Nuclear Information System (INIS)

    Zahraman, Khaled; Leroux, M.; Gibart, P.; Zaidi, M.A.; Bremond, G.; Guillot, G.

    2000-01-01

    author.The minority carrier lifetimes in Al x Ga 1-x As grown by Metal-Organics Vapor Phase Epitaxy (MOVPE) is generally lower than in GaAs. This is believed to be due to oxygen incorporation in the layers. We describe a study of radiative and non radiative minority carriers lifetimes in n-and p-type Al 0.2 Ga 0.8 As as a function of growth parameters, in correlation with oxygen concentration measurements and deep level transient spectroscopy (DLTS) studies. Long non radiative lifetimes and low oxygen contents are achieved using temperature growth. A main minority hole lifetime killer appears to be 0.4 eV deep O related electron trap detected by DLTS at concentrations three orders of magnitude lower than the atomic oxygen one. Record lifetimes in MOVPE grown n-and p-type Al 0.2 Ga 0.8 As are obtained. An Al 0.85 Ga 0.15 As/Al 0.2 Ga 0.8 As surface recombination velocity lower than 4.5x10 3 cm.s -1 is measured

  4. Predicting arsenic concentrations in groundwater of San Luis Valley, Colorado: implications for individual-level lifetime exposure assessment.

    Science.gov (United States)

    James, Katherine A; Meliker, Jaymie R; Buttenfield, Barbara E; Byers, Tim; Zerbe, Gary O; Hokanson, John E; Marshall, Julie A

    2014-08-01

    Consumption of inorganic arsenic in drinking water at high levels has been associated with chronic diseases. Risk is less clear at lower levels of arsenic, in part due to difficulties in estimating exposure. Herein we characterize spatial and temporal variability of arsenic concentrations and develop models for predicting aquifer arsenic concentrations in the San Luis Valley, Colorado, an area of moderately elevated arsenic in groundwater. This study included historical water samples with total arsenic concentrations from 595 unique well locations. A longitudinal analysis established temporal stability in arsenic levels in individual wells. The mean arsenic levels for a random sample of 535 wells were incorporated into five kriging models to predict groundwater arsenic concentrations at any point in time. A separate validation dataset (n = 60 wells) was used to identify the model with strongest predictability. Findings indicate that arsenic concentrations are temporally stable (r = 0.88; 95 % CI 0.83-0.92 for samples collected from the same well 15-25 years apart) and the spatial model created using ordinary kriging best predicted arsenic concentrations (ρ = 0.72 between predicted and observed validation data). These findings illustrate the value of geostatistical modeling of arsenic and suggest the San Luis Valley is a good region for conducting epidemiologic studies of groundwater metals because of the ability to accurately predict variation in groundwater arsenic concentrations.

  5. Prediction of toxic metals concentration using artificial intelligence techniques

    Science.gov (United States)

    Gholami, R.; Kamkar-Rouhani, A.; Doulati Ardejani, F.; Maleki, Sh.

    2011-12-01

    Groundwater and soil pollution are noted to be the worst environmental problem related to the mining industry because of the pyrite oxidation, and hence acid mine drainage generation, release and transport of the toxic metals. The aim of this paper is to predict the concentration of Ni and Fe using a robust algorithm named support vector machine (SVM). Comparison of the obtained results of SVM with those of the back-propagation neural network (BPNN) indicates that the SVM can be regarded as a proper algorithm for the prediction of toxic metals concentration due to its relative high correlation coefficient and the associated running time. As a matter of fact, the SVM method has provided a better prediction of the toxic metals Fe and Ni and resulted the running time faster compared with that of the BPNN.

  6. Nuclear lifetimes

    International Nuclear Information System (INIS)

    Caraca, J.M.G.

    1976-01-01

    The importance of the results obtained in experiments of measurement of lifetimes for a detailed knowledge of nuclear structure is referred. Direct methods of measurement of nuclear lifetimes are described, namely, electronic methods, recoil-distance method, doppler shift atenuation method and blocking-method. A brief reference is made to indirect methods for measurement of life-times

  7. Lifetime of organic photovoltaics

    DEFF Research Database (Denmark)

    Corazza, Michael; Krebs, Frederik C; Gevorgyan, Suren A.

    2015-01-01

    tests. Comparison of the indoor and outdoor lifetimes was performed by means of the o-diagram, which constitutes the initial steps towards establishing a method for predicting the lifetime of an organic photovoltaic device under real operational conditions based on a selection of accelerated indoor...

  8. LIFETIME PREDICTIONS OF TOXIC AND RADIOACTIVE WASTE DISPOSAL AND REMEDIATION SCHEMES

    International Nuclear Information System (INIS)

    Wesolowski, D.J.; Ewing, R.C.; Bruno, J.

    2005-01-01

    Nuclear power production epitomizes the need for predictive geoscience (Ewing, 2004). Current global carbon emissions of ∼7 Gt/y, largely from fossil fuel consumption, are expected to grow and result in a variety of adverse global effects, including acid rain, toxic smog, and hypothetically, sea level rise and increased frequency and severity of adverse weather conditions. One of the most reliable and sufficiently large alternative sources of energy is nuclear power, which currently provides about 17% of the world's electricity, equivalent to a reduction in carbon emissions of ∼0.5 Gt/y. The U.S. currently consumes ∼40% of the world's fossil fuel production, but generates only about 20% of it's electricity from nuclear plants. One major factor inhibiting increased power production form this source in the US. is the lack of a licensed repository for spent nuclear fuel, and Yucca Mountain is the only site being considered at this time. The licensing issue hinges on DOE's ability to present a credible case before the Nuclear Regulatory Commission that releases of radionuclides from the repository will not pose a threat to the accessible environment. This case is being built using a performance assessment model that incorporates a thermochemical database (EQ3/6) fed by experiments and theoretical developments in aqueous geochemistry and fluid rock interactions, coupled reaction/transport models which combine both the chemical and physical aspects of fluid and heat transport through porous and fractured media, geohazard and climate change models, and information gleaned from natural analogs. The assessment period is currently 10,000 years, but this has recently been challenged in a court of law, and may be extended to 300,000 years or more. Yucca Mountain has a design capacity that only marginally exceeds the current U.S. inventory of commercial spent fuel, currently stored on site at power plants through the country. Some analysts suggest that in order to have a

  9. Lifetime Tests on a High Ohms/Square Metalized High Crystalline Polypropylene Film Capacitor with Application to a Marx Modulator

    International Nuclear Information System (INIS)

    Kemp, Mark A.; Burkhart, Craig; Tang, Tao

    2010-01-01

    This paper presents accelerated lifetime tests on a polypropylene film capacitor. Experimental parameters (20% droop, 5 Hz repetition rate) simulate anticipated operating conditions encountered in the SLAC P2 Marx. Elevated film electric field stress is utilized as the acceleration parameter. Results indicate that, for the particular film of interest, a film stress of ∼290 V/μm corresponds to a 10 5 hour lifetime. In addition, the voltage scaling exponent for this film is 13.1.

  10. Predictive testing of performance of metals in HTR service environments

    International Nuclear Information System (INIS)

    Kondo, T.; Shindo, M.; Tamura, M.; Tsuji, H.; Kurata, Y.; Tsukada, T.

    1982-01-01

    Status of the material testing in simulated HTGR environment is reviewed with special attention focused on the methodology of the prediction of performance in long time. Importance of controlling effective chemical potentials relations in the material-environmental interface is stressed in regard of the complex inter-dependent kinetic relation between oxidation and carbon transport. Based on the recent experimental observations, proposals are made to establish some procedures for conservative prediction of the metal performance

  11. Lifetime prediction of EC, DPA, akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    NARCIS (Netherlands)

    Boers, M.N.; Klerk, W.P.C. de

    2005-01-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages

  12. Substance Abuse among High-Risk Sexual Offenders: Do Measures of Lifetime History of Substance Abuse Add to the Prediction of Recidivism over Actuarial Risk Assessment Instruments?

    Science.gov (United States)

    Looman, Jan; Abracen, Jeffrey

    2011-01-01

    There has been relatively little research on the degree to which measures of lifetime history of substance abuse add to the prediction of risk based on actuarial measures alone among sexual offenders. This issue is of relevance in that a history of substance abuse is related to relapse to substance using behavior. Furthermore, substance use has…

  13. Lifetime prediction of EC, DPA, Akardite II and MNA stabilized triple base propellants, comparison of heat generation rate and stabilizer consumption

    Energy Technology Data Exchange (ETDEWEB)

    Boers, Marco N.; Klerk, Willem (Wim) P.C. de [TNO Defence, Security and Safety, P. O. Box 45, 2280 AA Rijswijk ZH (Netherlands)

    2005-10-01

    A lifetime prediction study is carried out on four triple base propellant compositions by artificial ageing. The ageing effects are studied with High Performance Liquid Chromatography (HPLC) and Heat Flow Calorimetry (HFC) in order to find the most effective stabilizer and to evaluate the advantages and disadvantages of both methods. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  14. Modelling impacts of performance on the probability of reproducing, and thereby on productive lifespan, allow prediction of lifetime efficiency in dairy cows.

    Science.gov (United States)

    Phuong, H N; Blavy, P; Martin, O; Schmidely, P; Friggens, N C

    2016-01-01

    Reproductive success is a key component of lifetime efficiency - which is the ratio of energy in milk (MJ) to energy intake (MJ) over the lifespan, of cows. At the animal level, breeding and feeding management can substantially impact milk yield, body condition and energy balance of cows, which are known as major contributors to reproductive failure in dairy cattle. This study extended an existing lifetime performance model to incorporate the impacts that performance changes due to changing breeding and feeding strategies have on the probability of reproducing and thereby on the productive lifespan, and thus allow the prediction of a cow's lifetime efficiency. The model is dynamic and stochastic, with an individual cow being the unit modelled and one day being the unit of time. To evaluate the model, data from a French study including Holstein and Normande cows fed high-concentrate diets and data from a Scottish study including Holstein cows selected for high and average genetic merit for fat plus protein that were fed high- v. low-concentrate diets were used. Generally, the model consistently simulated productive and reproductive performance of various genotypes of cows across feeding systems. In the French data, the model adequately simulated the reproductive performance of Holsteins but significantly under-predicted that of Normande cows. In the Scottish data, conception to first service was comparably simulated, whereas interval traits were slightly under-predicted. Selection for greater milk production impaired the reproductive performance and lifespan but not lifetime efficiency. The definition of lifetime efficiency used in this model did not include associated costs or herd-level effects. Further works should include such economic indicators to allow more accurate simulation of lifetime profitability in different production scenarios.

  15. Evolution of thermally pulsing asymptotic giant branch stars. IV. Constraining mass loss and lifetimes of low mass, low metallicity AGB stars

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfield, Philip; Dalcanton, Julianne J.; Weisz, Daniel; Williams, Benjamin F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Marigo, Paola [Department of Physics and Astronomy G. Galilei, University of Padova, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Girardi, Léo; Gullieuszik, Marco [Osservatorio Astronomico di Padova—INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Bressan, Alessandro [Astrophysics Sector, SISSA, Via Bonomea 265, I-34136 Trieste (Italy); Dolphin, Andrew [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Aringer, Bernhard [Department of Astrophysics, University of Vienna, Turkenschanzstraße 17, A-1180 Wien (Austria)

    2014-07-20

    The evolution and lifetimes of thermally pulsating asymptotic giant branch (TP-AGB) stars suffer from significant uncertainties. In this work, we analyze the numbers and luminosity functions of TP-AGB stars in six quiescent, low metallicity ([Fe/H] ≲ –0.86) galaxies taken from the ACS Nearby Galaxy Survey Treasury sample, using Hubble Space Telescope (HST) photometry in both optical and near-infrared filters. The galaxies contain over 1000 TP-AGB stars (at least 60 per field). We compare the observed TP-AGB luminosity functions and relative numbers of TP-AGB and red giant branch (RGB) stars, N{sub TP-AGB}/N{sub RGB}, to models generated from different suites of TP-AGB evolutionary tracks after adopting star formation histories derived from the HST deep optical observations. We test various mass-loss prescriptions that differ in their treatments of mass loss before the onset of dust-driven winds (pre-dust). These comparisons confirm that pre-dust mass loss is important, since models that neglect pre-dust mass loss fail to explain the observed N{sub TP-AGB}/N{sub RGB} ratio or the luminosity functions. In contrast, models with more efficient pre-dust mass loss produce results consistent with observations. We find that for [Fe/H] ≲ –0.86, lower mass TP-AGB stars (M ≲ 1 M{sub ☉}) must have lifetimes of ∼0.5 Myr and higher masses (M ≲ 3 M{sub ☉}) must have lifetimes ≲ 1.2 Myr. In addition, assuming our best-fitting mass-loss prescription, we show that the third dredge-up has no significant effect on TP-AGB lifetimes in this mass and metallicity range.

  16. Lifetime measurements

    International Nuclear Information System (INIS)

    Fossan, D.B.; Warburton, E.K.

    1974-01-01

    Lifetime measurements are discussed, concentrating on the electronic technique, the recoil distance method (RDM), and the Doppler shift attenuation method (DSAM). A brief review of several indirect timing techniques is given, and their specific advantages and applicability are considered. The relationship between lifetimes of nuclear states and the nuclear structure information obtained from them is examined. A short discussion of channeling and microwave methods of lifetime measurement is presented. (23 figures, 171 references) (U.S.)

  17. Predictive modeling of reactive wetting and metal joining.

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, Frank B.

    2013-09-01

    The performance, reproducibility and reliability of metal joints are complex functions of the detailed history of physical processes involved in their creation. Prediction and control of these processes constitutes an intrinsically challenging multi-physics problem involving heating and melting a metal alloy and reactive wetting. Understanding this process requires coupling strong molecularscale chemistry at the interface with microscopic (diffusion) and macroscopic mass transport (flow) inside the liquid followed by subsequent cooling and solidification of the new metal mixture. The final joint displays compositional heterogeneity and its resulting microstructure largely determines the success or failure of the entire component. At present there exists no computational tool at Sandia that can predict the formation and success of a braze joint, as current capabilities lack the ability to capture surface/interface reactions and their effect on interface properties. This situation precludes us from implementing a proactive strategy to deal with joining problems. Here, we describe what is needed to arrive at a predictive modeling and simulation capability for multicomponent metals with complicated phase diagrams for melting and solidification, incorporating dissolutive and composition-dependent wetting.

  18. Lifetimes of heavy flavour particles

    International Nuclear Information System (INIS)

    Forty, R.

    1994-01-01

    The lifetimes of heavy-flavour hadrons are reviewed. After a brief discussion of the theoretical predictions, the problem of averaging lifetime measurements is discussed. The various experimental measurements are then presented and suitable averages performed. Charmed meson lifetimes are now measured to the few percent level, better that theory can predict, whilst for charmed baryons the lifetime hierarchy has been established for the first time. For beauty hadrons the lifetimes are measured at the 6-10 % level, and are in reasonable agreement with theoretical expectations. Beauty baryon studies ar just beginning. (author)

  19. Empirical prediction of optical transitions in metallic armchair SWCNTs

    Directory of Open Access Journals (Sweden)

    G. R. Ahmed Jamal

    2015-12-01

    Full Text Available In this work, a quick and effective method to calculate the second and third optical transition energies of metallic armchair single-wall carbon nanotubes (SWCNT is presented. In this proposed method, the transition energy of any armchair SWCNT can be predicted directly by knowing its one chiral index as both of its chiral indices are same. The predicted results are compared with recent experimental data and found to be accurate over a wide diameter range from 2 to 4.8 nm. The empirical equation proposed here is also compared with that proposed in earlier works. The proposed way may help the research works or applications where information of optical transitions of armchair metallic nanotubes is needed.

  20. Charmed particle lifetimes

    International Nuclear Information System (INIS)

    Rosner, J.L.

    1979-01-01

    Conventional estimates are reviewed for charmed particle lifetimes. Free-quark models give values of (a few) x 10 -13 sec to (a few) x 10 -12 sec. The shorter of these values also follows from an extrapolation based on D → Ke/sup nu/. Possible differences among the lifetimes and production rates of D 0 , D + , F + , C 0 + , the heavy lepton tau, and the fifth quark b are discussed. Extreme values of mixing angles in a six-quark model could extend charmed particle lifetimes by a factor of at most three from the above estimates, while shorter lifetimes than those predicted could occur for some species like D 0 or F + if their nonleptonic decays were enhanced. The predictions are discussed in the light of some current experimental results, and it is estimated that sigma(pp → charm) approx. = 10 μb at 400 GeV/c. 95 references

  1. Lifetime Prediction of Nano-Silica based Glass Fibre/Epoxy composite by Time Temperature Superposition Principle

    Science.gov (United States)

    Anand, Abhijeet; Banerjee, Poulami; Prusty, Rajesh Kumar; Ray, Bankin Chandra

    2018-03-01

    The incorporation of nano fillers in Fibre reinforced polymer (FRP) composites has been a source of experimentation for researchers. Addition of nano fillers has been found to improve mechanical, thermal as well as electrical properties of Glass fibre reinforced polymer (GFRP) composites. The in-plane mechanical properties of GFRP composite are mainly controlled by fibers and therefore exhibit good values. However, composite exhibits poor through-thickness properties, in which the matrix and interface are the dominant factors. Therefore, it is conducive to modify the matrix through dispersion of nano fillers. Creep is defined as the plastic deformation experienced by a material for a temperature at constant stress over a prolonged period of time. Determination of Master Curve using time-temperature superposition principle is conducive for predicting the lifetime of materials involved in naval and structural applications. This is because such materials remain in service for a prolonged time period before failure which is difficult to be kept marked. However, the failure analysis can be extrapolated from its behaviour in a shorter time at an elevated temperature as is done in master creep analysis. The present research work dealt with time-temperature analysis of 0.1% SiO2-based GFRP composites fabricated through hand-layup method. Composition of 0.1% for SiO2nano fillers with respect to the weight of the fibers was observed to provide optimized flexural properties. Time and temperature dependence of flexural properties of GFRP composites with and without nano SiO2 was determined by conducting 3-point bend flexural creep tests over a range of temperature. Stepwise isothermal creep tests from room temperature (30°C) to the glass transition temperature Tg (120°C) were performed with an alternative creep/relaxation period of 1 hour at each temperature. A constant stress of 40MPa was applied during the creep tests. The time-temperature superposition principle was

  2. Electro-thermal Modeling for Junction Temperature Cycling-Based Lifetime Prediction of a Press-Pack IGBT 3L-NPC-VSC Applied to Large Wind Turbines

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

    2011-01-01

    Reliability is a critical criterion for multi-MW wind turbines, which are being employed with increasing numbers in wind power plants, since they operate under harsh conditions and have high maintenance cost due to their remote locations. In this study, the wind turbine grid-side converter...... reliability is investigated regarding IGBT lifetime based on junction temperature cycling for the grid-side press-pack IGBT 3L-NPC-VSC, which is a state-of-the art high reliability solution. In order to acquire IGBT junction temperatures for given wind power profiles and to use them in IGBT lifetime...... prediction, the converter electro-thermal model including electrical, power loss, and dynamical thermal models is developed with the main focus on the thermal modeling regarding converter topology, switch technology, and physical structure. Moreover, these models are simplified for their practical...

  3. Lifetime measurements

    International Nuclear Information System (INIS)

    Poletti, A.R.

    1976-01-01

    Recent developments in experimental methods of measuring the lifetimes of excited nuclear states is reviewed in three main areas. (a) Doppler Shift Attenuation Measurements (DSAM) Times: 10 -14 - 10 -11 sec.; (b) Recoil Distance Measurements (RDM) Times: 10 -9 - 10 -12 sec.; (c) Direct Electronic Timing Times: down to 10 -10 sec.; A measurement of an excited state lifetime can answer a large number of different questions. Two examples are discussed: (a) The determination of the lifetime of an isomeric transition in 93 Tc and its use in determining an upper limit for the magnitude of the parity non-conserving matrix element - /Hsub(PN)/17/2 + >. (b) The dependence of the strength of M2 transitions on isospin in nuclei in the 1dsub(3/2) -1fsub(7/2) region. (author)

  4. Impact of Interface States and Bulk Carrier Lifetime on Photocapacitance of Metal/Insulator/GaN Structure for Ultraviolet Light Detection

    Science.gov (United States)

    Bidzinski, Piotr; Miczek, Marcin; Adamowicz, Boguslawa; Mizue, Chihoko; Hashizume, Tamotsu

    2011-04-01

    The influence of interface state density and bulk carrier lifetime on the dependencies of photocapacitance versus wide range of gate bias (-0.1 to -3 V) and light intensity (109 to 1020 photon cm-2 s-1) was studied for metal/insulator/n-GaN UV light photodetector by means of numerical simulations. The light detection limit and photocapacitance saturation were analyzed in terms of the interface charge and interface Fermi level for electrons and holes and effective interface recombination velocity. It was proven that the excess carrier recombination through interface states is the main reason of photocapacitance signal quenching. It was found that the photodetector can work in various modes (on-off or quantitative light measurement) adjusted by the gate bias. A comparison between experimental data and theoretical capacitance-light intensity characteristics was made. A new method for the determination of the interface state density distribution from capacitance-voltage-light intensity measurements was also proposed.

  5. Numerical Prediction of Springback Shape of Severely Bent Sheet Metal

    International Nuclear Information System (INIS)

    Iwata, Noritoshi; Murata, Atsunobu; Yogo, Yasuhiro; Tsutamori, Hideo; Niihara, Masatomo; Ishikura, Hiroshi; Umezu, Yasuyoshi

    2007-01-01

    In the sheet metal forming simulation, the shell element widely used is assumed as a plane stress state based on the Mindlin-Reissner theory. Numerical prediction with the conventional shell element is not accurate when the bending radius is small compared to the sheet thickness. The main reason is because the strain and stress formulation of the conventional shell element does not fit the actual phenomenon. In order to predict precisely the springback of a bent sheet with a severe bend, a measurement method for through-thickness strain has been proposed. The strain was formulated based on measurement results and calculation results from solid element. Through-thickness stress distribution was formulated based on the equilibrium. The proposed shell element based on the formulations was newly introduced into the FEM code. The accuracy of this method's prediction of the springback shape of two bent processes has been confirmed. As a result, it was found that the springback shape even in severe bending can be predicted with high accuracy. Moreover, the calculation time in the proposed shell element is about twice that in the conventional shell element, and has been shortened to about 1/20 compared to a solid element

  6. Lifetime occupational exposure to metals and welding fumes, and risk of glioma: a 7-country population-based case-control study.

    Science.gov (United States)

    Parent, Marie-Elise; Turner, Michelle C; Lavoué, Jérôme; Richard, Hugues; Figuerola, Jordi; Kincl, Laurel; Richardson, Lesley; Benke, Geza; Blettner, Maria; Fleming, Sarah; Hours, Martine; Krewski, Daniel; McLean, David; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Schüz, Joachim; Siemiatycki, Jack; van Tongeren, Martie; Cardis, Elisabeth

    2017-08-25

    Brain tumor etiology is poorly understood. Based on their ability to pass through the blood-brain barrier, it has been hypothesized that exposure to metals may increase the risk of brain cancer. Results from the few epidemiological studies on this issue are limited and inconsistent. We investigated the relationship between glioma risk and occupational exposure to five metals - lead, cadmium, nickel, chromium and iron- as well as to welding fumes, using data from the seven-country INTEROCC study. A total of 1800 incident glioma cases and 5160 controls aged 30-69 years were included in the analysis. Lifetime occupational exposure to the agents was assessed using the INTEROCC JEM, a modified version of the Finnish job exposure matrix FINJEM. In general, cases had a slightly higher prevalence of exposure to the various metals and welding fumes than did controls, with the prevalence among ever exposed ranging between 1.7 and 2.2% for cadmium to 10.2 and 13.6% for iron among controls and cases, respectively. However, in multivariable logistic regression analyses, there was no association between ever exposure to any of the agents and risk of glioma with odds ratios (95% confidence intervals) ranging from 0.8 (0.7-1.0) for lead to 1.1 (0.7-1.6) for cadmium. Results were consistent across models considering cumulative exposure or duration, as well as in all sensitivity analyses conducted. Findings from this large-scale international study provide no evidence for an association between occupational exposure to any of the metals under scrutiny or welding fumes, and risk of glioma.

  7. Systematically extracting metal- and solvent-related occupational information from free-text responses to lifetime occupational history questionnaires.

    Science.gov (United States)

    Friesen, Melissa C; Locke, Sarah J; Tornow, Carina; Chen, Yu-Cheng; Koh, Dong-Hee; Stewart, Patricia A; Purdue, Mark; Colt, Joanne S

    2014-06-01

    Lifetime occupational history (OH) questionnaires often use open-ended questions to capture detailed information about study participants' jobs. Exposure assessors use this information, along with responses to job- and industry-specific questionnaires, to assign exposure estimates on a job-by-job basis. An alternative approach is to use information from the OH responses and the job- and industry-specific questionnaires to develop programmable decision rules for assigning exposures. As a first step in this process, we developed a systematic approach to extract the free-text OH responses and convert them into standardized variables that represented exposure scenarios. Our study population comprised 2408 subjects, reporting 11991 jobs, from a case-control study of renal cell carcinoma. Each subject completed a lifetime OH questionnaire that included verbatim responses, for each job, to open-ended questions including job title, main tasks and activities (task), tools and equipment used (tools), and chemicals and materials handled (chemicals). Based on a review of the literature, we identified exposure scenarios (occupations, industries, tasks/tools/chemicals) expected to involve possible exposure to chlorinated solvents, trichloroethylene (TCE) in particular, lead, and cadmium. We then used a SAS macro to review the information reported by study participants to identify jobs associated with each exposure scenario; this was done using previously coded standardized occupation and industry classification codes, and a priori lists of associated key words and phrases related to possibly exposed tasks, tools, and chemicals. Exposure variables representing the occupation, industry, and task/tool/chemicals exposure scenarios were added to the work history records of the study respondents. Our identification of possibly TCE-exposed scenarios in the OH responses was compared to an expert's independently assigned probability ratings to evaluate whether we missed identifying

  8. Lifetime prediction of InGaZnO thin film transistor for the application of display device and BEOL-transistors

    Science.gov (United States)

    Kim, Sang Min; Cho, Won Ju; Yu, Chong Gun; Park, Jong Tae

    2018-04-01

    In this work, the lifetime prediction models of amorphous InGaZnO thin film transistors (a-IGZO TFTs) were suggested for the application of display device and BEOL (Back End Of line) transistors with embedded a-IGZO TFTs. Four different types of test devices according to the active layer thickness, source/drain electrode materials and thermal treatments have been used to verify the suggested model. The device lifetimes under high gate bias stress and hot carrier stress were extracted through fittings of the stretched-exponential equation for threshold voltage shifts and the current estimation method for drain current degradations. Our suggested lifetime prediction models could be used in any kinds of structures of a-IGZO TFTs for the application of display device and BEOL transistors. The a-IGZO TFTs with embedded ITO local conducting layer under source/drain is better for BEOL transistor application and a-IGZO TFTs with InGaZnO thin film as source/drain electrodes may be better for the application of display devices. From 1983 to 1985, he was a Researcher at Gold-Star Semiconductor, Inc., Korea, where he worked on the development of SRAM. He joined the Department of Electronics Engineering, University of Incheon, Incheon, Korea, in 1987, where he is a Professor. As a visiting scientist at Massachusetts Institute of Technology, Cambridge, in 1991, he conducted research in hot carrier reliability of CMOS. As a visiting scholar at University of California, Davis, in 2001, he conducted research on the device structure of Nano-scale SOI CMOS. His recent interests are device structure and reliability of Nano-scale CMOS devices, flash memory, and thin film transistors.

  9. Mining the bulk positron lifetime

    International Nuclear Information System (INIS)

    Aourag, H.; Guittom, A.

    2009-01-01

    We introduce a new approach to investigate the bulk positron lifetimes of new systems based on data-mining techniques. Through data mining of bulk positron lifetimes, we demonstrate the ability to predict the positron lifetimes of new semiconductors on the basis of available semiconductor data already studied. Informatics techniques have been applied to bulk positron lifetimes for different tetrahedrally bounded semiconductors in order to discover computational design rules. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Identification of a Critical Time with Acoustic Emission Monitoring during Static Fatigue Tests on Ceramic Matrix Composites: Towards Lifetime Prediction

    Directory of Open Access Journals (Sweden)

    Nathalie Godin

    2016-02-01

    Full Text Available Non-oxide fiber-reinforced ceramic-matrix composites are promising candidates for some aeronautic applications that require good thermomechanical behavior over long periods of time. This study focuses on the behavior of a SiCf/[Si-B-C] composite with a self-healing matrix at intermediate temperature under air. Static fatigue experiments were performed below 600 °C and a lifetime diagram is presented. Damage is monitored both by strain measurement and acoustic emission during the static fatigue experiments. Two methods of real-time analysis of associated energy release have been developed. They allow for the identification of a characteristic time that was found to be close to 55% of the measured rupture time. This critical time reflects a critical local energy release assessed by the applicability of the Benioff law. This critical aspect is linked to a damage phase where slow crack growth in fibers is prevailing leading to ultimate fracture of the composite.

  11. Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

    Directory of Open Access Journals (Sweden)

    Pasqualina Sacco

    Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

  12. Modelling chelate-Induced phytoextraction: functional models predicting bioavailability of metals in soil, metal uptake and shoot biomass

    Directory of Open Access Journals (Sweden)

    Pasqualina Sacco

    2006-06-01

    Full Text Available Chelate-induced phytoextraction of heavy metals from contaminated soils requires special care to determine, a priori, the best method of chelate application, in terms of both dose and timing. In fact, the chelate dose must assure the bioavailability of the metal to the plant without increasing leaching risk and giving toxic effects. Three mathematical models are here proposed for usefully interpreting the processes taking place: a increased soil bioavailability of metals by chelants; b metal uptake by plants; c variation in plant biomass. The models are implemented and validated using data from pot and lysimeter trials. Both the chelate dose and the time elapsed since its application affected metal bioavailability and plant response. Contrariwise, the distribution strategy (single vs. split application seems to produce significant differences both in plant growth and metal uptake, but not in soil metal bioavailability. The proposed models may help to understand and predict the chelate dose – effect relationship with less experimental work.

  13. Predicting toxic heavy metal movements in upper Sanyati catchment ...

    African Journals Online (AJOL)

    Water samples from boreholes located in areas where mining, mineral processing and agricultural activities were dominant, yielded the highest values of toxic heavy metals. Dilution Attenuation Factor (DAF) for each toxic heavy metal was calculated to observe metal behaviour along the contaminant path for each season.

  14. Approach to evaluation and prediction of lifetime characteristics of NPP valve on the basis of operation data

    International Nuclear Information System (INIS)

    Emelyanov, V.; Kamyshnikov, O.; Dovgalyuk, V.; Plying, B.

    1994-01-01

    The report contains brief description of the main activity stages for testing, evaluation and prediction of reliability factors (including characteristics and factors of longevity) for NPP operating equipment. Valves equipped with electric drive that are installed in level control system of steam generator in WWER-1000 reactor are taken as an example. Main emphasis is made on classification of failures which had taken place during operation, on detection of prevailing mechanisms of ageing and on assessment of operation factors of reliability and methods of their testing, assessment and prediction. Principles of product ageing parameters selection are briefly described as well as mathematic methods used for quantitative assessment of products reliability factors according to its operation data. The report includes considerations on procedure of operating evaluation, testing and prediction of complex unique equipment based on testing of state vectors path, probabilities of defining parameters to be tested characterizing operability of set components within the assumed boundaries written in design and operation documentation are components of the vectors mentioned above. 9 refs, 4 figs

  15. Standard coupling unification in SO(10), hybrid seesaw neutrino mass and leptogenesis, dark matter, and proton lifetime predictions

    Energy Technology Data Exchange (ETDEWEB)

    Parida, M.K.; Nayak, Bidyut Prava; Satpathy, Rajesh [Centre of Excellence in Theoretical and Mathematical Sciences,Siksha ‘O’ Anusandhan University,Khandagiri Square, Bhubaneswar 751030 (India); Awasthi, Ram Lal [Indian Institute of Science Education and Research,Knowledge City, Sector 81, SAS Nagar, Manauli 140306 (India)

    2017-04-12

    We discuss gauge coupling unification of SU(3){sub C}×SU(2){sub L}×U(1){sub Y} descending directly from non-supersymmetric SO(10) while providing solutions to the three outstanding problems of the standard model: neutrino masses, dark matter, and the baryon asymmetry of the universe. Conservation of matter parity as gauged discrete symmetry for the stability and identification of dark matter in the model calls for high-scale spontaneous symmetry breaking through 126{sub H} Higgs representation. This naturally leads to the hybrid seesaw formula for neutrino masses mediated by heavy scalar triplet and right-handed neutrinos. Being quadratic in the Majorana coupling, the seesaw formula predicts two distinct patterns of right-handed neutrino masses, one hierarchical and another not so hierarchical (or compact), when fitted with the neutrino oscillation data. Predictions of the baryon asymmetry via leptogenesis are investigated through the decays of both the patterns of RHν masses. A complete flavor analysis has been carried out to compute CP-asymmetries including washouts and solutions to Boltzmann equations have been utilised to predict the baryon asymmetry. The additional contribution to vertex correction mediated by the heavy left-handed triplet scalar is noted to contribute as dominantly as other Feynman diagrams. We have found successful predictions of the baryon asymmetry for both the patterns of right-handed neutrino masses. The SU(2){sub L} triplet fermionic dark matter at the TeV scale carrying even matter parity is naturally embedded into the non-standard fermionic representation 45{sub F} of SO(10). In addition to the triplet scalar and the triplet fermion, the model needs a nonstandard color octet fermion of mass ∼5×10{sup 7} GeV to achieve precision gauge coupling unification at the GUT mass scale M{sub U}{sup 0}=10{sup 15.56} GeV. Threshold corrections due to superheavy components of 126{sub H} and other representations are estimated and found to be

  16. A quantitative in vitro method to predict the adhesion lifetime of diamond-like carbon thin films on biomedical implants.

    Science.gov (United States)

    Falub, Claudiu Valentin; Thorwarth, Götz; Affolter, Christian; Müller, Ulrich; Voisard, Cyril; Hauert, Roland

    2009-10-01

    A quantitative method using Rockwell C indentation was developed to study the adhesion of diamond-like carbon (DLC) protective coatings to the CoCrMo biomedical implant alloy when immersed in phosphate-buffered saline (PBS) solution at 37 degrees C. Two kinds of coatings with thicknesses ranging from 0.5 up to 16 microns were investigated, namely DLC and DLC/Si-DLC, where Si-DLC denotes a 90 nm thick DLC interlayer containing Si. The time-dependent delamination of the coating around the indentation was quantified by means of optical investigations of the advancing crack front and calculations of the induced stress using the finite element method (FEM). The cause of delamination for both types of coatings was revealed to be stress-corrosion cracking (SCC) of the interface material. For the DLC coating a typical SCC behavior was observed, including a threshold region (60J m(-2)) and a "stage 1" crack propagation with a crack-growth exponent of 3.0, comparable to that found for ductile metals. The DLC/Si-DLC coating exhibits an SCC process with a crack-growth exponent of 3.3 and a threshold region at 470 Jm(-2), indicating an adhesion in PBS at 37 degrees C that is about eight times better than that of the DLC coating. The SCC curves were fitted to the reaction controlled model typically used to explain the crack propagation in bulk soda lime glass. As this model falls short of accurately describing all the SCC curves, limitations of its application to the interface between a brittle coating and a ductile substrate are discussed.

  17. Lifetime spectroscopy a method of defect characterization in silicon for photovoltaic applications

    CERN Document Server

    Rein, Stefan

    2005-01-01

    Lifetime spectroscopy is one of the most sensitive diagnostic tools for the identification and analysis of impurities in semiconductors. Since it is based on the recombination process, it provides insight into precisely those defects that are relevant to semiconductor devices such as solar cells. This book introduces a transparent modeling procedure that allows a detailed theoretical evaluation of the spectroscopic potential of the different lifetime spectroscopic techniques. The various theoretical predictions are verified experimentally with the context of a comprehensive study on different metal impurities. The quality and consistency of the spectroscopic results, as explained here, confirms the excellent performance of lifetime spectroscopy.

  18. Multiple metals predict prolactin and thyrotropin (TSH) levels in men

    Energy Technology Data Exchange (ETDEWEB)

    Meeker, John D., E-mail: meekerj@umich.edu [Department of Environmental Health Sciences, University of Michigan School of Public Health, 6635 SPH Tower, 109 S. Observatory St., Ann Arbor, MI 48109 (United States); Rossano, Mary G. [Department of Animal and Food Sciences, University of Kentucky, Lexington, KY (United States); Protas, Bridget [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Diamond, Michael P.; Puscheck, Elizabeth [Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI (United States); Daly, Douglas [Grand Rapids Fertility and IVF, Grand Rapids, MI (United States); Paneth, Nigel [Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States); Wirth, Julia J. [Department of Epidemiology, Michigan State University, East Lansing, MI (United States); Department of Obstetrics and Gynecology, Michigan State University, East Lansing, MI (United States)

    2009-10-15

    Exposure to a number of metals can affect neuroendocrine and thyroid signaling, which can result in adverse effects on development, behavior, metabolism, reproduction, and other functions. The present study assessed the relationship between metal concentrations in blood and serum prolactin (PRL) and thyrotropin (TSH) levels, markers of dopaminergic, and thyroid function, respectively, among men participating in a study of environmental influences on male reproductive health. Blood samples from 219 men were analyzed for concentrations of 11 metals and serum levels of PRL and TSH. In multiple linear regression models adjusted for age, BMI and smoking, PRL was inversely associated with arsenic, cadmium, copper, lead, manganese, molybdenum, and zinc, but positively associated with chromium. Several of these associations (Cd, Pb, Mo) are consistent with limited studies in humans or animals, and a number of the relationships (Cr, Cu, Pb, Mo) remained when additionally considering multiple metals in the model. Lead and copper were associated with non-monotonic decrease in TSH, while arsenic was associated with a dose-dependent increase in TSH. For arsenic these findings were consistent with recent experimental studies where arsenic inhibited enzymes involved in thyroid hormone synthesis and signaling. More research is needed for a better understanding of the role of metals in neuroendocrine and thyroid function and related health implications.

  19. Multiple metals predict prolactin and thyrotropin (TSH) levels in men

    International Nuclear Information System (INIS)

    Meeker, John D.; Rossano, Mary G.; Protas, Bridget; Diamond, Michael P.; Puscheck, Elizabeth; Daly, Douglas; Paneth, Nigel; Wirth, Julia J.

    2009-01-01

    Exposure to a number of metals can affect neuroendocrine and thyroid signaling, which can result in adverse effects on development, behavior, metabolism, reproduction, and other functions. The present study assessed the relationship between metal concentrations in blood and serum prolactin (PRL) and thyrotropin (TSH) levels, markers of dopaminergic, and thyroid function, respectively, among men participating in a study of environmental influences on male reproductive health. Blood samples from 219 men were analyzed for concentrations of 11 metals and serum levels of PRL and TSH. In multiple linear regression models adjusted for age, BMI and smoking, PRL was inversely associated with arsenic, cadmium, copper, lead, manganese, molybdenum, and zinc, but positively associated with chromium. Several of these associations (Cd, Pb, Mo) are consistent with limited studies in humans or animals, and a number of the relationships (Cr, Cu, Pb, Mo) remained when additionally considering multiple metals in the model. Lead and copper were associated with non-monotonic decrease in TSH, while arsenic was associated with a dose-dependent increase in TSH. For arsenic these findings were consistent with recent experimental studies where arsenic inhibited enzymes involved in thyroid hormone synthesis and signaling. More research is needed for a better understanding of the role of metals in neuroendocrine and thyroid function and related health implications.

  20. Predicting Metal Speciation & Bioavailability via Estimation of Metal-Organic Thermodynamic Properties

    Science.gov (United States)

    Prasad, A.; Howells, A. E.; Shock, E.

    2017-12-01

    The biological fate of any metal depends on its chemical form in the environment. Arsenic for example, is extremely toxic in the form of inorganic As+3 but completely benign in the organic form of arsenobetaine. Thus, given an exhaustive set of reactions and their equilibrium constants (logK), the bioavailability of any metal can be obtained for blood plasma, hydrothermal fluids or any system of interest. While many data exist for metal-inorganic ligands, logK data covering the temperature range of life for metal-organic complexes are sparse. Hence, we decided to estimate metal-organic logK values from correlations with the commonly available values of ligand pKa. Metal ion specific correlations were made with ligands classified according to their electron donor atoms, denticity and other chemical factors. While this approach has been employed before (Carbonaro et al. 2007, GCA 71, 3958-3968), new correlations were developed that provide estimates even when no metal-organic logK is available. In addition, we have used the same methods to make estimates of metal-organic entropy of association (ΔaS), which can provide logK for any temperature of biological relevance. Our current correlations employ logK and ΔaS data from 30 metal ions (like the biologically relevant Fe+3 & Zn+2) and 74 ligands (like formate and ethylenediamine), which can be expanded to estimate the metal-ligand reaction properties for these 30 metal ions with a possibly limitless number of ligands that may belong to our categories of ligands. With the help of such data, copper speciation was obtained for a defined growth medium for methanotrophs employed by Morton et al. (2000, AEM 66, 1730-1733) that agrees with experimental measurements showing that the free metal ion may not be the bioavailable form in all conditions. These results encourage us to keep filling the gaps in metal-organic logK data and continue finding relationships between biological responses (like metal-accumulation ratios

  1. Predicting the phytoextraction duration to remediate heavy metal contaminated soils

    NARCIS (Netherlands)

    Koopmans, G.F.; Römkens, P.F.A.M.; Song, J.; Temminghoff, E.J.M.; Japenga, J.

    2007-01-01

    The applicability of phytoextraction to remediate soils contaminated with heavy metals (HMs) depends on, amongst others, the duration before remediation is completed. The impact of changes in the HM content in soil occurring during remediation on plant uptake has to be considered in order to obtain

  2. Heterogeneous associations between smoking and a wide range of initial presentations of cardiovascular disease in 1937360 people in England: lifetime risks and implications for risk prediction.

    Science.gov (United States)

    Pujades-Rodriguez, Mar; George, Julie; Shah, Anoop Dinesh; Rapsomaniki, Eleni; Denaxas, Spiros; West, Robert; Smeeth, Liam; Timmis, Adam; Hemingway, Harry

    2015-02-01

    It is not known how smoking affects the initial presentation of a wide range of chronic and acute cardiovascular diseases (CVDs), nor the extent to which associations are heterogeneous. We estimated the lifetime cumulative incidence of 12 CVD presentations, and examined associations with smoking and smoking cessation. Cohort study of 1.93 million people aged ≥30years, with no history of CVD, in 1997-2010. Individuals were drawn from linked electronic health records in England, covering primary care, hospitalizations, myocardial infarction (MI) registry and cause-specific mortality (the CALIBER programme). During 11.6 million person-years of follow-up, 114859 people had an initial non-fatal or fatal CVD presentation. By age 90 years, current vs never smokers' lifetime risks varied from 0.4% vs 0.2% for subarachnoid haemorrhage (SAH), to 8.9% vs 2.6% for peripheral arterial disease (PAD). Current smoking showed no association with cardiac arrest or sudden cardiac death [hazard ratio (HR)=1.04, 95% confidence interval (CI) 0.91-1.19).The strength of association differed markedly according to disease type: stable angina (HR=1.08, 95% CI 1.01-1.15),transient ischaemic attack (HR=1.41, 95% CI 1.28-1.55), unstable angina (HR=1.54, 95% CI 1.38-1.72), intracerebral haemorrhage (HR=1.61, 95% CI 1.37-1.89), heart failure (HR=1.62, 95% CI 1.47-1.79), ischaemic stroke (HR=1.90, 95% CI 1.72-2.10), MI (HR=2.32, 95% CI 2.20-2.45), SAH (HR= 2.70, 95% CI 2.27-3.21), PAD (HR=5.16, 95% CI 4.80-5.54) and abdominal aortic aneurysm (AAA) (HR=5.18, 95% CI 4.61-5.82). Population-attributable fractions were lower for women than men for unheralded coronary death, ischaemic stroke, PAD and AAA. Ten years after quitting smoking, the risks of PAD, AAA (in men) and unheralded coronary death remained increased (HR=1.36, 1.47 and 2.74, respectively). The heterogeneous associations of smoking with different CVD presentations suggests different underlying mechanisms and have important

  3. The Extent and Prediction of Heavy Metal Pollution in Soils of Shahrood and Damghan, Iran.

    Science.gov (United States)

    Sakizadeh, Mohamad; Mirzaei, Rouhollah; Ghorbani, Hadi

    2015-12-01

    The levels of 12 heavy metals (Ag, Ba, Be, Cd, Co, Cr, Cu, Ni, Pb, Tl, V, Zn) were considered in 229 soil samples in Semnan Province, Iran. To discriminate between natural and anthropogenic inputs of heavy metals, factor analysis was used. Seven factors accounting for 90.5 % of the total variance were extracted. The mining and agricultural activities along with geogenic sources have been attributed as the main causes of the levels of heavy metals in the study area. The partial least squares regression was utilized to predict the level of soil pollution index (SPI) considering the concentrations of 12 heavy metals. The eigenvectors from the first three PLS represented more than 98 % of the overall variance. The correlation coefficient between the observed and predicted SPI was 0.99 indicating the high efficiency of this method. The resultant coefficient of determination for three PLS components was 0.984 confirming the predictive ability of this method.

  4. Ductility prediction of substrate-supported metal layers based on rate-independent crystal plasticity theory

    Directory of Open Access Journals (Sweden)

    Akpama Holanyo K.

    2016-01-01

    Full Text Available In this paper, both the bifurcation theory and the initial imperfection approach are used to predict localized necking in substrate-supported metal layers. The self-consistent scale-transition scheme is used to derive the mechanical behavior of a representative volume element of the metal layer from the behavior of its microscopic constituents (the single crystals. The mechanical behavior of the elastomer substrate follows the neo-Hookean hyperelastic model. The adherence between the two layers is assumed to be perfect. Through numerical results, it is shown that the limit strains predicted by the initial imperfection approach tend towards the bifurcation predictions when the size of the geometric imperfection in the metal layer vanishes. Also, it is shown that the addition of an elastomer layer to a metal layer enhances ductility.

  5. Predicting Mechanical Properties of Metal Matrix Syntactic Foams Reinforced with Ceramic Spheres

    Science.gov (United States)

    2012-01-01

    predicting the properties of interest listed above. Kiser et al. [12] extended a metal foam model to account for ceramic reinforcement to predict the...Daoud A. J Alloys Compd. 2009; 487:618. 11. Drury WJ, Rickles SA, Sanders Jr TH, Cochran JK. In Light-Weight Alloys for Aerospace Applications, ed. Loe

  6. Prediction of metal corrosion using feed-forward neural networks

    International Nuclear Information System (INIS)

    Mahjani, M.G.; Jalili, S.; Jafarian, M.; Jaberi, A.

    2004-01-01

    The reliable prediction of corrosion behavior for the effective control of corrosion is a fundamental requirement. Since real world corrosion never seems to involve quite the same conditions that have previously been tested, using corrosion literature does not provide the necessary answers. In order to provide a methodology for predicting corrosion in real and complex situations, artificial neural networks can be utilized. Feed-forward artificial neural network (FFANN) is an information-processing paradigm inspired by the way the densely interconnected, parallel structure of the human brain process information.The aim of the present work is to predict corrosion behavior in critical conditions, such as industrial applications, based on some laboratory experimental data. Electrochemical behavior of stainless steel in different conditions were studied, using polarization technique and Tafel curves. Back-propagation neural networks models were developed to predict the corrosion behavior. The trained networks result in predicted value in good comparison to the experimental data. They have generally been claimed to be successful in modeling the corrosion behavior. The results are presented in two tables. Table 1 gives corrosion behavior of stainless-steel as a function of pH and CuSO 4 concentration and table 2 gives corrosion behavior of stainless - steel as a function of electrode surface area and CuSO 4 concentration. (authors)

  7. Predicting trace metal solubility and fractionation in Urban soils from isotopic exchangeability

    International Nuclear Information System (INIS)

    Mao, L.C.; Young, S.D.; Tye, A.M.; Bailey, E.H.

    2017-01-01

    Metal-salt amended soils (MA, n = 23), and historically-contaminated urban soils from two English cities (Urban, n = 50), were investigated to assess the effects of soil properties and contaminant source on metal lability and solubility. A stable isotope dilution method, with and without a resin purification step, was used to measure the lability of Cd, Cu, Ni, Pb and Zn. For all five metals in MA soils, lability (%E-values) could be reasonably well predicted from soil pH value with a simple logistic equation. However, there was evidence of continuing time-dependent fixation of Cd and Zn in the MA soils, following more than a decade of storage under air-dried conditions, mainly in high pH soils. All five metals in MA soils remained much more labile than in Urban soils, strongly indicating an effect of contaminant source on metal lability in the latter. Metal solubility was predicted for both sets of soil by the geochemical speciation model WHAM-VII, using E-value as an input variable. For soils with low metal solution concentrations, over-estimation of Cd, Ni and Zn solubility was associated with binding to the Fe oxide fraction while accurate prediction of Cu solubility was dependent on humic acid content. Lead solubility was most poorly described, especially in the Urban soils. Generally, slightly poorer estimation of metal solubility was observed in Urban soils, possibly due to a greater incidence of high pH values. The use of isotopically exchangeable metal to predict solubility is appropriate both for historically contaminated soils and where amendment with soluble forms of metal is used, as in toxicological trials. However, the major limitation to predicting solubility may lie with the accuracy of model input variables such as humic acid and Fe oxide contents where there is often a reliance on relatively crude analytical estimations of these variables. Trace metal reactivity in urban soils depends on both soil properties and the original source material

  8. Uncertainties associated with lacking data for predictions of solid-solution partitioning of metals in soil

    International Nuclear Information System (INIS)

    Le, T.T. Yen; Hendriks, A. Jan

    2014-01-01

    Soil properties, i.e., pH and contents of soil organic matter (SOM), dissolved organic carbon (DOC), clay, oxides, and reactive metals, are required inputs to both mechanistic and empirical modeling in assessing metal solid-solution partitioning. Several of these properties are rarely measured in site-specific risk assessment. We compared the uncertainties induced by lacking data on these soil properties in estimating metal soil solution concentrations. The predictions by the Orchestra framework were more sensitive to lacking soil property data than the predictions by the transfer functions. The deviations between soil solution concentrations of Cd, Ni, Zn, Ba, and Co estimated with measured SOM and those estimated with generic SOM by the Orchestra framework were about 10 times larger than the deviations in the predictions by the transfer functions. High uncertainties were induced by lacking data in assessing solid-solution partitioning of oxy-anions like As, Mo, Sb, Se, and V. Deviations associated with lacking data in predicting soil solution concentrations of these metals by the Orchestra framework reached three-to-six orders of magnitude. The solid-solution partitioning of metal cations was strongly influenced by pH and contents of organic matter, oxides, and reactive metals. Deviations of more than two orders of magnitude were frequently observed between the estimates of soil solution concentrations with the generic values of these properties and the estimates based on the measured data. Reliable information on these properties is preferred to be included in the assessment by either the Orchestra framework or transfer functions. - Highlights: • Estimates of metal solid-solution partitioning sensitive to soil property data. • Uncertainty mainly due to lacking reactive metal contents, pH, and organic matter. • Soil solution concentrations of oxy-anions highly influenced by oxide contents. • Clay contents had least effects on solid-solution partitioning

  9. Uncertainties associated with lacking data for predictions of solid-solution partitioning of metals in soil

    Energy Technology Data Exchange (ETDEWEB)

    Le, T.T. Yen, E-mail: YenLe@science.ru.nl; Hendriks, A. Jan

    2014-08-15

    Soil properties, i.e., pH and contents of soil organic matter (SOM), dissolved organic carbon (DOC), clay, oxides, and reactive metals, are required inputs to both mechanistic and empirical modeling in assessing metal solid-solution partitioning. Several of these properties are rarely measured in site-specific risk assessment. We compared the uncertainties induced by lacking data on these soil properties in estimating metal soil solution concentrations. The predictions by the Orchestra framework were more sensitive to lacking soil property data than the predictions by the transfer functions. The deviations between soil solution concentrations of Cd, Ni, Zn, Ba, and Co estimated with measured SOM and those estimated with generic SOM by the Orchestra framework were about 10 times larger than the deviations in the predictions by the transfer functions. High uncertainties were induced by lacking data in assessing solid-solution partitioning of oxy-anions like As, Mo, Sb, Se, and V. Deviations associated with lacking data in predicting soil solution concentrations of these metals by the Orchestra framework reached three-to-six orders of magnitude. The solid-solution partitioning of metal cations was strongly influenced by pH and contents of organic matter, oxides, and reactive metals. Deviations of more than two orders of magnitude were frequently observed between the estimates of soil solution concentrations with the generic values of these properties and the estimates based on the measured data. Reliable information on these properties is preferred to be included in the assessment by either the Orchestra framework or transfer functions. - Highlights: • Estimates of metal solid-solution partitioning sensitive to soil property data. • Uncertainty mainly due to lacking reactive metal contents, pH, and organic matter. • Soil solution concentrations of oxy-anions highly influenced by oxide contents. • Clay contents had least effects on solid-solution partitioning

  10. Promising half-metallicity in ductile NbF3: a first-principles prediction.

    Science.gov (United States)

    Yang, Bo; Wang, Junru; Liu, Xiaobiao; Zhao, Mingwen

    2018-02-14

    Materials with half-metallicity are long desired in spintronics. Using first-principles calculations, we predicted that the already-synthesized NbF 3 crystal is a promising half-metal with a large exchange splitting and stable ferromagnetism. The mechanical stability, ductility and softness of the NbF 3 crystal were confirmed by its elastic constants and moduli. The Curie temperature (T C = 120 K) estimated from the Monte Carlo simulations based on the 3D Ising model is above the liquid nitrogen temperature (78 K). The ferromagnetism and half-metallicity can be preserved on the surfaces of NbF 3 . The NbOF 2 formed by substituting F with O atoms, however, has an antiferromagnetic ground state and a normal metallic band structure. This work opens an avenue for half-metallic materials and may find applications in spintronic devices.

  11. Metal accumulation in the earthworm Lumbricus rubellus. Model predictions compared to field data

    Science.gov (United States)

    Veltman, K.; Huijbregts, M.A.J.; Vijver, M.G.; Peijnenburg, W.J.G.M.; Hobbelen, P.H.F.; Koolhaas, J.E.; van Gestel, C.A.M.; van Vliet, P.C.J.; Jan, Hendriks A.

    2007-01-01

    The mechanistic bioaccumulation model OMEGA (Optimal Modeling for Ecotoxicological Applications) is used to estimate accumulation of zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) in the earthworm Lumbricus rubellus. Our validation to field accumulation data shows that the model accurately predicts internal cadmium concentrations. In addition, our results show that internal metal concentrations in the earthworm are less than linearly (slope < 1) related to the total concentration in soil, while risk assessment procedures often assume the biota-soil accumulation factor (BSAF) to be constant. Although predicted internal concentrations of all metals are generally within a factor 5 compared to field data, incorporation of regulation in the model is necessary to improve predictability of the essential metals such as zinc and copper. ?? 2006 Elsevier Ltd. All rights reserved.

  12. A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

    DEFF Research Database (Denmark)

    Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

    2015-01-01

    accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

  13. Development of METAL-ACTIVE SITE and ZINCCLUSTER tool to predict active site pockets.

    Science.gov (United States)

    Ajitha, M; Sundar, K; Arul Mugilan, S; Arumugam, S

    2018-03-01

    The advent of whole genome sequencing leads to increasing number of proteins with known amino acid sequences. Despite many efforts, the number of proteins with resolved three dimensional structures is still low. One of the challenging tasks the structural biologists face is the prediction of the interaction of metal ion with any protein for which the structure is unknown. Based on the information available in Protein Data Bank, a site (METALACTIVE INTERACTION) has been generated which displays information for significant high preferential and low-preferential combination of endogenous ligands for 49 metal ions. User can also gain information about the residues present in the first and second coordination sphere as it plays a major role in maintaining the structure and function of metalloproteins in biological system. In this paper, a novel computational tool (ZINCCLUSTER) is developed, which can predict the zinc metal binding sites of proteins even if only the primary sequence is known. The purpose of this tool is to predict the active site cluster of an uncharacterized protein based on its primary sequence or a 3D structure. The tool can predict amino acids interacting with a metal or vice versa. This tool is based on the occurrence of significant triplets and it is tested to have higher prediction accuracy when compared to that of other available techniques. © 2017 Wiley Periodicals, Inc.

  14. Predicting supramolecular self-assembly on reconstructed metal surfaces

    Science.gov (United States)

    Roussel, Thomas J.; Barrena, Esther; Ocal, Carmen; Faraudo, Jordi

    2014-06-01

    The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule-molecule interactions are enhanced in a way that long-range order is promoted. Also, the presence of a distortion in a reconstructed surface pattern not only induces the presence of long-range order but also is able to drive the organization of DIP into two coexisting homochiral domains, in quantitative agreement with STM experiments. On the other hand, only short range order is obtained in other reconstructions of the Au(111) surface. The simulation strategy opens interesting perspectives to tune the supramolecular structure by simulation design and surface engineering if choosing the right molecular building blocks and stabilising the chosen reconstruction pattern.The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule

  15. Predicting life-time and regular cannabis use during adolescence; the roles of temperament and peer substance use: the TRAILS study

    NARCIS (Netherlands)

    Creemers, H.E.; Dijkstra, J.K.; Vollebergh, W.A.M.; Ormel, J.; Verhulst, F.C.; Huizink, A.C.

    2010-01-01

    Aims The aim of the present study was to determine the mediating role of affiliation with cannabis-using peers in the pathways from various dimensions of temperament to life-time cannabis use, and to determine if these associations also contributed to the development of regular cannabis

  16. PERFORM 60: Prediction of the effects of radiation for reactor pressure vessel and in-core materials using multi-scale modelling - 60 years foreseen plant lifetime

    International Nuclear Information System (INIS)

    Al Mazouzi, A.; Alamo, A.; Lidbury, D.; Moinereau, D.; Van Dyck, S.

    2011-01-01

    Highlights: → Multi-scale and multi-physics modelling are adopted by PERFORM 60 to predict irradiation damage in nuclear structural materials. → PERFORM 60 allows to Consolidate the community and improve the interaction between universities/industries and safety authorities. → Experimental validation at the relevant scale is a key for developing the multi-scale modelling methodology. - Abstract: In nuclear power plants, materials undergo degradation due to severe irradiation conditions that may limit their operational lifetime. Utilities that operate these reactors need to quantify the ageing and potential degradation of certain essential structures of the power plant to ensure their safe and reliable operation. So far, the monitoring and mitigation of these degradation phenomena rely mainly on long-term irradiation programs in test reactors as well as on mechanical or corrosion testing in specialized hot cells. Continuous progress in the physical understanding of the phenomena involved in irradiation damage and progress in computer sciences have now made possible the development of multi-scale numerical tools able to simulate the materials behaviour in a nuclear environment. Indeed, within the PERFECT project of the EURATOM framework program (FP6), a first step has been successfully reached through the development of a simulation platform that contains several advanced numerical tools aiming at the prediction of irradiation damage in both the reactor pressure vessel (RPV) and its internals using available, state-of-the-art-knowledge. These tools allow simulation of irradiation effects on the nanostructure and the constitutive behaviour of the RPV low alloy steels, as well as their fracture mechanics properties. For the more highly irradiated reactor internals, which are commonly produced using austenitic stainless steels, the first partial models were established, describing radiation effects on the nanostructure and providing a first description of the

  17. Springback prediction in sheet metal forming process based on the hybrid SA

    International Nuclear Information System (INIS)

    Guo Yuqin; Jiang Hong; Wang Xiaochun; Li Fuzhu

    2005-01-01

    In terms of the intensive similarity between the sheet metal forming-springback process and that of the annealing of metals, it is suggested that the simulation of the sheet metal forming process is performed with the Nonlinear FEM and the springback prediction is implemented by solving the large-scale combinational optimum problem established on the base of the energy descending and balancing in deformed part. The BFGS-SA hybrid SA approach is proposed to solve this problem and improve the computing efficiency of the traditional SA and its capability of obtaining the global optimum solution. At the same time, the correlative annealing strategies for the SA algorithm are determined in here. By comparing the calculation results of sample part with those of experiment measurement at the specified sections, the rationality of the schedule of springback prediction used and the validity of the BFGS-SA algorithm proposed are verified

  18. Microstructure-based approach for predicting crack initiation and early growth in metals.

    Energy Technology Data Exchange (ETDEWEB)

    Cox, James V.; Emery, John M.; Brewer, Luke N.; Reedy, Earl David, Jr.; Puskar, Joseph David; Bartel, Timothy James; Dingreville, Remi P. M.; Foulk, James W., III; Battaile, Corbett Chandler; Boyce, Brad Lee

    2009-09-01

    Fatigue cracking in metals has been and is an area of great importance to the science and technology of structural materials for quite some time. The earliest stages of fatigue crack nucleation and growth are dominated by the microstructure and yet few models are able to predict the fatigue behavior during these stages because of a lack of microstructural physics in the models. This program has developed several new simulation tools to increase the microstructural physics available for fatigue prediction. In addition, this program has extended and developed microscale experimental methods to allow the validation of new microstructural models for deformation in metals. We have applied these developments to fatigue experiments in metals where the microstructure has been intentionally varied.

  19. Prediction of contact mechanics in metal-on-metal Total Hip Replacement for parametrically comprehensive designs and loads.

    Science.gov (United States)

    Donaldson, Finn E; Nyman, Edward; Coburn, James C

    2015-07-16

    Manufacturers and investigators of Total Hip Replacement (THR) bearings require tools to predict the contact mechanics resulting from diverse design and loading parameters. This study provides contact mechanics solutions for metal-on-metal (MoM) bearings that encompass the current design space and could aid pre-clinical design optimization and evaluation. Stochastic finite element (FE) simulation was used to calculate the head-on-cup contact mechanics for five thousand combinations of design and loading parameters. FE results were used to train a Random Forest (RF) surrogate model to rapidly predict the contact patch dimensions, contact area, pressures and plastic deformations for arbitrary designs and loading. In addition to widely observed polar and edge contact, FE results included ring-polar, asymmetric-polar, and transitional categories which have previously received limited attention. Combinations of design and load parameters associated with each contact category were identified. Polar contact pressures were predicted in the range of 0-200 MPa with no permanent deformation. Edge loading (with subluxation) was associated with pressures greater than 500 MPa and induced permanent deformation in 83% of cases. Transitional-edge contact (with little subluxation) was associated with intermediate pressures and permanent deformation in most cases, indicating that, even with ideal anatomical alignment, bearings may face extreme wear challenges. Surrogate models were able to accurately predict contact mechanics 18,000 times faster than FE analyses. The developed surrogate models enable rapid prediction of MoM bearing contact mechanics across the most comprehensive range of loading and designs to date, and may be useful to those performing bearing design optimization or evaluation. Published by Elsevier Ltd.

  20. MCTBI: a web server for predicting metal ion effects in RNA structures.

    Science.gov (United States)

    Sun, Li-Zhen; Zhang, Jing-Xiang; Chen, Shi-Jie

    2017-08-01

    Metal ions play critical roles in RNA structure and function. However, web servers and software packages for predicting ion effects in RNA structures are notably scarce. Furthermore, the existing web servers and software packages mainly neglect ion correlation and fluctuation effects, which are potentially important for RNAs. We here report a new web server, the MCTBI server (http://rna.physics.missouri.edu/MCTBI), for the prediction of ion effects for RNA structures. This server is based on the recently developed MCTBI, a model that can account for ion correlation and fluctuation effects for nucleic acid structures and can provide improved predictions for the effects of metal ions, especially for multivalent ions such as Mg 2+ effects, as shown by extensive theory-experiment test results. The MCTBI web server predicts metal ion binding fractions, the most probable bound ion distribution, the electrostatic free energy of the system, and the free energy components. The results provide mechanistic insights into the role of metal ions in RNA structure formation and folding stability, which is important for understanding RNA functions and the rational design of RNA structures. © 2017 Sun et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  1. Predicting the release of metals from ombrotrophic peat due to drought-induced acidification

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E.; Smith, E.J.; Lawlor, A.J.; Hughes, S.; Stevens, P.A

    2003-05-01

    Metals stored in peats can be remobilised by sulphuric acid, generated by the drought-induced oxidation of reduced sulphur. - Ombrotrophic peats in northern England and Scotland, close to industrial areas, have substantial contents of potentially toxic metals (Al, Ni, Cu, Zn, Cd and Pb) and of pollutant sulphur, all derived from atmospheric deposition. The peat sulphur, ordinarily in reduced form, may be converted to sulphuric acid under drought conditions, due to the entry of oxygen into the peats. The consequent lowering of soil solution pH is predicted to cause the release of metals held on ligand sites of the peat organic matter. The purpose of the present study was to explore, by simulation modelling, the extent of the metal response. Chemical variables (elemental composition, pH, metal contents) were measured for samples of ombrotrophic peats from three locations. Water extracts of the peats, and samples of local surface water, were also analysed, for pH, dissolved organic carbon (DOC) and metals. Metal release from peats due to acidification was demonstrated experimentally, and could be accounted for reasonably well using a speciation code (WHAM/Model VI). These data, together with information on metal and S deposition, and meteorology, were used to construct a simple description of peat hydrochemistry, based on WHAM/Model VI, that takes into account ion-binding by humic substances (assumed to be the 'active' constituents of the peat with respect to ion-binding). The model was used to simulate steady state situations that approximated the observed soil pH, metal pools and dissolved metal concentrations. Then, drought conditions were imposed, to generate increased concentrations of H{sub 2}SO{sub 4}, in line with those observed during the drought of 1995. The model calculations suggest that the pH will decrease from the initial steady state value of 4.3 to 3.3-3.6 during rewetting periods following droughts, depending upon assumptions about the

  2. Simple metal model for predicting uptake and chemical processes in sewage-fed aquaculture ecosystem

    DEFF Research Database (Denmark)

    Azanu, David; Jorgensen, Sven Erik; Darko, Godfred

    2016-01-01

    but not working properly for chromium and mercury. Additional processes, including precipitation of chromium and bio-magnification of methylmercury were introduced to explain concentration of chromium and mercury in fish. Comparison of measured and predicted metal concentration used for validation gave a linear......% was the best, which is also in accordance to the fish growth. The ratio of fish food was also calibrated to be 70% due to a food chain in the water and 30% due to a food chain in the sediment. This gave the lowest uncertainty of the model. The simple metal model was working acceptably well for Pb, Cu and Cd...

  3. The predicted effectiveness of noble metal treatment at the Chinshan boiling water reactor

    International Nuclear Information System (INIS)

    Yeh Tsungkuang; Chu Fang; Chang Ching; Huang Chiashen

    2000-01-01

    The technique of noble metal treatment (NMT) available in a form of noble metal cooling (NMC) or noble metal chemical addition (NMCA), was introduced to enhance effectiveness of hydrogen water chemistry. Since it is technically difficult to gain access to an entire primary heat transport circuit (PHTC) of a BWR and monitor variation on electrochemical corrosion potential (ECP), a question whether the NMC technology is indeed effective for lowering the ECP of every location in a BWR is not still well understood at the moment. Then, computer modeling is so far the best tool to help investigate effectiveness of the NMT along PHCT of the BWR. Here was discussed on how the computer model was calibrated by using measured chemistry data obtained from No. 2 unit (BWR) in the Kuosheng Plant. The effect of noble metal treatment coupled with hydrogen water chemistry has been quantitatively molded, on a base of two different sets of ECD enhancement data. It was predicted that No. 1 unit in the Chinshan could be protected by noble metal treatment with lower [H 2 ] FW . In the case of competitive enhancing factors for the ECDs of oxygen reduction, hydrogen peroxide reduction, and hydrogen oxidation reactions, HWC had always to be present for noble metal treatment to be effective for protecting a reactor. Otherwise, according to a model calculation based upon the results from Kim's work, the ECP might instead be increased due to the enhanced reduction reaction rate of oxygen and hydrogen peroxide, especially in the near core regions. (G.K.)

  4. Correlation of Gas Permeability in a Metal-Organic Framework MIL-101(Cr)-Polysulfone Mixed-Matrix Membrane with Free Volume Measurements by Positron Annihilation Lifetime Spectroscopy (PALS).

    Science.gov (United States)

    Jeazet, Harold B Tanh; Koschine, Tönjes; Staudt, Claudia; Raetzke, Klaus; Janiak, Christoph

    2013-10-25

    Hydrothermally stable particles of the metal-organic framework MIL-101(Cr) were incorporated into a polysulfone (PSF) matrix to produce mixed-matrix or composite membranes with excellent dispersion of MIL-101 particles and good adhesion within the polymer matrix. Pure gas (O2, N2, CO2 and CH4) permeation tests showed a significant increase of gas permeabilities of the mixed-matrix membranes without any loss in selectivity. Positron annihilation lifetime spectroscopy (PALS) indicated that the increased gas permeability is due to the free volume in the PSF polymer and the added large free volume inside the MIL-101 particles. The trend of the gas transport properties of the composite membranes could be reproduced by a Maxwell model.

  5. Correlation of Gas Permeability in a Metal-Organic Framework MIL-101(Cr)–Polysulfone Mixed-Matrix Membrane with Free Volume Measurements by Positron Annihilation Lifetime Spectroscopy (PALS)

    Science.gov (United States)

    Jeazet, Harold B. Tanh; Koschine, Tönjes; Staudt, Claudia; Raetzke, Klaus; Janiak, Christoph

    2013-01-01

    Hydrothermally stable particles of the metal-organic framework MIL-101(Cr) were incorporated into a polysulfone (PSF) matrix to produce mixed-matrix or composite membranes with excellent dispersion of MIL-101 particles and good adhesion within the polymer matrix. Pure gas (O2, N2, CO2 and CH4) permeation tests showed a significant increase of gas permeabilities of the mixed-matrix membranes without any loss in selectivity. Positron annihilation lifetime spectroscopy (PALS) indicated that the increased gas permeability is due to the free volume in the PSF polymer and the added large free volume inside the MIL-101 particles. The trend of the gas transport properties of the composite membranes could be reproduced by a Maxwell model. PMID:24957061

  6. Nuclear lifetime measurement

    International Nuclear Information System (INIS)

    Guillaume, Georges

    Three direct techniques of lifetime measurement are emphasized: electronic methods and two methods based on the Doppler effect (the recoil distance methods or RDM, the Doppler shift attenuation methods or DSAM). Said direct methods are concerned with the direct measurement of the radioactive decay constants of nuclear excited states. They allow lifetimes of nucleus bound states whose deexcitations occur by electromagnetic transitions, to be determined. Other methods for measuring lifetimes are also examined: microwave techniques and those involving the blocking effect in crystals (direct methods) and also various indirect methods of obtaining lifetimes (γ resonance scattering, capture reactions, inelastic electron and nucleus scattering, and Coulomb deexcitation) [fr

  7. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    International Nuclear Information System (INIS)

    Pauget, B.; Gimbert, F.; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-01-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO 4 , EDTA, CaCl 2 , NH 4 NO 3 , NaNO 3 , free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r² adj = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r² adj = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: ► New approach to identify chemical methods able to predict metal bioavailability to snails. ► Bioavailability of cadmium, lead and zinc to snails was determined by

  8. Soil parameters are key factors to predict metal bioavailability to snails based on chemical extractant data

    Energy Technology Data Exchange (ETDEWEB)

    Pauget, B.; Gimbert, F., E-mail: frederic.gimbert@univ-fcomte.fr; Scheifler, R.; Coeurdassier, M.; Vaufleury, A. de

    2012-08-01

    Although soil characteristics modulate metal mobility and bioavailability to organisms, they are often ignored in the risk assessment of metal transfer. This paper aims to determine the ability of chemical methods to assess and predict cadmium (Cd), lead (Pb) and zinc (Zn) environmental bioavailability to the land snail Cantareus aspersus. Snails were exposed in the laboratory for 28 days to 17 soils from around a former smelter. The soils were selected for their range of pH, organic matter, clay content, and Cd, Pb and Zn concentrations. The influence of soil properties on environmental availability (estimated using HF-HClO{sub 4}, EDTA, CaCl{sub 2}, NH{sub 4}NO{sub 3}, NaNO{sub 3}, free ion activity and total dissolved metal concentration in soil solution) and on environmental bioavailability (modelled using accumulation kinetics) was identified. Among the seven chemical methods, only the EDTA and the total soil concentration can be used to assess Cd and Pb environmental bioavailability to snails (r Superscript-Two {sub adj} = 0.67 and 0.77, respectively). For Zn, none of the chemical methods were suitable. Taking into account the influence of the soil characteristics (pH and CEC) allows a better prediction of Cd and Pb environmental bioavailability (r Superscript-Two {sub adj} = 0.82 and 0.83, respectively). Even though alone none of the chemical methods tested could assess Zn environmental bioavailability to snails, the addition of pH, iron and aluminium oxides allowed the variation of assimilation fluxes to be predicted. A conceptual and practical method to use soil characteristics for risk assessment is proposed based on these results. We conclude that as yet there is no universal chemical method to predict metal environmental bioavailability to snails, and that the soil factors having the greatest impact depend on the metal considered. - Highlights: Black-Right-Pointing-Pointer New approach to identify chemical methods able to predict metal bioavailability

  9. Annual and long-term prediction of the atmospheric corrosion of metals

    International Nuclear Information System (INIS)

    Morcillo, M.

    1998-01-01

    The atmospheric corrosion of metals is known to be a discontinuous electrochemical process which takes place only when the metallic surface is wet or moistened by different meteorological phenomena (rain, humidity condensation, fog, etc.) The magnitude of atmospheric corrosion would be relatively low if it were not for the presence of certain pollutants in the atmosphere, mainly sulphur dioxide (anthropogenic pollutant) and marine chlorides (natural pollutant). The literature contains different models for predicting the atmospheric metals over short periods (generally one year) and long periods (15, 20 or more years) of atmospheric exposure. In addition to the different meteorological factors (volume of precipitation, days of rain, relative humidity (RH), T, etc.), atmospheric SO 2 deposition rate and atmospheric salinity (Cl - ) appear as independent variables in all of these models. (Author)

  10. Predicting of bead undercut defects in high-speed gas metal arc welding (GMAW)

    Institute of Scientific and Technical Information of China (English)

    Wen-jing XU; Chuan-song WU; De-gang ZOU

    2008-01-01

    In the gas metal arc welding (GMAW) process, when the welding speed reaches a certain threshold, there will be an onset of weld bead undercut defects which limit the further increase of the welding speed. Establishing a mathematical model for high-speed GMAW to predict the tendency of bead undercuts is of great significance to pre-vent such defects. Under the action of various forces, the transferred metal from filler wire to the weld pool, and the geometry and dimension of the pool itself decide if the bead undercut occurs or not. The previous model simpli-fied the pool shape too much. In this paper, based on the actual weld pool geometry and dimension calculated from a numerical model, a hydrostatic model for liquid metal surface is used to study the onset of bead undercut defects in the high-speed welding process and the effects of dif-ferent welding parameters on the bead undercut tendency.

  11. Potential ecological risk assessment and prediction of soil heavy-metal pollution around coal gangue dump

    Science.gov (United States)

    Jiang, X.; Lu, W. X.; Zhao, H. Q.; Yang, Q. C.; Yang, Z. P.

    2014-06-01

    The aim of the present study is to evaluate the potential ecological risk and trend of soil heavy-metal pollution around a coal gangue dump in Jilin Province (Northeast China). The concentrations of Cd, Pb, Cu, Cr and Zn were monitored by inductively coupled plasma mass spectrometry (ICP-MS). The potential ecological risk index method developed by Hakanson (1980) was employed to assess the potential risk of heavy-metal pollution. The potential ecological risk in the order of ER(Cd) > ER(Pb) > ER(Cu) > ER(Cr) > ER(Zn) have been obtained, which showed that Cd was the most important factor leading to risk. Based on the Cd pollution history, the cumulative acceleration and cumulative rate of Cd were estimated, then the fixed number of years exceeding the standard prediction model was established, which was used to predict the pollution trend of Cd under the accelerated accumulation mode and the uniform mode. Pearson correlation analysis and correspondence analysis are employed to identify the sources of heavy metals and the relationship between sampling points and variables. These findings provided some useful insights for making appropriate management strategies to prevent or decrease heavy-metal pollution around a coal gangue dump in the Yangcaogou coal mine and other similar areas elsewhere.

  12. A novel approach for predicting the uptake and toxicity of metallic and metalloid ions

    Science.gov (United States)

    Wang, Peng

    2011-01-01

    Electrostatic nature of plant plasma membrane (PM) plays significant roles in the ion uptake and toxicity. Electrical potential at the PM exterior surface (ψ0o) influences ion distribution at the PM exterior surface, and the depolarization of ψ0o negativity increases the electrical driving force for cation transport, but decreases the driving force for anion transport across the PMs. Assessing environmental risks of toxic ions has been a difficult task because the ion concentration (activity) in medium is not directly corrected to its potential effects. Medium characteristics like the content of major cations have important influences on the bioavailability and toxicity of ions in natural waters and soils. Models such as the Free Ion Activity Model (FIAM) and the Biotic Ligand Model (BLM), as usually employed, neglect the ψ0o and hence often lead to false conclusions about interaction mechanisms between toxic ions and major cations for biology. The neglect of ψ0o is not inconsistent with its importance, and possibly reflects the difficulty in the measurement of ψ0o. Based on the dual effects of the ψ0o, electrostatic models were developed to better predict the uptake and toxicity of metallic and metalloid ions. These results suggest that the electrostatic models provides a more robust mechanistic framework to assess metal(loid) ecotoxicity and predict critical metal(loid) concentrations linked to a biological effect, indicating its potential utility in risk assessment of metal(loid)s in water and terrestrial ecosystems. PMID:21386661

  13. Lifetime of Mechanical Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Leland, K.

    1999-07-01

    The gas plant at Kaarstoe was built as part of the Statpipe gas transport system and went on stream in 1985. In 1993 another line was routed from the Sleipner field to carry condensate, and the plant was extended accordingly. Today heavy additional supply- and export lines are under construction, and the plant is extended more than ever. The main role of the factory is to separate the raw gas into commercial products and to pump or ship it to the markets. The site covers a large number of well-known mechanical equipment. This presentation deals with piping, mechanical and structural disciplines. The lifetime of mechanical equipment is often difficult to predict as it depends on many factors, and the subject is complex. Mechanical equipment has been kept in-house, which provides detailed knowledge of the stages from a new to a 14 years old plant. The production regularity has always been very high, as required. The standard of the equipment is well kept, support systems are efficient, and human improvisation is extremely valuable.

  14. On the temperatures, colours, and ages of metal-poor stars predicted by stellar models

    International Nuclear Information System (INIS)

    Van den Berg, D A

    2008-01-01

    Most (but not all) of the investigations that have derived the effective temperatures of metal-poor, solar-neighbourhood field stars, from analyses of their spectra or from the infrared flux method, favour a T eff scale that is ∼100-120 K cooler than that given by stellar evolutionary models. This seems to be at odds with photometric results, given that the application of current colour-T eff relations to the observed subdwarf colours suggests a preference for hotter temperatures. Moreover, the predicted temperatures for main-sequence stars at the lowest metallicities ([Fe/H] eff for them unless some fundamental modification is made to the adopted physics. No such problems are found if the temperatures of metal-poor field stars are ∼100-120 K warmer than most determinations. In this case, stellar models would appear to provide consistent interpretations of both field and globular cluster (GC) stars of low metallicity. However, this would imply, e.g. that M 92 has an [Fe/H] value of approximately - 2.2, which is obtained from analyses of Fe I lines, instead of approximately equal to - 2.4, as derived from Fe II lines (and favoured by studies of three-dimensional model atmospheres). Finally, the age of the local, Population II subgiant HD 140283 (and GCs having similar metal abundances) is estimated to be ∼13 Gyr, if diffusive processes are taken into account.

  15. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Alford, T. L., E-mail: TA@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Khorasani, Arash Elhami [ON Semiconductor Corp., Phoenix, Arizona 85005 (United States); Theodore, N. D. [CHD-Fab, Freescale Semiconductor Inc., Tempe, Arizona 85224 (United States); Dhar, A. [Intel Corp., 2501 NW 229th Ave, Hillsboro, Oregon 97124 (United States)

    2015-11-28

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO{sub 2}/Au/TiO{sub 2} and TiO{sub 2}/Ag/TiO{sub 2}, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.

  16. Hadronization, spin and lifetimes

    International Nuclear Information System (INIS)

    Grossman, Yuval; Nachshon, Itay

    2008-01-01

    Measurements of lifetimes can be done in two ways. For very short lived particles, the width can be measured. For long lived ones, the lifetime can be directly measured, for example, using a displaced vertex. Practically, the lifetime cannot be extracted for particles with intermediate lifetimes. We show that for such cases information about the lifetime can be extracted for heavy colored particles that can be produced with known polarization. For example, a t-like particle with intermediate lifetime hadronizes into a superposition of the lowest two hadronic states, T* and T (the equivalent of B* and B). Depolarization effects are governed by time scales that are much longer than the hadronization time scale, Λ QCD -1 . After a time of order 1/Δm, with Δm≡m(T*)-m(T), half of the initial polarization is lost. The polarization is totally lost after a time of order 1/Γ γ , with Γ γ = Γ(T* → Tγ). Thus, by comparing the initial and final polarization, we get information on the particle's lifetime.

  17. A simple criterion to predict the glass forming ability of metallic alloys

    International Nuclear Information System (INIS)

    Falcao de Oliveira, Marcelo

    2012-01-01

    A new and simple criterion with which to quantitatively predict the glass forming ability (GFA) of metallic alloys is proposed. It was found that the critical cooling rate for glass formation (R C ) correlates well with a proper combination of two factors, the minimum topological instability (λ min ) and the Δh parameter, which depends on the average work function difference (Δφ) and the average electron density difference (Δn ws 1/3 ) among the constituent elements of the alloy. A correlation coefficient (R 2 ) of 0.76 was found between R c and the new criterion for 68 alloys in 30 different metallic systems. The new criterion and the Uhlmann's approach were used to estimate the critical amorphous thickness (Z C ) of alloys in the Cu-Zr system. The new criterion underestimated R C in the Cu-Zr system, producing predicted Z C values larger than those observed experimentally. However, when considering a scale factor, a remarkable similarity was observed between the predicted and the experimental behavior of the GFA in the binary Cu-Zr. When using the same scale factor and performing the calculation for the ternary Zr-Cu-Al, good agreement was found between the predicted and the actual best GFA region, as well as between the expected and the observed critical amorphous thickness.

  18. Effect of continuum damage mechanics on spring back prediction in metal forming processes

    International Nuclear Information System (INIS)

    Nayebi, Ali; Shahabi, Mehdi

    2017-01-01

    The influence of considering the variations in material properties was investigated through continuum damage mechanics according to the Lemaitre isotropic unified damage law to predict the bending force and spring back in V-bending sheet metal forming processes, with emphasis on Finite element (FE) simulation considerations. The material constants of the damage model were calibrated through a uniaxial tensile test with an appropriate and convenient repeating strategy. Holloman’s isotropic and Ziegler’s linear kinematic hardening laws were employed to describe the behavior of a hardening material. To specify the ideal FE conditions for simulating spring back, the effect of the various numerical considerations during FE simulation was investigated and compared with the experimental outcome. Results indicate that considering continuum damage mechanics decreased the predicted bending force and improved the accuracy of spring back prediction.

  19. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting

    Directory of Open Access Journals (Sweden)

    JuneHyuck Lee

    2018-05-01

    Full Text Available The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT, artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry.

  20. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting

    Science.gov (United States)

    Lee, JuneHyuck; Noh, Sang Do; Kim, Hyun-Jung; Kang, Yong-Shin

    2018-01-01

    The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS) perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT), artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry. PMID:29734699

  1. Implementation of Cyber-Physical Production Systems for Quality Prediction and Operation Control in Metal Casting.

    Science.gov (United States)

    Lee, JuneHyuck; Noh, Sang Do; Kim, Hyun-Jung; Kang, Yong-Shin

    2018-05-04

    The prediction of internal defects of metal casting immediately after the casting process saves unnecessary time and money by reducing the amount of inputs into the next stage, such as the machining process, and enables flexible scheduling. Cyber-physical production systems (CPPS) perfectly fulfill the aforementioned requirements. This study deals with the implementation of CPPS in a real factory to predict the quality of metal casting and operation control. First, a CPPS architecture framework for quality prediction and operation control in metal-casting production was designed. The framework describes collaboration among internet of things (IoT), artificial intelligence, simulations, manufacturing execution systems, and advanced planning and scheduling systems. Subsequently, the implementation of the CPPS in actual plants is described. Temperature is a major factor that affects casting quality, and thus, temperature sensors and IoT communication devices were attached to casting machines. The well-known NoSQL database, HBase and the high-speed processing/analysis tool, Spark, are used for IoT repository and data pre-processing, respectively. Many machine learning algorithms such as decision tree, random forest, artificial neural network, and support vector machine were used for quality prediction and compared with R software. Finally, the operation of the entire system is demonstrated through a CPPS dashboard. In an era in which most CPPS-related studies are conducted on high-level abstract models, this study describes more specific architectural frameworks, use cases, usable software, and analytical methodologies. In addition, this study verifies the usefulness of CPPS by estimating quantitative effects. This is expected to contribute to the proliferation of CPPS in the industry.

  2. Development of Universal Methodology of Specimen Free Nondestructive Inspection (Control) of Mechanical Properties of NPP Equipment Metal in all Stages of Lifetime

    International Nuclear Information System (INIS)

    Bakirov, M.; Chubarov, S.; Frolov, I.; Kiselev, I.; Gastrock, J.; Dripke, M.

    2011-01-01

    indications on tensile yield stress elevation due to hardening and also loss in ductility. The work-hardening index may be easily obtained, giving information on the ability of the material (e.g. pressure vessel steel and weld) to deform plastically without brittle fracture. Taking into account the experience of the Center of Material Science and Lifetime Management Ltd. (CMSLM Ltd.) in the use of methods of hardness testing for the inspection of the equipment of NPP of Russian manufacture in Russia, Germany, Czech, Slovakia, Bulgaria, and also similar successful works in this direction in USA (Oakridge), to Czech (NRI Rez) and other countries, it can be seen that the most promising direction in the field of specimen-free inspection of mechanical properties by use of hardness and hardness-related characteristics is use of the kinetic indentation method (KIM, ABIT). This method is based on recording the process of elastoplastic deformation caused by the indentation of a ball indenter. This method allows one to obtain, besides hardness values, tensile properties, elongation, work hardening coefficient, true-stress/true strain diagrammes which normally required the destructive testing of small specimens. However, till now there is no universal method of interpreting the information obtained, although it is generally known that irradiation causes a loss in ductility and increase in hardness and lowering of the work-hardening coefficient. Thus, it is necessary to develop a uniform methodology of using KIM, ABIT with reference to the inspection of materials which will allow unifying the inspection of materials of various classes of the equipment of NPP over all stages of life cycle. With the purpose of introduction of such a methodology it is necessary to develop and realize the program in the frames of IAEA with the above name. (author)

  3. Tool-life prediction under multi-cycle loading during metal forming: a feasibility study

    Directory of Open Access Journals (Sweden)

    Hu Yiran

    2015-01-01

    Full Text Available In the present research, the friction and wear behaviour of a hard coating were studied by using ball-on-disc tests to simulate the wear process of the coated tools for sheet metal forming process. The evolution of the friction coefficient followed a typical dual-plateau pattern, i.e. at the initial stage of sliding, the friction coefficient was relatively low, followed by a sharp increase due to the breakdown of the coatings after a certain number of cyclic dynamic loadings. This phenomenon was caused by the interactive response between the friction and wear from a coating tribo-system, which is often neglected by metal forming researchers, and constant friction coefficient values are normally used in the finite element (FE simulations to represent the complex tribological nature at the contact interfaces. Meanwhile, most of the current FE simulations consider single-cycle loading processes, whereas many metal-forming operations are conducted in a form of multi-cycle loading. Therefore, a novel friction/wear interactive friction model was developed to, simultaneously, characterise the evolutions of friction coefficient and the remaining thickness of the coating layer, to enable the wear life of coated tooling to be predicted. The friction model was then implemented into the FE simulation of a sheet metal forming process for feasibility study.

  4. Prediction Of Formability In Sheet Metal Forming Processes Using A Local Damage Model

    International Nuclear Information System (INIS)

    Teixeira, P.; Santos, Abel; Cesar Sa, J.; Andrade Pires, F.; Barata da Rocha, A.

    2007-01-01

    The formability in sheet metal forming processes is mainly conditioned by ductile fracture resulting from geometric instabilities due to necking and strain localization. The macroscopic collapse associated with ductile failure is a result of internal degradation described throughout metallographic observations by the nucleation, growth and coalescence of voids and micro-cracks. Damage influences and is influenced by plastic deformation and therefore these two dissipative phenomena should be coupled at the constitutive level. In this contribution, Lemaitre's ductile damage model is coupled with Hill's orthotropic plasticity criterion. The coupling between damaging and material behavior is accounted for within the framework of Continuum Damage Mechanics (CDM). The resulting constitutive equations are implemented in the Abaqus/Explicit code, for the prediction of fracture onset in sheet metal forming processes. The damage evolution law takes into account the important effect of micro-crack closure, which dramatically decreases the rate of damage growth under compressive paths

  5. Systematic prediction of high-pressure melting curves of transition metals

    International Nuclear Information System (INIS)

    Hieu, Ho Khac

    2014-01-01

    The pressure effects on melting temperatures of transition metals have been studied based on the combination of the modified Lindemann criterion with statistical moment method in quantum statistical mechanics. Numerical calculations have been performed for five transition metals including Cu, Pd, Pt, Ni, and Mn up to pressure 100 GPa. Our results are in good and reasonable agreements with available experimental data. This approach gives us a relatively simple method for qualitatively calculating high-pressure melting temperature. Moreover, it can be used to verify future experimental and theoretical works. This research proposes the potential of the combination of statistical moment method and the modified Lindemann criterion on predicting high-pressure melting of materials.

  6. A new constitutive model for prediction of springback in sheet metal forming

    International Nuclear Information System (INIS)

    Appiah, E.; Jain, M.

    2004-01-01

    With advances in computer capabilities, cost of sheet metal forming has being reducing mainly due to the reduction of trial and error approaches. At the moment, a complete process can be simulated on computer and appropriate forming conditions optimized before actual industrial forming process is carried out. While formability predictions have improved, the problem of springback exhibited by most metal, including aluminum alloy AA6111-T4, after forming persist and often leads to significant part fit-up problems during assembly. There are a number of factors that affect springback and perhaps the most significant one is constitutive equation. In this paper springback predicted by six advanced kinematic models are evaluated. In addition an improved constitutive kinematic model is presented. It is shown that by adding stress correction term (SCT) to Armstrong-Frederick model a relatively simple and yet accurate stress prediction could be obtained. The SCT was developed with the assumption that the yield surface remains convex, yield center depends on translation, size and shape variations of the yield surface. The model is implemented in a commercial finite element code (ABAQUS/Standard) via its user material interface (UMAT). Numerical simulations of U-bending were performed using automotive aluminum sheet material (AA6111-T4). It was noted that springback has inverse relationship with residual stress

  7. Numerical prediction of the cyclic behaviour of metallic polycrystals and comparison with experimental data

    International Nuclear Information System (INIS)

    Sauzay, M.; Ferrie, E.; Steckmeyer, A.

    2010-01-01

    Grain size seems to have only a minor influence on the cyclic strain strain curves (CSSCs) of metallic polycrystals of medium to high stacking fault energy (SFE). Many authors therefore tried to deduce the macroscopic CSSCs curves from the single crystals ones. Either crystals oriented for single slip or multiple slip were considered. In addition, a scale transition law should be used (from the grain scale to the macroscopic scale). The Sachs rule (homogeneous stress, single slip) or the Taylor one (homogeneous plastic strain, multiple slip) were usually used. But the predicted macroscopic CSSCs do not generally agree with the experimental data for metals and alloys, presenting various SFE values. In order to avoid the choice of a particular scale transition rule, many finite element (FE) computations are carried out using meshes of polycrystals including more than one hundred grains without texture. This allows the study of the influence of the crystalline constitutive laws on the macroscopic CSSCs. Activation of a secondary slip system in grains oriented for single slip is either allowed or hindered (slip planarity), which affects strongly the macroscopic CSSCs. The more planar the slip, the higher the predicted macroscopic stress amplitudes. If grains oriented for single slip obey slip planarity and two crystalline CSSCs are used (one for single slip grains and one for multiple slip grains), then the predicted macroscopic CSSCs agree well with experimental data provided the SFE is not too low (austenitic steel 316L, copper, nickel, aluminium). (authors)

  8. Biodynamic modelling and the prediction of accumulated trace metal concentrations in the polychaete Arenicola marina

    International Nuclear Information System (INIS)

    Casado-Martinez, M. Carmen; Smith, Brian D.; DelValls, T. Angel; Luoma, Samuel N.; Rainbow, Philip S.

    2009-01-01

    The use of biodynamic models to understand metal uptake directly from sediments by deposit-feeding organisms still represents a special challenge. In this study, accumulated concentrations of Cd, Zn and Ag predicted by biodynamic modelling in the lugworm Arenicola marina have been compared to measured concentrations in field populations in several UK estuaries. The biodynamic model predicted accumulated field Cd concentrations remarkably accurately, and predicted bioaccumulated Ag concentrations were in the range of those measured in lugworms collected from the field. For Zn the model showed less but still good comparability, accurately predicting Zn bioaccumulation in A. marina at high sediment concentrations but underestimating accumulated Zn in the worms from sites with low and intermediate levels of Zn sediment contamination. Therefore, it appears that the physiological parameters experimentally derived for A. marina are applicable to the conditions encountered in these environments and that the assumptions made in the model are plausible. - Biodynamic modelling predicts accumulated field concentrations of Ag, Cd and Zn in the deposit-feeding polychaete Arenicola marina.

  9. Predicting catalyst-support interactions between metal nanoparticles and amorphous silica supports

    Science.gov (United States)

    Ewing, Christopher S.; Veser, Götz; McCarthy, Joseph J.; Lambrecht, Daniel S.; Johnson, J. Karl

    2016-10-01

    Metal-support interactions significantly affect the stability and activity of supported catalytic nanoparticles (NPs), yet there is no simple and reliable method for estimating NP-support interactions, especially for amorphous supports. We present an approach for rapid prediction of catalyst-support interactions between Pt NPs and amorphous silica supports for NPs of various sizes and shapes. We use density functional theory calculations of 13 atom Pt clusters on model amorphous silica supports to determine linear correlations relating catalyst properties to NP-support interactions. We show that these correlations can be combined with fast discrete element method simulations to predict adhesion energy and NP net charge for NPs of larger sizes and different shapes. Furthermore, we demonstrate that this approach can be successfully transferred to Pd, Au, Ni, and Fe NPs. This approach can be used to quickly screen stability and net charge transfer and leads to a better fundamental understanding of catalyst-support interactions.

  10. Quantum lifetime in electron storage rings

    International Nuclear Information System (INIS)

    Chao, A.W.

    1977-02-01

    One of the mechanisms which contribute to beam lifetime in electron storage rings is the quantum emission of energetic photons causing particles to be lost from the rf bucket. This quantum lifetime is among other things important in defining the required aperture in a storage ring. An approximate expression of quantum lifetime, predicted by a one-dimensional model which takes into account only the betatron motion, has been used in most storage ring designs. If the beam is aperture-limited at a position with nonzero dispersion, both the betatron and synchrotron motions have to be included and a two-dimensional model must be used. An exact expression of quantum lifetime for the one-dimensional case and an approximate expression for the two-dimensional case are given

  11. Quantum lifetime in electron storage rings

    International Nuclear Information System (INIS)

    Chao, A.W.

    1977-01-01

    One of the mechanisms which contributes to beam lifetime in electron storage rings is the quantum emission of energetic photons causing particles to be lost from the rf bucket. This quantum lifetime is among other things important in defining the required aperture in a storage ring. An approximate expression of quantum lifetime, predicted by a one-dimensional model which takes into account only the betatron motion, has been used in most storage ring designs. If the beam is aperture-limited at a position with nonzero dispersion, both the betatron and synchrotron motions have to be included, and a two-dimensional model must be used. An exact expression of quantum lifetime for the one-dimensional case and an approximate expression for the two-dimensional case are given

  12. Positron lifetime in vanadium oxide bronzes

    International Nuclear Information System (INIS)

    Dryzek, J.; Dryzek, E.

    2003-01-01

    The positron lifetime (PL) and Doppler broadening (DB) of annihilation line measurements have been performed in vanadium oxide bronzes M x V 2 O 5 . The dependence of these annihilation characteristics on the kind and concentration of the metal M donor has been observed. In the PL spectrum only one lifetime component has been detected in all studied bronzes. The results indicate the positron localization in the structural tunnels present in the crystalline lattice of the vanadium oxide bronzes. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Prediction of heat generation in rubber or rubber-metal springs

    Directory of Open Access Journals (Sweden)

    Banić Milan S.

    2012-01-01

    Full Text Available The temperature of rubber or rubber-metal springs increases under cyclic loading, due to hysteresis losses and low rubber thermal conductivity. Hysteresis losses correspond to energy dissipation from the rubber, which is primarily converted into heat. This well-known phenomenon, called heat build-up, is the primary reason for rubber aging. Increase in temperature within the rubber compound leads to degradation of its physical and chemical properties, increase in stiffness and loss of damping capability. This paper presents a novel procedure of heat generation prediction in rubber or rubber-metal springs. The procedure encompasses the prediction of hysteresis loss, i. e. dissipated energy within the rubber, by finite element analysis and application of a modern visco-plastic rubber constitutive model. The obtained dissipated energy was used as an input for transient thermal analysis. Verification of the proposed procedure was performed by comparison of simulation results with experimentally obtained data during the dynamic loading of the rubber specimen. The proposed procedure is highly computationally efficient and it enables time integration, which can be problematic in coupled mechanical thermal analysis. [Projekat Ministarstva nauke Republike Srbije, br. TR35005: Research and Development of New Generation of Wind Turbines of High Energy Efficiency

  14. The prediction of creep damage in Type 347 weld metal: part II creep fatigue tests

    International Nuclear Information System (INIS)

    Spindler, M.W.

    2005-01-01

    Calculations of creep damage under conditions of strain control are often carried out using either a time fraction approach or a ductility exhaustion approach. In part I of this paper the rupture strength and creep ductility data for a Type 347 weld metal were fitted to provide the material properties that are used to calculate creep damage. Part II of this paper examines whether the time fraction approach or the ductility exhaustion approach gives the better predictions of creep damage in creep-fatigue tests on the same Type 347 weld metal. In addition, a new creep damage model, which was developed by removing some of the simplifying assumptions that are made in the ductility exhaustion approach, was used. This new creep damage model is a function of the strain rate, stress and temperature and was derived from creep and constant strain rate test data using a reverse modelling technique (see part I of this paper). It is shown that the new creep damage model gives better predictions of creep damage in the creep-fatigue tests than the time fraction and the ductility exhaustion approaches

  15. Precision lifetime measurements

    International Nuclear Information System (INIS)

    Tanner, C.E.

    1994-01-01

    Precision measurements of atomic lifetimes provide important information necessary for testing atomic theory. The authors employ resonant laser excitation of a fast atomic beam to measure excited state lifetimes by observing the decay-in-flight of the emitted fluorescence. A similar technique was used by Gaupp, et al., who reported measurements with precisions of less than 0.2%. Their program includes lifetime measurements of the low lying p states in alkali and alkali like systems. Motivation for this work comes from a need to test the atomic many-body-perturbation theory (MBPT) that is necessary for interpretation of parity nonconservation experiments in atomic cesium. The authors have measured the cesium 6p 2 P 1/2 and 6p 2 P 3/2 state lifetimes to be 34.934±0.094 ns and 30.499±0.070 ns respectively. With minor changes to the apparatus, they have extended their measurements to include the lithium 2p 2 P 1/2 and 2p 2 P 3/2 states

  16. Investigating the binding properties of porous drug delivery systems using nuclear sensors (radiotracers) and positron annihilation lifetime spectroscopy--predicting conditions for optimum performance.

    Science.gov (United States)

    Mume, Eskender; Lynch, Daniel E; Uedono, Akira; Smith, Suzanne V

    2011-06-21

    Understanding how the size, charge and number of available pores in porous material influences the uptake and release properties is important for optimising their design and ultimately their application. Unfortunately there are no standard methods for screening porous materials in solution and therefore formulations must be developed for each encapsulated agent. This study investigates the potential of a library of radiotracers (nuclear sensors) for assessing the binding properties of hollow silica shell materials. Uptake and release of Cu(2+) and Co(2+) and their respective complexes with polyazacarboxylate macrocycles (dota and teta) and a series of hexa aza cages (diamsar, sarar and bis-(p-aminobenzyl)-diamsar) from the hollow silica shells was monitored using their radioisotopic analogues. Coordination chemistry of the metal (M) species, subtle alterations in the molecular architecture of ligands (Ligand) and their resultant complexes (M-Ligand) were found to significantly influence their uptake over pH 3 to 9 at room temperature. Positively charged species were selectively and rapidly (within 10 min) absorbed at pH 7 to 9. Negatively charged species were preferentially absorbed at low pH (3 to 5). Rates of release varied for each nuclear sensor, and time to establish equilibrium varied from minutes to days. The subtle changes in design of the nuclear sensors proved to be a valuable tool for determining the binding properties of porous materials. The data support the development of a library of nuclear sensors for screening porous materials for use in optimising the design of porous materials and the potential of nuclear sensors for high through-put screening of materials.

  17. A study on the development of advanced models to predict the critical heat flux for water and liquid metals

    International Nuclear Information System (INIS)

    Lee, Yong Bum

    1994-02-01

    The critical heat flux (CHF) phenomenon in the two-phase convective flows has been an important issue in the fields of design and safety analysis of light water reactor (LWR) as well as sodium cooled liquid metal fast breeder reactor (LMFBR). Especially in the LWR application many physical aspects of the CHF phenomenon are understood and reliable correlations and mechanistic models to predict the CHF condition have been proposed. However, there are few correlations and models which are applicable to liquid metals. Compared with water, liquid metals show a divergent picture for boiling pattern. Therefore, the CHF conditions obtained from investigations with water cannot be applied to liquid metals. In this work a mechanistic model to predict the CHF of water and a correlation for liquid metals are developed. First, a mechanistic model to predict the CHF in flow boiling at low quality was developed based on the liquid sublayer dryout mechanism. In this approach the CHF is assumed to occur when a vapor blanket isolates the liquid sublayer from bulk liquid and then the liquid entering the sublayer falls short of balancing the rate of sublayer dryout by vaporization. Therefore, the vapor blanket velocity is the key parameter. In this work the vapor blanket velocity is theoretically determined based on mass, energy, and momentum balance and finally the mechanistic model to predict the CHF in flow boiling at low quality is developed. The accuracy of the present model is evaluated by comparing model predictions with the experimental data and tabular data of look-up tables. The predictions of the present model agree well with extensive CHF data. In the latter part a correlation to predict the CHF for liquid metals is developed based on the flow excursion mechanism. By using Baroczy two-phase frictional pressure drop correlation and Ledinegg instability criterion, the relationship between the CHF of liquid metals and the principal parameters is derived and finally the

  18. A quasi-stationary numerical model of atomized metal droplets, II: Prediction and assessment

    DEFF Research Database (Denmark)

    Pryds, Nini H.; Hattel, Jesper Henri; Thorborg, Jesper

    1999-01-01

    been illustrated.A comparison between the numerical model and the experimental results shows an excellent agreement and demonstrates the validity of the present model, e.g. the calculated gas temperature which has an important influence on the droplet solidification behaviour as well as the calculated......A new model which extends previous studies and includes the interaction between enveloping gas and an array of droplets has been developed and presented in a previous paper. The model incorporates the probability density function of atomized metallic droplets into the heat transfer equations....... The main thrust of the model is that the gas temperature was not predetermined and calculated empirically but calculated numerically based on heat balance consideration. In this paper, the accuracy of the numerical model and the applicability of the model as a predictive tool have been investigated...

  19. Nonequilibrium Molecular Simulations of New Ionic Lubricants at Metallic Surfaces: Prediction of the Friction.

    Science.gov (United States)

    Mendonça, Ana C F; Pádua, Agílio A H; Malfreyt, Patrice

    2013-03-12

    We report nonequilibrium molecular dynamics of ionic liquids interacting with metallic surfaces. A specific set of interaction parameters for ionic liquids composed of alkylammonium cations and alkylsulfonate anions with an iron surface, which has been previously developed (J. Chem. Theory Comput.2012, 8, 3348) is used here. We develop a procedure for a quantitative prediction of the friction coefficient at different loads and shear rates. The simulated friction coefficient agrees very well with the available experimental ones. The dependence of friction on the load, shear velocity, surface topology, and length of alkyl side chains in the ionic liquid is also investigated. The changes in the frictional forces are explained in terms of the specific arrangements and orientations of groups forming the ionic liquid at the vicinity of the surface.

  20. Comparison of various tool wear prediction methods during end milling of metal matrix composite

    Science.gov (United States)

    Wiciak, Martyna; Twardowski, Paweł; Wojciechowski, Szymon

    2018-02-01

    In this paper, the problem of tool wear prediction during milling of hard-to-cut metal matrix composite Duralcan™ was presented. The conducted research involved the measurements of acceleration of vibrations during milling with constant cutting conditions, and evaluation of the flank wear. Subsequently, the analysis of vibrations in time and frequency domain, as well as the correlation of the obtained measures with the tool wear values were conducted. The validation of tool wear diagnosis in relation to selected diagnostic measures was carried out with the use of one variable and two variables regression models, as well as with the application of artificial neural networks (ANN). The comparative analysis of the obtained results enable.

  1. Prediction of the Effects of Radiation FOr Reactor pressure vessel and in-core Materials using multi-scale modeling - 60 years foreseen plant lifetime (PERFORM-60 project)

    International Nuclear Information System (INIS)

    Al Mazouzi, A.; Bugat, S.; Leclercq, S.; Massoud, J.-P.; Moinereau, D.; Lidbury, D.; Van Dyck, S.; Marini, B.; Alamo, Ana

    2010-01-01

    The PERFECT project of the EURATOM framework program (FP6) is a first step through the development of a simulation platform that contains several advanced numerical tools aiming at the prediction of irradiation damage in both the reactor pressure vessel (RPV) and its internals using state-of-the-art knowledge. These tools allow simulation of irradiation effects on the microstructure and the constitutive behavior of the RPV low alloy steels, as well as their fracture mechanics properties. For the reactor internals, the first partial models were established, describing radiation damage to the microstructure and providing a first description of the stress corrosion behaviour of austenitic steels in primary environment, without physical linking of the radiation and corrosion effects. Thus, relying on the existing PERFECT Roadmap, the FP7 Collaborative Project PERFORM 60 has mainly for objective to develop similar tools that would allow the simulation of the combined effects of irradiation and corrosion on internals, in addition to a further improvement of the existing ones on RPV made of bainitic steels. From the managerial view point, PERFORM 60 is based on two technical sub-projects, namely (i) RPV and (ii) Internals. In addition, a Users' Group and a training scheme have been adopted in order to allow representatives of constructors, utilities, research organizations... from Europe, USA and Japan to participate actively in the process of appraising the limits and potentialities of the developed tools as well as their validation against qualified experimental data

  2. Predicting heavy metal concentrations in soils and plants using field spectrophotometry

    Science.gov (United States)

    Muradyan, V.; Tepanosyan, G.; Asmaryan, Sh.; Sahakyan, L.; Saghatelyan, A.; Warner, T. A.

    2017-09-01

    Aim of this study is to predict heavy metal (HM) concentrations in soils and plants using field remote sensing methods. The studied sites were an industrial town of Kajaran and city of Yerevan. The research also included sampling of soils and leaves of two tree species exposed to different pollution levels and determination of contents of HM in lab conditions. The obtained spectral values were then collated with contents of HM in Kajaran soils and the tree leaves sampled in Yerevan, and statistical analysis was done. Consequently, Zn and Pb have a negative correlation coefficient (p regression models and artificial neural network (ANN) for HM prediction were developed. Good results were obtained for the best stress sensitive spectral band ANN (R2 0.9, RPD 2.0), Simple Linear Regression (SLR) and Partial Least Squares Regression (PLSR) (R2 0.7, RPD 1.4) models. Multiple Linear Regression (MLR) model was not applicable to predict Pb and Zn concentrations in soils in this research. Almost all full spectrum PLS models provide good calibration and validation results (RPD>1.4). Full spectrum ANN models are characterized by excellent calibration R2, rRMSE and RPD (0.9; 0.1 and >2.5 respectively). For prediction of Pb and Ni contents in plants SLR and PLS models were used. The latter provide almost the same results. Our findings indicate that it is possible to make coarse direct estimation of HM content in soils and plants using rapid and economic reflectance spectroscopy.

  3. Inelastic behavior of a dissimilar-metal-welded pipe transition joint: comparison of experimental measurements and analytical prediction

    International Nuclear Information System (INIS)

    Yang, T.M.; Dalcher, A.W.

    1979-06-01

    The subject study involved the prediction and observed behavior of a dissimilar metal pipe joint made from 2 1/4 Cr-1Mo steel welded to Type 316 austenitic stainless steel using a nickel-base filler metal, ERNiCr-3. A two-dimensional axi-symmetric finite element model was employed in the analysis, with certain assumptions made relative to the initial stress state of the joint. Internal pressure and thermal loadings which simulated the test conditions experienced by the joint, were used as inputs. Uni-axial stress-strain relationships and creep equations were applied to the multi-axial stress state through the concept of effective stress and equivalent strain. The analysis indicated that the loading history during the preparatory period (before acutal service) has a significant effect on the behavior of the transition joint in its early service life. The magnitudes of the stresses created at the vicinity of the dissimilar metal interfaces, mainly due to the differences in thermal expansions of the metals, are sufficient to yield the metals, and fast thermal down transients during service will induce more yielding of the metals before shakedown occurs. Calculated plastic ratchetting and creep responses of the joint metals were compared with ORNL strain measurements of the test joint. Very good agreement was shown to exist between the predictions and measurements

  4. LHCb: Measurement of $b$-hadron lifetimes at LHCb

    CERN Multimedia

    Amhis, Y

    2014-01-01

    Lifetimes are among the most fundamental properties of elementary particles. Precision Measurements of $b$-hadron lifetimes are an important tool to test theoretical models such as HQET. These models allow to predict various observables related to B-mixing. Using data collected during Run 1 at the LHC, LHCb measured the lifetime of B-decays including a $J/\\psi$ in the final state.

  5. PERFORM 60 - Prediction of the effects of radiation for reactor pressure vessel and in-core materials using multi-scale modelling - 60 years foreseen plant lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Leclercq, Sylvain, E-mail: sylvain.leclercq@edf.f [EDF R and D, Materials and Mechanics of Components, Avenue des Renardieres - Ecuelles, 77818 Moret sur Loing Cedex (France); Lidbury, David [SERCO Assurance - Walton House, 404 Faraday Street, Birchwood Park, Warrington, Cheshire WA3 6GA (United Kingdom); Van Dyck, Steven [SCK-CEN, Nuclear Material Science, Boeretang 200, BE, 2400 Mol (Belgium); Moinereau, Dominique [EDF R and D, Materials and Mechanics of Components, Avenue des Renardieres - Ecuelles, 77818 Moret sur Loing Cedex (France); Alamo, Ana [CEA Saclay, DEN/DSOE, 91191 Gif-sur-Yvette (France); Mazouzi, Abdou Al [EDF R and D, Materials and Mechanics of Components, Avenue des Renardieres - Ecuelles, 77818 Moret sur Loing Cedex (France)

    2010-11-01

    In nuclear power plants, materials may undergo degradation due to severe irradiation conditions that may limit their operational life. Utilities that operate these reactors need to quantify the ageing and the potential degradations of some essential structures of the power plant to ensure safe and reliable plant operation. So far, the material databases needed to take account of these degradations in the design and safe operation of installations mainly rely on long-term irradiation programs in test reactors as well as on mechanical or corrosion testing in specialized hot cells. Continuous progress in the physical understanding of the phenomena involved in irradiation damage and continuous progress in computer sciences have now made possible the development of multi-scale numerical tools able to simulate the effects of irradiation on materials microstructure. A first step towards this goal has been successfully reached through the development of the RPV-2 and Toughness Module numerical tools by the scientific community created around the FP6 PERFECT project. These tools allow to simulate irradiation effects on the constitutive behaviour of the reactor pressure vessel low alloy steel, and also on its failure properties. Relying on the existing PERFECT Roadmap, the 4 years Collaborative Project PERFORM 60 has mainly for objective to develop multi-scale tools aimed at predicting the combined effects of irradiation and corrosion on internals (austenitic stainless steels) and also to improve existing ones on RPV (bainitic steels). PERFORM 60 is based on two technical sub-projects: (i) RPV and (ii) internals. In addition to these technical sub-projects, the Users' Group and Training sub-project shall allow representatives of constructors, utilities, research organizations... from Europe, USA and Japan to receive the information and training to get their own appraisal on limits and potentialities of the developed tools. An important effort will also be made to teach

  6. PERFORM 60 - Prediction of the effects of radiation for reactor pressure vessel and in-core materials using multi-scale modelling - 60 years foreseen plant lifetime

    Science.gov (United States)

    Leclercq, Sylvain; Lidbury, David; Van Dyck, Steven; Moinereau, Dominique; Alamo, Ana; Mazouzi, Abdou Al

    2010-11-01

    In nuclear power plants, materials may undergo degradation due to severe irradiation conditions that may limit their operational life. Utilities that operate these reactors need to quantify the ageing and the potential degradations of some essential structures of the power plant to ensure safe and reliable plant operation. So far, the material databases needed to take account of these degradations in the design and safe operation of installations mainly rely on long-term irradiation programs in test reactors as well as on mechanical or corrosion testing in specialized hot cells. Continuous progress in the physical understanding of the phenomena involved in irradiation damage and continuous progress in computer sciences have now made possible the development of multi-scale numerical tools able to simulate the effects of irradiation on materials microstructure. A first step towards this goal has been successfully reached through the development of the RPV-2 and Toughness Module numerical tools by the scientific community created around the FP6 PERFECT project. These tools allow to simulate irradiation effects on the constitutive behaviour of the reactor pressure vessel low alloy steel, and also on its failure properties. Relying on the existing PERFECT Roadmap, the 4 years Collaborative Project PERFORM 60 has mainly for objective to develop multi-scale tools aimed at predicting the combined effects of irradiation and corrosion on internals (austenitic stainless steels) and also to improve existing ones on RPV (bainitic steels). PERFORM 60 is based on two technical sub-projects: (i) RPV and (ii) internals. In addition to these technical sub-projects, the Users' Group and Training sub-project shall allow representatives of constructors, utilities, research organizations… from Europe, USA and Japan to receive the information and training to get their own appraisal on limits and potentialities of the developed tools. An important effort will also be made to teach young

  7. Metallic ureteral stents in malignant ureteral obstruction: clinical factors predicting stent failure.

    Science.gov (United States)

    Chow, Po-Ming; Hsu, Jui-Shan; Huang, Chao-Yuan; Wang, Shuo-Meng; Lee, Yuan-Ju; Huang, Kuo-How; Yu, Hong-Jheng; Pu, Yeong-Shiau; Liang, Po-Chin

    2014-06-01

    To provide clinical outcomes of the Resonance metallic ureteral stent in patients with malignant ureteral obstruction, as well as clinical factors predicting stent failure. Cancer patients who have received Resonance stents from July 2009 to March 2012 for ureteral obstruction were included for chart review. Stent failure was detected by clinical symptoms, image studies, and renal function tests. Survival analysis for stent duration was used to estimate patency rate and factors predicting stent failure. A total of 117 stents were inserted successfully into 94 ureteral units in 79 patients. There were no major complications. These stents underwent survival analysis and proportional hazard regression. The median duration for the stents was 5.77 months. In multivariate analysis, age (P=0.043), preoperative serum creatinine level (P=0.0174), and cancer type (P=0.0494) were significant factors associated with stent failure. Cancer treatment before and after stent insertion had no effect on stent duration. Resonance stents are effective and safe in relieving malignant ureteral obstructions. Old age and high serum creatinine level are predictors for stent failure. Stents in patients with lower gastrointestinal cancers have longer functional duration.

  8. Quantum system lifetimes and measurement perturbations

    International Nuclear Information System (INIS)

    Najakov, E.

    1977-05-01

    The recently proposed description of quantum system decay in terms of repeated measurement perturbations is modified. The possibility of retarded reductions to a unique quantum state, due to ineffective localization of the decay products at initial time measurements, is simply taken into account. The exponential decay law is verified again. A modified equation giving the observed lifetime in terms of unperturbed quantum decay law, measurement frequency and reduction law is derived. It predicts deviations of the observed lifetime from the umperturbed one, together with a dependence on experimental procedures. The influence of different model unperturbed decay laws and reduction laws on this effect is studied

  9. A statistical method for predicting sound absorbing property of porous metal materials by using quartet structure generation set

    International Nuclear Information System (INIS)

    Guan, Dong; Wu, Jiu Hui; Jing, Li

    2015-01-01

    Highlights: • A random internal morphology and structure generation-growth method, termed as the quartet structure generation set (QSGS), has been utilized based on the stochastic cluster growth theory for numerical generating the various microstructures of porous metal materials. • Effects of different parameters such as thickness and porosity on sound absorption performance of the generated structures are studied by the present method, and the obtained results are validated by an empirical model as well. • This method could be utilized to guide the design and fabrication of the sound-absorption porous metal materials. - Abstract: In this paper, a statistical method for predicting sound absorption properties of porous metal materials is presented. To reflect the stochastic distribution characteristics of the porous metal materials, a random internal morphology and structure generation-growth method, termed as the quartet structure generation set (QSGS), has been utilized based on the stochastic cluster growth theory for numerical generating the various microstructures of porous metal materials. Then by using the transfer-function approach along with the QSGS tool, we investigate the sound absorbing performance of porous metal materials with complex stochastic geometries. The statistical method has been validated by the good agreement among the numerical results for metal rubber from this method and a previous empirical model and the corresponding experimental data. Furthermore, the effects of different parameters such as thickness and porosity on sound absorption performance of the generated structures are studied by the present method, and the obtained results are validated by an empirical model as well. Therefore, the present method is a reliable and robust method for predicting the sound absorption performance of porous metal materials, and could be utilized to guide the design and fabrication of the sound-absorption porous metal materials

  10. Crystal plasticity-based modeling for predicting anisotropic behaviour and formability of metallic materials

    International Nuclear Information System (INIS)

    Pham, Son; Jeong, Youngung; Creuziger, Adam; Iadicola, Mark; Foecke, Tim; Rollett, Anthony

    2016-01-01

    Metallic materials often exhibit anisotropic behaviour under complex load paths because of changes in microstructure, e.g., dislocations and crystallographic texture. In this study, we present the development of constitutive model based on dislocations, point defects and texture in order to predict anisotropic response under complex load paths. In detail, dislocation/solute atom interactions were considered to account for strain aging and static recovery. A hardening matrix based on the interaction of dislocations was built to represent the cross-hardening of different slip systems. Clear differentiation between forward and backward slip directions of dislocations was made to describe back stresses during path changes. In addition, we included dynamic recovery in order to better account for large plastic deformation. The model is validated against experimental data for AA5754-O with path changes, e.g., Figure 1 [1] Another effort is to include microstructure in forming predictions with a minimal increase in computational time. This effort enables comprehensive investigations of the influence of texture-induced anisotropy on formability [2]. Application of these improvements to predict forming limits of various BCC textures, such as γ, ρ, α, η and ϵ fibers and a random (R) texture. These simulations demonstrate that the crystallographic texture has significant (both positive and negative) effects on the forming limit diagrams (Figure 2). For example, the y fiber texture, that is often sought through thermo-mechanical processing due to high r-value, had the highest forming limit in the balanced biaxial strain path but the lowest forming limit under the plane strain path among textures under consideration. (paper)

  11. Lifetime for the Ti X spectrum

    International Nuclear Information System (INIS)

    Singh, Jagjit; Jha, A K S; Mohan, M

    2010-01-01

    We present configuration interaction calculations for the lifetime of 294 fine-structure levels of the Ti X spectrum in the LSJ coupling scheme. The calculations include all the major correlation effects. The relativistic effects are included by adding the mass correction term, Darwin term and spin-orbit interaction term to the non-relativistic Hamiltonian in the Breit-Pauli approximation. The calculated lifetime values are in very close agreement with other available experimental and theoretical results. We have predicted new lifetime results for levels belonging to 3p 2 3d, 3s 2 4p, 3s3p4s, 3s3p4p and various other configurations of Ti X, where no other theoretical and experimental results are available.

  12. Immobilized metal-affinity chromatography protein-recovery screening is predictive of crystallographic structure success

    International Nuclear Information System (INIS)

    Choi, Ryan; Kelley, Angela; Leibly, David; Nakazawa Hewitt, Stephen; Napuli, Alberto; Van Voorhis, Wesley

    2011-01-01

    An overview of the methods used for high-throughput cloning and protein-expression screening of SSGCID hexahistidine recombinant proteins is provided. It is demonstrated that screening for recombinant proteins that are highly recoverable from immobilized metal-affinity chromatography improves the likelihood that a protein will produce a structure. The recombinant expression of soluble proteins in Escherichia coli continues to be a major bottleneck in structural genomics. The establishment of reliable protocols for the performance of small-scale expression and solubility testing is an essential component of structural genomic pipelines. The SSGCID Protein Production Group at the University of Washington (UW-PPG) has developed a high-throughput screening (HTS) protocol for the measurement of protein recovery from immobilized metal-affinity chromatography (IMAC) which predicts successful purification of hexahistidine-tagged proteins. The protocol is based on manual transfer of samples using multichannel pipettors and 96-well plates and does not depend on the use of robotic platforms. This protocol has been applied to evaluate the expression and solubility of more than 4000 proteins expressed in E. coli. The UW-PPG also screens large-scale preparations for recovery from IMAC prior to purification. Analysis of these results show that our low-cost non-automated approach is a reliable method for the HTS demands typical of large structural genomic projects. This paper provides a detailed description of these protocols and statistical analysis of the SSGCID screening results. The results demonstrate that screening for proteins that yield high recovery after IMAC, both after small-scale and large-scale expression, improves the selection of proteins that can be successfully purified and will yield a crystal structure

  13. B Lifetimes and Mixing

    International Nuclear Information System (INIS)

    Evans, Harold G.

    2009-01-01

    The Tevatron experiments, CDF and D0, have produced a wealth of new B-physics results since the start of Run II in 2001. We've observed new B-hadrons, seen new effects, and increased many-fold the precision with which we know the properties of b-quark systems. In these proceedings, we will discuss two of the most fruitful areas in the Tevatron B-physics program: lifetimes and mixing. We'll examine the experimental issues driving these analyses, present a summary of the latest results, and discuss prospects for the future.

  14. Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization.

    Science.gov (United States)

    Wang, Zhongqi; Yang, Bo; Kang, Yonggang; Yang, Yuan

    2016-01-01

    Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method.

  15. Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization

    Directory of Open Access Journals (Sweden)

    Zhongqi Wang

    2016-01-01

    Full Text Available Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method.

  16. Size distribution and concentrations of heavy metals in atmospheric aerosols originating from industrial emissions as predicted by the HYSPLIT model

    Science.gov (United States)

    Chen, Bing; Stein, Ariel F.; Maldonado, Pabla Guerrero; Sanchez de la Campa, Ana M.; Gonzalez-Castanedo, Yolanda; Castell, Nuria; de la Rosa, Jesus D.

    2013-06-01

    This study presents a description of the emission, transport, dispersion, and deposition of heavy metals contained in atmospheric aerosols emitted from a large industrial complex in southern Spain using the HYSPLIT model coupled with high- (MM5) and low-resolution (GDAS) meteorological simulations. The dispersion model was configured to simulate eight size fractions (17 μm) of metals based on direct measurements taken at the industrial emission stacks. Twelve stacks in four plants were studied and the stacks showed considerable differences for both emission fluxes and size ranges of metals. We model the dispersion of six major metals; Cr, Co, Ni, La, Zn, and Mo, which represent 77% of the total mass of the 43 measured elements. The prediction shows that the modeled industrial emissions produce an enrichment of heavy metals by a factor of 2-5 for local receptor sites when compared to urban and rural background areas in Spain. The HYSPLIT predictions based on the meteorological fields from MM5 show reasonable consistence with the temporal evolution of concentrations of Cr, Co, and Ni observed at three sites downwind of the industrial area. The magnitude of concentrations of metals at two receptors was underestimated for both MM5 (by a factor of 2-3) and GDAS (by a factor of 4-5) meteorological runs. The model prediction shows that heavy metal pollution from industrial emissions in this area is dominated by the ultra-fine (<0.66 μm) and fine (<2.5 μm) size fractions.

  17. Lifetime modelling of lead acid batteries

    DEFF Research Database (Denmark)

    Bindner, H.; Cronin, T.; Lundsager, P.

    2005-01-01

    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 lifecycle 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 withspecific 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 yieldedbattery 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...

  18. Functional memory metals

    International Nuclear Information System (INIS)

    Dunne, D.P.

    2000-01-01

    The field of shape memory phenomena in metals and alloys has developed in a sporadic fashion from a scientific curiosity to a vigorously growing niche industry, over a period close to a full working lifetime. Memory metal research and development is replete with scientist and engineer 'true believers', who can finally feel content that their longstanding confidence in the potential of these unusual functional materials has not been misplaced. This paper reviews the current range of medical and non-medical systems and devices which are based on memory metals and attempts to predict trends in applications over the next decade. The market is dominated by Ni Ti alloys which have proved to exhibit the best and most reproducible properties for application in a wide range of medical and non-medical devices

  19. Comparison between numeric and approximate analytic solutions for the prediction of soil metal uptake by roots. Example of cadmium.

    Science.gov (United States)

    Schneider, André; Lin, Zhongbing; Sterckeman, Thibault; Nguyen, Christophe

    2018-04-01

    The dissociation of metal complexes in the soil solution can increase the availability of metals for root uptake. When it is accounted for in models of bioavailability of soil metals, the number of partial differential equations (PDEs) increases and the computation time to numerically solve these equations may be problematic when a large number of simulations are required, for example for sensitivity analyses or when considering root architecture. This work presents analytical solutions for the set of PDEs describing the bioavailability of soil metals including the kinetics of complexation for three scenarios where the metal complex in solution was fully inert, fully labile, or partially labile. The analytical solutions are only valid i) at steady-state when the PDEs become ordinary differential equations, the transient phase being not covered, ii) when diffusion is the major mechanism of transport and therefore, when convection is negligible, iii) when there is no between-root competition. The formulation of the analytical solutions is for cylindrical geometry but the solutions rely on the spread of the depletion profile around the root, which was modelled assuming a planar geometry. The analytical solutions were evaluated by comparison with the corresponding PDEs for cadmium in the case of the French agricultural soils. Provided that convection was much lower than diffusion (Péclet's number<0.02), the cumulative uptakes calculated from the analytic solutions were in very good agreement with those calculated from the PDEs, even in the case of a partially labile complex. The analytic solutions can be used instead of the PDEs to predict root uptake of metals. The analytic solutions were also used to build an indicator of the contribution of a complex to the uptake of the metal by roots, which can be helpful to predict the effect of soluble organic matter on the bioavailability of soil metals. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Masses of charmed particles, decay modes and lifetimes

    International Nuclear Information System (INIS)

    Vajsenberg, A.O.

    1982-01-01

    Basic characteristics of charmed particles obtained up to the middle of 1981 are discussed in the survey. Stated in brief are main predictions of the theory on charmed particles properties. Experimental data on masses, decay modes and lifetimes of D and F mesons as well as charmed baryons are considered. Basic experiments are described. It is pointed out that in the experiments single and pair production events as well as charmed particle decay have been observed. The charmed particles lifetime lies within the limits of 10 -12 - 10 -13 C. The lifetime of D +- mesons is approximately three times longer than the D 0 mesons lifetime. The lifetime of F mesons and Λsub(e) baryons is close to D 0 mesons lifetime [ru

  1. Measurement of the $\\Omega_{c}^{0}$ lifetime

    CERN Document Server

    Adamovich, M.I.; Alexandrov, Yu.A.; Barberis, D.; Beck, M.; Berat, C.; Beusch, W.; Boss, M.; Brons, S.; Bruckner, W.; Buenerd, M.; Buscher, C.; Charignon, F.; Chauvin, J.; Chudakov, E.A.; Dropmann, F.; Engelfried, J.; Faller, F.; Fournier, A.; Gerasimov, S.; Godbersen, M.; Grafstrom, P.; Haller, T.; Heidrich, M.; Hurst, R.B.; Konigsmann, Kay; Konorov, I.; Martens, K.; Martin, P.; Masciocchi, S.; Michaels, R.; Muller, U.; Newsom, C.; Paul, S.; Povh, B.; Ren, Z.; Rey-Campagnolle, M.; Rosner, G.; Rossi, L.; Rudolph, H.; Schmitt, L.; Siebert, H.W.; Simon, A.; Smith, V.J.; Thilmann, O.; Trombini, A.; Vesin, E.; Volkemer, B.; Vorwalter, K.; Walcher, T.; Walder, G.; Werding, R.; Wittmann, E.; Zavertyaev, M.V.

    1995-01-01

    We present the measurement of the lifetime of the Omega_c we have performed using three independent data samples from two different decay modes. Using a Sigma- beam of 340 GeV/c we have obtained clean signals for the Omega_c decaying into Xi- K- pi+ pi+ and Omega- pi+ pi- pi+, avoiding topological cuts normally used in charm analysis. The short but measurable lifetime of the Omega_c is demonstrated by a clear enhancement of the signals at short but finite decay lengths. Using a continuous maximum likelihood method we determined the lifetime to be tau(Omega_c) = 55 +13-11(stat) +18-23(syst) fs. This makes the Omega_c the shortest living weakly decaying particle observed so far. The short value of the lifetime confirms the predicted pattern of the charmed baryon lifetimes and demonstrates that the strong interaction plays a vital role in the lifetimes of charmed hadrons.

  2. Fluorescence lifetime based bioassays

    Science.gov (United States)

    Meyer-Almes, Franz-Josef

    2017-12-01

    Fluorescence lifetime (FLT) is a robust intrinsic property and material constant of fluorescent matter. Measuring this important physical indicator has evolved from a laboratory curiosity to a powerful and established technique for a variety of applications in drug discovery, medical diagnostics and basic biological research. This distinct trend was mainly driven by improved and meanwhile affordable laser and detection instrumentation on the one hand, and the development of suitable FLT probes and biological assays on the other. In this process two essential working approaches emerged. The first one is primarily focused on high throughput applications employing biochemical in vitro assays with no requirement for high spatial resolution. The second even more dynamic trend is the significant expansion of assay methods combining highly time and spatially resolved fluorescence data by fluorescence lifetime imaging. The latter approach is currently pursued to enable not only the investigation of immortal tumor cell lines, but also specific tissues or even organs in living animals. This review tries to give an actual overview about the current status of FLT based bioassays and the wide range of application opportunities in biomedical and life science areas. In addition, future trends of FLT technologies will be discussed.

  3. Extending hydraulic lifetime of iron walls

    International Nuclear Information System (INIS)

    Mackenzie, P.D.; Sivavec, T.M.; Horney, D.P.

    1997-01-01

    Iron walls for control of groundwaters contaminated with chlorinated solvents and reducible metals are becoming much more widely used and field studies of this technology have proven successful to date. However, there is still much uncertainty in predicting long-term performance. This work focuses on two factors affecting the lifetime of the iron media: plugging at the treatment zone entrance and precipitation in the bulk iron media. Plugging at the system entrance is due principally to dissolved oxygen in the incoming water and is an issue in aerobic aquifers or in ex-situ canister tests. In an in-situ treatment system, plugging would result in a dramatic reduction in flow through the iron zone. Designs to minimize plugging in field applications include use of larger iron particles and admixing sand of comparable size with the iron particles. Mineral precipitation in the bulk iron media can lead to porosity losses in the media, again reducing flow through the treatment zone. Decreases in reactivity of the iron media may also occur. The nature of the mineral precipitation and the factors that affect extent of mineral precipitation are examined by a variety of tools, including tracer tests, aqueous inorganic profiles, and surface analysis techniques. At short treatment times, measured porosity losses are due mainly to entrapment of a film of H 2 gas on the iron surfaces and also to Fe(OH) 2 precipitation. Over longer treatment times precipitation of Fe(OH) 2 and FeCO 3 in low carbonate waters and of Fe(OH) 2 , FeCO 3 and CaCO 3 in higher carbonate waters will begin to dominate porosity losses. Preliminary results of an on-going study to control pH in an iron zone by admixing iron sulfide with iron show no difference in extent of carbonate precipitation versus a 100% iron system, suggesting that these systems are supersaturated with respect to carbonate precipitation

  4. A new model for predicting thermodynamic properties of ternary metallic solution from binary components

    International Nuclear Information System (INIS)

    Fang Zheng; Zhang Quanru

    2006-01-01

    A model has been derived to predict thermodynamic properties of ternary metallic systems from those of its three binaries. In the model, the excess Gibbs free energies and the interaction parameter ω 123 for three components of a ternary are expressed as a simple sum of those of the three sub-binaries, and the mole fractions of the components of the ternary are identical with the sub-binaries. This model is greatly simplified compared with the current symmetrical and asymmetrical models. It is able to overcome some shortcomings of the current models, such as the arrangement of the components in the Gibbs triangle, the conversion of mole fractions between ternary and corresponding binaries, and some necessary processes for optimizing the various parameters of these models. Two ternary systems, Mg-Cu-Ni and Cd-Bi-Pb are recalculated to demonstrate the validity and precision of the present model. The calculated results on the Mg-Cu-Ni system are better than those in the literature. New parameters in the Margules equations expressing the excess Gibbs free energies of three binary systems of the Cd-Bi-Pb ternary system are also given

  5. Geographical origin of Sauvignon Blanc wines predicted by mass spectrometry and metal oxide based electronic nose

    Energy Technology Data Exchange (ETDEWEB)

    Berna, Amalia Z., E-mail: Amalia.Berna@csiro.au [CSIRO Entomology and Food Futures Flagship, PO Box 1700, Canberra, ACT 2601 (Australia); Trowell, Stephen [CSIRO Entomology and Food Futures Flagship, PO Box 1700, Canberra, ACT 2601 (Australia); Clifford, David [CSIRO Mathematical and Information Sciences, Locked Bag 17, North Ryde, NSW 1670 (Australia); Cynkar, Wies; Cozzolino, Daniel [The Australian Wine Research Institute, Waite Road, Urrbrae, PO Box 197, Adelaide, SA 5064 (Australia)

    2009-08-26

    Analysis of 34 Sauvignon Blanc wine samples from three different countries and six regions was performed by gas chromatography-mass spectrometry (GC-MS). Linear discriminant analysis (LDA) showed that there were three distinct clusters or classes of wines with different aroma profiles. Wines from the Loire region in France and Australian wines from Tasmania and Western Australia were found to have similar aroma patterns. New Zealand wines from the Marlborough region as well as the Australian ones from Victoria were grouped together based on the volatile composition. Wines from South Australia region formed one discrete class. Seven analytes, most of them esters, were found to be the relevant chemical compounds that characterized the classes. The grouping information obtained by GC-MS, was used to train metal oxide based electronic (MOS-Enose) and mass spectrometry based electronic (MS-Enose) noses. The combined use of solid phase microextraction (SPME) and ethanol removal prior to MOS-Enose analysis, allowed an average error of prediction of the regional origins of Sauvignon Blanc wines of 6.5% compared to 24% when static headspace (SHS) was employed. For MS-Enose, the misclassification rate was higher probably due to the requirement to delimit the m/z range considered.

  6. Geographical origin of Sauvignon Blanc wines predicted by mass spectrometry and metal oxide based electronic nose

    International Nuclear Information System (INIS)

    Berna, Amalia Z.; Trowell, Stephen; Clifford, David; Cynkar, Wies; Cozzolino, Daniel

    2009-01-01

    Analysis of 34 Sauvignon Blanc wine samples from three different countries and six regions was performed by gas chromatography-mass spectrometry (GC-MS). Linear discriminant analysis (LDA) showed that there were three distinct clusters or classes of wines with different aroma profiles. Wines from the Loire region in France and Australian wines from Tasmania and Western Australia were found to have similar aroma patterns. New Zealand wines from the Marlborough region as well as the Australian ones from Victoria were grouped together based on the volatile composition. Wines from South Australia region formed one discrete class. Seven analytes, most of them esters, were found to be the relevant chemical compounds that characterized the classes. The grouping information obtained by GC-MS, was used to train metal oxide based electronic (MOS-Enose) and mass spectrometry based electronic (MS-Enose) noses. The combined use of solid phase microextraction (SPME) and ethanol removal prior to MOS-Enose analysis, allowed an average error of prediction of the regional origins of Sauvignon Blanc wines of 6.5% compared to 24% when static headspace (SHS) was employed. For MS-Enose, the misclassification rate was higher probably due to the requirement to delimit the m/z range considered.

  7. Lead toxicity to Lemna minor predicted using a metal speciation chemistry approach.

    Science.gov (United States)

    Antunes, Paula M C; Kreager, Nancy J

    2014-10-01

    In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5-12.5 mg/L dissolved organic carbon, pH of 5.4-8.3, and water hardness of 8-266 mg/L CaCO3 ). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH} ) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r(2)  = 0.998, p minor and highlight the importance of chemical speciation in Pb-based risk assessments for aquatic macrophytes. © 2014 SETAC.

  8. Accelerated Lifetime Testing Methodology for Lifetime Estimation of Lithium-ion Batteries used in Augmented Wind Power Plants

    DEFF Research Database (Denmark)

    Stroe, Daniel Ioan; Swierczynski, Maciej Jozef; Stan, Ana-Irina

    2014-01-01

    The development of lifetime estimation models for Lithium-ion battery cells, which are working under highly variable mission profiles characteristic for wind power plant applications, requires a lot of expenditures and time resources. Therefore, batteries have to be tested under accelerated...... lifetime ageing conditions. This paper presents a three-stage methodology used for accelerated lifetime testing of Lithium ion batteries. The results obtained at the end of the accelerated ageing process were used for the parametrization of a performance-degradation lifetime model, which is able to predict...... both the capacity fade and the power capability decrease of the selected Lithium-ion battery cells. In the proposed methodology both calendar and cycling lifetime tests were considered since both components are influencing the lifetime of Lithium-ion batteries. Furthermore, the proposed methodology...

  9. Study on the prediction of soil heavy metal elements content based on visible near-infrared spectroscopy

    Science.gov (United States)

    Liu, Jinbao; Zhang, Yang; Wang, Huanyuan; Du, Yichun

    2018-06-01

    The estimation of soils heavy metal content can reflect the impending surroundings of surface, which lays theoretical foundation for using covered vegetation to monitor environment and investigate resource. In this study, the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb in 44 soil samples were collected from Fufeng County, Yangling County and Wugong County, Shaanxi Province and were used as data sources. ASD FieldSpec HR (350-2500 nm), and then the NOR, MSC and SNV of the reflectance were pretreated, the first deviation, second deviation and reflectance reciprocal logarithmic transformation were carried out. The optimal spectroscopy estimation model of nine heavy metal elements of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb was established by regression method. Comparing the diffuse reflectance characteristics of different heavy metal contents and the effect of different pretreatment methods on the establishment of soil heavy metal spectral inversion model. The results of chemical analysis show that there was a serious Hg pollution in the study area, and the Cd content was close to the critical value. The results show that: (1) NOR, MSC and SNV were adopted for the acquisition of visible near-infrared. Combining differential transformation can improve the information of heavy metal elements in the soil, and use the correlation band energy Significantly improve the stability and predictability of the model. (2) The modeling accuracy of the optimal model of nine heavy metal spectra of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb by PLSR method were 0.70, 0.79, 0.69, 0.81, 0.86, 0.58, 0.55, 0.99, 0.62. (3) The optimal estimation model of different elements using different treatment methods has better stability and higher precision, and can realize the rapid prediction of nine kinds of heavy metal elements in this region.

  10. Study on the prediction of soil heavy metal elements content based on visible near-infrared spectroscopy.

    Science.gov (United States)

    Liu, Jinbao; Zhang, Yang; Wang, Huanyuan; Du, Yichun

    2018-06-15

    The estimation of soils heavy metal content can reflect the impending surroundings of surface, which lays theoretical foundation for using covered vegetation to monitor environment and investigate resource. In this study, the contents of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb in 44 soil samples were collected from Fufeng County, Yangling County and Wugong County, Shaanxi Province and were used as data sources. ASD FieldSpec HR (350-2500nm), and then the NOR, MSC and SNV of the reflectance were pretreated, the first deviation, second deviation and reflectance reciprocal logarithmic transformation were carried out. The optimal spectroscopy estimation model of nine heavy metal elements of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb was established by regression method. Comparing the diffuse reflectance characteristics of different heavy metal contents and the effect of different pretreatment methods on the establishment of soil heavy metal spectral inversion model. The results of chemical analysis show that there was a serious Hg pollution in the study area, and the Cd content was close to the critical value. The results show that: (1) NOR, MSC and SNV were adopted for the acquisition of visible near-infrared. Combining differential transformation can improve the information of heavy metal elements in the soil, and use the correlation band energy Significantly improve the stability and predictability of the model. (2) The modeling accuracy of the optimal model of nine heavy metal spectra of Cr, Mn, Ni, Cu, Zn, As, Cd, Hg and Pb by PLSR method were 0.70, 0.79, 0.69, 0.81, 0.86, 0.58, 0.55, 0.99, 0.62. (3) The optimal estimation model of different elements using different treatment methods has better stability and higher precision, and can realize the rapid prediction of nine kinds of heavy metal elements in this region. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. B meson lifetime measurement

    International Nuclear Information System (INIS)

    Piccolo, M.

    1989-01-01

    The lifetime of hadrons containing b-quark has been the subject of extensive experimental work and theoretical speculation; its importance is due to implications on some of the fundamental parameters of the Standard Model, such as the top quark mass and the mixing angles. Since the pioneer measurements of the MAC and MARK II collaborations at PEP in 1983 the progress has been impressive; but many issues still remain open and await further study. In this paper the field's present status is discussed. An overview of the theoretical motivations for this measurements in the Standard Model framework is done. Then the experimental techniques used are reviewed, emphasizing the most recent measurements. A comparison of the results obtained is done and systematic errors are discussed. In conclusion there are some remarks on the further developments foreseen in the near future

  12. Positron lifetime spectroscopy of internally oxidised Ag-In alloys

    International Nuclear Information System (INIS)

    Wegner, D.; Lieb, K.P.

    1989-01-01

    The effects of In 2 O 3 precipitates on positron lifetimes after internal oxidation of α-Ag-In alloys have been investigated. A positron trap associated with the lifetime τ 205(3) ps was detected. On the basis of the experimental results obtained for different oxidation kinetics parameters, a trapping model is proposed according to which positrons thermalised in a dislocation field around oxide precipitates are trapped at the oxide/metal phase boundary. The transition from internal to external oxidation of Ag-In was also studied. The positron lifetime in In 2 O 3 was measured to be τ = 263(8) ps. (author)

  13. A study on prediction of metal loss by flow-accelerated corrosion in the CANDU NPP secondary piping systems

    International Nuclear Information System (INIS)

    Shim, S. H.; Song, J. S.; Yoon, K. B.; Hwang, K. M.; Jin, T. E.; Lee, S. H.; Kim, W. S.

    2001-01-01

    Flow-Accelerated Corrosion(FAC) is a phenomenon that results in metal loss from piping, vessels, and equipment made of carbon steel. FAC occurs only under certain conditions of flow, chemistry, geometry, and material. Unfortunately, those conditions are in much of the high-energy piping in nuclear and fossil-fueled power plants. Also, for domestic NPP secondary pipings whose operating time become longer, more evidences of FAC have been reported. The authors are studying on FAC management using CHECWORKS, computer code developed by EPRI. This paper is on the prediction results of metal loss by FAC in the one of CANDU type NPP secondary piping systems

  14. Prediction of molecular separation of polar-apolar mixtures on heterogeneous metal-organic frameworks: HKUST-1.

    Science.gov (United States)

    Van Assche, Tom R C; Duerinck, Tim; Van der Perre, Stijn; Baron, Gino V; Denayer, Joeri F M

    2014-07-08

    Due to the combination of metal ions and organic linkers and the presence of different types of cages and channels, metal-organic frameworks often possess a large structural and chemical heterogeneity, complicating their adsorption behavior, especially for polar-apolar adsorbate mixtures. By allocating isotherms to individual subunits in the structure, the ideal adsorbed solution theory (IAST) can be adjusted to cope with this heterogeneity. The binary adsorption of methanol and n-hexane on HKUST-1 is analyzed using this segregated IAST (SIAST) approach and offers a significant improvement over the standard IAST model predictions. It identifies the various HKUST-1 cages to have a pronounced polar or apolar adsorptive behavior.

  15. Slow and stopped light in active gain composite materials of metal nanoparticles. Ultralarge group index-bandwidth product predicted

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang-Hyon; Choe, Song-Hyok [Institute of Lasers, State Academy of Sciences, Unjong District, Pyongyang (Korea, Democratic People' s Republic of)

    2017-08-15

    Chip-compatible slow light devices with large group index-bandwidth products and low losses are of great interest in the community of modern photonics. In this work, active gain materials containing metal nanoparticles are proposed as the slow and stopped light materials. Gain-assisted high field enhancement in metal nanoparticles and the resultant strong dispersion lead to such phenomena. From the Maxwell-Garnett model, it is revealed that the metal nanocomposite exhibits the infinitely large group index when the gain of the host medium and the filling factor of metal nanoparticles satisfy a critical condition. For the gain of the host above the critical value, one can observe slowing down effect with amplification of light pulses. Significantly large group index-bandwidth products, which vary from a few to several thousand or even infinity depending on the gain value of the host medium, have been numerically predicted in active silica glasses containing spheroidal metal nanoparticles, as examples. The proposed scheme inherently provides the widely varying operating spectral range by changing the aspect ratio of metal nanoparticles and chip-compatibility with low cost. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Atomistic approach to predict the glass-forming ability in Zr–Cu–Al ternary metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.Y. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Liu, X.J. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zheng, G.P. [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Niu, X.R. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Liu, C.T., E-mail: chainliu@cityu.edu.hk [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

    2015-04-05

    Highlights: • An atomistic approach has been developed to predict the glass forming ability (GFA) in Zr–Cu–Al ternary alloy system. • Both of the thermodynamic and structure-dependent kinetic effects to glass formation have been taken into account. • The first-principles calculation and molecular dynamics simulation have been performed. • The approach predicts the best glass former in the model Zr–Cu–Al alloy system. • The predicted GFA is consistent with various experimental results. - Abstract: Prediction of composition-dependent glass-forming ability (GFA) remains to be a key scientific challenge in the metallic-glass community, especially in multi-component alloy systems. In the present study, we apply an atomistic approach to predict the trend of GFA effectively in the Zr–Cu–Al ternary alloy system from alloy compositions alone. This approach is derived from the first-principles calculations based on the density-functional theory and molecular dynamic (MD) simulations. By considering of both the thermodynamic and atomic-structure induced kinetic effects, the predicted GFA trend from this approach shows an excellent agreement with experimental data available in this alloy system, manifesting its capability of seeking metallic glasses with superior GFA in ternary alloy systems.

  17. Recycling of Metals

    DEFF Research Database (Denmark)

    Damgaard, Anders; Christensen, Thomas Højlund

    2011-01-01

    Metals like iron and aluminium are produced from mineral ore and used for a range of products, some of which have very short lifetimes and thus constitute a major fraction of municipal waste. Packaging in terms of cans, foils and containers are products with a short lifetime. Other products like...... appliances, vehicles and buildings, containing iron and aluminium metals, have long lifetimes before they end up in the waste stream. The recycling of production waste and postconsumer metals has a long history in the metal industry. Some metal smelters are today entirely based on scarp metals. This chapter...... describes briefly how iron and aluminium are produced and how scrap metal is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of metal recycling. Copper and other metals are also found in waste but in much smaller...

  18. Energy Savings Lifetimes and Persistence

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Ian M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schiller, Steven R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Todd, Annika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Billingsley, Megan A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goldman, Charles A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-02-01

    This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from a national collection of costs and savings for electric efficiency programs and portfolios.

  19. Positron lifetimes in deformed copper

    International Nuclear Information System (INIS)

    Hinode, Kenji; Tanigawa, Shoichiro; Doyama, Masao

    1976-01-01

    Positron lifetime measurements were performed for Cu samples with different densities of lattice defects. The lifetime spectra were successfully resolved into two components with the help of the well established analysis program. Obtained results were quite consistent with those expected from the trapping model. The positron trapping mechanism from free to trapped states and the initial condition of the model were especially checked. Deduced values obtained for tau sub(c) (lifetime of free positrons) and tau sub(t) (lifetime of trapped positrons) were 122+-5 psec and 176+-5 psec, respectively. (auth.)

  20. Prediction of size-fractionated airborne particle-bound metals using MLR, BP-ANN and SVM analyses.

    Science.gov (United States)

    Leng, Xiang'zi; Wang, Jinhua; Ji, Haibo; Wang, Qin'geng; Li, Huiming; Qian, Xin; Li, Fengying; Yang, Meng

    2017-08-01

    Size-fractionated heavy metal concentrations were observed in airborne particulate matter (PM) samples collected from 2014 to 2015 (spanning all four seasons) from suburban (Xianlin) and industrial (Pukou) areas in Nanjing, a megacity of southeast China. Rapid prediction models of size-fractionated metals were established based on multiple linear regression (MLR), back propagation artificial neural network (BP-ANN) and support vector machine (SVM) by using meteorological factors and PM concentrations as input parameters. About 38% and 77% of PM 2.5 concentrations in Xianlin and Pukou, respectively, were beyond the Chinese National Ambient Air Quality Standard limit of 75 μg/m 3 . Nearly all elements had higher concentrations in industrial areas, and in winter among the four seasons. Anthropogenic elements such as Pb, Zn, Cd and Cu showed larger percentages in the fine fraction (ø≤2.5 μm), whereas the crustal elements including Al, Ba, Fe, Ni, Sr and Ti showed larger percentages in the coarse fraction (ø > 2.5 μm). SVM showed a higher training correlation coefficient (R), and lower mean absolute error (MAE) as well as lower root mean square error (RMSE), than MLR and BP-ANN for most metals. All the three methods showed better prediction results for Ni, Al, V, Cd and As, whereas relatively poor for Cr and Fe. The daily airborne metal concentrations in 2015 were then predicted by the fully trained SVM models and the results showed the heaviest pollution of airborne heavy metals occurred in December and January, whereas the lightest pollution occurred in June and July. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Differences in SEM-AVS and ERM-ERL predictions of sediment impacts from metals in two US Virgin Islands marinas.

    Science.gov (United States)

    Hinkey, Lynne M; Zaidi, Baqar R

    2007-02-01

    Two US Virgin Islands marinas were examined for potential metal impacts by comparing sediment chemistry data with two sediment quality guideline (SQG) values: the ratio of simultaneously extractable metals to acid volatile sulfides (SEM-AVS), and effects range-low and -mean (ERL-ERM) values. ERL-ERMs predicted the marina/boatyard complex (IBY: 2118 microg/g dry weight total metals, two exceeded ERMs) would have greater impacts than the marina with no boatyard (CBM: 231 microg/g dry weight total metals, no ERMs exceeded). The AVS-SEM method predicted IBY would have fewer effects due to high AVS-forming metal sulfide complexes, reducing trace metal bioavailability. These contradictory predictions demonstrate the importance of validating the results of either of these methods with other toxicity measures before making any management or regulatory decisions regarding boating and marina impacts. This is especially important in non-temperate areas where sediment quality guidelines have not been validated.

  2. Concentration addition and independent action model: Which is better in predicting the toxicity for metal mixtures on zebrafish larvae.

    Science.gov (United States)

    Gao, Yongfei; Feng, Jianfeng; Kang, Lili; Xu, Xin; Zhu, Lin

    2018-01-01

    The joint toxicity of chemical mixtures has emerged as a popular topic, particularly on the additive and potential synergistic actions of environmental mixtures. We investigated the 24h toxicity of Cu-Zn, Cu-Cd, and Cu-Pb and 96h toxicity of Cd-Pb binary mixtures on the survival of zebrafish larvae. Joint toxicity was predicted and compared using the concentration addition (CA) and independent action (IA) models with different assumptions in the toxic action mode in toxicodynamic processes through single and binary metal mixture tests. Results showed that the CA and IA models presented varying predictive abilities for different metal combinations. For the Cu-Cd and Cd-Pb mixtures, the CA model simulated the observed survival rates better than the IA model. By contrast, the IA model simulated the observed survival rates better than the CA model for the Cu-Zn and Cu-Pb mixtures. These findings revealed that the toxic action mode may depend on the combinations and concentrations of tested metal mixtures. Statistical analysis of the antagonistic or synergistic interactions indicated that synergistic interactions were observed for the Cu-Cd and Cu-Pb mixtures, non-interactions were observed for the Cd-Pb mixtures, and slight antagonistic interactions for the Cu-Zn mixtures. These results illustrated that the CA and IA models are consistent in specifying the interaction patterns of binary metal mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Probabilistic approaches to accounting for data variability in the practical application of bioavailability in predicting aquatic risks from metals.

    Science.gov (United States)

    Ciffroy, Philippe; Charlatchka, Rayna; Ferreira, Daniel; Marang, Laura

    2013-07-01

    The biotic ligand model (BLM) theoretically enables the derivation of environmental quality standards that are based on true bioavailable fractions of metals. Several physicochemical variables (especially pH, major cations, dissolved organic carbon, and dissolved metal concentrations) must, however, be assigned to run the BLM, but they are highly variable in time and space in natural systems. This article describes probabilistic approaches for integrating such variability during the derivation of risk indexes. To describe each variable using a probability density function (PDF), several methods were combined to 1) treat censored data (i.e., data below the limit of detection), 2) incorporate the uncertainty of the solid-to-liquid partitioning of metals, and 3) detect outliers. From a probabilistic perspective, 2 alternative approaches that are based on log-normal and Γ distributions were tested to estimate the probability of the predicted environmental concentration (PEC) exceeding the predicted non-effect concentration (PNEC), i.e., p(PEC/PNEC>1). The probabilistic approach was tested on 4 real-case studies based on Cu-related data collected from stations on the Loire and Moselle rivers. The approach described in this article is based on BLM tools that are freely available for end-users (i.e., the Bio-Met software) and on accessible statistical data treatments. This approach could be used by stakeholders who are involved in risk assessments of metals for improving site-specific studies. Copyright © 2013 SETAC.

  4. Predicted stability, structures, and magnetism of 3d transition metal nitrides: the M4N phases

    NARCIS (Netherlands)

    Fang, C.M.; Koster, R.S.; Li, W.F.; van Huis, M.A.

    2014-01-01

    The 3d transition metal nitrides M4N (Sc4N, Ti4N, V4N, Cr4N, Mn4N, Fe4N, Co4N, Ni4N, and Cu4N) have unique phase relationships, crystal structures, and electronic and magnetic properties. Here we present a systematic density functional theory (DFT) study on these transition metal nitrides, assessing

  5. Outgas analysis of mechanical cryocoolers for long lifetime

    Science.gov (United States)

    Sato, Yoichi; Shinozaki, Keisuke; Sawada, Kenichiro; Sugita, Hiroyuki; Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; Nakagawa, Takao; Tsunematsu, Shoji; Otsuka, Kiyomi; Kanao, Kenichi; Yoshida, Seiji; Narasaki, Katsuhiro

    2017-12-01

    Mechanical cryocoolers for space applications are required to have high reliability to achieve long-term operation in orbit. ASTRO-H (Hitomi), the 6th Japanese X-ray astronomy mission, has a major scientific instrument onboard-the Soft X-ray Spectrometer (SXS) with several 20K-class two-stage Stirling (2ST) coolers and a 4K-class Joule Thomson (JT) cooler, which must operate for 3 years to ensure the lifetime of liquid helium as a cryogen for cooling of its detectors [1,2]. Other astronomical missions such as SPICA [3,4], LiteBIRD [5], and Athena [6] also have top requirements for these mechanical cryocoolers, including a 1K-class JT cooler to be operated for more than 3-5 years with no cryogen system. The reliability and lifetime of mechanical cryocoolers are generally understood to depend on (1) mechanical wear of the piston seal and valve seal, and (2) He working gas contaminated by impurity outgases, mainly H2O and CO2 released from the materials in the components of the cryocoolers. The second factor could be critical relative to causing blockage in the JT heat exchanger plumbing and the JT orifice or resulting in blockage in the Stirling regenerator and thereby degrading its performance. Thus, reducing the potential for outgassing in the cryocooler design and fabrication process, and predicting the total amount of outgases in the cryocooler are very important to ensure cryocooler lifetime and cooling performance in orbit. This paper investigates the outgas analysis of the 2ST and the 1K/4K-JT coolers for achieving a long lifetime. First, gas analysis was conducted for the materials and components of the mechanical cryocoolers, focusing on non-metallic materials as impurity gas sources. Then gas analysis of the mechanical wear effect of the piston seal materials and linear ball bearings was investigated. Finally, outgassing from a fully assembled cryocooler was measured to evaluate whether the outgas reduction process works properly to meet the requirement

  6. SIRTF thermal design modifications to increase lifetime

    Science.gov (United States)

    Petrick, S. W.

    1993-01-01

    An effort was made to increase the predicted lifetime of the SIRTF dewar by lowering the exterior shell temperature, increasing the radiated energy from the vapor cooled shields and reconfiguring the vapor cooled shields. The lifetime increases can be used to increase the scientific return from the mission and as a trade-off against mass and cost. This paper describes the configurations studied, the steady state thermal model used, the analytical methods and the results of the analysis. Much of the heat input to the outside dewar shell is radiative heat transfer from the solar panel. To lower the shell temperature, radiative cooled shields were placed between the solar panel and the dewar shell and between the bus and the dewar shell. Analysis showed that placing a radiator on the outer vapor cooled shield had a significant effect on lifetime. Lengthening the distance between the outer shell and the point where the vapor cooled shields are attached to the support straps also improved lifetime.

  7. Multi-Scale Modeling for Predicting the Stiffness and Strength of Hollow-Structured Metal Foams with Structural Hierarchy

    Directory of Open Access Journals (Sweden)

    Yong Yi

    2018-03-01

    Full Text Available This work was inspired by previous experiments which managed to establish an optimal template-dealloying route to prepare ultralow density metal foams. In this study, we propose a new analytical–numerical model of hollow-structured metal foams with structural hierarchy to predict its stiffness and strength. The two-level model comprises a main backbone and a secondary nanoporous structure. The main backbone is composed of hollow sphere-packing architecture, while the secondary one is constructed of a bicontinuous nanoporous network proposed to describe the nanoscale interactions in the shell. Firstly, two nanoporous models with different geometries are generated by Voronoi tessellation, then the scaling laws of the mechanical properties are determined as a function of relative density by finite volume simulation. Furthermore, the scaling laws are applied to identify the uniaxial compression behavior of metal foams. It is shown that the thickness and relative density highly influence the Young’s modulus and yield strength, and vacancy defect determines the foams being self-supported. The present study provides not only new insights into the mechanical behaviors of both nanoporous metals and metal foams, but also a practical guide for their fabrication and application.

  8. Lifetime Improvement by Battery Scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Schmitt, Jens B.; Haverkort, Boudewijn R.H.M.

    The use of mobile devices is often limited by the lifetime of their batteries. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to

  9. Lifetime improvement by battery scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.

    The use of mobile devices is often limited by the lifetime of its battery. For devices that have multiple batteries or that have the option to connect an extra battery, battery scheduling, thereby exploiting the recovery properties of the batteries, can help to extend the system lifetime. Due to the

  10. Laser Direct Metal Deposition of 2024 Al Alloy: Trace Geometry Prediction via Machine Learning.

    Science.gov (United States)

    Caiazzo, Fabrizia; Caggiano, Alessandra

    2018-03-19

    Laser direct metal deposition is an advanced additive manufacturing technology suitably applicable in maintenance, repair, and overhaul of high-cost products, allowing for minimal distortion of the workpiece, reduced heat affected zones, and superior surface quality. Special interest is growing for the repair and coating of 2024 aluminum alloy parts, extensively utilized for a wide range of applications in the automotive, military, and aerospace sectors due to its excellent plasticity, corrosion resistance, electric conductivity, and strength-to-weight ratio. A critical issue in the laser direct metal deposition process is related to the geometrical parameters of the cross-section of the deposited metal trace that should be controlled to meet the part specifications. In this research, a machine learning approach based on artificial neural networks is developed to find the correlation between the laser metal deposition process parameters and the output geometrical parameters of the deposited metal trace produced by laser direct metal deposition on 5-mm-thick 2024 aluminum alloy plates. The results show that the neural network-based machine learning paradigm is able to accurately estimate the appropriate process parameters required to obtain a specified geometry for the deposited metal trace.

  11. Laser Direct Metal Deposition of 2024 Al Alloy: Trace Geometry Prediction via Machine Learning

    Directory of Open Access Journals (Sweden)

    Fabrizia Caiazzo

    2018-03-01

    Full Text Available Laser direct metal deposition is an advanced additive manufacturing technology suitably applicable in maintenance, repair, and overhaul of high-cost products, allowing for minimal distortion of the workpiece, reduced heat affected zones, and superior surface quality. Special interest is growing for the repair and coating of 2024 aluminum alloy parts, extensively utilized for a wide range of applications in the automotive, military, and aerospace sectors due to its excellent plasticity, corrosion resistance, electric conductivity, and strength-to-weight ratio. A critical issue in the laser direct metal deposition process is related to the geometrical parameters of the cross-section of the deposited metal trace that should be controlled to meet the part specifications. In this research, a machine learning approach based on artificial neural networks is developed to find the correlation between the laser metal deposition process parameters and the output geometrical parameters of the deposited metal trace produced by laser direct metal deposition on 5-mm-thick 2024 aluminum alloy plates. The results show that the neural network-based machine learning paradigm is able to accurately estimate the appropriate process parameters required to obtain a specified geometry for the deposited metal trace.

  12. Metal-ceramic materials. Study and prediction of effective mechanical properties

    International Nuclear Information System (INIS)

    Karakulov, Valerii V.; Smolin, Igor Yu.

    2016-01-01

    Mechanical behavior of stochastic metal-ceramic composite materials was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites, whose structure consists of a metal matrix and randomly distributed ceramic inclusions, was numerically simulated. The results of the numerical simulation were used for evaluation of the effective elastic and strength properties of metal-ceramic materials with different parameters of the structure. The values of the effective mechanical properties of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites was determined.

  13. Lifetime of {sup 44}Ti as probe for supernova models

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, J; Meissner, J; Schatz, H; Stech, E; Tischhauser, P; Wiescher, M [Univ. of Notre Dame, Notre Dame, IN (United States); Bazin, D; Harkewicz, R; Hellstroem, M; Sherrill, B; Steiner, M [Michigan State Univ., East Lansing, MI (United States); Boyd, R N [Ohio State Univ., Columbus, OH (United States); Buchmann, L [TRIUMF, Vancouver, BC (Canada); Hartmann, D H [Clemson Univ., Clemson, SC (United States); Hinnefeld, J D [Indiana Univ. South Bend, South Bend, IN (United States)

    1998-06-01

    The recent observation of {sup 44}Ti radioactivity in the supernova remnant Cassiopeia A with the Compton Gamma Ray Observatory allows the determination of the absolute amount of {sup 44}Ti. This provides a test for current supernova models. The main uncertainty is the lifetime of {sup 44}Ti. We report a new measurement of the lifetime of {sup 44}Ti applying a novel technique. A mixed radioactive beam containing {sup 44}Ti as well as {sup 22}Na was implanted and the resulting {gamma}-activity was measured. This allowed the determination of the lifetime of {sup 44}Ti relative to the lifetime of {sup 22}Na, {tau} = (87.0 {+-} 1.9) y. With this lifetime, the {sup 44}Ti abundance agrees with theoretical predictions within the remaining observational uncertainties. (orig.)

  14. A new code for predicting the thermo-mechanical and irradiation behavior of metallic fuels in sodium fast reactors

    Energy Technology Data Exchange (ETDEWEB)

    Karahan, Aydin, E-mail: karahan@mit.ed [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology (United States); Buongiorno, Jacopo [Center for Advanced Nuclear Energy Systems, Nuclear Science and Engineering Department, Massachusetts Institute of Technology (United States)

    2010-01-31

    An engineering code to predict the irradiation behavior of U-Zr and U-Pu-Zr metallic alloy fuel pins and UO{sub 2}-PuO{sub 2} mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named Fuel Engineering and Structural analysis Tool (FEAST). FEAST has several modules working in coupled form with an explicit numerical algorithm. These modules describe fission gas release and fuel swelling, fuel chemistry and restructuring, temperature distribution, fuel-clad chemical interaction, and fuel and clad mechanical analysis including transient creep-fracture for the clad. Given the fuel pin geometry, composition and irradiation history, FEAST can analyze fuel and clad thermo-mechanical behavior at both steady-state and design-basis (non-disruptive) transient scenarios. FEAST was written in FORTRAN-90 and has a simple input file similar to that of the LWR fuel code FRAPCON. The metal-fuel version is called FEAST-METAL, and is described in this paper. The oxide-fuel version, FEAST-OXIDE is described in a companion paper. With respect to the old Argonne National Laboratory code LIFE-METAL and other same-generation codes, FEAST-METAL emphasizes more mechanistic, less empirical models, whenever available. Specifically, fission gas release and swelling are modeled with the GRSIS algorithm, which is based on detailed tracking of fission gas bubbles within the metal fuel. Migration of the fuel constituents is modeled by means of thermo-transport theory. Fuel-clad chemical interaction models based on precipitation kinetics were developed for steady-state operation and transients. Finally, a transient intergranular creep-fracture model for the clad, which tracks the nucleation and growth of the cavities at the grain boundaries, was developed for and implemented in the code. Reducing the empiricism in the constitutive models should make it more acceptable to extrapolate FEAST-METAL to new fuel compositions and higher burnup, as envisioned in advanced sodium

  15. A new code for predicting the thermo-mechanical and irradiation behavior of metallic fuels in sodium fast reactors

    International Nuclear Information System (INIS)

    Karahan, Aydin; Buongiorno, Jacopo

    2010-01-01

    An engineering code to predict the irradiation behavior of U-Zr and U-Pu-Zr metallic alloy fuel pins and UO 2 -PuO 2 mixed oxide fuel pins in sodium-cooled fast reactors was developed. The code was named Fuel Engineering and Structural analysis Tool (FEAST). FEAST has several modules working in coupled form with an explicit numerical algorithm. These modules describe fission gas release and fuel swelling, fuel chemistry and restructuring, temperature distribution, fuel-clad chemical interaction, and fuel and clad mechanical analysis including transient creep-fracture for the clad. Given the fuel pin geometry, composition and irradiation history, FEAST can analyze fuel and clad thermo-mechanical behavior at both steady-state and design-basis (non-disruptive) transient scenarios. FEAST was written in FORTRAN-90 and has a simple input file similar to that of the LWR fuel code FRAPCON. The metal-fuel version is called FEAST-METAL, and is described in this paper. The oxide-fuel version, FEAST-OXIDE is described in a companion paper. With respect to the old Argonne National Laboratory code LIFE-METAL and other same-generation codes, FEAST-METAL emphasizes more mechanistic, less empirical models, whenever available. Specifically, fission gas release and swelling are modeled with the GRSIS algorithm, which is based on detailed tracking of fission gas bubbles within the metal fuel. Migration of the fuel constituents is modeled by means of thermo-transport theory. Fuel-clad chemical interaction models based on precipitation kinetics were developed for steady-state operation and transients. Finally, a transient intergranular creep-fracture model for the clad, which tracks the nucleation and growth of the cavities at the grain boundaries, was developed for and implemented in the code. Reducing the empiricism in the constitutive models should make it more acceptable to extrapolate FEAST-METAL to new fuel compositions and higher burnup, as envisioned in advanced sodium reactors

  16. Fluorescence lifetime evaluation of whole soils from the Amazon rainforest.

    Science.gov (United States)

    Nicolodelli, Gustavo; Tadini, Amanda Maria; Nogueira, Marcelo Saito; Pratavieira, Sebastião; Mounier, Stephane; Huaman, Jose Luis Clabel; Dos Santos, Cléber Hilário; Montes, Célia Regina; Milori, Débora Marcondes Bastos Pereira

    2017-08-20

    Time-resolved fluorescence spectroscopy (TRFS) is a new tool that can be used to investigate processes of interaction between metal ions and organic matter (OM) in soils, providing a specific analysis of the structure and dynamics of macromolecules. To the best of our knowledge, there are no studies in the literature reporting the use of this technique applied to whole/non-fractionated soil samples, making it a potential method for use in future studies. This work describes the use of TRFS to evaluate the fluorescence lifetimes of OM of whole soils from the Amazon region. Analysis was made of pellets of soils from an oxisol-spodosol system, collected in São Gabriel da Cachoeira (Amazonas, Brazil). The fluorescence lifetimes in the oxisol-spodosol system were attributed to two different fluorophores. One was related to complexation of an OM fraction with metals, resulting in a shorter fluorophore lifetime. A short fluorescence lifetime (2-12 ns) could be associated with simpler structures of the OM, while a long lifetime (19-66 ns) was associated with more complex OM structures. This new TRFS technique for analysis of the fluorescence lifetime in whole soil samples complies with the principles of green chemistry.

  17. Predicting heavy metals' adsorption edges and adsorption isotherms on MnO2 with the parameters determined from Langmuir kinetics.

    Science.gov (United States)

    Hu, Qinghai; Xiao, Zhongjin; Xiong, Xinmei; Zhou, Gongming; Guan, Xiaohong

    2015-01-01

    Although surface complexation models have been widely used to describe the adsorption of heavy metals, few studies have verified the feasibility of modeling the adsorption kinetics, edge, and isotherm data with one pH-independent parameter. A close inspection of the derivation process of Langmuir isotherm revealed that the equilibrium constant derived from the Langmuir kinetic model, KS-kinetic, is theoretically equivalent to the adsorption constant in Langmuir isotherm, KS-Langmuir. The modified Langmuir kinetic model (MLK model) and modified Langmuir isotherm model (MLI model) incorporating pH factor were developed. The MLK model was employed to simulate the adsorption kinetics of Cu(II), Co(II), Cd(II), Zn(II) and Ni(II) on MnO2 at pH3.2 or 3.3 to get the values of KS-kinetic. The adsorption edges of heavy metals could be modeled with the modified metal partitioning model (MMP model), and the values of KS-Langmuir were obtained. The values of KS-kinetic and KS-Langmuir are very close to each other, validating that the constants obtained by these two methods are basically the same. The MMP model with KS-kinetic constants could predict the adsorption edges of heavy metals on MnO2 very well at different adsorbent/adsorbate concentrations. Moreover, the adsorption isotherms of heavy metals on MnO2 at various pH levels could be predicted reasonably well by the MLI model with the KS-kinetic constants. Copyright © 2014. Published by Elsevier B.V.

  18. Prediction of residual stress for dissimilar metals welding at nuclear power plants using fuzzy neural network models

    International Nuclear Information System (INIS)

    Na, Man Gyun; Kim, Jin Weon; Lim, Dong Hyuk

    2007-01-01

    A fuzzy neural network model is presented to predict residual stress for dissimilar metal welding under various welding conditions. The fuzzy neural network model, which consists of a fuzzy inference system and a neuronal training system, is optimized by a hybrid learning method that combines a genetic algorithm to optimize the membership function parameters and a least squares method to solve the consequent parameters. The data of finite element analysis are divided into four data groups, which are split according to two end-section constraints and two prediction paths. Four fuzzy neural network models were therefore applied to the numerical data obtained from the finite element analysis for the two end-section constraints and the two prediction paths. The fuzzy neural network models were trained with the aid of a data set prepared for training (training data), optimized by means of an optimization data set and verified by means of a test data set that was different (independent) from the training data and the optimization data. The accuracy of fuzzy neural network models is known to be sufficiently accurate for use in an integrity evaluation by predicting the residual stress of dissimilar metal welding zones

  19. Effect doses for protection of human health predicted from physicochemical properties of metals/metalloids.

    Science.gov (United States)

    Wang, Ying; Wu, Fengchang; Liu, Yuedan; Mu, Yunsong; Giesy, John P; Meng, Wei; Hu, Qing; Liu, Jing; Dang, Zhi

    2018-01-01

    Effect doses (EDs) of metals/metalloids, usually obtained from toxicological experiments are required for developing environmental quality criteria/standards for use in assessment of hazard or risks. However, because in vivo tests are time-consuming, costly and sometimes impossible to conduct, among more than 60 metals/metalloids, there are sufficient data for development of EDs for only approximately 25 metals/metalloids. Hence, it was deemed a challenge to derive EDs for additional metals by use of alternative methods. This study found significant relationships between EDs and physicochemical parameters for twenty-five metals/metalloids. Elements were divided into three classes and then three individual empirical models were developed based on the most relevant parameters for each class. These parameters included log-βn, ΔE 0 and X m 2 r, respectively (R 2  = 0.988, 0.839, 0.871, P metalloids. Here, these alternative models for deriving thresholds of toxicity that could be used to perform preliminarily, screen-level health assessments for metals are presented. Copyright © 2017. Published by Elsevier Ltd.

  20. Lifetime costs of cerebral palsy

    DEFF Research Database (Denmark)

    Kruse, Marie; Michelsen, Susan Ishøy; Flachs, Esben Meulengracht

    2009-01-01

    This study quantified the lifetime costs of cerebral palsy (CP) in a register-based setting. It was the first study outside the US to assess the lifetime costs of CP. The lifetime costs attributable to CP were divided into three categories: health care costs, productivity costs, and social costs....... social care costs and productivity costs associated with CP point to a potential gain from labour market interventions that benefit individuals with CP.......This study quantified the lifetime costs of cerebral palsy (CP) in a register-based setting. It was the first study outside the US to assess the lifetime costs of CP. The lifetime costs attributable to CP were divided into three categories: health care costs, productivity costs, and social costs...... in 2000. The prevalence of CP in eastern Denmark was approximately 1.7 per 1000. Information on productivity and the use of health care was retrieved from registers. The lifetime cost of CP was about euro860 000 for men and about euro800 000 for women. The largest component was social care costs...

  1. Development and Validation of a Biodynamic Model for Mechanistically Predicting Metal Accumulation in Fish-Parasite Systems.

    Directory of Open Access Journals (Sweden)

    T T Yen Le

    Full Text Available Because of different reported effects of parasitism on the accumulation of metals in fish, it is important to consider parasites while interpreting bioaccumulation data from biomonitoring programmes. Accordingly, the first step is to take parasitism into consideration when simulating metal bioaccumulation in the fish host under laboratory conditions. In the present study, the accumulation of metals in fish-parasite systems was simulated by a one-compartment toxicokinetic model and compared to uninfected conspecifics. As such, metal accumulation in fish was assumed to result from a balance of different uptake and loss processes depending on the infection status. The uptake by parasites was considered an efflux from the fish host, similar to elimination. Physiological rate constants for the uninfected fish were parameterised based on the covalent index and the species weight while the parameterisation for the infected fish was carried out based on the reported effects of parasites on the uptake kinetics of the fish host. The model was then validated for the system of the chub Squalius cephalus and the acanthocephalan Pomphorhynchus tereticollis following 36-day exposure to waterborne Pb. The dissolved concentration of Pb in the exposure tank water fluctuated during the exposure, ranging from 40 to 120 μg/L. Generally, the present study shows that the one-compartment model can be an effective method for simulating the accumulation of metals in fish, taking into account effects of parasitism. In particular, the predicted concentrations of Cu, Fe, Zn, and Pb in the uninfected chub as well as in the infected chub and the acanthocephalans were within one order of magnitude of the measurements. The variation in the absorption efficiency and the elimination rate constant of the uninfected chub resulted in variations of about one order of magnitude in the predicted concentrations of Pb. Inclusion of further assumptions for simulating metal accumulation

  2. Labile rhizosphere soil solution fraction for prediction of bioavailability of heavy metals and rare earth elements to plants.

    Science.gov (United States)

    Shan, Xiao-Quan; Wang, Zhongwen; Wang, Weisheng; Zhang, Shuzhen; Wen, Bei

    2003-02-01

    A labile rhizosphere soil solution fraction has been recommended to predict the bioavailability of heavy metals and rare earth elements to plants. This method used moist rhizosphere soil in combination with a mixture of 0.01 mol L(-1) of low-molecular-weight organic acids (LMWOAs) as extractant. The extracted soil solutions were fractionated into two colloidal fractions of soil solution fraction, F(lrss). For the soil solutions extracted with a mixture of LMWOAs the concentrations of heavy metals and rare earth elements in F(2) and F(3) were quite similar. However, the mean concentrations of Cr, Ni, Zn, Cu, Pb, Cd, La, Ce, Pr, and Nd in F(lrss) accounted for 79.9%, 91.3%, 90.8%, 60.1%, 77.5%, 75.3%, 81.2%, 77.2%, 80.3%, and 79.5%, respectively, of their concentrations in F(2). In contrast, there were no differences in the extractable metal concentrations between the three fractions while the first step of the method recommended by the European Community of Reference (BCR), where 0.1 mol L(-1) acetic acid was used as an extractant. The single correlation analysis was made between metal concentrations in the different fractions of soil solutions and their concentrations in wheat. If the first step of BCR method was used there was no good correlation between heavy metals in soil pools and that in wheat shoots and roots. When LMWAOs were used a good correlation was obtained between the concentrations of heavy metals in soil pools and that in wheat roots, which followed a general order of r(1 kD, LMWOAs) >r(0.2 microm, LMWOAs) approximately r(0.45 microm, LMWOAs). In the case of rare earth elements the good correlation was obtained for both the wheat roots and shoots. Generally, the correlation coefficients obtained by LMWAOs were better than that obtained by the first step of BCR method. Therefore, LMWAOs and F(lrss) were strongly recommended to predict the bioavailability of metals in soil pools to plants.

  3. Estimating and Predicting Metal Concentration Using Online Turbidity Values and Water Quality Models in Two Rivers of the Taihu Basin, Eastern China.

    Science.gov (United States)

    Yao, Hong; Zhuang, Wei; Qian, Yu; Xia, Bisheng; Yang, Yang; Qian, Xin

    2016-01-01

    Turbidity (T) has been widely used to detect the occurrence of pollutants in surface water. Using data collected from January 2013 to June 2014 at eleven sites along two rivers feeding the Taihu Basin, China, the relationship between the concentration of five metals (aluminum (Al), titanium (Ti), nickel (Ni), vanadium (V), lead (Pb)) and turbidity was investigated. Metal concentration was determined using inductively coupled plasma mass spectrometry (ICP-MS). The linear regression of metal concentration and turbidity provided a good fit, with R(2) = 0.86-0.93 for 72 data sets collected in the industrial river and R(2) = 0.60-0.85 for 60 data sets collected in the cleaner river. All the regression presented good linear relationship, leading to the conclusion that the occurrence of the five metals are directly related to suspended solids, and these metal concentration could be approximated using these regression equations. Thus, the linear regression equations were applied to estimate the metal concentration using online turbidity data from January 1 to June 30 in 2014. In the prediction, the WASP 7.5.2 (Water Quality Analysis Simulation Program) model was introduced to interpret the transport and fates of total suspended solids; in addition, metal concentration downstream of the two rivers was predicted. All the relative errors between the estimated and measured metal concentration were within 30%, and those between the predicted and measured values were within 40%. The estimation and prediction process of metals' concentration indicated that exploring the relationship between metals and turbidity values might be one effective technique for efficient estimation and prediction of metal concentration to facilitate better long-term monitoring with high temporal and spatial density.

  4. Electricite de France: Lifetime Project

    International Nuclear Information System (INIS)

    Combes, Jean-Pierre

    1991-01-01

    Electricite de France produces almost 80% of its electricity by means of standardized PWR nuclear power stations. Starting in 1986, therefore, a project known as the 'Lifetime Project' was developed, whose aim was initially to ensure that the lifetime defined at design stage (40 years in general) could be attained without major difficulty (follow up of the aging process). It then became apparent that it would be useful to know just how far it would be technically and economically possible to go. As a result, the project is now working towards increasing the lifetime of power stations. (author)

  5. Lifetimes of charmed hadrons revisited. Facts and fancy

    International Nuclear Information System (INIS)

    Blok, B.

    1994-01-01

    The problem of the hierarchy of lifetimes of charmed hadrons is reviewed. The QCD-based theory of pre asymptotic effects in inclusive weak decays dating back to the beginning of the eighties is now entering its mature phase. Combining recent and old results it is shown that the observed hierarchy reflects most intimate features of the hadronic structure. The problem of a wide spread of lifetimes of charmed hadrons is addressed. A number of predictions is given for the hierarchy of lifetimes in the family of the beautiful hadrons. (author). 29 refs., 3 figs., 1 tab

  6. Study of variables for accelerating lifetime testing of SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    Solid oxide fuel cell (SOFC) applications require lifetimes of several years on the system level. A big challenge is to proof/confirm/demonstrate such exceptionally long lifetimes.Accelerated or compressed testing are possible methods. Activities in this area have been carried out without arriving...... at different current load cycling profiles revealed a strong deviation between predicted and measured lifetime [3].In this study, we present a detailed analysis of durability results for degradation mechanisms of single SOFC components as function of operating conditions. Electrochemical impedance data...

  7. Measurement of Charm Meson Lifetimes

    International Nuclear Information System (INIS)

    Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J.; Chan, S.; Eigen, G.; Lipeles, E.; Schmidtler, M.; Shapiro, A.; Sun, W.M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Jaffe, D.E.; Masek, G.; Paar, H.P.; Potter, E.M.; Prell, S.; Sharma, V.; Asner, D.M.; Eppich, A.; Gronberg, J.; Hill, T.S.; Korte, C.M.; Lange, D.J.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Roberts, D.; Tajima, H.; Behrens, B.H.; Ford, W.T.; Gritsan, A.; Krieg, H.; Roy, J.; Smith, J.G.; Alexander, J.P.; Baker, R.; Bebek, C.; Berger, B.E.; Berkelman, K.; Boisvert, V.; Cassel, D.G.; Crowcroft, D.S.; Dickson, M.; Dombrowski, S. von; Drell, P.S.; Dumas, D.J.; Ecklund, K.M.; Ehrlich, R.; Foland, A.D.; Gaidarev, P.; Gibbons, L.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Hopman, P.I.; Katayama, N.; Kreinick, D.L.; Lee, T.; Liu, Y.; Meyer, T.O.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Thayer, J.G.; Thies, P.G.; Valant-Spaight, B.; Warburton, A.; Ward, C.; Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Rubiera, A.I.; Yelton, J.; Zheng, J.; Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Browder, T.E.; Li, Y.; Rodriguez, J.L.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D

    1999-01-01

    We report measurements of the D 0 , D + , and D + s meson lifetimes using 3.7 fb -1 of e + e - annihilation data collected near the Υ(4S) resonance with the CLEO detector. The measured lifetimes of the D 0 , D + , and D + s mesons are 408.5±4.1 +3.5 -3.4 fs , 1033.6±22.1 +9.9 -12.7 fs , and 486.3±15.0 +4.9 -5.1 fs . The precision of these lifetimes are comparable to those of the best previous measurements, and the systematic errors are very different. In a single experiment we find that the ratio of the D + s and D 0 lifetimes is 1.19±0.04 . copyright 1999 The American Physical Society

  8. Deconvolution of Positrons' Lifetime spectra

    International Nuclear Information System (INIS)

    Calderin Hidalgo, L.; Ortega Villafuerte, Y.

    1996-01-01

    In this paper, we explain the iterative method previously develop for the deconvolution of Doppler broadening spectra using the mathematical optimization theory. Also, we start the adaptation and application of this method to the deconvolution of positrons' lifetime annihilation spectra

  9. Empirical membrane lifetime model for heavy duty fuel cell systems

    Science.gov (United States)

    Macauley, Natalia; Watson, Mark; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

    2016-12-01

    Heavy duty fuel cells used in transportation system applications such as transit buses expose the fuel cell membranes to conditions that can lead to lifetime-limiting membrane failure via combined chemical and mechanical degradation. Highly durable membranes and reliable predictive models are therefore needed in order to achieve the ultimate heavy duty fuel cell lifetime target of 25,000 h. In the present work, an empirical membrane lifetime model was developed based on laboratory data from a suite of accelerated membrane durability tests. The model considers the effects of cell voltage, temperature, oxygen concentration, humidity cycling, humidity level, and platinum in the membrane using inverse power law and exponential relationships within the framework of a general log-linear Weibull life-stress statistical distribution. The obtained model is capable of extrapolating the membrane lifetime from accelerated test conditions to use level conditions during field operation. Based on typical conditions for the Whistler, British Columbia fuel cell transit bus fleet, the model predicts a stack lifetime of 17,500 h and a membrane leak initiation time of 9200 h. Validation performed with the aid of a field operated stack confirmed the initial goal of the model to predict membrane lifetime within 20% of the actual operating time.

  10. Predicting the onset of cracks in bulk metal forming by ductile damage criteria

    DEFF Research Database (Denmark)

    Christiansen, Peter; Nielsen, Chris Valentin; Martins, Paulo A.F.

    2017-01-01

    Three different ductile damage criteria, Ayada, normalized Cockcroft and Latham and a new shear stress based criterion taking into account hydrostatic tension, are utilized for predicting the onset of cracks in various deformation processes. It is found that the Ayada criterion predicts well...... the onset of cracks when they originate from hydrostatic tension. The shear based criterion predicts cracks triggered by shear and the normalized Cockcroft and Latham criterion indicates the overall area of onset of cracks caused by either hydrostatic or shear stresses. However the prediction...... is not as accurate as the Ayada criterion for cracks caused by hydrostatic tension....

  11. Predicting the stability constants of metal-ion complexes from first principles

    Czech Academy of Sciences Publication Activity Database

    Gutten, Ondrej; Rulíšek, Lubomír

    2013-01-01

    Roč. 52, č. 18 (2013), s. 10347-10355 ISSN 0020-1669 Institutional support: RVO:61388963 Keywords : stability constants * solvation energy * metal-ion complexation * theoretical calculations * DFT methods Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.794, year: 2013

  12. Hot metal temperature prediction by neural networks in the blast furnace

    International Nuclear Information System (INIS)

    Cantera, C.; Jimenez, J.; Varela, I.; Formoso, A.

    2002-01-01

    Based on a simplified model, the underlying temperature criteria is proposed as a method to study the temperature trends in a blast furnace. As an application, a neural network able to forecast hot metal temperatures from 2 to 16 h in advance (with decreasing precision) has been built. This neural network has been designed to work at real time in a production plant. (Author)

  13. Model predictions of metal speciation in freshwaters compared to measurements by in situ techniques.

    NARCIS (Netherlands)

    Unsworth, Emily R; Warnken, Kent W; Zhang, Hao; Davison, William; Black, Frank; Buffle, Jacques; Cao, Jun; Cleven, Rob; Galceran, Josep; Gunkel, Peggy; Kalis, Erwin; Kistler, David; Leeuwen, Herman P van; Martin, Michel; Noël, Stéphane; Nur, Yusuf; Odzak, Niksa; Puy, Jaume; Riemsdijk, Willem van; Sigg, Laura; Temminghoff, Erwin; Tercier-Waeber, Mary-Lou; Toepperwien, Stefanie; Town, Raewyn M; Weng, Liping; Xue, Hanbin

    2006-01-01

    Measurements of trace metal species in situ in a softwater river, a hardwater lake, and a hardwater stream were compared to the equilibrium distribution of species calculated using two models, WHAM 6, incorporating humic ion binding model VI and visual MINTEQ incorporating NICA-Donnan. Diffusive

  14. Increasing the Robustness of the Sheet Metal Forming Simulation by the Prediction of the Forming Limit Band

    Science.gov (United States)

    Banabic, D.; Vos, M.; Paraianu, L.; Jurco, P.

    2007-05-01

    The experimental research on the formability of metal sheets has shown that there is a significant dispersion of the limit strains in an area delimited by two curves: a lower curve (LFLC) and an upper one (UFLC). The region between the two curves defines the so-called Forming Limit Band (FLB). So far, this forming band has only been determined experimentally. In this paper the authors suggested a method to predict the Forming Limit Band. The proposed method is illustrated on the AA6111-T43 aluminium alloy.

  15. Increasing the Robustness of the Sheet Metal Forming Simulation by the Prediction of the Forming Limit Band

    International Nuclear Information System (INIS)

    Banabic, D.; Paraianu, L.; Vos, M.; Jurco, P.

    2007-01-01

    The experimental research on the formability of metal sheets has shown that there is a significant dispersion of the limit strains in an area delimited by two curves: a lower curve (LFLC) and an upper one (UFLC). The region between the two curves defines the so-called Forming Limit Band (FLB). So far, this forming band has only been determined experimentally. In this paper the authors suggested a method to predict the Forming Limit Band. The proposed method is illustrated on the AA6111-T43 aluminium alloy

  16. Optimal descriptor as a translator of eclectic data into prediction of cytotoxicity for metal oxide nanoparticles under different conditions.

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A; Rallo, Robert; Leszczynska, Danuta; Leszczynski, Jerzy

    2015-02-01

    The Monte Carlo technique has been used to build up quantitative structure-activity relationships (QSARs) for prediction of dark cytotoxicity and photo-induced cytotoxicity of metal oxide nanoparticles to bacteria Escherichia coli (minus logarithm of lethal concentration for 50% bacteria pLC50, LC50 in mol/L). The representation of nanoparticles include (i) in the case of the dark cytotoxicity a simplified molecular input-line entry system (SMILES), and (ii) in the case of photo-induced cytotoxicity a SMILES plus symbol '^'. The predictability of the approach is checked up with six random distributions of available data into the visible training and calibration sets, and invisible validation set. The statistical characteristics of these models are correlation coefficient 0.90-0.94 (training set) and 0.73-0.98 (validation set). Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Lifetime modelling of lead acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bindner, H.; Cronin, T.; Lundsager, P.

    2005-04-01

    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 research project (ENK6-CT-2001-80576), funded by the European Union, the United States and Australian governments together with other European states and other public and private financing bodies. The project has concentrated on lead acid batteries as this technology is the most commonly used. Through this work the project partner institutions have intended to provide useful tools to improve the design capabilities of organizations, private and public, in remote power systems. (au)

  18. Hot metal temperature prediction and simulation by fuzzy logic in a blast furnace

    International Nuclear Information System (INIS)

    Romero, M. A.; Jimenez, J.; Mochon, J.; Formoso, A.; Bueno, F.; Menendez, J. L.

    2000-01-01

    This work describes the development and further validation of a model devoted to blast furnace hot metal temperature forecast, based on Fuzzy logic principles. The model employs as input variables, the control variables of an actual blast furnace: Blast volume, moisture, coal injection, oxygen addition, etc. and it yields as a result the hot metal temperature with a forecast horizon of forty minutes. As far as the variables used to develop the model have been obtained from data supplied by an actual blast furnaces sensors, it is necessary to properly analyse and handle such data. Especial attention was paid to data temporal correlation, fitting by interpolation the different sampling rates. In the training stage of the model the ANFIS (Adaptive Neuro-Fuzzy Inference System) and the Subtractive Clustering algorithms have been used. (Author) 9 refs

  19. Comparison of methods for calculating decay lifetimes

    International Nuclear Information System (INIS)

    Tobocman, W.

    1978-01-01

    A simple scattering model is used to test alternative methods for calculating decay lifetimes, or equivalently, resonance widths. We consider the scattering of s-wave particles by a square well with a square barrier. Exact values for resonance energies and resonance widths are compared with values calculated from Wigner-Weisskopf perturbation theory and from the Garside-MacDonald projection operator formalism. The Garside-MacDonald formalism gives essentially exact results while the predictions of the Wigner-Weisskopf formalism are fairly poor

  20. Stress analysis and deformation prediction of sheet metal workpieces based on finite element simulation

    OpenAIRE

    Ren Penghao; Wang Aimin; Wang Xiaolong; Zhang Yanlin

    2017-01-01

    After aluminum alloy sheet metal parts machining, the residual stress release will cause a large deformation. To solve this problem, this paper takes a aluminum alloy sheet aerospace workpiece as an example, establishes the theoretical model of elastic deformation and the finite element model, and places quantitative initial stress in each element of machining area, analyses stress release simulation and deformation. Through different initial stress release simulative analysis of deformation ...

  1. Are persistent organic pollutants and metals in eel muscle predictive for the ecological water quality?

    International Nuclear Information System (INIS)

    Van Ael, Evy; Belpaire, Claude; Breine, Jan; Geeraerts, Caroline; Van Thuyne, Gerlinde; Eulaers, Igor; Blust, Ronny; Bervoets, Lieven

    2014-01-01

    Relationships between the presence of PCBs, OCPs and metals in aquatic ecosystems and the ecological water quality were investigated by combining datasets of long-term monitoring of chemicals in European eel (Anguilla anguilla, N = 1156) in Flanders (Belgium) and the Ecological Quality Ratio (EQR), based on the assessment of fish assemblages at 185 locations. For most pollutants, EQR scores were lower when pollutant levels were higher. Threshold concentrations for a good quality could be formulated for PCB's, most metals and OCPs. Mixed models suggested that the ecological water quality was significantly correlated with the presence of PCBs. However, the low R 2 indicates that other environmental pressures may significantly influence the biotic integrity of fish communities. Empirical data and their analyses are essential to enable defining threshold values of bioaccumulated levels to allow better protection of the aquatic environment and its biota through associated food webs as demanded by the Water Framework Directive. -- Highlights: • Relation between ecological water quality and pollution load in eel was studied. • Ecological Quality Ratio was lower when concentrations in eel were higher. • Threshold levels for a good quality status were formulated. • EQS possibly too stringent for Hg and too high for Cd and Pb compared to our results. • Mixed models suggest a significant influence of PCBs on ecological water quality. -- The ecological water quality, as reflected in the biotic integrity of fish communities, is lower when concentrations of PCBs, OCPs and metals in locally sampled eels are higher

  2. A CFD-Model for prediction of unintended porosities in metal matrix composites

    DEFF Research Database (Denmark)

    Li, Shizhao; Spangenberg, Jon; Hattel, Jesper Henri

    2013-01-01

    This paper presents a numerical method that simulates the flow through the porous corridors of the preform, which in theory enables the prediction of unintended porosities at the end of the process....

  3. The Prediction of Metal Slopping in LD Converter on Base an Acoustic Signal

    Directory of Open Access Journals (Sweden)

    Kostúr, K.

    2006-01-01

    Full Text Available The negative influences of slopping in a BOF are pollution to the environment. They give lower yield and cause equipment damage. The prediction of these phenomena is based on information processing from the measuring microphone. The change of frequency in certain range is done by a signal for the prediction of slopping. In this paper two methods for prediction of slopping are described. The first method is based on measuring and processing of sound emitted from the vessel during the blow. The second method utilizes Fourier’s transformation for processing of acoustic signal from sonic meter. The success rate of prediction has been evaluated by help of five criterions. It is possible to forecast the slopping on selected frequency (band. It is the essence of the second method, because this method has high success (criterion K1. Note, that criterion K5 defines acknowledgment of duration slopping. This criterion has the highest value.

  4. Prediction of material damage in orthotropic metals for virtual structural testing

    OpenAIRE

    Ravindran, S.

    2010-01-01

    Models based on the Continuum Damage Mechanics principle are increasingly used for predicting the initiation and growth of damage in materials. The growing reliance on 3-D finite element (FE) virtual structural testing demands implementation and validation of robust material models that can predict the material behaviour accurately. The use of these models within numerical analyses requires suitable material data. EU aerospace companies along with Cranfield University and other similar resear...

  5. Occupational risk and lifetime exposure

    International Nuclear Information System (INIS)

    Lapp, R.E.

    1991-01-01

    Any lowering of annual radiation limits for occupational exposure should be based on industry experience with lifetime doses and not on a worst case career exposure of 47 years. Two decades of experience show a lifetime accumulation of less than 1.5 rem for workers with measurable exposure. This is 5% of the normal lifetime exposure of Americans to natural and medical radiation. Any epidemiology of the US nuclear power workforce's two decade long exposure would have to focus on excess leukemia. Application of the Hiroshima and Nagasaki cancer mortality shows that too few leukemias would be expressed to permit a feasible epidemiology. Ionizing radiation appears to be a mild carcinogen as compared to physical and chemical agents presented in the occupational environment. A realistic factor in determining any change in occupational exposure limits for ionizing radiation should take into account the past performance of the licensee and potential health effects applicable to the workplace. Specifically, the lifetime exposure data for workers at nuclear power plants and naval shipyards should be considered. The nuclear industry and the US Navy have detailed data on the annual exposure of workers with a combined collective exposure approaching 1 million worker-rem. The lifetime dose for naval personnel and shipyard workers averages 1.1 rem J 1990. Shipyard workers have an annual dose of 0.28 rem per work-year and a mean exposure time of 4.4 years. The data apply to workers with measurable dose

  6. Predicting criteria continuous concentrations of 34 metals or metalloids by use of quantitative ion character-activity relationships–species sensitivity distributions (QICAR–SSD) model

    International Nuclear Information System (INIS)

    Mu, Yunsong; Wu, Fengchang; Chen, Cheng; Liu, Yuedan; Zhao, Xiaoli; Haiqing Liao; Giesy, John P.

    2014-01-01

    Criteria continuous concentrations (CCCs) are useful for describing chronic exposure to pollutants and setting water quality standards to protect aquatic life. However, because of financial, practical, or ethical restrictions on toxicity testing, few data are available to derive CCCs. In this study, CCCs for 34 metals or metalloids were derived using quantitative ion character-activity relationships–species sensitivity distributions (QICAR–SSD) and the final acute-chronic ratio (FACR) method. The results showed that chronic toxic potencies were correlated with several physico-chemical properties among eight species chosen, where the softness index was the most predictive characteristic. Predicted CCCs for most of the metals, except for Lead and Iron, were within a range of 10-fold of values recommended by the U.S. EPA. The QICAR–SSD model was superior to the FACR method for prediction of data-poor metals. This would have significance for predicting toxic potencies and criteria thresholds of more metals or metalloids. - Highlights: • We investigate relationships between σp and log-NOEC in eight species. • The QICAR–SSD model, FACR, and CMC/CCC were used to predict CCCs. • They are as a supplement to screening for toxicities, criteria and standards. - CCCs for 34 metals/metalloids were predicted by use of QICAR–SSD model and FACR method

  7. Effect of Junction Temperature Swing Durations on a Lifetime of a Transfer Molded IGBT Module

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Jorgensen, Soren

    2016-01-01

    results under 6 different conditions and it may improve a lifetime model for lifetime prediction of IGBT modules under various mission profiles of converters. The power cycling tests are performed by an advanced power cycling test setup which enables tested modules to be operated under more realistic......In this paper, the effect of junction temperature swing duration on the lifetime of a transfer molded Intelligent Power IGBT Module is studied and a relevant lifetime factor is modeled. A temperature swing duration dependent lifetime factor is defined based on 38 accelerated power cycling test...

  8. Study on Effect of Junction Temperature Swing Duration on Lifetime of Transfer Molded Power IGBT Modules

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Jørgensen, Søren

    2017-01-01

    levels are presented. This study enables to include the tΔTj effect on lifetime model of IGBT modules for its lifetime estimation and it may result in improved lifetime prediction of IGBT modules under given mission profiles of converters. A postfailure analysis of the tested IGBT modules is also......In this paper, the effect of junction temperature swing duration on lifetime of transfer molded power insulated gate bipolar transistor (IGBT) modules is studied and a relevant lifetime factor is modeled. This study is based on 39 accelerated power cycling test results under six different...

  9. Troubles in the systematic prediction of transition metal thermochemistry with contemporary out-of-the-box methods

    KAUST Repository

    Minenkov, Yury

    2016-03-22

    The recently developed DLPNO-CCSD(T) method and 7 popular DFT functionals (B3LYP, M06, M06L, PBE, PBE0, TPSS and TPSSh) with and without an empirical dispersion term have been tested to reproduce 111 gas phase reaction enthalpies involving 11 different transition metals. Our calculations, corrected for both relativistic effects and basis set incompleteness, indicate that most of the methods applied with default settings perform with acceptable accuracy on average. Nevertheless, our calculations also evidenced unexpected and non systematic large deviations for specific cases. For group 12 metals (Zn, Cd, Hg) most of the methods provided mean unsigned errors (MUE) less than 5.0 kcal/mol, with DLPNO-CCSD(T) and PBE methods performing excellently (MUE lower 2.0 kcal/mol). Problems started with group 4 metals (Ti and Zr). Best performer for Zr complexes with a MUE of 1.8 kcal/mol, PBE0-D3, provides a MUE larger than 8 kcal/mol for Ti. DLPNO-CCSD(T) provides a reasonable MUE of 3.3 kcal/mol for Ti reactions, but gives MUE a larger than 14.4 kcal/mol for Zr complexes, with all the larger deviations for reactions involving ZrF4. Large and non-systematic errors have been obtained for group 6 metals (Mo and W), for 8 reactions containing Fe, Cu, Nb and Re complexes. Finally, for the whole set of 111 reactions, the DLPNO-CCSD(T), B3LYP-D3 and PBE0-D3 methods turned out to be the best performers, both providing MUE below 5.0 kcal/mol. Since DFT results cannot be systematically improved and large non-systematic deviations of 20-30 kcal/mol were obtained even for best performers, our results indicates that current DFT methods are still unable to provide robust predictions in transition metal thermochemistry, at least for the functionals explored in this work. The same conclusion holds for both DLPNO-CCSD(T) and canonical CCSD(T) methods when used entirely as out-of-the-box. However if careful investigation core correlation is performed, relativistic effects are properly included

  10. Lifetime suicide attempts in juvenile assessment center youth.

    Science.gov (United States)

    Nolen, Scott; McReynolds, Larkin S; DeComo, Robert E; John, Reni; Keating, Joseph M; Wasserman, Gail A

    2008-01-01

    To describe suicide risk in youth seen at a Juvenile Assessment Center (JAC), we examined relationships among self-reported lifetime attempts and demographic, justice, and psychiatric data via logistic regression. Similar to other settings, youth reporting lifetime attempts were more likely to be older, female, not living with both parents and currently arrested for a violent or felony crime. Mood, substance use, and behavior disorder each increased prediction substantially. Anxiety Disorder was associated with elevated attempt rates for boys only. JACs need to develop protocols for identifying suicide risk; further, since suicide history predicts future attempts, Anxiety Disordered boys may be at particular risk.

  11. THE LIFETIME EXTENSION OF CAR AXLES TYPES OF RU1 AND RUSH WHEELSET FREIGHT CARS, RESTORED BY THE METHOD OF PLASMA-ARC METALLIZATION OF THE NECK AND UNDER PARTS MANUAL

    Directory of Open Access Journals (Sweden)

    V. I. Zelenin

    2009-03-01

    Full Text Available The restoration method for the journals and wheel seats of the freight wagon wheelsets by means of plasma-arc metallization is presented and the results of the bench fatigue tests with the advisable operation life of the axles restored are given.

  12. GRSIS program to predict fission gas release and swelling behavior of metallic fast reactor fuel

    International Nuclear Information System (INIS)

    Lee, Chan Bock; Lee, Byung Ho; Nam, Cheol; Sohn, Dong Seong

    1999-03-01

    A mechanistic model of fission gas release and swelling for the U-(Pu)-Zr metallic fuel in the fast reactor, GRSIS (Gas Release and Swelling in ISotropic fuel matrix) was developed. Fission gas bubbles are assumed to nucleate isotropically from the gas atoms in the metallic fuel matrix since they can nucleate at both the grain boundaries and the phase boundaries which are randomly distributed inside the grain. Bubbles can grow to larger size by gas diffusion and coalition with other bubbles so that they are classified as three classes depending upon their sizes. When bubble swelling reaches the threshold value, bubbles become interconnected each other to make the open channel to the external free space, that is, the open bubbles and then fission gases inside the interconnected open bubbles are released instantaneously. During the irradiation, fission gases are released through the open bubbles. GRSIS model can take into account the fuel gap closure by fuel bubble swelling. When the fuel gap is closed by fuel swelling, the contact pressure between fuel and cladding in relation to the bubble swelling and temperature is calculated. GRSIS model was validated by comparison with the irradiation test results of U-(Pu)-Zr fuels in ANL as well as the parametric studies of the key variable in the model. (author). 13 refs., 1 tab., 22 figs

  13. GRSIS program to predict fission gas release and swelling behavior of metallic fast reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chan Bock; Lee, Byung Ho; Nam, Cheol; Sohn, Dong Seong

    1999-03-01

    A mechanistic model of fission gas release and swelling for the U-(Pu)-Zr metallic fuel in the fast reactor, GRSIS (Gas Release and Swelling in ISotropic fuel matrix) was developed. Fission gas bubbles are assumed to nucleate isotropically from the gas atoms in the metallic fuel matrix since they can nucleate at both the grain boundaries and the phase boundaries which are randomly distributed inside the grain. Bubbles can grow to larger size by gas diffusion and coalition with other bubbles so that they are classified as three classes depending upon their sizes. When bubble swelling reaches the threshold value, bubbles become interconnected each other to make the open channel to the external free space, that is, the open bubbles and then fission gases inside the interconnected open bubbles are released instantaneously. During the irradiation, fission gases are released through the open bubbles. GRSIS model can take into account the fuel gap closure by fuel bubble swelling. When the fuel gap is closed by fuel swelling, the contact pressure between fuel and cladding in relation to the bubble swelling and temperature is calculated. GRSIS model was validated by comparison with the irradiation test results of U-(Pu)-Zr fuels in ANL as well as the parametric studies of the key variable in the model. (author). 13 refs., 1 tab., 22 figs.

  14. Observing the metal-poor solar neighbourhood: a comparison of galactic chemical evolution predictions*†

    Science.gov (United States)

    Mishenina, T.; Pignatari, M.; Côté, B.; Thielemann, F.-K.; Soubiran, C.; Basak, N.; Gorbaneva, T.; Korotin, S. A.; Kovtyukh, V. V.; Wehmeyer, B.; Bisterzo, S.; Travaglio, C.; Gibson, B. K.; Jordan, C.; Paul, A.; Ritter, C.; Herwig, F.; NuGrid Collaboration

    2017-08-01

    Atmospheric parameters and chemical compositions for 10 stars with metallicities in the region of -2.2 LTE) and non-LTE (NLTE) approaches. In particular, differences by assuming LTE or NLTE are about 0.10 dex; depending on [Fe/H], Teff, gravity and element lines used in the analysis. We find that the O abundance has the largest error, ranging from 0.10 and 0.2 dex. The best measured elements are Cr, Fe, and Mn; with errors between 0.03 and 0.11 dex. The stars in our sample were included in previous different observational work. We provide a consistent data analysis. The data dispersion introduced in the literature by different techniques and assumptions used by the different authors is within the observational errors, excepting for HD103095. We compare these results with stellar observations from different data sets and a number of theoretical galactic chemical evolution (GCE) simulations. We find a large scatter in the GCE results, used to study the origin of the elements. Within this scatter as found in previous GCE simulations, we cannot reproduce the evolution of the elemental ratios [Sc/Fe], [Ti/Fe], and [V/Fe] at different metallicities. The stellar yields from core-collapse supernovae are likely primarily responsible for this discrepancy. Possible solutions and open problems are discussed.

  15. Management of nuclear power plants lifetime

    International Nuclear Information System (INIS)

    Hutin, J.P.

    2006-01-01

    The factors influencing the management of the service life of nuclear power plants can be of various types and the 'heaviest' ones have to be managed through robust and explicit approaches involving all actors. However, the mastery of the service life starts with the mastery of the technical problems, in particular the physical aging of the facilities. This mastery requires to foresee and anticipate the problems and thus a good understanding of the phenomena involved. This article presents: 1 - the general problem of service life management: lifetime concept, situation of French power plants, service life management policy; 2 - aging mechanisms: embrittlement of steel under irradiation, swelling of materials, thermal aging, fatigue, stress corrosion, aqueous corrosion of metals, corrosion-erosion, mechanisms of concrete degradation, mechanisms of elastomers and polymers degradation, wear; 3 - non-replaceable parts: reactor vessel, containment building; 4 - replaceable parts: cables, instrumentation and control system, core internals, primary loop piping, auxiliary primary piping, pressurizer, primary pump, steam generator tubes, other Ni-Cr-Fe alloy parts, secondary loop piping, turbine, alternator; 5 - non-technical aspects: perenniality of the industrial support, evolution of safety requirements, public acceptance, economical aspects, knowledge and information systems; 6 - situation in foreign countries: status of the world nuclear park, lifetime notion in foreign countries, situation in the USA. (J.S.)

  16. Lifetime results from heavy quark systems

    International Nuclear Information System (INIS)

    Papadimitriou, V.

    1997-11-01

    We present the latest measurements of weakly decaying b-hadrons from experiments at e + e - and p anti p colliders. These measurements include the average lifetime of b-hadrons, lifetimes of the B - , B 0 and B 0 s mesons, the average lifetime of b-baryons and lifetimes of the Λ b and Ξ b baryons

  17. Analytical prediction model for non-symmetric fatigue crack growth in Fibre Metal Laminates

    NARCIS (Netherlands)

    Wang, W.; Rans, C.D.; Benedictus, R.

    2017-01-01

    This paper proposes an analytical model for predicting the non-symmetric crack growth and accompanying delamination growth in FMLs. The general approach of this model applies Linear Elastic Fracture Mechanics, the principle of superposition, and displacement compatibility based on the

  18. Prediction of metal wastage produced by sodium-water reaction jets

    International Nuclear Information System (INIS)

    Payne, J.F.B.

    1979-01-01

    When a leak occurs in a sodium heated boiler, a sodium-water reaction jet is formed which causes further damage to the boiler, ie wastage. A correlation is developed which predicts wastage of ferritic steel boiler tubes for the range of leak sizes, sodium temperatures and leak to target spacing for which data available. (author)

  19. Validation of Transfer Functions Predicting Cd and Pb Free Metal Ion Activity in Soil Solution as a Function of Soil Characteristics and Reactive Metal Content

    NARCIS (Netherlands)

    Pampura, T.; Groenenberg, J.E.; Lofts, S.; Priputina, I.

    2007-01-01

    According to recent insight, the toxicity of metals in soils is better related to the free metal ion (FMI) activity in the soil solution than to the total metal concentration in soil. However, the determination of FMI activities in soil solution is a difficult and time-consuming task. An alternative

  20. Theoretical prediction of Grüneisen parameter for SiO_2.TiO_2 bulk metallic glasses

    International Nuclear Information System (INIS)

    Singh, Chandra K.; Pandey, Brijesh K.; Pandey, Anjani K.

    2016-01-01

    The Grüneisen parameter (γ) is very important to decide the limitations for the prediction of thermoelastic properties of bulk metallic glasses. It can be defined in terms of microscopic and macroscopic parameters of the material in which former is based on vibrational frequencies of atoms in the material while later is closely related to its thermodynamic properties. Different formulation and equation of states are used by the pioneer researchers of this field to predict the true sense of Gruneisen parameter for BMG but for SiO_2.TiO_2 very few and insufficient information is available till now. In the present work we have tested the validity of two different isothermal EOS viz. Poirrior-Tarantola EOS and Usual-Tait EOS to predict the true value of Gruneisen parameter for SiO_2.TiO_2 as a function of compression. Using different thermodynamic limitations related to the material constraints and analyzing obtained result it is concluded that the Poirrior-Tarantola EOS gives better numeric values of Grüneisen parameter (γ) for SiO_2.TiO_2 BMG.

  1. Determining the residual lifetime for the main RBMK components in frame of life extension of power units

    International Nuclear Information System (INIS)

    Baldin, V.D.; Petrov, A.A.; Potapov, A.A.

    2005-01-01

    At present time 11 power units of NPPs with RBMK reactors produce annually 140 billion kWh of electricity, which is about half of all electricity generated at Russian NPPs. Commissioned during the period of 1973 to 1990, they have the specified service life of 30 years. The power units have been regularly upgraded during operation to raise their safety and reliability. As the result now they meet modem requirements in terms of safety and their lifetime can considerably exceed their specified service life. The task of the plant life extension becomes more urgent. The main nonreplaceable RBMK reactor components that determine the reactor life, are graphite stack and metal support structures. The aging of these structures is monitored and the structures residual lifetime is predicted in accordance with procedures approved by regulatory authorities. The lead unit among all RBMK power units is Leningrad NPP Unit 1 commissioned in 1973. A complex of activities was performed for this power unit in 2002-2003 to prove the feasibility of its life extension. In terms of defining the residual lifetime of the reactor components, the activities were performed in three major areas: - examination of the state of the reactor structures; - materials studies of irradiated metal and graphite specimens in hot chambers; - performing the calculation and prediction evaluations. The results of examining the metal structures and studying specimens have shown that: 1)The metal and the welds do not have visible defects. The state of protective coatings is largely satisfactory. 2)The ultimate strength and hardness of steel have grown. 3)The brittle fracture transition temperature shift is at the allowable level. 4)The leak-tightness of the metal structures has not been violated. The results of the graphite stack examination have shown that the graphite is at the hardening stage. No tendency for deterioration of mechanical properties has been recorded. According to the results of measuring the

  2. Testing and Prediction of Limits of Lubrication in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Bay, Niels

    2012-01-01

    Increasing focus on environmental issues in industrial production has urged a number of sheet metal forming companies to look for new tribo-systems, here meaning the combination of tool_material/workpiece_material/lubricant, in order to substitute hazardous lubricants such as chlorinated paraffin...... laboratory and production tests as well as numerical analyses in order to evaluate and compare performance of the new tribo-systems. A part is selected from industrial production and analyzed by this methodology in order to substitute the existing tribo-system with a new one....... oils. Testing of new tribo-systems under production conditions is, however, very costly. For preliminary testing it is more feasible to introduce laboratory tests. In this paper a new methodology for testing new tribo-systems is presented. The methodology describes a series of investigations combining...

  3. Stress analysis and deformation prediction of sheet metal workpieces based on finite element simulation

    Directory of Open Access Journals (Sweden)

    Ren Penghao

    2017-01-01

    Full Text Available After aluminum alloy sheet metal parts machining, the residual stress release will cause a large deformation. To solve this problem, this paper takes a aluminum alloy sheet aerospace workpiece as an example, establishes the theoretical model of elastic deformation and the finite element model, and places quantitative initial stress in each element of machining area, analyses stress release simulation and deformation. Through different initial stress release simulative analysis of deformation of the workpiece, a linear relationship between initial stress and deformation is found; Through simulative analysis of coupling direction-stress release, the superposing relationship between the deformation caused by coupling direction-stress and the deformation caused by single direction stress is found. The research results provide important theoretical support for the stress threshold setting and deformation controlling of the workpieces in the production practice.

  4. Lifetime value in business process

    Directory of Open Access Journals (Sweden)

    Martin Souček

    2011-01-01

    Full Text Available The paper focuses on lifetime value assessment and its implementation and application in business processes. The lifetime value is closely connected to customer relationship management. The paper presents results of three consecutive researches devoted to issues of customer relationship management. The first two from 2008 and 2010 were conducted as quantitative ones; the one from 2009 had qualitative nature. The respondents were representatives of particular companies. The means for data collection was provided by ReLa system. We will focus on individual attributes of lifetime value of a customer, and relate them to approaches of authors mentioned in introduction. Based on the qualitative research data, the paper focuses on individual customer lifetime value parameters. These parameters include: the cost to the customer relationship acquisition and maintenance, profit generated from a particular customer, customer awareness value, the level of preparedness to adopt new products, the value of references and customer loyalty level. For each of these parameters, the paper provides specific recommendations. Moreover, it is possible to learn about the nature of these parameter assessments in the Czech environment.

  5. Lifetime of heavy flavour particles

    International Nuclear Information System (INIS)

    Lueth, V.

    1985-10-01

    Recent measurements of the lifetime of the tau leptons and charm and beauty hadrons are reviewed and their significance for the couplings of the charged weak current, flavour mixing, and models relating quarks to hadron decay are discussed. 70 refs., 17 figs., 5 tabs

  6. Benchmarking of Touschek Beam Lifetime Calculations for the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, A.; Yang, B.

    2017-06-25

    Particle loss from Touschek scattering is one of the most significant issues faced by present and future synchrotron light source storage rings. For example, the predicted, Touschek-dominated beam lifetime for the Advanced Photon Source (APS) Upgrade lattice in 48-bunch, 200-mA timing mode is only ~ 2 h. In order to understand the reliability of the predicted lifetime, a series of measurements with various beam parameters was performed on the present APS storage ring. This paper first describes the entire process of beam lifetime measurement, then compares measured lifetime with the calculated one by applying the measured beam parameters. The results show very good agreement.

  7. Positron lifetime measurements on electron irradiated amorphous alloys

    International Nuclear Information System (INIS)

    Moser, P.; Hautojaervi, P.; Chamberod, A.; Yli-Kauppila, J.; Van Zurk, R.

    1981-08-01

    Great advance in understanding the nature of point defects in crystalline metals has been achieved by employing positron annihilation technique. Positrons detect vacancy-type defects and the lifetime value of trapped positrons gives information on the size of submicroscopic vacancy aglomerates and microvoids. In this paper it is shown that low-temperature electron irradiations can result in a considerable increase in the positron lifetimes in various amorphous alloys because of the formation of vacancy-like defects which, in addition of the pre-existing holes, are able to trap positrons. Studied amorphous alloys were Fe 80 B 20 , Pd 80 Si 20 , Cu 50 Ti 50 , and Fe 40 Ni 40 P 14 B 6 . Electron irradiations were performed with 3 MeV electrons at 20 K to doses around 10 19 e - /cm 2 . After annealing positron lifetime spectra were measured at 77 K

  8. 3D transient model to predict temperature and ablated areas during laser processing of metallic surfaces

    Directory of Open Access Journals (Sweden)

    Babak. B. Naghshine

    2017-02-01

    Full Text Available Laser processing is one of the most popular small-scale patterning methods and has many applications in semiconductor device fabrication and biomedical engineering. Numerical modelling of this process can be used for better understanding of the process, optimization, and predicting the quality of the final product. An accurate 3D model is presented here for short laser pulses that can predict the ablation depth and temperature distribution on any section of the material in a minimal amount of time. In this transient model, variations of thermal properties, plasma shielding, and phase change are considered. Ablation depth was measured using a 3D optical profiler. Calculated depths are in good agreement with measured values on laser treated titanium surfaces. The proposed model can be applied to a wide range of materials and laser systems.

  9. Predicting intragranular misorientation distributions in polycrystalline metals using the viscoplastic self-consistent formulation

    DEFF Research Database (Denmark)

    Zecevic, Miroslav; Pantleon, Wolfgang; Lebensohn, Ricardo A.

    2017-01-01

    In a recent paper, we reported the methodology to calculate intragranular fluctuations in the instantaneous lattice rotation rates in polycrystalline materials within the mean-field viscoplastic self-consistent (VPSC) model. This paper is concerned with the time integration and subsequent use......, we calculate intragranular misorientations in face-centered cubic polycrystals deformed in tension and plane-strain compression. These predictions are tested by comparison with corresponding experiments for polycrystalline copper and aluminum, respectively, and with full-field calculations....... It is observed that at sufficiently high strains some grains develop large misorientations that may lead to grain fragmentation and/or act as driving forces for recrystallization. The proposed VPSC-based prediction of intragranular misorientations enables modeling of grain fragmentation, as well as a more...

  10. Predicting wettability behavior of fluorosilica coated metal surface using optimum neural network

    Science.gov (United States)

    Taghipour-Gorjikolaie, Mehran; Valipour Motlagh, Naser

    2018-02-01

    The interaction between variables, which are effective on the surface wettability, is very complex to predict the contact angles and sliding angles of liquid drops. In this paper, in order to solve this complexity, artificial neural network was used to develop reliable models for predicting the angles of liquid drops. Experimental data are divided into training data and testing data. By using training data and feed forward structure for the neural network and using particle swarm optimization for training the neural network based models, the optimum models were developed. The obtained results showed that regression index for the proposed models for the contact angles and sliding angles are 0.9874 and 0.9920, respectively. As it can be seen, these values are close to unit and it means the reliable performance of the models. Also, it can be inferred from the results that the proposed model have more reliable performance than multi-layer perceptron and radial basis function based models.

  11. Prediction and prevention of rockburst in metal mines – A case study of Sanshandao gold mine

    Directory of Open Access Journals (Sweden)

    Meifeng Cai

    2016-04-01

    Full Text Available Rockburst is a kind of artificial earthquake induced by human activities, such as mining excavations. The mechanism of rockburst induced by mining disturbance is revealed in terms of energy in this context. For understanding the rockburst mechanism, two necessary conditions for the occurrence of rockburst are presented: (1 the rock mass has the capability to store huge amount of energy and possesses a strong bumping-prone characteristic when damaged; and (2 the geological conditions in the mining area have favorable geo-stress environments that can form high-stress concentration area and accumulate huge energy. These two conditions are also the basic criteria for prediction of rockburst. In view of energy analysis, it is observed that artificial and natural earthquakes have similar regularities in many aspects, such as the relationship between the energy value and burst magnitude. By using the relationship between energy and magnitude of natural earthquake, rockburst is predicted by disturbance energy analysis. A practical example is illustrated using the above-mentioned theorem and technique to predict rockburst in a gold mine in China. Finally, the prevention and control techniques of rockburst are also provided based on the knowledge of the rockburst mechanism.

  12. Prediction of total dose effects on sub-micron process metal oxide semiconductor devices

    International Nuclear Information System (INIS)

    Kamimura, Hiroshi; Kato, Masataka.

    1991-01-01

    A method for correcting leakage currents is described to predict the radiation-induced threshold voltage shift of sub-micron MOSFETs. A practical model for predicting the leakage current generated by irradiation is also given on the basis of experimental results on 0.8-μm process MOSFETs. The constants in the threshold voltage shift model are determined from the 'true' I-V characteristic of the MOSFET, which is obtained by correction of leakage currents due to characteristic change of a parasitic transistor. In this way, the threshold voltage shift of the n-channel MOSFET irradiated at a low dose rate of 2 Gy(Si)/h was also calculated by using data from a high dose rate irradiation experiment (100 Gy(Si)/h, 5 h). The calculated result well represented the tendency of measured data on threshold voltage shift. The radiation-induced leakage current was considered to decay approximately in two exponential modes. The constants in this leakage current model were determined from the above high dose rate experiment. The response of leakage current predicted at a low dose rate of 2 Gy(Si)/h approximately agreed with that measured during and after irradiation. (author)

  13. Heritability of lifetime ecstasy use.

    Science.gov (United States)

    Verweij, Karin J H; Treur, Jorien L; Vreeker, Annabel; Brunt, Tibor M; Willemsen, Gonneke; Boomsma, Dorret I; Vink, Jacqueline M

    2017-09-01

    Ecstasy is a widely used psychoactive drug that users often take because they experience positive effects such as increased euphoria, sociability, elevated mood, and heightened sensations. Ecstasy use is not harmless and several immediate and long term side effects have been identified. Lifetime ecstasy use is likely to be partly influenced by genetic factors, but no twin study has determined the heritability. Here, we apply a classical twin design to a large sample of twins and siblings to estimate the heritability of lifetime ecstasy use. The sample comprised 8500 twins and siblings aged between 18 and 45 years from 5402 families registered at the Netherlands Twin Registry. In 2013-2014 participants filled out a questionnaire including a question whether they had ever used ecstasy. We used the classical twin design to partition the individual differences in liability to ecstasy use into that due to genetic, shared environmental, and residual components. Overall, 10.4% of the sample had used ecstasy during their lifetime, with a somewhat higher prevalence in males than females. Twin modelling indicated that individual differences in liability to lifetime ecstasy use are for 74% due to genetic differences between individuals, whereas shared environmental and residual factors explain a small proportion of its liability (5% and 21%, respectively). Although heritability estimates appeared to be higher for females than males, this difference was not significant. Lifetime ecstasy use is a highly heritable trait, which indicates that some people are genetically more vulnerable to start using ecstasy than others. Copyright © 2017. Published by Elsevier B.V.

  14. Prediction of liquid metal alloy radiant properties from measurements of the Hall coefficient and the direct current resistivity

    International Nuclear Information System (INIS)

    Havstad, M.A.; Qiu, T.

    1995-04-01

    The thermal radiative properties of high temperature solid and liquid metal alloys are particularly useful to research and development efforts in laser cladding and machining, electron beam welding and laser isotope separation. However the cost, complexity, and difficulty of measuring these properties have forced the use of crude estimates from the Hagen-Rubens relation, the Drude relations, or extrapolation from low temperature or otherwise flawed data (e.g., oxidized). The authors have found in this work that published values for the Hall coefficient and the electrical resistivity of liquid metal alloys can provide useful estimates of the reflectance and emittance of some groups of binary liquid metal and high temperature solid alloys. The estimation method computes the Drude free electron parameters, and thence the optical constants and the radiant properties from the dependence of the Hall coefficient and direct current resistivity on alloy composition (the Hall coefficient gives the free electron density and the resistivity gives the average time between collisions). They find that predictions of the radiant properties of molten cerium-copper alloy, which use the measured variations in the Hall coefficient and resistivity (both highly nonlinear) as a function of alloy fraction (rather than linear combinations of the values of the pure elements) yield a good comparison to published measurements of the variation of the normal spectral emittance (a different but also nonlinear function) of cerium-copper alloy at the single wavelength available for comparison, 0.645 μm. The success of the approach in the visible range is particularly notable because one expects a Drude based approach to improve with increasing wavelength from the visible into the infrared. Details of the estimation method, the comparison between the calculation and the measured emittance, and a discussion of what groups of elements may also provide agreement is given

  15. Half-metallic ferromagnetism prediction in MoS2-based two-dimensional superlattice from first-principles

    Science.gov (United States)

    Wen, Yan-Ni; Gao, Peng-Fei; Xia, Ming-Gang; Zhang, Sheng-Li

    2018-03-01

    Half-metallic ferromagnetism (HMFM) has great potential application in spin filter. However, it is extremely rare, especially in two-dimensional (2D) materials. At present, 2D materials have drawn international interest in spintronic devices. Here, we use ab initio density functional theory (DFT) calculations to study the structural stability and electrical and magnetic properties of the MoS2-based 2D superlattice formed by inserting graphene hexagonal ring in 6 × 6 × 1 MoS2 supercell. Two kinds of structures with hexagonal carbon ring were predicted with structural stability and were shown HMFM. The two structures combine the spin transport capacity of graphene with the magnetism of the defective 2D MoS2. And they have strong covalent bonding between the C and S or Mo atoms near the interface. This work is very useful to help us to design reasonable MoS2-based spin filter.

  16. Spectrum Fatigue Lifetime and Residual Strength for Fiberglass Laminates; TOPICAL

    International Nuclear Information System (INIS)

    WAHL, NEIL K.; MANDELL, JOHN F.; SAMBORSKY, DANIEL D.

    2002-01-01

    This report addresses the effects of spectrum loading on lifetime and residual strength of a typical fiberglass laminate configuration used in wind turbine blade construction. Over 1100 tests have been run on laboratory specimens under a variety of load sequences. Repeated block loading at two or more load levels, either tensile-tensile, compressive-compressive, or reversing, as well as more random standard spectra have been studied. Data have been obtained for residual strength at various stages of the lifetime. Several lifetime prediction theories have been applied to the results. The repeated block loading data show lifetimes that are usually shorter than predicted by the most widely used linear damage accumulation theory, Miner's sum. Actual lifetimes are in the range of 10 to 20 percent of predicted lifetime in many cases. Linear and nonlinear residual strength models tend to fit the data better than Miner's sum, with the nonlinear providing a better fit of the two. Direct tests of residual strength at various fractions of the lifetime are consistent with the residual strength models. Load sequencing effects are found to be insignificant. The more a spectrum deviates from constant amplitude, the more sensitive predictions are to the damage law used. The nonlinear model provided improved correlation with test data for a modified standard wind turbine spectrum. When a single, relatively high load cycle was removed, all models provided similar, though somewhat non-conservative correlation with the experimental results. Predictions for the full spectrum, including tensile and compressive loads were slightly non-conservative relative to the experimental data, and accurately captured the trend with varying maximum load. The nonlinear residual strength based prediction with a power law S-N curve extrapolation provided the best fit to the data in most cases. The selection of the constant amplitude fatigue regression model becomes important at the lower stress, higher

  17. c, b, and tau lifetime measurements in e+e- interactions

    International Nuclear Information System (INIS)

    Jaros, J.A.

    1983-01-01

    Experiments at e + e - storage rings have successfully measured the tau and D 0 lifetimes and set interesting limits on the B lifetime. So far, the conventional wisdom has prevailed. The tau lifetime is consistent with prediction; there is no sign (but little sensitivity) of a violation of universality. The charmed particle lifetimes are roughly as expected, but richer in their phenomenology than anticipated. The B lifetime is still unknown. The experimental art is developing rapidly. Several experiments have by now installed vertex detectors. Measurements of charmed particle lifetimes from e + e - experiments will complement the work that has been done at fixed target machines. Measurements of tau and B lifetimes may be the exclusive province of e + e - experiments for the next few years

  18. Lifetime measurements of the strange beauty meson and beauty baryons at LEP

    International Nuclear Information System (INIS)

    Romero, A.

    1994-01-01

    Last experimental results on the lifetimes of B s 0 mesons and beauty baryons from the LEP experiments ALEPH, DELPHI and OPAL are presented. LEP averages for the lifetimes of B s 0 and Λ b are compared to lifetimes of B d 0 and B + and to the average b hadron lifetime. The precision of these measurements begins to be suitable to test the theoretical predictions of 10-15% differences between the lifetimes of b baryons and mesons, but does not allow a test of the few percent difference expected between B d 0 and B + lifetimes. The data show a significant evidence (3 σ) for lifetime differences between b mesons and b baryons. (author). 4 refs., 9 figs

  19. Predicting the Hydraulic Conductivity of Metallic Iron Filters: Modeling Gone Astray

    Directory of Open Access Journals (Sweden)

    Chicgoua Noubactep

    2016-04-01

    Full Text Available Since its introduction about 25 years ago, metallic iron (Fe0 has shown its potential as the key component of reactive filtration systems for contaminant removal in polluted waters. Technical applications of such systems can be enhanced by numerical simulation of a filter design to improve, e.g., the service time or the minimum permeability of a prospected system to warrant the required output water quality. This communication discusses the relevant input quantities into such a simulation model, illustrates the possible simplifications and identifies the lack of relevant thermodynamic and kinetic data. As a result, necessary steps are outlined that may improve the numerical simulation and, consequently, the technical design of Fe0 filters. Following a general overview on the key reactions in a Fe0 system, the importance of iron corrosion kinetics is illustrated. Iron corrosion kinetics, expressed as a rate constant kiron, determines both the removal rate of contaminants and the average permeability loss of the filter system. While the relevance of a reasonable estimate of kiron is thus obvious, information is scarce. As a conclusion, systematic experiments for the determination of kiron values are suggested to improve the database of this key input parameter to Fe0 filters.

  20. Application of Semiempirical Methods to Transition Metal Complexes: Fast Results but Hard-to-Predict Accuracy.

    KAUST Repository

    Minenkov, Yury

    2018-05-22

    A series of semiempirical PM6* and PM7 methods has been tested in reproducing of relative conformational energies of 27 realistic-size complexes of 16 different transition metals (TMs). An analysis of relative energies derived from single-point energy evaluations on density functional theory (DFT) optimized conformers revealed pronounced deviations between semiempirical and DFT methods indicating fundamental difference in potential energy surfaces (PES). To identify the origin of the deviation, we compared fully optimized PM7 and respective DFT conformers. For many complexes, differences in PM7 and DFT conformational energies have been confirmed often manifesting themselves in false coordination of some atoms (H, O) to TMs and chemical transformations/distortion of coordination center geometry in PM7 structures. Despite geometry optimization with fixed coordination center geometry leads to some improvements in conformational energies, the resulting accuracy is still too low to recommend explored semiempirical methods for out-of-the-box conformational search/sampling: careful testing is always needed.

  1. Prediction of Intrinsic Ferromagnetic Ferroelectricity in a Transition-Metal Halide Monolayer

    Science.gov (United States)

    Huang, Chengxi; Du, Yongping; Wu, Haiping; Xiang, Hongjun; Deng, Kaiming; Kan, Erjun

    2018-04-01

    The realization of multiferroics in nanostructures, combined with a large electric dipole and ferromagnetic ordering, could lead to new applications, such as high-density multistate data storage. Although multiferroics have been broadly studied for decades, ferromagnetic ferroelectricity is rarely explored, especially in two-dimensional (2D) systems. Here we report the discovery of 2D ferromagnetic ferroelectricity in layered transition-metal halide systems. On the basis of first-principles calculations, we reveal that a charged CrBr3 monolayer exhibits in-plane multiferroicity, which is ensured by the combination of orbital and charge ordering as realized by the asymmetric Jahn-Teller distortions of octahedral Cr - Br6 units. As an example, we further show that (CrBr3)2Li is a ferromagnetic ferroelectric multiferroic. The explored phenomena and mechanism of multiferroics in this 2D system not only are useful for fundamental research in multiferroics but also enable a wide range of applications in nanodevices.

  2. Predicting arsenic and heavy metals contamination in groundwater resources of Ghahavand plain based on an artificial neural network optimized by imperialist competitive algorithm

    Directory of Open Access Journals (Sweden)

    Meysam Alizamir

    2017-10-01

    Full Text Available Background: The effects of trace elements on human health and the environment gives importance to the analysis of heavy metals contamination in environmental samples and, more particularly, human food sources. Therefore, the current study aimed to predict arsenic and heavy metals (Cu, Pb, and Zn contamination in the groundwater resources of Ghahavand Plain based on an artificial neural network (ANN optimized by imperialist competitive algorithm (ICA. Methods: This study presents a new method for predicting heavy metal concentrations in the groundwater resources of Ghahavand plain based on ANN and ICA. The developed approaches were trained using 75% of the data to obtain the optimum coefficients and then tested using 25% of the data. Two statistical indicators, the coefficient of determination (R2 and the root-mean-square error (RMSE, were employed to evaluate model performance. A comparison of the performances of the ICA-ANN and ANN models revealed the superiority of the new model. Results of this study demonstrate that heavy metal concentrations can be reliably predicted by applying the new approach. Results: Results from different statistical indicators during the training and validation periods indicate that the best performance can be obtained with the ANN-ICA model. Conclusion: This method can be employed effectively to predict heavy metal concentrations in the groundwater resources of Ghahavand plain.

  3. Uncertainty analysis of the nonideal competitive adsorption-donnan model: effects of dissolved organic matter variability on predicted metal speciation in soil solution.

    Science.gov (United States)

    Groenenberg, Jan E; Koopmans, Gerwin F; Comans, Rob N J

    2010-02-15

    Ion binding models such as the nonideal competitive adsorption-Donnan model (NICA-Donnan) and model VI successfully describe laboratory data of proton and metal binding to purified humic substances (HS). In this study model performance was tested in more complex natural systems. The speciation predicted with the NICA-Donnan model and the associated uncertainty were compared with independent measurements in soil solution extracts, including the free metal ion activity and fulvic (FA) and humic acid (HA) fractions of dissolved organic matter (DOM). Potentially important sources of uncertainty are the DOM composition and the variation in binding properties of HS. HS fractions of DOM in soil solution extracts varied between 14 and 63% and consisted mainly of FA. Moreover, binding parameters optimized for individual FA samples show substantial variation. Monte Carlo simulations show that uncertainties in predicted metal speciation, for metals with a high affinity for FA (Cu, Pb), are largely due to the natural variation in binding properties (i.e., the affinity) of FA. Predictions for metals with a lower affinity (Cd) are more prone to uncertainties in the fraction FA in DOM and the maximum site density (i.e., the capacity) of the FA. Based on these findings, suggestions are provided to reduce uncertainties in model predictions.

  4. Spectroscopy and lifetime of bottom and charm hadrons

    International Nuclear Information System (INIS)

    F. Ukegawa

    2000-01-01

    There are several motivations for studying masses and lifetimes of the hadrons containing a heavy quark, either the bottom or the charm quark. First, the mass and the lifetime are fundamental properties of an elementary particle. Second, the spectroscopy of hadrons gives insights into the QCD potential between quarks. In particular, a symmetry exists for heavy hadrons when the heavy quark mass is taken to be infinite, providing a powerful tool to predict and understand properties of those heavy hadrons. Third, studies of the lifetimes of heavy hadrons probe their decay mechanisms. A measurement of the lifetime, or the total decay width, is necessary when the authors extract magnitudes of elements of the Kobayashi-Maskawa matrix. Again, in the limit of an infinite heavy quark mass things become simple and decay of a heavy hadron should be the decay of the heavy quark Q. This leads to a prediction that all hadrons containing the heavy quark Q should have the same lifetime, that of the quark Q. This is far from reality in the case of charm hadrons, where the D + meson lifetime is about 2.5 times longer than the D 0 meson lifetime. Perhaps the charm quark is not heavy enough. The simple quark decay picture should be a better approximation for the bottom hadrons because of the larger b quark mass. On the experimental side, the measurements and knowledge of the heavy hadrons (in particular bottom hadrons) have significantly improved over the last decade, thanks to high statistics data accumulated by various experiments. The authors shall review recent developments in these studies in the remainder of this manuscript

  5. Effect of material environment on a class of nuclear lifetimes

    International Nuclear Information System (INIS)

    Perlow, G.J.

    1988-01-01

    The connection between internal conversion of a nuclear transition and EXAFS is pointed out. A prediction is made of sizable variations of lifetimes of nuclear states depending on the surrounding material environment, provided that the transition energy is just above threshold and the internal conversion coefficient is appreciable. 12 refs., 2 figs

  6. Predictive calculations of volatilities of metals and oxides in steam-containing environments

    International Nuclear Information System (INIS)

    Krikorian, O.H.

    1981-01-01

    Predictive methods are developed for estimating the bond energies and free energy functions of volatile species having the general formula MO/sub x/ (OH)/sub y/, in order to shed some light on the mechanisms and extent of steam accelerated volatilization processes. A specific example of applying the data is illustrated for the case of a proposed underground radioactive waste disposal process, where oxides of radionuclides are allowed to equilibrate with 100 atm steam and 10 -2 atm oxygen at 1000 to 2000K. Vapor species found to have high volatilities include Cs 2 (OH) 2 , CsOH, AmO 2 (OH) 2 , AmO(OH) 3 , UO 2 (OH) 2 , NbO(OH) 3 , PuO 2 (OH) 2 , CeO(OH) 2 , Ba(OH) 2 , and Eu(OH) 3 . Thermodynamic data are tabulated for all possible monomeric species for this specific example

  7. Lifetime of a black hole

    International Nuclear Information System (INIS)

    Carlitz, R.D.; Willey, R.S.

    1987-01-01

    We study the constraints placed by quantum mechanics upon the lifetime of a black hole. In the context of a moving-mirror analog model for the Hawking radiation process, we conclude that the period of Hawking radiation must be followed by a much longer period during which the remnant mass (of order m/sub P/) may be radiated away. We are able to place a lower bound on the time required for this radiation process, which translates into a lower bound for the lifetime of the black hole. Particles which are emitted during the decay of the remnant, like the particles which comprise the Hawking flux, may be uncorrelated with each other. But each particle emitted from the decaying remnant is correlated with one particle emitted as Hawking radiation. The state which results after the remnant has evaporated is one which locally appears to be thermal, but which on a much larger scale is marked by extensive correlations

  8. Luminosity lifetime in the Tevatron

    International Nuclear Information System (INIS)

    Jackson, G.; Finley, D.; Johnson, R.P.; Kerns, Q.; McCarthy, J.; Siemann, R.; Zhang, P.

    1988-01-01

    Since the inauguration of colliding proton-antiproton operations in 1987, the Tevatron has exhibited luminosity lifetimes shorter than expected. During a typical colliding beam storage period, called a store, luminosity is calculated periodically by measuring the charge and emittances of each bunch. The growth of the transverse bunch emittances is the dominant cause of luminosity deterioration. Throughout, this period, the position spectrum of the bunches exhibited betatron signals larger than expected from Schottky noise. A model assuming externally driven betatron oscillations explains both the betatron signals and the emittance growth. A program is underway to improve the Tevatron luminosity lifetime. The abort kickers have been identified as sources of emittance growth, and some quadrupole power supplies are further candidates. Because the horizontal dispersion through the RF cavities is nonzero, RF phase noise has been investigated. Noise in the main dipole regulation circuit has also been studied. 13 refs., 4 figs

  9. Angular distributions as lifetime probes

    Energy Technology Data Exchange (ETDEWEB)

    Dror, Jeff Asaf; Grossman, Yuval [Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States)

    2014-06-27

    If new TeV scale particles are discovered, it will be important to determine their width. There is, however, a problematic region, where the width is too small to be determined directly, and too large to generate a secondary vertex. For a collection of colored, spin polarized particles, hadronization depolarizes the particles prior to their decay. The amount of depolarization can be used to probe the lifetime in the problematic region. In this paper we apply this method to a realistic scenario of a top-like particle that can be produced at the LHC. We study how depolarization affects the angular distributions of the decay products and derive an equation for the distributions that is sensitive to the lifetime.

  10. Lifetime evaluation for thermal fatigue: application at the first wall of a tokamak fusion reactor

    International Nuclear Information System (INIS)

    Merola, M.; Biggio, M.

    1989-01-01

    Thermal fatigue seems to be the most lifetime limiting phenomenon for the first wall of the next generation Tokamak fusion reactors. This work deals with the problem of the thermal fatigue in relation to the lifetime prediction of the fusion reactor first wall. The aim is to compare different lifetime methodologies among them and with experimental results. To fulfil this purpose, it has been necessary to develop a new numerical methodology, called reduced-3D, especially suitable for thermal fatigue problems

  11. Lifetime embrittlement of reactor core materials

    International Nuclear Information System (INIS)

    Kreyns, P.H..; Bourgeois, W.F.; Charpentier, P.L.; Kammenzind, B.F.; Franklin, D.G.; White, C.J.

    1994-08-01

    Over a core lifetime, the reactor materials Zircaloy-2, Zircaloy-4, and hafnium may become embrittled due to the absorption of corrosion- generated hydrogen and to neutron irradiation damage. Results are presented on the effects of fast fluence on the fracture toughness of wrought Zircaloy-2, Zircaloy-4, and hafnium; Zircaloy-4 to hafnium butt welds; and hydrogen precharged beta treated and weld metal Zircaloy-4 for fluences up to a maximum of approximately 150 x 10 24 n/M 2 (> 1 Mev). While Zircaloy-4 did not exhibit a decrement in K IC due to irradiation, hafnium and butt welds between hafnium and Zircaloy-4 are susceptible to embrittlement with irradiation. The embrittlement can be attributed to irradiation strengthening, which promotes cleavage fracture in hafnium and hafnium-Zircaloy welds, and, in part, to the lower chemical potential of hydrogen in Zircaloy-4 compared to hafnium, which causes hydrogen, over time, to drift from the hafnium end toward the Zircaloy-4 end and to precipitate at the interface between the weld and base-metal interface. Neutron radiation apparently affects the fracture toughness of Zircaloy-2, Zircaloy-4, and hafnium in different ways. Possible explanations for these differences are suggested. It was found that Zircaloy-4 is preferred over Zircaloy-2 in hafnium-to- Zircaloy butt-weld applications due to its absence of a radiation- induced reduction in K IC plus its lower hydrogen absorption characteristics compared with Zircaloy-2

  12. Theory and models of material erosion and lifetime during plasma instabilities in a tokamak environment

    International Nuclear Information System (INIS)

    Hassanein, A.; Konkashbaev, I.

    1999-01-01

    Surface and structural damage to plasma-facing components (PFCs) due to the frequent loss of plasma confinement remains a serious problem for the tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure, and frequent plasma contamination. Surface damage consists of vaporization, spallation, and liquid splatter of metallic materials. Structural damage includes large temperature increases in structural materials and at the interfaces between surface coatings and structural members. To evaluate the lifetimes of plasma-facing materials and nearby components and to predict the various forms of damage that they experience, comprehensive models (contained in the HEIGHTS computer simulation package) are developed, integrated self-consistently, and enhanced. Splashing mechanisms such as bubble boiling and various liquid magnetohydrodynamic instabilities and brittle destruction mechanisms of nonmelting materials are being examined. The design requirements and implications of plasma-facing and nearby components are discussed, along with recommendations to mitigate and reduce the effects of plasma instabilities on reactor components

  13. International Thermonuclear Experimental Reactor (ITER) divertor plate performance and lifetime considerations

    International Nuclear Information System (INIS)

    Mattas, R.F.

    1990-03-01

    The ITER divertor plate performance during the technology phase of operation has been analyzed. High-Z materials, such as tungsten and tantalum, have been considered as plasma side materials, and refractory metal alloys, Ta-10W, TZM, Nb-1Zr, and V-15Cr-5Ti, plus copper alloys have been considered as the structural materials. The fatigue lifetime have been predicted for structural plates and for duplex plates with the plasma side material bonded to the structure. The results indicate that refractory alloys have a comparable or improved performance to copper alloys. Peak allowable heat fluxes for these analyses are in the range of 15--20 MW/m 2 for 2 mm thick structural plates and 7--11 MW/m 2 for 4 mm thick duplex plates. 4 refs., 55 figs., 6 tabs

  14. Parity lifetime of bound states in a proximitized semiconductor nanowire

    DEFF Research Database (Denmark)

    Higginbotham, Andrew Patrick; Albrecht, Sven Marian; Kirsanskas, Gediminas

    2015-01-01

    Quasiparticle excitations can compromise the performance of superconducting devices, causing high frequency dissipation, decoherence in Josephson qubits, and braiding errors in proposed Majorana-based topological quantum computers. Quasiparticle dynamics have been studied in detail in metallic...... superconductor layer, yielding an isolated, proximitized nanowire segment. We identify Andreev-like bound states in the semiconductor via bias spectroscopy, determine the characteristic temperatures and magnetic fields for quasiparticle excitations, and extract a parity lifetime (poisoning time) of the bound...

  15. Stage of hilar cholangiocarcinoma predicts recurrence of biliary obstruction in patients with metal stents.

    Science.gov (United States)

    Siddiqui, Ali; Shahid, Haroon; Sarkar, Avik; Cox, Kristen; Kowalski, Thomas E; Loren, David E; Sharma, Ashish; Laing, Patrick; Birch, Madeline; Adler, Douglas G

    2013-09-01

    Most patients with hilar cholangiocarcinomas present with unresectable tumors, so only palliative biliary drainage with self-expanding metal stents (SEMS) is possible. Stents eventually cease to function because of tumor overgrowth and/or other causes, so it is important to identify factors that affect stent patency and failure. We examined the patency of endoscopically placed SEMS in patients with hilar cholangiocarcinoma and factors associated with patency. We performed a retrospective study of 120 consecutive patients (mean age, 67 ± 14.6 years; 74 male) who presented with obstructive jaundice from hilar cholangiocarcinoma and underwent bilateral SEMS from September 2006 through April 2012 at 2 US tertiary medical centers. We collected data on patient demographics and survival, success of stent placement and function, and immediate adverse events. The primary outcome was duration of stent patency (time from insertion to failure). Thirty-eight patients had stage 1 hilar cholangiocarcinomas, 45 had stage 2, 12 had stage 3, and 25 had stage 4. The median length of the hilar stricture was 9 mm (range, 8-50 mm). The stent was successfully passaged across the stricture in all patients and was functional in 115; its median length was 8 mm (range, 8-10 mm), and diameter was 80 mm (range, 60-100 mm). Fourteen patients had immediate adverse events, including perforation (n = 2), bleeding (n = 2), pancreatitis (n = 9), and cholangitis (n = 1). Median survival was 17 weeks (range, 1-211 weeks), and 50 patients had stent occlusion. On Kaplan-Meier analysis, the median time from stent placement to occlusion was 17 weeks (range, 1-104 weeks). More patients with stage 3 or 4 tumors (64%) had SEMS occlusion than patients with stage 1 or 2 tumors (28%) in univariate analysis (P = .017). In multivariate analysis, only cancer stage was independently and significantly associated with patency (P = .006; hazard ratio, 2.77); age, sex, length of stricture, and SEMS diameter and

  16. Modeling and Application of Customer Lifetime Value in Online Retail

    OpenAIRE

    Pavel Jasek; Lenka Vrana; Lucie Sperkova; Zdenek Smutny; Marek Kobulsky

    2018-01-01

    This article provides an empirical statistical analysis and discussion of the predictive abilities of selected customer lifetime value (CLV) models that could be used in online shopping within e-commerce business settings. The comparison of CLV predictive abilities, using selected evaluation metrics, is made on selected CLV models: Extended Pareto/NBD model (EP/NBD), Markov chain model and Status Quo model. The article uses six online store datasets with annual revenues in the order of tens o...

  17. Minority Carrier Lifetime Studies of Narrow Bandgap Antimonide Superlattices

    Science.gov (United States)

    Hoglund, Linda; Ting, David Z.; Khoshakhlagh, Arezou; Soibel, Alexander; Hill, Cory J.; Fisher, Anita; Keo, Sam; Gunapala, Sarath D.

    2014-01-01

    In this study optical modulation response and photoluminescence spectroscopy were used to study mid-wave Ga-free InAs/InAsSb superlattices. The minority carrier lifetimes in the different samples varied from 480 ns to 4700 ns, partly due to different background doping concentrations. It was shown that the photoluminescence intensity can be used as a fast non-destructive tool to predict the material quality. It was also demonstrated that it is crucial to use a low excitation power in the photoluminescence measurements in order to get a good correlation between the photoluminescence intensity and the minority carrier lifetime.

  18. A model for prediction of fume formation rate in gas metal arc welding (GMAW), globular and spray modes, DC electrode positive.

    Science.gov (United States)

    Dennis, J H; Hewitt, P J; Redding, C A; Workman, A D

    2001-03-01

    Prediction of fume formation rate during metal arc welding and the composition of the fume are of interest to occupational hygienists concerned with risk assessment and to manufacturers of welding consumables. A model for GMAW (DC electrode positive) is described based on the welder determined process parameters (current, wire feed rate and wire composition), on the surface area of molten metal in the arc and on the partial vapour pressures of the component metals of the alloy wire. The model is applicable to globular and spray welding transfer modes but not to dip mode. Metal evaporation from a droplet is evaluated for short time increments and total evaporation obtained by summation over the life of the droplet. The contribution of fume derived from the weld pool and spatter (particles of metal ejected from the arc) is discussed, as are limitations of the model. Calculated droplet temperatures are similar to values determined by other workers. A degree of relationship between predicted and measured fume formation rates is demonstrated but the model does not at this stage provide a reliable predictive tool.

  19. Maintenance engineering of lifetime management programs

    International Nuclear Information System (INIS)

    Hervia Ruperez, F.

    1997-01-01

    The complexity of nuclear power plants obliges to stablish the adecuated management of its lifetime. This article describes the methodologies and the improvement the evaluation of lifetime programs and specially in Garona and Vandellos II Nuclear Power Plants. (Author)

  20. Review of charm and beauty lifetimes

    International Nuclear Information System (INIS)

    Cheung, Harry W. K.

    1999-01-01

    A review of the latest experimental results on charm and beauty particle lifetimes is presented together with a brief summary of measurement methods used for beauty particle lifetime measurements. There have been significant updates to the D s + /D 0 , B + /B d 0 and Λ b 0 /B d 0 lifetime ratios which have some theoretical implications. However more precise measurements are still needed before one can make conclusive statements about the theory used to calculate the particle lifetimes

  1. Predicting criteria continuous concentrations of 34 metals or metalloids by use of quantitative ion character-activity relationships-species sensitivity distributions (QICAR-SSD) model.

    Science.gov (United States)

    Mu, Yunsong; Wu, Fengchang; Chen, Cheng; Liu, Yuedan; Zhao, Xiaoli; Haiqing Liao; Giesy, John P

    2014-05-01

    Criteria continuous concentrations (CCCs) are useful for describing chronic exposure to pollutants and setting water quality standards to protect aquatic life. However, because of financial, practical, or ethical restrictions on toxicity testing, few data are available to derive CCCs. In this study, CCCs for 34 metals or metalloids were derived using quantitative ion character-activity relationships-species sensitivity distributions (QICAR-SSD) and the final acute-chronic ratio (FACR) method. The results showed that chronic toxic potencies were correlated with several physico-chemical properties among eight species chosen, where the softness index was the most predictive characteristic. Predicted CCCs for most of the metals, except for Lead and Iron, were within a range of 10-fold of values recommended by the U.S. EPA. The QICAR-SSD model was superior to the FACR method for prediction of data-poor metals. This would have significance for predicting toxic potencies and criteria thresholds of more metals or metalloids. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Lifetime physical activity and female stress urinary incontinence.

    Science.gov (United States)

    Nygaard, Ingrid E; Shaw, Janet M; Bardsley, Tyler; Egger, Marlene J

    2015-07-01

    We sought to estimate whether moderate/severe stress urinary incontinence (SUI) in middle-aged women is associated with overall lifetime physical activity (including leisure, household, outdoor, and occupational), as well as lifetime leisure (recreational), lifetime strenuous, and strenuous activity during the teen years. Recruitment for this case-control study was conducted in primary-care-level family medicine and gynecology clinics. A total of 1538 enrolled women ages 39-65 years underwent a Pelvic Organ Prolapse Quantification examination to assess vaginal support. Based on Incontinence Severity Index scores, cases had moderate/severe and controls had no/mild SUI. We excluded 349 with vaginal descent at/below the hymen (pelvic organ prolapse), 194 who did not return questionnaires, and 110 with insufficient activity data for analysis. In all, 213 cases were frequency matched 1:1 by age group to controls. Physical activity was measured using the Lifetime Physical Activity Questionnaire, in which women recall activity from menarche to present. We created separate multivariable logistic regression models for activity measures. SUI odds increased slightly with overall lifetime activity (odds ratio [OR], 1.20 per 70 additional metabolic equivalent of task-h/wk; 95% confidence interval [CI], 1.02-1.41), and were not associated with lifetime strenuous activity (OR, 1.11; 95% CI, 0.99-1.25). In quintile analysis of lifetime leisure activity, which demonstrated a nonlinear pattern, all quintiles incurred about half the odds of SUI compared to reference (second quintile; P = .009). Greater strenuous activity in teen years modestly increased SUI odds (OR, 1.37 per 7 additional h/wk; 95% CI, 1.09-1.71); OR, 1.75; 95% CI, 1.15-2.66 in sensitivity analysis adjusting for measurement error. The predicted probability of SUI rose linearly in women exceeding 7.5 hours of strenuous activity/wk during teen years. Teen strenuous activity had a similar effect on SUI odds when

  3. Lifetime of chaotic attractors in a multidimensional laser system

    International Nuclear Information System (INIS)

    Pando L, C.L.; Cerdeira, H.A.

    1995-01-01

    We study the lifetimes of chaotic attractors at crises in a multidimensional laser system. This system describes the CO 2 laser with modulated losses and is known as the four-level model. The critical exponents which are related to the lifetimes of the attractors are estimated in terms of the corresponding eigenvalues and the measured characteristic lifetime in the model. The critical exponents in this model and those of its center manifold version are in good agreement. We conjecture that generically in the four-level model the critical exponents are close to 1/2 at crises. In addition, we compare predictions of a simpler and popular model known as the two-level model with those of the above mentioned models. (author). 21 refs, 2 figs, 3 tabs

  4. On luminescence lifetimes in quartz

    International Nuclear Information System (INIS)

    Chithambo, M.L.; Galloway, R.B.

    2000-01-01

    In this paper we present results of investigations concerning the time dependence of luminescence emission relative to the time of stimulation in quartz. Measurements of time-resolved spectra were performed on a new versatile pulsed light emitting diode system using 525 nm stimulation, an 11 μs duration pulse, a repetition rate of 11 kHz and a 64 μs dynamic range. Effects on luminescence lifetime resulting from sample treatments such as optical stimulation, irradiation, and preheating, are reported

  5. Lifetime measurement in 144Gd

    International Nuclear Information System (INIS)

    Jensen, H.J.; Gast, W.; Georgiev, A.; Jaeger, H.M.; Lieder, R.M.; Utzelmann, S.; Gierlik, M.; Morek, T.; Przestrzelska, K.; Rzaca-Urban, T.; Dewald, A.; Kuehn, R.; Meier, C.; Ender, C.; Haertlein, T.

    1996-01-01

    The lifetime measurements of excited states in 144 Gd were carried out using the Koeln RDM-plunger together with the 2 x 3 CLUSTER detector setup in Heidelberg. The nucleus was populated in the 100 Mo( 48 Ti,4n) 144 Gd reaction at a beam energy of 205 MeV giving a recoil velocity of v/c = 2.6 %. Three and higher fold γ-ray coincidences were measured at 12 target-stopper distances ranged from 0 to 400 μm. Both the dipole and quadrupole bands in 144 Gd have been observed. The analysis is in progress

  6. Lifetime of superheated steam components

    International Nuclear Information System (INIS)

    Stoklossa, K.H.; Oude-Hengel, H.H.; Kraechter, H.J.

    1974-01-01

    The current evaluation schemes in use for judging the lifetime expectations of superheated steam components are compared with each other. The influence of pressure and temperature fluctuations, the differences in the strength of the wall, and the spread band of constant-strainrates are critically investigated. The distribution of these contributory effects are demonstrated in the hight of numerous measuring results. As an important supplement to these evaluation schemes a newly developed technique is introduced which is designed to calculate failure probabilities. (orig./RW) [de

  7. The mass-lifetime relation

    Science.gov (United States)

    LoPresto, Michael C.

    2018-05-01

    In a recent "AstroNote," I described a simple exercise on the mass-luminosity relation for main sequence stars as an example of exposing students in a general education science course of lower mathematical level to the use of quantitative skills such as collecting and analyzing data. Here I present another attempt at a meaningful experience for such students that again involves both the gathering and analysis of numerical data and comparison with accepted result, this time on the relationship of the mass and lifetimes of main sequence stars. This experiment can stand alone or be used as an extension of the previous mass-luminosity relationship experiment.

  8. The puzzle of neutron lifetime

    International Nuclear Information System (INIS)

    Paul, Stephan

    2009-01-01

    In this paper we review the role of the neutron lifetime and discuss the present status of measurements. In view of the large discrepancy observed by the two most precise individual measurements so far we describe the different techniques and point out the principle strengths and weaknesses. In particular we discuss the estimation of systematic uncertainties and its correlation to the statistical ones. In order to solve the present puzzle, many new experiments are either ongoing or being proposed. An overview on their possible contribution to this field will be given.

  9. Personality, IQ, and Lifetime Earnings

    DEFF Research Database (Denmark)

    Gensowski, Miriam

    2018-01-01

    This paper estimates the effects of personality traits and IQ on lifetime earnings of the men and women of the Terman study, a high-IQ U.S. sample. Age-by-age earnings profiles allow a study of when personality traits affect earnings most, and for whom the effects are strongest. I document...... a concave life-cycle pattern in the payoffs to personality traits, with the largest effects between the ages of 40 and 60. An interaction of traits with education reveals that personality matters most for highly educated men. The largest effects are found for Conscientiousness, Extraversion...

  10. Lifetime measurement in 136Pm

    International Nuclear Information System (INIS)

    Toney, D.; Zhong, Q.; De Angelis, G.

    2005-01-01

    The aim of the present work is to investigate the electromagnetic transition probabilities in the doublet bands of 136 Pm. These two bands have been observed up to Iπ = (21 + ). Contrary to the case of 134 Pr, the B(M1)/B(E2) ratios take similar values within the error bars in 136 Pm. This is a strong indication that there is considerable difference between the two nuclei. However, a lifetime measurement in 136 Pm is needed to shed light on the scale and the origin of the difference

  11. Ab-Initio Description and Prediction of Properties of Carbon-Based and Other Non-Metallic Materials

    Science.gov (United States)

    Bagayoko, D.; Zhao, G. L.; Hasan, S.

    2001-01-01

    We have resolved the long-standing problem consisting of 30%-50% theoretical underestimates of the band gaps of non-metallic materials. We describe the Bagayoko, Zhao, and Williams (BZW) method that rigorously circumvents the basis-set and variational effect presumed to be a cause of these underestimates. We present ab-initio, computational results that are in agreement with experiment for diamond (C), silicon (Si), silicon carbides (3C-SiC and 4H-SiC), and other semiconductors (GaN, BaTiO3, AlN, ZnSe, ZnO). We illustrate the predictive capability of the BZW method in the case of the newly discovered cubic phase of silicon nitride (c-Si3N4) and of selected carbon nanotabes [(10,0), and (8,4)]. Our conclusion underscores the inescapable need for the BZW method in ab-initio calculations that employ a basis set in a variational approach. Current nanoscale trends amplify this need. We estimate that the potential impact of applications of the BZW method in advancing our understanding of nonmetallic materials, in informing experiment, and particularly in guiding device design and fabrication is simply priceless.

  12. Uncertainties in the proton lifetime

    International Nuclear Information System (INIS)

    Ellis, J.; Nanopoulos, D.V.; Rudaz, S.; Gaillard, M.K.

    1980-04-01

    We discuss the masses of the leptoquark bosons m(x) and the proton lifetime in Grand Unified Theories based principally on SU(5). It is emphasized that estimates of m(x) based on the QCD coupling and the fine structure constant are probably more reliable than those using the experimental value of sin 2 theta(w). Uncertainties in the QCD Λ parameter and the correct value of α are discussed. We estimate higher order effects on the evolution of coupling constants in a momentum space renormalization scheme. It is shown that increasing the number of generations of fermions beyond the minimal three increases m(X) by almost a factor of 2 per generation. Additional uncertainties exist for each generation of technifermions that may exist. We discuss and discount the possibility that proton decay could be 'Cabibbo-rotated' away, and a speculation that Lorentz invariance may be violated in proton decay at a detectable level. We estimate that in the absence of any substantial new physics beyond that in the minimal SU(5) model the proton lifetimes is 8 x 10 30+-2 years

  13. Risk Assessment and Prediction of Heavy Metal Pollution in Groundwater and River Sediment: A Case Study of a Typical Agricultural Irrigation Area in Northeast China

    Directory of Open Access Journals (Sweden)

    Shuang Zhong

    2015-01-01

    Full Text Available The areas with typical municipal sewage discharge river and irrigation water function were selected as study sites in northeast China. The samples from groundwater and river sediment in this area were collected for the concentrations and forms of heavy metals (Cr(VI, Cd, As, and Pb analysis. The risk assessment of heavy metal pollution was conducted based on single-factor pollution index (I and Nemerow pollution index (NI. The results showed that only one groundwater sampling site reached a polluted level of heavy metals. There was a high potential ecological risk of Cd on the N21-2 sampling site in river sediment. The morphological analysis results of heavy metals in sediment showed that the release of heavy metals can be inferred as one of the main pollution sources of groundwater. In addition, the changes in the concentration and migration scope of As were predicted by using the Groundwater Modeling System (GMS. The predicted results showed that As will migrate downstream in the next decade, and the changing trend of As polluted areas was changed with As content districts because of some pump wells downstream to form groundwater depression cone, which made the solute transfer upstream.

  14. Risk Assessment and Prediction of Heavy Metal Pollution in Groundwater and River Sediment: A Case Study of a Typical Agricultural Irrigation Area in Northeast China

    Science.gov (United States)

    Zhong, Shuang; Geng, Hui; Zhang, Fengjun; Liu, Zhaoying; Wang, Tianye; Song, Boyu

    2015-01-01

    The areas with typical municipal sewage discharge river and irrigation water function were selected as study sites in northeast China. The samples from groundwater and river sediment in this area were collected for the concentrations and forms of heavy metals (Cr(VI), Cd, As, and Pb) analysis. The risk assessment of heavy metal pollution was conducted based on single-factor pollution index (I) and Nemerow pollution index (NI). The results showed that only one groundwater sampling site reached a polluted level of heavy metals. There was a high potential ecological risk of Cd on the N21-2 sampling site in river sediment. The morphological analysis results of heavy metals in sediment showed that the release of heavy metals can be inferred as one of the main pollution sources of groundwater. In addition, the changes in the concentration and migration scope of As were predicted by using the Groundwater Modeling System (GMS). The predicted results showed that As will migrate downstream in the next decade, and the changing trend of As polluted areas was changed with As content districts because of some pump wells downstream to form groundwater depression cone, which made the solute transfer upstream. PMID:26366176

  15. Oxidation-induced phase transformations and lifetime limits of chromia-forming nickel-base alloy 625

    Energy Technology Data Exchange (ETDEWEB)

    Chyrkin, Anton

    2011-12-05

    in literature as uphill-diffusion phenomenon. Also the M{sub 6}C carbide is found to dissolve in the subsurface zone during high-temperature oxidation of alloy 625 although chromium is only a minor constituent in this (Ni{sub 3}Mo{sub 3})C base carbide The thermodynamic calculations revealed the carbide dissolution to find its cause in the increasing carbon activity with decreasing chromium content which forced carbon to diffuse back from the subscale zone towards the bulk alloy resulting in carbide dissolution beneath the chromia scale. SPE is experimentally found to be substantially less pronounced in thin foils than in thick specimens of alloy 625. It could be shown that this effect is related to the smaller reservoirs of the scale-forming element chromium as well as that of the δ-Ni{sub 3}Nb phase stabilizing element niobium in the thin specimens. As the thinner specimens (thickness in the range of 0.1 mm) become more rapidly depleted in chromium resulting in flatter chromium depletion profiles, a smaller driving force for uphill-diffusion of Nb towards the scale/alloy interface leads to a substantially less pronounced δ-phase enrichment/depletion than in specimens of a few mm thickness. Decreasing specimen thickness suppresses the enrichment/depletion process of the δ-Ni{sub 3}Nb phase and results in complete dissolution of the M{sub 6}C carbide after longer exposure times. SPE is not observed during oxidation of extremely thin-walled specimens, e.g. extremely thin foils or metal foam particles fabricated from alloy 625. During high-temperature oxidation of metal foams consisting of e.g. 20-60 µm diameter particles, the δ-Ni{sub 3}Nb phase enrichment at the scale/alloy interface does not occur and can thus be virtually ignored when modelling the oxidation-induced lifetime limits of alloy 625 metal foams. The lifetime prediction based on the finite-difference calculation of the chromium depletion at the metal/oxide interface of a spherical metal foam

  16. Personality, IQ, and Lifetime Earnings

    DEFF Research Database (Denmark)

    Gensowski, Miriam

    2014-01-01

    Talented individuals are seen as drivers of long-term growth, but how do they realize their full potential? In this paper, I show that lifetime earnings of high-IQ men and women are substantially influenced by their personality traits, in addition to intelligence and education. Personality traits......, as identified in a factor model, significantly affect earnings, but not for young workers. The effects are furthermore heterogeneous by educational attainment. For women, personality traits do not affect family earnings in the same way as own earnings. Personality and IQ also influence earnings indirectly...... through education, which has sizeable positive rates of return for men in this sample. Women’s returns to education past a bachelor’s degree are lowered through worse marriage prospects, which offset gains to education in terms of own earnings. The causal effect of education is identified through matching...

  17. Measurement of the BS lifetime

    International Nuclear Information System (INIS)

    Siccama, I.

    1996-01-01

    This thesis presents a measurement of the B s lifetime using 3 million hadronic Z decays collected by the DELPHI detector at LEP from 1991 to 1994. Decays of B s mesons are tagged by the reconstruction of a D s - →φπ - or D s - →K *0 K - decay (including the charge conjugated states of these decay modes). The decay time is obtained by reconstructing both the B s momentum and the B s flight distance. The combined result for the D s -lepton and D s -hadron samples is: τ(B s )=1.54±0.31±0.15 ps where the first error is statistical and the second is systematic. (orig./HSI)

  18. Quasi-particle lifetime broadening in normal-superconductor junctions with UPt3

    International Nuclear Information System (INIS)

    Wilde, T. de; Argonne National Lab., IL; Klapwijk, T.M.; Rijksuniversiteit Groningen; Rijksuniversiteit Groningen; Jansen, A.G.M.; Heil, J.; Wyder, P.

    1996-01-01

    For the Andreev-reflection process of quasi-particles at a normal-metal-superconductor interface the influence of lifetime broadening of the quasi-particles on the current-voltage characteristics of NS point contacts is analyzed along the lines of the Blonder-Tinkham-Klapwijk model. The anomalous Andreev-reflection spectra obtained for the heavy-fermion compound UPt 3 cannot be explained by lifetime broadening alone. Instead, an anisotropic superconducting order parameter has to be assumed which, if also lifetime broadening is included, leads to a fairly good agreement with the data. (orig.)

  19. From basic physics to mechanisms of toxicity: the ``liquid drop'' approach applied to develop predictive classification models for toxicity of metal oxide nanoparticles

    Science.gov (United States)

    Sizochenko, Natalia; Rasulev, Bakhtiyor; Gajewicz, Agnieszka; Kuz'min, Victor; Puzyn, Tomasz; Leszczynski, Jerzy

    2014-10-01

    Many metal oxide nanoparticles are able to cause persistent stress to live organisms, including humans, when discharged to the environment. To understand the mechanism of metal oxide nanoparticles' toxicity and reduce the number of experiments, the development of predictive toxicity models is important. In this study, performed on a series of nanoparticles, the comparative quantitative-structure activity relationship (nano-QSAR) analyses of their toxicity towards E. coli and HaCaT cells were established. A new approach for representation of nanoparticles' structure is presented. For description of the supramolecular structure of nanoparticles the ``liquid drop'' model was applied. It is expected that a novel, proposed approach could be of general use for predictions related to nanomaterials. In addition, in our study fragmental simplex descriptors and several ligand-metal binding characteristics were calculated. The developed nano-QSAR models were validated and reliably predict the toxicity of all studied metal oxide nanoparticles. Based on the comparative analysis of contributed properties in both models the LDM-based descriptors were revealed to have an almost similar level of contribution to toxicity in both cases, while other parameters (van der Waals interactions, electronegativity and metal-ligand binding characteristics) have unequal contribution levels. In addition, the models developed here suggest different mechanisms of nanotoxicity for these two types of cells.Many metal oxide nanoparticles are able to cause persistent stress to live organisms, including humans, when discharged to the environment. To understand the mechanism of metal oxide nanoparticles' toxicity and reduce the number of experiments, the development of predictive toxicity models is important. In this study, performed on a series of nanoparticles, the comparative quantitative-structure activity relationship (nano-QSAR) analyses of their toxicity towards E. coli and HaCaT cells were

  20. Effective carrier sweepout in a silicon waveguide by a metal-semiconductor-metal structure

    DEFF Research Database (Denmark)

    Ding, Yunhong; Hu, Hao; Ou, Haiyan

    2015-01-01

    We demonstrate effective carrier depletion by metal-semiconductor-metal junctions for a silicon waveguide. Photo-generated carriers are efficiently swept out by applying bias voltages, and a shortest carrier lifetime of only 55 ps is demonstrated.......We demonstrate effective carrier depletion by metal-semiconductor-metal junctions for a silicon waveguide. Photo-generated carriers are efficiently swept out by applying bias voltages, and a shortest carrier lifetime of only 55 ps is demonstrated....

  1. Time series models for prediction the total and dissolved heavy metals concentration in road runoff and soil solution of roadside embankments

    Science.gov (United States)

    Aljoumani, Basem; Kluge, Björn; sanchez, Josep; Wessolek, Gerd

    2017-04-01

    Highways and main roads are potential sources of contamination for the surrounding environment. High traffic rates result in elevated heavy metal concentrations in road runoff, soil and water seepage, which has attracted much attention in the recent past. Prediction of heavy metals transfer near the roadside into deeper soil layers are very important to prevent the groundwater pollution. This study was carried out on data of a number of lysimeters which were installed along the A115 highway (Germany) with a mean daily traffic of 90.000 vehicles per day. Three polyethylene (PE) lysimeters were installed at the A115 highway. They have the following dimensions: length 150 cm, width 100 cm, height 60 cm. The lysimeters were filled with different soil materials, which were recently used for embankment construction in Germany. With the obtained data, we will develop a time series analysis model to predict total and dissolved metal concentration in road runoff and in soil solution of the roadside embankments. The time series consisted of monthly measurements of heavy metals and was transformed to a stationary situation. Subsequently, the transformed data will be used to conduct analyses in the time domain in order to obtain the parameters of a seasonal autoregressive integrated moving average (ARIMA) model. Four phase approaches for identifying and fitting ARIMA models will be used: identification, parameter estimation, diagnostic checking, and forecasting. An automatic selection criterion, such as the Akaike information criterion, will use to enhance this flexible approach to model building

  2. Quantum-electrodynamic influences on the lifetime of metastable states

    International Nuclear Information System (INIS)

    Brenner, G.

    2007-01-01

    High-precision lifetime measurements of the metastable 1s 2 2s 2 2p 2 P 0 3/2 level in boronlike Ar XIV and the 3s 2 2p 2 P 0 3/2 level in aluminumlike Fe XIV were performed at the Heidelberg electron beam ion trap (HD-EBIT). The lifetimes were inferred by monitoring their optical decay curves resulting from the magnetic dipole (M1) transition 1s 2 2s 2 2p 2 P 0 3/2 - 2 P 0 1/2 and 3s 2 3p 2 P 0 3/2 - 2 P 0 1/2 to the ground state configuration with transition wavelengths of 441.256 nm and 530.29 nm, respectively. Possible systematic error sources were investigated by studying the dependence of the decay times of the curves on various trapping conditions with high statistical significance. A new trapping scheme for lifetime measurements at an EBIT has been applied and allowed to reach an unprecedented precision in the realm of lifetime determinations on highly charged ions. The results of 9.573(4)( +12 -5 ) ms (stat)(syst) for Ar XIV and 16.726(10)(+17) ms (stat)(syst) for Fe XIV with a relative accuracy of 0.14% and 0.13%, respectively, make these measurements for the first time sensitive to quantum electrodynamic effects like the electron anomalous magnetic moment (EAMM). The results, improving the accuracy of previous measurements by factors of 10 and 6, respectively, show a clear discrepancy of about 3σ and 4σ to the trend of existing theoretical models, which in almost all cases predict a shorter lifetime, when adjusted for the EAMM. The obvious disagreement between experimental results and the predictions points at the incompleteness of the theoretical models used. (orig.)

  3. Lifetime risks for aneurysmal subarachnoid haemorrhage: multivariable risk stratification.

    Science.gov (United States)

    Vlak, Monique H M; Rinkel, Gabriel J E; Greebe, Paut; Greving, Jacoba P; Algra, Ale

    2013-06-01

    The overall incidence of aneurysmal subarachnoid haemorrhage (aSAH) in western populations is around 9 per 100 000 person-years, which confers to a lifetime risk of around half per cent. Risk factors for aSAH are usually expressed as relative risks and suggest that absolute risks vary considerably according to risk factor profiles, but such estimates are lacking. We aimed to estimate incidence and lifetime risks of aSAH according to risk factor profiles. We used data from 250 patients admitted with aSAH and 574 sex-matched and age-matched controls, who were randomly retrieved from general practitioners files. We determined independent prognostic factors with multivariable logistic regression analyses and assessed discriminatory performance using the area under the receiver operating characteristic curve. Based on the prognostic model we predicted incidences and lifetime risks of aSAH for different risk factor profiles. The four strongest independent predictors for aSAH, namely current smoking (OR 6.0; 95% CI 4.1 to 8.6), a positive family history for aSAH (4.0; 95% CI 2.3 to 7.0), hypertension (2.4; 95% CI 1.5 to 3.8) and hypercholesterolaemia (0.2; 95% CI 0.1 to 0.4), were used in the final prediction model. This model had an area under the receiver operating characteristic curve of 0.73 (95% CI 0.69 to 0.76). Depending on sex, age and the four predictors, the incidence of aSAH ranged from 0.4/100 000 to 298/100 000 person-years and lifetime risk between 0.02% and 7.2%. The incidence and lifetime risk of aSAH in the general population varies widely according to risk factor profiles. Whether persons with high risks benefit from screening should be assessed in cost-effectiveness studies.

  4. Measurement of the neutron lifetime by counting trapped protons

    International Nuclear Information System (INIS)

    Byrne, J.; Dawber, P.G.; Spain, J.A.; Williams, A.P.; Dewey, M.S.; Gilliam, D.M.; Greene, G.L.; Lamaze, G.P.; Scott, R.D.; Pauwels, J.; Eykens, R.; Lamberty, A.

    1990-01-01

    The neutron lifetime τ n has been measured by counting decay protons stored in a Penning trap whose magnetic axis coincided with a neutron-beam axis. The result of the measurement is τ n =893.6±5.3 s, which agrees well with the value predicted by precise measurements of the β-decay asymmetry parameter A and the standard model

  5. Lifetime statistics of quantum chaos studied by a multiscale analysis

    KAUST Repository

    Di Falco, A.

    2012-04-30

    In a series of pump and probe experiments, we study the lifetime statistics of a quantum chaotic resonator when the number of open channels is greater than one. Our design embeds a stadium billiard into a two dimensional photonic crystal realized on a silicon-on-insulator substrate. We calculate resonances through a multiscale procedure that combines energy landscape analysis and wavelet transforms. Experimental data is found to follow the universal predictions arising from random matrix theory with an excellent level of agreement.

  6. The Susquehanna plant lifetime excellence program

    International Nuclear Information System (INIS)

    McNamara, R.W.

    1988-01-01

    This paper discusses how the Susquehanna plant lifetime excellence program (SPLEX) blends many of the objectives of a new managing for excellence program with plant life extension objectives to achieve excellence in the lifetime operation and availability of the two-unit Susquehanna steam electric station. Investments in lifetime excellence improvements will provide near-term, as well as plant life extension, benefits. A high-quality lifetime experience record, together with extensive, periodic technical assessments and cost-benefit analyses, will provide conclusive justification for future extensions of the unit operating licenses

  7. Fluorescence lifetime imaging of skin cancer

    Science.gov (United States)

    Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

    2011-03-01

    Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

  8. General predictive model of friction behavior regimes for metal contacts based on the formation stability and evolution of nanocrystalline surface films.

    Energy Technology Data Exchange (ETDEWEB)

    Argibay, Nicolas [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Cheng, Shengfeng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Sawyer, W. G. [Univ. of Florida, Gainesville, FL (United States); Michael, Joseph R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Chandross, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-09-01

    The prediction of macro-scale friction and wear behavior based on first principles and material properties has remained an elusive but highly desirable target for tribologists and material scientists alike. Stochastic processes (e.g. wear), statistically described parameters (e.g. surface topography) and their evolution tend to defeat attempts to establish practical general correlations between fundamental nanoscale processes and macro-scale behaviors. We present a model based on microstructural stability and evolution for the prediction of metal friction regimes, founded on recently established microstructural deformation mechanisms of nanocrystalline metals, that relies exclusively on material properties and contact stress models. We show through complementary experimental and simulation results that this model overcomes longstanding practical challenges and successfully makes accurate and consistent predictions of friction transitions for a wide range of contact conditions. This framework not only challenges the assumptions of conventional causal relationships between hardness and friction, and between friction and wear, but also suggests a pathway for the design of higher performance metal alloys.

  9. Fusion-component lifetime analysis

    International Nuclear Information System (INIS)

    Mattas, R.F.

    1982-09-01

    A one-dimensional computer code has been developed to examine the lifetime of first-wall and impurity-control components. The code incorporates the operating and design parameters, the material characteristics, and the appropriate failure criteria for the individual components. The major emphasis of the modeling effort has been to calculate the temperature-stress-strain-radiation effects history of a component so that the synergystic effects between sputtering erosion, swelling, creep, fatigue, and crack growth can be examined. The general forms of the property equations are the same for all materials in order to provide the greatest flexibility for materials selection in the code. The individual coefficients within the equations are different for each material. The code is capable of determining the behavior of a plate, composed of either a single or dual material structure, that is either totally constrained or constrained from bending but not from expansion. The code has been utilized to analyze the first walls for FED/INTOR and DEMO and to analyze the limiter for FED/INTOR

  10. Aspects of silicon bulk lifetimes

    Science.gov (United States)

    Landsberg, P. T.

    1985-01-01

    The best lifetimes attained for bulk crytalline silicon as a function of doping concentrations are analyzed. It is assumed that the dopants which set the Fermi level do not contribute to the recombination traffic which is due to the unknown defect. This defect is assumed to have two charge states: neutral and negative, the neutral defect concentration is frozen-in at some temperature T sub f. The higher doping concentrations should include the band-band Auger effect by using a generalization of the Shockley-Read-Hall (SRH) mechanism. The generalization of the SRH mechanism is discussed. This formulation gives a straightforward procedure for incorporating both band-band and band-trap Auger effects in the SRH procedure. Two related questions arise in this context: (1) it may sometimes be useful to write the steady-state occupation probability of the traps implied by SRH procedure in a form which approximates to the Fermi-Dirac distribution; and (2) the effect on the SRH mechanism of spreading N sub t levels at one energy uniformly over a range of energies is discussed.

  11. Liability and lifetime of metallic components and structures

    International Nuclear Information System (INIS)

    Tanguy, B.

    2009-12-01

    In this overview of his research activity, the author describes the ductile damage process in structures subjected to high rate loadings, notably for tank steels and gas pipeline high resistance steels. Then, he describes the cleavage fracture process in bainitic steels by means of a local fracture approach. He proposes a modelling of the Charpy v-notch impact test of the resilience-to-toughness transition during the ductile-brittle transition for bainitic steels, the developed method being used to interpret resilience and toughness tests performed on an irradiated material. He finally discusses these works, describes the current ones, and discusses research perspectives within his Nuclear Material Department

  12. Control of the Accumulation of Non-Process Elements in Pulp Mills with Bleach Filtrate Reuse: A Chemical Equilibrium Approach to Predicting the Partitioning of Metals in Pulp Mill and Bleach Plant Streams

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, W.J. Jr.; Rudie, A.W.; Schmidl, G.W.; Sinquefield, S.A.; Rorrer, G.L.; Laver, M.L.; Yantasee, W.; Ming, D.

    2000-08-01

    The overall goal of this project was to develop fundamental, experimentally based methods for predicting the solubility or organic and inorganic matter and their interactions in recycled effluent from kraft pulp mills and bleach plants. This included: characterizing the capacity of wood pulp and dissolved organic matter to bind metal ions, developing a thermodynamic database of properties needed to describe the solubility of inorganic matter in pulp mill streams, incorporation of the database into equilibrium calculation software for predicting the solubility of the metals of interest, and evaluating its capability to predict the distribution of the metals between pulp fibers, inorganic precipitates, and solution.

  13. Baselines for Lifetime of Organic Solar Cells

    DEFF Research Database (Denmark)

    Gevorgyan, Suren; Espinosa Martinez, Nieves; Ciammaruchi, Laura

    2016-01-01

    The process of accurately gauging lifetime improvements in organic photovoltaics (OPVs) or other similar emerging technologies, such as perovskites solar cells is still a major challenge. The presented work is part of a larger effort of developing a worldwide database of lifetimes that can help...

  14. Maximizing System Lifetime by Battery Scheduling

    NARCIS (Netherlands)

    Jongerden, M.R.; Haverkort, Boudewijn R.H.M.; Bohnenkamp, H.C.; Katoen, Joost P.

    2009-01-01

    The use of mobile devices is limited by the battery lifetime. Some devices have the option to connect an extra battery, or to use smart battery-packs with multiple cells to extend the lifetime. In these cases, scheduling the batteries over the load to exploit recovery properties usually extends the

  15. FUNDUS AUTOFLUORESCENCE LIFETIMES AND CENTRAL SEROUS CHORIORETINOPATHY.

    Science.gov (United States)

    Dysli, Chantal; Berger, Lieselotte; Wolf, Sebastian; Zinkernagel, Martin S

    2017-11-01

    To quantify retinal fluorescence lifetimes in patients with central serous chorioretinopathy (CSC) and to identify disease specific lifetime characteristics over the course of disease. Forty-seven participants were included in this study. Patients with central serous chorioretinopathy were imaged with fundus photography, fundus autofluorescence, optical coherence tomography, and fluorescence lifetime imaging ophthalmoscopy (FLIO) and compared with age-matched controls. Retinal autofluorescence was excited using a 473-nm blue laser light and emitted fluorescence light was detected in 2 distinct wavelengths channels (498-560 nm and 560-720 nm). Clinical features, mean retinal autofluorescence lifetimes, autofluorescence intensity, and corresponding optical coherence tomography (OCT) images were further analyzed. Thirty-five central serous chorioretinopathy patients with a mean visual acuity of 78 ETDRS letters (range, 50-90; mean Snellen equivalent: 20/32) and 12 age-matched controls were included. In the acute stage of central serous chorioretinopathy, retinal fluorescence lifetimes were shortened by 15% and 17% in the respective wavelength channels. Multiple linear regression analysis showed that fluorescence lifetimes were significantly influenced by the disease duration (P autofluorescence lifetimes, particularly in eyes with retinal pigment epithelial atrophy, were associated with poor visual acuity. This study establishes that autofluorescence lifetime changes occurring in central serous chorioretinopathy exhibit explicit patterns which can be used to estimate perturbations of the outer retinal layers with a high degree of statistical significance.

  16. Fluorescence lifetime imaging using light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Gordon T; Munro, Ian; Poher, Vincent; French, Paul M W; Neil, Mark A A [Blackett Laboratory, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Elson, Daniel S [Institute of Biomedical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Hares, Jonathan D [Kentech Instruments Ltd, Unit 9, Hall Farm Workshops, South Moreton, Didcot, Oxfordshire, OX11 9AG (United Kingdom)], E-mail: gordon.kennedy@imperial.ac.uk

    2008-05-07

    We demonstrate flexible use of low cost, high-power light emitting diodes as illumination sources for fluorescence lifetime imaging (FLIM). Both time-domain and frequency-domain techniques have been implemented at wavelengths spanning the range 450-640 nm. Additionally, we demonstrate optically sectioned fluorescence lifetime imaging by combining structured illumination with frequency-domain FLIM.

  17. Electronic computer prediction of properties of binary refractory transition metal compounds on the base of their simplificated electronic structure

    International Nuclear Information System (INIS)

    Kutolin, S.A.; Kotyukov, V.I.

    1979-01-01

    An attempt is made to obtain calculation equations of macroscopic physico-chemical properties of transition metal refractory compounds (density, melting temperature, Debye characteristic temperature, microhardness, standard formation enthalpy, thermo-emf) using the method of the regression analysis. Apart from the compound composition the argument of the regression equation is the distribution of electron bands of d-transition metals, created by the energy electron distribution in the simplified zone structure of transition metals and approximated by Chebishev polynoms, by the position of Fermi energy on the map of distribution of electron band energy depending upon the value of quasi-impulse, multiple to the first, second and third Brillouin zone for transition metals. The maximum relative error of the regressions obtained as compared with the literary data is 15-20 rel.%

  18. Assessment of trace metals pollution in estuarine sediments using SEM-AVS and ERM-ERL predictions.

    Science.gov (United States)

    Garcia, Carlos Alexandre Borges; Passos, Elisangela de Andrade; Alves, José do Patrocínio Hora

    2011-10-01

    This paper presents the distributions of the investigation of trace metals geochemistry in surface sediments of the Sergipe river estuary, northeast Brazil. Analyses were carried out by Flame or electrothermal atomic absorption spectrometry (FAAS or ETAAS). Principal component analysis was applied to results to identify any groupings among the different sampling sites. In order to determine the extent of contamination, taking into account natural variability within the region, metal concentrations were normalized relative to aluminium. Cr, Cu, Ni and Zn contamination was observed in sediments from the area receiving highest inputs of domestic wastes, while cadmium contamination occurred in sediments from the region affected by highest inflows of industrial effluents. Possible toxicity related to these metals was examined using the relationship simultaneously extracted metals/acid volatile sulfide and by comparing sediment chemical data with sediment quality guidelines ERL-ERM values. Results obtained using the two methods were in agreement and indicated that adverse effects on aquatic biota should rarely occur.

  19. Proton radioactivity lifetimes using Skyrme interactions

    International Nuclear Information System (INIS)

    Routray, T.R.; Tripathy, S.K.; Mishra, Abhishek; Basu, D.N.

    2011-01-01

    The phenomena of proton radioactivity is recent and has been possible with the advent of the radioactive ion beams facilities. The neutron deficient nuclei lying above the proton drip line has positive Q values for protons and are spontaneous proton emitters. This limits the possibilities of the creation of ever more exotic nuclei in the proton rich side of the β stability valley. Limited number of works have been done in calculating the half lives of proton emitting nuclei using different models. But calculation of lifetimes of the proton emitting nuclei using Skyrme interaction has not yet been reported. More than 110 Skyrme sets are available, constructed for different purposes, all having the common feature of giving finite nuclei ground state properties and saturation conditions in nuclear matter. Skyrme sets constructed in the late 90's, particularly the construction of SLy sets and others Skyrme sets developed thereafter, have additional care in constraining the parameters for applications to nuclear matter under extreme conditions. Stone et al. have analyzed the Skyrme sets on the basis of available constraints and have sorted out finally 27 Skyrmes sets which can be admitted for calculation of isospin rich dense nuclear matter. The objective of the work is to examine the predictions of the Skyrme sets on the half lives of the proton emitters

  20. Lifetime Evaluation of Grid-Connected PV Inverters Considering Panel Degradation Rates and Installation Sites

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2018-01-01

    Lifetime of PV inverters is affected by the installation sites related to different solar irradiance and ambient temperature profiles (also referred to as mission profiles). In fact, the installation site also affects the degradation rate of the PV panels, and thus long-term energy production...... and reliability. Prior-art lifetime analysis in PV inverters has not yet investigated the impact of PV panel degradations. This paper thus evaluates the lifetime of PV inverters considering panel degradation rates and mission profiles. Evaluations have been carried out on PV systems installed in Denmark...... and Arizona. The results reveal that the PV panel degradation rate has a considerable impact on the PV inverter lifetime, especially in the hot climate (e.g., Arizona), where the panel degrades at a faster rate. In that case, the PV inverter lifetime prediction can be deviated by 54%, if the impact of PV...

  1. Adequacy of relative and absolute risk models for lifetime risk estimate of radiation-induced cancer

    International Nuclear Information System (INIS)

    McBride, M.; Coldman, A.J.

    1988-03-01

    This report examines the applicability of the relative (multiplicative) and absolute (additive) models in predicting lifetime risk of radiation-induced cancer. A review of the epidemiologic literature, and a discussion of the mathematical models of carcinogenesis and their relationship to these models of lifetime risk, are included. Based on the available data, the relative risk model for the estimation of lifetime risk is preferred for non-sex-specific epithelial tumours. However, because of lack of knowledge concerning other determinants of radiation risk and of background incidence rates, considerable uncertainty in modelling lifetime risk still exists. Therefore, it is essential that follow-up of exposed cohorts be continued so that population-based estimates of lifetime risk are available

  2. Interatomic potential to predict the favored and optimized compositions for ternary Cu-Zr-Hf metallic glasses

    International Nuclear Information System (INIS)

    Luo, S. Y.; Cui, Y. Y.; Dai, Y.; Li, J. H.; Liu, B. X.

    2012-01-01

    Under the framework of smoothed and long range second-moment approximation of tight-binding, a realistic interatomic potential was first constructed for the Cu-Zr-Hf ternary metal system. Applying the constructed potential, Monte Carlo simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart over the entire composition triangle of the system (as a function of alloy composition). Simulations not only reveal that the origin of metallic glass formation but also determine, in the composition triangle, a quadrilateral region, within which metallic glass formation is energetically favored. It is proposed to define the energy differences between the crystalline solid solutions and disordered states as the driving force for amorphization and the corresponding calculations pinpoint an optimized composition locating at an composition of Cu 55 Zr 10 Hf 35 , around which the driving force for metallic glass formation reaches its maximum, suggesting that the ternary Cu-Zr-Hf metallic glasses designed to have the compositions around Cu 55 Zr 10 Hf 35 could be more stable than other alloys in the system. Moreover, for the Cu 55 Zr 10 Hf 35 metallic glass, the Voronoi tessellation calculations reveal some interesting features of its atomic configurations and coordination polyhedra distribution.

  3. Remaining lifetime modeling using State-of-Health estimation

    Science.gov (United States)

    Beganovic, Nejra; Söffker, Dirk

    2017-08-01

    Technical systems and system's components undergo gradual degradation over time. Continuous degradation occurred in system is reflected in decreased system's reliability and unavoidably lead to a system failure. Therefore, continuous evaluation of State-of-Health (SoH) is inevitable to provide at least predefined lifetime of the system defined by manufacturer, or even better, to extend the lifetime given by manufacturer. However, precondition for lifetime extension is accurate estimation of SoH as well as the estimation and prediction of Remaining Useful Lifetime (RUL). For this purpose, lifetime models describing the relation between system/component degradation and consumed lifetime have to be established. In this contribution modeling and selection of suitable lifetime models from database based on current SoH conditions are discussed. Main contribution of this paper is the development of new modeling strategies capable to describe complex relations between measurable system variables, related system degradation, and RUL. Two approaches with accompanying advantages and disadvantages are introduced and compared. Both approaches are capable to model stochastic aging processes of a system by simultaneous adaption of RUL models to current SoH. The first approach requires a priori knowledge about aging processes in the system and accurate estimation of SoH. An estimation of SoH here is conditioned by tracking actual accumulated damage into the system, so that particular model parameters are defined according to a priori known assumptions about system's aging. Prediction accuracy in this case is highly dependent on accurate estimation of SoH but includes high number of degrees of freedom. The second approach in this contribution does not require a priori knowledge about system's aging as particular model parameters are defined in accordance to multi-objective optimization procedure. Prediction accuracy of this model does not highly depend on estimated SoH. This model

  4. Societal and Family Lifetime Cost of Dementia: Implications for Policy.

    Science.gov (United States)

    Jutkowitz, Eric; Kane, Robert L; Gaugler, Joseph E; MacLehose, Richard F; Dowd, Bryan; Kuntz, Karen M

    2017-10-01

    To estimate the cost of dementia and the extra cost of caring for someone with dementia over the cost of caring for someone without dementia. We developed an evidence-based mathematical model to simulate disease progression for newly diagnosed individuals with dementia. Data-driven trajectories of cognition, function, and behavioral and psychological symptoms were used to model disease progression and predict costs. Using modeling, we evaluated lifetime and annual costs of individuals with dementia, compared costs of those with and without clinical features of dementia, and evaluated the effect of reducing functional decline or behavioral and psychological symptoms by 10% for 12 months (implemented when Mini-Mental State Examination score ≤21). Mathematical model. Representative simulated U.S. incident dementia cases. Value of informal care, out-of-pocket expenditures, Medicaid expenditures, and Medicare expenditures. From time of diagnosis (mean age 83), discounted total lifetime cost of care for a person with dementia was $321,780 (2015 dollars). Families incurred 70% of the total cost burden ($225,140), Medicaid accounted for 14% ($44,090), and Medicare accounted for 16% ($52,540). Costs for a person with dementia over a lifetime were $184,500 greater (86% incurred by families) than for someone without dementia. Total annual cost peaked at $89,000, and net cost peaked at $72,400. Reducing functional decline or behavioral and psychological symptoms by 10% resulted in $3,880 and $680 lower lifetime costs than natural disease progression. Dementia substantially increases lifetime costs of care. Long-lasting, effective interventions are needed to support families because they incur the most dementia cost. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  5. Investigation of soil properties influence on the heavy metals sorption by plants and possibilities for prediction of their bioaccumulation by response surface methodology

    Directory of Open Access Journals (Sweden)

    Veličković Zlate

    2016-01-01

    Full Text Available The aim of this study was to determine soil properties influence on the heavy metals sorption by vegetables which are used in the diet and possibilities for prediction of their bioaccumulation by response surface methodology (RSM. Lettuce was used as biosorbent, and cadmium (Cd and lead (Pb were used as contaminants. Lettuce is grown on compost (previously contaminated with different concentrations of Cd and Pb which pH was adjusted with different amounts of NPK fertilizers. The content of heavy metals was determined by ICP-MS. Results showed that Cd content in lettuce was below the toxic values, but Pb concentration was above allowable, which indicates that limit value for Pb is not set in accordance with the food safety regulations. It was found that the heavy metals accumulation in plants depends not only on its content in the soil, but also on the plant affinity to the specific metal, and the individual or the interactive effects of different soil properties. Through the transfer factor it was found that lettuce has a much higher affinity to Cd in relation to Pb. RSM has proved to be very good for the examination of a large number of variables with a small number of experiments.

  6. Experience with lifetime limits for EBR-II core components

    International Nuclear Information System (INIS)

    Lambert, J.D.B.; Smith, R.N.; Golden, G.H.

    1987-01-01

    The Experimental Breeder Reactor No. 2 (EBR-II) is operated for the US Department of Energy by Argonne National Laboratory and is located on the Idaho National Engineering Laboratory where most types of American reactor were originally tested. EBR-II is a complete electricity-producing power plant now in its twenty-fourth year of successful operation. During this long history the reactor has had several concurrent missions, such as demonstration of a closed Liquid-Metal Reactor (LMR) fuel cycle (1964-69); as a steady-state irradiation facility for fuels and materials (1970 onwards); for investigating effects of operational transients on fuel elements (from 1981); for research into the inherent safety aspects of metal-fueled LMR's (from 1983); and, most recently, for demonstration of the Integral Fast Reactor (IFR) concept using U-Pu-Zr fuels. This paper describes experience gained at EBR-II in defining lifetime limits for LMR core components, particularly fuel elements

  7. Geofractionation of heavy metals and application of indices for pollution prediction in paddy field soil of Tumpat, Malaysia.

    Science.gov (United States)

    Sow, Ai Yin; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir

    2013-12-01

    The present study investigates the concentration of Pb, Cd, Ni, Zn, and Cu in the paddy field soils collected from Tumpat, Kelantan. Soil samples were treated with sequential extraction to distinguish the anthropogenic and lithogenic origin of Pb, Cd, Ni, Zn, and Cu. ELFE and oxidizable-organic fractions were detected as the lowest accumulation of Pb, Cd, Ni, Zn, and Cu. Therefore, all the heavy metals examined were concentrated, particularly in resistant fraction, indicating that those heavy metals occurred and accumulated in an unavailable form. The utilization of agrochemical fertilizers and pesticides might not elevate the levels of heavy metals in the paddy field soils. In comparison, the enrichment factor and geoaccumulation index for Pb, Cd, Ni, Zn, and Cu suggest that these heavy metals have the potential to cause environmental risk, although they present abundance in resistant fraction. Therefore, a complete study should be conducted based on the paddy cycle, which in turn could provide a clear picture of heavy metals distribution in the paddy field soils.

  8. Robust D-optimal designs under correlated error, applicable invariantly for some lifetime distributions

    International Nuclear Information System (INIS)

    Das, Rabindra Nath; Kim, Jinseog; Park, Jeong-Soo

    2015-01-01

    In quality engineering, the most commonly used lifetime distributions are log-normal, exponential, gamma and Weibull. Experimental designs are useful for predicting the optimal operating conditions of the process in lifetime improvement experiments. In the present article, invariant robust first-order D-optimal designs are derived for correlated lifetime responses having the above four distributions. Robust designs are developed for some correlated error structures. It is shown that robust first-order D-optimal designs for these lifetime distributions are always robust rotatable but the converse is not true. Moreover, it is observed that these designs depend on the respective error covariance structure but are invariant to the above four lifetime distributions. This article generalizes the results of Das and Lin [7] for the above four lifetime distributions with general (intra-class, inter-class, compound symmetry, and tri-diagonal) correlated error structures. - Highlights: • This paper presents invariant robust first-order D-optimal designs under correlated lifetime responses. • The results of Das and Lin [7] are extended for the four lifetime (log-normal, exponential, gamma and Weibull) distributions. • This paper also generalizes the results of Das and Lin [7] to more general correlated error structures

  9. Nuclear Power Plant Lifetime Management Study (I)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Yull; Jeong, Ill Seok; Jang, Chang Heui; Song, Taek Ho; Song, Woo Young [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Jin, Tae Eun [Korea Power Engineering Company Consulting and Architecture Engineers, (Korea, Republic of); Kim, Woo Chul [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    As the operation-year of nuclear power plant increases and finding sites for new nuclear power plant becomes harder, a comprehensive and systematic nuclear plant lifetime management(PLIM) program including life extension has to be established for stable and safe supply of electricity. A feasibility study was conducted to systematically evaluate technical, economic and regulatory aspect of plant lifetime managements and plant life extension for Kori-1 nuclear power plant. For technical evaluation of nuclear power plant, 13 major components were selected for lifetime evaluation by screening system. structure, and components(SSCs) of the plant. It was found that except reactor pressure vessel, which needs detailed integrity analysis, and low pressure turbine, which is scheduled to be replaced, 11 out of 13 major components have sufficient service life, for more than 40 years. Because domestic rules and regulations related to license renewal has not yet been written, review on the regulatory aspect of life extensions was conducted using US NRC rules and regulations. A cooperative effort with nuclear regulatory body is needed for early completion of license renewal rules and regulations. For economic evaluation of plant lifetime extension, a computer program was developed and used. It was found that 10 to 20 year of extension operation of Kori-1 nuclear power plant was proved. Based on the results, next phase of plant lifetime management program for detailed lifetime evaluation and presenting detailed implementation schedule for plant refurbishment for lifetime extension should be followed. (author). 74 refs., figs.

  10. Three-dimensional fluorescence lifetime tomography

    International Nuclear Information System (INIS)

    Godavarty, Anuradha; Sevick-Muraca, Eva M.; Eppstein, Margaret J.

    2005-01-01

    Near-infrared fluorescence tomography using molecularly targeted lifetime-sensitive, fluorescent contrast agents have applications for early-stage cancer diagnostics. Yet, although the measurement of fluorescent lifetime imaging microscopy (FLIM) is extensively used in microscopy and spectroscopy applications, demonstration of fluorescence lifetime tomography for medical imaging is limited to two-dimensional studies. Herein, the feasibility of three-dimensional fluorescence-lifetime tomography on clinically relevant phantom volumes is established, using (i) a gain-modulated intensified charge coupled device (CCD) and modulated laser diode imaging system, (ii) two fluorescent contrast agents, e.g., Indocyanine green and 3-3'-Diethylthiatricarbocyanine iodide differing in their fluorescence lifetime by 0.62 ns, and (iii) a two stage approximate extended Kalman filter reconstruction algorithm. Fluorescence measurements of phase and amplitude were acquired on the phantom surface under different target to background fluorescence absorption (70:1, 100:1) and fluorescence lifetime (1:1, 2.1:1) contrasts at target depths of 1.4-2 cm. The Bayesian tomography algorithm was employed to obtain three-dimensional images of lifetime and absorption owing to the fluorophores

  11. Nuclear Power Plant Lifetime Management Study (I)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Yull; Jeong, Ill Seok; Jang, Chang Heui; Song, Taek Ho; Song, Woo Young [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Jin, Tae Eun [Korea Power Engineering Company Consulting and Architecture Engineers, (Korea, Republic of); Kim, Woo Chul [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-12-31

    As the operation-year of nuclear power plant increases and finding sites for new nuclear power plant becomes harder, a comprehensive and systematic nuclear plant lifetime management(PLIM) program including life extension has to be established for stable and safe supply of electricity. A feasibility study was conducted to systematically evaluate technical, economic and regulatory aspect of plant lifetime managements and plant life extension for Kori-1 nuclear power plant. For technical evaluation of nuclear power plant, 13 major components were selected for lifetime evaluation by screening system. structure, and components(SSCs) of the plant. It was found that except reactor pressure vessel, which needs detailed integrity analysis, and low pressure turbine, which is scheduled to be replaced, 11 out of 13 major components have sufficient service life, for more than 40 years. Because domestic rules and regulations related to license renewal has not yet been written, review on the regulatory aspect of life extensions was conducted using US NRC rules and regulations. A cooperative effort with nuclear regulatory body is needed for early completion of license renewal rules and regulations. For economic evaluation of plant lifetime extension, a computer program was developed and used. It was found that 10 to 20 year of extension operation of Kori-1 nuclear power plant was proved. Based on the results, next phase of plant lifetime management program for detailed lifetime evaluation and presenting detailed implementation schedule for plant refurbishment for lifetime extension should be followed. (author). 74 refs., figs.

  12. Beam-foil lifetimes of highly ionized silicon

    International Nuclear Information System (INIS)

    Traebert, E.; Heckmann, P.H.; Buttlar, H. v.

    1977-01-01

    Electronically excited states of Si ions are created by passing a 20 MeV Si 5+ beam through a thin carbon foil. The EUV-radiation (lambda = 13-61 nm) emitted by the beam is analyzed using a grazing-incidence spectrometer. From the decay curves, lifetimes of 24 low lying levels in Si VIII to Si XII and of the 4f and 5g levels of Si XI and Si XII are derived. Cascades from doubly excited states turn out to be an important contribution to the radiation observed. The lifetime values of this work are compared to theoretical data mainly of Wiese, Sinanoglu and Dankwort/Trefftz. Most experimental values agree with at least one of the theoretical values. The decay time 560 ps of the 2s2p 3 3 D 0 3 state of Si IX is clearly longer than the theoretical prediction (highest value 455 ps by Sinanoglu). (orig.) [de

  13. Statistical estimation of fast-reactor fuel-element lifetime

    International Nuclear Information System (INIS)

    Proshkin, A.A.; Likhachev, Yu.I.; Tuzov, A.N.; Zabud'ko, L.M.

    1980-01-01

    On the basis of a statistical analysis, the main parameters having a significant influence on the theoretical determination of fuel-element lifetimes in the operation of power fast reactors in steady power conditions are isolated. These include the creep and swelling of the fuel and shell materials, prolonged-plasticity lag, shell-material corrosion, gap contact conductivity, and the strain diagrams of the shell and fuel materials obtained for irradiated materials at the corresponding strain rates. By means of deeper investigation of these properties of the materials, it is possible to increase significantly the reliability of fuel-element lifetime predictions in designing fast reactors and to optimize the structure of fuel elements more correctly. The results of such calculations must obviously be taken into account in the cost-benefit analysis of projected new reactors and in choosing the optimal fuel burnup. 9 refs

  14. Quantitative fluorescence lifetime spectroscopy in turbid media: comparison of theoretical, experimental and computational methods

    International Nuclear Information System (INIS)

    Vishwanath, Karthik; Mycek, Mary-Ann; Pogue, Brian

    2002-01-01

    A Monte Carlo model developed to simulate time-resolved fluorescence propagation in a semi-infinite turbid medium was validated against previously reported theoretical and computational results. Model simulations were compared to experimental measurements of fluorescence spectra and lifetimes on tissue-simulating phantoms for single and dual fibre-optic probe geometries. Experiments and simulations using a single probe revealed that scattering-induced artefacts appeared in fluorescence emission spectra, while fluorescence lifetimes were unchanged. Although fluorescence lifetime measurements are generally more robust to scattering artefacts than are measurements of fluorescence spectra, in the dual-probe geometry scattering-induced changes in apparent lifetime were predicted both from diffusion theory and via Monte Carlo simulation, as well as measured experimentally. In all cases, the recovered apparent lifetime increased with increasing scattering and increasing source-detector separation. Diffusion theory consistently underestimated the magnitude of these increases in apparent lifetime (predicting a maximum increase of ∼15%), while Monte Carlo simulations and experiment were closely matched (showing increases as large as 30%). These results indicate that quantitative simulations of time-resolved fluorescence propagation in turbid media will be important for accurate recovery of fluorophore lifetimes in biological spectroscopy and imaging applications. (author)

  15. Applications of the KKR-DCA: A Finite-Temperature Density Functional Theory to Predict Chemical Short-Range Order Effects in Disordered Metallic Alloys

    Science.gov (United States)

    Biava, D. A.; Johnson, D. D.

    2009-03-01

    Short-range order (SRO) is ubiquitous in metallic alloys, affecting changes in their electronic, thermodynamic, mechanical, magnetic, and structural properties. For example, SRO is responsible for the yield-strength anomalies observed in Cu-Al at high temperatures, i.e., the materials is more resistant to dislocation motion at high temperature than it is at room temperature. Within the Korringa-Kohn-Rostorker (KKR) electronic-structure method, we present results using the dynamical cluster approximations (DCA) to obtain the temperature-dependent SRO in disordered alloys. We obtain the KKR-DCA SRO energetics versus local neighbor SRO parameters and minimize it at fixed temperature to predict the SRO. We show that the calculated SRO at fixed temperature compares well with available experimental results, and then correlate the results to the electronic structure. We discuss how an accurate analytic estimate can be made for the SRO in most metals due to the dependence of the grand potential on SRO.

  16. Lifetime measurement of ATF damping ring

    International Nuclear Information System (INIS)

    Okugi, T.; Hayano, H.; Kubo, K.; Naito, T.; Terunuma, N.; Urakawa, J.; Zimmermann, F.

    1998-06-01

    The purpose of the ATF damping ring is the development of technologies for producing a low emittance beam required in future linear colliders such as JLC. The lifetime of the damping ring is very short (typically a few minutes). It is limited by elastic beam-gas scattering along with a small dynamic aperture, and by single intra-beam scattering (Touschek effect). The Touschek lifetime strongly depends upon the charge density of the beam, especially, the size of the vertical emittance. In this paper, the authors report the results of beam lifetime measurements in the ATF damping ring and the estimation of the vertical emittance from these measurements

  17. Lifetime of B hadrons from CDF

    International Nuclear Information System (INIS)

    Miao, Ting.

    1996-08-01

    A review of the lifetimes of B hadrons measured by the CDF collaboration at Fermilab is presented. The data corresponds to 110 pb -1 of p anti p collisions at √s = 1.8 TeV. The inclusive B hadron lifetime is measured using a high statistics sample of B → J/ΨΧ decays. Species specific lifetimes of the B + , B 0 , B 0 s , and Λ 0 b are determined using both fully reconstructed decays and partially reconstructed decays consisting of a lepton associated with a charm hadron

  18. Models for Battery Reliability and Lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G. H.; Neubauer, J.; Pesaran, A.

    2014-03-01

    Models describing battery degradation physics are needed to more accurately understand how battery usage and next-generation battery designs can be optimized for performance and lifetime. Such lifetime models may also reduce the cost of battery aging experiments and shorten the time required to validate battery lifetime. Models for chemical degradation and mechanical stress are reviewed. Experimental analysis of aging data from a commercial iron-phosphate lithium-ion (Li-ion) cell elucidates the relative importance of several mechanical stress-induced degradation mechanisms.

  19. Statistical Models and Methods for Lifetime Data

    CERN Document Server

    Lawless, Jerald F

    2011-01-01

    Praise for the First Edition"An indispensable addition to any serious collection on lifetime data analysis and . . . a valuable contribution to the statistical literature. Highly recommended . . ."-Choice"This is an important book, which will appeal to statisticians working on survival analysis problems."-Biometrics"A thorough, unified treatment of statistical models and methods used in the analysis of lifetime data . . . this is a highly competent and agreeable statistical textbook."-Statistics in MedicineThe statistical analysis of lifetime or response time data is a key tool in engineering,

  20. Study on lifetime of C stripping foils

    International Nuclear Information System (INIS)

    Zhang Hongbin; Lu Ziwei; Zhao Yongtao; Li Zhankui; Xu Hushan; Xiao Guoqing; Wang Yuyu; Zhang Ling; Li Longcai; Fang Yan

    2007-01-01

    The carbon stripping foils can be prepared with the AC and DC arc discharge methods, or even sandwiched with AC-DC alternative layers. The lifetime of the carbon stripping foils of 19 μg/cm 2 prepared with different methods and/or structures was measured. The factors affecting the bombarding lifetime of the carbon stripping foils, especially the method of the foil preparation and the structure of the carbon stripping foils, were discussed. It is observed that the foils prepared with the DC arc discharge method have a longer bombarding lifetime than those prepared with the AC arc discharge method. (authors)

  1. Electrically induced metastability in SI-GaAs studied by positron lifetime spectroscopy

    International Nuclear Information System (INIS)

    Luo, Y.L.; Beling, C.D.; Fung, S.; Ling, C.C.; Lui, M.K.; Mui, W.K.

    2001-01-01

    Recently, a room temperature electrically induced metastability in semi-insulating (SI)-GaAs has been reported in which the normally high resistance state of SI-GaAs converts into a low resistance state when breakdown electric fields are applied to the metal/Si-GaAs/metal system. The low resistance state persists when the electric field is lowered below the breakdown bias and as such may thus be considered as metastable state of the material. To clarify whether the high field breakdown has its origins in some atomic configurational change induced through high energy electron collisions we have employed positron lifetime spectroscopy. Lifetime spectra that have been taken at the same bias in both the high current and low current phases show that the positron lifetime in the metastable state has no change within the experimental error from that of the normal state, thus suggesting that the metastability is most likely of purely electronic origin. (orig.)

  2. Positron annihilation lifetime and photoluminescence studies on single crystalline ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, A [Department of Physics, Bangabasi Morning College, 19 Rajkumar Chakraborty Sarani, Kolkata 700 009 (India); Chakrabarti, Mahuya [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India); Ray, S K [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur (India); Bhowmick, D; Sanyal, D, E-mail: dirtha@vecc.gov.in [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700064 (India)

    2011-04-20

    The room temperature positron annihilation lifetime for single crystalline ZnO has been measured as 164 {+-} 1 ps. The single component lifetime value is very close to but higher than the theoretically predicted value of {approx} 154 ps. Photoluminescence study (at 10 K) indicates the presence of hydrogen and other defects, mainly acceptor related, in the crystal. Defects related to a lower open volume than zinc vacancies, presumably a complex with two hydrogen atoms, are the major trapping sites in the sample. The bulk positron lifetime in ZnO is expected to be a little less than 164 ps.

  3. Positron annihilation lifetime and photoluminescence studies on single crystalline ZnO

    Science.gov (United States)

    Sarkar, A.; Chakrabarti, Mahuya; Ray, S. K.; Bhowmick, D.; Sanyal, D.

    2011-04-01

    The room temperature positron annihilation lifetime for single crystalline ZnO has been measured as 164 ± 1 ps. The single component lifetime value is very close to but higher than the theoretically predicted value of ~ 154 ps. Photoluminescence study (at 10 K) indicates the presence of hydrogen and other defects, mainly acceptor related, in the crystal. Defects related to a lower open volume than zinc vacancies, presumably a complex with two hydrogen atoms, are the major trapping sites in the sample. The bulk positron lifetime in ZnO is expected to be a little less than 164 ps.

  4. Positron annihilation lifetime and photoluminescence studies on single crystalline ZnO

    International Nuclear Information System (INIS)

    Sarkar, A; Chakrabarti, Mahuya; Ray, S K; Bhowmick, D; Sanyal, D

    2011-01-01

    The room temperature positron annihilation lifetime for single crystalline ZnO has been measured as 164 ± 1 ps. The single component lifetime value is very close to but higher than the theoretically predicted value of ∼ 154 ps. Photoluminescence study (at 10 K) indicates the presence of hydrogen and other defects, mainly acceptor related, in the crystal. Defects related to a lower open volume than zinc vacancies, presumably a complex with two hydrogen atoms, are the major trapping sites in the sample. The bulk positron lifetime in ZnO is expected to be a little less than 164 ps.

  5. Lifetime Estimation of Electrolytic Capacitors in Fuel Cell Power Converter at Various Confidence Levels

    DEFF Research Database (Denmark)

    Zhou, Dao; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    DC capacitors in power electronic converters are a major constraint on improvement of the power density and the reliability. In this paper, according to the degradation data of tested capacitors, the lifetime model of the component is analyzed at various confidence levels. Then, the mission profile...... based lifetime expectancy of the individual capacitor and the capacitor bank is estimated in a fuel cell backup power converter operating in both standby mode and operation mode. The lifetime prediction of the capacitor banks at different confidence levels is also obtained....

  6. Predicted energy densitites for nickel-hydrogen and silver-hydrogen cells embodying metallic hydrides for hydrogen storage

    Science.gov (United States)

    Easter, R. W.

    1974-01-01

    Simplified design concepts were used to estimate gravimetric and volumetric energy densities for metal hydrogen battery cells for assessing the characteristics of cells containing metal hydrides as compared to gaseous storage cells, and for comparing nickel cathode and silver cathode systems. The silver cathode was found to yield superior energy densities in all cases considered. The inclusion of hydride forming materials yields cells with very high volumetric energy densities that also retain gravimetric energy densities nearly as high as those of gaseous storage cells.

  7. Quasi-particle lifetime broadening in normal-superconductor junctions with UPt3

    NARCIS (Netherlands)

    deWilde, Y; Klapwijk, TM; Jansen, AGM; Heil, J; Wyder, P

    For the Andreev-reflection process of quasi-particles at a normal-metal-superconductor interface the influence of lifetime broadening of the quasi-particles on the current-voltage characteristics of NS point contacts is analyzed along the lines of the Blonder-Tinkham-Klapwijk model. The anomalous

  8. From laboratory corrosion tests to a corrosion lifetime for wood fasteners : progress and challenges

    Science.gov (United States)

    Samuel L. Zelinka; Dominique Derome; Samuel V. Glass

    2010-01-01

    Determining a “corrosion-lifetime” for fasteners embedded in wood treated with recently adopted preservative systems depends upon successfully relating results of laboratory tests to in-service conditions. In contrast to laboratory tests where metal is embedded in wood at constant temperature and moisture content, the in-service temperature and moisture content of wood...

  9. Troubles in the systematic prediction of transition metal thermochemistry with contemporary out-of-the-box methods

    KAUST Repository

    Minenkov, Yury; Chermak, Edrisse; Cavallo, Luigi

    2016-01-01

    (MUE lower 2.0 kcal/mol). Problems started with group 4 metals (Ti and Zr). Best performer for Zr complexes with a MUE of 1.8 kcal/mol, PBE0-D3, provides a MUE larger than 8 kcal/mol for Ti. DLPNO-CCSD(T) provides a reasonable MUE of 3.3 kcal/mol for Ti

  10. RDM lifetime measurements in 187Tl

    International Nuclear Information System (INIS)

    Chamoli, S.K.; Joshi, P.; Kumar, A.; Govil, I.M.; Mukherjee, G.; Singh, R.P.; Muralithar, S.; Bhowmik, R.K.

    2003-01-01

    The present work is an attempt to study the shape changes in 187 Tl through a measurement of electromagnetic transition probabilities of the high spin states. The Doppler shifted recoil distance technique was used to measure the lifetimes

  11. Improved b lifetime measurement from MAC

    International Nuclear Information System (INIS)

    Ford, W.T.

    1984-03-01

    Two recent publications, from the MAC and Mark II collaborations, have reported the somewhat surprising result that the lifetime of particles made up of b quarks is in the 1 to 2 picosecond range, or somewhat longer than the lifetimes of charm particles. Although the charm decays are favored transitions while those of b particles depend upon off-diagonal elements of the weak flavor mixing matrix, the smallness of the b decay rates in face of the large available phase space indicates that the off-diagonal elements are indeed very small. The possibility for complete determination of the mixing matrix was brought significantly nearer by the availability of the lifetime information; what is needed now is to reduce the uncertainty of the measurements, which was about 33% for both experiments. We describe here an extension of the b lifetime study with the MAC detector, incorporating some new data and improvements in the analysis. 12 references

  12. Lifetime measurements of excited Co I levels

    CERN Document Server

    Klotz, W D; Gobel, L H

    1977-01-01

    In the region of 3500 AA the lifetimes of eight excited Cobalt I levels have been measured by means of the zero field level crossing method. The measured lifetimes belong to the odd configurations 3d/sup 7/4s4p and 3d/sup 8/4p and are of the accuracy of about 5%. The hyperfine structure of levels with I not=J has to be taken into account in evaluating lifetimes from level crossing data, because the nuclear spin of the natural isotope /sup 59/Co is I=7/2. Therefore the influence of the line profile of the exciting resonance lines on the lifetimes has been investigated. The results are compared with those of other authors. Furthermore absolute oscillator strengths were calculated with known branching ratios and a new absolute scale has been established. (23 refs).

  13. Remote UV Fluorescence Lifetime Spectrometer, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to develop, demonstrate, and deliver to NASA an innovative, portable, and power efficient Remote UV Fluorescence Lifetime Spectrometer...

  14. Lifetime measurements of hadrons containing heavy quarks

    International Nuclear Information System (INIS)

    Forden, G.E.

    1985-01-01

    Recent lifetime measurements of heavy particles at PETRA and PEP are reviewed. A comparison of the methods used is given. The world averages for the lifetimes of the D 0 and D +- mesons are found to be (tau/dub D/ 0 ) - 3.97 +/- 0.3 x 10 -13 sec and (tau/dub D +-/) = 8.6 +/- 0.7 x 10 -13 sec. This difference in lifetimes is discussed in light of recent information about exclusive decays. The world average for the lifetime of bottom hadrons is determined to be (tau/sub b/) = 11.0 +/- 1.5 x 10 -13 sec and new estimates for the b quark mixing elements, absolute value V/sub bu/ and absolute value V/sub bc/, are given

  15. Lifetime measurement in {sup 195}Po

    Energy Technology Data Exchange (ETDEWEB)

    Grahn, T.; Page, R.D. [University of Liverpool, Department of Physics, Oliver Lodge Laboratory, Liverpool (United Kingdom); Dewald, A.; Jolie, J.; Melon, B.; Pissulla, T. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Greenlees, P.T.; Jakobsson, U.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Nyman, M.; Peura, P.; Rahkila, P.; Saren, J.; Scholey, C.; Sorri, J.; Uusitalo, J. [University of Jyvaeskylae, Department of Physics, P.O. Box 35, Jyvaeskylae (Finland); Kroell, T.; Kruecken, R.; Maierbeck, P. [TU Muenchen, Physik-Department E12, Garching (Germany)

    2009-03-15

    The lifetime of the 17/2{sup +} yrast state in {sup 195}Po has been measured using the recoil distance Doppler-shift technique to be {tau}=43(11) ps. The lifetime was extracted from the singles {gamma}-ray spectra obtained by using the recoil-decay tagging method. The present work provides more information of the coupling schemes, shapes and configuration mixing in neutron-deficient odd-mass Po nuclei. (orig.)

  16. The measurement of subnanosecond nuclear lifetimes

    International Nuclear Information System (INIS)

    White, D.C.S.

    1974-01-01

    This research dealt with the measurement of subnanosecond nuclear lifetimes using the pulsed beam delayed-coincidence technique. Measurements were performed on isotopes in the f7/2 shell and specifically the isotopes of titanium and vanadium. Experimental investigations were also pursued in 59 Ni and 65 Zn. Several new lifetimes were determined and confirmation was obtained for some previous values which were measured with different techniques. More information was also obtained on certain levels where previous results are in disagreement. (author)

  17. Masses and lifetimes of B hadrons

    International Nuclear Information System (INIS)

    Kkkroll, I.J.

    1996-02-01

    The latest measurements of the masses and lifetimes of weakly decaying B hadrons from experiments at e + e - and p bar p colliders are presented. These measurements include the lifetimes of the bar B o , bar B o s , B - and b baryons, as well as searches for the B c meson. The observation of B*, p-wave B mesons (B**), and excited b baryons using inclusive and exclusive B hadron reconstruction are discussed. Results on b quark flavour tagging are given

  18. Fluorescence lifetime measurement of radical ions

    International Nuclear Information System (INIS)

    Ichinose, Nobuyuki; Kinugasa, Jun-ichiro; Hagiri, Masahide; Nakayama, Toshihiro; Murakami, Hiroshi; Kishimoto, Maki; Daido, Hiroyuki

    2004-01-01

    One-photonic excitation of a charge transfer complex of hexamethoxybenzene (HMB) and nitrosonium tetrafluoroborate (NO + BF 4 - ) in acetonitrile afforded fluorescences emission from excited radical cation of HMB (HMB + *). Lifetime of the excited radical ion species was measured to be 7 ps by the pump-probe transient absorption technique. The lifetime was much shorter than that of free radical ion (63 ps), indicating the presence of an interaction between HMB + * and NO in the excited complex. (author)

  19. Λc photoproduction and lifetime measurement

    International Nuclear Information System (INIS)

    Amendolia, S.R.; Bagliesi, G.; Batignani, G.; Bertolucci, E.; Bettoni, D.; Bizetti, A.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giannetti, P.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Raso, G.; Ristori, L.; Scribano, A.; Stefanini, A.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Beck, G.A.; Bologna, G.; D'Ettorre Piazzoli, B.; Picchi, P.; Budinich, M.; Liello, F.; Milotti, E.; Rolandi, L.; Carter, J.; Green, M.G.; Landon, M.P.J.; March, P.V.; Sacks, L.; Sanjari, A.H.; Strong, J.A.; Ciocci, M.A.; Enorini, M.; Fabbri, F.L.; Laurelli, P.; Mannocchi, G.; Simonelli, L.; Spillantini, P.; Zallo, A.

    1987-01-01

    A measurement of the lifetime of the Λ c baryon photoproduced coherently of a germanium-silicon target is presented. A signal of Λ c → ΔΚ * → pKππ 0 has been observed and the two different decay diagrams for this process are compared. A sample of 9 Λ c decays give a lifetime of 1.1(+0.8-0.4)10 13 s. (orig.)

  20. Measurement of the Omega0(c) lifetime

    International Nuclear Information System (INIS)

    Iori, M.

    2007-01-01

    The authors report a precise measurement of the (Omega) c 0 lifetime. The data were taken by the SELEX (E781) experiment using 600 GeV/c Σ - , π - and p beams. The measurement has been made using 83 ± 19 reconstructed (Omega) c 0 in the (Omega) - π - π + π + and (Omega) - π + decay modes. The lifetime of the (Omega) c 0 is measured to be 65 ± 13(stat) ± 9(sys) fs

  1. The total lifetime costs of smoking

    DEFF Research Database (Denmark)

    Rasmussen, S.R.; Prescott, E.; Sørensen, T.I.A.

    2004-01-01

    Net costs of smoking in a lifetime perspective and, hence, the economic interests in antismoking policies have been questioned. It has been proposed that the health-related costs of smoking are balanced by smaller expenditure due to shorter life expectancy.......Net costs of smoking in a lifetime perspective and, hence, the economic interests in antismoking policies have been questioned. It has been proposed that the health-related costs of smoking are balanced by smaller expenditure due to shorter life expectancy....

  2. Positron lifetime studies on thorium oxide powders

    International Nuclear Information System (INIS)

    Upadhyaya, D.D.; Muraleedharan, R.V.; Sharma, B.D.

    1982-01-01

    Positron lifetime spectra have been studied for ThO 2 powders, calcined at different temperatures and having different particle sizes. Three lifetime components could be resolved, the longest component being of low intensity. An observed strong dependence on the particle size of the annihilation process and the variation of positronium diffusion constant is explained on the basis of defect density variations in these powders. (author)

  3. A lifetime prediction method based on Cumulative Flaw Length Theory

    Czech Academy of Sciences Publication Activity Database

    Boccaccini, D. N.; Maioli, M.; Cannio, M.; Dlouhý, Ivo; Romagnoli, M.; Leonelli, C.; Boccaccini, A. R.

    2012-01-01

    Roč. 32, č. 6 (2012), s. 1175-1186 ISSN 0955-2219 R&D Projects: GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : Non-destructive evaluation * Residual stress * Thermal shock resistance Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.360, year: 2012

  4. Equivalent lifetime prediction of acrylonitrile butadiene rubber for thermal aging

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. Y.; Jang, H. K. [KAERI, Taejon (Korea, Republic of); Ryu, B. H. [Dongguk Universty, Gyeongju (Korea, Republic of); Lee, C. [Chungbuk University, Cheongju (Korea, Republic of)

    2003-07-01

    Thermal degradation of acrylonitrile butadiene rubber(NBR), which is used for O-ring material as elastomeric sealed diaphragm valve in the nuclear power plants, is examined. The thermal degradation is accelerated at 130 .deg. C by arrhenius exploit method using the activation energy calculated by thermogravimetric analysis. The weight loss temperature and glass transition temperature are verified for thermally aged NBR. The relationship between dynamic mechanical properties and elongation at break are also investigated. The threshold valued of thermally aged NBR is a ten year in the change of elongation at break.

  5. Equivalent lifetime prediction of acrylonitrile butadiene rubber for thermal aging

    International Nuclear Information System (INIS)

    Kim, K. Y.; Jang, H. K.; Ryu, B. H.; Lee, C.

    2003-01-01

    Thermal degradation of acrylonitrile butadiene rubber(NBR), which is used for O-ring material as elastomeric sealed diaphragm valve in the nuclear power plants, is examined. The thermal degradation is accelerated at 130 .deg. C by arrhenius exploit method using the activation energy calculated by thermogravimetric analysis. The weight loss temperature and glass transition temperature are verified for thermally aged NBR. The relationship between dynamic mechanical properties and elongation at break are also investigated. The threshold valued of thermally aged NBR is a ten year in the change of elongation at break

  6. Positron annihilation lifetime spectroscopy of macromolecules

    International Nuclear Information System (INIS)

    Simon, G.

    1996-01-01

    Positron annihilation lifetime spectroscopy (PALS) is a technique which makes use of the anti- particle of the electron, the positron (e + ), first predicted by Dirac in 1931. This talk will concentrate on the use of PALS as a technique in characterising macromolecules. PALS has been used by various groups to evaluate many properties that one associates with free volume such as physical ageing, gas permeability, the glass transition, uptake of a solvent, crystallinity, crosslinking, molecular mobility. One area of much interest has been the use of this technique in looking at miscibility of polymer blends. In miscible blends, the interactions of the different polymers may be expected to lead to a negative free volume of mixing because of the strong attraction between the different chains. This may influence the free volume properties. Conversely, if a material is partially miscible or totally immiscible, this should influence both the size and total content of free volume. This should be related to other properties such as mechanical properties and molecular mobility, such as measured by dielectric relaxation spectroscopy. Variations on this involve copolymerization of crosslinked materials or linear thermoplastics (the ultimate 'molecular' miscibility) and this will also be discussed. Multiphase systems such as water uptake in polymers can vary polymer properties by filling molecular voids, as well as disturbing chain conformations and, in the case of polar polymers, associating with the polymer chains. The effect of polymer molecular structure on free volume - particularly in rigid polymer chains such as substituted poly(phenylenes) and liquid crystalline polymers will also be presented. Indeed, the unusual packing which arises from such anisotropic molecules leads to unusual behaviours both of the homolpolymers and subsequent liquid crystal polymer - liquid crystal polymer blends

  7. Coupled Thermo-Mechanical and Photo-Chemical Degradation Mechanisms that determine the Reliability and Operational Lifetimes for CPV Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Dauskardt, Reinhold H. [Stanford Univ., CA (United States)

    2017-04-30

    This project sought to identify and characterize the coupled intrinsic photo-chemo-mechanical degradation mechanisms that determine the reliability and operational lifetimes for CPV technologies. Over a three year period, we have completed a highly successful program which has developed quantitative metrologies and detailed physics-based degradation models, providing new insight into the fundamental reliability physics necessary for improving materials, creating accelerated testing protocols, and producing more accurate lifetime predictions. The tasks for the program were separated into two focus areas shown in the figure below. Focus Area 1, led by Reinhold Dauskardt and Warren Cai with a primary collaboration with David Miller of NREL, studied the degradation mechanisms present in encapsulant materials. Focus Area 2, led by Reinhold Dauskardt and Ryan Brock with a primary collaboration with James Ermer and Peter Hebert of Spectrolab, studied stress development and degradation within internal CPV device interfaces. Each focus area was productive, leading to several publications, including findings on the degradation of silicone encapsulant under terrestrial UV, a model for photodegradation of silicone encapsulant adhesion, quantification and process tuning of antireflective layers on CPV, and discovery of a thermal cycling degradation mechanism present in metal gridline structures.

  8. Measurements of heavy quark and lepton lifetimes

    International Nuclear Information System (INIS)

    Jaros, J.A.

    1985-02-01

    The PEP/PETRA energy range has proved to be well-suited for the study of the lifetimes of hadrons containing the b and c quarks and the tau lepton for several reasons. First, these states comprise a large fraction of the total interaction rate in e + e - annihilation and can be cleanly identified. Second, the storage rings have operated at high luminosity and so produced these exotic states copiously. And finally, thanks to the interplay of the Fermi coupling strength, the quark and lepton masses, and the beam energy, the expected decay lengths are in the 1/2 mm range and so are comparatively easy to measure. This pleasant coincidence of cleanly identified and abundant signal with potentially large effects has made possible the first measurements of two fundamental weak couplings, tau → nu/sub tau/W and b → cW. These measurements have provided a sharp test of the standard model and allowed, for the first time, the full determination of the magnitudes of the quark mixing matrix. This paper reviews the lifetime studies made at PEP during the past year. It begins with a brief review of the three detectors, DELCO, MAC and MARK II, which have reported lifetime measurements. Next it discusses two new measurements of the tau lifetime, and briefly reviews a measurement of the D 0 lifetime. Finally, it turns to measurements of the B lifetime, which are discussed in some detail. 18 references, 14 figures, 1 table

  9. Lifetimes of charm and beauty hadrons

    International Nuclear Information System (INIS)

    Bellini, G.; Dornan, P.J.

    1997-01-01

    Major breakthroughs have been achieved in the determination of the lifetimes of charm and beauty hadrons. Much larger data samples than previously have become available and new experimental devices and techniques have been developed and employed. The lifetimes of all weakly decaying singly charmed hadrons have been measured, some with an accuracy of a few percent. The difference in the shortest lifetime - τ(Ω c ) - and the longest one - τ(D + ) - is given by a factor of close to ten. The experimental status of beauty lifetimes, while less complete, has still reached a new level of quality and is now better than 5% for the commoner states. New theoretical tools, based mainly on heavy quark expansions, have been developed; they incorporate as well as transcend earlier phenomenological descriptions. The observed pattern in the charm lifetime ratios is reproduced in a semi-quantitative manner as well as could be expected; as far as the beauty lifetime ratios are concerned some problems may well be emerging. The maturity level achieved in the measurements bodes quite well for future challenges where reliable and efficient tracking of the decay vertices will be crucial. (orig.)

  10. Preliminary Empirical Models for Predicting Shrinkage, Part Geometry and Metallurgical Aspects of Ti-6Al-4V Shaped Metal Deposition Builds

    Science.gov (United States)

    Escobar-Palafox, Gustavo; Gault, Rosemary; Ridgway, Keith

    2011-12-01

    Shaped Metal Deposition (SMD) is an additive manufacturing process which creates parts layer by layer by weld depositions. In this work, empirical models that predict part geometry (wall thickness and outer diameter) and some metallurgical aspects (i.e. surface texture, portion of finer Widmanstätten microstructure) for the SMD process were developed. The models are based on an orthogonal fractional factorial design of experiments with four factors at two levels. The factors considered were energy level (a relationship between heat source power and the rate of raw material input.), step size, programmed diameter and travel speed. The models were validated using previous builds; the prediction error for part geometry was under 11%. Several relationships between the factors and responses were identified. Current had a significant effect on wall thickness; thickness increases with increasing current. Programmed diameter had a significant effect on percentage of shrinkage; this decreased with increasing component size. Surface finish decreased with decreasing step size and current.

  11. Preliminary Empirical Models for Predicting Shrinkage, Part Geometry and Metallurgical Aspects of Ti-6Al-4V Shaped Metal Deposition Builds

    International Nuclear Information System (INIS)

    Escobar-Palafox, Gustavo; Gault, Rosemary; Ridgway, Keith

    2011-01-01

    Shaped Metal Deposition (SMD) is an additive manufacturing process which creates parts layer by layer by weld depositions. In this work, empirical models that predict part geometry (wall thickness and outer diameter) and some metallurgical aspects (i.e. surface texture, portion of finer Widmanstätten microstructure) for the SMD process were developed. The models are based on an orthogonal fractional factorial design of experiments with four factors at two levels. The factors considered were energy level (a relationship between heat source power and the rate of raw material input.), step size, programmed diameter and travel speed. The models were validated using previous builds; the prediction error for part geometry was under 11%. Several relationships between the factors and responses were identified. Current had a significant effect on wall thickness; thickness increases with increasing current. Programmed diameter had a significant effect on percentage of shrinkage; this decreased with increasing component size. Surface finish decreased with decreasing step size and current.

  12. Evaluation of liquid metal protection of a limiter/divertor in fusion reactors

    International Nuclear Information System (INIS)

    Hassanein, A.M.; Smith, D.L.

    1988-01-01

    The liquid metal protection concept is proposed mainly to prolong the lifetime of a divertor or a limiter in a fusion reactor. This attractive idea for protection requires studying a wide range of problems associated with the use of liquid-metals in fusion reactors. In this work the protection by liquid-metals has concentrated on predictions of the loss rate of the film to the plasma, the operating surface temperatures required for the film, and the potential tritium inventory requirement. The effect of plasma disruptions on the liquid metal film is also evaluated. Other problems such as liquid metal compatibility with structural materials, magnetic field effects, and the effect of liquid metal contamination on plasma performance are discussed. Three candidate liquid-metals are evaluated, i.e., lithium, gallium, and tin. A wide range of reactor operating conditions valid for both near term machines (INTOR and ITER) and for the next generation commercial reactors (TPSS) are considered. This study has indicated that the evaporation rate for candidate liquid metals can be kept below the sputtering range for reasonable operating temperatures and plasma edge conditions. At higher temperatures, evaporation dominates the losses. Impurity transport calculations indicate that impurities from the plate should not reach the main plasma. One or two millimeters of liquid films can protect the structure from severe plasma disruptions. Depending on the design of the liquid metal protection system, the tritium inventory in the liquid film is predicted to be on the order of a few grams. 16 refs., 5 figs

  13. Jensen–Shannon information of the coherent system lifetime

    International Nuclear Information System (INIS)

    Asadi, Majid; Ebrahimi, Nader; Soofi, Ehsan S.; Zohrevand, Younes

    2016-01-01

    The signature of a coherent system with n components is an n-dimensional vector whose ith element is the probability that the ith failure of the components is fatal to the system. The signature depends only on the system design and provides useful tools for comparison of systems. We propose the Jensen–Shannon information (JS) criteria for comparison of systems, which is a scalar function of the signature and ranks systems based on their designs. The JS of a system is interpreted in terms of the remaining uncertainty about the system lifetime, the utility of dependence between the lifetime and the number of failures of components fatal to the system, and the Bayesian decision theory. The JS is non-negative and its minimum is attained by k-out-of-n systems, which are the least complex systems. This property offers JS as a measure of complexity of a system. Effects of expansion of a system on JS are studied. Application examples include comparisons of various sets of new systems and used but still working systems discussed in the literature. We also give an upper bound for the JS at the general level and compare it with a known upper bound. - Highlights: • Information criteria for comparing systems based on their structures are proposed. • The criteria only depend on the number of failures of its components. • The criteria rank systems based on the complexity of predicting their lifetimes. • The criteria apply to new system and system operating with failed components.

  14. Self-reported executive functioning competencies and lifetime aggression.

    Science.gov (United States)

    King, Alan R; Breen, Cody M; Russell, Tiffany D; Nerpel, Brady P; Pogalz, Colton R

    2017-05-08

    Neuropsychological research can be advanced through a better understanding of relationships between executive functioning (EF) behavioral competencies and the expression of aggressive behavior. While performance-based EF measures have been widely examined, links between self-report indices and practical real-life outcomes have not yet been established. Executive Functioning Index subscale scores in this sample (N = 579) were linked to trait hostility (Buss-Perry Aggression Questionnaire), aggression in the natural environment (Lifetime Acts of Violence Assessment), and conduct disorder symptoms prior to age 15. Significant associations were found between all of the EFI subscales (Motivational Drive, Organization, Strategic Planning, Impulse Control, and Empathy), trait aggression, and conduct disturbance. Lifetime acts of aggression were predicted by all but Organization scores. Physical injuries inflicted on other(s) were 2 to 4 times more likely to occur among respondents generating low (z < -1) EFI subscale scores. While these EFI relationships were modest in size, they are pervasive in scope. These findings provide support for the potential role of perceived EF deficits in moderating lifetime aggression.

  15. Effects of Carbonyl Bond and Metal Cluster Dissociation and Evaporation Rates on Predictions of Nanotube Production in HiPco

    Science.gov (United States)

    Scott, Carl D.; Smalley, Richard E.

    2002-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNT) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the co-formation of CO2. It is shown that the production of CO2 is significantly greater for FeCO due to its lower bond energy as compared with that ofNiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

  16. Accuracy of dielectric-dependent hybrid functionals in the prediction of optoelectronic properties of metal oxide semiconductors: a comprehensive comparison with many-body GW and experiments

    Science.gov (United States)

    Gerosa, M.; E Bottani, C.; Di Valentin, C.; Onida, G.; Pacchioni, G.

    2018-01-01

    Understanding the electronic structure of metal oxide semiconductors is crucial to their numerous technological applications, such as photoelectrochemical water splitting and solar cells. The needed experimental and theoretical knowledge goes beyond that of pristine bulk crystals, and must include the effects of surfaces and interfaces, as well as those due to the presence of intrinsic defects (e.g. oxygen vacancies), or dopants for band engineering. In this review, we present an account of the recent efforts in predicting and understanding the optoelectronic properties of oxides using ab initio theoretical methods. In particular, we discuss the performance of recently developed dielectric-dependent hybrid functionals, providing a comparison against the results of many-body GW calculations, including G 0 W 0 as well as more refined approaches, such as quasiparticle self-consistent GW. We summarize results in the recent literature for the band gap, the band level alignment at surfaces, and optical transition energies in defective oxides, including wide gap oxide semiconductors and transition metal oxides. Correlated transition metal oxides are also discussed. For each method, we describe successes and drawbacks, emphasizing the challenges faced by the development of improved theoretical approaches. The theoretical section is preceded by a critical overview of the main experimental techniques needed to characterize the optoelectronic properties of semiconductors, including absorption and reflection spectroscopy, photoemission, and scanning tunneling spectroscopy (STS).

  17. Development of a neural network model to predict distortion during the metal forming process by line heating

    OpenAIRE

    Pinzón, César; Plazaola, Carlos; Banfield, Ilka; Fong, Amaly; Vega, Adán

    2013-01-01

    In order to achieve automation of the plate forming process by line heating, it is necessary to know in advance the deformation to be obtained under specific heating conditions. Currently, different methods exist to predict deformation, but these are limited to specific applications and most of them depend on the computational capacity so that only simple structures can be analyzed. In this paper, a neural network model that can accurately predict distortions produced during the plate forming...

  18. A thermodynamic model for predicting surface melting and overheating of different crystal planes in BCC, FCC and HCP pure metallic thin films

    International Nuclear Information System (INIS)

    Jahangir, Vafa; Riahifar, Reza; Sahba Yaghmaee, Maziar

    2016-01-01

    In order to predict as well as study the surface melting phenomena in contradiction to surface overheating, a generalized thermodynamics model including the surface free energy of solid and the melt state along with the interfacial energy of solid–liquid (melt on substrate) has been introduced. In addition, the effect of different crystal structures of surfaces in fcc, bcc and hcp metals was included in surface energies as well as in the atomistic model. These considerations lead us to predict surface melting and overheating as two contradictory melting phenomena. The results of the calculation are demonstrated on the example of Pb and Al thin films in three groups of (100), (110) and (111) surface planes. Our conclusions show good agreement with experimental results and other theoretical investigations. Moreover, a computational algorithm has been developed which enables users to investigate the surface melt or overheating of single component metallic thin film with variable crystal structures and different crystalline planes. This model and developed software can be used for studying all related surface phenomena. - Highlights: • Investigating the surface melting and overheating phenomena • Effect of crystal orientations, surface energies, geometry and different atomic surface layers • Developing a computational algorithm and its related code (free-software SMSO-Ver1) • Thickness and orientation of surface plane dominate the surface melting or overheating. • Total excess surface energy as a function of thickness and temperature explains melting.

  19. A thermodynamic model for predicting surface melting and overheating of different crystal planes in BCC, FCC and HCP pure metallic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jahangir, Vafa, E-mail: vafa.jahangir@yahoo.com; Riahifar, Reza, E-mail: reza_rfr@yahoo.com; Sahba Yaghmaee, Maziar, E-mail: fkmsahba@uni-miskolc.hu

    2016-03-31

    In order to predict as well as study the surface melting phenomena in contradiction to surface overheating, a generalized thermodynamics model including the surface free energy of solid and the melt state along with the interfacial energy of solid–liquid (melt on substrate) has been introduced. In addition, the effect of different crystal structures of surfaces in fcc, bcc and hcp metals was included in surface energies as well as in the atomistic model. These considerations lead us to predict surface melting and overheating as two contradictory melting phenomena. The results of the calculation are demonstrated on the example of Pb and Al thin films in three groups of (100), (110) and (111) surface planes. Our conclusions show good agreement with experimental results and other theoretical investigations. Moreover, a computational algorithm has been developed which enables users to investigate the surface melt or overheating of single component metallic thin film with variable crystal structures and different crystalline planes. This model and developed software can be used for studying all related surface phenomena. - Highlights: • Investigating the surface melting and overheating phenomena • Effect of crystal orientations, surface energies, geometry and different atomic surface layers • Developing a computational algorithm and its related code (free-software SMSO-Ver1) • Thickness and orientation of surface plane dominate the surface melting or overheating. • Total excess surface energy as a function of thickness and temperature explains melting.

  20. Lifetime modelling for MCrAlY coatings in industrial gas turbine blades

    Directory of Open Access Journals (Sweden)

    Krukovsky Pavel

    2004-01-01

    Full Text Available A novel theoretical and experimental approach for lifetime modelling of MCrAlY coatings for stationary gas turbines has been undertaken using the Inverse Problem Solution (IPS technique. With this technique feasible experimental data acquired after a defined experimental time t e are used as input values for the model parameters estimation. In the first stage of the approach a model, based on the oxidation and diffusion processes (Fick's first and second law was assumed, which considers the Al concentration profile across the coating. The measured average Al concentration profiles in the two-phase g+b and g - regions of coating as well as base metal were used as input values for the model parameters estimation and calculational prediction of the long term diffusion and oxidation behavior of the coating was performed. The time, when the b-NiAl phase is completely consumed was assumed as the coating lifetime end. Exposure experiments were carried out with a NiCoCrAlY coating (200 micron thickness with 8% Al in air at 900 °C and 950 °C, currently up to 10000 h. The oxide scale is growing continuously and no other oxides were observed. The average and b-NiAl phase concentration profiles of Al across the coating thickness were determined by electron microprobe and image analysis systems in the initial state after 700 and 10000 h of oxidation. The concentration profile measured after 700 h was used as input values for the model parameters estimation in order to calculate the Al and b-NiAl phase concentration profiles after 10000 h. The computational forecast for 10000 h at 950 °C and 900 °C are in good agreement with the measured data. The approach was applied for NiCoCrAlY (200 micron thickness coating lifetime modelling at 950 °C and 900 °C as well as for different coating thicknesses at 950 °C.

  1. Individual lifetime pollen and nectar foraging preferences in bumble bees

    Science.gov (United States)

    Hagbery, Jessica; Nieh, James C.

    2012-10-01

    Foraging specialization plays an important role in the ability of social insects to efficiently allocate labor. However, relatively little is known about the degree to which individual bumble bees specialize on collecting nectar or pollen, when such preferences manifest, and if individuals can alter their foraging preferences in response to changes in the colony workforce. Using Bombus impatiens, we monitored all foraging visits made by every bee in multiple colonies and showed that individual foragers exhibit consistent lifetime foraging preferences. Based upon the distribution of foraging preferences, we defined three forager types (pollen specialists, nectar specialists, and generalists). In unmanipulated colonies, 16-36 % of individuals specialized (≥90 % of visits) on nectar or pollen only. On its first day of foraging, an individual's foraging choices (nectar only, pollen only, or nectar and pollen) significantly predicted its lifetime foraging preferences. Foragers that only collected pollen on their first day of foraging made 1.61- to 1.67-fold more lifetime pollen foraging visits (as a proportion of total trips) than foragers that only collected nectar on their first foraging day. Foragers were significantly larger than bees that stayed only in the nest. We also determined the effect of removing pollen specialists at early (brood present) or later (brood absent) stages in colony life. These results suggest that generalists can alter their foraging preferences in response to the loss of a small subset of foragers. Thus, bumble bees exhibit individual lifetime foraging preferences that are established early in life, but generalists may be able to adapt to colony needs.

  2. Theory of the temperature dependence of positron bulk lifetimes-implications for vacancy formation enthalpy measurements via positron experiments

    International Nuclear Information System (INIS)

    Tam, S.W.; Sinha, S.K.; Siegel, R.W.

    1977-02-01

    Temperature dependent effects, which may have a bearing on determinations of vacancy formation enthalpies in metals by positron annihilation, have been observed in certain metals. These effects have been observed to occur both at temperatures below those at which positron annihilation is most sensitive to equilibrium vacancies and at temperatures well within the vacancy-sensitive region. The effect of thermal lattice displacements on positron lifetimes in metals was investigated to help understand these phenomena

  3. Metallic ureteral stents in malignant ureteral obstruction: short-term results and radiological features predicting stent failure in patients with non-urological malignancies.

    Science.gov (United States)

    Chow, Po-Ming; Hsu, Jui-Shan; Wang, Shuo-Meng; Yu, Hong-Jheng; Pu, Yeong-Shiau; Liu, Kao-Lang

    2014-06-01

    To provide short-term result of the metallic ureteral stent in patients with malignant ureteral obstruction and identify radiological findings predicting stent failure. The records of all patients with non-urological malignant diseases who have received metallic ureteral stents from July 2009 to March 2012 for ureteral obstruction were reviewed. Stent failure was detected by clinical symptoms and imaging studies. Survival analysis was used to estimate patency rates and factors predicting stent failure. A total of 74 patients with 130 attempts of stent insertion were included. A total of 113 (86.9 %) stents were inserted successfully and 103 (91.2 %) achieved primary patency. After excluding cases without sufficient imaging data, 94 stents were included in the survival analysis. The median functional duration of the 94 stents was 6.2 months (range 3-476 days). Obstruction in abdominal ureter (p = 0.0279) and lymphatic metastasis around ureter (p = 0.0398) were risk factors for stent failure. The median functional durations of the stents for abdominal and pelvic obstructions were 4.5 months (range 3-263 days) and 6.5 months (range 4-476 days), respectively. The median durations of the stents with and without lymphatic metastasis were 5.3 months (range 4-398 days) and 7.8 months (range 31-476 days), respectively. Metallic ureteral stents are effective and safe in relieving ureteral obstructions resulting from non-urological malignancies, and abdominal ureteral obstruction and lymphatic metastasis around ureter were associated with shorter functional duration.

  4. Positron lifetime measurements as a non-destructive technique to monitor fatigue damage

    International Nuclear Information System (INIS)

    Byrne, J.G.

    1975-09-01

    In the fatigue cycling of initially hard copper, self consistent positron lifetime and x-ray particle size measurements followed the softening process and revealed a new feature which may be the final development of microvoids before fracture. In the cyclic fatigue of initially soft 4340 steel closely spaced concurrent measurements of these parameters are now in progress. For initially hard 4340 steel fatigue softening was revealed with a large positron lifetime decrease. In hydrogen embrittlement studies positron lifetime was found to be sensitive to hydrogen in an interesting way, i.e., if a specimen is already at its maximum defect density, hydrogen is trapped at some of the defects, reduce their attraction for positrons and hence cause a decrease in positron lifetime; conversely in a soft specimen, hydrogen generates more dislocation length than it can trap at (thus cancelling) hence a positron lifetime increase occurs. In electron irradiated and annealed single crystal copper 4 annealing peaks were seen at 125, 270, 400, and 650 0 K. A clear correlation between decreasing positron lifetime and increasing percent porosity in α alumina was established. This behavior is quite []he opposite to that in metals. (auth)

  5. A CMOS Luminescence Intensity and Lifetime Dual Sensor Based on Multicycle Charge Modulation.

    Science.gov (United States)

    Fu, Guoqing; Sonkusale, Sameer R

    2018-06-01

    Luminescence plays an important role in many scientific and industrial applications. This paper proposes a novel complementary metal-oxide-semiconductor (CMOS) sensor chip that can realize both luminescence intensity and lifetime sensing. To enable high sensitivity, we propose parasitic insensitive multicycle charge modulation scheme for low-light lifetime extraction benefiting from simplicity, accuracy, and compatibility with deeply scaled CMOS process. The designed in-pixel capacitive transimpedance amplifier (CTIA) based structure is able to capture the weak luminescence-induced voltage signal by accumulating photon-generated charges in 25 discrete gated 10-ms time windows and 10-μs pulsewidth. A pinned photodiode on chip with 1.04 pA dark current is utilized for luminescence detection. The proposed CTIA-based circuitry can achieve 2.1-mV/(nW/cm 2 ) responsivity and 4.38-nW/cm 2 resolution at 630 nm wavelength for intensity measurement and 45-ns resolution for lifetime measurement. The sensor chip is employed for measuring time constants and luminescence lifetimes of an InGaN-based white light-emitting diode at different wavelengths. In addition, we demonstrate accurate measurement of the lifetime of an oxygen sensitive chromophore with sensitivity to oxygen concentration of 7.5%/ppm and 6%/ppm in both intensity and lifetime domain. This CMOS-enabled oxygen sensor was then employed to test water quality from different sources (tap water, lakes, and rivers).

  6. Predictive modeling, simulation, and optimization of laser processing techniques: UV nanosecond-pulsed laser micromachining of polymers and selective laser melting of powder metals

    Science.gov (United States)

    Criales Escobar, Luis Ernesto

    One of the most frequently evolving areas of research is the utilization of lasers for micro-manufacturing and additive manufacturing purposes. The use of laser beam as a tool for manufacturing arises from the need for flexible and rapid manufacturing at a low-to-mid cost. Laser micro-machining provides an advantage over mechanical micro-machining due to the faster production times of large batch sizes and the high costs associated with specific tools. Laser based additive manufacturing enables processing of powder metals for direct and rapid fabrication of products. Therefore, laser processing can be viewed as a fast, flexible, and cost-effective approach compared to traditional manufacturing processes. Two types of laser processing techniques are studied: laser ablation of polymers for micro-channel fabrication and selective laser melting of metal powders. Initially, a feasibility study for laser-based micro-channel fabrication of poly(dimethylsiloxane) (PDMS) via experimentation is presented. In particular, the effectiveness of utilizing a nanosecond-pulsed laser as the energy source for laser ablation is studied. The results are analyzed statistically and a relationship between process parameters and micro-channel dimensions is established. Additionally, a process model is introduced for predicting channel depth. Model outputs are compared and analyzed to experimental results. The second part of this research focuses on a physics-based FEM approach for predicting the temperature profile and melt pool geometry in selective laser melting (SLM) of metal powders. Temperature profiles are calculated for a moving laser heat source to understand the temperature rise due to heating during SLM. Based on the predicted temperature distributions, melt pool geometry, i.e. the locations at which melting of the powder material occurs, is determined. Simulation results are compared against data obtained from experimental Inconel 625 test coupons fabricated at the National

  7. Plant lifetime management at Jose Cabrera NPP

    International Nuclear Information System (INIS)

    Martin, Jorge; Garcia, Piedad

    1998-01-01

    This paper presents the results obtained during the development and implementation of the Jose Cabrera NPP Lifetime Management Program according to the methodology applied in the Plant. The implementation of the Lifetime Management Program began in 1995 with the elaboration of the annual revision document 'Lifetime Management Plan', which describes the level of development of the Lifetime Management activities, the results that have been obtained during the implementation of the Program, and the schedule of the upcoming activities. The drawing up of a weighted list of 135 important components and the elaboration of 17 dossiers integrating the ageing mechanisms analysis and its corresponding evaluation, control and mitigation methods, were the result of the activities completed during 1996. A group of 62 component/degradation phenomena pairs with a high degradation risk classification has been considered within the scope of the activity 'Assessment of Maintenance Practices. Improvement Proposal', performed by the plant during 1997 and the first term of 1998 in parallel with other Lifetime Management related activities. The results obtained within this activity have revealed for the components included in the scope of the assessment that the associated degradation phenomena are practically covered by the current maintenance, inspection and testing practices. Recommendations and improvements of the maintenance practices have been particularly proposed from a technical, supporting, proceeding and documentary point of view, and currently an analysis is being made in relation to the feasibility of implementing them at the Jose Cabrera NPP. (author)

  8. Positron lifetime studies of electron irradiated copper

    International Nuclear Information System (INIS)

    Hadnagy, T.D.

    1976-01-01

    Single-crystal copper was irradiated with 4.5-MeV electrons producing simple Frenkel defects as well as a significant concentration of divacancies. Mean positron lifetime characteristics, which are sensitive to the presence of vacancies and multivacancies in copper, was monitored after isochronal anneals between 80 and 800 0 K to determine the relative change of characteristic mean lifetimes and their associated intensities. Also a study of the dependence of the mean positron lifetime on the total electron fluence was made and compared with existing theories relating these lifetimes to vacancy or multivacancy concentrations. Numerical data from curve fitting procedures using a conventional trapping model for defect-induced changes in positron lifetimes indicate that upon irradiation with 4.5-MeV electrons at 80 0 K, about 8 percent of the defects produced are divacancy units. Divacancy units appear to be several times more effective in trapping positrons than are monovacancies. Further, the experimental data suggest that the stage III annealing processes in electron-irradiated copper most probably involve the motion and removal of both monovacancies and divacancies. A conglomerate (multivacancy) unit appears to exist as a stable entity even after annealing procedures are carried out at temperatures slightly above the stage III region. Such a stable unit could serve as a nucleation center for the appearance of voids

  9. Feeding patterns of migratory and non-migratory fourth instar larvae of two coexisting Chaoborus species in an acidic and metal contaminated lake: Importance of prey ingestion rate in predicting metal bioaccumulation

    Science.gov (United States)

    Croteau, M.-N.; Hare, L.; Marcoux, P.

    2003-01-01

    We studied diel variations in the feeding habits and migratory behaviors of two coexisting Chaoborus species in an acidic and metal contaminated lake (Lake Turcotte, QC, Canada). We found that although the zooplankton community was dominated by rotifers, both Chaoborus species fed mostly on chironomids and crustaceans despite the relatively low abundance of these prey types in the lake plankton. Chaoborus americanus larvae fed on those of Chaoborus punctipennis, but not vice versa. The non-migratory species (C. americanus) fed throughout the day and night whereas the migratory species (C. punctipennis) fed only at night while in the water column. The larger-bodied C. americanus consumed more prey and had a more diverse diet than did the smaller-bodied C. punctipennis. Differences in feeding habits between the Chaoborus species inhabiting Lake Turcotte (prey biomass, prey types) likely explain in part their ability to coexist. Attempts to predict Cd in the Chaoborus species using our measurements of Cd in their prey and their prey ingestion rates met with mixed success; although we correctly predicted higher Cd concentrations for C. americanus larvae than for C. punctipennis larvae, we under-predicted absolute Cd concentrations. We suggest that studies such as ours that are based on analyses of gut contents of larvae collected at intervals of 4h or longer likely underestimate prey ingestion rates.

  10. Lifetime of heavy hypernuclei and its implications on the weak LAMBDA N interaction

    CERN Document Server

    Cassing, W; Kamys, B; Kulessa, P; Niewodniczanski, H; Ohm, H; Pysz, K; Rudy, Z; Schult, O W B; Ströher, H

    2003-01-01

    The lifetime of the LAMBDA-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield tau subLAMBDA=(145+-11) ps. This value for tau subLAMBDA is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological DELTA I=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the DELTA I=1/2 rule is discarded in the nonmesonic LAMBDA decay. (orig.)

  11. Lifetime of heavy hypernuclei and its implications on the weak ΛN interaction

    International Nuclear Information System (INIS)

    Cassing, W.; Jarczyk, L.; Kamys, B.; Kulessa, P.; Pysz, K.; Ohm, H.; Schult, O.W.B.; Stroeher, H.; Rudy, Z.

    2003-01-01

    The lifetime of the Λ-hyperon in heavy hypernuclei measured in proton-Au, -Bi and -U collisions by the COSY-13 Collaboration at COSY-Juelich has been analyzed to yield τ Λ =(145±11) ps. This value for τ Λ is compatible with the lifetime extracted from antiproton annihilation on Bi and U targets, albeit much more accurate. Theoretical models based on the meson exchange picture and assuming the validity of the phenomenological ΔI=1/2 rule predict the lifetime of heavy hypernuclei to be significantly larger (2-3 standard deviations). Such large differences indicate that at least one of the assumptions in these models is not fulfilled. A much better reproduction of the lifetimes of heavy hypernuclei is achieved in the phase space model, if the ΔI=1/2 rule is discarded in the nonmesonic Λ decay. (orig.)

  12. Variations in the electrical short-circuit current decay for recombination lifetime and velocity measurements

    Science.gov (United States)

    Jung, Tae-Won; Lindholm, Fredrik A.; Neugroschel, Arnost

    1987-01-01

    An improved measurement system for electrical short-circuit current decay is presented that extends applicability of the method to silicon solar cells having an effective lifetime as low as 1 microsec. The system uses metal/oxide/semiconductor transistors as voltage-controlled switches. Advances in theory developed here increase precision and sensitivity in the determination of the minority-carrier recombination lifetime and recombination velocity. A variation of the method, which exploits measurements made on related back-surface field and back-ohmic contact devices, further improves precision and sensitivity. The improvements are illustrated by application to 15 different silicon solar cells.

  13. Improved lifetime of microchannel-plate PMTs

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, A., E-mail: lehmann@physik.uni-erlangen.de [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Britting, A.; Eyrich, W.; Uhlig, F. [Physikalisches Institut IV, Friedrich Alexander-University of Erlangen-Nuremberg, Erlangen (Germany); Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); and others

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈6C/cm{sup 2} integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  14. Measurement of the $\\tau$ lepton lifetime

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Garrido, L; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Fidecaro, F; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    The mean lifetime of the \\tau lepton is measured in a sample of 25700 \\tau pairs collected in 1992 with the ALEPH detector at LEP. A new analysis of the 1-1 topology events is introduced. In this analysis, the dependence of the impact parameter sum distribution on the daughter track momenta is taken into account, yielding improved precision compared to other impact parameter sum methods. Three other analyses of the one- and three-prong \\tau decays are updated with increased statistics. The measured lifetime is 293.5 \\pm 3.1 \\pm 1.7 \\fs. Including previous (1989--1991) ALEPH measurements, the combined \\tau lifetime is 293.7 \\pm 2.7 \\pm 1.6 \\fs.

  15. The neutron lifetime experiment PENeLOPE

    Energy Technology Data Exchange (ETDEWEB)

    Schreyer, Wolfgang [Technische Universitaet Muenchen (Germany); Collaboration: PENeLOPE-Collaboration

    2015-07-01

    The neutron lifetime τ{sub n}=880.3±1.1 s is an important parameter in the Standard Model of particle physics and in Big Bang cosmology. Several systematic corrections of previously published results reduced the PDG world average by several σ in the last years and call for a new experiment with complementary systematics. The experiment PENeLOPE, currently under construction at the Physik-Department of Technische Universitaet Muenchen, aims to determine the neutron lifetime with a precision of 0.1 s. It will trap ultra-cold neutrons in a magneto-gravitational trap using a large superconducting magnet and will measure their lifetime by both neutron counting and online proton detection. This presentation gives an overview over the latest developments of the experiment.

  16. Assessment of the recovery annealing efficiency for VVER-1000 materials' structure reset and lifetime extension

    International Nuclear Information System (INIS)

    Gurovich, B.; Kuleshova, E.; Prikhodko, K.; Fedotova, S.

    2011-01-01

    The results of the VVER-1000 reactor pressure vessels welds studies based on the surveillance specimens sets have revealed a high embrittlement rate of steel with high nickel content compared with predicted embrittlement determined from the Russian Guide. For these critical vessels further safe operation (even during design service life) is not allowed without additional measures (recovery annealing of the VVER-1000 welds as earlier for VVER- 440). The reason is that the rate of high nickel VVER-1000 welds embrittlement is significantly higher than that is for base metal. In order to solve a problem of VVER-1000 lifetime extension recovery annealing validation and accelerated reirradiation of specimens for prolonged operation period estimation after annealing were necessary. In this work comparison of electron-microscopy fine structure studies and fractographic studies of Charpy specimens fracture surface of the VVER-1000 high nickel welds in different states were carried out. It allows estimation of the recovery annealing effect on steels structure and its behavior at further operation. It is shown that both secondary and primary irradiation causes alike radiation-induced fine structure changes: dislocation loops and nano-size precipitates. Recovery annealing leads to full dislocation loops dissolution and significant nano-size precipitates solution but not to the initial values. The rate of radiation defects and radiation-induced precipitates accumulation at reirradiation weld after recovery annealing is lower than at primary irradiation and determine the lower secondary embrittlement rate of VVER-1000 weld. (authors)

  17. DUST DESTRUCTION RATES AND LIFETIMES IN THE MAGELLANIC CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Temim, Tea; Dwek, Eli; Boyer, Martha L. [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tchernyshyov, Kirill; Meixner, Margaret [Department of Physics and Astronomy, The Johns Hopkins University, 366 Bloomberg Center, 3400 North Charles Street, Baltimore, MD 21218 (United States); Gall, Christa [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Roman-Duval, Julia, E-mail: tea.temim@nasa.gov [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2015-02-01

    The dust budget in galaxies depends on the rate at which dust grains are created in different stellar sources and destroyed by interstellar shocks. Because of their extensive wavelength coverage, proximity, and nearly face-on geometry, the Magellanic Clouds (MCs) provide a unique opportunity to study these processes in great detail. In this paper, we use the complete sample of supernova remnants (SNRs) in the MCs to calculate the lifetimes and destruction efficiencies of silicate and carbon dust. We find dust lifetimes of 22 ± 13 Myr (30 ± 17 Myr) for silicate (carbon) grains in the LMC, and 54 ± 32 Myr (72 ± 43 Myr) for silicate (carbon) grains in the SMC. The corresponding dust destruction rates are 2.3 × 10{sup –2} M {sub ☉} yr{sup –1} (5.9 × 10{sup –3} M {sub ☉} yr{sup –1}) and 3.0 × 10{sup –3} M {sub ☉} yr{sup –1} (5.6 × 10{sup –4} M {sub ☉} yr{sup –1}) for silicate (carbon) grains in the LMC and SMC, respectively. The significantly shorter lifetimes in the MCs, as compared to the Milky Way, are explained as the combined effect of their lower total dust mass and preferentially higher dust-to-gas (D2G) mass ratios in the vicinity of the SNRs. We find that the maximum dust injection rates by asymptotic giant branch stars and core collapse supernovae are an order of magnitude lower than the dust destruction rates by the SNRs, suggesting that most of the dust may be reconstituted in dense molecular clouds. We also discuss the dependence of the dust destruction rate on the local D2G mass ratio, ambient gas density, and metallicity, as well as the application of our results to other galaxies and dust evolution models.

  18. DUST DESTRUCTION RATES AND LIFETIMES IN THE MAGELLANIC CLOUDS

    International Nuclear Information System (INIS)

    Temim, Tea; Dwek, Eli; Boyer, Martha L.; Tchernyshyov, Kirill; Meixner, Margaret; Gall, Christa; Roman-Duval, Julia

    2015-01-01

    The dust budget in galaxies depends on the rate at which dust grains are created in different stellar sources and destroyed by interstellar shocks. Because of their extensive wavelength coverage, proximity, and nearly face-on geometry, the Magellanic Clouds (MCs) provide a unique opportunity to study these processes in great detail. In this paper, we use the complete sample of supernova remnants (SNRs) in the MCs to calculate the lifetimes and destruction efficiencies of silicate and carbon dust. We find dust lifetimes of 22 ± 13 Myr (30 ± 17 Myr) for silicate (carbon) grains in the LMC, and 54 ± 32 Myr (72 ± 43 Myr) for silicate (carbon) grains in the SMC. The corresponding dust destruction rates are 2.3 × 10 –2 M ☉  yr –1 (5.9 × 10 –3 M ☉  yr –1 ) and 3.0 × 10 –3 M ☉  yr –1 (5.6 × 10 –4 M ☉  yr –1 ) for silicate (carbon) grains in the LMC and SMC, respectively. The significantly shorter lifetimes in the MCs, as compared to the Milky Way, are explained as the combined effect of their lower total dust mass and preferentially higher dust-to-gas (D2G) mass ratios in the vicinity of the SNRs. We find that the maximum dust injection rates by asymptotic giant branch stars and core collapse supernovae are an order of magnitude lower than the dust destruction rates by the SNRs, suggesting that most of the dust may be reconstituted in dense molecular clouds. We also discuss the dependence of the dust destruction rate on the local D2G mass ratio, ambient gas density, and metallicity, as well as the application of our results to other galaxies and dust evolution models

  19. Measuring and predicting the dynamic effects of a confined thin metal plate pulse heated into the liquid-vapor regime

    International Nuclear Information System (INIS)

    Baxter, R.C.

    1977-01-01

    The dynamic response of a confined thin layer of lead heated rapidly and uniformly to a supercritical state was investigated. Lead targets 0.025 mm and 0.05 mm thick were contained between a thin titanium tamping layer and a thick layer of fused quartz with several different gap widths between the lead and the confining surfaces. After being heated by an electron beam for about 50 ns, lead specimens expanded to a state of approximately half liquid and half vapor. Measurements of the stress in the quartz and the velocity of the tamper produced by the expanding lead were compared with one dimensional hydrodynamic computer program predictions. Measured and predicted peak stresses in the quartz for no gaps were approximately 12 kilobars and agreed within one kilobar. Peak stresses decreased rapidly with gap size to values, at 0.02 mm gaps, of about one kilobar for the 0.025 mm lead targets and five kilobars for the 0.05 mm targets. These values were confirmed by measurements. Predictions and measurements of tamper velocity (momentum) were within 10% only when the lead and confining walls were in close contact. The observed velocities for even very small gaps were substantially below predictions. These differences are attributed primarily to separation of the liquid and vapor phases during the expansion

  20. Vibrational lifetimes of protein amide modes

    International Nuclear Information System (INIS)

    Peterson, K.A.; Rella, C.A.

    1995-01-01

    Measurement of the lifetimes of vibrational modes in proteins has been achieved with a single frequency infrared pump-probe technique using the Stanford Picosecond Free-electron Laser, These are the first direct measurements of vibrational dynamics in the polyamide structure of proteins. In this study, modes associated with the protein backbone are investigated. Results for the amide I band, which consists mainly of the stretching motion of the carbonyl unit of the amide linkage, show that relaxation from the first vibrational excited level (v=1) to the vibrational ground state (v=0) occurs within 1.5 picoseconds with apparent first order kinetics. Comparison of lifetimes for myoglobin and azurin, which have differing secondary structures, show a small but significant difference. The lifetime for the amide I band of myoglobin is 300 femtoseconds shorter than for azurin. Further measurements are in progress on other backbone vibrational modes and on the temperature dependence of the lifetimes. Comparison of vibrational dynamics for proteins with differing secondary structure and for different vibrational modes within a protein will lead to a greater understanding of energy transfer and dissipation in biological systems. In addition, these results have relevance to tissue ablation studies which have been conducted with pulsed infrared lasers. Vibrational lifetimes are necessary for calculating the rate at which the energy from absorbed infrared photons is converted to equilibrium thermal energy within the irradiated volume. The very fast vibrational lifetimes measured here indicate that mechanisms which involve direct vibrational up-pumping of the amide modes with consecutive laser pulses, leading to bond breakage or weakening, are not valid

  1. Permeability log using new lifetime measurements

    International Nuclear Information System (INIS)

    Dowling, D.J.; Boyd, J.F.; Fuchs, J.A.

    1975-01-01

    Comparative measurements of thermal neutron decay time are obtained for a formation after irradiation with a pulsed neutron source. Chloride ions in formation fluids are concentrated by the electrosmosis effect using charged poles on a well logging sonde. The formation is irradiated with fast neutrons and a first comparative measure of the thermal neutron decay time or neutron lifetime is taken. The chloride ions are then dispersed by acoustic pumping with a magnetostrictive transducer. The formation is then again irradiated with fast neutrons and a comparative measure of neutron lifetime is taken. The comparison is a function of the variation in chloride concentration between the two measurements which is related to formation permeability

  2. An approach for longer lifetime MCFCs

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Masaru; Tatsumi, Masahiko; Hayano, Takuro [MCFC Research Association, Tokyo (Japan)] [and others

    1996-12-31

    For entering into commercialization of MCFC power plants in the beginning of the 21st century, we will devote to research for increasing lifetime as long as 40,000 hours with cell performance decay rate of 0.25 %/1000hrs as the target in FY 1999. This paper will discuss on our approach for longer lifetime MCFCs through electrolyte-loss management and NiO precipitation management as well as micro-structural control of electrodes and matrix plates. Cell voltage decay rate will be estimated by simulation through series of experiments on accelerated conditions.

  3. Lifetimes of some b-flavored hadrons

    International Nuclear Information System (INIS)

    Stone, S.

    2014-06-01

    Recent measurements of lifetimes of some b-flavored hadrons are presented and interpreted in the context of theoretical models, especially the Heavy Quark Expansion. Decay widths and decay width differences in the B s 0 - B-bar s 0 system are discussed from the studies of decays into the final states J/ψK + K - , J/ψπ + π - , D s + D s - , K + K - and D s ± π ± . Lifetime measurements of the baryons Λ b 0 , Ξ b - , Ξ b 0 , and Ω b - are also shown. (author)

  4. Extension of the nuclear power plant lifetime

    International Nuclear Information System (INIS)

    Keramsi, Alain

    2011-01-01

    After a presentation of the French nuclear context (history of the reactor fleet, choice of reactor type, PWR operation principle, competitiveness, environmental performance), this Power Point presentation addresses the context and challenges of the operation lifetime (average fleet age in different countries, examples of extensions, case of the United States, what is at stake with lifetime extension, decennial visits, EDF strategy), discusses the EDF's safety objectives (definition of the three main safety functions, impact of the operation duration and of the coexistence of two generations for the safety functions), discusses how to manage the ageing phenomenon for replaceable and non-replaceable components

  5. Lifetime, money and cost-benefit analysis

    International Nuclear Information System (INIS)

    Bengtsson, G.

    1984-01-01

    The paper describes briefly many methods for explicit or implicit valuation of the loss of lifetime expectancy due to radiation exposures or other hazards. The health gain from investment in protection is compared with the health gain from a general increase in wealth. It is concluded that in many instances lifetime is valued at 1 to 10 times the gross national product produced in this time. This seems to be reasonable for rich countries whereas it may be questionable for poorer countries. Here, any investment that raises the level of living of the poorer segment of the population may have a greater effect on life expectancy. (author)

  6. Lifetimes for some excited states of sodium

    International Nuclear Information System (INIS)

    Thomas, P.; Campos, J.

    1979-01-01

    The lifetimes of some s,p and d levels of sodium have been measured by the delayed coincidence method, using a single-photon counting technique. The results are compared with the calculated values of the present work, and with other results. The lifetimes of the ns, np, and levels up to n10; of the nf levels up to n-9;and of the ng, nh,n1 and nk levels up to n-8, have been calculated and the transition probabilities of lines with origin in these levels are given. (Author) 38 refs

  7. Magnon lifetimes in terbium at low temperatures

    International Nuclear Information System (INIS)

    Bjerrum Moeller, H.; Mackintosh, A.R.

    1979-01-01

    The lifetimes of magnons propagating in the c-direction of Tb at 4.2 K have been measured by inelastic neutron scattering. In contrast to the behaviour at higher temperatures, where magnon-magnon scattering predominates, the broadening of the magnons increases towards the boundary of the single Brillouin zone, both in the acoustic and optical branches. This suggests that the scattering of the magnons by conduction electrons is important, and the observed lifetimes are consistent with a recent estimate of the magnitude of this effect. The acoustic magnons of very long wavelength behave anomalously, presumably due to dipolar interactions

  8. Measurement of the Bs0 lifetime

    Science.gov (United States)

    Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Odier, P.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Martinez, M.; Mattison, T.; Orteu, S.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Girone, M.; Hagelberg, R.; Harvey, J.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Maggi, M.; Markou, C.; Mato, P.; Meinhard, H.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Perrodo, P.; Pusztaszeri, J.-F.; Ranjard, F.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Tomalin, I. R.; Veenhof, R.; Wachsmuth, H.; Wasserbaech, S.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Barres, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Johnson, S. D.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Fouque, G.; Passalacqua, L.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; Jaffe, D. E.; Levinthal, D.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Pepe-Altarelli, M.; Salomone, S.; Colrain, P.; Ten Have, I.; Knowles, I. G.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Thorn, S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Graefe, G.; Hanke, P.; Hepp, V.; Karger, C.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Vogl, R.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Drinkard, J.; Etienne, F.; Nicod, D.; Payre, P.; Ross, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jakobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; Denis, R. St.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Kimfn 19, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Musolino, G.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Valassi, A.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Gao, Y.; Green, M. G.; Johnson, D. L.; March, P. V.; Medcalf, T.; Mir, Ll. M.; Quazi, I. S.; Strong, J. A.; Bertin, V.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Edwards, M.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Pitis, L.; Ragusa, F.; Bellantoni, L.; Chen, W.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Nachtman, J. M.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I.; Sharma, V.; Shi, Z. H.; Turk, J. D.; Walsh, A. M.; Weber, F. V.; Lan Wu, Sau; Wu, X.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1994-02-01

    The lifetime of the Bs0 has been measured in a data sample of 8890000 hadronic events recorded with the ALEPH detector at LEP. After background subtraction 30.8 ± 6.9 events are attributed to the semileptonic decay of the Bs0 to a Ds- and an opposite-sign lepton. A maximum-likelihood fit to the distribution of the proper times of these events yields a Bs0 lifetime of τBs = 1.92 -0.35+0.45 ± 0.04 ps.

  9. Prompt Neutron Lifetime for the NBSR Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, A.L.; Diamond, D.

    2012-06-24

    In preparation for the proposed conversion of the National Institute of Standards and Technology (NIST) research reactor (NBSR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, certain point kinetics parameters must be calculated. We report here values of the prompt neutron lifetime that have been calculated using three independent methods. All three sets of calculations demonstrate that the prompt neutron lifetime is shorter for the LEU fuel when compared to the HEU fuel and longer for the equilibrium end-of-cycle (EOC) condition when compared to the equilibrium startup (SU) condition for both the HEU and LEU fuels.

  10. Long-Lifetime Low-Scatter Neutron Polarization Target

    International Nuclear Information System (INIS)

    Richardson, Jonathan M.

    2004-01-01

    Polarized neutrons scattering is an important technology for characterizing magnetic and other materials. Polarized helium three (P-3He) is a novel technology for creating polarized beams and, perhaps more importantly, for the analysis of polarization in highly divergent scattered beams. Analysis of scattered beams requires specialized targets with complex geometries to ensure accurate results. Special materials and handling procedures are required to give the targets a long useful lifetime. In most cases, the targets must be shielded from stray magnetic fields from nearby equipment. SRL has developed and demonstrated hybrid targets made from glass and aluminum. We have also developed and calibrated a low-field NMR system for measuring polarization lifetimes. We have demonstrated that our low-field system is able to measure NMR signals in the presence of conducting (metallic) cell elements. We have also demonstrated a non-magnetic valve that can be used to seal the cells. We feel that these accomplishments in Phase I are sufficient to ensure a successful Phase II program. The commercial market for this technology is solid. There are over nine neutron scattering centers in the US and Canada and over 22 abroad. Currently, the US plans to build a new $1.4B scattering facility called the Spallation Neutron Source (SNS). The technology developed in this project will allow SRL to supply targets to both existing and future facilities. SRL is also involved with the application of P-3He to medical imaging

  11. Predictive factors for the failure of endoscopic stent-in-stent self-expandable metallic stent placement to treat malignant hilar biliary obstruction.

    Science.gov (United States)

    Sugimoto, Mitsuru; Takagi, Tadayuki; Suzuki, Rei; Konno, Naoki; Asama, Hiroyuki; Watanabe, Ko; Nakamura, Jun; Kikuchi, Hitomi; Waragai, Yuichi; Takasumi, Mika; Sato, Yuki; Hikichi, Takuto; Ohira, Hiromasa

    2017-09-14

    To investigate the factors predictive of failure when placing a second biliary self-expandable metallic stents (SEMSs). This study evaluated 65 patients with an unresectable malignant hilar biliary obstruction who were examined in our hospital. Sixty-two of these patients were recruited to the study and divided into two groups: the success group, which consisted of patients in whom a stent-in-stent SEMS had been placed successfully, and the failure group, which consisted of patients in whom the stent-in-stent SEMS had not been placed successfully. We compared the characteristics of the patients, the stricture state of their biliary ducts, and the implemented endoscopic retrograde cholangiopancreatography (ERCP) procedures between the two groups. The angle between the target biliary duct stricture and the first implanted SEMS was significantly larger in the failure group than in the success group. There were significantly fewer wire or dilation devices (ERCP catheter, dilator, or balloon catheter) passing the first SEMS cell in the failure group than in the success group. The cut-off value of the angle predicting stent-in-stent SEMS placement failure was 49.7 degrees according to the ROC curve (sensitivity 91.7%, specificity 61.2%). Furthermore, the angle was significantly smaller in patients with wire or dilation devices passing the first SEMS cell than in patients without wire or dilation devices passing the first SEMS cell. A large angle was identified as a predictive factor for failure of stent-in-stent SEMS placement.

  12. Buried Volume Analysis for Propene Polymerization Catalysis Promoted by Group 4 Metals: a Tool for Molecular Mass Prediction

    KAUST Repository

    Falivene, Laura; Cavallo, Luigi; Talarico, Giovanni

    2015-01-01

    A comparison of the steric properties of homogeneous single site catalysts for propene polymerization using the percentage of buried volume (%VBur) as molecular descriptor is reported. The %VBur calculated on the neutral precursors of the active species seems to be a reliable tool to explain several experimental data related to the propene insertion and to the monomer chain transfer. Interestingly, a linear correlation between the buried volume calculated for a large set of neutral precursors and the energetic difference between propagation and termination steps calculated by DFT methods is found for Group 4 metal catalysts. The “master curves” derived for Ti, Zr and Hf confirm not only that the %VBur is an appropriate molecular descriptor for the systems considered but also that it could be used as tool for a large computational screening of new ligands.

  13. Buried Volume Analysis for Propene Polymerization Catalysis Promoted by Group 4 Metals: a Tool for Molecular Mass Prediction

    KAUST Repository

    Falivene, Laura

    2015-10-02

    A comparison of the steric properties of homogeneous single site catalysts for propene polymerization using the percentage of buried volume (%VBur) as molecular descriptor is reported. The %VBur calculated on the neutral precursors of the active species seems to be a reliable tool to explain several experimental data related to the propene insertion and to the monomer chain transfer. Interestingly, a linear correlation between the buried volume calculated for a large set of neutral precursors and the energetic difference between propagation and termination steps calculated by DFT methods is found for Group 4 metal catalysts. The “master curves” derived for Ti, Zr and Hf confirm not only that the %VBur is an appropriate molecular descriptor for the systems considered but also that it could be used as tool for a large computational screening of new ligands.

  14. A search for GMSB sleptons with lifetime at ALEPH

    International Nuclear Information System (INIS)

    Jones, Luke Timothy

    2002-01-01

    A search for slepton production via the decay of pair-produced neutralinos has been performed under the assumption that the sleptons have observable lifetime in the detector before each decaying to a lepton and a gravitino. Sleptons, neutralinos and gravitinos are particles predicted by the theory of supersymmetry, and are the supersymmetric partners of the Standard Model leptons, neutral bosons and of the graviton respectively. The search was performed in 628 pb -1 of data taken by the ALEPH detector at LEP centre-of-mass energies from 189 to 208 GeV. It was motivated by general predictions of Gauge-Mediated Supersymmetry Breaking (GMSB) models in which the lightest supersymmetric particle is always the gravitino. No evidence of the process was found. Model-independent cross-section limits are quoted as a function of neutralino mass, slepton mass and slepton lifetime in the case that the neutralino branching ratios to each slepton are equal at 1/3 (the so-called slepton co-NLSP scenario) and in the case that the neutralino decays exclusively to the stau (the stau-NLSP scenario). Excluded regions in the neutralino-stau mass plane are shown for four gravitino masses under model-specific assumptions. (author)

  15. A search for GMSB sleptons with lifetime at ALEPH

    CERN Document Server

    Jones, Luke Timothy

    2001-01-01

    A search for slepton production via the decay of pair-produced neutralinos has been performed under the assumption that the sleptons have observable lifetime in the detector before each decaying to a lepton and a gravitino. Sleptons, neutralinos and gravitinos are particles predicted by the theory of supersymmetry, and are the supersymmetric partners of the Standard Model leptons, neutral bosons and of the graviton respectively. The search was performed in 628 inverse picobarns of data taken by the ALEPH detector at LEP centre-of-mass energies from 189 to 208 GeV. It was motivated by general predictions of Gauge-Mediated Supersymmetry Breaking (GMSB) models in which the lightest supersymmetric particle is always the gravitino. No evidence of the process was found. Model-independent cross-section limits are quoted as a function of neutralino mass, slepton mass and slepton lifetime in the case that the neutralino branching ratios to each slepton are equal at one third (the so-called slepton co-NLSP scenario) an...

  16. Low cycle lifetime assessment of Al2024 alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Shehzad Saleem

    2012-07-01

    The 2024-T351 aluminium alloy is extensively used for fabricating aircraft parts. This alloy shows a relatively low ductility at room temperature and is generally heat treated in various conditions to suit particular applications. The present study experimentally and numerically analyses the damage mechanism of the aforementioned alloy subjected to multi-axial stress states. The purpose of this work is to predict the cyclic lifetime of the considered alloy, based on the local approach of damage evolution using continuum damage modelling (CDM). The experimental program involves different kinds of specimens and loading conditions. According to the experimental observations, the material response of Al2024 is highly direction-dependent showing a material behaviour between ductile and brittle. In particular, in its corresponding (small transversal) S-direction, the material behaviour can be characterised as quasi-brittle. For the modelling of such a mechanical response, a novel, fully coupled isotropic ductile-brittle continuum damage mechanics model is proposed. Since the resulting model shows a large number of material parameters, an efficient, hybrid parameter identification strategy is discussed. Within this strategy, as many parameters as possible have been determined a priori by exploiting analogies to established theories (like Paris law), while the remaining free unknowns are computed by solving an optimisation problem. Comparisons between the experimentally observed and the numerically simulated lifetimes reveal the prediction capability of the proposed model. (orig.)

  17. Is the Factor-of-2 Rule Broadly Applicable for Evaluating the Prediction Accuracy of Metal-Toxicity Models?

    Science.gov (United States)

    Meyer, Joseph S; Traudt, Elizabeth M; Ranville, James F

    2018-01-01

    In aquatic toxicology, a toxicity-prediction model is generally deemed acceptable if its predicted median lethal concentrations (LC50 values) or median effect concentrations (EC50 values) are within a factor of 2 of their paired, observed LC50 or EC50 values. However, that rule of thumb is based on results from only two studies: multiple LC50 values for the fathead minnow (Pimephales promelas) exposed to Cu in one type of exposure water, and multiple EC50 values for Daphnia magna exposed to Zn in another type of exposure water. We tested whether the factor-of-2 rule of thumb also is supported in a different dataset in which D. magna were exposed separately to Cd, Cu, Ni, or Zn. Overall, the factor-of-2 rule of thumb appeared to be a good guide to evaluating the acceptability of a toxicity model's underprediction or overprediction of observed LC50 or EC50 values in these acute toxicity tests.

  18. Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system

    Science.gov (United States)

    Davis, J. W.; Cramer, B. A.

    1976-01-01

    A method of analysis was developed for predicting permanent cyclic creep deflections in stiffened panel structures. This method uses creep equations based on cyclic tensile creep tests and a computer program to predict panel deflections as a function of mission cycle. Four materials were investigated - a titanium alloy (Ti-6Al-4V), a cobalt alloy (L605), and two nickel alloys (Rene'41 and TDNiCr). Steady-state and cyclic creep response data were obtained by testing tensile specimens fabricated from thin gage sheet (0.025 and 0.63 cm nominal). Steady-state and cyclic creep equations were developed which describe creep as a function of time, temperature and load. Tests were also performed on subsize (6.35 x 30.5 cm) rib and corrugation stiffened panels. These tests were used to correlate creep responses between elemental specimens and panels. The panel response was analyzed by use of a specially written computer program.

  19. Application of the strain energy for fatigue life prediction (LCF) of metals by the energy-based criterion

    International Nuclear Information System (INIS)

    Shahram Shahrooi; Ibrahim Henk Metselaar; Zainul Huda; Ghezavati, H.R.

    2009-01-01

    Full text: In this study, the plastic strain energy under multiaxial fatigue condition has been calculated in the cyclic plasticity models by the stress-strain hysteresis loops. Then, using the results of these models, the fatigue lives in energy-based fatigue model is predicted and compared to experimental data. Moreover, a weighting factor on shear plastic work is presented to decrease the life factors in the model fatigue. (author)

  20. On the Use of Maximum Force Criteria to Predict Localised Necking in Metal Sheets under Stretch-Bending

    Directory of Open Access Journals (Sweden)

    Domingo Morales-Palma

    2017-11-01

    Full Text Available The maximum force criteria and their derivatives, the Swift and Hill criteria, have been extensively used in the past to study sheet formability. Many extensions or modifications of these criteria have been proposed to improve necking predictions under only stretching conditions. This work analyses the maximum force principle under stretch-bending conditions and develops two different approaches to predict necking. The first is a generalisation of classical maximum force criteria to stretch-bending processes. The second approach is an extension of a previous work of the authors based on critical distance concepts, suggesting that necking of the sheet is controlled by the damage of a critical material volume located at the inner side of the sheet. An analytical deformation model is proposed to characterise the stretch-bending process under plane-strain conditions. Different parameters are considered, such as the thickness reduction, the gradient of variables through the sheet thickness, the thickness stress and the anisotropy of the material. The proposed necking models have been successfully applied to predict the failure in different materials, such as steel, brass and aluminium.