WorldWideScience

Sample records for physics-based life prediction

  1. Physics-based Modeling Tools for Life Prediction and Durability Assessment of Advanced Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objectives of this program are: (1) to develop a set of physics-based modeling tools to predict the initiation of hot corrosion and to address pit and...

  2. A parametric physics based creep life prediction approach to gas turbine blade conceptual design

    Science.gov (United States)

    Smith, Marcus Edward Brockbank

    The required useful service lives of gas turbine components and parts are naturally one of the major design constraints limiting the gas turbine design space. For example, the required service life of a turbine blade limits the firing temperature in the combustor, which in turn limits the performance of the gas turbine. For a cooled turbine blade, it also determines the necessary cooling flow, which has a strong impact on the turbine efficiency. In most gas turbine design practices, the life prediction is only emphasized during or after the detailed design has been completed. Limited life prediction efforts have been made in the early design stages, but these efforts capture only a few of the necessary key factors, such as centrifugal stress. Furthermore, the early stage prediction methods are usually hard coded in the gas turbine system design tools and hidden from the system designer's view. The common failure mechanisms affecting the service life, such as creep, fatigue and oxidation, are highly sensitive to the material temperatures and/or stresses. Calculation of these temperatures and stresses requires that the geometry, material properties, and operating conditions be known; information not typically available in early stages of design. Even without awareness of the errors, the resulting inaccuracy in the life prediction may mislead the system designers when examining a design space which is bounded indirectly by the inaccurate required life constraints. Furthermore, because intensive creep lifing analysis is possible only towards the end of the design process, any errors or changes will cost the engine manufacturer significant money; money that could be saved if more comprehensive creep lifing predictions were possible in the early stages of design. A rapid, physics-based life prediction method could address this problem by enabling the system designer to investigate the design space more thoroughly and accurately. Although not meant as a final decision

  3. Physics based modeling of a series parallel battery pack for asymmetry analysis, predictive control and life extension

    Science.gov (United States)

    Ganesan, Nandhini; Basu, Suman; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Yeo, Taejung; Sohn, Dong Kee; Doo, Seokgwang

    2016-08-01

    Lithium-Ion batteries used for electric vehicle applications are subject to large currents and various operation conditions, making battery pack design and life extension a challenging problem. With increase in complexity, modeling and simulation can lead to insights that ensure optimal performance and life extension. In this manuscript, an electrochemical-thermal (ECT) coupled model for a 6 series × 5 parallel pack is developed for Li ion cells with NCA/C electrodes and validated against experimental data. Contribution of the cathode to overall degradation at various operating conditions is assessed. Pack asymmetry is analyzed from a design and an operational perspective. Design based asymmetry leads to a new approach of obtaining the individual cell responses of the pack from an average ECT output. Operational asymmetry is demonstrated in terms of effects of thermal gradients on cycle life, and an efficient model predictive control technique is developed. Concept of reconfigurable battery pack is studied using detailed simulations that can be used for effective monitoring and extension of battery pack life.

  4. Blind test of physics-based prediction of protein structures.

    Science.gov (United States)

    Shell, M Scott; Ozkan, S Banu; Voelz, Vincent; Wu, Guohong Albert; Dill, Ken A

    2009-02-01

    We report here a multiprotein blind test of a computer method to predict native protein structures based solely on an all-atom physics-based force field. We use the AMBER 96 potential function with an implicit (GB/SA) model of solvation, combined with replica-exchange molecular-dynamics simulations. Coarse conformational sampling is performed using the zipping and assembly method (ZAM), an approach that is designed to mimic the putative physical routes of protein folding. ZAM was applied to the folding of six proteins, from 76 to 112 monomers in length, in CASP7, a community-wide blind test of protein structure prediction. Because these predictions have about the same level of accuracy as typical bioinformatics methods, and do not utilize information from databases of known native structures, this work opens up the possibility of predicting the structures of membrane proteins, synthetic peptides, or other foldable polymers, for which there is little prior knowledge of native structures. This approach may also be useful for predicting physical protein folding routes, non-native conformations, and other physical properties from amino acid sequences.

  5. Prediction Uncertainty Analyses for the Combined Physically-Based and Data-Driven Models

    Science.gov (United States)

    Demissie, Y. K.; Valocchi, A. J.; Minsker, B. S.; Bailey, B. A.

    2007-12-01

    The unavoidable simplification associated with physically-based mathematical models can result in biased parameter estimates and correlated model calibration errors, which in return affect the accuracy of model predictions and the corresponding uncertainty analyses. In this work, a physically-based groundwater model (MODFLOW) together with error-correcting artificial neural networks (ANN) are used in a complementary fashion to obtain an improved prediction (i.e. prediction with reduced bias and error correlation). The associated prediction uncertainty of the coupled MODFLOW-ANN model is then assessed using three alternative methods. The first method estimates the combined model confidence and prediction intervals using first-order least- squares regression approximation theory. The second method uses Monte Carlo and bootstrap techniques for MODFLOW and ANN, respectively, to construct the combined model confidence and prediction intervals. The third method relies on a Bayesian approach that uses analytical or Monte Carlo methods to derive the intervals. The performance of these approaches is compared with Generalized Likelihood Uncertainty Estimation (GLUE) and Calibration-Constrained Monte Carlo (CCMC) intervals of the MODFLOW predictions alone. The results are demonstrated for a hypothetical case study developed based on a phytoremediation site at the Argonne National Laboratory. This case study comprises structural, parameter, and measurement uncertainties. The preliminary results indicate that the proposed three approaches yield comparable confidence and prediction intervals, thus making the computationally efficient first-order least-squares regression approach attractive for estimating the coupled model uncertainty. These results will be compared with GLUE and CCMC results.

  6. A Physically Based Analytical Model to Predict Quantized Eigen Energies and Wave Functions Incorporating Penetration Effect

    CERN Document Server

    Chowdhury, Nadim; Azim, Zubair Al; Alam, Md Hasibul; Niaz, Iftikhar Ahmad; Khosru, Quazi D M

    2014-01-01

    We propose a physically based analytical compact model to calculate Eigen energies and Wave functions which incorporates penetration effect. The model is applicable for a quantum well structure that frequently appears in modern nano-scale devices. This model is equally applicable for both silicon and III-V devices. Unlike other models already available in the literature, our model can accurately predict all the eigen energies without the inclusion of any fitting parameters. The validity of our model has been checked with numerical simulations and the results show significantly better agreement compared to the available methods.

  7. A hybrid deep neural network and physically based distributed model for river stage prediction

    Science.gov (United States)

    hitokoto, Masayuki; sakuraba, Masaaki

    2016-04-01

    We developed the real-time river stage prediction model, using the hybrid deep neural network and physically based distributed model. As the basic model, 4 layer feed-forward artificial neural network (ANN) was used. As a network training method, the deep learning technique was applied. To optimize the network weight, the stochastic gradient descent method based on the back propagation method was used. As a pre-training method, the denoising autoencoder was used. Input of the ANN model is hourly change of water level and hourly rainfall, output data is water level of downstream station. In general, the desirable input of the ANN has strong correlation with the output. In conceptual hydrological model such as tank model and storage-function model, river discharge is governed by the catchment storage. Therefore, the change of the catchment storage, downstream discharge subtracted from rainfall, can be the potent input candidate of the ANN model instead of rainfall. From this point of view, the hybrid deep neural network and physically based distributed model was developed. The prediction procedure of the hybrid model is as follows; first, downstream discharge was calculated by the distributed model, and then estimates the hourly change of catchment storage form rainfall and calculated discharge as the input of the ANN model, and finally the ANN model was calculated. In the training phase, hourly change of catchment storage can be calculated by the observed rainfall and discharge data. The developed model was applied to the one catchment of the OOYODO River, one of the first-grade river in Japan. The modeled catchment is 695 square km. For the training data, 5 water level gauging station and 14 rain-gauge station in the catchment was used. The training floods, superior 24 events, were selected during the period of 2005-2014. Prediction was made up to 6 hours, and 6 models were developed for each prediction time. To set the proper learning parameters and network

  8. A Physically Based Theoretical Model of Spore Deposition for Predicting Spread of Plant Diseases.

    Science.gov (United States)

    Isard, Scott A; Chamecki, Marcelo

    2016-03-01

    A physically based theory for predicting spore deposition downwind from an area source of inoculum is presented. The modeling framework is based on theories of turbulence dispersion in the atmospheric boundary layer and applies only to spores that escape from plant canopies. A "disease resistance" coefficient is introduced to convert the theoretical spore deposition model into a simple tool for predicting disease spread at the field scale. Results from the model agree well with published measurements of Uromyces phaseoli spore deposition and measurements of wheat leaf rust disease severity. The theoretical model has the advantage over empirical models in that it can be used to assess the influence of source distribution and geometry, spore characteristics, and meteorological conditions on spore deposition and disease spread. The modeling framework is refined to predict the detailed two-dimensional spatial pattern of disease spread from an infection focus. Accounting for the time variations of wind speed and direction in the refined modeling procedure improves predictions, especially near the inoculum source, and enables application of the theoretical modeling framework to field experiment design.

  9. Scaling Properties of Rainfall-Induced Landslides Predicted by a Physically Based Model

    CERN Document Server

    Alvioli, M; Rossi, M

    2013-01-01

    Natural landslides exhibit scaling properties, including the frequency of the size of the landslides, and the rainfall conditions responsible for landslides. Reasons for the scaling behavior of landslides are poorly known, and only a few attempts were made to describe the empirical evidences of the self-similar scaling behavior of landslides with physically based models. We investigate the possibility of using the TRIGRS code, a consolidated, physically motivated, numerical model to describe the stability conditions of natural slopes forced by rainfall, to determine the frequency of the area of the unstable slopes and the rainfall intensity-duration (I-D) conditions that result in landslides in a region.We apply TRIGRS in a portion of the Upper Tiber River Basin, Central Italy. The spatially distributed model predicts the stability conditions of individual grid cells, given the terrain and rainfall conditions. We run TRIGRS using multiple rainfall histories, and we compare the results to empirical evidences o...

  10. Physics-based enzyme design: predicting binding affinity and catalytic activity.

    Science.gov (United States)

    Sirin, Sarah; Pearlman, David A; Sherman, Woody

    2014-12-01

    Computational enzyme design is an emerging field that has yielded promising success stories, but where numerous challenges remain. Accurate methods to rapidly evaluate possible enzyme design variants could provide significant value when combined with experimental efforts by reducing the number of variants needed to be synthesized and speeding the time to reach the desired endpoint of the design. To that end, extending our computational methods to model the fundamental physical-chemical principles that regulate activity in a protocol that is automated and accessible to a broad population of enzyme design researchers is essential. Here, we apply a physics-based implicit solvent MM-GBSA scoring approach to enzyme design and benchmark the computational predictions against experimentally determined activities. Specifically, we evaluate the ability of MM-GBSA to predict changes in affinity for a steroid binder protein, catalytic turnover for a Kemp eliminase, and catalytic activity for α-Gliadin peptidase variants. Using the enzyme design framework developed here, we accurately rank the most experimentally active enzyme variants, suggesting that this approach could provide enrichment of active variants in real-world enzyme design applications.

  11. Improving Drought Monitoring and Predictions Using Physically Based Evaporative Demand Estimates

    Science.gov (United States)

    Hobbins, M. T.; Wood, A. W.; Werner, K.

    2011-12-01

    Existing drought monitors rely heavily on precipitation (Prcp) and temperature (T) data to derive moisture fluxes at the surface, often using estimates of evaporative demand (Eo) based only on T to derive actual evapotranspiration (ET) from land surface models (LSMs). An example of this is the popular Palmer Drought Severity Index (PDSI). In the analysis of drought trends and dynamics, however, the choice of Eo-driver for LSMs is crucial: it significantly affects both the direction and magnitude of trends in estimated ET and soil moisture, particularly in energy-limited areas (in water-limited areas, ET and soil moisture trends are driven by Prcp trends). All else equal, in the long term, T-based Eo measures result in declining ET estimates (i.e., drying) as T rises, whereas using more appropriate, physically based Eo estimates will more accurately reflect observations of both wetting and drying under warming. With regard to the short-term variabilities more appropriate to monitoring ongoing droughts, we contend that, given that various requirements are met, using an appropriate Eo driver (i) as a drought metric in itself, (ii) to drive drought monitors' LSMs, and (iii) in combination with short-term Eo forecasts will enhance characterization of the evaporative dynamics of ongoing drought and permit more accurate predictions of drought development. The requirements of an appropriate Eo estimate are as follows: that at operationally appropriate time and space scales Eo is diagnostic of ET (i.e., ET and Eo co-vary in a complementary fashion); that the Eo formulation and driving data produce good estimates of Eo (i.e., the model is physically based in that it combines radiative and advective drivers, and produces Eo estimates that are accurate and unbiased with respect to observations from drivers that are available with limited latency on a daily basis) and at operational spatio-temporal resolutions; and that Eo can be forecast at operational time and space scales

  12. Aircraft Conceptual Design and Risk Analysis Using Physics-Based Noise Prediction

    Science.gov (United States)

    Olson, Erik D.; Mavris, Dimitri N.

    2006-01-01

    An approach was developed which allows for design studies of commercial aircraft using physics-based noise analysis methods while retaining the ability to perform the rapid trade-off and risk analysis studies needed at the conceptual design stage. A prototype integrated analysis process was created for computing the total aircraft EPNL at the Federal Aviation Regulations Part 36 certification measurement locations using physics-based methods for fan rotor-stator interaction tones and jet mixing noise. The methodology was then used in combination with design of experiments to create response surface equations (RSEs) for the engine and aircraft performance metrics, geometric constraints and take-off and landing noise levels. In addition, Monte Carlo analysis was used to assess the expected variability of the metrics under the influence of uncertainty, and to determine how the variability is affected by the choice of engine cycle. Finally, the RSEs were used to conduct a series of proof-of-concept conceptual-level design studies demonstrating the utility of the approach. The study found that a key advantage to using physics-based analysis during conceptual design lies in the ability to assess the benefits of new technologies as a function of the design to which they are applied. The greatest difficulty in implementing physics-based analysis proved to be the generation of design geometry at a sufficient level of detail for high-fidelity analysis.

  13. Prediction of shallow landslide occurrence: Validation of a physically-based approach through a real case study.

    Science.gov (United States)

    Schilirò, Luca; Montrasio, Lorella; Scarascia Mugnozza, Gabriele

    2016-11-01

    In recent years, physically-based numerical models have frequently been used in the framework of early-warning systems devoted to rainfall-induced landslide hazard monitoring and mitigation. For this reason, in this work we describe the potential of SLIP (Shallow Landslides Instability Prediction), a simplified physically-based model for the analysis of shallow landslide occurrence. In order to test the reliability of this model, a back analysis of recent landslide events occurred in the study area (located SW of Messina, northeastern Sicily, Italy) on October 1st, 2009 was performed. The simulation results have been compared with those obtained for the same event by using TRIGRS, another well-established model for shallow landslide prediction. Afterwards, a simulation over a 2-year span period has been performed for the same area, with the aim of evaluating the performance of SLIP as early warning tool. The results confirm the good predictive capability of the model, both in terms of spatial and temporal prediction of the instability phenomena. For this reason, we recommend an operating procedure for the real-time definition of shallow landslide triggering scenarios at the catchment scale, which is based on the use of SLIP calibrated through a specific multi-methodological approach. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Predicting the Water Level Fluctuation in an Alpine Lake Using Physically Based, Artificial Neural Network, and Time Series Forecasting Models

    Directory of Open Access Journals (Sweden)

    Chih-Chieh Young

    2015-01-01

    Full Text Available Accurate prediction of water level fluctuation is important in lake management due to its significant impacts in various aspects. This study utilizes four model approaches to predict water levels in the Yuan-Yang Lake (YYL in Taiwan: a three-dimensional hydrodynamic model, an artificial neural network (ANN model (back propagation neural network, BPNN, a time series forecasting (autoregressive moving average with exogenous inputs, ARMAX model, and a combined hydrodynamic and ANN model. Particularly, the black-box ANN model and physically based hydrodynamic model are coupled to more accurately predict water level fluctuation. Hourly water level data (a total of 7296 observations was collected for model calibration (training and validation. Three statistical indicators (mean absolute error, root mean square error, and coefficient of correlation were adopted to evaluate model performances. Overall, the results demonstrate that the hydrodynamic model can satisfactorily predict hourly water level changes during the calibration stage but not for the validation stage. The ANN and ARMAX models better predict the water level than the hydrodynamic model does. Meanwhile, the results from an ANN model are superior to those by the ARMAX model in both training and validation phases. The novel proposed concept using a three-dimensional hydrodynamic model in conjunction with an ANN model has clearly shown the improved prediction accuracy for the water level fluctuation.

  15. Physics-Based Predictions for Coherent Change Detection Using X-Band Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Mark Preiss

    2005-12-01

    Full Text Available A theoretical model is developed to describe the interferometric coherency between pairs of SAR images of rough soil surfaces. The model is derived using a dyadic form for surface reflectivity in the Kirchhoff approximation. This permits the combination of Kirchhoff theory and spotlight synthetic aperture radar (SAR image formation theory. The resulting model is used to describe the interferometric coherency between pairs of SAR images of rough soil surfaces. The theoretical model is applied to SAR images formed before and after surface changes observed by a repeat-pass SAR system. The change in surface associated with a tyre track following vehicle passage is modelled and SAR coherency estimates are obtained. Predicted coherency distributions for both the change and no-change scenarios are used to estimate receiver operator curves for the detection of the changes using a high-resolution, X-band SAR system.

  16. Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach

    Directory of Open Access Journals (Sweden)

    S. Raia

    2014-03-01

    of several model runs obtained varying the input parameters are analyzed statistically, and compared to the original (deterministic model output. The comparison suggests an improvement of the predictive power of the model of about 10% and 16% in two small test areas, that is, the Frontignano (Italy and the Mukilteo (USA areas. We discuss the computational requirements of TRIGRS-P to determine the potential use of the numerical model to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides in very large areas, extending for several hundreds or thousands of square kilometers. Parallel execution of the code using a simple process distribution and the message passing interface (MPI on multi-processor machines was successful, opening the possibly of testing the use of TRIGRS-P for the operational forecasting of rainfall-induced shallow landslides over large regions.

  17. Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach

    Directory of Open Access Journals (Sweden)

    S. Raia

    2013-02-01

    the input parameters are analyzed statistically, and compared to the original (deterministic model output. The comparison suggests an improvement of the predictive power of the model of about 10% and 16% in two small test areas, i.e. the Frontignano (Italy and the Mukilteo (USA areas, respectively. We discuss the computational requirements of TRIGRS-P to determine the potential use of the numerical model to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides in very large areas, extending for several hundreds or thousands of square kilometers. Parallel execution of the code using a simple process distribution and the Message Passing Interface (MPI on multi-processor machines was successful, opening the possibly of testing the use of TRIGRS-P for the operational forecasting of rainfall-induced shallow landslides over large regions.

  18. Improving predictive power of physically based rainfall-induced shallow landslide models: a probablistic approach

    Science.gov (United States)

    Raia, S.; Alvioli, M.; Rossi, M.; Baum, R.L.; Godt, J.W.; Guzzetti, F.

    2013-01-01

    are analyzed statistically, and compared to the original (deterministic) model output. The comparison suggests an improvement of the predictive power of the model of about 10% and 16% in two small test areas, i.e. the Frontignano (Italy) and the Mukilteo (USA) areas, respectively. We discuss the computational requirements of TRIGRS-P to determine the potential use of the numerical model to forecast the spatial and temporal occurrence of rainfall-induced shallow landslides in very large areas, extending for several hundreds or thousands of square kilometers. Parallel execution of the code using a simple process distribution and the Message Passing Interface (MPI) on multi-processor machines was successful, opening the possibly of testing the use of TRIGRS-P for the operational forecasting of rainfall-induced shallow landslides over large regions.

  19. A predictive estimation method for carbon dioxide transport by data-driven modeling with a physically-based data model.

    Science.gov (United States)

    Jeong, Jina; Park, Eungyu; Han, Weon Shik; Kim, Kue-Young; Jun, Seong-Chun; Choung, Sungwook; Yun, Seong-Taek; Oh, Junho; Kim, Hyun-Jun

    2017-09-27

    In this study, a data-driven method for predicting CO2 leaks and associated concentrations from geological CO2 sequestration is developed. Several candidate models are compared based on their reproducibility and predictive capability for CO2 concentration measurements from the Environment Impact Evaluation Test (EIT) site in Korea. Based on the data mining results, a one-dimensional solution of the advective-dispersive equation for steady flow (i.e., Ogata-Banks solution) is found to be most representative for the test data, and this model is adopted as the data model for the developed method. In the validation step, the method is applied to estimate future CO2 concentrations with the reference estimation by the Ogata-Banks solution, where a part of earlier data is used as the training dataset. From the analysis, it is found that the ensemble mean of multiple estimations based on the developed method shows high prediction accuracy relative to the reference estimation. In addition, the majority of the data to be predicted are included in the proposed quantile interval, which suggests adequate representation of the uncertainty by the developed method. Therefore, the incorporation of a reasonable physically-based data model enhances the prediction capability of the data-driven model. The proposed method is not confined to estimations of CO2 concentration and may be applied to various real-time monitoring data from subsurface sites to develop automated control, management or decision-making systems. Copyright © 2017. Published by Elsevier B.V.

  20. Stream temperature prediction in ungauged basins: review of recent approaches and description of a new physically-based analytical model

    Science.gov (United States)

    Gallice, A.; Schaefli, B.; Lehning, M.; Parlange, M. P.; Huwald, H.

    2015-04-01

    The development of stream temperature regression models at regional scales has regained some popularity over the past years. These models are used to predict stream temperature in ungauged catchments to assess the impact of human activities or climate change on riverine fauna over large spatial areas. A comprehensive literature review presented in this study shows that the temperature metrics predicted by the majority of models correspond to yearly aggregates, such as the popular annual maximum weekly mean temperature (MWMT). As a consequence, current models are often unable to predict the annual cycle of stream temperature, nor can the majority of them forecast the interannual variation of stream temperature. This study presents a new model to estimate the monthly mean stream temperature of ungauged rivers over multiple years in an Alpine country (Switzerland). Contrary to the models developed to date, which mostly rely upon statistical regression to express stream temperature as a function of physiographic and climatic variables, this one rests upon the analytical solution to a simplified version of the energy-balance equation over an entire stream network. This physically-based approach presents some advantages: (1) the functional form linking stream temperature to the predictor variables is directly obtained from first principles, (2) the spatial extent over which the predictor variables are averaged naturally arises during model development, and (3) the regression coefficients can be interpreted from a physical point of view - their values can therefore be constrained to remain within plausible bounds. The evaluation of the model over a new freely available data set shows that the monthly mean stream temperature curve can be reproduced with a root mean square error of ±1.3 °C, which is similar in precision to the predictions obtained with a multi-linear regression model. We illustrate through a simple example how the physical basis of the model can be used

  1. Programming Useful Life Prediction (PULP) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurately predicting Remaining Useful Life (RUL) provides significant benefits—it increases safety and reduces financial and labor resource requirements....

  2. Service life prediction and cementitious composites

    DEFF Research Database (Denmark)

    Stoklund Larsen, E.

    The present Ph.D.thesis describes and discusses the applicability of a systematic methodology recommended by CIB W80/RILEM-PSL for sevice life prediction. The report describes the most important inherent and environmental factors affecting the service life of structures of cementitious composites....... On the basis of this discription of factors and experience from a test programme described in SBI Report 222, Service life prediction and fibre reinforced cementitious composites, the applicabillity of the CIB/RILEM methodology is discussed....

  3. Life Cycle Assessment of Vehicle Lightweighting: A Physics-Based Model To Estimate Use-Phase Fuel Consumption of Electrified Vehicles.

    Science.gov (United States)

    Kim, Hyung Chul; Wallington, Timothy J

    2016-10-18

    Assessing the life-cycle benefits of vehicle lightweighting requires a quantitative description of mass-induced fuel consumption (MIF) and fuel reduction values (FRVs). We have extended our physics-based model of MIF and FRVs for internal combustion engine vehicles (ICEVs) to electrified vehicles (EVs) including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). We illustrate the utility of the model by calculating MIFs and FRVs for 37 EVs and 13 ICEVs. BEVs have much smaller MIF and FRVs, both in the range 0.04-0.07 Le/(100 km 100 kg), than those for ICEVs which are in the ranges 0.19-0.32 and 0.16-0.22 L/(100 km 100 kg), respectively. The MIF and FRVs for HEVs and PHEVs mostly lie between those for ICEVs and BEVs. Powertrain resizing increases the FRVs for ICEVs, HEVs and PHEVs. Lightweighting EVs is less effective in reducing greenhouse gas emissions than lightweighting ICEVs, however the benefits differ substantially for different vehicle models. The physics-based approach outlined here enables model specific assessments for ICEVs, HEVs, PHEVs, and BEVs required to determine the optimal strategy for maximizing the life-cycle benefits of lightweighting the light-duty vehicle fleet.

  4. Evaluation of Physically-based Model’s Predictive Skill for Hurricane-triggered Landslides: Case Study in North Carolina and Indonesia

    Science.gov (United States)

    Liao, Z.; Hong, Y.; Fukuoka, H.; Sassa, K.

    2009-12-01

    The key to advancing the predictability of rainfall-triggered landslides is to use physically-based, slope-stability models that simulate the dynamical response of the subsurface moisture to the spatiotemporal variability of rainfall in complex terrain. In the first study we quantitatively evaluate the spatiotemporal predictability of a Matlab version of TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability Analysis) in the Blue Ridge Mountains of Macon County, North Carolina where Hurricane Ivan triggered widespread landslides in September, 2004. A high-resolution Digital Elevation Model (DEM) (6-meter LiDAR), USGS STATSGO soil database, and NOAA/NWS combined radar and gauge precipitation are used as inputs to the model. A local landslide inventory database from the North Carolina Department of Transportation is used to evaluate the model’s predictive skill for the landslide locations and timing over a 30-hour period of Hurricane Ivan’s passage. This study shows that TRIGRS demonstrates acceptable skill for landslide occurrences within a 120-meter radius. Real-time predictions with this model offer the potential to serve as a landslide warning system in areas where accurate rainfall forecasts and detailed field data are available. In the second study, a prototype early warning system has been developed to predict typhoon-induced shallow landslides over Java Island, Indonesia. The system utilizes a newly developed physically-based model that accounts for the contribution of rainfall infiltration and partial saturation to the shear strength of the soil in topographically complex catchments. geomorphological data are primarily based on a 30-meter ASTER DEM and 1-km soil maps, where precipitation forcing comes from satellite-based TRMM nowcasts and Weather Research Forecasting (WRF) forecasts. Model performance has been evaluated using a local landslide inventory, and it shows potential for predicting future typhoon-triggered landslides.

  5. LIFE PREDICTION APPROACH FOR RANDOM MULTIAXIAL FATIGUE

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Wang Dejun

    2005-01-01

    According to the concept of critical plane, a life prediction approach for random multiaxial fatigue is presented. First, the critical plane under the multiaxial random loading is determined based on the concept of the weight-averaged maximum shear strain direction. Then the shear and normal strain histories on the determined critical plane are calculated and taken as the subject of multiaxial load simplifying and multiaxial cycle counting. Furthermore, a multiaxial fatigue life prediction model including the parameters resulted from multiaxial cycle counting is presented and applied to calculating the fatigue damage generated from each cycle. Finally, the cumulative damage is added up using Miner's linear rule, and the fatigue prediction life is given. The experiments under multiaxial loading blocks are used for the verification of the proposed method. The prediction has a good correction with the experimental results.

  6. Predicting the remaining service life of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, J.F.

    1991-11-01

    Nuclear power plants are providing, currently, about 17 percent of the U.S. electricity and many of these plants are approaching their licensed life of 40 years. The U.S. Nuclear Regulatory Commission and the Department of Energy`s Oak Ridge National Laboratory are carrying out a program to develop a methodology for assessing the remaining safe-life of the concrete components and structures in nuclear power plants. This program has the overall objective of identifying potential structural safety issues, as well as acceptance criteria, for use in evaluations of nuclear power plants for continued service. The National Institute of Standards and Technology (NIST) is contributing to this program by identifying and analyzing methods for predicting the remaining life of in-service concrete materials. This report examines the basis for predicting the remaining service lives of concrete materials of nuclear power facilities. Methods for predicting the service life of new and in-service concrete materials are analyzed. These methods include (1) estimates based on experience, (2) comparison of performance, (3) accelerated testing, (4) stochastic methods, and (5) mathematical modeling. New approaches for predicting the remaining service lives of concrete materials are proposed and recommendations for their further development given. Degradation processes are discussed based on considerations of their mechanisms, likelihood of occurrence, manifestations, and detection. They include corrosion, sulfate attack, alkali-aggregate reactions, frost attack, leaching, radiation, salt crystallization, and microbiological attack.

  7. Operational life prediction on gating image intensifier

    Science.gov (United States)

    Dong, Yu-hui; Shen, Zhi-guo; Li, Zhong-li

    2009-07-01

    Operational life is one of the important parameters to evaluate second and super second generation image intensifiers. It can be used not only to monitor manufacturing technique in product line, then the technology on photocathode processing, MCP degassing and MCP producing can be adjusted promptly, but also to eliminate the image intensifiers which have hidden risk on operational life as early as possible. Recently gating image intensifiers are used widely, method to estimate the operational life of gating image intensifier related to its practical operate mode and working condition need to be established urgently. The least square method to analyze the operational life test data in product line was introduced in this paper. Now the data can be analyzed with convenient statistic analyze function on Excel. Using "worksheet function" and "chart wizard" and "data analysis" on Excel to do the least square method calculation, spreadsheets are established to do complex data calculation with worksheet functions. Based on them, formulas to monitor the technology parameters were derived, and the conclusion that the operational life was only related to the decrease slope of photocathode exponential fit curve was made. The decrease slope of photocathode sensitivity exponential fit curve and the decrease percent of the exponential fit photocathode sensitivity can be used to evaluate the qualification of the operational life rapidly. The mathematic models for operational life prediction on image intensifier and gating image intensifier are established respectively based on the acceptable values of the decrease percent of the exponential fit photocathode sensitivity and the expecting signal to noise ratio. The equations predicting the operational life related to duty cycle and input light level on gating image intensifier were derived, and the relationship between them were discussed too. The theory foundation were made herein, so the user can select proper gating image

  8. How Much Can the Total Aleatory Variability of Empirical Ground Motion Prediction Equations Be Reduced Using Physics-Based Earthquake Simulations?

    Science.gov (United States)

    Jordan, T. H.; Wang, F.; Graves, R. W.; Callaghan, S.; Olsen, K. B.; Cui, Y.; Milner, K. R.; Juve, G.; Vahi, K.; Yu, J.; Deelman, E.; Gill, D.; Maechling, P. J.

    2015-12-01

    Ground motion prediction equations (GMPEs) in common use predict the logarithmic intensity of ground shaking, lnY, as a deterministic value, lnYpred(x), conditioned on a set of explanatory variables x plus a normally distributed random variable with a standard deviation σT. The latter accounts for the unexplained variability in the ground motion data used to calibrate the GMPE and is typically 0.5-0.7 in natural log units. Reducing this residual or "aleatory" variability is a high priority for seismic hazard analysis, because the probabilities of exceedance at high Y values go up rapidly with σT. adding costs to the seismic design of critical facilities to account for the prediction uncertainty. However, attempts to decrease σT by incorporating more explanatory variables to the GMPEs have been largely unsuccessful (e.g., Strasser et al., SRL, 2009). An alternative is to employ physics-based earthquake simulations that properly account for source directivity, basin effects, directivity-basin coupling, and other 3D complexities. We have explored the theoretical limits of this approach through an analysis of large (> 108) ensembles of 3D synthetic seismograms generated for the Los Angeles region by SCEC's CyberShake project using the new tool of averaging-based factorization (ABF, Wang & Jordan, BSSA, 2014). The residual variance obtained by applying GMPEs to the CyberShake dataset matches the frequency-dependence of σT obtained for the GMPE calibration dataset. The ABF analysis allows us to partition this variance into uncorrelated components representing source, path, and site effects. We show that simulations can potentially reduce σT by about one-third, which could lower the exceedance probabilities for high hazard levels at fixed x by orders of magnitude. Realizing this gain in forecasting probability would have a broad impact on risk-reduction strategies, especially for critical facilities such as large dams, nuclear power plants, and energy transportation

  9. 3-D or median map? Earthquake scenario ground-motion maps from physics-based models versus maps from ground-motion prediction equations

    Science.gov (United States)

    Porter, K.

    2015-12-01

    There are two common ways to create a ground-motion map for a hypothetical earthquake: using ground motion prediction equations (by far the more common of the two) and using 3-D physics-based modeling. The former is very familiar to engineers, the latter much less so, and the difference can present a problem because engineers tend to trust the familiar and distrust novelty. Maps for essentially the same hypothetical earthquake using the two different methods can look very different, while appearing to present the same information. Using one or the other can lead an engineer or disaster planner to very different estimates of damage and risk. The reasons have to do with depiction of variability, spatial correlation of shaking, the skewed distribution of real-world shaking, and the upward-curving relationship between shaking and damage. The scientists who develop the two kinds of map tend to specialize in one or the other and seem to defend their turf, which can aggravate the problem of clearly communicating with engineers.The USGS Science Application for Risk Reduction's (SAFRR) HayWired scenario has addressed the challenge of explaining to engineers the differences between the two maps, and why, in a disaster planning scenario, one might want to use the less-familiar 3-D map.

  10. Early Adolescent Affect Predicts Later Life Outcomes.

    Science.gov (United States)

    Kansky, Jessica; Allen, Joseph P; Diener, Ed

    2016-07-01

    Subjective well-being as a predictor for later behavior and health has highlighted its relationship to health, work performance, and social relationships. However, the majority of such studies neglect the developmental nature of well-being in contributing to important changes across the transition to adulthood. To examine the potential role of subjective well-being as a long-term predictor of critical life outcomes, we examined indicators of positive and negative affect at age 14 as predictors of relationship, adjustment, self-worth, and career outcomes a decade later at ages 23 to 25, controlling for family income and gender. We utilised multi-informant methods including reports from the target participant, close friends, and romantic partners in a demographically diverse community sample of 184 participants. Early adolescent positive affect predicted fewer relationship problems (less self-reported and partner-reported conflict, and greater friendship attachment as rated by close peers) and healthy adjustment to adulthood (lower levels of depression, anxiety, and loneliness). It also predicted positive work functioning (higher levels of career satisfaction and job competence) and increased self-worth. Negative affect did not significantly predict any of these important life outcomes. In addition to predicting desirable mean levels of later outcomes, early positive affect predicted beneficial changes across time in many outcomes. The findings extend early research on the beneficial outcomes of subjective well-being by having an earlier assessment of well-being, including informant reports in measuring a large variety of outcome variables, and by extending the findings to a lower socioeconomic group of a diverse and younger sample. The results highlight the importance of considering positive affect as an important component of subjective well-being distinct from negative affect. © 2016 The International Association of Applied Psychology.

  11. Complementing data-driven and physically-based approaches for predictive morphologic modeling: Results and implication from the Red River Basin, Vietnam

    Science.gov (United States)

    Schmitt, R. J.; Bernardi, D.; Bizzi, S.; Castelletti, A.; Soncini-Sessa, R.

    2013-12-01

    sediment balance over an extended time-horizon (>15 yrs.), upstream impoundments induce a much more rapid adaptation (1-5 yrs.). The applicability of the ANN as predictive model was evaluated by comparing its results with a traditional, 1D bed evolution model. The next decade's morphologic evolution under an ensemble of scenarios, considering uncertainties in climatic change, socio-economic development and upstream reservoir release policies was derived from both models. The ANN greatly outperforms the 1D model in computational requirements and presents a powerful tool for effective assessment of scenario ensembles and quantification of uncertainties in river hydro-morphology. In contrast, the processes-based model provides detailed, spatio-temporally distributed outputs and validation of the ANN's results for selected scenarios. We conclude that the application of both approaches constitutes a mutually enriching strategy for modern, quantitative catchment management. We argue that physically based modeling can have specific spatial and temporal constrains (e.g. in terms of identifying key drivers and associated temporal and spatial domains) and that linking physically-based with data-driven approaches largely increases the potential for including hydro-morphology into basin-scale water resource management.

  12. A survey on life prediction of equipment

    Directory of Open Access Journals (Sweden)

    Hu Changhua

    2015-02-01

    Full Text Available Once in the hands of end users, such durable equipment as spacecraft, aircraft, ships, automobiles, computers, etc. are in a state of debugging, working or storage. In either state, availability, reliability and super-efficiency are the ultimate goals, which have been achieved through constant monitoring as well as regular, preventive, routine and corrective maintenance. Although some advanced instruments can visualize certain invisible malfunctioning phenomena into visible ones, deeply hidden troubles cannot be found unless monitoring and testing data are addressed using tools that process the data statistically, analytically and mathematically. Some state-of-the-art trouble-shooting and life-predicting techniques and approaches are introduced in this paper.

  13. A survey on life prediction of equipment

    Institute of Scientific and Technical Information of China (English)

    Hu Changhua; Zhou Zhijie; Zhang Jianxun; Si Xiaosheng

    2015-01-01

    Once in the hands of end users, such durable equipment as spacecraft, aircraft, ships, automobiles, computers, etc. are in a state of debugging, working or storage. In either state, avail-ability, reliability and super-efficiency are the ultimate goals, which have been achieved through constant monitoring as well as regular, preventive, routine and corrective maintenance. Although some advanced instruments can visualize certain invisible malfunctioning phenomena into visible ones, deeply hidden troubles cannot be found unless monitoring and testing data are addressed using tools that process the data statistically, analytically and mathematically. Some state-of-the-art trouble-shooting and life-predicting techniques and approaches are introduced in this paper.

  14. Prediction Approach to Life on Wing for Civil Aeroengine

    Institute of Scientific and Technical Information of China (English)

    RONG Xiang; ZUO Hong-fu; ZHANG Hai-jun

    2008-01-01

    To reduce engine maintenance cost and support safe operation, a prediction method of engine life on wing was proposed. This method is a kind of regression model which is a function of the condition monitoring and failure data. Key causes of engine removals were analyzed, and the life limit due to performance deterioration was predicted by proportional hazards model. Then the scheduled removal causes were considered as constraints of engine life to predicte the final life on wing. Application of the proposed prediction method to the case of CF6-80C2A5 engine fleet in an airline proved its effectiveness.

  15. Life Prediction of Large Lithium-Ion Battery Packs with Active and Passive Balancing

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ying [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zane, Regan [Utah State University; Anderson, Dyche [Ford Motor Company

    2017-07-03

    Lithium-ion battery packs take a major part of large-scale stationary energy storage systems. One challenge in reducing battery pack cost is to reduce pack size without compromising pack service performance and lifespan. Prognostic life model can be a powerful tool to handle the state of health (SOH) estimate and enable active life balancing strategy to reduce cell imbalance and extend pack life. This work proposed a life model using both empirical and physical-based approaches. The life model described the compounding effect of different degradations on the entire cell with an empirical model. Then its lower-level submodels considered the complex physical links between testing statistics (state of charge level, C-rate level, duty cycles, etc.) and the degradation reaction rates with respect to specific aging mechanisms. The hybrid approach made the life model generic, robust and stable regardless of battery chemistry and application usage. The model was validated with a custom pack with both passive and active balancing systems implemented, which created four different aging paths in the pack. The life model successfully captured the aging trajectories of all four paths. The life model prediction errors on capacity fade and resistance growth were within +/-3% and +/-5% of the experiment measurements.

  16. Shelf-Life Prediction of Chilled Foods

    Science.gov (United States)

    Gudmundsson, Gudmundur; Kristbergsson, Kristberg

    All foods have a finite shelf life. Even foods, which mature with time, will in the end deteriorate, although their life span can exceed 100 years. Definitions of shelf life of food products differ. Some stress the suitability of the product for consump¬tion, others for how long the product can be sold. The Institute of Food Science and Technology emphasizes safety in its definition of shelf life: "The period of time under defined conditions of storage, after manufacture or packing, for which a food product will remain safe and be fit for use" ( http://www.ifst.org ). This definition does not describe what makes a food product "safe" or "fit" for use, but one can say all factors which restrict the shelf life of a food product either affect safety or quality or both.

  17. Entropy and the Predictability of Online Life

    CERN Document Server

    Sinatra, Roberta

    2014-01-01

    Using mobile phone records and information theory measures, our daily lives have been recently shown to follow strict statistical regularities, and our movement patterns are to a large extent predictable. Here, we apply entropy and predictability measures to two data sets of the behavioral actions and the mobility of a large number of players in the virtual universe of a massive multiplayer online game. We find that movements in virtual human lives follow the same high levels of predictability as offline mobility, where future movements can to some extent be predicted well if the temporal correlations of visited places are accounted for. Time series of behavioral actions show similar high levels of predictability, even when temporal correlations are neglected. Entropy conditional on specific behavioral actions reveals that in terms of predictability negative behavior has a wider variety than positive actions. The actions which contain information to best predict an individual's subsequent action are negative,...

  18. Entropy and the Predictability of Online Life

    Directory of Open Access Journals (Sweden)

    Roberta Sinatra

    2014-01-01

    Full Text Available Using mobile phone records and information theory measures, our daily lives have been recently shown to follow strict statistical regularities, and our movement patterns are, to a large extent, predictable. Here, we apply entropy and predictability measures to two datasets of the behavioral actions and the mobility of a large number of players in the virtual universe of a massive multiplayer online game. We find that movements in virtual human lives follow the same high levels of predictability as offline mobility, where future movements can, to some extent, be predicted well if the temporal correlations of visited places are accounted for. Time series of behavioral actions show similar high levels of predictability, even when temporal correlations are neglected. Entropy conditional on specific behavioral actions reveals that in terms of predictability, negative behavior has a wider variety than positive actions. The actions that contain the information to best predict an individual’s subsequent action are negative, such as attacks or enemy markings, while the positive actions of friendship marking, trade and communication contain the least amount of predictive information. These observations show that predicting behavioral actions requires less information than predicting the mobility patterns of humans for which the additional knowledge of past visited locations is crucial and that the type and sign of a social relation has an essential impact on the ability to determine future behavior.

  19. Actual service life prediction of building components

    DEFF Research Database (Denmark)

    Aagaard, Niels-Jørgen; Brandt, Erik; Hansen, Ernst Jan de Place

    2014-01-01

    In recent years, sustainability and life cycle cost in the construction industry have been given great attention in many countries due to the heavy climatic and environmental impact from this sector. In Denmark, a sustainability certification scheme for buildings has been developed including...... such as economics, aesthetics and use of the building. Each of these factors is regarded as a stochastic variable and can be seen as competing causes of bringing service life to an end. A model is proposed for combining such variables resulting in the actual service life of building components. Furthermore...

  20. Predicting Battery Life for Electric UAVs

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a novel battery health management technology for the new generation of electric unmanned aerial vehicles powered by long-life, high-density,...

  1. Life prediction of thermal-mechanical fatigue using strainrange partitioning

    Science.gov (United States)

    Halford, G. R.; Manson, S. S.

    1975-01-01

    This paper describes the applicability of the method of Strainrange Partitioning to the life prediction of thermal-mechanical strain-cycling fatigue. An in-phase test on 316 stainless steel is analyzed as an illustrative example. The observed life is in excellent agreement with the life predicted by the method using the recently proposed Step-Stress Method of experimental partitioning, the Interaction Damage Rule, and the life relationships determined at an isothermal temperature of 705 C. Implications of the present study are discussed relative to the general thermal fatigue problem.

  2. Investigation of Accelerated Life Prediction Techniques

    Science.gov (United States)

    1975-10-01

    1974, AD 784 188. 2. Rabinowicz , E., McEntire, R. H., and Shwalkar, B., A TECHNIQUE FOR ACCELERATED LIFE TESTING, Trans. ASME, August 1970, pp...706-710. 3. Rabinowicz , E., FRICTION AND WEAR OF MATERIALS, New York, John Wiley and Sons, 1966. 4. MacGregor, C. W. (ed), HANDBOOK OF

  3. Life prediction of Ni-base superalloy

    Indian Academy of Sciences (India)

    M Aghaie-Khafri; M Noori

    2011-04-01

    Rene 80 samples were creep–rupture tested in air between 1144 and 1255 K at various stress levels. The mean stress exponent, , and the mean activation energy for creep were calculated from the experimental results. The accelerated creep life of the alloy was evaluated by using iso-stress parametric equations and Monkman–Grant method.

  4. Enhanced Prediction of Gear Tooth Surface Fatigue Life Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sentient will develop an enhanced prediction of gear tooth surface fatigue life with rigorous analysis of the tribological phenomena that contribute to pitting...

  5. A predictive fatigue life model for anodized 7050 aluminium alloy

    OpenAIRE

    Chaussumier, Michel; Mabru, Catherine; Shahzad, Majid; Chieragatti, Rémy; Rezaï-Aria, Farhad

    2013-01-01

    International audience; The objective of this study is to predict fatigue life of anodized 7050 aluminum alloy specimens. In the case of anodized 7050-T7451 alloy, fractographic observations of fatigue tested specimens showed that pickling pits were the predominant sites for crack nucleation and subsequent failure. It has been shown that fatigue failure was favored by the presence of multiple cracks. From these experimental results, a fatigue life predictive model has been developed including...

  6. Service life prediction of exterior plastics vision for the future

    CERN Document Server

    Martin, Jon; Chapin, J

    2015-01-01

    This book defines the current state-of-the-art for predicting the lifetime of plastics exposed to weather and outlines future research needed to advance this important field of study. Coverage includes progress in developing new science and test methods to determine how materials respond to weather exposure. This book is ideal for researchers and professionals working in the field of service life prediction. This book also: Examines numerous consensus standards that affect commercial products allowing readers to see the future of standards related to service life prediction Provides the scientific foundation for the latest commercially viable instruments Presents groundbreaking research, including the blueprint of a new test method that will significantly shorten the service life prediction process time Covers two of the latest verified predictive models, which demonstrate realized-potential to transform the field

  7. Predicting life satisfaction of the Angolan elderly: a structural model.

    Science.gov (United States)

    Gutiérrez, M; Tomás, J M; Galiana, L; Sancho, P; Cebrià, M A

    2013-01-01

    Satisfaction with life is of particular interest in the study of old age well-being because it has arisen as an important component of old age. A considerable amount of research has been done to explain life satisfaction in the elderly, and there is growing empirical evidence on best predictors of life satisfaction. This research evaluates the predictive power of some aging process variables, on Angolan elderly people's life satisfaction, while including perceived health into the model. Data for this research come from a cross-sectional survey of elderly people living in the capital of Angola, Luanda. A total of 1003 Angolan elderly were surveyed on socio-demographic information, perceived health, active engagement, generativity, and life satisfaction. A Multiple Indicators Multiple Causes model was built to test variables' predictive power on life satisfaction. The estimated theoretical model fitted the data well. The main predictors were those related to active engagement with others. Perceived health also had a significant and positive effect on life satisfaction. Several processes together may predict life satisfaction in the elderly population of Angola, and the variance accounted for it is large enough to be considered relevant. The key factor associated to life satisfaction seems to be active engagement with others.

  8. Enhancing the Predicting Accuracy of the Water Stage Using a Physical-Based Model and an Artificial Neural Network-Genetic Algorithm in a River System

    National Research Council Canada - National Science Library

    Wen-Cheng Liu; Chuan-En Chung

    2014-01-01

    ...) and genetic algorithm neural network (GANN) techniques, to improve predictions from a one-dimensional flood routing hydrodynamic model regarding the water stages during typhoon events in the Danshuei River system in northern Taiwan...

  9. PRODUCT DATA PREDICTION WITH UNCERTAINTY IN PRODUCT LIFE CYCLE DESIGN

    Institute of Scientific and Technical Information of China (English)

    Yu Suiran; Wang Chengtao; Kimura Fumihiko

    2003-01-01

    Various kinds of data are used in new product design and more accurate data make the design results more reliable. Even though part of product data can be available directly from the existing similar products, there still leaves a great deal of data unavailable. This makes data prediction a valuable work. A method that can predict data of product under development based on the existing similar products is proposed. Fuzzy theory is used to deal with the uncertainties in data prediction process. The proposed method can be used in life cycle design, life cycle assessment (LCA) etc. Case study on current refrigerator is used as a demonstration example.

  10. Life history theory predicts fish assemblage response to hydrologic regimes.

    Science.gov (United States)

    Mims, Meryl C; Olden, Julian D

    2012-01-01

    The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P history strategies, with 82% of all significant relationships observed supporting predictions from life history theory. Specifically, we found that (1) opportunistic strategists were positively related to measures of flow variability and negatively related to predictability and seasonality, (2) periodic strategists were positively related to high flow seasonality and negatively related to variability, and (3) the equilibrium strategists were negatively related to flow variability and positively related to predictability. Our study provides important empirical evidence illustrating the value of using life history theory to understand both the patterns and processes by which fish assemblage structure is shaped by adaptation to natural regimes of variability, predictability, and seasonality of critical flow events over broad biogeographic scales.

  11. A comparison of fatigue life prediction methodologies for rotorcraft

    Science.gov (United States)

    Everett, R. A., Jr.

    1990-01-01

    Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra.

  12. Predicting young children's quality of life.

    Science.gov (United States)

    Jirojanakul, Pragai; Skevington, Suzanne M; Hudson, John

    2003-10-01

    This paper represents an investigation into the determinants of young children's quality of life (QOL) in Thailand. The empirical work is based upon a sample of 498 children (aged 5-8); 220 were urban children and 278 children of construction workers in Bangkok. Their QOL was assessed using a new self-report QOL measure for children. Multiple regression analyses indicated that the father's income and education, type of school, mode of transportation to school, and the amount of time that the child spent on extra study courses were significant explanatory variables. It was found that these factors had different influences on the QOL of urban children and those of construction workers. Extra sport-related activities and extra work (other than housework) improved the QOL of urban children, while the QOL of construction workers' children was directly linked to father's education and income. This result is consistent with income having a diminishing marginal effect on the QOL of children. There is also evidence that amongst construction workers' children, boys have a lower QOL than girls. The different causal explanations for the QOL of urban and construction workers' children suggests that it is context specific, and what impacts one group of children's QOL within a particular context may not impact another group in a different situation. This has important policy implications. Throughout the study we could find no significant impact of health on QOL-neither chronic, acute nor severe illness has any significant impact on QOL. This is consistent with the hypothesis that QOL is influenced by expectations (Social Science and Medicine 41 (10) (1995) 1403). Findings of the effects of social and environmental factors on children's QOL are new in this field and should be further investigated.

  13. Benchmark notch test for life prediction

    Science.gov (United States)

    Domas, P. A.; Yau, J.; Sharpe, W. N.; Ward, M.

    1982-01-01

    Aircraft gas turbine engine components are subjected to severe stress, temperature, and environmental conditions. Economic and reliabilty demands have prompted inordinate effort in development of analytic methods to predict stresses and strains in aircraft engines. There remains, however, the need to check or verify these analytical methodologies against actual experimental data measurements. The laser interferometric strain displacement gage was recognized as having the potential to accomplish this task and was employed in this program. The actual strains incurred at the root of a discontinuity in cyclically loaded test samples subjected to inelastic deformation at high temperature where creep deformation readily occur were measured. The steady-state, cyclic stress-strain response at the root of the discontinuity in the tested samples was analyzed for comparison with the measured results. A comprehensive set of local notch root strain measurements for a variety of load patterns in an Inconel 718 notch specimen at 649 C (1200 F) was obtained and documented using the laser interferometric strain displacement gage.

  14. Neural Network Modeling to Predict Shelf Life of Greenhouse Lettuce

    Directory of Open Access Journals (Sweden)

    Wei-Chin Lin

    2009-04-01

    Full Text Available Greenhouse-grown butter lettuce (Lactuca sativa L. can potentially be stored for 21 days at constant 0°C. When storage temperature was increased to 5°C or 10°C, shelf life was shortened to 14 or 10 days, respectively, in our previous observations. Also, commercial shelf life of 7 to 10 days is common, due to postharvest temperature fluctuations. The objective of this study was to establish neural network (NN models to predict the remaining shelf life (RSL under fluctuating postharvest temperatures. A box of 12 - 24 lettuce heads constituted a sample unit. The end of the shelf life of each head was determined when it showed initial signs of decay or yellowing. Air temperatures inside a shipping box were recorded. Daily average temperatures in storage and averaged shelf life of each box were used as inputs, and the RSL was modeled as an output. An R2 of 0.57 could be observed when a simple NN structure was employed. Since the "future" (or remaining storage temperatures were unavailable at the time of making a prediction, a second NN model was introduced to accommodate a range of future temperatures and associated shelf lives. Using such 2-stage NN models, an R2 of 0.61 could be achieved for predicting RSL. This study indicated that NN modeling has potential for cold chain quality control and shelf life prediction.

  15. Enhancing the Predicting Accuracy of the Water Stage Using a Physical-Based Model and an Artificial Neural Network-Genetic Algorithm in a River System

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Liu

    2014-06-01

    Full Text Available Accurate simulations of river stages during typhoon events are critically important for flood control and are necessary for disaster prevention and water resources management in Taiwan. This study applies two artificial neural network (ANN models, including the back propagation neural network (BPNN and genetic algorithm neural network (GANN techniques, to improve predictions from a one-dimensional flood routing hydrodynamic model regarding the water stages during typhoon events in the Danshuei River system in northern Taiwan. The hydrodynamic model is driven by freshwater discharges at the upstream boundary conditions and by the water levels at the downstream boundary condition. The model provides a sound physical basis for simulating water stages along the river. The simulated results of the hydrodynamic model show that the model cannot reproduce the water stages at different stations during typhoon events for the model calibration and verification phases. The BPNN and GANN models can improve the simulated water stages compared with the performance of the hydrodynamic model. The GANN model satisfactorily predicts water stages during the training and verification phases and exhibits the lowest values of mean absolute error, root-mean-square error and peak error compared with the simulated results at different stations using the hydrodynamic model and the BPNN model. Comparison of the simulated results shows that the GANN model can be successfully applied to predict the water stages of the Danshuei River system during typhoon events.

  16. Fracture Mechanics Prediction of Fatigue Life of Aluminum Highway Bridges

    DEFF Research Database (Denmark)

    Rom, Søren; Agerskov, Henning

    2015-01-01

    Fracture mechanics prediction of the fatigue life of aluminum highway bridges under random loading is studied. The fatigue life of welded joints has been determined from fracture mechanics analyses and the results obtained have been compared with results from experimental investigations. The fati......Fracture mechanics prediction of the fatigue life of aluminum highway bridges under random loading is studied. The fatigue life of welded joints has been determined from fracture mechanics analyses and the results obtained have been compared with results from experimental investigations...... against fatigue in aluminum bridges, may give results which are unconservative. Furthermore, it was in both investigations found that the validity of the results obtained from Miner's rule will depend on the distribution of the load history in tension and compression....

  17. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    Directory of Open Access Journals (Sweden)

    Ma Xiaobing

    2015-01-01

    Full Text Available An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life test due to the time limitation. Therefore, most of the data presented to be high censored in high stress level and zero-failure data in low stress level. When using the traditional method for rupture life prediction, the results showed to be of lower confidence. In this study, the consistency of failure mechanism for carbon fiber and cylinder was analyzed firstly. According to the analysis result, the statistical test information of carbon fiber could be utilized for the accelerated model constitution. Then, rupture life prediction method for cylinder was proposed based on the accelerated life test data and carbon fiber test data. In this way, the life prediction accuracy of cylinder could be improved obviously, and the results showed that the accuracy of this method increased by 35%.

  18. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    Directory of Open Access Journals (Sweden)

    Eric J. Tuegel

    2011-01-01

    Full Text Available Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the life of aircraft structure and assuring its structural integrity is presented. The technical challenges to developing and deploying a Digital Twin are discussed in detail.

  19. FATIGUE LIFE PREDICTION THEORY OF COMPOSITE LAMINATES AND EXPERIMENTAL VERIFICATION

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    According to traditional phenomenological fatigue methodology and modern continuum damage mechanics theory, dual fatigue cumulative damage rules to predict fatigue damage formation and propagation lives of the notched composite laminates are presented.A 3-dimensional damage constitutive equation of anisotropic composites is also established.Damage strain energy release rate is interpreted as a driving force of the fatigue delamination damage propagation.A new damage evolution equation and a damage propagation (a-(m-N( surface (stress amplitude-mean stress-life surface) are derived.Hence, using the method above, the fatigue life of composite components can be predicted.Finally, theoretically predicted results are compared with experimental data.It is found that the deviation of theoretic prediction from experimental results is about 22%.

  20. Service life prediction and fibre reinforced cementitious composites

    DEFF Research Database (Denmark)

    Stoklund Larsen, E.

    The present Ph.D.thesis addresses the service life concept on the fibre reinforced cementitious composites. The advantages and problems of adding fibre to a cementitious matrix and the influence on service life are described. In SBI Report 221, Service life prediction and cementitious somposites......, the factors affecting the pure cementitious composite are described. Different sizes and types of fibre reinforced crmentitious composites have been chosen to illustrate different ageing and deterioration mechanisms. Some ageing mechanisms can be accelerated and others cannot which is demonstrated in a test...

  1. Reengineering Aircraft Structural Life Prediction Using a Digital Twin

    OpenAIRE

    Eric J. Tuegel; Anthony R. Ingraffea; Eason, Thomas G.; S. Michael Spottswood

    2011-01-01

    Reengineering of the aircraft structural life prediction process to fully exploit advances in very high performance digital computing is proposed. The proposed process utilizes an ultrahigh fidelity model of individual aircraft by tail number, a Digital Twin, to integrate computation of structural deflections and temperatures in response to flight conditions, with resulting local damage and material state evolution. A conceptual model of how the Digital Twin can be used for predicting the lif...

  2. Satellite Collision Modeling with Physics-Based Hydrocodes: Debris Generation Predictions of the Iridium-Cosmos Collision Event and Other Impact Events

    Energy Technology Data Exchange (ETDEWEB)

    Springer, H K; Miller, W O; Levatin, J L; Pertica, A J; Olivier, S S

    2010-09-06

    Satellite collision debris poses risks to existing space assets and future space missions. Predictive models of debris generated from these hypervelocity collisions are critical for developing accurate space situational awareness tools and effective mitigation strategies. Hypervelocity collisions involve complex phenomenon that spans several time- and length-scales. We have developed a satellite collision debris modeling approach consisting of a Lagrangian hydrocode enriched with smooth particle hydrodynamics (SPH), advanced material failure models, detailed satellite mesh models, and massively parallel computers. These computational studies enable us to investigate the influence of satellite center-of-mass (CM) overlap and orientation, relative velocity, and material composition on the size, velocity, and material type distributions of collision debris. We have applied our debris modeling capability to the recent Iridium 33-Cosmos 2251 collision event. While the relative velocity was well understood in this event, the degree of satellite CM overlap and orientation was ill-defined. In our simulations, we varied the collision CM overlap and orientation of the satellites from nearly maximum overlap to partial overlap on the outermost extents of the satellites (i.e, solar panels and gravity boom). As expected, we found that with increased satellite overlap, the overall debris cloud mass and momentum (transfer) increases, the average debris size decreases, and the debris velocity increases. The largest predicted debris can also provide insight into which satellite components were further removed from the impact location. A significant fraction of the momentum transfer is imparted to the smallest debris (< 1-5mm, dependent on mesh resolution), especially in large CM overlap simulations. While the inclusion of the smallest debris is critical to enforcing mass and momentum conservation in hydrocode simulations, there seems to be relatively little interest in their

  3. Shelf Life Prediction for Canned Gudeg using Accelerated Shelf Life Testing (ASLT) Based on Arrhenius Method

    Science.gov (United States)

    Nurhayati, R.; Rahayu NH, E.; Susanto, A.; Khasanah, Y.

    2017-04-01

    Gudeg is traditional food from Yogyakarta. It is consist of jackfruit, chicken, egg and coconut milk. Gudeg generally have a short shelf life. Canning or commercial sterilization is one way to extend the shelf life of gudeg. This aims of this research is to predict the shelf life of Andrawinaloka canned gudeg with Accelerated Shelf Life Test methods, Arrhenius model. Canned gudeg stored at three different temperature, there are 37, 50 and 60°C for two months. Measuring the number of Thio Barbituric Acid (TBA), as a critical aspect, were tested every 7 days. Arrhenius model approach is done with the equation order 0 and order 1. The analysis showed that the equation of order 0 can be used as an approach to estimating the shelf life of canned gudeg. The storage of Andrawinaloka canned gudeg at 30°C is predicted untill 21 months and 24 months for 25°C.

  4. A multi-time scale approach to remaining useful life prediction in rolling bearing

    Science.gov (United States)

    Qian, Yuning; Yan, Ruqiang; Gao, Robert X.

    2017-01-01

    This paper presents a novel multi-time scale approach to bearing defect tracking and remaining useful life (RUL) prediction, which integrates enhanced phase space warping (PSW) with a modified Paris crack growth model. As a data-driven method, PSW describes the dynamical behavior of the bearing being tested on a fast-time scale, whereas the Paris crack growth model, as a physics-based model, characterizes the bearing's defect propagation on a slow-time scale. Theoretically, PSW constructs a tracking metric by evaluating the phase space trajectory warping of the bearing vibration data, and establishes a correlation between measurement on a fast-time scale and defect growth variables on a slow-time scale. Furthermore, PSW is enhanced by a multi-dimensional auto-regression (AR) model for improved accuracy in defect tracking. Also, the Paris crack growth model is modified by a time-piecewise algorithm for real-time RUL prediction. Case studies performed on two run-to-failure experiments indicate that the developed technique is effective in tracking the evolution of bearing defects and accurately predict the bearing RUL, thus contributing to the literature of bearing prognosis .

  5. Innovative predictive maintenance concepts to improve life cycle management

    NARCIS (Netherlands)

    Tinga, T.

    2014-01-01

    For naval systems with typically long service lives, high sustainment costs and strict availability requirements, an effective and efficient life cycle management process is very important. In this paper four approaches are discussed to improve that process: physics of failure based predictive maint

  6. Survey on damage mechanics models for fatigue life prediction

    NARCIS (Netherlands)

    Silitonga, S.; Maljaars, J.; Soetens, F.; Snijder, H.H.

    2013-01-01

    Engineering methods to predict the fatigue life of structures have been available since the beginning of the 20th century. However, a practical problem arises from complex loading conditions and a significant concern is the accuracy of the methods under variable amplitude loading. This paper provide

  7. Remaining useful tool life predictions in turning using Bayesian inference

    Directory of Open Access Journals (Sweden)

    Jaydeep M. Karandikar

    2013-01-01

    Full Text Available Tool wear is an important factor in determining machining productivity. In this paper, tool wear is characterized by remaining useful tool life in a turning operation and is predicted using spindle power and a random sample path method of Bayesian inference. Turning tests are performed at different speeds and feed rates using a carbide tool and MS309 steel work material. The spindle power and the tool flank wear are monitored during cutting; the root mean square of the time domain power is found to be sensitive to tool wear. Sample root mean square power growth curves are generated and the probability of each curve being the true growth curve is updated using Bayes’ rule. The updated probabilities are used to determine the remaining useful tool life. Results show good agreement between the predicted tool life and the empirically-determined true remaining life. The proposed method takes into account the uncertainty in tool life and the growth of the root mean square power at the end of tool life and is, therefore, robust and reliable.

  8. Towards a unified fatigue life prediction method for marine structures

    CERN Document Server

    Cui, Weicheng; Wang, Fang

    2014-01-01

    In order to apply the damage tolerance design philosophy to design marine structures, accurate prediction of fatigue crack growth under service conditions is required. Now, more and more people have realized that only a fatigue life prediction method based on fatigue crack propagation (FCP) theory has the potential to explain various fatigue phenomena observed. In this book, the issues leading towards the development of a unified fatigue life prediction (UFLP) method based on FCP theory are addressed. Based on the philosophy of the UFLP method, the current inconsistency between fatigue design and inspection of marine structures could be resolved. This book presents the state-of-the-art and recent advances, including those by the authors, in fatigue studies. It is designed to lead the future directions and to provide a useful tool in many practical applications. It is intended to address to engineers, naval architects, research staff, professionals and graduates engaged in fatigue prevention design and survey ...

  9. The value of oxygen-isotope data and multiple discharge records in calibrating a fully-distributed, physically-based rainfall-runoff model (CRUM3) to improve predictive capability

    Science.gov (United States)

    Neill, Aaron; Reaney, Sim

    2015-04-01

    Fully-distributed, physically-based rainfall-runoff models attempt to capture some of the complexity of the runoff processes that operate within a catchment, and have been used to address a variety of issues including water quality and the effect of climate change on flood frequency. Two key issues are prevalent, however, which call into question the predictive capability of such models. The first is the issue of parameter equifinality which can be responsible for large amounts of uncertainty. The second is whether such models make the right predictions for the right reasons - are the processes operating within a catchment correctly represented, or do the predictive abilities of these models result only from the calibration process? The use of additional data sources, such as environmental tracers, has been shown to help address both of these issues, by allowing for multi-criteria model calibration to be undertaken, and by permitting a greater understanding of the processes operating in a catchment and hence a more thorough evaluation of how well catchment processes are represented in a model. Using discharge and oxygen-18 data sets, the ability of the fully-distributed, physically-based CRUM3 model to represent the runoff processes in three sub-catchments in Cumbria, NW England has been evaluated. These catchments (Morland, Dacre and Pow) are part of the of the River Eden demonstration test catchment project. The oxygen-18 data set was firstly used to derive transit-time distributions and mean residence times of water for each of the catchments to gain an integrated overview of the types of processes that were operating. A generalised likelihood uncertainty estimation procedure was then used to calibrate the CRUM3 model for each catchment based on a single discharge data set from each catchment. Transit-time distributions and mean residence times of water obtained from the model using the top 100 behavioural parameter sets for each catchment were then compared to

  10. Physics-Based Pneumatic Hammer Instability Model Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop a physics-based pneumatic hammer instability model that accurately predicts the stability of hydrostatic bearings...

  11. DNA Sequencing and Predictions of the Cosmic Theory of Life

    Science.gov (United States)

    Wickramasinghe, N. Chandra

    The theory of cometary panspermia, developed by the late Sir Fred Hoyle and the present author argues that life originated cosmically as a unique event in one of a great multitude of comets or planetary bodies in the Universe. Life on Earth did not originate here but was introduced by impacting comets, and its further evolution was driven by the subsequent acquisition of cosmically derived genes. Explicit predictions of this theory published in 1979-1981, stating how the acquisition of new genes drives evolution, are compared with recent developments in relation to horizontal gene transfer, and the role of retroviruses in evolution. Precisely-stated predictions of the theory of cometary panspermia are shown to have been verified.

  12. Life prediction of advanced materials for gas turbine application

    Energy Technology Data Exchange (ETDEWEB)

    Zamrik, S.Y.; Ray, A.; Koss, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-10-01

    Most of the studies on the low cycle fatigue life prediction have been reported under isothermal conditions where the deformation of the material is strain dependent. In the development of gas turbines, components such as blades and vanes are exposed to temperature variations in addition to strain cycling. As a result, the deformation process becomes temperature and strain dependent. Therefore, the life of the component becomes sensitive to temperature-strain cycling which produces a process known as {open_quotes}thermomechanical fatigue, or TMF{close_quotes}. The TMF fatigue failure phenomenon has been modeled using conventional fatigue life prediction methods, which are not sufficiently accurate to quantitatively establish an allowable design procedure. To add to the complexity of TMF life prediction, blade and vane substrates are normally coated with aluminide, overlay or thermal barrier type coatings (TBC) where the durability of the component is dominated by the coating/substrate constitutive response and by the fatigue behavior of the coating. A number of issues arise from TMF depending on the type of temperature/strain phase cycle: (1) time-dependent inelastic behavior can significantly affect the stress response. For example, creep relaxation during a tensile or compressive loading at elevated temperatures leads to a progressive increase in the mean stress level under cyclic loading. (2) the mismatch in elastic and thermal expansion properties between the coating and the substrate can lead to significant deviations in the coating stress levels due to changes in the elastic modulii. (3) the {open_quotes}dry{close_quotes} corrosion resistance coatings applied to the substrate may act as primary crack initiation sites. Crack initiation in the coating is a function of the coating composition, its mechanical properties, creep relaxation behavior, thermal strain range and the strain/temperature phase relationship.

  13. Patterns, entropy, and predictability of human mobility and life.

    Directory of Open Access Journals (Sweden)

    Shao-Meng Qin

    Full Text Available Cellular phones are now offering an ubiquitous means for scientists to observe life: how people act, move and respond to external influences. They can be utilized as measurement devices of individual persons and for groups of people of the social context and the related interactions. The picture of human life that emerges shows complexity, which is manifested in such data in properties of the spatiotemporal tracks of individuals. We extract from smartphone-based data for a set of persons important locations such as "home", "work" and so forth over fixed length time-slots covering the days in the data-set (see also [1], [2]. This set of typical places is heavy-tailed, a power-law distribution with an exponent close to -1.7. To analyze the regularities and stochastic features present, the days are classified for each person into regular, personal patterns. To this are superimposed fluctuations for each day. This randomness is measured by "life" entropy, computed both before and after finding the clustering so as to subtract the contribution of a number of patterns. The main issue that we then address is how predictable individuals are in their mobility. The patterns and entropy are reflected in the predictability of the mobility of the life both individually and on average. We explore the simple approaches to guess the location from the typical behavior, and of exploiting the transition probabilities with time from location or activity A to B. The patterns allow an enhanced predictability, at least up to a few hours into the future from the current location. Such fixed habits are most clearly visible in the working-day length.

  14. Recent Methodologies for Creep Deformation Analysis and Its Life Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo-Gon; Park, Jae-Young; Iung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    To design the high-temperature creeping materials, various creep data are needed for codification, as follows: i) stress vs. creep rupture time for base metals and weldments (average and minimum), ii) stress vs. time to 1% total strain (average), iii) stress vs. time to onset of tertiary creep (minimum), and iv) constitutive eqns. for conducting time- and temperature- dependent stress-strain (average), and v) isochronous stress-strain curves (average). Also, elevated temperature components such as those used in modern power generation plant are designed using allowable stress under creep conditions. The allowable stress is usually estimated on the basis of up to 10{sup 5} h creep rupture strength at the operating temperature. The master curve of the “sinh” function was found to have a wider acceptance with good flexibility in the low stress ranges beyond the experimental data. The proposed multi-C method in the LM parameter revealed better life prediction than a single-C method. These improved methodologies can be utilized to accurately predict the long-term creep life or strength of Gen-IV nuclear materials which are designed for life span of 60 years.

  15. Half-life predictions for decay modes of superheavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, S.B.; Tavares, O.A.P. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil); Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencias e Tecnologia Nucleares (InSTEC), La Habana (Cuba); Barbosa, T.N.; Garcia, F.; Dimarco, A. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas

    2004-09-01

    We applied the Effective Liquid Drop Model (ELDM) to predict the alpha-decay, cluster emission and cold fission half-life-values of nuclei in the region of Superheavy Elements (SHE). The present calculations have been made in the region of the ZN-plane defined by 155 <=N <=220 and 110<=Z<=135. Shell effects are included via the Q-value of the corresponding decay case. We report the results of a systematic calculation of the half-life for the three nuclear decay modes in a region of the ZN-plane where superheavy elements are expected to be found. Results have shown that, among the decay modes investigated here, the alpha decay is the dominant one. i.e, the decay mode of smallest half-lives. Half-life predictions for alpha decay, cluster emission and cold fission for the isotopic family of the most recent SHE detected of Z=115 and for the isotopic family of the already consolidated SHE of Z=111 are presented. (author)

  16. Predicting later life health status and mortality using state-level socioeconomic characteristics in early life.

    Science.gov (United States)

    Hamad, Rita; Rehkopf, David H; Kuan, Kai Y; Cullen, Mark R

    2016-12-01

    Studies extending across multiple life stages promote an understanding of factors influencing health across the life span. Existing work has largely focused on individual-level rather than area-level early life determinants of health. In this study, we linked multiple data sets to examine whether early life state-level characteristics were predictive of health and mortality decades later. The sample included 143,755 U.S. employees, for whom work life claims and administrative data were linked with early life state-of-residence and mortality. We first created a "state health risk score" (SHRS) and "state mortality risk score" (SMRS) by modeling state-level contextual characteristics with health status and mortality in a randomly selected 30% of the sample (the "training set"). We then examined the association of these scores with objective health status and mortality in later life in the remaining 70% of the sample (the "test set") using multivariate linear and Cox regressions, respectively. The association between the SHRS and adult health status was β=0.14 (95%CI: 0.084, 0.20), while the hazard ratio for the SMRS was 0.96 (95%CI: 0.93, 1.00). The association between the SHRS and health was not statistically significant in older age groups at a p-level of 0.05, and there was a statistically significantly different association for health status among movers compared to stayers. This study uses a life course perspective and supports the idea of "sensitive periods" in early life that have enduring impacts on health. It adds to the literature examining populations in the U.S. where large linked data sets are infrequently available.

  17. Predicting remaining life in upper sugar-mill shafts

    Directory of Open Access Journals (Sweden)

    Sara Rodríguez Pulecio

    2010-04-01

    Full Text Available A fracture mechanics-based method is presented for determining critical crack size and residual life of upper sugar-mill shafts having semi-elliptical and circumferential cracks. Due to the multiaxial stress field, an equivalent strain energy release rate stress intensity solution is used in Paris’ law to predict crack growth. Ultrasonic inspection intervals for the shaft were established. The crack zone evaluated was located in the shoulder of the bearing nearest to the square box coupling where about 25% of service failures in these types of shaft are observed.

  18. Genetic Risk Score Predicts Late-Life Cognitive Impairment

    Directory of Open Access Journals (Sweden)

    Mariegold E. Wollam

    2015-01-01

    Full Text Available Introduction. A family history of Alzheimer’s disease is a significant risk factor for its onset, but the genetic risk associated with possessing multiple risk alleles is still poorly understood. Methods. In a sample of 95 older adults (Mean age = 75.1, 64.2% female, we constructed a genetic risk score based on the accumulation of risk alleles in BDNF, COMT, and APOE. A neuropsychological evaluation and consensus determined cognitive status (44 nonimpaired, 51 impaired. Logistic regression was performed to determine whether the genetic risk score predicted cognitive impairment above and beyond that associated with each gene. Results. An increased genetic risk score was associated with a nearly 4-fold increased risk of cognitive impairment (OR = 3.824, P = .013 when including the individual gene polymorphisms as covariates in the model. Discussion. A risk score combining multiple genetic influences may be more useful in predicting late-life cognitive impairment than individual polymorphisms.

  19. Cumulative early life adversity predicts longevity in wild baboons.

    Science.gov (United States)

    Tung, Jenny; Archie, Elizabeth A; Altmann, Jeanne; Alberts, Susan C

    2016-04-19

    In humans and other animals, harsh circumstances in early life predict morbidity and mortality in adulthood. Multiple adverse conditions are thought to be especially toxic, but this hypothesis has rarely been tested in a prospective, longitudinal framework, especially in long-lived mammals. Here we use prospective data on 196 wild female baboons to show that cumulative early adversity predicts natural adult lifespan. Females who experience ≥3 sources of early adversity die a median of 10 years earlier than females who experience ≤1 adverse circumstances (median lifespan is 18.5 years). Females who experience the most adversity are also socially isolated in adulthood, suggesting that social processes partially explain the link between early adversity and adult survival. Our results provide powerful evidence for the developmental origins of health and disease and indicate that close ties between early adversity and survival arise even in the absence of health habit and health care-related explanations.

  20. CARES/LIFE Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program

    Science.gov (United States)

    Nemeth, Noel N.; Powers, Lynn M.; Janosik, Lesley A.; Gyekenyesi, John P.

    2003-01-01

    This manual describes the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction (CARES/LIFE) computer program. The program calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. CARES/LIFE is an extension of the CARES (Ceramic Analysis and Reliability Evaluation of Structures) computer program. The program uses results from MSC/NASTRAN, ABAQUS, and ANSYS finite element analysis programs to evaluate component reliability due to inherent surface and/or volume type flaws. CARES/LIFE accounts for the phenomenon of subcritical crack growth (SCG) by utilizing the power law, Paris law, or Walker law. The two-parameter Weibull cumulative distribution function is used to characterize the variation in component strength. The effects of multiaxial stresses are modeled by using either the principle of independent action (PIA), the Weibull normal stress averaging method (NSA), or the Batdorf theory. Inert strength and fatigue parameters are estimated from rupture strength data of naturally flawed specimens loaded in static, dynamic, or cyclic fatigue. The probabilistic time-dependent theories used in CARES/LIFE, along with the input and output for CARES/LIFE, are described. Example problems to demonstrate various features of the program are also included.

  1. Development of a Generic Creep-Fatigue Life Prediction Model

    Science.gov (United States)

    Goswami, Tarun

    2002-01-01

    The objective of this research proposal is to further compile creep-fatigue data of steel alloys and superalloys used in military aircraft engines and/or rocket engines and to develop a statistical multivariate equation. The newly derived model will be a probabilistic fit to all the data compiled from various sources. Attempts will be made to procure the creep-fatigue data from NASA Glenn Research Center and other sources to further develop life prediction models for specific alloy groups. In a previous effort [1-3], a bank of creep-fatigue data has been compiled and tabulated under a range of known test parameters. These test parameters are called independent variables, namely; total strain range, strain rate, hold time, and temperature. The present research attempts to use these variables to develop a multivariate equation, which will be a probabilistic equation fitting a large database. The data predicted by the new model will be analyzed using the normal distribution fits, the closer the predicted lives are with the experimental lives (normal line 1 to 1 fit) the better the prediction. This will be evaluated in terms of a coefficient of correlation, R 2 as well. A multivariate equation developed earlier [3] has the following form, where S, R, T, and H have specific meaning discussed later.

  2. Personality Predicts Health Declines Through Stressful Life Events During Late Mid-Life.

    Science.gov (United States)

    Iacovino, Juliette M; Bogdan, Ryan; Oltmanns, Thomas F

    2016-08-01

    Personality predicts the occurrence of dependent stressful life events (SLE; i.e., events reliant, at least in part, on an individual's behavior). This process, termed stress generation, contributes to psychiatric outcomes, but its role in physical health is unknown. Data were included from 998 participants (aged 55-64) in the St. Louis Personality and Aging Network (SPAN) study. Assessments occurred every 6 months for 18 months. Neuroticism, impulsivity, and agreeableness were measured with the Revised NEO Personality Inventory. Dependent (e.g., divorce) and independent (e.g., family death) SLE occurring within 6 months following baseline were assessed with the List of Threatening Experiences and confirmed by interviews. Health problems occurring within a year after SLE were the outcome. Analyses examined whether neuroticism, impulsivity, and agreeableness indirectly predict the onset of new health problems through exposure to dependent SLE. Each personality trait was associated with dependent, but not independent, SLE. Only dependent SLE predicted new health problems. Each personality trait indirectly predicted the onset of new health problems through dependent SLE. Findings suggest that personality-driven stress generation influences physical health during late mid-life. Addressing personality in interventions may reduce the occurrence of SLE, in turn decreasing health risks.

  3. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    Science.gov (United States)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  4. Evaluating performances of simplified physically based models for landslide susceptibility

    Directory of Open Access Journals (Sweden)

    G. Formetta

    2015-12-01

    Full Text Available Rainfall induced shallow landslides cause loss of life and significant damages involving private and public properties, transportation system, etc. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. Reliable models' applications involve: automatic parameters calibration, objective quantification of the quality of susceptibility maps, model sensitivity analysis. This paper presents a methodology to systemically and objectively calibrate, verify and compare different models and different models performances indicators in order to individuate and eventually select the models whose behaviors are more reliable for a certain case study. The procedure was implemented in package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3 and a component for models verifications. It computes eight goodness of fit indices by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, the optimization of the index distance to perfect classification in the receiver operating characteristic plane (D2PC coupled with model M3 is the best modeling solution for our test case.

  5. Evaluating performances of simplified physically based models for landslide susceptibility

    Science.gov (United States)

    Formetta, G.; Capparelli, G.; Versace, P.

    2015-12-01

    Rainfall induced shallow landslides cause loss of life and significant damages involving private and public properties, transportation system, etc. Prediction of shallow landslides susceptible locations is a complex task that involves many disciplines: hydrology, geotechnical science, geomorphology, and statistics. Usually to accomplish this task two main approaches are used: statistical or physically based model. Reliable models' applications involve: automatic parameters calibration, objective quantification of the quality of susceptibility maps, model sensitivity analysis. This paper presents a methodology to systemically and objectively calibrate, verify and compare different models and different models performances indicators in order to individuate and eventually select the models whose behaviors are more reliable for a certain case study. The procedure was implemented in package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslides susceptibility analysis (M1, M2, and M3) and a component for models verifications. It computes eight goodness of fit indices by comparing pixel-by-pixel model results and measurements data. Moreover, the package integration in NewAge-JGrass allows the use of other components such as geographic information system tools to manage inputs-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia municipality. The analysis provided that among all the optimized indices and all the three models, the optimization of the index distance to perfect classification in the receiver operating characteristic plane (D2PC) coupled with model M3 is the best modeling solution for our test case.

  6. Physics-based prognostic modelling of filter clogging phenomena

    Science.gov (United States)

    Eker, Omer F.; Camci, Fatih; Jennions, Ian K.

    2016-06-01

    In industry, contaminant filtration is a common process to achieve a desired level of purification, since contaminants in liquids such as fuel may lead to performance drop and rapid wear propagation. Generally, clogging of filter phenomena is the primary failure mode leading to the replacement or cleansing of filter. Cascading failures and weak performance of the system are the unfortunate outcomes due to a clogged filter. Even though filtration and clogging phenomena and their effects of several observable parameters have been studied for quite some time in the literature, progression of clogging and its use for prognostics purposes have not been addressed yet. In this work, a physics based clogging progression model is presented. The proposed model that bases on a well-known pressure drop equation is able to model three phases of the clogging phenomena, last of which has not been modelled in the literature yet. In addition, the presented model is integrated with particle filters to predict the future clogging levels and to estimate the remaining useful life of fuel filters. The presented model has been implemented on the data collected from an experimental rig in the lab environment. In the rig, pressure drop across the filter, flow rate, and filter mesh images are recorded throughout the accelerated degradation experiments. The presented physics based model has been applied to the data obtained from the rig. The remaining useful lives of the filters used in the experimental rig have been reported in the paper. The results show that the presented methodology provides significantly accurate and precise prognostic results.

  7. Ways that Social Change Predicts Personal Quality of Life

    Science.gov (United States)

    Cheung, Chau-Kiu; Leung, Kwok

    2010-01-01

    A notable way that social change affects personal quality of life would rely on the person's experience with social change. This experience may influence societal quality of life and quality of work life, which may in turn affect personal quality of life. Additionally, the experience of social change is possibly less detrimental to personal…

  8. Multi-Axial Damage Index and Accumulation Model for Predicting Fatigue Life of CMC Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The fatigue life of CMCs must be well characterized for the safe and reliable use of these materials as integrated TPS components. Existing fatigue life prediction...

  9. Deconstructing environmental predictability: seasonality, environmental colour and the biogeography of marine life histories.

    Science.gov (United States)

    Marshall, Dustin J; Burgess, Scott C

    2015-02-01

    Environmental predictability is predicted to shape the evolution of life histories. Two key types of environmental predictability, seasonality and environmental colour, may influence life-history evolution independently but formal considerations of both and how they relate to life history are exceedingly rare. Here, in a global biogeographical analysis of over 800 marine invertebrates, we explore the relationships between both forms of environmental predictability and three fundamental life-history traits: location of larval development (aplanktonic vs. planktonic), larval developmental mode (feeding vs. non-feeding) and offspring size. We found that both dispersal potential and offspring size related to environmental predictability, but the relationships depended on both the environmental factor as well as the type of predictability. Environments that were more seasonal in food availability had a higher prevalence of species with a planktonic larval stage. Future studies should consider both types of environmental predictability as each can strongly affect life-history evolution.

  10. Screw Remaining Life Prediction Based on Quantum Genetic Algorithm and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Xiaochen Zhang

    2017-01-01

    Full Text Available To predict the remaining life of ball screw, a screw remaining life prediction method based on quantum genetic algorithm (QGA and support vector machine (SVM is proposed. A screw accelerated test bench is introduced. Accelerometers are installed to monitor the performance degradation of ball screw. Combined with wavelet packet decomposition and isometric mapping (Isomap, the sensitive feature vectors are obtained and stored in database. Meanwhile, the sensitive feature vectors are randomly chosen from the database and constitute training samples and testing samples. Then the optimal kernel function parameter and penalty factor of SVM are searched with the method of QGA. Finally, the training samples are used to train optimized SVM while testing samples are adopted to test the prediction accuracy of the trained SVM so the screw remaining life prediction model can be got. The experiment results show that the screw remaining life prediction model could effectively predict screw remaining life.

  11. Probabilistic Remaining Useful Life Prediction of Composite Aircraft Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Probabilistic Fatigue Damage Assessment Network (PFDAN) toolkit for Abaqus will be developed for probabilistic life management of a laminated composite structure...

  12. Probabilistic Fatigue Life Prediction of Turbine Disc Considering Model Parameter Uncertainty

    Science.gov (United States)

    He, Liping; Yu, Le; Zhu, Shun-Peng; Ding, Liangliang; Huang, Hong-Zhong

    2016-06-01

    Aiming to improve the predictive ability of Walker model for fatigue life prediction and taking the turbine disc alloy GH4133 as the application example, this paper investigates a new approach for probabilistic fatigue life prediction when considering parameter uncertainty inherent in the life prediction model. Firstly, experimental data are used to update the model parameters using Bayes' theorem, so as to obtain the posterior probability distribution functions of two parameters of the Walker model, as well to achieve the probabilistic life prediction model for turbine disc. During the updating process, Markov Chain Monte Carlo (MCMC) technique is used to generate samples of the given distribution and estimating the parameters distinctly. After that, the turbine disc life is predicted using the probabilistic Walker model based on Monte Carlo simulation technique. The experimental results indicate that: (1) after using the small sample test data obtained from turbine disc, parameter uncertainty of the Walker model can be quantified and the corresponding probabilistic model for fatigue life prediction can be established using Bayes' theorem; (2) there exists obvious dispersion of life data for turbine disc when predicting fatigue life in practical engineering application.

  13. The Prediction of Fatigue Life Based on Four Point Bending Test

    NARCIS (Netherlands)

    Pramesti, F.P.; Molenaar, A.A.A.; Van de Ven, M.F.C.

    2013-01-01

    To be able to devise optimum strategies for maintenance and rehabilitation, it is essential to formulate an accurate prediction of pavement life and its maintenance needs. One of the pavement life prediction methods is based on the pavement's capability to sustain fatigue. If it were possible to hav

  14. DESIGN PROCEDURE OF SAFE LIFE AND PREDICTION OF DURABILITY OF MACHINES DETAILS AT FRICTION LOADING

    Directory of Open Access Journals (Sweden)

    В. Варюхно

    2011-04-01

    Full Text Available The aspects of prediction of durability of machines details are examined by friction loading. Onthe basis of used forecasts of change of object conditions the design procedure of safe life ofaviation engineering products, which works in conditions of friction loading. On the basis ofanalysis of the received results the theoretical model of prediction of the wear processes duringservice life is offered

  15. Does Life Satisfaction Predict Victimization Experiences in Adolescence?

    Science.gov (United States)

    Martin, Kellie; Huebner, E. Scott; Valois, Robert F.

    2008-01-01

    Longitudinal relationships between adolescents' life satisfaction and peer victimization and prosocial experiences were assessed. A total of 417 students in Grades 6-8 completed the Multidimensional Students' Life Satisfaction Scale (MSLSS: Huebner, 1994) and the Children's Social Experience Questionnaire - Self Report (SEQ-SR: Crick & Grotpeter,…

  16. Generation of Finite Life Distributional Goodman Diagrams for Reliability Prediction

    Science.gov (United States)

    Kececioglu, D.; Guerrieri, W. N.

    1971-01-01

    The methodology of developing finite life distributional Goodman diagrams and surfaces is described for presenting allowable combinations of alternating stress and mean stress to the design engineer. The combined stress condition is that of an alternating bending stress and a constant shear stress. The finite life Goodman diagrams and surfaces are created from strength distributions developed at various ratios of alternating to mean stress at particular cycle life values. The conclusions indicate that the Von Mises-Hencky ellipse, for cycle life values above 1000 cycles, is an adequate model of the finite life Goodman diagram. In addition, suggestions are made which reduce the number of experimental data points required in a fatigue data acquisition program.

  17. Prediction of Fatigue Life of Gear Subjected to Varying Loads

    Directory of Open Access Journals (Sweden)

    D. Hanumanna

    1998-07-01

    Full Text Available Structural members and components of a vehicle during service are subjected to varying loads which are random in nature. For structural members subjected to loads of constant amplitude, it is possible to describe the load with explicit mathematical relationship, and thereby, the life span can be estimated. Whereas, for structural members subjected to varying loads with time, there is no satisfactory method to estimate their life span. This paper describes a method for the estimation of life span of a gear in the gear box of a fighting vehicle subjected to fluctuating loads. For this purpose, it is assumed that the load spectrum corresponds to Gaussian (normal distribution, and the life has been worked out by applying linear cumulative damage theory.

  18. Physics-based models of the plasmasphere

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania K [Los Alamos National Laboratory; Pierrard, Vivane [BELGIUM; Goldstein, Jerry [SWRI; Andr' e, Nicolas [ESTEC/ESA; Kotova, Galina A [SRI, RUSSIA; Lemaire, Joseph F [BELGIUM; Liemohn, Mike W [U OF MICHIGAN; Matsui, H [UNIV OF NEW HAMPSHIRE

    2008-01-01

    We describe recent progress in physics-based models of the plasmasphere using the Auid and the kinetic approaches. Global modeling of the dynamics and inAuence of the plasmasphere is presented. Results from global plasmasphere simulations are used to understand and quantify (i) the electric potential pattern and evolution during geomagnetic storms, and (ii) the inAuence of the plasmasphere on the excitation of electromagnetic ion cyclotron (ElvIIC) waves a.nd precipitation of energetic ions in the inner magnetosphere. The interactions of the plasmasphere with the ionosphere a.nd the other regions of the magnetosphere are pointed out. We show the results of simulations for the formation of the plasmapause and discuss the inAuence of plasmaspheric wind and of ultra low frequency (ULF) waves for transport of plasmaspheric material. Theoretical formulations used to model the electric field and plasma distribution in the plasmasphere are given. Model predictions are compared to recent CLUSTER and MAGE observations, but also to results of earlier models and satellite observations.

  19. Global life satisfaction predicts ambulatory affect, stress, and cortisol in daily life in working adults.

    Science.gov (United States)

    Smyth, Joshua M; Zawadzki, Matthew J; Juth, Vanessa; Sciamanna, Christopher N

    2017-04-01

    Global life satisfaction has been linked with long-term health advantages, yet how life satisfaction impacts the trajectory of long-term health is unclear. This paper examines one such possible mechanism-that greater life satisfaction confers momentary benefits in daily life that accumulate over time. A community sample of working adults (n = 115) completed a measure of life satisfaction and then three subsequent days of ecological momentary assessment surveys (6 times/day) measuring affect (i.e., emotional valence, arousal), and perceived stress, and also provided salivary cortisol samples. Multilevel models indicated that people with higher (vs. lower) levels of life satisfaction reported better momentary affect, less stress, marginally lower momentary levels and significantly altered diurnal slopes of cortisol. Findings suggest individuals with high global life satisfaction have advantageous daily experiences, providing initial evidence for potential mechanisms through which global life satisfaction may help explain long-term health benefits.

  20. Extended Aging Theories for Predictions of Safe Operational Life of Critical Airborne Structural Components

    Science.gov (United States)

    Ko, William L.; Chen, Tony

    2006-01-01

    The previously developed Ko closed-form aging theory has been reformulated into a more compact mathematical form for easier application. A new equivalent loading theory and empirical loading theories have also been developed and incorporated into the revised Ko aging theory for the prediction of a safe operational life of airborne failure-critical structural components. The new set of aging and loading theories were applied to predict the safe number of flights for the B-52B aircraft to carry a launch vehicle, the structural life of critical components consumed by load excursion to proof load value, and the ground-sitting life of B-52B pylon failure-critical structural components. A special life prediction method was developed for the preflight predictions of operational life of failure-critical structural components of the B-52H pylon system, for which no flight data are available.

  1. Theory of Economic Life Prediction and Reliability Assessment of Aircraft Structures

    Institute of Scientific and Technical Information of China (English)

    YAN Chuliang; LIU Kege

    2011-01-01

    The theory of economic life prediction and reliability assessment of aircraft structures has a significant effect on safety of aircraft structures.It is based on the two-stage theory of fatigue process and can guarantee the safety and reliability of structures.According to the fatigue damage process, the fatigue scatter factors of crack initiation stage and crack propagation stage are given respectively.At the same time, mathematical models of fatigue life prediction are presented by utilizing the fatigue scatter factors and full scale test results of aircraft structures.Furthermore, the economic life model is put forward.The model is of significant scientific value for products to provide longer economic life, higher reliability and lower cost.The theory of economic life prediction and reliability assessment of aircraft structures has been successfully applied to determining and extending the structural life for thousands of airplanes.

  2. Life Prediction of Atmospheric Plasma-Sprayed Thermal Barrier Coatings Using Temperature-Dependent Model Parameters

    Science.gov (United States)

    Zhang, B.; Chen, Kuiying; Baddour, N.; Patnaik, P. C.

    2017-06-01

    The failure analysis and life prediction of atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) were carried out for a thermal cyclic process. A residual stress model for the top coat of APS-TBC was proposed and then applied to life prediction. This residual stress model shows an inversion characteristic versus thickness of thermally grown oxide. The capability of the life model was demonstrated using temperature-dependent model parameters. Using existing life data, a comparison of fitting approaches of life model parameters was performed. A larger discrepancy was found for the life predicted using linearized fitting parameters versus temperature compared to those using non-linear fitting parameters. A method for integrating the residual stress was proposed by using the critical time of stress inversion. The role of the residual stresses distributed at each individual coating layer was explored and their interplay on the coating's delamination was analyzed.

  3. A method for uncertainty quantification in the life prediction of gas turbine components

    Energy Technology Data Exchange (ETDEWEB)

    Lodeby, K.; Isaksson, O.; Jaervstraat, N. [Volvo Aero Corporation, Trolhaettan (Sweden)

    1998-12-31

    A failure in an aircraft jet engine can have severe consequences which cannot be accepted and high requirements are therefore raised on engine reliability. Consequently, assessment of the reliability of life predictions used in design and maintenance are important. To assess the validity of the predicted life a method to quantify the contribution to the total uncertainty in the life prediction from different uncertainty sources is developed. The method is a structured approach for uncertainty quantification that uses a generic description of the life prediction process. It is based on an approximate error propagation theory combined with a unified treatment of random and systematic errors. The result is an approximate statistical distribution for the predicted life. The method is applied on life predictions for three different jet engine components. The total uncertainty became of reasonable order of magnitude and a good qualitative picture of the distribution of the uncertainty contribution from the different sources was obtained. The relative importance of the uncertainty sources differs between the three components. It is also highly dependent on the methods and assumptions used in the life prediction. Advantages and disadvantages of this method is discussed. (orig.) 11 refs.

  4. Fatigue life prediction of crankshaft repaired by twin arc spraying

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-qing; WANG Cheng-tao; PU Geng-qiang

    2005-01-01

    This paper used Baumel Jr. and Seeger's approach estimating fatigue parameters of 48MnV with 3Cr13coatings. The fatigue life of the crankshaft of a six-cylinder engine, repaired by twin arc spraying 3cr13 deposits, is respectively calculated using different damage model such as S-N method, normal strain approaches, SWT-Bannantine approaches, shear strain approaches, and fatemi-Socie method based on dynamical simulation and FE analysis of crankshaft. The results indicate that the traditional calculation is conservative and that the life of crankshaft repaired by arc spraying is sufficient.

  5. Predicting the evolution of social networks with life cycle events

    OpenAIRE

    Sharmeen, F Fariya; Arentze, TA Theo; Timmermans, HJP Harry

    2015-01-01

    This paper presents a model of social network evolution, to predict and simulate changes in social networks induced by lifecycle events. We argue that social networks change with lifecycle events, and we extend a model of friendship selection to incorporate these dynamics of personal social networks. The model uses theories of homophily and reciprocity and is formulated in a random utility maximization framework to predict the formation of social ties between individuals in the population. It...

  6. Life prediction of thermal-mechanical fatigue using strain-range partitioning

    Science.gov (United States)

    Halford, G. R.; Manson, S. S.

    1975-01-01

    The applicability is described of the method of Strainrange Partitioning to the life prediction of thermal-mechanical strain-cycling fatigue. An in-phase test on 316 stainless steel is analyzed as an illustrative example. The observed life is in excellent agreement with the life predicted by the method using the recently proposed Step-Stress Method of experimental partitioning, the Interation Damage Rule, and the life relationships determined at an isothermal temperature of 705 C. Implications of the study are discussed relative to the general thermal fatigue problem.

  7. Evaluation of creep-fatigue life-prediction models for the solar central receiver

    Science.gov (United States)

    Hyzak, J. M.; Hughes, D. A.

    1981-09-01

    The applicability of several creep fatigue models to life prediction of boiler tubes in a solar central receiver (SCR) was evaluated. The SCR boiler tubes will experience compressive strain dwell loading with hold times up to 6 to 8 hours at temperatures where time dependent deformation will occur. The evaluation criteria include the ability of the model to account for mean stress effects and to be practical in the long life, small strain range regime. A correlation between maximum tensile stress and fatigue life is presented. Using this correlation, compressive dwell behavior is predicted based on continuous cycling data. The limits of this predictive scheme are addressed.

  8. Physics-Based Learning Models for Ship Hydrodynamics

    CERN Document Server

    Weymouth, Gabriel D

    2014-01-01

    We present the concepts of physics-based learning models (PBLM) and their relevance and application to the field of ship hydrodynamics. The utility of physics-based learning is motivated by contrasting generic learning models for regression predictions, which do not presume any knowledge of the system other than the training data provided with methods such as semi-empirical models, which incorporate physical insights along with data-fitting. PBLM provides a framework wherein intermediate models, which capture (some) physical aspects of the problem, are incorporated into modern generic learning tools to substantially improve the predictions of the latter, minimizing the reliance on costly experimental measurements or high-resolution high-fidelity numerical solutions. To illustrate the versatility and efficacy of PBLM, we present three wave-ship interaction problems: 1) at speed waterline profiles; 2) ship motions in head seas; and 3) three-dimensional breaking bow waves. PBLM is shown to be robust and produce ...

  9. Life prediction of advanced materials for gas turbine application

    Energy Technology Data Exchange (ETDEWEB)

    Zamrik, S.Y.; Ray, A.; Koss, D.A.

    1995-12-31

    Emphasis is placed on life characterization based on low cycle fatigue under isothermal conditions and thermomechanical fatigue. Microstructure of failed coated and uncoated specimens is being analyzed. IN 738 LC is the material; the coating is either overlay (NiCoCrAly) or NiAl-based aluminide.

  10. A Physics-based Analytical Model for Perovskite Solar Cells

    OpenAIRE

    Sun, Xingshu; Asadpour, Reza; Nie, Wanyi; Mohite, Aditya D.; Alam, Muhammad A.

    2015-01-01

    Perovskites are promising next-generation absorber materials for low-cost and high-efficiency solar cells. Although perovskite cells are configured similar to the classical solar cells, their operation is unique and requires development of a new physical model for characterization, optimization of the cells, and prediction of the panel performance. In this paper, we develop such a physics-based analytical model to describe the operation of different types of perovskite solar cells, explicitly...

  11. Physical/chemical modeling for photovoltaic module life prediction

    Science.gov (United States)

    Moacanin, J.; Carroll, W. F.; Gupta, A.

    1979-01-01

    The paper presents a generalized methodology for identification and evaluation of potential degradation and failure of terrestrial photovoltaic encapsulation. Failure progression modeling and an interaction matrix are utilized to complement the conventional approach to failure degradation mode identification. Comparison of the predicted performance based on these models can produce: (1) constraints on system or component design, materials or operating conditions, (2) qualification (predicted satisfactory function), and (3) uncertainty. The approach has been applied to an investigation of an unexpected delamination failure; it is being used to evaluate thermomechanical interactions in photovoltaic modules and to study corrosion of contacts and interconnects.

  12. Predicting professional quality of life among professional and volunteer caregivers.

    Science.gov (United States)

    Avieli, Hila; Ben-David, Sarah; Levy, Inna

    2016-01-01

    This study is one of the few that has compared volunteers' professional quality of life (PQL), which includes secondary traumatic stress (STS), burnout, and compassion satisfaction (CS), to those of professional caregivers. In addition, the research compared the ethical behavior of volunteers with that of professional therapists and examined the connection between years of experience, ethical behavior, and PQL. One hundred eighty-three volunteers and professional caregivers filled out a sociodemographic questionnaire, an Ethical Behavior Questionnaire and the Professional Quality of Life (ProQOL) questionnaire. The results indicated that professional caregivers report lower levels of STS and burnout, and higher levels of CS and ethical behavior compared with volunteer caregivers. Moreover, the findings suggest that ethical behavior correlates with STS, burnout, and CS. Ethical behavior has a protective value for mental health caregivers. The discussion emphasizes the value of a professional code of ethics and ethical training for professional and volunteering caregivers.

  13. Fatigue Life Prediction of Ductile Iron Based on DE-SVM Algorithm

    Science.gov (United States)

    Yiqun, Ma; Xiaoping, Wang; lun, An

    the model, predicting fatigue life of ductile iron, based on SVM (Support Vector Machine, SVM) has been established. For it is easy to fall into local optimum during parameter optimization of SVM, DE (Differential Evolution algorithm, DE) algorithm was adopted to optimize to improve prediction precision. Fatigue life of ductile iron is predicted combining with concrete examples, and simulation experiment to optimize SVM is conducted adopting GA (Genetic Algorithm), ACO (Ant Colony Optimization) and POS (Partial Swarm Optimization). Results reveal that DE-SVM algorithm is of a better prediction performance.

  14. Predicting quality of work life on nurses' intention to leave.

    Science.gov (United States)

    Lee, Ya-Wen; Dai, Yu-Tzu; Park, Chang-Gi; McCreary, Linda L

    2013-06-01

    The purpose of this study was to explore the relationship between quality of work life (QWL) and nurses' intention to leave their organization (ITLorg). A descriptive cross-sectional survey design was conducted using purposive sampling of 1,283 nurses at seven hospitals in Taiwan. Data were collected from March to June 2012. Three questionnaires, including the Chinese version of the Quality of Nursing Work Life scale (C-QNWL), a questionnaire of intention to leave the organization, and a demographic questionnaire, with two informed consent forms were delivered to the nurses at their workplaces. Descriptive data, Pearson's correlations, and the ordinal regression model were analyzed. Over half (52.5%) of nurses had ITLorg. Seven QWL dimensions were significantly negatively correlated with ITLorg (r = -0.17 to -0.37, p working in a nonteaching hospital. Four of the QWL dimensions--supportive milieu with job security and professional recognition, work arrangement and workload, work or home life balance, and nursing staffing and patient care--were also predictors of ITLorg. Three QWL dimensions were not predictors of ITLorg. This study showed that individual-related variables (being single, having a diploma or lower educational level), a work-related variable (working at a nonteaching hospital), and the four QWL dimensions play a significant role in nurses' ITLorg. After the QWL dimensions were added to the regression, the variance explained by the model more than doubled. To reduce nurses' ITLorg, nursing administrators may offer more focused interventions to improve the supportive milieu with job security and professional recognition, work arrangement and workload, work or home life balance, and nursing staffing and patient care. © 2013 Sigma Theta Tau International.

  15. Patterns, entropy, and predictability of human mobility and life

    CERN Document Server

    Qin, Shao-Meng; Mohtaschemi, Mikael; Hartonen, Tuomo; Alava, Mikko

    2012-01-01

    Cellular phones are now offering an ubiquitous means for scientists to observe life: how people act, move and respond to external influences. They can be utilized as measurement devices of individual persons and for groups of people of the social context and the related interactions. The picture of human life that emerges shows complexity, which is manifested in such data in properties of the spatiotemporal tracks of individuals. We extract from smartphone-based data for a set of persons important locations such as "home", "work" and so forth over fixed length time-slots covering the days in the data-set. This set of typical places is heavy-tailed, a power-law distribution with an exponent close to -1.7. To analyze the regularities and stochastic features present, the days are classified for each person into regular, personal patterns. To this are superimposed fluctuations for each day. This randomness is measured by "life" entropy, computed both before and after finding the clustering so as to subtract the c...

  16. Application of time-temperature superposition method in thermal aging life prediction of shipboard cables

    Institute of Scientific and Technical Information of China (English)

    DENG Wen-dong; CHEN Yi-yuan

    2014-01-01

    The life of shipboard cables will decrease due to the complex aging processes. In terms of the safety perspective, remaining life prediction of the cable is essential to maintain a reliable operation. In this paper, firstly, based on Arrhenius equation, residual life of new styrene-butadiene cable is calculated;result indicates that the degradation rate which changes with time is proportional to thermal temperature. Then second order dynamic model is adopted into the residual life prediction, combined with the time-temperature superposition method (TTSP), and a new residual life model is proposed. According to the accelerated thermal aging experiment data and Arrhenius equation, TTSP method demonstrates to be an efficient way for life prediction, and life at normal temperature can be estimated by this model. In order to monitor the state of styrene-butadiene cable more accurately, an improved residual life model based on equivalent environment temperature of cable is proposed, and life of cable under real operation is analyzed. Result indicates that this model is credible and reliable, and it provides an important theoretical base for residual life of cables.

  17. Life Prediction of Ball Grid Array Soldered Joints under Thermal Cycling Loading by Fracture Mechanics Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fatigue crack propagation life of ball grid array (BGA) soldered joints during thermal cycling loading was investigated by fracture mechanics approach using finite element analysis. The relationships between the strain energy release rate (G) and crack size (α), thermal cycle numbers (N) can be derived. Based on the relationships, fatigue life of the soldered joints was determined. The results showed that crack propagation life was higher than crack initiation life. Therefore, it appears that it is more appropriate to predict the fatigue life of soldered joints using the fracture mechanics method.

  18. Extreme Environment Damage Index and Accumulation Model for CMC Laminate Fatigue Life Prediction Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Materials Research & Design (MR&D) is proposing in the SBIR Phase II an effort to develop a tool for predicting the fatigue life of C/SiC composite...

  19. Study on effect of mean stress on fatigue life prediction of thin film structure

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Myung Soo [Ahtti Co., Seongnam (Korea, Republic of); Park, Jun Hyu [Tongmyong University, Busan (Korea, Republic of); Kim, Jung Yup [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2016-04-15

    This paper describes the effect of mean stress on fatigue life prediction of structure made with thin film. It is well known that the mean stress influences fatigue life prediction of mechanical structure. We investigated a reasonable method for considering mean stress when fatigue strength assessment of micro structure of thin film should be performed. Fatigue tests of smooth specimen of beryllium-copper (BeCu) thin film were performed in ambient air at R = 0.1 with 5 Hz. A micro probe was designed and made with BeCu thin film by the precision press process. Fatigue tests of micro structure were performed with 5 Hz frequency, in ambient air to verify the fatigue life predicted by computer simulation through FE analysis. The fatigue life predicted by the Sa -N curve modified by Goodman method with principal stress through FE analysis shows a more reasonable result than other methods.

  20. Physically based landslide warning at regional scale

    Science.gov (United States)

    Canli, Ekrem; Mergili, Martin; Glade, Thomas

    2017-04-01

    Albeit advancements in the past within the field of geotechnical engineering have led to an increasing in situ damage control in many parts of the world, heavy rainstorms still cause severe damage by triggering landslides. Landslides are usually restricted to the local scale when taking into consideration single events, however, they often tend to occur spatially abundant which makes them a regional phenomenon. This makes the necessity of regional-scale early warning systems (EWS) indispensable. When dealing with landslide EWS, it is impossible to cover all potential early warning situations. Although the calculation of rainfall thresholds is the most common approach for assessing regional landslide early warning, they only represent a simplification of the physical processes involved. In most cases, indeed, there is more than just this one causative factor involved. Here, we present an early prototype for a regional, physically based landslide EWS driven by real-time spatio-temporal rainfall data. Instead of assuming uniform rainfall over a certain area, an automated geostatistical approach is suggested which allows approximating real-time spatially distributed, hourly rainfall predictions based on gauged rainfall data available on the internet. The methodology presented in this study is especially suitable for the implementation in warning systems that contain predefined thresholds and for landslides related to a progressive increase of soil saturation and/or a rising groundwater table. The transient rainfall infiltration and grid-based slope stability (TRIGRS) model is used in a modified way to compute transient pore-pressure changes and associated changes in the factor of safety due to rainfall infiltration. The geotechnical properties involved are probabilistically integrated within certain predefined ranges to account for the inherent spatial uncertainties. The result is an automatically generated probability of failure raster map that is updated hourly based

  1. Physics-based deformable organisms for medical image analysis

    Science.gov (United States)

    Hamarneh, Ghassan; McIntosh, Chris

    2005-04-01

    Previously, "Deformable organisms" were introduced as a novel paradigm for medical image analysis that uses artificial life modelling concepts. Deformable organisms were designed to complement the classical bottom-up deformable models methodologies (geometrical and physical layers), with top-down intelligent deformation control mechanisms (behavioral and cognitive layers). However, a true physical layer was absent and in order to complete medical image segmentation tasks, deformable organisms relied on pure geometry-based shape deformations guided by sensory data, prior structural knowledge, and expert-generated schedules of behaviors. In this paper we introduce the use of physics-based shape deformations within the deformable organisms framework yielding additional robustness by allowing intuitive real-time user guidance and interaction when necessary. We present the results of applying our physics-based deformable organisms, with an underlying dynamic spring-mass mesh model, to segmenting and labelling the corpus callosum in 2D midsagittal magnetic resonance images.

  2. Fatigue life prediction and strength degradation of wind turbine rotor blade composites

    NARCIS (Netherlands)

    Nijssen, R.P.L.

    2006-01-01

    Wind turbine rotor blades are subjected to a large number of highly variable loads, but life predictions are typically based on constant amplitude fatigue behaviour. Therefore, it is important to determine how service life under variable amplitude fatigue can be estimated from constant amplitude fat

  3. Structural health monitoring for fatigue life prediction of orthotropic brdige decks

    NARCIS (Netherlands)

    Pijpers, R.J.M.; Pahlavan, P.L.; Paulissen, J.H.; Hakkesteegt, H.C.; Jansen, T.H.

    2013-01-01

    Infrastructure asset owners are more and more confronted with structures reaching the end of their structural life. Structural Health Monitoring (SHM) systems should provide up-to-date information about the actual condition, as well predict the structural life and required maintenance of the assets

  4. Academic Life Satisfaction Scale (ALSS) and Its Effectiveness in Predicting Academic Success

    Science.gov (United States)

    Kumar, P.K. Sudheesh; P., Dileep

    2006-01-01

    This study is undertaken to examine the effectiveness of a newly constructed psychometric instrument to assess Academic Life Satisfaction along with the components of Emotional Intelligence. The Academic Life Satisfaction Scale is used to predict the scholastic achievement as an index of Academic success. The investigators found that Academic Life…

  5. Getting What You Expect? Future Self-Views Predict the Valence of Life Events

    Science.gov (United States)

    Voss, Peggy; Kornadt, Anna E.; Rothermund, Klaus

    2017-01-01

    Views on aging have been shown to predict the occurrence of events related to physical health in previous studies. Extending these findings, we investigated the relation between aging-related future self-views and life events in a longitudinal study across a range of different life domains. Participants (N = 593, age range 30-80 years at…

  6. Submarine Propulsion Shaft Life: Probabilistic Prediction and Extension through Prevention of Water Ingress

    Science.gov (United States)

    2014-06-01

    Inspection. Reliability Engineering and System Safety , 271-292. 47 Shi, P., & Mahadevan, S. (2001). Damage Tolerance Approach for Probabilistic ...Submarine Propulsion Shaft Life: Probabilistic Prediction and Extension through Prevention of Water Ingress By Douglas E. Jonart M.S. Systems...number. 1. REPORT DATE 01 JUN 2014 2. REPORT TYPE 3. DATES COVERED 4. TITLE AND SUBTITLE Submarine Propulsion Shaft Life: Probabilistic

  7. Physics-based Modeling of Foreign Object Damage in Ceramic Matrix Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase I SBIR, Firehole Technologies will develop proof-of-concept modeling framework for a multiscale physics-based modeling tool for predicting foreign...

  8. Crack Growth Modeling and Life Prediction of Pipeline Steels Exposed to Near-Neutral pH Environments: Stage II Crack Growth and Overall Life Prediction

    Science.gov (United States)

    Zhao, Jiaxi; Chen, Weixing; Yu, Mengshan; Chevil, Karina; Eadie, Reg; Been, Jenny; Van Boven, Greg; Kania, Richard; Keane, Sean

    2017-04-01

    This investigation was initiated to provide governing equations for crack initiation, crack growth, and service life prediction of pipeline steels in near-neutral pH (NNpH) environments. This investigation develops a predictive model considering loading interactions occurring during oil and gas pipeline operation with underload-type variable pressure fluctuations. This method has predicted lifetimes comparable to the actual service lives found in the field. This is in sharp contrast with the predictions made by existing methods that are either conservative or inconsistent with the field observations. It has been demonstrated that large slash loads ( R-ratio is 0.05), often seen during gas pipeline operation, are a major life-limiting factor and should be avoided where possible. Oil pipelines have shorter lifetime because of their more frequent pressure fluctuations and larger amplitude load cycles. The accuracy of prediction can be improved if pressure data with appropriate sampling intervals are used. The sampling interval error is much larger in the prediction of oil pipelines than gas pipelines because of their different compressibility but is minimized if the pressure sampling rate for the data is at or less than one minute.

  9. Time-Delay Artificial Neural Network Computing Models for Predicting Shelf Life of Processed Cheese

    Directory of Open Access Journals (Sweden)

    Sumit Goyal

    2012-04-01

    Full Text Available This paper presents the capability of Time–delay artificial neural network models for predicting shelf life of processed cheese. Datasets were divided into two subsets (30 for training and 6 for validation. Models with single and multi layers were developed and compared with each other. Mean Square Error, Root Mean Square Error, Coefficient of Determination and Nash -
    Sutcliffo Coefficient were used as performance evaluators, Time- delay model predicted the shelf life of processed cheese as 28.25 days, which is very close to experimental shelf life of 30 days.

  10. Study of the spiritual intelligence role in predicting university students' quality of life.

    Science.gov (United States)

    Bolghan-Abadi, Mustafa; Ghofrani, Fatemeh; Abde-Khodaei, Mohammad Saeed

    2014-02-01

    The aim of the study is to investigate the spiritual intelligence role in predicting Quchan University students' quality of life. In order to collect data, a sample of 143 students of Quechan University was selected randomly enrolled for 89-90 academic year. The instruments of the data collecting are World Health Organization Quality of Life (WHOQOL) and Spiritual Intelligence Questionnaire. For analyzing the data, the standard deviation, and Pearson's correlation coefficient in descriptive level, and in inferential level, the regression test was used. The results of the study show that the spiritual intelligence has effective role on predicting quality of life.

  11. Evaluation of corrosion fatigue and life prediction of lower arm for automotive suspension component

    Science.gov (United States)

    Kim, Yong-Sang; Kim, Jung-Gu

    2017-01-01

    Lower arm is one of the suspension components of automobile. It is suffered from driving vibration and corrosive environment, namely corrosion fatigue. In this study, corrosion fatigue property of lower arm was investigated, and a modified model based on Palmgren-Miner rule was developed to predict the lifetimes of corrosion fatigue. The corrosion fatigue life of lower arm was about 1/6 times shorter than fatigue life. Based on the results of corrosion fatigue tests and meteorological data in Seoul and Halifax, the corrosion fatigue life of lower arm was predicted. The satisfaction of 10-year and 300,000 km warranty was dominated by the climate of automobile driving. This prediction indicates that the weather condition or driving condition influences the life of automotive parts. Therefore, to determine the warranty of automotive parts, the driving condition has to be carefully considered.

  12. Time Perspectives Predict Mood States and Satisfaction with Life over and above Personality.

    Science.gov (United States)

    Stolarski, Maciej; Matthews, Gerald

    2016-01-01

    The present study aimed to test the incremental validity of Time Perspective (TP) scales in predicting satisfaction with life and mood, over and above the Big Five personality traits. It also investigated whether the new TP construct of Future Negative perspective contributed to prediction of these outcomes. Participants (N = 265) completed four measures: Satisfaction With Life Scale (SWLS), UWIST Mood Adjective Checklist (UMACL), a modified Zimbardo Time Perspective Inventory (ZTPI), and NEO-Five Factor Inventory (NEO-FFI). Results confirmed the incremental validity of TP, although Big Five dimensions were independently predictive of life satisfaction and certain mood scales. Past Negative TP was the strongest single predictor of life satisfaction. However, Future Negative TP was be the strongest mood predictor from the TP universe, after controlling for the Big Five and remaining TP dimensions. Findings suggest that TP is an important aspect of personality for understanding individual differences in well-being.

  13. A new model for the life prediction of GH4133 under TMF conditions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thermal mechanical cyclic strain tests were carried out under in-phase and out-of-phase conditions on a Nickel-base Superalloy GH4133 in the temperature range of 571-823℃. Based on analyzing the present models of TMF (thermal mechanical fatigue) life prediction, a new model for predicting nickel-base superalloy TMF lifetime was proposed.TMF life of superalloy GH4133 was calculated accurately based on the new model. Experimental TMF life has been compared with the calculatedresults and all results fall in the scatter band of 1.5. The calculating results show that the new model is not only simple, but also precise. This model will play great roles in life prediction of the metal materials and the engineering components subjected to non-isothermal service conditions.

  14. LINEAR LAYER AND GENERALIZED REGRESSION COMPUTATIONAL INTELLIGENCE MODELS FOR PREDICTING SHELF LIFE OF PROCESSED CHEESE

    Directory of Open Access Journals (Sweden)

    S. Goyal

    2012-03-01

    Full Text Available This paper highlights the significance of computational intelligence models for predicting shelf life of processed cheese stored at 7-8 g.C. Linear Layer and Generalized Regression models were developed with input parameters: Soluble nitrogen, pH, Standard plate count, Yeast & mould count, Spores, and sensory score as output parameter. Mean Square Error, Root Mean Square Error, Coefficient of Determination and Nash - Sutcliffo Coefficient were used in order to compare the prediction ability of the models. The study revealed that Generalized Regression computational intelligence models are quite effective in predicting the shelf life of processed cheese stored at 7-8 g.C.

  15. Time – Delay Simulated Artificial Neural Network Models for Predicting Shelf Life of Processed Cheese

    Directory of Open Access Journals (Sweden)

    Sumit Goyal

    2012-05-01

    Full Text Available This paper highlights the significance of Time-Delay ANN models for predicting shelf life of processed cheese stored at 7-8o^C. Bayesian regularization algorithm was selected as training function. Number of neurons in single and multiple hidden layers varied from 1 to 20. The network was trained with up to 100 epochs. Mean square error, root mean square error, coefficient of determination and nash - Sutcliffe coefficient were used for calculating the prediction capability of the developed models. Time-Delay ANN models with multilayer are quite efficient in predicting the shelf life of processed cheese stored at 7-8o^C.

  16. Prediction of multiaxial fatigue life for notched specimens of titanium alloy TC4

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z. R.; Li, Z. X. [Southeast University, Nanjing (China); Hu, X. T.; Song, Y. D. [Nanjing University, Nanjing (China)

    2016-05-15

    Both the proportional and nonproportional multiaxial fatigue tests were conducted on two kinds of notched specimens of titanium alloy TC4. The multiaxial fatigue critical area of notched specimen is considered as the location experiencing the maximum damage. It is unsatisfactory to predict the multiaxial fatigue life with the local stress and strain in the fatigue critical area. The critical distance concepts are employed in the multiaxial life prediction method for notched specimens. The proposed method was checked by the test data of TC4 notched specimens. The prediction results are almost within a factor of three scatter band of the test results.

  17. Physically-based fluid animation: A survey

    Institute of Scientific and Technical Information of China (English)

    TAN Jie; YANG XuBo

    2009-01-01

    In this paper, we give an up-to-date survey on physically-based fluid animation research. As one of the most popular approaches to simulate realistic fluid effects, physically-based fluid animation has spurred a large number of new results in recent years. We classify and discuss the existing methods within three categories: Lagrangian method, Eulerian method and Lattice-Boltzmann method. We then introduce techniques for seven different kinds of special fluid effects. Finally we review the latest hot research areas and point out some future research trends, including surface tracking, fluid control, hybrid method, model reduction, etc.

  18. Condition Assessment and End-of-Life Prediction System for Electric Machines and Their Loads

    Science.gov (United States)

    Parlos, Alexander G.; Toliyat, Hamid A.

    2005-01-01

    An end-of-life prediction system developed for electric machines and their loads could be used in integrated vehicle health monitoring at NASA and in other government agencies. This system will provide on-line, real-time condition assessment and end-of-life prediction of electric machines (e.g., motors, generators) and/or their loads of mechanically coupled machinery (e.g., pumps, fans, compressors, turbines, conveyor belts, magnetic levitation trains, and others). In long-duration space flight, the ability to predict the lifetime of machinery could spell the difference between mission success or failure. Therefore, the system described here may be of inestimable value to the U.S. space program. The system will provide continuous monitoring for on-line condition assessment and end-of-life prediction as opposed to the current off-line diagnoses.

  19. TMC Behavior Modeling and Life Prediction Under Multiaxial Stresses

    Science.gov (United States)

    Merrick, H. F.; Aksoy, S. Z.; Costen, M.; Ahmad, J.

    1998-01-01

    The goal of this program was to manufacture and burst test small diameter SCS-6/Ti-6Al-4V composite rings for use in the design of an advanced titanium matrix composite (TMC) impeller. The Textron Specialty Metals grooved foil-fiber process was successfully used to make high quality TMC rings. A novel spin test arbor with "soft touch" fingers to retain the TMC ring was designed and manufactured. The design of the arbor took into account its use for cyclic experiments as well as ring burst tests. Spin testing of the instrumented ring was performed at ambient, 149C (300F), and 316C (600F) temperatures. Assembly vibration was encountered during spin testing but this was overcome through simple modification of the arbor. A spin-to-burst test was successfully completed at 316C (600F). The rotational speed of the TMC ring at burst was close to that predicted. In addition to the spin test program, a number of SCS-6/Ti-6Al-4V test panels were made. Neat Ti-6Al-4V panels also were made.

  20. Personality traits predicting quality of life and overall functioning in schizophrenia.

    Science.gov (United States)

    Ridgewell, Caitlin; Blackford, Jennifer Urbano; McHugo, Maureen; Heckers, Stephan

    2017-04-01

    Clinical symptoms and sociodemographic variables predict level of functioning and quality of life in patients with schizophrenia. However, few studies have examined the effect of personality traits on quality of life and overall functioning in schizophrenia. Personality traits are premorbid to illness and may predict the way patients experience schizophrenia. The aim of this study was to examine the individual and additive effects of two core personality traits-neuroticism and extraversion-on quality of life and functioning. Patients with schizophrenia-spectrum disorders (n=153) and healthy controls (n=125) completed personality and quality of life questionnaires. Global functioning was assessed during a clinician-administered structured interview. Neuroticism and extraversion scores were analyzed both as continuous variables and as categorical extremes (High versus Normal Neuroticism, Low versus Normal Extraversion). Quality of life was significantly associated with neuroticism, extraversion, and the neuroticism×diagnosis and extraversion×diagnosis interactions. For patients, a lower neuroticism score (in the normal range) was associated with quality of life scores comparable to controls; whereas high neuroticism scores in patients were associated with the lowest quality of life. For overall functioning, only diagnosis had a significant effect. Neuroticism modulates quality of life and may provide an important key to improving the life of patients with schizophrenia. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. A new Cumulative Damage Model for Fatigue Life Prediction under Shot Peening Treatment

    Directory of Open Access Journals (Sweden)

    Abdul-Jabar H. Ali

    2015-07-01

    Full Text Available In this paper, fatigue damage accumulation were studied using many methods i.e.Corton-Dalon (CD,Corton-Dalon-Marsh(CDM, new non-linear model and experimental method. The prediction of fatigue lifetimes based on the two classical methods, Corton-Dalon (CDandCorton-Dalon-Marsh (CDM, are uneconomic and non-conservative respectively. However satisfactory predictions were obtained by applying the proposed non-linear model (present model for medium carbon steel compared with experimental work. Many shortcomings of the two classical methods are related to their inability to take into account the surface treatment effect as shot peening. It is clear that the new model shows that a much better and conservative prediction of fatigue life in comparison with CD and CDM methods. The prediction of the present model gave slightly below the experimental data while the CDM gave overestimate prediction and CD showed strongly underestimates the life of specimens.

  2. Life prediction of coated and uncoated metallic interconnect for solid oxide fuel cell applications

    Science.gov (United States)

    Liu, W. N.; Sun, X.; Stephens, E.; Khaleel, M. A.

    In this paper, we present an integrated experimental and modeling methodology in predicting the life of coated and uncoated metallic interconnect (IC) for solid oxide fuel cell (SOFC) applications. The ultimate goal is to provide cell designer and manufacture with a predictive methodology such that the life of the IC system can be managed and optimized through different coating thickness to meet the overall cell designed life. Crofer 22 APU is used as the example IC material system. The life of coated and uncoated Crofer 22 APU under isothermal cooling was predicted by comparing the predicted interfacial strength and the interfacial stresses induced by the cooling process from the operating temperature to room temperature, together with the measured oxide scale growth kinetics. It was found that the interfacial strength between the oxide scale and the Crofer 22 APU substrate decreases with the growth of the oxide scale, and that the interfacial strength for the oxide scale/spinel coating interface is much higher than that of the oxide scale/Crofer 22 APU substrate interface. As expected, the predicted life of the coated Crofer 22 APU is significantly longer than that of the uncoated Crofer 22 APU.

  3. Validation of Framework Code Approach to a Life Prediction System for Fiber Reinforced Composites

    Science.gov (United States)

    Gravett, Phillip

    1997-01-01

    The grant was conducted by the MMC Life Prediction Cooperative, an industry/government collaborative team, Ohio Aerospace Institute (OAI) acted as the prime contractor on behalf of the Cooperative for this grant effort. See Figure I for the organization and responsibilities of team members. The technical effort was conducted during the period August 7, 1995 to June 30, 1996 in cooperation with Erwin Zaretsky, the LERC Program Monitor. Phil Gravett of Pratt & Whitney was the principal technical investigator. Table I documents all meeting-related coordination memos during this period. The effort under this grant was closely coordinated with an existing USAF sponsored program focused on putting into practice a life prediction system for turbine engine components made of metal matrix composites (MMC). The overall architecture of the NMC life prediction system was defined in the USAF sponsored program (prior to this grant). The efforts of this grant were focussed on implementing and tailoring of the life prediction system, the framework code within it and the damage modules within it to meet the specific requirements of the Cooperative. T'he tailoring of the life prediction system provides the basis for pervasive and continued use of this capability by the industry/government cooperative. The outputs of this grant are: 1. Definition of the framework code to analysis modules interfaces, 2. Definition of the interface between the materials database and the finite element model, and 3. Definition of the integration of the framework code into an FEM design tool.

  4. Development of Probabilistic Life Prediction Methodologies and Testing Strategies for MEMS and CMC's

    Science.gov (United States)

    Jadaan, Osama

    2003-01-01

    This effort is to investigate probabilistic life prediction methodologies for ceramic matrix composites and MicroElectroMechanical Systems (MEMS) and to analyze designs that determine stochastic properties of MEMS. For CMC's this includes a brief literature survey regarding lifing methodologies. Also of interest for MEMS is the design of a proper test for the Weibull size effect in thin film (bulge test) specimens. The Weibull size effect is a consequence of a stochastic strength response predicted from the Weibull distribution. Confirming that MEMS strength is controlled by the Weibull distribution will enable the development of a probabilistic design methodology for MEMS - similar to the GRC developed CARES/Life program for bulk ceramics. A main objective of this effort is to further develop and verify the ability of the Ceramics Analysis and Reliability Evaluation of Structures/Life (CARES/Life) code to predict the time-dependent reliability of MEMS structures subjected to multiple transient loads. A second set of objectives is to determine the applicability/suitability of the CARES/Life methodology for CMC analysis, what changes would be needed to the methodology and software, and if feasible, run a demonstration problem. Also important is an evaluation of CARES/Life coupled to the ANSYS Probabilistic Design System (PDS) and the potential of coupling transient reliability analysis to the ANSYS PDS.

  5. Void damage model and service life prediction for solid high polymer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the analysis of three void damage variety models, this note presents ( i ) a method that regards the void content as a damage variation of the grain and ( ii ) a geometric model for micro-unit of void damage. Equations of the void damage variety containing void content are analyzed. This work is focused on the measurement of internal damage level and the damage variety estimation is directly related to the life predication in the practical engineering applications. Nowadays, the critical service life of the solid grain/polymers is usually presumed at domestic and international level. The strength or strain reduction of 20%or the stabilizer consumption of 50% is generally regarded as a critical storage life of the solid grain/polymers, and the service life is predicted by the extrapolation method on Anhenius formula. The applications, however, show that the above method is unreliable and has significant errors. With the aid of the discontiguous automatic measuring device of real time volume deformation and void content, the master curve of void damage variety, the storage service life and the surplus life of a solid rocket grain are obtained. Since the critical storage life has been measured, and the accuracy of the service life prediction has been greatly increased. It is a novel ideal and a break-through technique.

  6. Sense of community: Dimensions predicting residential quality of life inneighbourhoods with different socioeconomic status

    Directory of Open Access Journals (Sweden)

    Isabel Hombrados-Mendieta

    2014-12-01

    Full Text Available The study aims were to identify which dimensions of the sense of community have the greatest positiveimpact on residential quality of life and which of these best predict the quality of life of residents accordingto the socioeconomic status of the neighbourhood. The study was conducted in 10 districts in Malaga City,Spain, with a total sample of 1,583 participants. Of these residents, 31% had a low socioeconomic status,34% had a medium socioeconomic status, and 35% had a high socioeconomic status. The participants wereselected using random route sampling. The results show that the 3 dimensions that best predictedresidential quality of life were the physical environment of the neighbourhood, administrative incentives,and social support from local authorities. The results also show that the dimensions of the sense ofcommunity that predicted residential quality of life changed according to the socioeconomic status of theneighbourhood. The implications of the study are discussed.

  7. Life Prediction Issues in Thermal/Environmental Barrier Coatings in Ceramic Matrix Composites

    Science.gov (United States)

    Shah, Ashwin R.; Brewer, David N.; Murthy, Pappu L. N.

    2001-01-01

    Issues and design requirements for the environmental barrier coating (EBC)/thermal barrier coating (TBC) life that are general and those specific to the NASA Ultra-Efficient Engine Technology (UEET) development program have been described. The current state and trend of the research, methods in vogue related to the failure analysis, and long-term behavior and life prediction of EBCITBC systems are reported. Also, the perceived failure mechanisms, variables, and related uncertainties governing the EBCITBC system life are summarized. A combined heat transfer and structural analysis approach based on the oxidation kinetics using the Arrhenius theory is proposed to develop a life prediction model for the EBC/TBC systems. Stochastic process-based reliability approach that includes the physical variables such as gas pressure, temperature, velocity, moisture content, crack density, oxygen content, etc., is suggested. Benefits of the reliability-based approach are also discussed in the report.

  8. Prediction of Fatigue Life of Boom Nose End Casting Using Linear Elastic Fracture Mechanics

    OpenAIRE

    Nitin D.Ghongade; Rajesh.M. Metkar

    2014-01-01

    The main objective of this study is to get the life estimation of Boom nose end casting using theoretical approach and compaired it with finite element method. Therefore, this study consists of three major sections : (1) dynamic load analysis (2) FEM and stress analysis (3) prediction of fatigue life for Boom nose end casting. In this study a dynamic loads were obtained from cyclic loading at different time. Finite element analysis was performed to obtain the variation of stress...

  9. One- and two-stage Arrhenius models for pharmaceutical shelf life prediction.

    Science.gov (United States)

    Fan, Zhewen; Zhang, Lanju

    2015-01-01

    One of the most challenging aspects of the pharmaceutical development is the demonstration and estimation of chemical stability. It is imperative that pharmaceutical products be stable for two or more years. Long-term stability studies are required to support such shelf life claim at registration. However, during drug development to facilitate formulation and dosage form selection, an accelerated stability study with stressed storage condition is preferred to quickly obtain a good prediction of shelf life under ambient storage conditions. Such a prediction typically uses Arrhenius equation that describes relationship between degradation rate and temperature (and humidity). Existing methods usually rely on the assumption of normality of the errors. In addition, shelf life projection is usually based on confidence band of a regression line. However, the coverage probability of a method is often overlooked or under-reported. In this paper, we introduce two nonparametric bootstrap procedures for shelf life estimation based on accelerated stability testing, and compare them with a one-stage nonlinear Arrhenius prediction model. Our simulation results demonstrate that one-stage nonlinear Arrhenius method has significant lower coverage than nominal levels. Our bootstrap method gave better coverage and led to a shelf life prediction closer to that based on long-term stability data.

  10. Predicting The Service Life Of Concrete Bridges Based On Quantitative Research

    Directory of Open Access Journals (Sweden)

    Gode Kristaps

    2014-10-01

    Full Text Available A new method is proposed that will help predict the remaining service life of concrete bridges based on quantitative deterioration research. It is suggested that for a given degree of damage (stage and corresponding environmental and bridge design factors, there is only one time value. In that way it is possible to calculate the deterioration rate for given environmental and bridge design factors shared by many different bridges. The method can be used to calculate the key parameters for corrosion deterioration, thereby enabling the prediction of the remaining service life of a bridge using DuraCrete deterioration models

  11. Potential of artificial neural network technology for predicting shelf life of processed cheese

    Directory of Open Access Journals (Sweden)

    Sumit Goyal

    Full Text Available Radial basis (fewer neurons artificial neural network (ANN models were developed for predicting the shelf life of processed cheese stored at 7-8o C. Mean square error, root mean square error, coefficient of determination and nash - sutcliffo coefficient were applied in order to compare the prediction ability of the developed models. Soluble nitrogen, pH; standard plate count, yeast & mouldcount, and spore count were the input parameters, while sensory score was output parameter for the developed model. The developed model showed very good correlation between actual data and predicted data with high coefficient of determination and nash - sutcliffo coefficient besides low root mean square error, suggesting that the developed model is quite efficient in predicting the shelf life of processed cheese.

  12. Application and limitations on thermal and spectroscopic methods for shelf-life prediction

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Lecon [Baxter Healthcare, Round Lake, IL 60073 (United States)]. E-mail: Wool@baxter.com; Ling, Michael T.K. [Baxter Healthcare, Round Lake, IL 60073 (United States); Eu, Bruce [Baxter Healthcare, Round Lake, IL 60073 (United States); Sandford, Craig [Baxter Healthcare, Round Lake, IL 60073 (United States)

    2006-03-15

    In medical products, shelf-life after thermoplastic processing and sterilization is important, and ionizing radiation has become a preferred sterilization mode for medical devices. We have employed successfully thermal analytical methods to predict shelf-life for many polyolefin materials. However, as the material of construction becoming more sophisticated: multiphase alloys and blends, multi-layer constructions, etc., issues existed that require clarification as to what extent these methodologies are applicable. We have employed thermal analytical methods in conjunction with other spectroscopic and morphological methods to study the applicability and limitation of these techniques. Results combined with real life and simulated aging experiments will be presented in this article.

  13. A residual life prediction model based on the generalized σ -N curved surface

    Directory of Open Access Journals (Sweden)

    Zongwen AN

    2016-06-01

    Full Text Available In order to investigate change rule of the residual life of structure under random repeated load, firstly, starting from the statistic meaning of random repeated load, the joint probability density function of maximum stress and minimum stress is derived based on the characteristics of order statistic (maximum order statistic and minimum order statistic; then, based on the equation of generalized σ -N curved surface, considering the influence of load cycles number on fatigue life, a relationship among minimum stress, maximum stress and residual life, that is the σmin(n- σmax(n-Nr(n curved surface model, is established; finally, the validity of the proposed model is demonstrated by a practical case. The result shows that the proposed model can reflect the influence of maximum stress and minimum stress on residual life of structure under random repeated load, which can provide a theoretical basis for life prediction and reliability assessment of structure.

  14. Ceramic material life prediction: A program to translate ANSYS results to CARES/LIFE reliability analysis

    Science.gov (United States)

    Vonhermann, Pieter; Pintz, Adam

    1994-01-01

    This manual describes the use of the ANSCARES program to prepare a neutral file of FEM stress results taken from ANSYS Release 5.0, in the format needed by CARES/LIFE ceramics reliability program. It is intended for use by experienced users of ANSYS and CARES. Knowledge of compiling and linking FORTRAN programs is also required. Maximum use is made of existing routines (from other CARES interface programs and ANSYS routines) to extract the finite element results and prepare the neutral file for input to the reliability analysis. FORTRAN and machine language routines as described are used to read the ANSYS results file. Sub-element stresses are computed and written to a neutral file using FORTRAN subroutines which are nearly identical to those used in the NASCARES (MSC/NASTRAN to CARES) interface.

  15. Predictive modelling for shelf life determination of nutricereal based fermented baby food.

    Science.gov (United States)

    Rasane, Prasad; Jha, Alok; Sharma, Nitya

    2015-08-01

    A shelf life model based on storage temperatures was developed for a nutricereal based fermented baby food formulation. The formulated baby food samples were packaged and stored at 10, 25, 37 and 45 °C for a test storage period of 180 days. A shelf life study was conducted using consumer and semi-trained panels, along with chemical analysis (moisture and acidity). The chemical parameters (moisture and titratable acidity) were found inadequate in determining the shelf life of the formulated product. Weibull hazard analysis was used to determine the shelf life of the product based on sensory evaluation. Considering 25 and 50 % rejection probability, the shelf life of the baby food formulation was predicted to be 98 and 322 days, 84 and 271 days, 71 and 221 days and 58 and 171 days for the samples stored at 10, 25, 37 and 45 °C, respectively. A shelf life equation was proposed using the rejection times obtained from the consumer study. Finally, the formulated baby food samples were subjected to microbial analysis for the predicted shelf life period and were found microbiologically safe for consumption during the storage period of 360 days.

  16. A computational approach for thermomechanical fatigue life prediction of dissimilarly welded superheater tubes

    Energy Technology Data Exchange (ETDEWEB)

    Krishnasamy, Ram-Kumar; Seifert, Thomas; Siegele, Dieter [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2010-07-01

    In this paper a computational approach for fatigue life prediction of dissimilarly welded superheater tubes is presented and applied to a dissimilar weld between tubes made of the nickel base alloy Alloy617 tube and the 12% chromium steel VM12. The approach comprises the calculation of the residual stresses in the welded tubes with a multi-pass dissimilar welding simulation, the relaxation of the residual stresses in a post weld heat treatment (PWHT) simulation and the fatigue life prediction using the remaining residual stresses as initial condition. A cyclic fiscoplasticity model is used to calculate the transient stresses and strains under thermocyclic service loadings. The fatigue life is predicted with a damage parameter which is based on fracture mechanics. The adjustable parameters of the model are determined based on LCF and TMF experiments. The simulations show, that the residual stresses that remain after PWHT further relax in the first loading cycles. The predicted fatigue lives depend on the residual stresses and, thus, on the choice of the loading cycle in which the damage parameter is evaluated. It the first loading cycle, where residual stresses are still present, is considered, lower fatigue lives are predicted compared to predictions considering loading cycles with relaxed residual stresses. (orig.)

  17. Looking beyond patients: Can parents' quality of life predict asthma control in children?

    Science.gov (United States)

    Cano-Garcinuño, Alfredo; Mora-Gandarillas, Isabel; Bercedo-Sanz, Alberto; Callén-Blecua, María Teresa; Castillo-Laita, José Antonio; Casares-Alonso, Irene; Forns-Serrallonga, Dolors; Tauler-Toro, Eulàlia; Alonso-Bernardo, Luz María; García-Merino, Águeda; Moneo-Hernández, Isabel; Cortés-Rico, Olga; Carvajal-Urueña, Ignacio; Morell-Bernabé, Juan José; Martín-Ibáñez, Itziar; Rodríguez-Fernández-Oliva, Carmen Rosa; Asensi-Monzó, María Teresa; Fernández-Carazo, Carmen; Murcia-García, José; Durán-Iglesias, Catalina; Montón-Álvarez, José Luis; Domínguez-Aurrecoechea, Begoña; Praena-Crespo, Manuel

    2016-07-01

    Social and family factors may influence the probability of achieving asthma control in children. Parents' quality of life has been insufficiently explored as a predictive factor linked to the probability of achieving disease control in asthmatic children. Determine whether the parents' quality of life predicts medium-term asthma control in children. Longitudinal study of children between 4 and 14 years of age, with active asthma. The parents' quality of life was evaluated using the specific IFABI-R instrument, in which scores were higher for poorer quality of life. Its association with asthma control measures in the child 16 weeks later was analyzed using multivariate methods, adjusting the effect for disease, child and family factors. The data from 452 children were analyzed (median age 9.6 years, 63.3% males). The parents' quality of life was predictive for asthma control; each point increase on the initial IFABI-R score was associated with an adjusted odds ratio (95% confidence interval) of 0.56 (0.37-0.86) for good control of asthma on the second visit, 2.58 (1.62-4.12) for asthma exacerbation, 2.12 (1.33-3.38) for an unscheduled visit to the doctor, and 2.46 (1.18-5.13) for going to the emergency room. The highest quartile for the IFABI-R score had a sensitivity of 34.5% and a specificity of 82.2% to predict poorly controlled asthma. Parents' poorer quality of life is related to poor, medium-term asthma control in children. Assessing the parents' quality of life could aid disease management decisions. Pediatr Pulmonol. 2016;51:670-677. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  18. Teachers' assessments of children aged eight predict life satisfaction in adolescence.

    Science.gov (United States)

    Honkanen, Meri; Meri, Honkanen; Hurtig, Tuula; Tuula, Hurtig; Taanila, Anja; Anja, Taanila; Moilanen, Irma; Irma, Moilanen; Koponen, Hannu; Hannu, Koponen; Mäki, Pirjo; Pirjo, Mäki; Veijola, Juha; Juha, Veijola; Puustjärvi, Anita; Anita, Puustjärvi; Ebeling, Hanna; Hanna, Ebeling; Koivumaa-Honkanen, Heli; Heli, Koivumaa-Honkanen

    2011-09-01

    The objective was to investigate how teachers' assessments of children predict life satisfaction in adolescence. This is a prospective cohort study on the population-based Northern Finland Birth Cohort 1986 (n = 8,959). Information was gathered from parents, teachers and adolescents using questionnaires at the age of 7, 8 and 15. Response rates were 80-90%. Emotional and behavioural problems were assessed with Rutter Children's Behavioural Questionnaires for teachers (RB2) and parents (RA2) during the first grade at age 8. At adolescence, self-reported life satisfaction was measured with a question including five response alternatives. According to teachers' assessments, 13.9% of the children had high emotional or behavioural problems (RB2 ≥9). These assessments predicted life dissatisfaction in adolescence (OR(crude) = 1.77; 95% CI 1.43-2.20) in several models including also health behaviour and use of psychotropic medicine. However, introducing all the significant variables in the same model, RB2 lost its significance (OR = 1.28; 0.96-1.70), but good school achievement assessed by teachers was still a significant predictor. Life satisfaction in adolescence was associated with a variety of favourable concurrent factors. In conclusion teachers' assessments of children during the first school year predicted life satisfaction in adolescence. In mental health promotion, teachers' early assessments should be utilized for the benefit of children.

  19. Development of Probabilistic Life Prediction Methodologies and Testing Strategies for MEMS

    Science.gov (United States)

    Jadaan, Osama M.

    2003-01-01

    This effort is to investigate probabilistic life prediction methodologies for MicroElectroMechanical Systems (MEMS) and to analyze designs that determine stochastic properties of MEMS. This includes completion of a literature survey regarding Weibull size effect in MEMS and strength testing techniques. Also of interest is the design of a proper test for the Weibull size effect in tensile specimens. The Weibull size effect is a consequence of a stochastic strength response predicted from the Weibull distribution. Confirming that MEMS strength is controlled by the Weibull distribution will enable the development of a probabilistic design methodology for MEMS - similar to the GRC developed CARES/Life program for bulk ceramics. Another potential item of interest is analysis and modeling of material interfaces for strength as well as developing a strategy to handle stress singularities at sharp corners, filets, and material interfaces. The ultimate objective of this effort is to further develop and verify the ability of the Ceramics Analysis and Reliability Evaluation of Structuredlife (CARES/Life) code to predict the time-dependent reliability of MEMS structures subjected to multiple transient loads. Along these lines work may also be performed on transient fatigue life prediction methodologies.

  20. Fatigue in high-speed aluminium craft: A design methodology for predicting the fatigue life

    NARCIS (Netherlands)

    Tuitman, J.T.; Hoogendoorn, D.

    2013-01-01

    Within the VOMAS project, a methodology has been developed to predict the fatigue life of high-speed aluminium crafts. This paper describes this methodology and its implementation into a computational tool. This methodology computes the seakeeping and resulting pressure at the structure for all cond

  1. SHM-Based Probabilistic Fatigue Life Prediction for Bridges Based on FE Model Updating.

    Science.gov (United States)

    Lee, Young-Joo; Cho, Soojin

    2016-03-02

    Fatigue life prediction for a bridge should be based on the current condition of the bridge, and various sources of uncertainty, such as material properties, anticipated vehicle loads and environmental conditions, make the prediction very challenging. This paper presents a new approach for probabilistic fatigue life prediction for bridges using finite element (FE) model updating based on structural health monitoring (SHM) data. Recently, various types of SHM systems have been used to monitor and evaluate the long-term structural performance of bridges. For example, SHM data can be used to estimate the degradation of an in-service bridge, which makes it possible to update the initial FE model. The proposed method consists of three steps: (1) identifying the modal properties of a bridge, such as mode shapes and natural frequencies, based on the ambient vibration under passing vehicles; (2) updating the structural parameters of an initial FE model using the identified modal properties; and (3) predicting the probabilistic fatigue life using the updated FE model. The proposed method is demonstrated by application to a numerical model of a bridge, and the impact of FE model updating on the bridge fatigue life is discussed.

  2. Acquisition and data analysis of storage tank bottoms for life prediction

    Energy Technology Data Exchange (ETDEWEB)

    Aparecido da Silva, M. [Petroquimica Uniao, Sao Paulo (Brazil); Tus, R. [Rosen Europe, Oldenzaal (Netherlands)

    2006-07-01

    Several techniques can be used to develop important life prediction information regarding structural conditions of storage tank bottoms. However, there is a limited availability of test that can be obtained from in service structural components. The reasons for applying life prediction methodology to aging storage tanks: more stringent safety and environment regulations, avoid costly forced outages, the limited availability of construction sites for new tanks, the expense of constructing, etc. The cause for applying life prediction methodology in aging tanks is material degradation. Nondestructive evaluation technique for characterizing and sizing important mechanical conditions in storage tank bottoms have been developed by the Company Rosen Inspection Technologies. The Tank Bottom Inspection Tool (TBIT) is capable to detect, data collecting and sizing in real time oriented flaws defects as well as metal loss features with length of 03 mm and depth of 50%. The technique based in high resolution MFL (Magnetic Flux Leakage) was applied in a petrochemical storage tank and compared with visual and dimensional analysis. The results show accurate information for predicting life. (orig.)

  3. Pre-transplant quality of life does not predict survival after lung transplantation

    NARCIS (Netherlands)

    Vermeulen, Karin M.; TenVergert, Elisabeth M.; Verschuuren, Erik A. M.; Erasmus, Michiel E.; van der Bij, Wim

    2008-01-01

    Background: Currently, the goal of lung transplantation is not only to improve survival but also includes' improvement of health-related quality of life (HRQL). Limited knowledge is available about the value of HRQL before lung transplantation with regard to predicting survival after lung transplant

  4. A Simple Fatigue Life Prediction Algorithm Using the Modified NASGRO Equation

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2016-01-01

    Full Text Available A simple fatigue life prediction algorithm using the modified NASGRO equation is proposed in this paper. The NASGRO equation is modified by introducing the concept of intrinsic effective threshold stress intensity factor (SIF range ΔKeffth. One advantage of the proposed method is that the complex growth behavior analysis of small cracks can be avoided, and then the fatigue life can be calculated by directly integrating the crack growth model from the initial defect size to the critical crack size. The fatigue limit and the intrinsic effective threshold SIF range ΔKeffth are used to calculate the initial defect size or initial flaw size. The value of ΔKeffth is determined by extrapolating the crack propagation rate curves. Instead of using the fatigue limit determined by the fatigue strength at the specific fatigue life, the fatigue limit is selected based on the horizontal tendency of the S-N curve. The calculated fatigue lives are compared to the experimental data of two different alloys. The predicted S-N curves agree with the test data well. Besides, the prediction results are compared with that calculated using the FASTRAN code. Results indicate that the proposed life prediction algorithm is simple and efficient.

  5. The Level of Quality of Work Life to Predict Work Alienation

    Science.gov (United States)

    Erdem, Mustafa

    2014-01-01

    The current research aims to determine the level of elementary school teachers' quality of work life (QWL) to predict work alienation. The study was designed using the relational survey model. The research population consisted of 1096 teachers employed at 25 elementary schools within the city of Van in the academic year 2010- 2011, and 346…

  6. Illness cognitions in head and neck squamous cell carcinoma: Predicting quality of life outcome

    NARCIS (Netherlands)

    M. Scharloo (Margreet); R.J.B. de Jong; T.P.M. Langeveld (ton); E. van Velzen-Verkaik (Els); M.M. den Doorn-op den Akker (Margreet); A.A. Kaptein (Adrian)

    2010-01-01

    textabstractGoals of work: This paper presents an observational study of the longitudinal effects of cancer treatment on quality of life (QoL) in patients treated for head and neck squamous cell carcinoma (HNSCC), and evaluated the contribution of patients' baseline illness cognitions to the predict

  7. The Roles of Life Satisfaction, Teaching Efficacy, and Self-Esteem in Predicting Teachers' Job Satisfaction

    Science.gov (United States)

    Çevik, Gülsen Büyüksahin

    2017-01-01

    The current research aims to find out the extent to which high school teachers' life satisfaction, teaching efficacy, and self-esteem predict their job satisfaction. Research participants included a total of 358 teachers (age = 38.82; Ss = 6.73; range, 22-58), 222 males (62%) and 136 females (38%), employed in 21 public high schools in the city…

  8. Predicting trajectories of offending over the life course : findings from a Dutch conviction cohort

    NARCIS (Netherlands)

    Bersani, B.; Nieuwbeerta, P.; Laub, J.H.

    2009-01-01

    Distinguishing trajectories of criminal offending over the life course, especially the prediction of high-rate offenders, has received considerable attention over the past two decades. Motivated by a recent study by Sampson and Laub (2003), this study uses longitudinal data on conviction histories f

  9. The Role of Life Satisfaction and Parenting Styles in Predicting Delinquent Behaviors among High School Students

    Science.gov (United States)

    Onder, Fulya Cenkseven; Yilmaz, Yasin

    2012-01-01

    The purpose of this study is to determine whether the parenting styles and life satisfaction predict delinquent behaviors frequently or not. Firstly the data were collected from 471 girls and 410 boys, a total of 881 high school students. Then the research was carried out with 502 students showing low (n = 262, 52.2%) and high level of delinquent…

  10. Life prediction methodology for thermal-mechanical fatigue and elevated temperature creep design

    Science.gov (United States)

    Annigeri, Ravindra

    Nickel-based superalloys are used for hot section components of gas turbine engines. Life prediction techniques are necessary to assess service damage in superalloy components resulting from thermal-mechanical fatigue (TMF) and elevated temperature creep. A new TMF life model based on continuum damage mechanics has been developed and applied to IN 738 LC substrate material with and without coating. The model also characterizes TMF failure in bulk NiCoCrAlY overlay and NiAl aluminide coatings. The inputs to the TMF life model are mechanical strain range, hold time, peak cycle temperatures and maximum stress measured from the stabilized or mid-life hysteresis loops. A viscoplastic model is used to predict the stress-strain hysteresis loops. A flow rule used in the viscoplastic model characterizes the inelastic strain rate as a function of the applied stress and a set of three internal stress variables known as back stress, drag stress and limit stress. Test results show that the viscoplastic model can reasonably predict time-dependent stress-strain response of the coated material and stress relaxation during hold times. In addition to the TMF life prediction methodology, a model has been developed to characterize the uniaxial and multiaxial creep behavior. An effective stress defined as the applied stress minus the back stress is used to characterize the creep recovery and primary creep behavior. The back stress has terms representing strain hardening, dynamic recovery and thermal recovery. Whenever the back stress is greater than the applied stress, the model predicts a negative creep rate observed during multiple stress and multiple temperature cyclic tests. The model also predicted the rupture time and the remaining life that are important for life assessment. The model has been applied to IN 738 LC, Mar-M247, bulk NiCoCrAlY overlay coating and 316 austenitic stainless steel. The proposed model predicts creep response with a reasonable accuracy for wide range of

  11. Reliability-based service life prediction of existing concrete structures under marine environment

    Institute of Scientific and Technical Information of China (English)

    吴灵杰; 周拥军; 寇新建; 蒋萌

    2015-01-01

    Chloride-induced corrosion of the reinforcement is considered as one of the major mechanisms resulting in the reduction of structural resistance of reinforced concrete structural elements located in marine and other aggressive environments. A study of reinforced concrete structures located at the Fangcheng dock in the Beibu Gulf port, China, was present. The result from field survey indicates that the concrete cover depth and chloride diffusion coefficient fit best normal distribution and lognormal distribution, respectively. The service life of structure is about 55 a, while initiation time is 45 a. Sensitivity analysis indicates that the most influential factor of the structure service life prediction is concrete cover, followed by diffusion coefficient, diffusion decay index, critical chloride concentration, surface chloride concentration, current density and localized pitting corrosion. Finally, the effects of diffusion decay index and critical chloride concentration on structure service life prediction are discussed.

  12. An Analytical Model for Fatigue Life Prediction Based on Fracture Mechanics and Crack Closure

    DEFF Research Database (Denmark)

    Ibsø, Jan Behrend; Agerskov, Henning

    1996-01-01

    Fatigue in steel structures subjected to stochastic loading is studied. Of special interest is the problem of fatigue damage accumulation and in this connection, a comparison between experimental results and results obtained using fracture mechanics. Fatigue test results obtained for welded plate...... test specimens are compared with fatigue life predictions using a fracture mechanics approach. In the calculation of the fatigue life, the influence of the welding residual stresses and crack closure on the fatigue crack growth is considered. A description of the crack closure model for analytical...... of the analytical fatigue lives. Both the analytical and experimental results obtained show that the Miner rule may give quite unconservative predictions of the fatigue life for the types of stochastic loading studied....

  13. Predicting life satisfaction in Angolan elderly: The moderating effect of gender

    Directory of Open Access Journals (Sweden)

    2014-03-01

    Full Text Available A considerable amount of research has been done to explain life satisfaction in the elderly, and there is growing empirical evidence on the best predictors of life satisfaction. When studying elderly's lifesatisfaction and its predictors, gender differences have been found in several studies, including significant interactions with widowhood, for example. In this context, the present study aims were: (1 to test for the gender invariance in a life satisfaction measure; (2 to predict life satisfaction using several variables related to the aging process; and (3 to test the potential moderator effects due to gender in this prediction. Participants were 1003 Angolan elderly. Several multi-group (men vs. women MIMIC structural models were tested. First, results showed that there is gender invariance for the measurement of life satisfaction. Second, results found no moderation effects on key variables of the aging process. In other words, the estimated effects of psychosocial variables on life satisfaction remain the same for both genders. The discussion relates these results to the existing literature and posits the contributions of the study.

  14. Multiaxial Fatigue Life Prediction for Steels Based on Some Simple Approximations

    Science.gov (United States)

    Li, Jing; Yao, Zhi-feng; Zhang, Zhong-ping

    2015-01-01

    The Roessle-Fatemi's hardness method (HM) and Muralidharan-Manson's modified universal slopes method (MUSM) were employed to determine the uniaxial fatigue properties of steels from easily obtained tensile properties. Both methods give good life predictions, while the Roessle-Fatemi's HM is somewhat better. Furthermore, for predicting multiaxial fatigue lives of steels in the absence of any fatigue data, the Li's modified Wang-Brown model (MWB) was used in combination with the HM method (MWB-HM) as well as the MUSM method (MWB-MUSM), respectively. Correlation between the yield strength and the Brinell hardness was also developed to estimate the multiaxial fatigue lives of steels based only on hardness and elasticity modulus. It is shown that multiaxial fatigue lives were predicted fairly well by all the methods, and the MWB-MUSM method is slightly more accurate. In addition, a computer-based procedure for multiaxial fatigue life assessment incorporating MWB-MUSM approach was proposed and implemented to predict the fatigue life of an intermediate compressor casing. The predicted results are promising.

  15. Distance saturation product predicts health–related quality of life among sarcoidosis patients

    Directory of Open Access Journals (Sweden)

    Bourbonnais Julie M

    2012-06-01

    Full Text Available Abstract Background Sarcoidosis is a chronic disease with different phenotypic manifestations. Health-related quality of life is an important aspect in sarcoidosis, yet difficult to measure. The objective of this study was to identify clinical markers predictive of poor quality of life in sarcoidosis patients that can be followed over time and targeted for intervention. Methods We assessed the quality of life of 162 patients with confirmed sarcoidosis in a prospective, cross-sectional study using the Sarcoidosis Health Questionnaire (SHQ and Short Form-36 Health Survey (SF-36. We evaluated the validity of these questionnaires and sought to identify variables that would best explain the performance scores of the patients. Results On multivariate regression analyses, the very best composite model to predict total scores from both surveys was a model containing the distance-saturation product and Borg Dyspnea Scale score at the end of a 6-min walk test. This model could better predict SF-36 scores (R2 = 0.33 than SHQ scores (R2 = 0.24. Substitution of distanced walked in 6 min for the distance-saturation product in this model resulted in a lesser ability to predict both scores (R2 = 0.26 for SF-36; R2 = 0.22 for SHQ. Conclusions Both the SHQ and SF-36 surveys are valuable tools in the assessment of health-related quality of life in sarcoidosis patients. The best model to predict quality of life among these patients, as determined by regression analyses, included the distance-saturation product and Borg score after the 6-min walk test. Both variables represent easily obtainable clinical parameters that can be followed over time and targeted for intervention.

  16. Distance saturation product predicts health-related quality of life among sarcoidosis patients.

    Science.gov (United States)

    Bourbonnais, Julie M; Malaisamy, Subramanian; Dalal, Bhavinkumar D; Samarakoon, Priyan C; Parikh, Swapna R; Samavati, Lobelia

    2012-06-13

    Sarcoidosis is a chronic disease with different phenotypic manifestations. Health-related quality of life is an important aspect in sarcoidosis, yet difficult to measure. The objective of this study was to identify clinical markers predictive of poor quality of life in sarcoidosis patients that can be followed over time and targeted for intervention. We assessed the quality of life of 162 patients with confirmed sarcoidosis in a prospective, cross-sectional study using the Sarcoidosis Health Questionnaire (SHQ) and Short Form-36 Health Survey (SF-36). We evaluated the validity of these questionnaires and sought to identify variables that would best explain the performance scores of the patients. On multivariate regression analyses, the very best composite model to predict total scores from both surveys was a model containing the distance-saturation product and Borg Dyspnea Scale score at the end of a 6-min walk test. This model could better predict SF-36 scores (R² = 0.33) than SHQ scores (R² = 0.24). Substitution of distanced walked in 6 min for the distance-saturation product in this model resulted in a lesser ability to predict both scores (R² = 0.26 for SF-36; R² = 0.22 for SHQ). Both the SHQ and SF-36 surveys are valuable tools in the assessment of health-related quality of life in sarcoidosis patients. The best model to predict quality of life among these patients, as determined by regression analyses, included the distance-saturation product and Borg score after the 6-min walk test. Both variables represent easily obtainable clinical parameters that can be followed over time and targeted for intervention.

  17. Fatigue life prediction of Ni-base thermal solar receiver tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hartrott, Philipp von; Schlesinger, Michael [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany); Uhlig, Ralf; Jedamski, Jens [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany)

    2010-07-01

    Solar receivers for tower type Solar Thermal Power Plants are subjected to complex thermo-mechanical loads including fast and severe thermo-mechanical cycles. The material temperatures can reach more than 800 C and fall to room temperature very quickly. In order to predict the fatigue life of a receiver design, receiver tubes made of Alloy 625 with a wall thickness of 0.5 mm were tested in isothermal and thermo-cyclic experiments. The number of cycles to failure was in the range of 100 to 100,000. A thermo-mechanical fatigue life prediction model was set up. The model is based on the cyclic deformation of the material and the damage caused by the growth of fatigue micro cracks. The model reasonably predicts the experimental results. (orig.)

  18. Fatigue Life Prediction of Metallic Materials Based on the Combined Nonlinear Ultrasonic Parameter

    Science.gov (United States)

    Zhang, Yuhua; Li, Xinxin; Wu, Zhenyong; Huang, Zhenfeng; Mao, Hanling

    2017-07-01

    The fatigue life prediction of metallic materials is always a tough problem that needs to be solved in the mechanical engineering field because it is very important for the secure service of mechanical components. In this paper, a combined nonlinear ultrasonic parameter based on the collinear wave mixing technique is applied for fatigue life prediction of a metallic material. Sweep experiments are first conducted to explore the influence of driving frequency on the interaction of two driving signals and the fatigue damage of specimens, and the amplitudes of sidebands at the difference frequency and sum frequency are tracked when the driving frequency changes. Then, collinear wave mixing tests are carried out on a pair of cylindrically notched specimens with different fatigue damage to explore the relationship between the fatigue damage and the relative nonlinear parameters. The experimental results show when the fatigue degree is below 65% the relative nonlinear parameter increases quickly, and the growth rate is approximately 130%. If the fatigue degree is above 65%, the increase in the relative nonlinear parameter is slow, which has a close relationship with the microstructure evolution of specimens. A combined nonlinear ultrasonic parameter is proposed to highlight the relationship of the relative nonlinear parameter and fatigue degree of specimens; the fatigue life prediction model is built based on the relationship, and the prediction error is below 3%, which is below the prediction error based on the relative nonlinear parameters at the difference and sum frequencies. Therefore, the combined nonlinear ultrasonic parameter using the collinear wave mixing method can effectively estimate the fatigue degree of specimens, which provides a fast and convenient method for fatigue life prediction.

  19. Fatigue Life Prediction of Metallic Materials Based on the Combined Nonlinear Ultrasonic Parameter

    Science.gov (United States)

    Zhang, Yuhua; Li, Xinxin; Wu, Zhenyong; Huang, Zhenfeng; Mao, Hanling

    2017-08-01

    The fatigue life prediction of metallic materials is always a tough problem that needs to be solved in the mechanical engineering field because it is very important for the secure service of mechanical components. In this paper, a combined nonlinear ultrasonic parameter based on the collinear wave mixing technique is applied for fatigue life prediction of a metallic material. Sweep experiments are first conducted to explore the influence of driving frequency on the interaction of two driving signals and the fatigue damage of specimens, and the amplitudes of sidebands at the difference frequency and sum frequency are tracked when the driving frequency changes. Then, collinear wave mixing tests are carried out on a pair of cylindrically notched specimens with different fatigue damage to explore the relationship between the fatigue damage and the relative nonlinear parameters. The experimental results show when the fatigue degree is below 65% the relative nonlinear parameter increases quickly, and the growth rate is approximately 130%. If the fatigue degree is above 65%, the increase in the relative nonlinear parameter is slow, which has a close relationship with the microstructure evolution of specimens. A combined nonlinear ultrasonic parameter is proposed to highlight the relationship of the relative nonlinear parameter and fatigue degree of specimens; the fatigue life prediction model is built based on the relationship, and the prediction error is below 3%, which is below the prediction error based on the relative nonlinear parameters at the difference and sum frequencies. Therefore, the combined nonlinear ultrasonic parameter using the collinear wave mixing method can effectively estimate the fatigue degree of specimens, which provides a fast and convenient method for fatigue life prediction.

  20. Prediction of the Service Life of a Reinforced Concrete Column under Chloride Environment

    Directory of Open Access Journals (Sweden)

    Mohammad K. Alkam

    2015-01-01

    Full Text Available In the present investigation, service life of a reinforced concrete column exposed to chloride environment has been predicted. This study has been based on numerical simulation of chloride ion diffusion in a concrete column during its anticipated life span. The simulation process has included the concrete cover replacement whenever chloride ion concentration has reached the critical threshold value at the reinforcement surface. Repair scheduling of the concrete column under consideration has been discussed. Effects of the concrete cover thickness and the water cement ratio on the service life of the concrete column at hand have been presented. A new approach for arranging locations of reinforcement steel bars has been introduced. This approach is intended to prolong the service life of the concrete column under consideration against chloride induced corrosion.

  1. Fatigue Life Prediction of Horizontal Press Frame Based on Statistical Probability and Its Redesign

    Institute of Scientific and Technical Information of China (English)

    WeiWei Zhang; XiaoSon Wang; Bo Yang; Shi-Jian Yuan

    2014-01-01

    Horizontal press as an important part of hydro-forming machine is used to output the horizontal force to keep the high internal pressure during tube hydro-forming. However, the horizontal press frame is usually mounted on the press bed and not pre-stressed. Meanwhile it will be subjected to the reaction force caused by liquid pressure. Stresses are concentrated severely on the assemble region due to deformation, and total fatigue life will decrease. In order to predict the total fatigue life of the frame, the simulations are used firstly to determine to stress concentration region, and then strain gauge measurements are carried out under different loads. Next, the methods of statistical probability are conducted to calculate the fatigue life based on long-term load history. Finally a structure with the considerable longer fatigue life is redesigned.

  2. An Analytical Model for Fatigue Life Prediction Based on Fracture Mechanics and Crack Closure

    DEFF Research Database (Denmark)

    Ibsø, Jan Behrend; Agerskov, Henning

    1996-01-01

    Fatigue in steel structures subjected to stochastic loading is studied. Of special interest is the problem of fatigue damage accumulation and in this connection, a comparison between experimental results and results obtained using fracture mechanics. Fatigue test results obtained for welded plate...... test specimens are compared with fatigue life predictions using a fracture mechanics approach. In the calculation of the fatigue life, the influence of the welding residual stresses and crack closure on the fatigue crack growth is considered. A description of the crack closure model for analytical...... determination of the fatigue life is included. Furthermore, the results obtained in studies of the various parameters that have an influence on the fatigue life, are given. A very good agreement between experimental and analytical results is obtained, when the crack closure model is used in determination...

  3. Physically based modeling and animation of tornado

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-guang; WANG Zhang-ye; GONG Zheng; CHEN Fei-fei; PENG Qun-sheng

    2006-01-01

    Realistic modeling and rendering of dynamic tornado scene is recognized as a challenging task for researchers of computer graphics. In this paper a new physically based method for simulating and animating tornado scene is presented. We first propose a Two-Fluid model based on the physical theory of tornado, then we simulate the flow of tornado and its interaction with surrounding objects such as debris, etc. Taking the scattering and absorption of light by the participating media into account, the illumination effects of the tornado scene can be generated realistically. With the support of graphics hardware, various kinds of dynamic tornado scenes can be rendered at interactive rates.

  4. Physical activity predicts quality of life and happiness in children and adolescents with cerebral palsy.

    Science.gov (United States)

    Maher, Carol Ann; Toohey, Monica; Ferguson, Monika

    2016-01-01

    To examine the associations between physical activity, health-related quality of life and happiness in young people with cerebral palsy. A total of 70 young people with cerebral palsy (45 males, 25 females; mean age 13 years 11 months, SD 2 years 0 month) took part in a cross-sectional, descriptive postal survey assessing physical activity (Physical Activity Questionnaire for Adolescents), functional ability (Gross Motor Function Classification System), quality of life (Pediatric Quality of Life Inventory 4.0) and happiness (single Likert-scale item). Relationships between physical activity, quality of life and happiness were examined using backward stepwise linear regression. Physical activity significantly predicted physical quality of life (R(2 )= 0.64, β = 6.12, p = 0.02), social quality of life (R(2 )= 0.28, β = 9.27, p happiness (R(2 )= 0.08, β = 0.9, p = 0.04). Physical activity was not associated with emotional or school quality of life. This study found a positive association between physical activity, social and physical quality of life, and happiness in young people with cerebral palsy. Findings underscore the potential benefits of physical activity for the wellbeing of young people with cerebral palsy, in addition to its well-recognised physical and health benefits. Physical activity is a key predictor of quality of life and happiness in young people with cerebral palsy. Physical activity is widely recognised as having physical health benefits for young people with cerebral palsy; however, this study also highlights that it may have important benefits for wellbeing, quality of life and happiness. This emphasises the need for clinical services and intervention studies aimed specifically at increasing physical activity amongst children and adolescents with cerebral palsy.

  5. Shelf-life prediction of canned "nasi uduk" using accelerated shelf-life test (ASLT) - Arrhenius model

    Science.gov (United States)

    Kurniadi, Muhamad; Salam, Nur; Kusumaningrum, Annisa; Nursiwi, Asri; Angwar, Mukhamad; Susanto, Agus; Nurhikmat, Asep; Triwiyono, Frediansyah, Andri

    2017-01-01

    "Nasi Uduk" is one of the Indonesian traditional food made from rice, steamed with coconut milk and seasoning. For optimizing shelf-life, canned "nasi uduk" for military and disaster-response ration, was packed using cylindrical cans of 72,63 × 53,04 mm (Ø × h) in size. One of the important aspects on quality assessment of preserved product was its rancidity. The aim of this research was to determine shelf-life of canned "nasi uduk" using ASLT method of Arrhenius model. Storage temperatures set up at 35, 45 and 55°C for 35 days. Optimization of sterilization process was conducted to achieve the optimum conditions of sterilization. Target lethality value (Fo), microorganism total plate count (TPC) and rancidity levels (TBA) were used as parameters in this research. The results showed that the optimum sterilization conditions were 121 °C for 20 minutes, TPC value of 9.5 × 101 CFU/ml and Fo value 4.14 minutes. Predicted shelf-life of canned "nasi uduk" was 9.6 months which was average TBA value still bellow of the critical point.

  6. Predictive Modeling for End-of-Life Pain Outcome using Electronic Health Records

    Science.gov (United States)

    Lodhi, Muhammad K.; Stifter, Janet; Yao, Yingwei; Ansari, Rashid; Kee-nan, Gail M.; Wilkie, Diana J.; Khokhar, Ashfaq A.

    2016-01-01

    Electronic health record (EHR) systems are being widely used in the healthcare industry nowadays, mostly for monitoring the progress of the patients. EHR data analysis has become a big data problem as data is growing rapidly. Using a nursing EHR system, we built predictive models for determining what factors influence pain in end-of-life (EOL) patients. Utilizing different modeling techniques, we developed coarse-grained and fine-grained models to predict patient pain outcomes. The coarse-grained models help predict the outcome at the end of each hospitalization, whereas fine-grained models help predict the outcome at the end of each shift, thus providing a trajectory of predicted outcomes over the entire hospitalization. These models can help in determining effective treatments for individuals and groups of patients and support standardization of care where appropriate. Using these models may also lower the cost and increase the quality of end-of-life care. Results from these techniques show significantly accurate predictions. PMID:27500287

  7. Lithium-ion battery remaining useful life prediction based on grey support vector machines

    Directory of Open Access Journals (Sweden)

    Xiaogang Li

    2015-12-01

    Full Text Available In this article, an improved grey prediction model is proposed to address low-accuracy prediction issue of grey forecasting model. The first step is using a trigonometric function to transform the original data sequence to smooth the data, which is called smoothness of grey prediction model, and then a grey support vector machine model by integrating the improved grey model with support vector machine is introduced. At the initial stage of the model, trigonometric functions and accumulation generation operation can be used to preprocess the data, which enhances the smoothness of the data and reduces the associated randomness. In addition, support vector machine is implemented to establish a prediction model for the pre-processed data and select the optimal model parameters via genetic algorithms. Finally, the data are restored through the ‘regressive generate’ operation to obtain the forecasting data. To prove that the grey support vector machine model is superior to the other models, the battery life data from the Center for Advanced Life Cycle Engineering are selected, and the presented model is used to predict the remaining useful life of the battery. The predicted result is compared to that of grey model and support vector machines. For a more intuitive comparison of the three models, this article quantifies the root mean square errors for these three different models in the case of different ratio of training samples and prediction samples. The results show that the effect of grey support vector machine model is optimal, and the corresponding root mean square error is only 3.18%.

  8. Renal parenchymal histopathology predicts life-threatening chronic kidney disease as a result of radical nephrectomy.

    Science.gov (United States)

    Sejima, Takehiro; Honda, Masashi; Takenaka, Atsushi

    2015-01-01

    The preoperative prediction of post-radical nephrectomy renal insufficiency plays an important role in the decision-making process regarding renal surgery options. Furthermore, the prediction of both postoperative renal insufficiency and postoperative cardiovascular disease occurrence, which is suggested to be an adverse consequence caused by renal insufficiency, contributes to the preoperative policy decision as well as the precise informed consent for a renal cell carcinoma patient. Preoperative nomograms for the prediction of post-radical nephrectomy renal insufficiency, calculated using patient backgrounds, are advocated. The use of these nomograms together with other types of nomograms predicting oncological outcome is beneficial. Post-radical nephrectomy attending physicians can predict renal insufficiency based on the normal renal parenchymal pathology in addition to preoperative patient characteristics. It is suggested that a high level of global glomerulosclerosis in nephrectomized normal renal parenchyma is closely associated with severe renal insufficiency. Some studies showed that post-radical nephrectomy severe renal insufficiency might have an association with increased mortality as a result of cardiovascular disease. Therefore, such pathophysiology should be recognized as life-threatening, surgically-related chronic kidney disease. On the contrary, the investigation of the prediction of mild post-radical nephrectomy renal insufficiency, which is not related to adverse consequences in the postoperative long-term period, is also promising because the prediction of mild renal insufficiency might be the basis for the substitution of radical nephrectomy for nephron-sparing surgery in technically difficult or compromised cases. The deterioration of quality of life caused by post-radical nephrectomy renal insufficiency should be investigated in conjunction with life-threatening matters.

  9. Creep Rupture Life Prediction Based on Analysis of Large Creep Deformation

    Directory of Open Access Journals (Sweden)

    YE Wenming

    2016-08-01

    Full Text Available A creep rupture life prediction method for high temperature component was proposed. The method was based on a true stress-strain elastoplastic creep constitutive model and the large deformation finite element analysis method. This method firstly used the high-temperature tensile stress-strain curve expressed by true stress and strain and the creep curve to build materials' elastoplastic and creep constitutive model respectively, then used the large deformation finite element method to calculate the deformation response of high temperature component under a given load curve, finally the creep rupture life was determined according to the change trend of the responsive curve.The method was verified by durable test of TC11 titanium alloy notched specimens under 500 ℃, and was compared with the three creep rupture life prediction methods based on the small deformation analysis. Results show that the proposed method can accurately predict the high temperature creep response and long-term life of TC11 notched specimens, and the accuracy is better than that of the methods based on the average effective stress of notch ligament, the bone point stress and the fracture strain of the key point, which are all based on small deformation finite element analysis.

  10. Measurement techniques and instruments suitable for life-prediction testing of photovoltaic arrays. Interim report

    Energy Technology Data Exchange (ETDEWEB)

    Noel, G.T.; Sliemers, F.A.; Deringer, G.C.; Wood, V.E.; Wilkes, K.E.; Gaines, G.B.; Carmichael, D.C.

    1978-01-15

    The validation of a service life of 20 years for low-cost photovoltaic arrays must be accomplished through accelerated life-prediction tests. A methodology for such tests has been developed in a preceding study. The results discussed consist of the initial identification and assessment of all known measurement techniques and instruments that might be used in these life-prediction tests. Array failure modes, relevant materials property changes, and primary degradation mechanisms are discussed as a prerequisite to identifying suitable measurement techniques and instruments. Candidate techniques and instruments are identified on the basis of extensive reviews of published and unpublished information. These methods are organized in six measurement categories--chemical, electrical, optical, thermal, mechanical, and ''other physicals''. Using specified evaluation criteria, the most promising techniques and instruments for use in life-prediction tests of arrays are then selected. These recommended techniques and their characteristics are described. Recommendations are made regarding establishment of the adequacy, particularly with respect to precision, of the more fully developed techniques for this application, and regarding the experimental evaluation of promising developmental techniques. Measurement needs not satisfied by presently available techniques/instruments are also identified.

  11. Life Predicted in a Probabilistic Design Space for Brittle Materials With Transient Loads

    Science.gov (United States)

    Nemeth, Noel N.; Palfi, Tamas; Reh, Stefan

    2005-01-01

    Analytical techniques have progressively become more sophisticated, and now we can consider the probabilistic nature of the entire space of random input variables on the lifetime reliability of brittle structures. This was demonstrated with NASA s CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code combined with the commercially available ANSYS/Probabilistic Design System (ANSYS/PDS), a probabilistic analysis tool that is an integral part of the ANSYS finite-element analysis program. ANSYS/PDS allows probabilistic loads, component geometry, and material properties to be considered in the finite-element analysis. CARES/Life predicts the time dependent probability of failure of brittle material structures under generalized thermomechanical loading--such as that found in a turbine engine hot-section. Glenn researchers coupled ANSYS/PDS with CARES/Life to assess the effects of the stochastic variables of component geometry, loading, and material properties on the predicted life of the component for fully transient thermomechanical loading and cyclic loading.

  12. Physics based Prediction of Unexploded Ordnance Penetration in Granular Materials

    Science.gov (United States)

    2017-05-01

    5.3.5 Coefficient of Restitution .......................................................................... 72 XII 5.4 Simulation of Pluviation...penetrated projectile in test 1 and the formed crater: plan view (dimensions in mm...projectile in test 2 and the formed crater: plan view (dimensions in mm

  13. [Measured and Predicted Aquatic Life Criteria and Risk Assessment of Chromium (VI) in Liaohe River].

    Science.gov (United States)

    Wang, Xiao-nan; Yan, Zhen-guang; Liu, Zheng-tao; Zhang, Cong; Wang, Wei-li

    2015-07-01

    In this study, toxicity data of aquatic species in Liaohe River for heavy metal chromium (VI) was collected and selected. The aquatic life criteria for chromium (VI) in Liaohe River was derived based on these toxicity data. Moreover, water samples of 25 sites in Liaohe River were collected, and the concentrations of chromium (VI) in these samples were analyzed. Finally, ecological risk assessment of chromium (VI) in Liaohe River was performed. Moreover, interspecies correlation estimation method (ICE) established by US EPA was used to predict the acute toxicity of species in Liaohe River, and aquatic life criteria based on predicted toxicity data was derived. The results showed that: the measured CMC (criteria maximum concentration), measured CCC (criteria continuous concentration) and the predicted CMC were 17. 73, 12. 15 and 13. 97 µg . L -1, respectively. Therefore, the ICE method could be used to predict the aquatic life criteria, because the predicted criteria value was very similar to the measured criteria value. Analysis of chromium (V) showed that the chromium (VI) concentrations of the 25 sites in Liaohe River were all below Class I or Class II water quality standards (GB 3838-2002), and the water quality was in good condition. However, for the potential risk of chromium (VI) exposure to the aquatic life of Liaohe River, the result of ecological risk assessment showed that chromium (V) concentrations in 7 sites exceeded the CCC in July, and chromium (VI) concentrations in 6 sites exceeded the CCC in December. Therefore, unacceptable effect on aquatic species caused by chromium (VI) exposure might have occurred in some sites of Liaohe River.

  14. The prediction technology study of fatigue life for key parts of a tracked vehicle's suspension system

    Institute of Scientific and Technical Information of China (English)

    WANG Hongyan; RUI Qiang; HE Xiaojun

    2007-01-01

    In allusion to fatigue life of a tracked vehicle torsion bar, a virtual prototype model of the tracked vehicle suspension system including a flexible torsion bar was built based on dynamic simulation software-ADAMS. Node force and stress results of the torsion bar from last step simu- lation were acquired; taking into account the material charac- teristics and influential factors, fatigue life of the flexible body. of the torsion bar was predicted. Engineering results can be acquired through the contrast of the result of virtual test and statistical fatigue.

  15. Does life satisfaction predict five-year mortality in community-living older adults?

    Science.gov (United States)

    St John, Philip D; Mackenzie, Corey; Menec, Verena

    2015-01-01

    Depression and depressive symptoms predict death, but it is less clear if more general measures of life satisfaction (LS) predict death. Our objectives were to determine: (1) if LS predicts mortality over a five-year period in community-living older adults; and (2) which aspects of LS predict death. 1751 adults over the age of 65 who were living in the community were sampled from a representative population sampling frame in 1991/1992 and followed five years later. Age, gender, and education were self-reported. An index of multimorbidity and the Older American Resource Survey measured health and functional status, and the Terrible-Delightful Scale assessed overall LS as well as satisfaction with: health, finances, family, friends, housing, recreation, self-esteem, religion, and transportation. Cox proportional hazards models examined the influence of LS on time to death. 417 participants died during the five-year study period. Overall LS and all aspects of LS except finances, religion, and self-esteem predicted death in unadjusted analyses. In fully adjusted analyses, LS with health, housing, and recreation predicted death. Other aspects of LS did not predict death after accounting for functional status and multimorbidity. LS predicted death, but certain aspects of LS are more strongly associated with death. The effect of LS is complex and may be mediated or confounded by health and functional status. It is important to consider different domains of LS when considering the impact of this important emotional indicator on mortality among older adults.

  16. Slow Crack Growth and Fatigue Life Prediction of Ceramic Components Subjected to Variable Load History

    Science.gov (United States)

    Jadaan, Osama

    2001-01-01

    Present capabilities of the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code include probabilistic life prediction of ceramic components subjected to fast fracture, slow crack growth (stress corrosion), and cyclic fatigue failure modes. Currently, this code has the capability to compute the time-dependent reliability of ceramic structures subjected to simple time-dependent loading. For example, in slow crack growth (SCG) type failure conditions CARES/Life can handle the cases of sustained and linearly increasing time-dependent loads, while for cyclic fatigue applications various types of repetitive constant amplitude loads can be accounted for. In real applications applied loads are rarely that simple, but rather vary with time in more complex ways such as, for example, engine start up, shut down, and dynamic and vibrational loads. In addition, when a given component is subjected to transient environmental and or thermal conditions, the material properties also vary with time. The objective of this paper is to demonstrate a methodology capable of predicting the time-dependent reliability of components subjected to transient thermomechanical loads that takes into account the change in material response with time. In this paper, the dominant delayed failure mechanism is assumed to be SCG. This capability has been added to the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code, which has also been modified to have the ability of interfacing with commercially available FEA codes executed for transient load histories. An example involving a ceramic exhaust valve subjected to combustion cycle loads is presented to demonstrate the viability of this methodology and the CARES/Life program.

  17. A Mathematical Model for Predicting the Life of PEM Fuel Cell Membranes Subjected to Hydration Cycling

    CERN Document Server

    Burlatsky, S F; O'Neill, J; Atrazhev, V V; Varyukhin, A N; Dmitriev, D V; Erikhman, N S

    2013-01-01

    Under typical PEM fuel cell operating conditions, part of membrane electrode assembly is subjected to humidity cycling due to variation of inlet gas RH and/or flow rate. Cyclic membrane hydration/dehydration would cause cyclic swelling/shrinking of the unconstrained membrane. In a constrained membrane, it causes cyclic stress resulting in mechanical failure in the area adjacent to the gas inlet. A mathematical modeling framework for prediction of the lifetime of a PEM FC membrane subjected to hydration cycling is developed in this paper. The model predicts membrane lifetime as a function of RH cycling amplitude and membrane mechanical properties. The modeling framework consists of three model components: a fuel cell RH distribution model, a hydration/dehydration induced stress model that predicts stress distribution in the membrane, and a damage accrual model that predicts membrane life-time. Short descriptions of the model components along with overall framework are presented in the paper. The model was used...

  18. Predicting US Infants' and Toddlers' TV/Video Viewing Rates: Mothers' Cognitions and Structural Life Circumstances.

    Science.gov (United States)

    Vaala, Sarah E; Hornik, Robert C

    2014-04-01

    There has been rising international concern over media use with children under two. As little is known about the factors associated with more or less viewing among very young children, this study examines maternal factors predictive of TV/video viewing rates among American infants and toddlers. Guided by the Integrative Model of Behavioral Prediction, this survey study examines relationships between children's rates of TV/video viewing and their mothers' structural life circumstances (e.g., number of children in the home; mother's screen use), and cognitions (e.g., attitudes; norms). Results suggest that mothers' structural circumstances and cognitions respectively contribute independent explanatory power to the prediction of children's TV/video viewing. Influence of structural circumstances is partially mediated through cognitions. Mothers' attitudes as well as their own TV/video viewing behavior were particularly predictive of children's viewing. Implications of these findings for international efforts to understand and reduce infant/toddler TV/video exposure are discussed.

  19. Wealth and happiness across the world: material prosperity predicts life evaluation, whereas psychosocial prosperity predicts positive feeling.

    Science.gov (United States)

    Diener, Ed; Ng, Weiting; Harter, James; Arora, Raksha

    2010-07-01

    The Gallup World Poll, the first representative sample of planet Earth, was used to explore the reasons why happiness is associated with higher income, including the meeting of basic needs, fulfillment of psychological needs, increasing satisfaction with one's standard of living, and public goods. Across the globe, the association of log income with subjective well-being was linear but convex with raw income, indicating the declining marginal effects of income on subjective well-being. Income was a moderately strong predictor of life evaluation but a much weaker predictor of positive and negative feelings. Possessing luxury conveniences and satisfaction with standard of living were also strong predictors of life evaluation. Although the meeting of basic and psychological needs mediated the effects of income on life evaluation to some degree, the strongest mediation was provided by standard of living and ownership of conveniences. In contrast, feelings were most associated with the fulfillment of psychological needs: learning, autonomy, using one's skills, respect, and the ability to count on others in an emergency. Thus, two separate types of prosperity-economic and social psychological-best predict different types of well-being.

  20. Life prediction methodology for ceramic components of advanced vehicular heat engines: Volume 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Khandelwal, P.K.; Provenzano, N.J.; Schneider, W.E. [Allison Engine Co., Indianapolis, IN (United States)

    1996-02-01

    One of the major challenges involved in the use of ceramic materials is ensuring adequate strength and durability. This activity has developed methodology which can be used during the design phase to predict the structural behavior of ceramic components. The effort involved the characterization of injection molded and hot isostatic pressed (HIPed) PY-6 silicon nitride, the development of nondestructive evaluation (NDE) technology, and the development of analytical life prediction methodology. Four failure modes are addressed: fast fracture, slow crack growth, creep, and oxidation. The techniques deal with failures initiating at the surface as well as internal to the component. The life prediction methodology for fast fracture and slow crack growth have been verified using a variety of confirmatory tests. The verification tests were conducted at room and elevated temperatures up to a maximum of 1371 {degrees}C. The tests involved (1) flat circular disks subjected to bending stresses and (2) high speed rotating spin disks. Reasonable correlation was achieved for a variety of test conditions and failure mechanisms. The predictions associated with surface failures proved to be optimistic, requiring re-evaluation of the components` initial fast fracture strengths. Correlation was achieved for the spin disks which failed in fast fracture from internal flaws. Time dependent elevated temperature slow crack growth spin disk failures were also successfully predicted.

  1. FATIGUE LIFE PREDICTION OF COMMERCIALLY PURE TITANIUM AFTER NITROGEN ION IMPLANTATION

    Directory of Open Access Journals (Sweden)

    Nurdin Ali

    2013-06-01

    Full Text Available Prediction of fatigue life has become an interesting issue in biomaterial engineering and design for reliability and quality purposes, particularly for biometallic material with modified surfaces. Commercially pure titanium (Cp-Ti implanted with nitrogen ions is a potential metallic biomaterial of the future. The effect of nitrogen ion implantation on fatigue behavior of Cp-Ti was investigated by means of axial loading conditions. The as-received and nitrogen-ion implanted specimens with the energy of 100 keV and dose of 2 × 1017 ions cm-2, were used to determine the fatigue properties and to predict the life cycle of the specimens. The effect of nitrogen ion implantation indicated revealed improved the tensile strength due to the formation of nitride phases, TiN and Ti2N. The fatigue strength of Cp-Ti and Nii-Ti was 250 and 260 MPa, respectively. The analytical results show good agreement with experimental results.

  2. Anisotropic Elastoplastic Damage Mechanics Method to Predict Fatigue Life of the Structure

    Directory of Open Access Journals (Sweden)

    Hualiang Wan

    2016-01-01

    Full Text Available New damage mechanics method is proposed to predict the low-cycle fatigue life of metallic structures under multiaxial loading. The microstructure mechanical model is proposed to simulate anisotropic elastoplastic damage evolution. As the micromodel depends on few material parameters, the present method is very concise and suitable for engineering application. The material parameters in damage evolution equation are determined by fatigue experimental data of standard specimens. By employing further development on the ANSYS platform, the anisotropic elastoplastic damage mechanics-finite element method is developed. The fatigue crack propagation life of satellite structure is predicted using the present method and the computational results comply with the experimental data very well.

  3. Service Life Prediction of Wood Claddings by in-situ Measurement of Wood Moisture Content

    DEFF Research Database (Denmark)

    Engelund, Emil Tang; Lindegaard, Berit; Morsing, Niels

    2009-01-01

    The Danish Technological Institute is in co-operation with industry partners running a project aiming at predicting the service life of different wood protecting systems. The project focuses on examining the moisture reducing effect of different protecting systems for timber claddings...... and the ability of these to maintain the appearance of the surfaces, when the wood is used in service class 3 (EN 335-1 1992). A façade construction is exposed to weathering at the field test area of the Danish Technological Institute (near Copenhagen). In specific locations of the construction measurements...... of wood moisture are done by in-situ resistance moisture meters (Lindegaard and Morsing 2006). The aim is that the test should form the basis of evaluation of the maintenance requirements and the prediction of service life of the surface treatment and the wood/construction. At the moment 60 test racks...

  4. Bi-variable damage model for fatigue life prediction of metal components

    Institute of Scientific and Technical Information of China (English)

    Miao Zhang; Qing-Chun Meng; Xing Zhang; Wei-Ping Hu

    2011-01-01

    Based on the theory of continuum damage mechanics, a bi-variable damage mechanics model is developed, which, according to thermodynamics, is accessible to derivation of damage driving force, damage evolution equation and damage evolution criteria. Furthermore, damage evolution equations of time rate are established by the generalized Drucker's postulate. The damage evolution equation of cycle rate is obtained by integrating the time damage evolution equations, and the fatigue life prediction method for smooth specimens under repeated loading with constant strain amplitude is constructed. Likewise, for notched specimens under the repeated loading with constant strain amplitude, the fatigue life prediction method is obtained on the ground of the theory of conservative integral in damage mechanics. Thus, the material parameters in the damage evolution equation can be obtained by reference to the fatigue test results of standard specimens with stress concentration factor equal to 1, 2 and 3.

  5. Basic traits predict the prevalence of personality disorder across the life span: the example of psychopathy.

    Science.gov (United States)

    Vachon, David D; Lynam, Donald R; Widiger, Thomas A; Miller, Joshua D; McCrae, Robert R; Costa, Paul T

    2013-05-01

    Personality disorders (PDs) may be better understood in terms of dimensions of general personality functioning rather than as discrete categorical conditions. Personality-trait descriptions of PDs are robust across methods and settings, and PD assessments based on trait measures show good construct validity. The study reported here extends research showing that basic traits (e.g., impulsiveness, warmth, straightforwardness, modesty, and deliberation) can re-create the epidemiological characteristics associated with PDs. Specifically, we used normative changes in absolute trait levels to simulate age-related differences in the prevalence of psychopathy in a forensic setting. Results demonstrated that trait information predicts the rate of decline for psychopathy over the life span; discriminates the decline of psychopathy from that of a similar disorder, antisocial PD; and accurately predicts the differential decline of subfactors of psychopathy. These findings suggest that basic traits provide a parsimonious account of PD prevalence across the life span.

  6. Probabilistic Fatigue Life Prediction of Bridge Cables Based on Multiscaling and Mesoscopic Fracture Mechanics

    Directory of Open Access Journals (Sweden)

    Zhongxiang Liu

    2016-04-01

    Full Text Available Fatigue fracture of bridge stay-cables is usually a multiscale process as the crack grows from micro-scale to macro-scale. Such a process, however, is highly uncertain. In order to make a rational prediction of the residual life of bridge cables, a probabilistic fatigue approach is proposed, based on a comprehensive vehicle load model, finite element analysis and multiscaling and mesoscopic fracture mechanics. Uncertainties in both material properties and external loads are considered. The proposed method is demonstrated through the fatigue life prediction of cables of the Runyang Cable-Stayed Bridge in China, and it is found that cables along the bridge spans may have significantly different fatigue lives, and due to the variability, some of them may have shorter lives than those as expected from the design.

  7. Remaining useful life prediction for an adaptive skew-Wiener process model

    Science.gov (United States)

    Huang, Zeyi; Xu, Zhengguo; Ke, Xiaojie; Wang, Wenhai; Sun, Youxian

    2017-03-01

    Predicting the remaining useful life for operational devices plays a critical role in prognostics and health management. As the models based on the stochastic processes are widely used for characterizing the degradation trajectory, an adaptive skew-Wiener model, which is much more flexible than traditional stochastic process models, is proposed to model the degradation drift of industrial devices. To make full use of the prior knowledge and the historical information, an on-line filtering algorithm is proposed for state estimation, a two-stage algorithm is adopted to estimate unknown parameters as well. For remaining useful life prediction, a novel result is presented with an explicit form based on the closed skew normal distribution. Finally, sufficient Monte Carlo simulations and an application for ball bearings in rotating electrical machines are used to validate our approach.

  8. Physics-based estimates of maximum magnitude of induced earthquakes

    Science.gov (United States)

    Ampuero, Jean-Paul; Galis, Martin; Mai, P. Martin

    2016-04-01

    In this study, we present new findings when integrating earthquake physics and rupture dynamics into estimates of maximum magnitude of induced seismicity (Mmax). Existing empirical relations for Mmax lack a physics-based relation between earthquake size and the characteristics of the triggering stress perturbation. To fill this gap, we extend our recent work on the nucleation and arrest of dynamic ruptures derived from fracture mechanics theory. There, we derived theoretical relations between the area and overstress of overstressed asperity and the ability of ruptures to either stop spontaneously (sub-critical ruptures) or runaway (super-critical ruptures). These relations were verified by comparison with simulation and laboratory results, namely 3D dynamic rupture simulations on faults governed by slip-weakening friction, and laboratory experiments of frictional sliding nucleated by localized stresses. Here, we apply and extend these results to situations that are representative for the induced seismicity environment. We present physics-based predictions of Mmax on a fault intersecting cylindrical reservoir. We investigate Mmax dependence on pore-pressure variations (by varying reservoir parameters), frictional parameters and stress conditions of the fault. We also derive Mmax as a function of injected volume. Our approach provides results that are consistent with observations but suggests different scaling with injected volume than that of empirical relation by McGarr, 2014.

  9. Remaining Useful Life Prediction for Lithium-Ion Batteries Based on Gaussian Processes Mixture

    Science.gov (United States)

    Li, Lingling; Wang, Pengchong; Chao, Kuei-Hsiang; Zhou, Yatong; Xie, Yang

    2016-01-01

    The remaining useful life (RUL) prediction of Lithium-ion batteries is closely related to the capacity degeneration trajectories. Due to the self-charging and the capacity regeneration, the trajectories have the property of multimodality. Traditional prediction models such as the support vector machines (SVM) or the Gaussian Process regression (GPR) cannot accurately characterize this multimodality. This paper proposes a novel RUL prediction method based on the Gaussian Process Mixture (GPM). It can process multimodality by fitting different segments of trajectories with different GPR models separately, such that the tiny differences among these segments can be revealed. The method is demonstrated to be effective for prediction by the excellent predictive result of the experiments on the two commercial and chargeable Type 1850 Lithium-ion batteries, provided by NASA. The performance comparison among the models illustrates that the GPM is more accurate than the SVM and the GPR. In addition, GPM can yield the predictive confidence interval, which makes the prediction more reliable than that of traditional models. PMID:27632176

  10. Anisotropic Elastoplastic Damage Mechanics Method to Predict Fatigue Life of the Structure

    OpenAIRE

    Hualiang Wan; Qizhi Wang; Zheng Zhang

    2016-01-01

    New damage mechanics method is proposed to predict the low-cycle fatigue life of metallic structures under multiaxial loading. The microstructure mechanical model is proposed to simulate anisotropic elastoplastic damage evolution. As the micromodel depends on few material parameters, the present method is very concise and suitable for engineering application. The material parameters in damage evolution equation are determined by fatigue experimental data of standard specimens. By employing fu...

  11. Creep Rupture Life Prediction Based on Analysis of Large Creep Deformation

    OpenAIRE

    YE Wenming; HU Xuteng; Ma, Xiaojian; SONG Yingdong

    2016-01-01

    A creep rupture life prediction method for high temperature component was proposed. The method was based on a true stress-strain elastoplastic creep constitutive model and the large deformation finite element analysis method. This method firstly used the high-temperature tensile stress-strain curve expressed by true stress and strain and the creep curve to build materials' elastoplastic and creep constitutive model respectively, then used the large deformation finite element method to calcula...

  12. Predicting the creep life and failure mode of low-alloy steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Brear, J.M.; Middleton, C.J.; Aplin, P.F. [ERA Technology Ltd., Leatherhead (United Kingdom)

    1998-12-31

    This presentation reviews and consolidates experience gained through a number of research projects and practical plant assessments in predicting both the life and the likely failure mode and location in low alloy steel weldments. The approach adopted begins with the recognition that the relative strength difference between the microstructural regions is a key factor controlling both life and failure location. Practical methods based on hardness measurement and adaptable to differing weld geometries are presented and evidence for correlations between hardness ratio, damage accumulation and strain development is discussed. Predictor diagrams relating weld life and failure location to the service conditions and the hardness of the individual microstructural constituents are suggested and comments are given on the implications for identifying the circumstances in which Type IV cracking is to be expected. (orig.) 6 refs.

  13. Predicting the Reliability of Ceramics Under Transient Loads and Temperatures With CARES/Life

    Science.gov (United States)

    Nemeth, Noel N.; Jadaan, Osama M.; Palfi, Tamas; Baker, Eric H.

    2003-01-01

    A methodology is shown for predicting the time-dependent reliability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The methodology takes into account the changes in material response that can occur with temperature or time (i.e., changing fatigue and Weibull parameters with temperature or time). This capability has been added to the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. The code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.

  14. [A predictive model for the quality of sexual life in hysterectomized women].

    Science.gov (United States)

    Urrutia, María Teresa; Araya, Alejandra; Rivera, Soledad; Viviani, Paola; Villarroel, Luis

    2007-03-01

    The effects of hysterectomy on sexuality has been extensively studied. To establish a model to predict the quality of sexual life in hysterectomized women, six months after surgery. Analytical, longitudinal and prospective study of 90 hysterectomized women aged 45+/-7 years. Two structured interviews at the time of surgery and six months later were carried out to determine the characteristics of sexuality and communication within the couple. In the two interviews, communication and the quality of sexual life were described as "good" in 72 and 77% of women, respectively (NS). The variables that had a 40% influence on the quality of sexual life sixth months after surgery, were oophorectomy status, the presence of orgasm, the characteristics of communication and the basal sexuality with the couple. The sexuality of the hysterectomized women will depend, on a great extent, of pre-surgical variables. Therefore, it is important to consider these variables for the education of hysterectomized women.

  15. Physically based rendering from theory to implementation

    CERN Document Server

    Pharr, Matt

    2010-01-01

    "Physically Based Rendering, 2nd Edition" describes both the mathematical theory behind a modern photorealistic rendering system as well as its practical implementation. A method - known as 'literate programming'- combines human-readable documentation and source code into a single reference that is specifically designed to aid comprehension. The result is a stunning achievement in graphics education. Through the ideas and software in this book, you will learn to design and employ a full-featured rendering system for creating stunning imagery. This book features new sections on subsurface scattering, Metropolis light transport, precomputed light transport, multispectral rendering, and much more. It includes a companion site complete with source code for the rendering system described in the book, with support for Windows, OS X, and Linux. Code and text are tightly woven together through a unique indexing feature that lists each function, variable, and method on the page that they are first described.

  16. An Integrated Approach to Fatigue Life Prediction of Whole System for Offshore Platforms

    Institute of Scientific and Technical Information of China (English)

    方华灿; 段梦兰; 许发彦; 吴永宁; 樊晓东

    2001-01-01

    The failure of one or even more components usually does not lead to the collapse of the whole structure. Most of theanalysis of fatigue is centered on only a single component which the researchers are interested in or much attentionshould be paid to. However, the collapse of a structure is the result of failure of a series of components in a specific orderor path. This paper proposes an integrated approach to fatigue life prediction of whole structural system for offshoreplatforms, mainly describing the basic principles and prediction method. A method is presented for determining the fail-ure path of the whole structure system and calculating the fatigue life in the determined failure path. The correspondingfinal collapse criteria for the whole structure system are discussed. A simple method of equivalent fatigue stress range cal-culation and a mathematical model of structural component fatigue life estimation in consideration of sea wave and seaice loads are provided. As an application of the proposed approach, a fixed production platform Bohai No. 8 is chosenfor the predication of fatigue life of the whole structure system by means of the software OSFAC developed based on thepresent methods.

  17. How do Major, Violent and Nonviolent Opposition Campaigns, Impact Predicted Life Expectancy at birth?

    Directory of Open Access Journals (Sweden)

    Judith Stoddard

    2013-08-01

    Full Text Available This study compared the effects of major violent and nonviolent opposition campaigns for regime change, on predicted life expectancy at birth. The study measured life expectancy five and ten years after the campaign ended, so that deaths which occurred during the campaign would not be included in the metric, and thus enabling the study of changes made in the state on the social determinants affecting longevity, after the campaign was over. Life expectancy is one of the best reported World Development Indicators and is considered to be a good indication of the overall health and general living conditions of the state and therefore is an ideal indicator to reflect the changes made in the state following a major campaign. The results of this analysis showed that states have a hard time recovering from a major opposition campaign and initially drop behind the growth trend in the world average for predicted life expectancy at birth. But, the type of campaign that was waged and whether it was successful, greatly affects the state’s ability to recover. Encouragingly by a decade after the campaign ends, states that experienced a nonviolent campaign that was successful had caught up to the world average and inched ahead of it. This shows that on this important development indicator, new governments that were ushered into power by nonviolent social movements, had made positive changes in the state that enabled it to surpass world averages.

  18. A Modelling Study for Predicting Life of Downhole Tubes Considering Service Environmental Parameters and Stress

    Directory of Open Access Journals (Sweden)

    Tianliang Zhao

    2016-09-01

    Full Text Available A modelling effort was made to try to predict the life of downhole tubes or casings, synthetically considering the effect of service influencing factors on corrosion rate. Based on the discussed corrosion mechanism and corrosion processes of downhole tubes, a mathematic model was established. For downhole tubes, the influencing factors are environmental parameters and stress, which vary with service duration. Stress and the environmental parameters including water content, partial pressure of H2S and CO2, pH value, total pressure and temperature, were considered to be time-dependent. Based on the model, life-span of an L80 downhole tube in oilfield Halfaya, an oilfield in Iraq, was predicted. The results show that life-span of the L80 downhole tube in Halfaya is 247 months (approximately 20 years under initial stress of 0.1 yield strength and 641 months (approximately 53 years under no initial stress, which indicates that an initial stress of 0.1 yield strength will reduce the life-span by more than half.

  19. A New Energy-Critical Plane Damage Parameter for Multiaxial Fatigue Life Prediction of Turbine Blades

    Directory of Open Access Journals (Sweden)

    Zheng-Yong Yu

    2017-05-01

    Full Text Available As one of fracture critical components of an aircraft engine, accurate life prediction of a turbine blade to disk attachment is significant for ensuring the engine structural integrity and reliability. Fatigue failure of a turbine blade is often caused under multiaxial cyclic loadings at high temperatures. In this paper, considering different failure types, a new energy-critical plane damage parameter is proposed for multiaxial fatigue life prediction, and no extra fitted material constants will be needed for practical applications. Moreover, three multiaxial models with maximum damage parameters on the critical plane are evaluated under tension-compression and tension-torsion loadings. Experimental data of GH4169 under proportional and non-proportional fatigue loadings and a case study of a turbine disk-blade contact system are introduced for model validation. Results show that model predictions by Wang-Brown (WB and Fatemi-Socie (FS models with maximum damage parameters are conservative and acceptable. For the turbine disk-blade contact system, both of the proposed damage parameters and Smith-Watson-Topper (SWT model show reasonably acceptable correlations with its field number of flight cycles. However, life estimations of the turbine blade reveal that the definition of the maximum damage parameter is not reasonable for the WB model but effective for both the FS and SWT models.

  20. Life-history traits predict perennial species response to fire in a desert ecosystem

    Science.gov (United States)

    Shryock, Daniel F.; DeFalco, Lesley A.; Esque, Todd C.

    2014-01-01

    The Mojave Desert of North America has become fire-prone in recent decades due to invasive annual grasses that fuel wildfires following years of high rainfall. Perennial species are poorly adapted to fire in this system, and post-fire shifts in species composition have been substantial but variable across community types. To generalize across a range of conditions, we investigated whether simple life-history traits could predict how species responded to fire. Further, we classified species into plant functional types (PFTs) based on combinations of life-history traits and evaluated whether these groups exhibited a consistent fire-response. Six life-history traits varied significantly between burned and unburned areas in short (up to 4 years) or long-term (up to 52 years) post-fire datasets, including growth form, lifespan, seed size, seed dispersal, height, and leaf longevity. Forbs and grasses consistently increased in abundance after fire, while cacti were reduced and woody species exhibited a variable response. Woody species were classified into three PFTs based on combinations of life-history traits. Species in Group 1 increased in abundance after fire and were characterized by short lifespans, small, wind-dispersed seeds, low height, and deciduous leaves. Species in Group 2 were reduced by fire and distinguished from Group 1 by longer lifespans and evergreen leaves. Group 3 species, which also decreased after fire, were characterized by long lifespans, large non-wind dispersed seeds, and taller heights. Our results show that PFTs based on life-history traits can reliably predict the responses of most species to fire in the Mojave Desert. Dominant, long-lived species of this region possess a combination of traits limiting their ability to recover, presenting a clear example of how a novel disturbance regime may shift selective environmental pressures to favor alternative life-history strategies.

  1. Evaluating performance of simplified physically based models for shallow landslide susceptibility

    Science.gov (United States)

    Formetta, Giuseppe; Capparelli, Giovanna; Versace, Pasquale

    2016-11-01

    Rainfall-induced shallow landslides can lead to loss of life and significant damage to private and public properties, transportation systems, etc. Predicting locations that might be susceptible to shallow landslides is a complex task and involves many disciplines: hydrology, geotechnical science, geology, hydrogeology, geomorphology, and statistics. Two main approaches are commonly used: statistical or physically based models. Reliable model applications involve automatic parameter calibration, objective quantification of the quality of susceptibility maps, and model sensitivity analyses. This paper presents a methodology to systemically and objectively calibrate, verify, and compare different models and model performance indicators in order to identify and select the models whose behavior is the most reliable for particular case studies.The procedure was implemented in a package of models for landslide susceptibility analysis and integrated in the NewAge-JGrass hydrological model. The package includes three simplified physically based models for landslide susceptibility analysis (M1, M2, and M3) and a component for model verification. It computes eight goodness-of-fit indices by comparing pixel-by-pixel model results and measurement data. The integration of the package in NewAge-JGrass uses other components, such as geographic information system tools, to manage input-output processes, and automatic calibration algorithms to estimate model parameters. The system was applied for a case study in Calabria (Italy) along the Salerno-Reggio Calabria highway, between Cosenza and Altilia. The area is extensively subject to rainfall-induced shallow landslides mainly because of its complex geology and climatology. The analysis was carried out considering all the combinations of the eight optimized indices and the three models. Parameter calibration, verification, and model performance assessment were performed by a comparison with a detailed landslide inventory map for the

  2. 四参数疲劳定寿方法%Four-parameter life prediction method

    Institute of Scientific and Technical Information of China (English)

    宁向荣; 陈伟; 蔡显新; 廖学军; 米栋

    2012-01-01

    对直升机传动系统采用的一种疲劳定寿方法——四参数法进行了研究:首先介绍了四参数应力一循环(S—N)曲线,然后详细介绍了通过材料平均S—N曲线获取构件安全S—N曲线的步骤以及直升机传动系统四参数疲劳定寿的程序和方法,研究了定寿流程中的各个技术细节.同时介绍了传动系统机匣疲劳试验中的多路协调加载技术以及某传动系统尾减机匣(TGB)的全尺寸疲劳试验情况.最后采用四参数疲劳定寿方法,根据某传动系统尾减机匣全尺寸疲劳试验结果和飞行实测载荷谱,对尾减机匣进行了安全寿命评估.该实例分析表明:四参数疲劳定寿方法为一种有效、可靠的寿命评估方法,具有推广价值.%Four-parameter life prediction method for helicopter transmission system was studied. Four-parameter stress-number of cycles (S-N) curve was presented first, and then, the derivation of helicopter transmission component safe S-N curve from material mean S-N curve and the scheme for the component life prediction were introduced in detail. Multi-load coordinating loading technology in fatigue test and a tail gear box (TGB) casing full-scale fatigue test were introduced at the same time. Finally, according to the full-scale fatigue test result and flight load survey data, applying the four-parameter life prediction method, the TGB casing life prediction was performed, which indicates that four-parameter life prediction method is a reliable and effective method and is worth to be generalized.

  3. Do Personality Traits Predict Functional Impairment and Quality of Life in Adult ADHD? A Controlled Study.

    Science.gov (United States)

    He, J Allison; Antshel, Kevin M; Biederman, Joseph; Faraone, Stephen V

    2015-11-25

    To examine the association of personality traits and characteristics on quality of life and functioning in adults with ADHD. Participants were adults with (n = 206) and without ADHD (n = 123) who completed the Temperament and Character Inventory (TCI), the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), and the Social Adjustment Scale-Self-Report (SAS-SR). Participants also provided information on academic, motor vehicle operation, legal, social, familial, and occupational functioning. Outcomes were examined using stepwise linear regression, logistic regression (for binary outcomes), and negative binomial regression (for count outcomes) controlling for ADHD symptoms, psychiatric comorbidity, and executive dysfunction. Adults with ADHD significantly differed from controls across nearly all TCI personality domains. On average, adults with ADHD endorsed more novelty seeking, harm avoidance, and self-transcendence, and less reward dependence, persistence, self-directedness, and cooperativeness. Personality traits and characteristics, especially self-directedness, significantly predicted functional impairments even after controlling for ADHD symptoms, executive function deficits, and current psychiatric comorbidities. In adults with ADHD, personality traits exert unique associations on quality of life and functional impairment across major life domains, beyond the relations expected of and associated with ADHD symptoms and other associated psychiatric conditions and cognitive vulnerabilities. Addressing personality traits in adults with ADHD may lead to improvements in quality of life and reductions in functional impairment. © The Author(s) 2015.

  4. The Role of Religious Coping in Predicting Quality of Life in Patients with Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    N Askari

    2014-08-01

    Full Text Available Background & aim: Multiple sclerosis is a chronic disease of the nervous system which usually begins in young adults and pathologically characterized by demyelination and glial scarring. According to psychological problems after suffering, the aim of this study was to investigate the influence of religious coping on quality of life in patients with MS. Methods: In the present descriptive study, forty-three patients with multiple sclerosis referred to the CNS Center of Ali bin Abi Talib Hospital of Zahedan, Iran, in 2013 were selected. Using religious coping and quality of life, variables were assessed. The data were analyzed by using the correlation and step-wise regression methods. Results: A positive correlation were seen between religious coping with the passive role due to emotional problems (of QOL and between religious activities and democratic assessments a significant (p<0.05. The regression results also showed that religious activities in the first step alone 0.07 changed the psychological quality of life and in the second step religious activity along with passive religious coping predicted 0.2 of changes of psychological quality of life. Conclusion: Increasing religious and spiritual activities may contribute to improving the quality of life in patients with multiple sclerosis.

  5. Predicting Life-History Trade-Offs with Whole-Organism Performance.

    Science.gov (United States)

    Lailvaux, Simon P; Husak, Jerry F

    2017-08-01

    Whole-organism performance traits are key intermediaries between the organism and the environment. Because performance traits are energetically costly to both build and maintain, performance will compete with other life-history traits over a limited pool of acquired energetic resources at any given time, potentially leading to trade-offs in performance expression. Although these trade-offs can have important implications for organismal fitness we currently lack a conceptual framework for predicting both where trade-offs might be expected, and which traits may be especially prone to trade-offs with other fitness-related life-history traits. We propose such a framework based on an estimate of the energetic requirements of locomotion in vertebrates, the ecological cost of transport. By analyzing existing data on mammalian energetic budgets and life-history, we found that species with higher costs of locomotion also tended to be those with "slow" life histories that invest relatively less in current reproduction than "fast" life-history species. We discuss the potential implications of ectothermy for masking such relationships, and how this framework might be expanded upon in the future. © The Author 2017. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  6. Real time remaining useful life prediction based on nonlinear Wiener based degradation processes with measurement errors

    Institute of Scientific and Technical Information of China (English)

    唐圣金; 郭晓松; 于传强; 周志杰; 周召发; 张邦成

    2014-01-01

    Real time remaining useful life (RUL) prediction based on condition monitoring is an essential part in condition based maintenance (CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item’s individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction.

  7. Prediction Model for the Life of Nickel-cadmium Batteries in Geosynchronous Orbit Satellites

    Science.gov (United States)

    Engleman, J. H.; Zirkes-Falco, M. B.; Bogner, R. S.; Pickett, D. F., Jr.

    1984-01-01

    A mathematical model is described which predicts the service life of nickel-cadmium batteries designed for geosynchronous orbit satellites. Regression analysis technique is used to analyze orbital data on second generation trickle charged batteries. The model gives average cell voltage as a function of design parameters, operating parameters and time. The voltage model has the properties of providing a good fit to the data, good predictive capability, and agreement with known battery performance characteristics. Average cell voltage can be predicted to within 0.02 volts for up to 8 years. This modeling shows that these batteries will operate reliably for 10 years. Third-generation batteries are expected to operate even longer.

  8. Prediction of Combine Economic Life Based on Repair and Maintenance Costs Model

    Directory of Open Access Journals (Sweden)

    A Rohani

    2014-09-01

    Full Text Available Farm machinery managers often need to make complex economic decisions on machinery replacement. Repair and maintenance costs can have significant impacts on this economic decision. The farm manager must be able to predict farm machinery repair and maintenance costs. This study aimed to identify a regression model that can adequately represent the repair and maintenance costs in terms of machine age in cumulative hours of use. The regression model has the ability to predict the repair and maintenance costs for longer time periods. Therefore, it can be used for the estimation of the economic life. The study was conducted using field data collected from 11 John-Deer 955 combine harvesters used in several western provinces of Iran. It was found that power model has a better performance for the prediction of combine repair and maintenance costs. The results showed that the optimum replacement age of John-Deer 955 combine was 54300 cumulative hours.

  9. Toward Inverse Control of Physics-Based Sound Synthesis

    Science.gov (United States)

    Pfalz, A.; Berdahl, E.

    2017-05-01

    Long Short-Term Memory networks (LSTMs) can be trained to realize inverse control of physics-based sound synthesizers. Physics-based sound synthesizers simulate the laws of physics to produce output sound according to input gesture signals. When a user's gestures are measured in real time, she or he can use them to control physics-based sound synthesizers, thereby creating simulated virtual instruments. An intriguing question is how to program a computer to learn to play such physics-based models. This work demonstrates that LSTMs can be trained to accomplish this inverse control task with four physics-based sound synthesizers.

  10. A novel health indicator for on-line lithium-ion batteries remaining useful life prediction

    Science.gov (United States)

    Zhou, Yapeng; Huang, Miaohua; Chen, Yupu; Tao, Ye

    2016-07-01

    Prediction of lithium-ion batteries remaining useful life (RUL) plays an important role in an intelligent battery management system. The capacity and internal resistance are often used as the batteries health indicator (HI) for quantifying degradation and predicting RUL. However, on-line measurement of capacity and internal resistance are hardly realizable due to the not fully charged and discharged condition and the extremely expensive cost, respectively. Therefore, there is a great need to find an optional way to deal with this plight. In this work, a novel HI is extracted from the operating parameters of lithium-ion batteries for degradation modeling and RUL prediction. Moreover, Box-Cox transformation is employed to improve HI performance. Then Pearson and Spearman correlation analyses are utilized to evaluate the similarity between real capacity and the estimated capacity derived from the HI. Next, both simple statistical regression technique and optimized relevance vector machine are employed to predict the RUL based on the presented HI. The correlation analyses and prediction results show the efficiency and effectiveness of the proposed HI for battery degradation modeling and RUL prediction.

  11. Flexural fatigue life prediction of closed hat-section using materially nonlinear axial fatigue characteristics

    Science.gov (United States)

    Razzaq, Zia

    1989-01-01

    Straight or curved hat-section members are often used as structural stiffeners in aircraft. For instance, they are employed as stiffeners for the dorsal skin as well as in the aerial refueling adjacent area structure in F-106 aircraft. The flanges of the hat-section are connected to the aircraft skin. Thus, the portion of the skin closing the hat-section interacts with the section itself when resisting the stresses due to service loads. The flexural fatigue life of such a closed section is estimated using materially nonlinear axial fatigue characteristics. It should be recognized that when a structural shape is subjected to bending, the fatigue life at the neutral axis is infinity since the normal stresses are zero at that location. Conversely, the fatigue life at the extreme fibers where the normal bending stresses are maximum can be expected to be finite. Thus, different fatigue life estimates can be visualized at various distances from the neural axis. The problem becomes compounded further when significant portions away from the neutral axis are stressed into plastic range. A theoretical analysis of the closed hat-section subjected to flexural cyclic loading is first conducted. The axial fatigue characteristics together with the related axial fatigue life formula and its inverted form given by Manson and Muralidharan are adopted for an aluminum alloy used in aircraft construction. A closed-form expression for predicting the flexural fatigue life is then derived for the closed hat-section including materially nonlinear action. A computer program is written to conduct a study of the variables such as the thicknesses of the hat-section and the skin, and the type of alloy used. The study has provided a fundamental understanding of the flexural fatigue life characteristics of a practical structural component used in aircraft when materially nonlinear action is present.

  12. A physically-based abrasive wear model for composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  13. Application of Physically based landslide susceptibility models in Brazil

    Science.gov (United States)

    Carvalho Vieira, Bianca; Martins, Tiago D.

    2017-04-01

    Shallow landslides and floods are the processes responsible for most material and environmental damages in Brazil. In the last decades, some landslides events induce a high number of deaths (e.g. Over 1000 deaths in one event) and incalculable social and economic losses. Therefore, the prediction of those processes is considered an important tool for land use planning tools. Among different methods the physically based landslide susceptibility models having been widely used in many countries, but in Brazil it is still incipient when compared to other ones, like statistical tools and frequency analyses. Thus, the main objective of this research was to assess the application of some Physically based landslide susceptibility models in Brazil, identifying their main results, the efficiency of susceptibility mapping, parameters used and limitations of the tropical humid environment. In order to achieve that, it was evaluated SHALSTAB, SINMAP and TRIGRS models in some studies in Brazil along with the Geotechnical values, scales, DEM grid resolution and the results based on the analysis of the agreement between predicted susceptibility and the landslide scar's map. Most of the studies in Brazil applied SHALSTAB, SINMAP and to a lesser extent the TRIGRS model. The majority researches are concentrated in the Serra do Mar mountain range, that is a system of escarpments and rugged mountains that extends more than 1,500 km along the southern and southeastern Brazilian coast, and regularly affected by heavy rainfall that generates widespread mass movements. Most part of these studies used conventional topographic maps with scales ranging from 1:2000 to 1:50000 and DEM-grid resolution between 2 and 20m. Regarding the Geotechnical and hydrological values, a few studies use field collected data which could produce more efficient results, as indicated by international literature. Therefore, even though they have enormous potential in the susceptibility mapping, even for comparison

  14. Leaf and life history traits predict plant growth in a green roof ecosystem.

    Science.gov (United States)

    Lundholm, Jeremy; Heim, Amy; Tran, Stephanie; Smith, Tyler

    2014-01-01

    Green roof ecosystems are constructed to provide services such as stormwater retention and urban temperature reductions. Green roofs with shallow growing media represent stressful conditions for plant survival, thus plants that survive and grow are important for maximizing economic and ecological benefits. While field trials are essential for selecting appropriate green roof plants, we wanted to determine whether plant leaf traits could predict changes in abundance (growth) to provide a more general framework for plant selection. We quantified leaf traits and derived life-history traits (Grime's C-S-R strategies) for 13 species used in a four-year green roof experiment involving five plant life forms. Changes in canopy density in monocultures and mixtures containing one to five life forms were determined and related to plant traits using multiple regression. We expected traits related to stress-tolerance would characterize the species that best grew in this relatively harsh setting. While all species survived to the end of the experiment, canopy species diversity in mixture treatments was usually much lower than originally planted. Most species grew slower in mixture compared to monoculture, suggesting that interspecific competition reduced canopy diversity. Species dominant in mixture treatments tended to be fast-growing ruderals and included both native and non-native species. Specific leaf area was a consistently strong predictor of final biomass and the change in abundance in both monoculture and mixture treatments. Some species in contrasting life-form groups showed compensatory dynamics, suggesting that life-form mixtures can maximize resilience of cover and biomass in the face of environmental fluctuations. This study confirms that plant traits can be used to predict growth performance in green roof ecosystems. While rapid canopy growth is desirable for green roofs, maintenance of species diversity may require engineering of conditions that favor less

  15. Leaf and life history traits predict plant growth in a green roof ecosystem.

    Directory of Open Access Journals (Sweden)

    Jeremy Lundholm

    Full Text Available Green roof ecosystems are constructed to provide services such as stormwater retention and urban temperature reductions. Green roofs with shallow growing media represent stressful conditions for plant survival, thus plants that survive and grow are important for maximizing economic and ecological benefits. While field trials are essential for selecting appropriate green roof plants, we wanted to determine whether plant leaf traits could predict changes in abundance (growth to provide a more general framework for plant selection. We quantified leaf traits and derived life-history traits (Grime's C-S-R strategies for 13 species used in a four-year green roof experiment involving five plant life forms. Changes in canopy density in monocultures and mixtures containing one to five life forms were determined and related to plant traits using multiple regression. We expected traits related to stress-tolerance would characterize the species that best grew in this relatively harsh setting. While all species survived to the end of the experiment, canopy species diversity in mixture treatments was usually much lower than originally planted. Most species grew slower in mixture compared to monoculture, suggesting that interspecific competition reduced canopy diversity. Species dominant in mixture treatments tended to be fast-growing ruderals and included both native and non-native species. Specific leaf area was a consistently strong predictor of final biomass and the change in abundance in both monoculture and mixture treatments. Some species in contrasting life-form groups showed compensatory dynamics, suggesting that life-form mixtures can maximize resilience of cover and biomass in the face of environmental fluctuations. This study confirms that plant traits can be used to predict growth performance in green roof ecosystems. While rapid canopy growth is desirable for green roofs, maintenance of species diversity may require engineering of conditions that

  16. Predicting life satisfaction during middle adulthood from peer relationships during mid-adolescence.

    Science.gov (United States)

    Marion, Donna; Laursen, Brett; Zettergren, Peter; Bergman, Lars R

    2013-08-01

    The immediate advantages of adolescent friendships and disadvantages of peer rejection are well documented, but there is little evidence that these effects extend into adulthood. This study tested the hypothesis that peer relationships during adolescence predict life satisfaction during middle adulthood, using data from a 30-year prospective longitudinal study. Participants included 996 (49.5% female) 8th grade students from a community sample of Swedish youth. Self-reports of friendship and peer reports of rejection were obtained when participants were age 15. Self-reports of global life satisfaction and perceived relationship quality were collected at age 43 for women and age 48 for men. Path analyses tested a direct-effects model that examined links from adolescent friendship participation and peer rejection to middle adulthood outcomes, and a buffered-effects model that examined links from adolescent peer rejection to middle adulthood outcomes, separately for those with and without friends during adolescence. Strong support emerged for the buffered-effects model but not the direct-effects model. Adolescent friendship participation moderated associations between adolescent peer rejection and adult global life satisfaction and between adolescent peer rejection and adult perceived relationship quality such that peer rejection predicted poorer adult outcomes for youth without friends but not for youth with friends. The findings suggest that the risks of peer rejection-and benefits of friendship-extend from adolescence well into middle age.

  17. Fatigue life prediction method for contact wire using maximum local stress

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Seok; Haochuang, Li; Seok, Chang Sung; Koo, Jae Mean [Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Ki Won; Kwon, Sam Young; Cho, Yong Hyeon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2015-01-15

    Railway contact wires supplying electricity to trains are exposed to repeated mechanical strain and stress caused by their own weight and discontinuous contact with a pantograph during train operation. Since the speed of railway transportation has increased continuously, railway industries have recently reported a number of contact wire failures caused by mechanical fatigue fractures instead of normal wear, which has been a more common failure mechanism. To secure the safety and durability of contact wires in environments with increased train speeds, a bending fatigue test on contact wire has been performed. The test equipment is too complicated to evaluate the fatigue characteristics of contact wire. Thus, the axial tension fatigue test was performed for a standard specimen, and the bending fatigue life for the contact wire structure was then predicted using the maximum local stress occurring at the top of the contact wire. Lastly, the tested bending fatigue life of the structure was compared with the fatigue life predicted by the axial tension fatigue test for verification.

  18. Fatigue Life Prediction of Multi Leaf Spring used in the Suspension System of Light Commercial Vehicle

    Directory of Open Access Journals (Sweden)

    V.K.Aher

    2012-06-01

    Full Text Available The Leaf spring is widely used in automobiles and one of the components of suspension system. It needs to have high fatigue life. As a general rule, the leaf spring is regarded as a safety component as failure could lead to severe accidents. The purpose of this paper is to predict the fatigue life of steel leaf spring along with analytical stress and deflection calculations. This present work describes static and fatigue analysis of a steel leaf spring of a light commercial vehicle (LCV. The dimensions of the leaf spring of a LCV are taken and are verified by design calculations. The non-linear static analysis of 2D model of the leaf spring is performed using NASTRAN solver and compared with analytical results. The preprocessing of the model is done by using HYPERMESH software. The stiffness of the leaf spring is studied by plotting load versus deflection curve for various load applications. The simulation results are compared with analytical results. The fatigue life of the leaf spring is predicted using MSC Fatigue software.

  19. Psychological approach to successful ageing predicts future quality of life in older adults

    Directory of Open Access Journals (Sweden)

    Iliffe Steve

    2011-03-01

    Full Text Available Abstract Background Public policies aim to promote well-being, and ultimately the quality of later life. Positive perspectives of ageing are underpinned by a range of appraoches to successful ageing. This study aimed to investigate whether baseline biological, psychological and social aproaches to successful ageing predicted future QoL. Methods Postal follow-up in 2007/8 of a national random sample of 999 people aged 65 and over in 1999/2000. Of 496 valid addresses of survivors at follow-up, the follow-up response rate was 58% (287. Measures of the different concepts of successful ageing were constructed using baseline indicators. They were assessed for their ability to independently predict quality of life at follow-up. Results Few respondents achieved all good scores within each of the approaches to successful ageing. Each approach was associated with follow-up QoL when their scores were analysed continuously. The biomedical (health approach failed to achieve significance when the traditional dichotomous cut-off point for successfully aged (full health, or not (less than full health, was used. In multiple regression analyses of the relative predictive ability of each approach, only the psychological approach (perceived self-efficacy and optimism retained significance. Conclusion Only the psychological approach to successful ageing independently predicted QoL at follow-up. Successful ageing is not only about the maintenance of health, but about maximising one's psychological resources, namely self-efficacy and resilience. Increasing use of preventive care, better medical management of morbidity, and changing lifestyles in older people may have beneficial effects on health and longevity, but may not improve their QoL. Adding years to life and life to years may require two distinct and different approaches, one physical and the other psychological. Follow-up health status, number of supporters and social activities, and self-rated active ageing

  20. Life prediction of prediction beams of high- pile wharf in service life%在役高桩码头横梁剩余寿命预测

    Institute of Scientific and Technical Information of China (English)

    孟静; 李鑫

    2014-01-01

    This paper starts with the impact resistance of high-pile wharf structure’s changes,including chloride,carbona-tion of concrete, concrete strength and other factors which changed over time, and considers the uncertainty of the material itself. After a comprehensive analysis, the model of beam resistance changes over time was established and taken the cross member reinforced concrete corrosion time as a variable. It calculated the reliability index of high-pile wharf beams,and made a solution combined with the reliability index required by codes to obtain the service life. The results show that meet engineering practice. The research results can provide a scientific basis for life prediction of high-pile wharf structure.%从影响高桩码头结构抗力变化的氯离子、混凝土碳化、混凝土强度等随时间变化的主要因素入手,考虑了材料本身的不确定性。综合分析后,将横梁构件钢筋混凝土锈蚀时间作为变量,建立了横梁抗力随时间变化的模型,计算了该港区的码头横梁可靠指标,并和规范要求的可靠指标联合求解,得出了其使用年限。结果表明符合该工程实际。研究结果可为高桩码头结构寿命预测提供科学的依据。

  1. Comparisons of prediction models of quality of life after laparoscopic cholecystectomy: a longitudinal prospective study.

    Directory of Open Access Journals (Sweden)

    Hon-Yi Shi

    Full Text Available BACKGROUND: Few studies of laparoscopic cholecystectomy (LC outcome have used longitudinal data for more than two years. Moreover, no studies have considered group differences in factors other than outcome such as age and nonsurgical treatment. Additionally, almost all published articles agree that the essential issue of the internal validity (reproducibility of the artificial neural network (ANN, support vector machine (SVM, Gaussian process regression (GPR and multiple linear regression (MLR models has not been adequately addressed. This study proposed to validate the use of these models for predicting quality of life (QOL after LC and to compare the predictive capability of ANNs with that of SVM, GPR and MLR. METHODOLOGY/PRINCIPAL FINDINGS: A total of 400 LC patients completed the SF-36 and the Gastrointestinal Quality of Life Index at baseline and at 2 years postoperatively. The criteria for evaluating the accuracy of the system models were mean square error (MSE and mean absolute percentage error (MAPE. A global sensitivity analysis was also performed to assess the relative significance of input parameters in the system model and to rank the variables in order of importance. Compared to SVM, GPR and MLR models, the ANN model generally had smaller MSE and MAPE values in the training data set and test data set. Most ANN models had MAPE values ranging from 4.20% to 8.60%, and most had high prediction accuracy. The global sensitivity analysis also showed that preoperative functional status was the best parameter for predicting QOL after LC. CONCLUSIONS/SIGNIFICANCE: Compared with SVM, GPR and MLR models, the ANN model in this study was more accurate in predicting patient-reported QOL and had higher overall performance indices. Further studies of this model may consider the effect of a more detailed database that includes complications and clinical examination findings as well as more detailed outcome data.

  2. Predicting employment status and subjective quality of life in patients with schizophrenia

    Directory of Open Access Journals (Sweden)

    Haruo Fujino

    2016-03-01

    Full Text Available Although impaired social functioning, particularly poor employment status, is a cardinal feature of patients with schizophrenia and leads to decreased quality of life (QOL, few studies have addressed the relationship between these two clinical issues. The aim of this study was to determine whether employment status predicts subjective QOL and to evaluate a model in which functional capacity mediates the relationship between general cognitive performance and employment status. Ninety-three patients with schizophrenia were administered a comprehensive battery of cognitive tests, the UCSD Performance-based Skills Assessment-Brief version (UPSA-B, the Social Functioning Scale (SFS, and the Subjective Quality of Life Scale (SQLS. First, we evaluated a model for predicting the employment/occupation subscale score of the SFS using path analysis, and the model fitted well (χ2 (4 = 3.6, p = 0.46; CFI = 1.0; RMSEA < 0.001, with 90% CIs: 0–0.152. Employment status was predicted by negative symptoms and functional capacity, which was in turn predicted by general cognitive performance. Second, we added subjective QOL to this model. In a final path model, QOL was predicted by negative symptoms and employment status. This model also satisfied good fit criteria (χ2 (7 = 10.3, p = 0.17; CFI = 0.987; RMSEA = 0.072, with 90% CIs: 0–0.159. The UPSA-B and SFS scores were moderately correlated with most measures of cognitive performance. These results support the notion that better employment status enhances subjective QOL in patients with schizophrenia.

  3. Incorporation of Half-Cycle Theory Into Ko Aging Theory for Aerostructural Flight-Life Predictions

    Science.gov (United States)

    Ko, William L.; Tran, Van T.; Chen, Tony

    2007-01-01

    The half-cycle crack growth theory was incorporated into the Ko closed-form aging theory to improve accuracy in the predictions of operational flight life of failure-critical aerostructural components. A new crack growth computer program was written for reading the maximum and minimum loads of each half-cycle from the random loading spectra for crack growth calculations and generation of in-flight crack growth curves. The unified theories were then applied to calculate the number of flights (operational life) permitted for B-52B pylon hooks and Pegasus adapter pylon hooks to carry the Hyper-X launching vehicle that air launches the X-43 Hyper-X research vehicle. A crack growth curve for each hook was generated for visual observation of the crack growth behavior during the entire air-launching or captive flight. It was found that taxiing and the takeoff run induced a major portion of the total crack growth per flight. The operational life theory presented can be applied to estimate the service life of any failure-critical structural components.

  4. Neuroticism and Extraversion in Youth Predict Mental Wellbeing and Life Satisfaction 40 Years Later.

    Science.gov (United States)

    Gale, Catharine R; Booth, Tom; Mõttus, René; Kuh, Diana; Deary, Ian J

    2013-12-01

    Neuroticism and Extraversion are linked with current wellbeing, but it is unclear whether these traits in youth predict wellbeing decades later. We applied structural equation modelling to data from 4583 people from the MRC National Survey of Health and Development. We examined the effects of Neuroticism and Extraversion at ages 16 and 26 years on mental wellbeing and life satisfaction at age 60-64 and explored the mediating roles of psychological and physical health. Extraversion had direct, positive effects on both measures of wellbeing. The impact of Neuroticism on both wellbeing and life satisfaction was largely indirect through susceptibility to psychological distress and physical health problems. Personality dispositions in youth have enduring influence on wellbeing assessed about forty years later.

  5. Computational Methodology for the Prediction of Functional Requirement Variations Across the Product Life-Cycle

    CERN Document Server

    Mandil, Guillaume; Rivière, Alain

    2009-01-01

    The great majority of engineered products are subject to thermo-mechanical loads which vary with the product environment during the various phases of its life-cycle (machining, assembly, intended service use...). Those load variations may result in different values of the parts nominal dimensions, which in turn generate corresponding variation of the effective clearance (functional requirement) in the assembly. Usually, and according to the contractual drawings, the parts are measured after the machining stage, whereas the interesting measurement values are the ones taken in service for they allow the prediction of clearance value under operating conditions. Unfortunately, measurement in operating conditions may not be practical to obtain. Hence, the main purpose of this research is to create, through computations and simulations, links between the values of the loads, dimensions and functional requirements during the successive phases of the life cycle of some given product. [...

  6. Mathematical Model of Load Pass and Prediction of Fatigue Life on Bolt Threads with Reduced Lead

    Science.gov (United States)

    Asayama, Yukiteru

    A mathematical model is proposed in order to elucidate the mechanism that the fatigue strength of external threads increases by reducing the lead on a thread system such as a bolt and nut. The model is constructed from the concept that a local strain proportional to the reducing degree of the lead, although the local strain is at first produced in the bolt thread farthest from the bearing surface of the nut, is induced in each thread root with an increase of applied load. The fatigue life predicted from the mathematical model shows good agreement with the experimental fatigue life of cadmium-plated external threads with the reduced lead on the material having strength as high as 1270MPa. The model can provide useful suggestions for the design of fasteners for aerospace, which are required to satisfy severe requirements of fatigue strengths and dimensions.

  7. Structural strength analysis and fatigue life prediction of traction converter box in high-speed EMU

    Science.gov (United States)

    Tan, Qin; Li, Qiang

    2017-01-01

    The method of building the FEA model of traction converter box in high-speed EMU and analyzing the static strength and fatigue strength of traction converter box based on IEC 61373-2010 and EN 12663 standards is presented in this paper. The load-stress correlation coefficients of weak points is obtained by FEA model, applied to transfer the load history of traction converter box to stress history of each point. The fatigue damage is calculated based on Miner's rule and the fatigue life of traction converter box is predicted. According to study, the structural strength of traction converter box meets design requirements.

  8. The Potential United Kingdom Energy Gap and Creep Life Prediction Methodologies

    Science.gov (United States)

    Evans, Mark

    2013-01-01

    The United Kingdom faces a looming energy gap with around 20 pct of its generating capacity due for closure in the next 10 to 15 years as a result of plant age and new European legislation on environmental protection and safety at work. A number of solutions exist for this problem including the use of new materials so that new plants can operate at higher temperatures, new technologies related to carbon capture and gasification, development of renewable resources, and less obviously the use of accurate models for predicting creep life. This article reviews, with illustrations, some of the more applicable and successful creep prediction methodologies used by academics and industrialists and highlights how these techniques can help alleviate the looming energy gap. The role that these approaches can play in solving the energy gap is highlighted throughout.

  9. Artificial Fish Swarm Algorithm-Based Particle Filter for Li-Ion Battery Life Prediction

    Directory of Open Access Journals (Sweden)

    Ye Tian

    2014-01-01

    Full Text Available An intelligent online prognostic approach is proposed for predicting the remaining useful life (RUL of lithium-ion (Li-ion batteries based on artificial fish swarm algorithm (AFSA and particle filter (PF, which is an integrated approach combining model-based method with data-driven method. The parameters, used in the empirical model which is based on the capacity fade trends of Li-ion batteries, are identified dependent on the tracking ability of PF. AFSA-PF aims to improve the performance of the basic PF. By driving the prior particles to the domain with high likelihood, AFSA-PF allows global optimization, prevents particle degeneracy, thereby improving particle distribution and increasing prediction accuracy and algorithm convergence. Data provided by NASA are used to verify this approach and compare it with basic PF and regularized PF. AFSA-PF is shown to be more accurate and precise.

  10. [Prediction of life expectancy for prostate cancer patients based on the kinetic theory of aging of living systems].

    Science.gov (United States)

    Viktorov, A A; Zharinov, G M; Neklasova, N Ju; Morozova, E E

    2017-01-01

    The article presents a methodical approach for prediction of life expectancy for people diagnosed with prostate cancer based on the kinetic theory of aging of living systems. The life expectancy is calculated by solving the differential equation for the rate of aging for three different stage of life - «normal» life, life with prostate cancer and life after combination therapy for prostate cancer. The mathematical model of aging for each stage of life has its own parameters identified by the statistical analysis of healthcare data from the Zharinov's databank and Rosstat CDR NES databank. The core of the methodical approach is the statistical correlation between growth rate of the prostate specific antigen level (PSA-level) or the PSA doubling time (PSA DT) before therapy, and lifespan: the higher the PSA DT is, the greater lifespan. The patients were grouped under the «fast PSA DT» and «slow PSA DT» categories. The satisfactory matching between calculations and experiment is shown. The prediction error of group life expectancy is due to the completeness and reliability of the main data source. A detailed monitoring of the basic health indicators throughout the each person life in each analyzed group is required. The absence of this particular information makes it impossible to predict the individual life expectancy.

  11. Life history trade-off moderates model predictions of diversity loss from climate change.

    Science.gov (United States)

    Moor, Helen

    2017-01-01

    Climate change can trigger species range shifts, local extinctions and changes in diversity. Species interactions and dispersal capacity are important mediators of community responses to climate change. The interaction between multispecies competition and variation in dispersal capacity has recently been shown to exacerbate the effects of climate change on diversity and to increase predictions of extinction risk dramatically. Dispersal capacity, however, is part of a species' overall ecological strategy and are likely to trade off with other aspects of its life history that influence population growth and persistence. In plants, a well-known example is the trade-off between seed mass and seed number. The presence of such a trade-off might buffer the diversity loss predicted by models with random but neutral (i.e. not impacting fitness otherwise) differences in dispersal capacity. Using a trait-based metacommunity model along a warming climatic gradient the effect of three different dispersal scenarios on model predictions of diversity change were compared. Adding random variation in species dispersal capacity caused extinctions by the introduction of strong fitness differences due an inherent property of the dispersal kernel. Simulations including a fitness-equalising trade-off based on empirical relationships between seed mass (here affecting dispersal distance, establishment probability, and seedling biomass) and seed number (fecundity) maintained higher initial species diversity and predicted lower extinction risk and diversity loss during climate change than simulations with variable dispersal capacity. Large seeded species persisted during climate change, but developed lags behind their climate niche that may cause extinction debts. Small seeded species were more extinction-prone during climate change but tracked their niches through dispersal and colonisation, despite competitive resistance from residents. Life history trade-offs involved in coexistence

  12. Adolescent inpatient girls׳ report of dependent life events predicts prospective suicide risk.

    Science.gov (United States)

    Stone, Lindsey B; Liu, Richard T; Yen, Shirley

    2014-09-30

    Adolescents with a history of suicidal behavior are especially vulnerable for future suicide attempts, particularly following discharge from an inpatient psychiatric admission. This study is the first to test whether adolescents׳ tendency to generate stress, or report more dependent events to which they contributed, was predictive of prospective suicide events. Ninety adolescent psychiatric inpatients who were admitted for recent suicide risk, completed diagnostic interviews, assessments of history of suicidal behavior, and a self-report questionnaire of major life events at baseline. Participants were followed over the subsequent 6 months after discharge to assess stability vs. onset of suicide events. Cox proportional hazard regressions were used to predict adolescents׳ time to suicide events. Results supported hypothesis, such that only recent greater dependent events, not independent or overall events, predicted risk for prospective suicide events. This effect was specific to adolescent girls. Importantly, dependent events maintained statistical significance as a predictor of future suicide events after co-varying for the effects of several established risk factors and psychopathology. Results suggest that the tendency to generate dependent events may contribute unique additional prediction for adolescent girls׳ prospective suicide risk, and highlight the need for future work in this area.

  13. Genomic biomarkers of prenatal intrauterine inflammation in umbilical cord tissue predict later life neurological outcomes.

    Science.gov (United States)

    Tilley, Sloane K; Joseph, Robert M; Kuban, Karl C K; Dammann, Olaf U; O'Shea, T Michael; Fry, Rebecca C

    2017-01-01

    Preterm birth is a major risk factor for neurodevelopmental delays and disorders. This study aimed to identify genomic biomarkers of intrauterine inflammation in umbilical cord tissue in preterm neonates that predict cognitive impairment at 10 years of age. Genome-wide messenger RNA (mRNA) levels from umbilical cord tissue were obtained from 43 neonates born before 28 weeks of gestation. Genes that were differentially expressed across four indicators of intrauterine inflammation were identified and their functions examined. Exact logistic regression was used to test whether expression levels in umbilical cord tissue predicted neurocognitive function at 10 years of age. Placental indicators of inflammation were associated with changes in the mRNA expression of 445 genes in umbilical cord tissue. Transcripts with decreased expression showed significant enrichment for biological signaling processes related to neuronal development and growth. The altered expression of six genes was found to predict neurocognitive impairment when children were 10 years old These genes include two that encode for proteins involved in neuronal development. Prenatal intrauterine inflammation is associated with altered gene expression in umbilical cord tissue. A set of six of the differentially expressed genes predict cognitive impairment later in life, suggesting that the fetal environment is associated with significant adverse effects on neurodevelopment that persist into later childhood.

  14. Physics-Based Pneumatic Hammer Instability Model Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Florida Turbine Technologies (FTT) proposes to conduct research necessary to develop a physics-based pneumatic hammer instability model for hydrostatic bearings...

  15. A review on fatigue life prediction methods for anti-vibration rubber materials

    Directory of Open Access Journals (Sweden)

    Xiaoli WANG

    2016-08-01

    Full Text Available Anti-vibration rubber, because of its superior elasticity, plasticity, waterproof and trapping characteristics, is widely used in the automotive industry, national defense, construction and other fields. The theory and technology of predicting fatigue life is of great significance to improve the durability design and manufacturing of anti-vibration rubber products. According to the characteristics of the anti-vibration rubber products in service, the technical difficulties for analyzing fatigue properties of anti-vibration rubber materials are pointed out. The research progress of the fatigue properties of rubber materials is reviewed from three angles including methods of fatigue crack initiation, fatigue crack propagation and fatigue damage accumulation. It is put forward that some nonlinear characteristics of rubber under fatigue loading, including the Mullins effect, permanent deformation and cyclic stress softening, should be considered in the further study of rubber materials. Meanwhile, it is indicated that the fatigue damage accumulation method based on continuum damage mechanics might be more appropriate to solve fatigue damage and life prediction problems for complex rubber materials and structures under fatigue loading.

  16. Lubrication Oil Condition Monitoring and Remaining Useful Life Prediction With Particle Filtering

    Directory of Open Access Journals (Sweden)

    Yongzhi Qu

    2013-01-01

    Full Text Available In order to reduce the costs of wind energy, it is necessary to improve the wind turbine availability and reduce the operational and maintenance costs. The reliability and availability of a functioning wind turbine depend largely on the protective properties of the lubrication oil for its drive train subassemblies such as gearbox and means for lubrication oil condition monitoring and degradation detection. The wind industry currently uses lubrication oil analysis for detecting gearbox and bearing wear but cannot detect the functional failures of the lubrication oils. The main purpose of lubrication oil condition monitoring and degradation detection is to determine whether the oils have deteriorated to such a degree that they no longer fulfill their functions. This paper describes a research on developing online lubrication oil health condition monitoring and remaining useful life prediction with particle filtering technique using commercially available online sensors. The paper first presents a survey on current state-of-the-art online lubrication oil condition monitoring solutions and their characteristics along with the classification and evaluation of each technique. It is then followed by an investigation on wind turbine gearbox lubrication oil health condition monitoring and degradation detection using online viscosity and dielectric constant sensors. In particular, the lubricant performance evaluation and remaining useful life prediction of degraded lubrication oil with viscosity and dielectric constant data using particle filtering are presented. A simulation case study is provided to demonstrate the effectiveness of the developed technique.

  17. Baseline Quality of Life Factors Predict Long Term Survival after Elective Resection for Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Abhiram Sharma

    2013-01-01

    Full Text Available Background. Studies have shown an association between baseline quality of life (Qol and survival in advanced cancers. The aim of this study was to investigate their predictive value in long term survival after elective colorectal cancer resection. Methods. A consecutive series of patients undergoing elective colorectal cancer surgery for nonmetastatic disease were recruited in 2003/04. Patients completed standardized quality of life questionnaires (HADS, FACTC, MRS, and PANAS prior to and 6 weeks after surgery. Univariate (log-rank test and multivariate analyses (Cox proportional hazards were performed to predict long term survival. Results. Ninety-seven patients met the inclusion criteria. Sixty-five (67% were male and the median age of the group was 70 years. Forty-six (47.5% patients had died and the mean survival was 1,741 days (median 2159, range 9–2923 days. Preoperative mood rating scale and functional assessment of cancer therapy-colorectal FACT C emotional well-being and postoperative FACT C additional concerns were independent predictors of long term survival. Conclusion. Incorporating psychosocial measures in preoperative assessment of cancer patients could help to identify patients who require assessment with a view to implementing psychosocial interventions. These active interventions to maximize mood and well-being should form an integral part of multidisciplinary treatment in these patients.

  18. Contact Stress Analysis and Fatigue Life Prediction of a Turbine Fan Disc

    Science.gov (United States)

    Yang, Liang; Zhu, Shun-Peng; Lv, Zhiqiang; Zuo, Fang-Jun; Huang, Hong-Zhong

    2016-06-01

    Fan discs are critical components of an aero engine. In this paper, contact stress and life prediction of a turbine fan disc were investigated. A simplified pin/disc model was conducted to simulate the practical working condition under applied loads using finite element (FE) analysis. This study is devoted to examining the effects of interface condition of pin/disc such as gap and coefficient upon the maximum stress. The FE model indicated that the maximum stress occurs at the top right corner in the second pin hole, and larger gap or friction coefficient has a significant effect on the maximum stress. In addition, FE analysis without considering friction is also conducted. The results show that the dangerous point is similar to the result which considers friction and the stress state is relatively larger than that of considering friction. Finally, based on FE analysis result, life prediction for the fan disc is conducted to combine the material S-N curve, mean stress effects and concentration stress factor obtained by means of FE method.

  19. Service Life Prediction of Wood Claddings by in-situ Measurement of Wood Moisture Content

    DEFF Research Database (Denmark)

    Engelund, Emil Tang; Lindegaard, Berit; Morsing, Niels

    2009-01-01

    The Danish Technological Institute is in co-operation with industry partners running a project aiming at predicting the service life of different wood protecting systems. The project focuses on examining the moisture reducing effect of different protecting systems for timber claddings and the abi......The Danish Technological Institute is in co-operation with industry partners running a project aiming at predicting the service life of different wood protecting systems. The project focuses on examining the moisture reducing effect of different protecting systems for timber claddings...... are exposed. This study examines the data from the first five years of outdoor exposure using data from a test rack with a water-borne acrylic coating and a test rack with ICP coating for case studies. The moisture content data was converted into weekly average and weekly variation values which gave a deeper...... insight into the performance of the tested systems. The first was used to check for moisture build-up in the construction whereas the latter gave an indication of the gradual degradation of the coating itself, i.e. the degree of cracking. A linear tendency with time was found for all tested systems...

  20. Attachment style predicts affect, cognitive appraisals, and social functioning in daily life.

    Science.gov (United States)

    Sheinbaum, Tamara; Kwapil, Thomas R; Ballespí, Sergi; Mitjavila, Mercè; Chun, Charlotte A; Silvia, Paul J; Barrantes-Vidal, Neus

    2015-01-01

    The way in which attachment styles are expressed in the moment as individuals navigate their real-life settings has remained an area largely untapped by attachment research. The present study examined how adult attachment styles are expressed in daily life using experience sampling methodology (ESM) in a sample of 206 Spanish young adults. Participants were administered the Attachment Style Interview (ASI) and received personal digital assistants that signaled them randomly eight times per day for 1 week to complete questionnaires about their current experiences and social context. As hypothesized, participants' momentary affective states, cognitive appraisals, and social functioning varied in meaningful ways as a function of their attachment style. Individuals with an anxious attachment, as compared with securely attached individuals, endorsed experiences that were congruent with hyperactivating tendencies, such as higher negative affect, stress, and perceived social rejection. By contrast, individuals with an avoidant attachment, relative to individuals with a secure attachment, endorsed experiences that were consistent with deactivating tendencies, such as decreased positive states and a decreased desire to be with others when alone. Furthermore, the expression of attachment styles in social contexts was shown to be dependent upon the subjective appraisal of the closeness of social contacts, and not merely upon the presence of social interactions. The findings support the ecological validity of the ASI and the person-by-situation character of attachment theory. Moreover, they highlight the utility of ESM for investigating how the predictions derived from attachment theory play out in the natural flow of real life.

  1. In your eyes: does theory of mind predict impaired life functioning in bipolar disorder?

    Science.gov (United States)

    Purcell, Amanda L; Phillips, Mary; Gruber, June

    2013-12-01

    Deficits in emotion perception and social functioning are strongly implicated in bipolar disorder (BD). Examining theory of mind (ToM) may provide one potential mechanism to explain observed socio-emotional impairments in this disorder. The present study prospectively investigated the relationship between theory of mind performance and life functioning in individuals diagnosed with BD compared to unipolar depression and healthy control groups. Theory of mind (ToM) performance was examined in 26 individuals with remitted bipolar I disorder (BD), 29 individuals with remitted unipolar depression (UD), and 28 healthy controls (CTL) using a well-validated advanced theory of mind task. Accuracy and response latency scores were calculated from the task. Life functioning was measured during a 12 month follow-up session. No group differences for ToM accuracy emerged. However, the BD group exhibited significantly shorter response times than the UD and CTL groups. Importantly, quicker response times in the BD group predicted greater life functioning impairment at a 12-month follow-up, even after controlling for baseline symptoms. The stimuli were static representations of emotional states and do not allow for evaluating the appropriateness of context during emotional communication; due to sample size, neither specific comorbidities nor medication effects were analyzed for the BD and UD groups; preliminary status of theory of mind as a construct. Results suggest that quickened socio-emotional decision making may represent a risk factor for future functional impairment in BD. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Do Metacognitions and Intolerance of Uncertainty Predict Worry in Everyday Life? An Ecological Momentary Assessment Study.

    Science.gov (United States)

    Thielsch, Carolin; Andor, Tanja; Ehring, Thomas

    2015-07-01

    Cognitive models of generalized anxiety disorder (GAD) suggest that excessive worry is due to positive and negative metacognitive beliefs and/or intolerance of uncertainty. Empirical support mainly derives from cross-sectional studies with limited conclusiveness, using self-report measures and thereby possibly causing recall biases. The aim of the present study therefore was to examine the power of these cognitive variables to predict levels of worry in everyday life using Ecological Momentary Assessment (EMA). Metacognitions and intolerance of uncertainty were assessed using well-established self-report questionnaires in 41 nonclinical participants who subsequently completed ratings on worry intensity and burden on a portable device for 1week at seven times a day once every 2hours. Results showed significant associations of negative metacognitive beliefs and intolerance of uncertainty, but not positive metacognitive beliefs, with worry in everyday life. In multilevel regression analyses, a substantial proportion of variance of everyday worry could be accounted for by negative metacognitions over and above trait worry and daily hassles. Intolerance of uncertainty likewise emerged as a valid predictor when tested in isolation, but did not explain additional variance once negative metacognitions were controlled. The findings support current cognitive models of excessive worry and highlight the role of negative metacognitions. By using EMA to assess levels of worry in everyday life, they extend earlier findings focusing exclusively on retrospective questionnaire measures.

  3. Life history predicts risk of species decline in a stochastic world.

    Science.gov (United States)

    Van Allen, Benjamin G; Dunham, Amy E; Asquith, Christopher M; Rudolf, Volker H W

    2012-07-07

    Understanding what traits determine the extinction risk of species has been a long-standing challenge. Natural populations increasingly experience reductions in habitat and population size concurrent with increasing novel environmental variation owing to anthropogenic disturbance and climate change. Recent studies show that a species risk of decline towards extinction is often non-random across species with different life histories. We propose that species with life histories in which all stage-specific vital rates are more evenly important to population growth rate may be less likely to decline towards extinction under these pressures. To test our prediction, we modelled declines in population growth rates under simulated stochastic disturbance to the vital rates of 105 species taken from the literature. Populations with more equally important vital rates, determined using elasticity analysis, declined more slowly across a gradient of increasing simulated environmental variation. Furthermore, higher evenness of elasticity was significantly correlated with a reduced chance of listing as Threatened on the International Union for Conservation of Nature Red List. The relative importance of life-history traits of diverse species can help us infer how natural assemblages will be affected by novel anthropogenic and climatic disturbances.

  4. Fatigue Life Prediction of 2D Woven Ceramic-Matrix Composites at Room and Elevated Temperatures

    Science.gov (United States)

    Longbiao, Li

    2017-02-01

    In this paper, the fatigue life of 2D woven ceramic-matrix composites, i.e., SiC/SiC, SiC/Si-N-C, SiC/Si-B4C, and Nextel 610™/Aluminosilicate, at room and elevated temperatures has been predicted using the micromechanics approach. An effective coefficient of the fiber volume fraction along the loading direction (ECFL) was introduced to describe the fiber architecture of preforms. The Budiansky-Hutchinson-Evans shear-lag model was used to describe the microstress field of the damaged composite considering fibers failure. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. The interface shear stress and fibers strength degradation model and oxidation region propagation model have been adopted to analyze the fatigue and oxidation effects on fatigue life of the composite, which is controlled by interface frictional slip and diffusion of oxygen gas through matrix multicrackings. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface/fiber oxidation model, interface wear model and fibers statistical failure model at elevated temperatures, based on the assumption that the fiber strength is subjected to two-parameter Weibull distribution and the load carried by broken and intact fibers satisfy the Global Load Sharing (GLS) criterion. When the broken fibers fraction approaches to the critical value, the composites fatigue fractures. The fatigue life S-N curves of 2D SiC/SiC, SiC/Si-N-C, SiC/Si-B4C, and Nextel 610™/Aluminosilicate composites at room temperature and 800, 1000 and 1200 °C in air and steam have been predicted.

  5. A physically based analytical model of flood frequency curves

    Science.gov (United States)

    Basso, S.; Schirmer, M.; Botter, G.

    2016-09-01

    Predicting magnitude and frequency of floods is a key issue in hydrology, with implications in many fields ranging from river science and geomorphology to the insurance industry. In this paper, a novel physically based approach is proposed to estimate the recurrence intervals of seasonal flow maxima. The method links the extremal distribution of streamflows to the stochastic dynamics of daily discharge, providing an analytical expression of the seasonal flood frequency curve. The parameters involved in the formulation embody climate and landscape attributes of the contributing catchment and can be estimated from daily rainfall and streamflow data. Only one parameter, which is linked to the antecedent wetness condition in the watershed, needs to be calibrated on the observed maxima. The performance of the method is discussed through a set of applications in four rivers featuring heterogeneous daily flow regimes. The model provides reliable estimates of seasonal maximum flows in different climatic settings and is able to capture diverse shapes of flood frequency curves emerging in erratic and persistent flow regimes. The proposed method exploits experimental information on the full range of discharges experienced by rivers. As a consequence, model performances do not deteriorate when the magnitude of events with return times longer than the available sample size is estimated. The approach provides a framework for the prediction of floods based on short data series of rainfall and daily streamflows that may be especially valuable in data scarce regions of the world.

  6. Simplified Physics Based Models Research Topical Report on Task #2

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Srikanta; Ganesh, Priya

    2014-10-31

    We present a simplified-physics based approach, where only the most important physical processes are modeled, to develop and validate simplified predictive models of CO2 sequestration in deep saline formation. The system of interest is a single vertical well injecting supercritical CO2 into a 2-D layered reservoir-caprock system with variable layer permeabilities. We use a set of well-designed full-physics compositional simulations to understand key processes and parameters affecting pressure propagation and buoyant plume migration. Based on these simulations, we have developed correlations for dimensionless injectivity as a function of the slope of fractional-flow curve, variance of layer permeability values, and the nature of vertical permeability arrangement. The same variables, along with a modified gravity number, can be used to develop a correlation for the total storage efficiency within the CO2 plume footprint. Similar correlations are also developed to predict the average pressure within the injection reservoir, and the pressure buildup within the caprock.

  7. REMAINING LIFE TIME PREDICTION OF BEARINGS USING K-STAR ALGORITHM – A STATISTICAL APPROACH

    Directory of Open Access Journals (Sweden)

    R. SATISHKUMAR

    2017-01-01

    Full Text Available The role of bearings is significant in reducing the down time of all rotating machineries. The increasing trend of bearing failures in recent times has triggered the need and importance of deployment of condition monitoring. There are multiple factors associated to a bearing failure while it is in operation. Hence, a predictive strategy is required to evaluate the current state of the bearings in operation. In past, predictive models with regression techniques were widely used for bearing lifetime estimations. The Objective of this paper is to estimate the remaining useful life of bearings through a machine learning approach. The ultimate objective of this study is to strengthen the predictive maintenance. The present study was done using classification approach following the concepts of machine learning and a predictive model was built to calculate the residual lifetime of bearings in operation. Vibration signals were acquired on a continuous basis from an experiment wherein the bearings are made to run till it fails naturally. It should be noted that the experiment was carried out with new bearings at pre-defined load and speed conditions until the bearing fails on its own. In the present work, statistical features were deployed and feature selection process was carried out using J48 decision tree and selected features were used to develop the prognostic model. The K-Star classification algorithm, a supervised machine learning technique is made use of in building a predictive model to estimate the lifetime of bearings. The performance of classifier was cross validated with distinct data. The result shows that the K-Star classification model gives 98.56% classification accuracy with selected features.

  8. Predicting water quality criteria for protecting aquatic life from physicochemical properties of metals or metalloids.

    Science.gov (United States)

    Wu, Fengchang; Mu, Yunsong; Chang, Hong; Zhao, Xiaoli; Giesy, John P; Wu, K Benjamin

    2013-01-02

    Metals are widely distributed pollutants in water and can have detrimental effects on some aquatic life and humans. Over the past few decades, the United States Environmental Protection Agency (U.S. EPA) has published a series of criteria guidelines, which contain specific criteria maximum concentrations (CMCs) for 10 metals. However, CMCs for other metals are still lacking because of financial, practical, or ethical restrictions on toxicity testing. Herein, a quantitative structure activity relationship (QSAR) method was used to develop a set of predictive relationships, based on physical and chemical characteristics of metals, and predict acute toxicities of each species for five phyla and eight families of organisms for 25 metals or metalloids. In addition, species sensitivity distributions (SSDs) were developed as independent methods for determining predictive CMCs. The quantitative ion character-activity relationships (QICAR) analysis showed that the softness index (σp), maximum complex stability constants (log -β(n)), electrochemical potential (ΔE(0)), and covalent index (X(m)(2)r) were the minimum set of structure parameters required to predict toxicity of metals to eight families of representative organisms. Predicted CMCs for 10 metals are in reasonable agreement with those recommended previously by U.S. EPA within a difference of 1.5 orders of magnitude. CMCs were significantly related to σp (r(2) = 0.76, P = 7.02 × 10(-9)) and log -β(n) (r(2) = 0.73, P = 3.88 × 10(-8)). The novel QICAR-SSD model reported here is a rapid, cost-effective, and reasonably accurate method, which can provide a beneficial supplement to existing methodologies for developing preliminarily screen level toxicities or criteria for metals, for which little or no relevant information on the toxicity to particular classes of aquatic organisms exists.

  9. Bayesian probabilistic model for life prediction and fault mode classification of solid state luminaires

    Energy Technology Data Exchange (ETDEWEB)

    Lall, Pradeep [Auburn Univ., Auburn, AL (United States); Wei, Junchao [Auburn Univ., Auburn, AL (United States); Sakalaukus, Peter [Auburn Univ., Auburn, AL (United States)

    2014-06-22

    A new method has been developed for assessment of the onset of degradation in solid state luminaires to classify failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. Failure modes of the test population of the lamps have been studied to understand the failure mechanisms in 85°C/85%RH accelerated test. Results indicate that the dominant failure mechanism is the discoloration of the LED encapsulant inside the lamps which is the likely cause for the luminous flux degradation and the color shift. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identify luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. The α-λ plots have been used to evaluate the robustness of the proposed methodology. Results show that the predicted degradation for the lamps tracks the true degradation observed during 85°C/85%RH during accelerated life test fairly closely within the ±20% confidence bounds. Correlation of model prediction with experimental results indicates that the presented methodology allows the early identification of the onset of failure much prior to development of complete failure distributions and can be used for assessing the damage state of SSLs in fairly large deployments. It is expected that, the new prediction technique will allow the development of failure distributions without testing till L70 life for the manifestation of failure.

  10. A review of quality of life after predictive testing for and earlier identification of neurodegenerative diseases.

    Science.gov (United States)

    Paulsen, Jane S; Nance, Martha; Kim, Ji-In; Carlozzi, Noelle E; Panegyres, Peter K; Erwin, Cheryl; Goh, Anita; McCusker, Elizabeth; Williams, Janet K

    2013-11-01

    The past decade has witnessed an explosion of evidence suggesting that many neurodegenerative diseases can be detected years, if not decades, earlier than previously thought. To date, these scientific advances have not provoked any parallel translational or clinical improvements. There is an urgency to capitalize on this momentum so earlier detection of disease can be more readily translated into improved health-related quality of life for families at risk for, or suffering with, neurodegenerative diseases. In this review, we discuss health-related quality of life (HRQOL) measurement in neurodegenerative diseases and the importance of these "patient reported outcomes" for all clinical research. Next, we address HRQOL following early identification or predictive genetic testing in some neurodegenerative diseases: Huntington disease, Alzheimer's disease, Parkinson's disease, Dementia with Lewy bodies, frontotemporal dementia, amyotrophic lateral sclerosis, prion diseases, hereditary ataxias, Dentatorubral-pallidoluysian atrophy and Wilson's disease. After a brief report of available direct-to-consumer genetic tests, we address the juxtaposition of earlier disease identification with assumed reluctance toward predictive genetic testing. Forty-one studies examining health-related outcomes following predictive genetic testing for neurodegenerative disease suggested that (a) extreme or catastrophic outcomes are rare; (b) consequences commonly include transiently increased anxiety and/or depression; (c) most participants report no regret; (d) many persons report extensive benefits to receiving genetic information; and (e) stigmatization and discrimination for genetic diseases are poorly understood and policy and laws are needed. Caution is appropriate for earlier identification of neurodegenerative diseases but findings suggest further progress is safe, feasible and likely to advance clinical care.

  11. A Review of Quality of Life after Predictive Testing for and Earlier Identification of Neurodegenerative Diseases

    Science.gov (United States)

    Paulsen, Jane S.; Nance, Martha; Kim, Ji-In; Carlozzi, Noelle E.; Panegyres, Peter K.; Erwin, Cheryl; Goh, Anita; McCusker, Elizabeth; Williams, Janet K.

    2013-01-01

    The past decade has witnessed an explosion of evidence suggesting that many neurodegenerative diseases can be detected years, if not decades, earlier than previously thought. To date, these scientific advances have not provoked any parallel translational or clinical improvements. There is an urgency to capitalize on this momentum so earlier detection of disease can be more readily translated into improved health-related quality of life for families at risk for, or suffering with, neurodegenerative diseases. In this review, we discuss health-related quality of life (HRQOL) measurement in neurodegenerative diseases and the importance of these “patient reported outcomes” for all clinical research. Next, we address HRQOL following early identification or predictive genetic testing in some neurodegenerative diseases: Huntington disease, Alzheimer's disease, Parkinson's disease, Dementia with Lewy bodies, frontotemporal dementia, amyotrophic lateral sclerosis, prion diseases, hereditary ataxias, Dentatorubral-pallidoluysian atrophy and Wilson's disease. After a brief report of available direct-to-consumer genetic tests, we address the juxtaposition of earlier disease identification with assumed reluctance towards predictive genetic testing. Forty-one studies examining health related outcomes following predictive genetic testing for neurodegenerative disease suggested that (a) extreme or catastrophic outcomes are rare; (b) consequences commonly include transiently increased anxiety and/or depression; (c) most participants report no regret; (d) many persons report extensive benefits to receiving genetic information; and (e) stigmatization and discrimination for genetic diseases are poorly understood and policy and laws are needed. Caution is appropriate for earlier identification of neurodegenerative diseases but findings suggest further progress is safe, feasible and likely to advance clinical care. PMID:24036231

  12. A Critical Plane-energy Model for Multiaxial Fatigue Life Prediction of Homogeneous and Heterogeneous Materials

    Science.gov (United States)

    Wei, Haoyang

    A new critical plane-energy model is proposed in this thesis for multiaxial fatigue life prediction of homogeneous and heterogeneous materials. Brief review of existing methods, especially on the critical plane-based and energy-based methods, are given first. Special focus is on one critical plane approach which has been shown to work for both brittle and ductile metals. The key idea is to automatically change the critical plane orientation with respect to different materials and stress states. One potential drawback of the developed model is that it needs an empirical calibration parameter for non-proportional multiaxial loadings since only the strain terms are used and the out-of-phase hardening cannot be considered. The energy-based model using the critical plane concept is proposed with help of the Mroz-Garud hardening rule to explicitly include the effect of non-proportional hardening under fatigue cyclic loadings. Thus, the empirical calibration for non-proportional loading is not needed since the out-of-phase hardening is naturally included in the stress calculation. The model predictions are compared with experimental data from open literature and it is shown the proposed model can work for both proportional and non-proportional loadings without the empirical calibration. Next, the model is extended for the fatigue analysis of heterogeneous materials integrating with finite element method. Fatigue crack initiation of representative volume of heterogeneous materials is analyzed using the developed critical plane-energy model and special focus is on the microstructure effect on the multiaxial fatigue life predictions. Several conclusions and future work is drawn based on the proposed study.

  13. Physics-Based Hazard Assessment for Critical Structures Near Large Earthquake Sources

    Science.gov (United States)

    Hutchings, L.; Mert, A.; Fahjan, Y.; Novikova, T.; Golara, A.; Miah, M.; Fergany, E.; Foxall, W.

    2017-06-01

    We argue that for critical structures near large earthquake sources: (1) the ergodic assumption, recent history, and simplified descriptions of the hazard are not appropriate to rely on for earthquake ground motion prediction and can lead to a mis-estimation of the hazard and risk to structures; (2) a physics-based approach can address these issues; (3) a physics-based source model must be provided to generate realistic phasing effects from finite rupture and model near-source ground motion correctly; (4) wave propagations and site response should be site specific; (5) a much wider search of possible sources of ground motion can be achieved computationally with a physics-based approach; (6) unless one utilizes a physics-based approach, the hazard and risk to structures has unknown uncertainties; (7) uncertainties can be reduced with a physics-based approach, but not with an ergodic approach; (8) computational power and computer codes have advanced to the point that risk to structures can be calculated directly from source and site-specific ground motions. Spanning the variability of potential ground motion in a predictive situation is especially difficult for near-source areas, but that is the distance at which the hazard is the greatest. The basis of a "physical-based" approach is ground-motion syntheses derived from physics and an understanding of the earthquake process. This is an overview paper and results from previous studies are used to make the case for these conclusions. Our premise is that 50 years of strong motion records is insufficient to capture all possible ranges of site and propagation path conditions, rupture processes, and spatial geometric relationships between source and site. Predicting future earthquake scenarios is necessary; models that have little or no physical basis but have been tested and adjusted to fit available observations can only "predict" what happened in the past, which should be considered description as opposed to prediction

  14. A Hybrid Prognostic Approach for Remaining Useful Life Prediction of Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Wen-An Yang

    2016-01-01

    Full Text Available Lithium-ion battery is a core component of many systems such as satellite, spacecraft, and electric vehicles and its failure can lead to reduced capability, downtime, and even catastrophic breakdowns. Remaining useful life (RUL prediction of lithium-ion batteries before the future failure event is extremely crucial for proactive maintenance/safety actions. This study proposes a hybrid prognostic approach that can predict the RUL of degraded lithium-ion batteries using physical laws and data-driven modeling simultaneously. In this hybrid prognostic approach, the relevant vectors obtained with the selective kernel ensemble-based relevance vector machine (RVM learning algorithm are fitted to the physical degradation model, which is then extrapolated to failure threshold for estimating the RUL of the lithium-ion battery of interest. The experimental results indicated that the proposed hybrid prognostic approach can accurately predict the RUL of degraded lithium-ion batteries. Empirical comparisons show that the proposed hybrid prognostic approach using the selective kernel ensemble-based RVM learning algorithm performs better than the hybrid prognostic approaches using the popular learning algorithms of feedforward artificial neural networks (ANNs like the conventional backpropagation (BP algorithm and support vector machines (SVMs. In addition, an investigation is also conducted to identify the effects of RVM learning algorithm on the proposed hybrid prognostic approach.

  15. Recent developments on SMA actuators: predicting the actuation fatigue life for variable loading schemes

    Science.gov (United States)

    Wheeler, Robert W.; Lagoudas, Dimitris C.

    2017-04-01

    Shape memory alloys (SMAs), due to their ability to repeatably recover substantial deformations under applied mechanical loading, have the potential to impact the aerospace, automotive, biomedical, and energy industries as weight and volume saving replacements for conventional actuators. While numerous applications of SMA actuators have been flight tested and can be found in industrial applications, these actuators are generally limited to non-critical components, are not widely implemented and frequently one-off designs, and are generally overdesigned due to a lack of understanding of the effect of the loading path on the fatigue life and the lack of an accurate method for predicting actuator lifetimes. In recent years, multiple research efforts have increased our understanding of the actuation fatigue process of SMAs. These advances can be utilized to predict the fatigue lives and failure loads in SMA actuators. Additionally, these prediction methods can be implemented in order to intelligently design actuators in accordance with their fatigue and failure limits. In the following paper, both simple and complex thermomechanical loading paths have been considered. Experimental data was utilized from two material systems: equiatomic Nickel-Titanium and Nickelrich Nickel-Titanium.

  16. Life histories of hosts and pathogens predict patterns in tropical fungal plant diseases.

    Science.gov (United States)

    García-Guzmán, Graciela; Heil, Martin

    2014-03-01

    Plant pathogens affect the fitness of their hosts and maintain biodiversity. However, we lack theories to predict the type and intensity of infections in wild plants. Here we demonstrate using fungal pathogens of tropical plants that an examination of the life histories of hosts and pathogens can reveal general patterns in their interactions. Fungal infections were more commonly reported for light-demanding than for shade-tolerant species and for evergreen rather than for deciduous hosts. Both patterns are consistent with classical defence theory, which predicts lower resistance in fast-growing species and suggests that the deciduous habit can reduce enemy populations. In our literature survey, necrotrophs were found mainly to infect shade-tolerant woody species whereas biotrophs dominated in light-demanding herbaceous hosts. Far-red signalling and its inhibitory effects on jasmonic acid signalling are likely to explain this phenomenon. Multiple changes between the necrotrophic and the symptomless endophytic lifestyle at the ecological and evolutionary scale indicate that endophytes should be considered when trying to understand large-scale patterns in the fungal infections of plants. Combining knowledge about the molecular mechanisms of pathogen resistance with classical defence theory enables the formulation of testable predictions concerning general patterns in the infections of wild plants by fungal pathogens. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Thermomechanical fatigue – Damage mechanisms and mechanism-based life prediction methods

    Indian Academy of Sciences (India)

    H-J Christ; A Jung; H J Maier; R Teteruk

    2003-02-01

    An existing extensive database on the isothermal and thermomechanical fatigue behaviour of high-temperature titanium alloy IMI 834 and dispersoidstrengthened aluminum alloy X8019 in SiC particle-reinforced as well as unreinforced conditions was used to evaluate both the adaptability of fracture mechanics approaches to TMF and the resulting predictive capabilities of determining material life by crack propagation consideration. Selection of the correct microstructural concepts was emphasised and these concepts were, then adjusted by using data from independent experiments in order to avoid any sort of fitting. It is shown that the cyclic -integral ($\\Delta J_{\\text{eff}}$ concept) is suitable to predict the cyclic lifetime for conditions where the total crack propagation rate is approximately identical to pure fatigue crack growth velocity. In the case that crack propagation is strongly affected by creep, the creep–fatigue damage parameter $\\Delta_{C\\ F}$ introduced by Riedel can be successfully applied. If environmental effects are very pronounced, the accelerating influence of corrosion on fatigue crack propagation can no longer implicitly be taken into account in the fatigue crack growth law. Instead, a linear combination of the crack growth rate contributions from plain fatigue (determined in vacuum) and from environmental attack is assumed and found to yield a satisfactory prediction, if the relevant corrosion process is taken into account.

  18. A New Approach to Predict the Fish Fillet Shelf-Life in Presence of Natural Preservative Agents.

    Science.gov (United States)

    Giuffrida, Alessandro; Giarratana, Filippo; Valenti, Davide; Muscolino, Daniele; Parisi, Roberta; Parco, Alessio; Marotta, Stefania; Ziino, Graziella; Panebianco, Antonio

    2017-04-13

    Three data sets concerning the behaviour of spoilage flora of fillets treated with natural preservative substances (NPS) were used to construct a new kind of mathematical predictive model. This model, unlike other ones, allows expressing the antibacterial effect of the NPS separately from the prediction of the growth rate. This approach, based on the introduction of a parameter into the predictive primary model, produced a good fitting of observed data and allowed characterising quantitatively the increase of shelf-life of fillets.

  19. Ambulation in adults with myelomeningocele. Is it possible to predict the level of ambulation in early life?

    DEFF Research Database (Denmark)

    Seitzberg, A.; Lind, M.; Biering-Sørensen, Fin

    2008-01-01

    OBJECTIVE: The objective of this study was to evaluate the prediction of ambulation in adults with myelomeningocele from muscle strength testing and ambulation in early life. MATERIALS AND METHODS: Fifty-two myelomeningocele (MMC) individuals at the age 18-37 years at follow-up were studied...... with muscle strength within the first year of life, 7 achieved the predicted ambulatory function, 6 had a better, and 7 a poorer function. Of 32 individuals with known muscle strength at the age of 5-8 years, 10 had function as predicted, 5 a better ambulatory function, and 17 had a poorer ambulation in adult...... life than predicted. Good strength in quadriceps muscles gave significant better prospect for adult walking. Of the 52 participants, 41 retained their ambulation status from 5-8 years of age. CONCLUSION: For MMC individuals with motor levels L3-L5, adult ambulatory function cannot be determined from...

  20. Sleep quality predicts quality of life in chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Tzahit Simon-Tuval

    2010-12-01

    Full Text Available Steven M Scharf1*, Nimrod Maimon2*, Tzahit Simon-Tuval3, Barbara J Bernhard-Scharf4, Haim Reuveni2, Ariel Tarasiuk21Department of Pulmonary and Critical Care, University of Maryland, Baltimore, MD, USA; 2Faculty of Health Sciences, Ben-Gurion University, Beersheba, Israel; 3Guilford Glazer School of Business and Management, Ben Gurion University, Beersheba, Israel; 4Mt. Washington Pediatric Hospital, Baltimore, MD, USA; The study was performed at the Soroka University Medical Center, Beer Sheva, Israel*Drs Scharf and Maimon contributed equally to this manuscript.Purpose: Chronic obstructive pulmonary disease (COPD patients may suffer from poor sleep and health-related quality of life. We hypothesized that disturbed sleep in COPD is correlated with quality of life.Methods: In 180 patients with COPD (forced expired volume in 1 second [FEV1] 47.6 ± 15.2% predicted, 77.8% male, aged 65.9 ± 11.7 years, we administered general (Health Utilities Index 3 and disease-specific (St George’s Respiratory questionnaires and an index of disturbed sleep (Pittsburgh Sleep Quality Index.Results: Overall scores indicated poor general (Health Utilities Index 3: 0.52 ± 0.38, disease-specific (St George’s: 57.0 ± 21.3 quality of life and poor sleep quality (Pittsburgh 11.0 ± 5.4. Sleep time correlated with the number of respiratory and anxiety symptoms reported at night. Seventy-seven percent of the patients had Pittsburg scores >5, and the median Pittsburgh score was 12. On multivariate regression, the Pittsburgh Sleep Quality Index was an independent predictor of both the Health Utilities Index 3 and the St George’s scores, accounting for 3% and 5%, respectively, of the scores. Only approximately 25% of the patients demonstrated excessive sleepiness (Epworth Sleepiness Scale >9.Conclusions: Most patients with COPD suffer disturbed sleep. Sleep quality was correlated with general and disease-specific quality of life. Only a minority of COPD patients

  1. Bayesian techniques for fatigue life prediction and for inference in linear time dependent PDEs

    KAUST Repository

    Scavino, Marco

    2016-01-08

    In this talk we introduce first the main characteristics of a systematic statistical approach to model calibration, model selection and model ranking when stress-life data are drawn from a collection of records of fatigue experiments. Focusing on Bayesian prediction assessment, we consider fatigue-limit models and random fatigue-limit models under different a priori assumptions. In the second part of the talk, we present a hierarchical Bayesian technique for the inference of the coefficients of time dependent linear PDEs, under the assumption that noisy measurements are available in both the interior of a domain of interest and from boundary conditions. We present a computational technique based on the marginalization of the contribution of the boundary parameters and apply it to inverse heat conduction problems.

  2. Life cycle assessment needs predictive spatial modelling for biodiversity and ecosystem services

    Science.gov (United States)

    Chaplin-Kramer, Rebecca; Sim, Sarah; Hamel, Perrine; Bryant, Benjamin; Noe, Ryan; Mueller, Carina; Rigarlsford, Giles; Kulak, Michal; Kowal, Virginia; Sharp, Richard; Clavreul, Julie; Price, Edward; Polasky, Stephen; Ruckelshaus, Mary; Daily, Gretchen

    2017-04-01

    International corporations in an increasingly globalized economy exert a major influence on the planet's land use and resources through their product design and material sourcing decisions. Many companies use life cycle assessment (LCA) to evaluate their sustainability, yet commonly-used LCA methodologies lack the spatial resolution and predictive ecological information to reveal key impacts on climate, water and biodiversity. We present advances for LCA that integrate spatially explicit modelling of land change and ecosystem services in a Land-Use Change Improved (LUCI)-LCA. Comparing increased demand for bioplastics derived from two alternative feedstock-location scenarios for maize and sugarcane, we find that the LUCI-LCA approach yields results opposite to those of standard LCA for greenhouse gas emissions and water consumption, and of different magnitudes for soil erosion and biodiversity. This approach highlights the importance of including information about where and how land-use change and related impacts will occur in supply chain and innovation decisions.

  3. Implicit theories about willpower predict self-regulation and grades in everyday life.

    Science.gov (United States)

    Job, Veronika; Walton, Gregory M; Bernecker, Katharina; Dweck, Carol S

    2015-04-01

    Laboratory research shows that when people believe that willpower is an abundant (rather than highly limited) resource they exhibit better self-control after demanding tasks. However, some have questioned whether this "nonlimited" theory leads to squandering of resources and worse outcomes in everyday life when demands on self-regulation are high. To examine this, we conducted a longitudinal study, assessing students' theories about willpower and tracking their self-regulation and academic performance. As hypothesized, a nonlimited theory predicted better self-regulation (better time management and less procrastination, unhealthy eating, and impulsive spending) for students who faced high self-regulatory demands. Moreover, among students taking a heavy course load, those with a nonlimited theory earned higher grades, which was mediated by less procrastination. These findings contradict the idea that a limited theory helps people allocate their resources more effectively; instead, it is people with the nonlimited theory who self-regulate well in the face of high demands.

  4. Fundamental understanding and life prediction of stress corrosion cracking in BWRs and energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, P.L.; Ford, F.P. [General Electric, Schenectady, NY (United States). Corporate Research and Development Center

    1998-03-01

    The objective of this paper is to present an approach for design and lifetime evaluation of environmental cracking based on experimental and fundamental modeling of the underlying processes operative in crack advance. In detailed this approach and its development and quantification for energy (hot water) systems, the requirements for a life prediction methodology will be highlighted and the shortcomings of the existing design and lifetime evaluation codes reviewed. Examples are identified of its use in a variety of cracking systems, such as stainless steels, low alloy steels, nickel base alloys, and irradiation assisted stress corrosion cracking in boiling water reactor (BWR) water, as well as preliminary use for low alloy steel and Alloy 600 in pressurized water reactors (PWRs) and turbine steels in steam turbines. Identification of the common aspects with environmental cracking in other hot water systems provides a secure basis for its extension to related energy systems. 166 refs., 49 figs.

  5. Failure Mechanisms and Life Prediction of Thermal and Environmental Barrier Coatings under Thermal Gradients

    Science.gov (United States)

    Zju, Dongming; Ghosn, Louis J.; Miller, Robert A.

    2008-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) will play an increasingly important role in gas turbine engines because of their ability to further raise engine temperatures. However, the issue of coating durability is of major concern under high-heat-flux conditions. In particular, the accelerated coating delamination crack growth under the engine high heat-flux conditions is not well understood. In this paper, a laser heat flux technique is used to investigate the coating delamination crack propagation under realistic temperature-stress gradients and thermal cyclic conditions. The coating delamination mechanisms are investigated under various thermal loading conditions, and are correlated with coating dynamic fatigue, sintering and interfacial adhesion test results. A coating life prediction framework may be realized by examining the crack initiation and propagation driving forces for coating failure under high-heat-flux test conditions.

  6. Development and Life Prediction of Erosion Resistant Turbine Low Conductivity Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

    2010-01-01

    Future rotorcraft propulsion systems are required to operate under highly-loaded conditions and in harsh sand erosion environments, thereby imposing significant material design and durability issues. The incorporation of advanced thermal barrier coatings (TBC) in high pressure turbine systems enables engine designs with higher inlet temperatures, thus improving the engine efficiency, power density and reliability. The impact and erosion resistance of turbine thermal barrier coating systems are crucial to the turbine coating technology application, because a robust turbine blade TBC system is a prerequisite for fully utilizing the potential coating technology benefit in the rotorcraft propulsion. This paper describes the turbine blade TBC development in addressing the coating impact and erosion resistance. Advanced thermal barrier coating systems with improved performance have also been validated in laboratory simulated engine erosion and/or thermal gradient environments. A preliminary life prediction modeling approach to emphasize the turbine blade coating erosion is also presented.

  7. NASA Langley developments in response calculations needed for failure and life prediction

    Science.gov (United States)

    Housner, Jerrold M.

    1993-10-01

    NASA Langley developments in response calculations needed for failure and life predictions are discussed. Topics covered include: structural failure analysis in concurrent engineering; accuracy of independent regional modeling demonstrated on classical example; functional interface method accurately joins incompatible finite element models; interface method for insertion of local detail modeling extended to curve pressurized fuselage window panel; interface concept for joining structural regions; motivation for coupled 2D-3D analysis; compression panel with discontinuous stiffener coupled 2D-3D model and axial surface strains at the middle of the hat stiffener; use of adaptive refinement with multiple methods; adaptive mesh refinement; and studies on quantity effect of bow-type initial imperfections on reliability of stiffened panels.

  8. Empirical and physics based mathematical models of uranium hydride decomposition kinetics with quantified uncertainties.

    Energy Technology Data Exchange (ETDEWEB)

    Salloum, Maher N.; Gharagozloo, Patricia E.

    2013-10-01

    Metal particle beds have recently become a major technique for hydrogen storage. In order to extract hydrogen from such beds, it is crucial to understand the decomposition kinetics of the metal hydride. We are interested in obtaining a a better understanding of the uranium hydride (UH3) decomposition kinetics. We first developed an empirical model by fitting data compiled from different experimental studies in the literature and quantified the uncertainty resulting from the scattered data. We found that the decomposition time range predicted by the obtained kinetics was in a good agreement with published experimental results. Secondly, we developed a physics based mathematical model to simulate the rate of hydrogen diffusion in a hydride particle during the decomposition. We used this model to simulate the decomposition of the particles for temperatures ranging from 300K to 1000K while propagating parametric uncertainty and evaluated the kinetics from the results. We compared the kinetics parameters derived from the empirical and physics based models and found that the uncertainty in the kinetics predicted by the physics based model covers the scattered experimental data. Finally, we used the physics-based kinetics parameters to simulate the effects of boundary resistances and powder morphological changes during decomposition in a continuum level model. We found that the species change within the bed occurring during the decomposition accelerates the hydrogen flow by increasing the bed permeability, while the pressure buildup and the thermal barrier forming at the wall significantly impede the hydrogen extraction.

  9. Satellite Lithium-Ion Battery Remaining Cycle Life Prediction with Novel Indirect Health Indicator Extraction

    Directory of Open Access Journals (Sweden)

    Haitao Liao

    2013-07-01

    Full Text Available Prognostics and remaining useful life (RUL estimation for lithium-ion batteries play an important role in intelligent battery management systems (BMS. The capacity is often used as the fade indicator for estimating the remaining cycle life of a lithium-ion battery. For spacecraft requiring high reliability and long lifetime, in-orbit RUL estimation and reliability verification on ground should be carefully addressed. However, it is quite challenging to monitor and estimate the capacity of a lithium-ion battery on-line in satellite applications. In this work, a novel health indicator (HI is extracted from the operating parameters of a lithium-ion battery to quantify battery degradation. Moreover, the Grey Correlation Analysis (GCA is utilized to evaluate the similarities between the extracted HI and the battery’s capacity. The result illustrates the effectiveness of using this new HI for fading indication. Furthermore, we propose an optimized ensemble monotonic echo state networks (En_MONESN algorithm, in which the monotonic constraint is introduced to improve the adaptivity of degradation trend estimation, and ensemble learning is integrated to achieve high stability and precision of RUL prediction. Experiments with actual testing data show the efficiency of our proposed method in RUL estimation and degradation modeling for the satellite lithium-ion battery application.

  10. Cyclic fatigue damage characteristics observed for simple loadings extended to multiaxial life prediction

    Science.gov (United States)

    Jones, David J.; Kurath, Peter

    1988-01-01

    Fully reversed uniaxial strain controlled fatigue tests were performed on smooth cylindrical specimens made of 304 stainless steel. Fatigue life data and cracking observations for uniaxial tests were compared with life data and cracking behavior observed in fully reversed torsional tests. It was determined that the product of maximum principle strain amplitude and maximum principle stress provided the best correlation of fatigue lives for these two loading conditions. Implementation of this parameter is in agreement with observed physical damage and it accounts for the variation of stress-strain response, which is unique to specific loading conditions. Biaxial fatigue tests were conducted on tubular specimens employing both in-phase and out-of-phase tension torsion cyclic strain paths. Cracking observations indicated that the physical damage which occurred in the biaxial tests was similar to the damage observed in uniaxial and torsional tests. The Smith, Watson, and Topper parameter was then extended to predict the fatigue lives resulting from the more complex loading conditions.

  11. Attachment Style Predicts Affect, Cognitive Appraisals, and Social Functioning in Daily Life

    Directory of Open Access Journals (Sweden)

    Tamara eSheinbaum

    2015-03-01

    Full Text Available The way in which attachment styles are expressed in the moment as individuals navigate their real-life settings has remained an area largely untapped by attachment research. The present study examined how adult attachment styles are expressed in daily life using Experience Sampling Methodology (ESM in a sample of 206 Spanish young adults. Participants were administered the Attachment Style Interview and received personal digital assistants that signaled them randomly eight times per day for one week to complete questionnaires about their current experiences and social context. As hypothesized, participants’ momentary affective states, cognitive appraisals, and social functioning varied in meaningful ways as a function of their attachment style. Individuals with an anxious attachment, as compared with securely attached individuals, endorsed experiences that were congruent with hyperactivating tendencies, such as higher negative affect, stress, and perceived social rejection. By contrast, individuals with an avoidant attachment, relative to individuals with a secure attachment, endorsed experiences that were consistent with deactivating tendencies, such as decreased positive states and a decreased desire to be with others when alone. Furthermore, the expression of attachment styles in social contexts was shown to be dependent upon the subjective appraisal of the closeness of social contacts, and not merely upon the presence of social interactions. The findings support the ecological validity of the Attachment Style Interview and the person-by-situation character of attachment theory. Moreover, they highlight the utility of ESM for investigating how the predictions derived from attachment theory play out in the natural flow of real life.

  12. Arrhenius equation modeling for the shelf life prediction of tomato paste containing a natural preservative.

    Science.gov (United States)

    Jafari, Seid Mahdi; Ganje, Mohammad; Dehnad, Danial; Ghanbari, Vahid; Hajitabar, Javad

    2017-04-28

    The shelf life of tomato paste with microencapsulated olive leaf extract was compared with that of samples containing a commercial preservative by accelerated shelf life testing. Based on previous studies showing that olive leaf extract as a rich source of phenolic compounds can have antimicrobial properties, application of its encapsulated form to improve the storage stability of tomato paste is proposed here. Regarding total soluble solids, the control and the sample containing 1000 µg g(-1) sodium benzoate had the lowest (Q10  = 1.63) and highest (Q10  = 1.88) sensitivity to temperature changes respectively; also, the microencapsulated sample containing 1000 µg g(-1) encapsulated olive leaf extract (Q10  = 1.83) followed the sample containing 1000 µg g(-1) sodium benzoate in terms of the highest kinetic rates. In the case of consistency, the lowest and highest activation energies (Ea ) corresponded to samples containing 1000 µg g(-1) non-encapsulated olive leaf extract and 1000 µg g(-1) microencapsulated olive leaf extract respectively. Interestingly, samples containing microencapsulated olive leaf extract could maintain the original quality of the tomato paste very well, while those with non-encapsulated olive leaf extract rated the worst performance (among all specimens) in terms of maintaining their quality indices for a long time period. Overall, the shelf life equation was able to predict the consistency index of all tomato paste samples during long-time storage with high precision. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. A Methodology to Predict Uniform Material Fatigue Life of Cast Iron: Law for Cast Iron%A Methodology to Predict Uniform Material Fatigue Life of Cast Iron: Law for Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Sinan Korkmaz

    2011-01-01

    Mechanical, physical and manufacturing properties of east iron make it attractive for many fields of application, such as cranks and cylinder holds. As in design of all metals, fatigue life prediction is an intrinsic part of the design process of structural sections that are made of cast iron. A methodology to predict high-cycle fatigue life of cast iron is proposed. Stress amplitude-strain amplitude, strain amplitude-number of loading cycles relationships of cast iron are investigated. Also, fatigue life prediction in terms of Smith, Watson and Topper parameter is carried out using the proposed method. Results indicate that the analytical outcomes of the proposed methodology are in good accordance with the experimental data for the two studied types of cast iron: EN-GJS-400 and EN-GJS-600.

  14. A 3.5 year diary study: Remembering and life story importance are predicted by different event characteristics.

    Science.gov (United States)

    Thomsen, Dorthe Kirkegaard; Jensen, Thomas; Holm, Tine; Olesen, Martin Hammershøj; Schnieber, Anette; Tønnesvang, Jan

    2015-11-01

    Forty-five participants described and rated two events each week during their first term at university. After 3.5 years, we examined whether event characteristics rated in the diary predicted remembering, reliving, and life story importance at the follow-up. In addition, we examined whether ratings of life story importance were consistent across a three year interval. Approximately 60% of events were remembered, but only 20% of these were considered above medium importance to life stories. Higher unusualness, rehearsal, and planning predicted whether an event was remembered 3.5 years later. Higher goal-relevance, importance, emotional intensity, and planning predicted life story importance 3.5 years later. There was a moderate correlation between life story importance rated three months after the diary and rated at the 3.5 year follow-up. The results suggest that autobiographical memory and life stories are governed by different mechanisms and that life story memories are characterized by some degree of stability. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. A Physics-Based Temperature Stabilization Criterion for Thermal Testing

    Science.gov (United States)

    Rickman, Steven L.; Ungar, Eugene K.

    2009-01-01

    Spacecraft testing specifications differ greatly in the criteria they specify for stability in thermal balance tests. Some specify a required temperature stabilization rate (the change in temperature per unit time, dT/dt), some specify that the final steady-state temperature be approached to within a specified difference, delta T , and some specify a combination of the two. The particular values for temperature stabilization rate and final temperature difference also vary greatly between specification documents. A one-size-fits-all temperature stabilization rate requirement does not yield consistent results for all test configurations because of differences in thermal mass and heat transfer to the environment. Applying a steady-state temperature difference requirement is problematic because the final test temperature is not accurately known a priori, especially for powered configurations. In the present work, a simplified, lumped-mass analysis has been used to explore the applicability of these criteria. A new, user-friendly, physics-based approach is developed that allows the thermal engineer to determine when an acceptable level of temperature stabilization has been achieved. The stabilization criterion can be predicted pre-test but must be refined during test to allow verification that the defined level of temperature stabilization has been achieved.

  16. Quality and shelf-life prediction for retail fresh hake (Merluccius merluccius).

    Science.gov (United States)

    García, Míriam R; Vilas, Carlos; Herrera, Juan R; Bernárdez, Marta; Balsa-Canto, Eva; Alonso, Antonio A

    2015-09-02

    Fish quality has a direct impact on market price and its accurate assessment and prediction are of main importance to set prices, increase competitiveness, resolve conflicts of interest and prevent food wastage due to conservative product shelf-life estimations. In this work we present a general methodology to derive predictive models of fish freshness under different storage conditions. The approach makes use of the theory of optimal experimental design, to maximize data information and in this way reduce the number of experiments. The resulting growth model for specific spoilage microorganisms in hake (Merluccius merluccius) is sufficiently informative to estimate quality sensory indexes under time-varying temperature profiles. In addition it incorporates quantitative information of the uncertainty induced by fish variability. The model has been employed to test the effect of factors such as fishing gear or evisceration, on fish spoilage and therefore fish quality. Results show no significant differences in terms of microbial growth between hake fished by long-line or bottom-set nets, within the implicit uncertainty of the model. Similar conclusions can be drawn for gutted and un-gutted hake along the experiment horizon. In addition, whenever there is the possibility to carry out the necessary experiments, this approach is sufficiently general to be used in other fish species and under different stress variables.

  17. Prediction and functional analysis of native disorder in proteins from the three kingdoms of life.

    Science.gov (United States)

    Ward, J J; Sodhi, J S; McGuffin, L J; Buxton, B F; Jones, D T

    2004-03-26

    An automatic method for recognizing natively disordered regions from amino acid sequence is described and benchmarked against predictors that were assessed at the latest critical assessment of techniques for protein structure prediction (CASP) experiment. The method attains a Wilcoxon score of 90.0, which represents a statistically significant improvement on the methods evaluated on the same targets at CASP. The classifier, DISOPRED2, was used to estimate the frequency of native disorder in several representative genomes from the three kingdoms of life. Putative, long (>30 residue) disordered segments are found to occur in 2.0% of archaean, 4.2% of eubacterial and 33.0% of eukaryotic proteins. The function of proteins with long predicted regions of disorder was investigated using the gene ontology annotations supplied with the Saccharomyces genome database. The analysis of the yeast proteome suggests that proteins containing disorder are often located in the cell nucleus and are involved in the regulation of transcription and cell signalling. The results also indicate that native disorder is associated with the molecular functions of kinase activity and nucleic acid binding.

  18. Quality of life related to health chronic kidney disease: Predictive importance of mood and somatic symptoms.

    Science.gov (United States)

    Perales Montilla, Carmen M; Duschek, Stefan; Reyes Del Paso, Gustavo A

    2016-01-01

    To compare the predictive capacity of self-reported somatic symptoms and mood (depression and anxiety) on health-related quality of life (HRQOL) in patients with chronic renal disease. Data were obtained from 52 patients undergoing haemodialysis. Measures included a) the SF-36 health survey, b) the somatic symptoms scale revised (ESS-R) and c) the hospital anxiety and depression scale (HADS). Multiple regression was the main method of statistical analysis. Patients exhibited HRQOL levels below normative values, with anxiety and depression prevalence at 36.5% and 27%, respectively. Mood was the strongest predictor of physical (β=-.624) and mental (β=-.709) HRQOL. Somatic symptoms were also associated with physical HRQOL, but their predictive value was weaker (β=-.270). These results indicate that mood is a superior predictor of the physical and mental components of HRQOL in patients compared with the number and severity of physical symptoms. The data underline the importance of assessing negative emotional states (depression and anxiety) in kidney patients as a basis for intervention, which may facilitate reduction of the impact of chronic renal disease on HRQOL. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  19. Damage-Induced Stresses and Remaining Service Life Predictions of Wire Ropes

    Directory of Open Access Journals (Sweden)

    Goran Vukelic

    2017-01-01

    Full Text Available Wire ropes in marine applications often encounter relatively fast and noticeable wear, a result of the fatigue to which they are exposed coupled with harsh operational conditions. This paper addresses some of the aspects of fatigue damage that occur in wire ropes. Using the finite element method, stress and fatigue analysis of three different design types (6 × 7, 7 × 7, 8 × 7 of wire rope is performed. The size of the wire rope cross-section area is varied in order to simulate the progressive damage of the wires so that consequential stress levels and remaining fatigue life can be numerically predicted. The aim was to provide a better understanding of the mechanical behavior of damaged wire ropes under various conditions, since an appropriate choice of wire rope design could then be made from engineering and economic points of view. Additionally, potential failures can be predicted, resulting in effective maintenance and the avoidance of potential risks of rope failure, especially important regarding economical and safety aspects of transportation in the marine industry.

  20. Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saxon, Aron R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lundstrom, Blake R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-25

    Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System: Preprint Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity and resistance as the battery degrades. Across 9 aging test conditions from 0oC to 55oC, the model predicts capacity fade with 1.4 percent RMS error and resistance growth with 15 percent RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.

  1. Analytical algorithms to quantify the uncertainty in remaining useful life prediction

    Science.gov (United States)

    Sankararaman, S.; Daigle, M.; Saxena, A.; Goebel, K.

    This paper investigates the use of analytical algorithms to quantify the uncertainty in the remaining useful life (RUL) estimate of components used in aerospace applications. The prediction of RUL is affected by several sources of uncertainty and it is important to systematically quantify their combined effect by computing the uncertainty in the RUL prediction in order to aid risk assessment, risk mitigation, and decision-making. While sampling-based algorithms have been conventionally used for quantifying the uncertainty in RUL, analytical algorithms are computationally cheaper and sometimes, are better suited for online decision-making. While exact analytical algorithms are available only for certain special cases (for e.g., linear models with Gaussian variables), effective approximations can be made using the first-order second moment method (FOSM), the first-order reliabilitymethod (FORM), and the inverse first-order reliabilitymethod (Inverse FORM). These methods can be used not only to calculate the entire probability distribution of RUL but also to obtain probability bounds on RUL. This paper explains these three methods in detail and illustrates them using the state-space model of a lithium-ion battery.

  2. Remaining useful life prediction based on the Wiener process for an aviation axial piston pump

    Institute of Scientific and Technical Information of China (English)

    Wang Xingjian; Lin Siru; Wang Shaoping; He Zhaomin; Zhang Chao

    2016-01-01

    An aviation hydraulic axial piston pump’s degradation from comprehensive wear is a typical gradual failure model. Accurate wear prediction is difficult as random and uncertain char-acteristics must be factored into the estimation. The internal wear status of the axial piston pump is characterized by the return oil flow based on fault mechanism analysis of the main frictional pairs in the pump. The performance degradation model is described by the Wiener process to predict the remaining useful life (RUL) of the pump. Maximum likelihood estimation (MLE) is performed by utilizing the expectation maximization (EM) algorithm to estimate the initial parameters of the Wiener process while recursive estimation is conducted utilizing the Kalman filter method to estimate the drift coefficient of the Wiener process. The RUL of the pump is then calculated accord-ing to the performance degradation model based on the Wiener process. Experimental results indi-cate that the return oil flow is a suitable characteristic for reflecting the internal wear status of the axial piston pump, and thus the Wiener process-based method may effectively predicate the RUL of the pump.

  3. Neither Basic Life Support knowledge nor self-efficacy are predictive of skills among dental students.

    Science.gov (United States)

    Mac Giolla Phadraig, C; Ho, J D; Guerin, S; Yeoh, Y L; Mohamed Medhat, M; Doody, K; Hwang, S; Hania, M; Boggs, S; Nolan, A; Nunn, J

    2017-08-01

    Basic life support (BLS) is considered a core competence for the graduating dentist. This study aimed to measure BLS knowledge, self-efficacy and skills of undergraduate dental students in Dublin. This study consisted of a cross-sectional survey measuring BLS knowledge and self-efficacy, accompanied by a directly observed BLS skills assessment in a subsample of respondents. Data were collected in January 2014. Bivariate correlations between descriptive and outcome variables (knowledge, self-efficacy and skills) were tested using Pearson's chi-square. We included knowledge and self-efficacy as predictor variables, along with other variables showing association, into a binary logistic regression model with BLS skills as the outcome measure. One hundred and thirty-five students participated. Almost all (n = 133, 98.5%) participants had BLS training within the last 2 years. One hundred and four (77%) felt that they were capable of providing effective BLS (self-efficacy), whilst only 46 (34.1%) scored >80% of knowledge items correct. Amongst the skills (n = 85) subsample, 38.8% (n = 33) were found to pass the BLS skills assessment. Controlling for gender, age and skills assessor, the regression model did not identify a predictive relationship between knowledge or self-efficacy and BLS skills. Neither knowledge nor self-efficacy was predictive of BLS skills. Dental students had low levels of knowledge and skills in BLS. Despite this, their confidence in their ability to perform BLS was high and did not predict actual competence. There is a need for additional hands-on training, focusing on self-efficacy and BLS skills, particularly the use of AED. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Use of Artificial Neural Network for Testing Effectiveness of Intelligent Computing Models for Predicting Shelf Life of Processed Cheese

    Directory of Open Access Journals (Sweden)

    GOYAL Kumar Gyanendra

    2012-10-01

    Full Text Available This paper presents the suitability of artificial neural network (ANN models for predicting the shelf life of processed cheese stored at 7-8ºC. Soluble nitrogen, pH; standard plate count, yeast & mould count, and spore count were input variables, and sensory score was output variable. Mean square error, root mean square error, coefficient of determination and Nash - sutcliffo coefficient were used in order to test the effectiveness of the developed ANN models. Excellent agreement was found between experimental results and these mathematical parameters, thus confirming that ANN models are very effective in predicting the shelf life of processed cheese.

  5. Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction

    Energy Technology Data Exchange (ETDEWEB)

    Geist, GA

    2003-09-16

    On July 22, 23, 24, 2003, three one day workshops were held in Gaithersburg, Maryland. Each was attended by about 30 computational biologists, mathematicians, and computer scientists who were experts in the respective workshop areas The first workshop discussed the data infrastructure needs for the Genomes to Life (GTL) program with the objective to identify gaps in the present GTL data infrastructure and define the GTL data infrastructure required for the success of the proposed GTL facilities. The second workshop discussed the modeling and simulation needs for the next phase of the GTL program and defined how these relate to the experimental data generated by genomics, proteomics, and metabolomics. The third workshop identified emerging technical challenges in computational protein structure prediction for DOE missions and outlining specific goals for the next phase of GTL. The workshops were attended by representatives from both OBER and OASCR. The invited experts at each of the workshops made short presentations on what they perceived as the key needs in the GTL data infrastructure, modeling and simulation, and structure prediction respectively. Each presentation was followed by a lively discussion by all the workshop attendees. The following findings and recommendations were derived from the three workshops. A seamless integration of GTL data spanning the entire range of genomics, proteomics, and metabolomics will be extremely challenging but it has to be treated as the first-class component of the GTL program to assure GTL's chances for success. High-throughput GTL facilities and ultrascale computing will make it possible to address the ultimate goal of modern biology: to achieve a fundamental, comprehensive, and systematic understanding of life. But first the GTL community needs to address the problem of the massive quantities and increased complexity of biological data produced by experiments and computations. Genome-scale collection, analysis

  6. Review of time-dependent fatigue behavior and life prediction for 2 1/4 Cr-1 Mo steel. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Booker, M.K.; Majumdar, S.

    1982-01-01

    Available data on creep-fatigue life and fracture behavior of 2 1/4 Cr-1 Mo steel are reviewed. Whereas creep-fatigue interaction is important for Type 304 stainless steel, oxidation effects appear to dominate the time-dependent fatigue behavior of 2 1/4 Cr-1 Mo steel. Four of the currently available predictive methods - the Linear Damage Rule, Frequency Separation Equation, Strain Range Partitioning Equation, and Damage Rate Equation - are evaluated for their predictive capability. Variations in the parameters for the various predictive methods with temperature, heat of material, heat treatment, and environment are investigated. Relative trends in the lives predicted by the various methods as functions of test duration, waveshape, etc., are discussed. The predictive methods will need modification in order to account for oxidation and aging effects in the 2 1/4 Cr-1 Mo steel. Future tests that will emphasize the difference between the various predictive methods are proposed.

  7. Profiling crop pollinators: life history traits predict habitat use and crop visitation by Mediterranean wild bees.

    Science.gov (United States)

    Pisanty, Gideon; Mandelik, Yael

    2015-04-01

    Wild pollinators, bees in particular, may greatly contribute to crop pollination and provide a safety net against declines in commercial pollinators. However, the identity, life history traits, and environmental sensitivities of main crop pollinator species.have received limited attention. These are crucial for predicting pollination services of different communities and for developing management practices that enhance crop pollinators. We sampled wild bees in three crop systems (almond, confection sunflower, and seed watermelon) in a mosaic Israeli Mediterranean landscape. Bees were sampled in field/orchard edges and interiors, and in seminatural scrub surrounding the fields/orchards. We also analyzed land cover at 50-2500 m radii around fields/orchards. We used this data to distinguish crop from non-crop pollinators based on a set of life history traits (nesting, lecty, sociality, body size) linked to habitat preference and crop visitation. Bee abundance and species richness decreased from the surrounding seminatural habitat to the field/orchard interior, especially across the seminatural habitat-field edge ecotone. Thus, although rich bee communities were found near fields, only small fractions crossed the ecotone and visited crop flowers in substantial numbers. The bee assemblage in agricultural fields/orchards and on crop flowers was dominated by ground-nesting bees of the tribe Halictini, which tend to nest within fields. Bees' habitat preferences were determined mainly by nesting guild, whereas crop visitation was determined mainly by sociality. Lecty and body size also affected both measures. The percentage of surrounding seminatural habitat at 250-2500 m radii had a positive effect on wild bee diversity in field edges, for all bee guilds, while at 50-100 m radii, only aboveground nesters were positively affected. In sum, we found that crop and non-crop pollinators are distinguished by behavioral and morphological traits. Hence, analysis of life

  8. Appreciation and Life Satisfaction: Does Appreciation Uniquely Predict Life Satisfaction above Gender, Coping Skills, Self-Esteem, and Positive Affectivity?

    Science.gov (United States)

    Halle, Joshua Solomon

    2015-01-01

    The primary purpose of this research was to examine whether appreciation explains variance in life satisfaction after controlling for gender, positive affectivity, self-esteem, and coping skills. Two hundred ninety-eight undergraduates went to the informed consent page of the online survey composed of the Appreciation Scale, the Satisfaction With…

  9. Childhood self-control predicts smoking throughout life: Evidence from 21,000 cohort study participants.

    Science.gov (United States)

    Daly, Michael; Egan, Mark; Quigley, Jody; Delaney, Liam; Baumeister, Roy F

    2016-11-01

    Low self-control has been linked with smoking, yet it remains unclear whether childhood self-control underlies the emergence of lifetime smoking patterns. We examined the contribution of childhood self-control to early smoking initiation and smoking across adulthood. 21,132 participants were drawn from 2 nationally representative cohort studies; the 1970 British Cohort Study (BCS) and the 1958 National Child Development Study (NCDS). Child self-control was teacher-rated at age 10 in the BCS and at ages 7 and 11 in the NCDS. Participants reported their smoking status and number of cigarettes smoked per day at 5 time-points in the BCS (ages 26-42) and 6 time-points in the NCDS (ages 23-55). Both studies controlled for socioeconomic background, cognitive ability, psychological distress, gender, and parental smoking; the NCDS also controlled for an extended set of background characteristics. Early self-control made a substantial graded contribution to (not) smoking throughout life. In adjusted regression models, a 1-SD increase in self-control predicted a 6.9 percentage point lower probability of smoking in the BCS, and this was replicated in the NCDS (5.2 point reduced risk). Adolescent smoking explained over half of the association between self-control and adult smoking. Childhood self-control was positively related to smoking cessation and negatively related to smoking initiation, relapse to smoking, and the number of cigarettes smoked in adulthood. This study provides strong evidence that low childhood self-control predicts an increased risk of smoking throughout adulthood and points to adolescent smoking as a key pathway through which this may occur. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  10. Accelerated Life Testing and Service Lifetime Prediction for PV Technologies in the Twenty-First Century

    Energy Technology Data Exchange (ETDEWEB)

    Czanderna, A. W.; Jorgensen, G. J.

    1999-07-13

    The purposes of this paper are to (1) discuss the necessity for conducting accelerated life testing (ALT) in the early stages of developing new photovoltaic (PV) technologies, (2) elucidate the crucial importance for combining ALT with real-time testing (RTT) in terrestrial environments for promising PV technologies for the 21st century, and (3) outline the essential steps for making a service lifetime prediction (SLP) for any PV technology. The specific objectives are to (a) illustrate the essential need for ALT of complete, encapsulated multilayer PV devices, (b) indicate the typical causes of degradation in PV stacks, (c) elucidate the complexity associated with quantifying the durability of the devices, (d) explain the major elements that constitute a generic SLP methodology, (e) show how the introduction of the SLP methodology in the early stages of new device development can reduce the cost of technology development, and (f) outline the procedure for combining the results of ALT and RTT, establishing degradation mechanisms, using sufficient numbers of samples, and applying the SLP methodology to produce a SLP for existing or new PV technologies.

  11. Tool life prediction under multi-cycle loading conditions: A feasibility study

    Directory of Open Access Journals (Sweden)

    Yuan Xi

    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 has not been addressed so far by metal forming researchers, and constant friction coefficient values are normally used in the FE simulations to represent the complex tribological nature at the contact interfaces. Meanwhile, most of the current FE simulations are single cycle, whereas most sheet metal forming operations are conducted as multi-cycle. 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.

  12. Quality of life among people with multiple sclerosis: Replication of a three-factor prediction model.

    Science.gov (United States)

    Bishop, Malachy; Rumrill, Phillip D; Roessler, Richard T

    2015-01-01

    This article presents a replication of Rumrill, Roessler, and Fitzgerald's 2004 analysis of a three-factor model of the impact of multiple sclerosis (MS) on quality of life (QOL). The three factors in the original model included illness-related, employment-related, and psychosocial adjustment factors. To test hypothesized relationships between QOL and illness-related, employment-related, and psychosocial variables using data from a survey of the employment concerns of Americans with MS (N = 1,839). An ex post facto, multiple correlational design was employed incorporating correlational and multiple regression analyses. QOL was positively related to educational level, employment status, job satisfaction, and job-match, and negatively related to number of symptoms, severity of symptoms, and perceived stress level. The three-factor model explained approximately 37 percent of the variance in QOL scores. The results of this replication confirm the continuing value of the three-factor model for predicting the QOL of adults with MS, and demonstrate the importance of medical, mental health, and vocational rehabilitation interventions and services in promoting QOL.

  13. A critical analysis of the Mises stress criterion used in frequency domain fatigue life prediction

    Directory of Open Access Journals (Sweden)

    Adam Niesłony

    2016-10-01

    Full Text Available Multiaxial fatigue failure criteria are formulated in time and frequency domain. The number of frequency domain criteria is rather small and the most popular one is the equivalent von Mises stress criterion. This criterion was elaborated by Preumont and Piefort on the basis of well-known von Mises stress concept, first proposed by Huber in 1907, and well accepted by the scientific community and engineers. It is important to know, that the criterion was developed to determine the yield stress and material effort under static load. Therefore the direct use of equivalent von Mises stress criterion for fatigue life prediction can lead to some incorrectness of theoretical and practical nature. In the present study four aspects were discussed: influence of the value of fatigue strength of tension and torsion, lack of parallelism of the SN curves, abnormal behaviour of the criterion under biaxial tensioncompression and influence of phase shift between particular stress state components. Information contained in this article will help to prevent improper use of this criterion and contributes to its better understanding

  14. Effect of Notch Location on Fatigue Life Prediction of Strength Mismatched HSLA Steel Weldments

    Institute of Scientific and Technical Information of China (English)

    S. Ravi; V. Balasubramanian; S. Nemat Nasser

    2004-01-01

    Welding of high strength low alloy steels (HSLA) involves usage of Iow, even and high strength filler materials (electrodes) than the parent material depending on the application of the welded structures and the availability of the filler material. In the present investigation, the fatigue crack growth behaviour of weld metal (WM) and heat affected zone (HAZ) regions of under matched (UM), equal matched (EM) and over matched (OM)joints has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. Shielded metal arc welding (SMAW) process has been used to fabricate the butt joints. Centre cracked tension (CCT) specimen has been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R=0). A method has been proposed to predict the fatigue life of HSLA steel welds using fracture mechanics approach by incorporating influences of mismatch ratio (MMR) and notch location.

  15. A new approach to predict the fish fillet shelf-life in presence of natural preservative agents

    Directory of Open Access Journals (Sweden)

    Alessandro Giufffrida

    2017-06-01

    Full Text Available Three data sets concerning the behaviour of spoilage flora of fillets treated with natural preservative substances (NPS were used to construct a new kind of mathematical predictive model. This model, unlike other ones, allows expressing the antibacterial effect of the NPS separately from the prediction of the growth rate. This approach, based on the introduction of a parameter into the predictive primary model, produced a good fitting of observed data and allowed characterising quantitatively the increase of shelf-life of fillets.

  16. Informed decision making about predictive DNA tests; arguments for more public visibility of personal deliberations about the good life.

    NARCIS (Netherlands)

    Boenink, Marianne; van der Burg, Simone

    2009-01-01

    Since its advent, predictive DNA testing has been perceived as a technology that may have considerable impact on the quality of people’s life. The decision whether or not to use this technology is up to the individual client. However, to enable well considered decision making both the negative as

  17. Informed decision making about predictive DNA tests; arguments for more public visibility of personal deliberations about the good life.

    NARCIS (Netherlands)

    Boenink, Marianne; van der Burg, Simone

    2009-01-01

    Since its advent, predictive DNA testing has been perceived as a technology that may have considerable impact on the quality of people’s life. The decision whether or not to use this technology is up to the individual client. However, to enable well considered decision making both the negative as we

  18. Health-related quality of life predicts long-term survival in patients with peripheral artery disease

    DEFF Research Database (Denmark)

    Issa, Samson M; Hoeks, Sanne E; Scholte op Reimer, Wilma J M;

    2010-01-01

    We examined whether health-related quality of life (HRQoL) predicts long-term survival in patients with peripheral artery disease (PAD) independent of established prognostic risk factors. In 2004, data on 711 consecutive patients with PAD undergoing vascular surgery were collected from 11 hospita...

  19. In silico prediction of brain exposure: drug free fraction, unbound brain to plasma concentration ratio and equilibrium half-life

    Science.gov (United States)

    Spreafico, Morena; Jacobson, Matthew P.

    2014-01-01

    The focus of CNS drug pharmacokinetics programs has recently shifted from determining the total concentrations in brain and blood to considering also unbound fractions and concentrations. Unfortunately, assessing unbound brain exposure experimentally requires demanding in vivo and in vitro studies. We propose a physical model, based on lipid binding and pH partitioning, to predict in silico the unbound volume of distribution in the brain. The model takes into account the partition of a drug into lipids, interstitial fluid and intracellular compartments of the brain. The results are in good agreement with the experimental data, suggesting that the contributions of lipid binding and pH partitioning are important in determining drug exposure in brain. The predicted values are used, together with predictions for plasma protein binding, as corrective terms in a second model to derive the unbound brain to plasma concentration ratio starting from experimental values of total concentration ratio. The calculated values of brain free fraction and passive permeability are also used to qualitatively determine the brain to plasma equilibration time in a model that shows promising results but is limited to a very small set of compounds. The models we propose are a step forward in understanding and predicting pharmacologically relevant exposure in brain starting from compounds’ chemical structure and neuropharmacokinetics, by using experimental total brain to plasma ratios, in silico calculated properties and simple physics-based approaches. The models can be used in central nervous system drug discovery programs for a fast and cheap assessment of unbound brain exposure. For existing compounds, the unbound ratios can be derived from experimental values of total brain to plasma ratios. For both existing and hypothetical compounds, the unbound volume of distribution due to lipid binding and pH partitioning can be calculated starting only from the chemical structure. PMID:23578025

  20. Learning from physics-based earthquake simulators: a minimal approach

    Science.gov (United States)

    Artale Harris, Pietro; Marzocchi, Warner; Melini, Daniele

    2017-04-01

    Physics-based earthquake simulators are aimed to generate synthetic seismic catalogs of arbitrary length, accounting for fault interaction, elastic rebound, realistic fault networks, and some simple earthquake nucleation process like rate and state friction. Through comparison of synthetic and real catalogs seismologists can get insights on the earthquake occurrence process. Moreover earthquake simulators can be used to to infer some aspects of the statistical behavior of earthquakes within the simulated region, by analyzing timescales not accessible through observations. The develoment of earthquake simulators is commonly led by the approach "the more physics, the better", pushing seismologists to go towards simulators more earth-like. However, despite the immediate attractiveness, we argue that this kind of approach makes more and more difficult to understand which physical parameters are really relevant to describe the features of the seismic catalog at which we are interested. For this reason, here we take an opposite minimal approach and analyze the behavior of a purposely simple earthquake simulator applied to a set of California faults. The idea is that a simple model may be more informative than a complex one for some specific scientific objectives, because it is more understandable. The model has three main components: the first one is a realistic tectonic setting, i.e., a fault dataset of California; the other two components are quantitative laws for earthquake generation on each single fault, and the Coulomb Failure Function for modeling fault interaction. The final goal of this work is twofold. On one hand, we aim to identify the minimum set of physical ingredients that can satisfactorily reproduce the features of the real seismic catalog, such as short-term seismic cluster, and to investigate on the hypothetical long-term behavior, and faults synchronization. On the other hand, we want to investigate the limits of predictability of the model itself.

  1. Development of a Novel Approach for Fatigue Life Prediction of Structural Materials

    Science.gov (United States)

    2008-12-01

    11] for Inconel 718 under a similar loading condition. A kink around a fatigue life of 3xl05 cycles was noticed in the shear strain-life curve from...observed on AISI 304 stainless steel [10], Inconel 718 [11], 1045 steel [12], and an aluminum alloy [13]. However, no kink in the strain-life curves

  2. STRUCTURAL SCALE LIFE PREDICTION OF AERO STRUCTURES EXPERIENCING COMBINED EXTREME ENVIRONMENTS

    Science.gov (United States)

    2017-07-01

    superiority of tomorrow’s USAF. These platforms experience long-duration, combined and intense, thermo-mechanical-acoustic loads over significant...analysts’ past experience , a heavy reliance on testing, and limited choices to tailor material attributes. 15. SUBJECT TERMS lifing, combined environment...6 Figure 3. Correlation Between Mean Life and Deviation of Mean life with the Addition of New Metallic Systems of

  3. A New Predictive Model Based on the ABC Optimized Multivariate Adaptive Regression Splines Approach for Predicting the Remaining Useful Life in Aircraft Engines

    Directory of Open Access Journals (Sweden)

    Paulino José García Nieto

    2016-05-01

    Full Text Available Remaining useful life (RUL estimation is considered as one of the most central points in the prognostics and health management (PHM. The present paper describes a nonlinear hybrid ABC–MARS-based model for the prediction of the remaining useful life of aircraft engines. Indeed, it is well-known that an accurate RUL estimation allows failure prevention in a more controllable way so that the effective maintenance can be carried out in appropriate time to correct impending faults. The proposed hybrid model combines multivariate adaptive regression splines (MARS, which have been successfully adopted for regression problems, with the artificial bee colony (ABC technique. This optimization technique involves parameter setting in the MARS training procedure, which significantly influences the regression accuracy. However, its use in reliability applications has not yet been widely explored. Bearing this in mind, remaining useful life values have been predicted here by using the hybrid ABC–MARS-based model from the remaining measured parameters (input variables for aircraft engines with success. A correlation coefficient equal to 0.92 was obtained when this hybrid ABC–MARS-based model was applied to experimental data. The agreement of this model with experimental data confirmed its good performance. The main advantage of this predictive model is that it does not require information about the previous operation states of the aircraft engine.

  4. A New Approach for Reliability Life Prediction of Rail Vehicle Axle by Considering Vibration Measurement

    Directory of Open Access Journals (Sweden)

    Meral Bayraktar

    2014-01-01

    Full Text Available The effect of vibration on the axle has been considered. Vibration measurements at different speeds have been performed on the axle of a running rail vehicle to figure out displacement, acceleration, time, and frequency response. Based on the experimental works, equivalent stress has been used to find out life of the axles for 90% and 10% reliability. Calculated life values of the rail vehicle axle have been compared with the real life data and it is found that the life of a vehicle axle taking into account the vibration effects is in good agreement with the real life of the axle.

  5. Prediction of Quality of Life of Non–Insulin-Dependent Diabetic Patients Based on Perceived Social Support

    Directory of Open Access Journals (Sweden)

    Hossein Shareh

    2012-04-01

    Full Text Available Background: The objective of this study was to predic quality of life based on perceived social support components in non–insulin-dependent diabetic patients.Materials and Method: Fifty patients with non–insulin-dependent diabetes mellitus from Al-Zahra diabetic center in Shiraz participated in a cross-sectional study via survey instrument. All subjects completed multidimensional scale of perceived social support (MSPSS and world health organization quality of life- brief (WHOQOL-BREF questionnaires. Results: On the basis of stepwise multiple regression analysis friends and family dimensions of perceived social support were the best predictors of the quality of life and its dimensions (p<0.01.Conclusion: Friends and family dimensions of perceived social support have significant contributions in predicting quality of life of patients with non–insulin-dependent diabetes mellitus.

  6. A Physics-Based Modeling Framework for Prognostic Studies

    Science.gov (United States)

    Kulkarni, Chetan S.

    2014-01-01

    Prognostics and Health Management (PHM) methodologies have emerged as one of the key enablers for achieving efficient system level maintenance as part of a busy operations schedule, and lowering overall life cycle costs. PHM is also emerging as a high-priority issue in critical applications, where the focus is on conducting fundamental research in the field of integrated systems health management. The term diagnostics relates to the ability to detect and isolate faults or failures in a system. Prognostics on the other hand is the process of predicting health condition and remaining useful life based on current state, previous conditions and future operating conditions. PHM methods combine sensing, data collection, interpretation of environmental, operational, and performance related parameters to indicate systems health under its actual application conditions. The development of prognostics methodologies for the electronics field has become more important as more electrical systems are being used to replace traditional systems in several applications in the aeronautics, maritime, and automotive fields. The development of prognostics methods for electronics presents several challenges due to the great variety of components used in a system, a continuous development of new electronics technologies, and a general lack of understanding of how electronics fail. Similarly with electric unmanned aerial vehicles, electrichybrid cars, and commercial passenger aircraft, we are witnessing a drastic increase in the usage of batteries to power vehicles. However, for battery-powered vehicles to operate at maximum efficiency and reliability, it becomes crucial to both monitor battery health and performance and to predict end of discharge (EOD) and end of useful life (EOL) events. We develop an electrochemistry-based model of Li-ion batteries that capture the significant electrochemical processes, are computationally efficient, capture the effects of aging, and are of suitable

  7. CMC Property Variability and Life Prediction Methods for Turbine Engine Component Application

    Science.gov (United States)

    Cheplak, Matthew L.

    2004-01-01

    The ever increasing need for lower density and higher temperature-capable materials for aircraft engines has led to the development of Ceramic Matrix Composites (CMCs). Today's aircraft engines operate with >3000"F gas temperatures at the entrance to the turbine section, but unless heavily cooled, metallic components cannot operate above approx.2000 F. CMCs attempt to push component capability to nearly 2700 F with much less cooling, which can help improve engine efficiency and performance in terms of better fuel efficiency, higher thrust, and reduced emissions. The NASA Glenn Research Center has been researching the benefits of the SiC/SiC CMC for engine applications. A CMC is made up of a matrix material, fibers, and an interphase, which is a protective coating over the fibers. There are several methods or architectures in which the orientation of the fibers can be manipulated to achieve a particular material property objective as well as a particular component geometric shape and size. The required shape manipulation can be a limiting factor in the design and performance of the component if there is a lack of bending capability of the fiber as making the fiber more flexible typically sacrifices strength and other fiber properties. Various analysis codes are available (pcGINA, CEMCAN) that can predict the effective Young's Moduli, thermal conductivities, coefficients of thermal expansion (CTE), and various other properties of a CMC. There are also various analysis codes (NASAlife) that can be used to predict the life of CMCs under expected engine service conditions. The objective of this summer study is to utilize and optimize these codes for examining the tradeoffs between CMC properties and the complex fiber architectures that will be needed for several different component designs. For example, for the pcGINA code, there are six variations of architecture available. Depending on which architecture is analyzed, the user is able to specify the fiber tow size, tow

  8. Does maternal oral health predict child oral health-related quality of life in adulthood?

    Directory of Open Access Journals (Sweden)

    Broadbent Jonathan M

    2011-07-01

    Full Text Available Abstract Background A parental/family history of poor oral health may influence the oral-health-related quality of life (OHRQOL of adults. Objectives To determine whether the oral health of mothers of young children can predict the OHRQOL of those same children when they reach adulthood. Methods Oral examination and interview data from the Dunedin Study's age-32 assessment, as well as maternal self-rated oral health data from the age-5 assessment were used. The main outcome measure was study members' short-form Oral Health Impact Profile (OHIP-14 at age 32. Analyses involved 827 individuals (81.5% of the surviving cohort dentally examined at both ages, who also completed the OHIP-14 questionnaire at age 32, and whose mothers were interviewed at the age-5 assessment. Results There was a consistent gradient of relative risk across the categories of maternal self-rated oral health status at the age-5 assessment for having one or more impacts in the overall OHIP-14 scale, whereby risk was greatest among the study members whose mothers rated their oral health as "poor/edentulous", and lowest among those with an "excellent/fairly good" rating. In addition, there was a gradient in the age-32 mean OHIP-14 score, and in the mean number of OHIP-14 impacts at age 32 across the categories of maternal self-rated oral health status. The higher risk of having one or more impacts in the psychological discomfort subscale, when mother rated her oral health as "poor/edentulous", was statistically significant. Conclusions These data suggest that maternal self-rated oral health when a child is young has a bearing on that child's OHRQOL almost three decades later. The adult offspring of mothers with poor self-rated oral health had poorer OHRQOL outcomes, particularly in the psychological discomfort subscale.

  9. Quality of life predicts outcome in a heart failure disease management program.

    LENUS (Irish Health Repository)

    O'Loughlin, Christina

    2012-02-01

    BACKGROUND: Chronic heart failure (HF) is associated with a poor Health Related Quality of Life (HRQoL). HRQoL has been shown to be a predictor of HF outcomes however, variability in the study designs make it difficult to apply these findings to a clinical setting. The aim of this study was to establish if HRQoL is a predictor of long-term mortality and morbidity in HF patients followed-up in a disease management program (DMP) and if a HRQoL instrument could be applied to aid in identifying high-risk patients within a clinical context. METHODS: This is a retrospective analysis of HF patients attending a DMP with 18+\\/-9 months follow-up. Clinical and biochemical parameters were recorded on discharge from index HF admission and HRQoL measures were recorded at 2 weeks post index admission. RESULTS: 225 patients were enrolled into the study (mean age=69+\\/-12 years, male=61%, and 78%=systolic HF). In multivariable analysis, all dimensions of HRQoL (measured by the Minnesota Living with HF Questionnaire) were independent predictors of both mortality and readmissions particularly in patients <80 years. A significant interaction between HRQoL and age (Total((HRQoL))age: p<0.001) indicated that the association of HRQoL with outcomes diminished as age increased. CONCLUSIONS: These data demonstrate that HRQoL is a predictor of outcome in HF patients managed in a DMP. Younger patients (<65 years) with a Total HRQoL score of > or =50 are at high risk of an adverse outcome. In older patients > or =80 years HRQoL is not useful in predicting outcome.

  10. Predictive factors for body weight loss and its impact on quality of life following gastrectomy.

    Science.gov (United States)

    Tanabe, Kazuaki; Takahashi, Masazumi; Urushihara, Takashi; Nakamura, Yoichi; Yamada, Makoto; Lee, Sang-Woong; Tanaka, Shinnosuke; Miki, Akira; Ikeda, Masami; Nakada, Koji

    2017-07-14

    To determine the predictive factors and impact of body weight loss on postgastrectomy quality of life (QOL). We applied the newly developed integrated questionnaire postgastrectomy syndrome assessment scale-45, which consists of 45 items including those from the Short Form-8 and Gastrointestinal Symptom Rating Scale instruments, in addition to 22 newly selected items. Between July 2009 and December 2010, completed questionnaires were received from 2520 patients with curative resection at 1 year or more after having undergone one of six types of gastrectomy for Stage I gastric cancer at one of 52 participating institutions. Of those, we analyzed 1777 eligible questionnaires from patients who underwent total gastrectomy with Roux-en-Y procedure (TGRY) or distal gastrectomy with Billroth-I (DGBI) or Roux-en-Y (DGRY) procedures. A total of 393, 475 and 909 patients underwent TGRY, DGRY, and DGBI, respectively. The mean age of patients was 62.1 ± 9.2 years. The mean time interval between surgery and retrieval of the questionnaires was 37.0 ± 26.8 mo. On multiple regression analysis, higher preoperative body mass index, total gastrectomy, and female sex, in that order, were independent predictors of greater body weight loss after gastrectomy. There was a significant difference in the degree of weight loss (P 25 kg/m(2)). Multiple linear regression analysis identified lower postoperative body mass index, rather than greater body weight loss postoperatively, as a certain factor for worse QOL (P weight after gastrectomy, the impact of body weight loss on QOL is unexpectedly small.

  11. Predicting quality of life in multiple sclerosis: accounting for physical disability, fatigue, cognition, mood disorder, personality, and behavior change.

    Science.gov (United States)

    Benedict, Ralph H B; Wahlig, Elizabeth; Bakshi, Rohit; Fishman, Inna; Munschauer, Frederick; Zivadinov, Robert; Weinstock-Guttman, Bianca

    2005-04-15

    Health-related quality of life (HQOL) is poor in multiple sclerosis (MS) but the clinical precipitants of the problem are not well understood. Previous correlative studies demonstrated relationships between various clinical parameters and diminished HQOL in MS. Unfortunately, these studies failed to account for multiple predictors in the same analysis. We endeavored to determine what clinical parameters account for most variance in predicting HQOL, and employability, while accounting for disease course, physical disability, fatigue, cognition, mood disorder, personality, and behavior disorder. In 120 MS patients, we measured HQOL (MS Quality of Life-54) and vocational status (employed vs. disabled) and then conducted detailed clinical testing. Data were analyzed by linear and logistic regression methods. MS patients reported lower HQOL (pPhysical HQOL was predicted by fatigue, depression, and physical disability. Mental HQOL was associated with only depression and fatigue. In contrast, vocational status was predicted by three cognitive tests, conscientiousness, and disease duration (p<0.05). Thus, for the first time, we predicted HQOL in MS while accounting for measures from these many clinical domains. We conclude that self-report HQOL indices are most strongly predicted by measures of depression, whereas vocational status is predicted primarily by objective measures of cognitive function. The findings highlight core clinical problems that merit early identification and further research regarding the development of effective treatment.

  12. A Novel Creep-Fatigue Life Prediction Model for P92 Steel on the Basis of Cyclic Strain Energy Density

    Science.gov (United States)

    Ji, Dongmei; Ren, Jianxing; Zhang, Lai-Chang

    2016-09-01

    A novel creep-fatigue life prediction model was deduced based on an expression of the strain energy density in this study. In order to obtain the expression of the strain energy density, the load-controlled creep-fatigue (CF) tests of P92 steel at 873 K were carried out. Cyclic strain of P92 steel under CF load was divided into elastic strain, applying and unloading plastic strain, creep strain, and anelastic strain. Analysis of cyclic strain indicates that the damage process of P92 steel under CF load consists of three stages, similar to pure creep. According to the characteristics of the strains above, an expression was defined to describe the strain energy density for each cycle. The strain energy density at stable stage is inversely proportional to the total strain energy density dissipated by P92 steel. However, the total strain energy densities under different test conditions are proportional to the fatigue life. Therefore, the expression of the strain energy density at stable stage was chosen to predict the fatigue life. The CF experimental data on P92 steel were employed to verify the rationality of the novel model. The model obtained from the load-controlled CF test of P92 steel with short holding time could predict the fatigue life of P92 steel with long holding time.

  13. A study on the fatigue life prediction of the various gas-welded joints using a probabilistic statistics technique

    Science.gov (United States)

    Baek, Seung Yeb; Bae, Dong Ho

    2011-02-01

    Gas welding is a very important and useful technology in the fabrication of railroad cars and commercial vehicle structures. However, since the fatigue strength of gas-welded joints is considerably lower than that of the base of material due to stress concentration at the weld, the fatigue strength assessment of gas-welded joints is very important for the reliability and durability of railroad cars and establishment of criteria for long-life fatigue design. In this study, after evaluating the fatigue strength using a simulated specimen that satisfies not only the structural characteristics but also the mechanical condition of the actual structure, the fatigue design criteria are determined and applied to the fatigue design of the gas welded body structure. To save time and cost for the fatigue design, we investigated an accelerated life-prediction using a probabilistic statistics technique based on the theory of statistical reliability. The (Δσ a )R-Nf relationship was obtained from actual fatigue test data, including welding residual stress. On the basis of these results, the (Δσa)R-(Nf)ALP relationship that was derived from statistical probability analysis was compared with the actual fatigue test data. Therefore, it is expected that the accelerated life prediction will provide a useful method of determining the criteria for fatigue design and predicting a specific target life.

  14. A Novel Creep-Fatigue Life Prediction Model for P92 Steel on the Basis of Cyclic Strain Energy Density

    Science.gov (United States)

    Ji, Dongmei; Ren, Jianxing; Zhang, Lai-Chang

    2016-11-01

    A novel creep-fatigue life prediction model was deduced based on an expression of the strain energy density in this study. In order to obtain the expression of the strain energy density, the load-controlled creep-fatigue (CF) tests of P92 steel at 873 K were carried out. Cyclic strain of P92 steel under CF load was divided into elastic strain, applying and unloading plastic strain, creep strain, and anelastic strain. Analysis of cyclic strain indicates that the damage process of P92 steel under CF load consists of three stages, similar to pure creep. According to the characteristics of the strains above, an expression was defined to describe the strain energy density for each cycle. The strain energy density at stable stage is inversely proportional to the total strain energy density dissipated by P92 steel. However, the total strain energy densities under different test conditions are proportional to the fatigue life. Therefore, the expression of the strain energy density at stable stage was chosen to predict the fatigue life. The CF experimental data on P92 steel were employed to verify the rationality of the novel model. The model obtained from the load-controlled CF test of P92 steel with short holding time could predict the fatigue life of P92 steel with long holding time.

  15. Physics-based statistical model and simulation method of RF propagation in urban environments

    Science.gov (United States)

    Pao, Hsueh-Yuan; Dvorak, Steven L.

    2010-09-14

    A physics-based statistical model and simulation/modeling method and system of electromagnetic wave propagation (wireless communication) in urban environments. In particular, the model is a computationally efficient close-formed parametric model of RF propagation in an urban environment which is extracted from a physics-based statistical wireless channel simulation method and system. The simulation divides the complex urban environment into a network of interconnected urban canyon waveguides which can be analyzed individually; calculates spectral coefficients of modal fields in the waveguides excited by the propagation using a database of statistical impedance boundary conditions which incorporates the complexity of building walls in the propagation model; determines statistical parameters of the calculated modal fields; and determines a parametric propagation model based on the statistical parameters of the calculated modal fields from which predictions of communications capability may be made.

  16. The role of brain/behavioural systems in prediction of quality of life and coping strategies in cancer patients

    Directory of Open Access Journals (Sweden)

    Shala Jangi Goujeh Biglou

    2014-03-01

    Full Text Available Background: It seems that individual differences in personality characteristics are implicated in the incidence and progress of physical diseases and socio-psychological consequences. However, there are a few studies about the role of personality in the prediction of socio-psychological consequences of cancer. The aim of this research was to survey the role of personality in the prediction of socio-psychosocial factors: quality of life and coping strategies. Methods: This research was a descriptive-correlational study in which the sample included fifty cancer patients who were selected through convenience sampling method. To assess the personality differences, quality of life and coping strategies, the Carver and White (1994 BIS/BAS Scales, SF-12 Health Survey and Coping Inventory for Stressful Situation (CISS were used, respectively. The data were analysed by SPSS software using Pearson correlation coefficient and stepwise regression. Results: The findings showed that Both BIS and BAS systems could predict the quality of life (P<0.001, BIS system could explain the emotion-oriented coping strategy (P<0.05 and avoidance-oriented coping stratesy (P<0.01 and BAS system could explain the problem-oriented coping strategy (P<0.001. Conclusion: The findings of this study showed that brain/behavioural systems can predict the quality of life and coping strategies in cancer patients. The identification of these systems in cancer patients can help recognize the persons that are under the risk of poor quality of life or have a higher chance of using inconsistent coping strategies, and execute preventive measures about them.

  17. Interior Fracture Mechanism Analysis and Fatigue Life Prediction of Surface-Hardened Gear Steel under Axial Loading

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-10-01

    Full Text Available The interior defect-induced fracture of surface-hardened metallic materials in the long life region has become a key issue on engineering design. In the present study, the axial loading test with fully reversed condition was performed to examine the fatigue property of a surface-carburized low alloy gear steel in the long life region. Results show that this steel represents the duplex S-N (stress-number of cycles characteristics without conventional fatigue limit related to 107 cycles. Fatigue cracks are all originated from the interior inclusions in the matrix region due to the inhabitation effect of carburized layer. The inclusion induced fracture with fisheye occurs in the short life region below 5 × 105 cycles, whereas the inclusion induced fracture with fine granular area (FGA and fisheye occurs in the long life region beyond 106 cycles. The stress intensity factor range at the front of FGA can be regarded as the threshold value controlling stable growth of interior long crack. The evaluated maximum inclusion size in the effective damage volume of specimen is about 27.29 μm. Considering the size relationships between fisheye and FGA, and inclusion, the developed life prediction method involving crack growth can be acceptable on the basis of the good agreement between the predicted and experimental results.

  18. Interior Fracture Mechanism Analysis and Fatigue Life Prediction of Surface-Hardened Gear Steel under Axial Loading.

    Science.gov (United States)

    Li, Wei; Deng, Hailong; Liu, Pengfei

    2016-10-18

    The interior defect-induced fracture of surface-hardened metallic materials in the long life region has become a key issue on engineering design. In the present study, the axial loading test with fully reversed condition was performed to examine the fatigue property of a surface-carburized low alloy gear steel in the long life region. Results show that this steel represents the duplex S-N (stress-number of cycles) characteristics without conventional fatigue limit related to 10⁷ cycles. Fatigue cracks are all originated from the interior inclusions in the matrix region due to the inhabitation effect of carburized layer. The inclusion induced fracture with fisheye occurs in the short life region below 5 × 10⁵ cycles, whereas the inclusion induced fracture with fine granular area (FGA) and fisheye occurs in the long life region beyond 10⁶ cycles. The stress intensity factor range at the front of FGA can be regarded as the threshold value controlling stable growth of interior long crack. The evaluated maximum inclusion size in the effective damage volume of specimen is about 27.29 μm. Considering the size relationships between fisheye and FGA, and inclusion, the developed life prediction method involving crack growth can be acceptable on the basis of the good agreement between the predicted and experimental results.

  19. A Bayesian least-squares support vector machine method for predicting the remaining useful life of a microwave component

    Directory of Open Access Journals (Sweden)

    Fuqiang Sun

    2017-01-01

    Full Text Available Rapid and accurate lifetime prediction of critical components in a system is important to maintaining the system’s reliable operation. To this end, many lifetime prediction methods have been developed to handle various failure-related data collected in different situations. Among these methods, machine learning and Bayesian updating are the most popular ones. In this article, a Bayesian least-squares support vector machine method that combines least-squares support vector machine with Bayesian inference is developed for predicting the remaining useful life of a microwave component. A degradation model describing the change in the component’s power gain over time is developed, and the point and interval remaining useful life estimates are obtained considering a predefined failure threshold. In our case study, the radial basis function neural network approach is also implemented for comparison purposes. The results indicate that the Bayesian least-squares support vector machine method is more precise and stable in predicting the remaining useful life of this type of components.

  20. Nonlinear-drifted Brownian motion with multiple hidden states for remaining useful life prediction of rechargeable batteries

    Science.gov (United States)

    Wang, Dong; Zhao, Yang; Yang, Fangfang; Tsui, Kwok-Leung

    2017-09-01

    Brownian motion with adaptive drift has attracted much attention in prognostics because its first hitting time is highly relevant to remaining useful life prediction and it follows the inverse Gaussian distribution. Besides linear degradation modeling, nonlinear-drifted Brownian motion has been developed to model nonlinear degradation. Moreover, the first hitting time distribution of the nonlinear-drifted Brownian motion has been approximated by time-space transformation. In the previous studies, the drift coefficient is the only hidden state used in state space modeling of the nonlinear-drifted Brownian motion. Besides the drift coefficient, parameters of a nonlinear function used in the nonlinear-drifted Brownian motion should be treated as additional hidden states of state space modeling to make the nonlinear-drifted Brownian motion more flexible. In this paper, a prognostic method based on nonlinear-drifted Brownian motion with multiple hidden states is proposed and then it is applied to predict remaining useful life of rechargeable batteries. 26 sets of rechargeable battery degradation samples are analyzed to validate the effectiveness of the proposed prognostic method. Moreover, some comparisons with a standard particle filter based prognostic method, a spherical cubature particle filter based prognostic method and two classic Bayesian prognostic methods are conducted to highlight the superiority of the proposed prognostic method. Results show that the proposed prognostic method has lower average prediction errors than the particle filter based prognostic methods and the classic Bayesian prognostic methods for battery remaining useful life prediction.

  1. PREFACE: Physics-Based Mathematical Models for Nanotechnology

    Science.gov (United States)

    Voon, Lok C. Lew Yan; Melnik, Roderick; Willatzen, Morten

    2008-03-01

    stain-resistant clothing, but with thousands more anticipated. The focus of this interdisciplinary workshop was on determining what kind of new theoretical and computational tools will be needed to advance the science and engineering of nanomaterials and nanostructures. Thanks to the stimulating environment of the BIRS, participants of the workshop had plenty of opportunity to exchange new ideas on one of the main topics of this workshop—physics-based mathematical models for the description of low-dimensional semiconductor nanostructures (LDSNs) that are becoming increasingly important in technological innovations. The main objective of the workshop was to bring together some of the world leading experts in the field from each of the key research communities working on different aspects of LDSNs in order to (a) summarize the state-of-the-art models and computational techniques for modeling LDSNs, (b) identify critical problems of major importance that require solution and prioritize them, (c) analyze feasibility of existing mathematical and computational methodologies for the solution of some such problems, and (d) use some of the workshop working sessions to explore promising approaches in addressing identified challenges. With the possibility of growing practically any shape and size of heterostructures, it becomes essential to understand the mathematical properties of quantum-confined structures including properties of bulk states, interface states, and surface states as a function of shape, size, and internal strain. This workshop put strong emphasis on discussions of the new mathematics needed in nanotechnology especially in relation to geometry and material-combination optimization of device properties such as electronic, optical, and magnetic properties. The problems that were addressed at this meeting are of immense importance in determining such quantum-mechanical properties and the group of invited participants covered very well all the relevant disciplines

  2. Predictions for fatigue crack growth life of cracked pipes and pipe welds using RMS SIF approach and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Punit, E-mail: punit@barc.gov.in [Bhabha Atomic Research Centre, Department of Atomic Energy, Maharashtra, Mumbai 400 085 (India); Singh, P.K.; Bhasin, Vivek; Vaze, K.K.; Ghosh, A.K. [Bhabha Atomic Research Centre, Department of Atomic Energy, Maharashtra, Mumbai 400 085 (India); Pukazhendhi, D.M.; Gandhi, P.; Raghava, G. [Structural Engineering Research Centre, Chennai 600 113 (India)

    2011-10-15

    The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined for pipe (base) and pipe weld materials by using Compact Tension (CT) specimens machined from the actual pipe/pipe weld. Analyses have been carried out to predict the fatigue crack growth life of the austenitic stainless steel pipes/pipes welds having part through cracks on the outer surface. In the analyses, Stress Intensity Factors (K) have been evaluated through two different schemes. The first scheme considers the 'K' evaluations at two points of the crack front i.e. maximum crack depth and crack tip at the outer surface. The second scheme accounts for the area averaged root mean square stress intensity factor (K{sub RMS}) at deepest and surface points. Crack growth and the crack shape with loading cycles have been evaluated. In order to validate the analytical procedure/results, experiments have been carried out on full scale pipe and pipe welds with part through circumferential crack. Fatigue crack growth life evaluated using both schemes have been compared with experimental results. Use of stress intensity factor (K{sub RMS}) evaluated using second scheme gives better fatigue crack growth life prediction compared to that of first scheme. Fatigue crack growth in pipe weld (Gas Tungsten Arc Welding) can be predicted well using Paris constants of base material but prediction is non-conservative for pipe weld (Shielded Metal Arc Welding). Further, predictions using fatigue crack growth rate curve of ASME produces conservative results for pipe and GTAW pipe welds and comparable results for SMAW pipe welds. - Highlights: > Predicting fatigue crack growth of Austenitic Stainless Steel pipes and pipe welds. > Use of RMS-SIF and

  3. Sensitivity analysis and calibration of a dynamic physically based slope stability model

    Science.gov (United States)

    Zieher, Thomas; Rutzinger, Martin; Schneider-Muntau, Barbara; Perzl, Frank; Leidinger, David; Formayer, Herbert; Geitner, Clemens

    2017-06-01

    Physically based modelling of slope stability on a catchment scale is still a challenging task. When applying a physically based model on such a scale (1 : 10 000 to 1 : 50 000), parameters with a high impact on the model result should be calibrated to account for (i) the spatial variability of parameter values, (ii) shortcomings of the selected model, (iii) uncertainties of laboratory tests and field measurements or (iv) parameters that cannot be derived experimentally or measured in the field (e.g. calibration constants). While systematic parameter calibration is a common task in hydrological modelling, this is rarely done using physically based slope stability models. In the present study a dynamic, physically based, coupled hydrological-geomechanical slope stability model is calibrated based on a limited number of laboratory tests and a detailed multitemporal shallow landslide inventory covering two landslide-triggering rainfall events in the Laternser valley, Vorarlberg (Austria). Sensitive parameters are identified based on a local one-at-a-time sensitivity analysis. These parameters (hydraulic conductivity, specific storage, angle of internal friction for effective stress, cohesion for effective stress) are systematically sampled and calibrated for a landslide-triggering rainfall event in August 2005. The identified model ensemble, including 25 behavioural model runs with the highest portion of correctly predicted landslides and non-landslides, is then validated with another landslide-triggering rainfall event in May 1999. The identified model ensemble correctly predicts the location and the supposed triggering timing of 73.0 % of the observed landslides triggered in August 2005 and 91.5 % of the observed landslides triggered in May 1999. Results of the model ensemble driven with raised precipitation input reveal a slight increase in areas potentially affected by slope failure. At the same time, the peak run-off increases more markedly, suggesting that

  4. A Multiaxial Low Cycle Fatigue Life Prediction Model for Both Proportional and Non-proportional Loading Conditions

    Science.gov (United States)

    Paul, Surajit Kumar

    2014-09-01

    This paper has presented a life prediction model in the field of multiaxial low-cycle fatigue. The proposed model is generally applied for constant amplitude multiaxial proportional and non-proportional loading. Depending upon applied strain path the equivalent strain varies within a cycle. Equivalent average strain amplitude is considered as fatigue damage parameter in the proposed model. The model has requirement of only two material constants and no other tuning parameters. The model is examined by the proportional and non-proportional low-cycle fatigue life experimental data for eight different types of materials. The model is successfully correlated with multiaxial fatigue lives of eight different materials.

  5. The choice for breast cancer surgery: can women accurately predict postoperative quality of life and disease-related stigma?

    Science.gov (United States)

    Waljee, Jennifer F; Ubel, Peter A; Atisha, Dunya M; Hu, Emily S; Alderman, Amy K

    2011-09-01

    To make an informed choice, breast cancer patients facing surgery must imagine the effect of surgery on their future life experiences. However, the accuracy of patient predictions of postoperative quality of life (QoL) and disease-related stigma is not well understood. Four groups of breast cancer patients at the University of Michigan Medical Center were surveyed by mail and interview (response rate 76.3%): (1) preoperative (N = 59), (2) mastectomy (N = 146), (3) mastectomy with reconstruction (N = 250), and (4) breast conservation (N = 705). Subjects rated their QoL (1 = lowest, 100 = highest) and stigma (1 = lowest, 5 = highest) and estimated QoL and stigma associated with mastectomy alone, mastectomy with reconstruction, and breast conserving surgery (BCS). Mean scores were compared using linear regression controlling for age, race, partnered status, and income. Preoperatively, women inaccurately predicted postoperative QoL and stigma for all surgical options, particularly for mastectomy. Preoperative patients underestimated the postoperative QoL for mastectomy alone (predicted: 56.8 vs actual: 83.7; P mastectomy following reconstruction (predicted: 73.4 vs actual: 83.9; P mastectomy (predicted: 3.25 vs actual: 2.43; P women overestimated stigma related to mastectomy with reconstruction (predicted: 2.54 vs actual: 2.03; P < .001) and BCS (predicted: 1.90 vs actual: 1.76; P < .001). Predicting QoL and stigma following breast cancer surgery is challenging for patients facing a diagnosis for surgery. Identifying strategies to better inform patients of surgical outcomes can improve the decision-making process.

  6. The Role of Social Relationships in Predicting Loneliness: The National Social Life, Health, and Aging Project

    Science.gov (United States)

    Shiovitz-Ezra, Sharon; Leitsch, Sara A.

    2010-01-01

    The authors explore associations between objective and subjective social network characteristics and loneliness in later life, using data from the National Social Life, Health, and Aging Project, a nationally representative sample of individuals ages 57 to 85 in the United States. Hierarchical linear regression was used to examine the associations…

  7. Predicting the natural mortality of marine fish from life history characteristics

    DEFF Research Database (Denmark)

    Gislason, Henrik

    For fish much of the life history is determined by body size. Body size and asymptotic size significantly influences important life history processes such as growth, maturity, egg production, and natural mortality. Futhermore, for a population to persist, offspring must be able to replace their p...... of the species, and with the von Bertalanffy growth parameter K....

  8. Your Face is Your Fortune: Does Adolescent Attractiveness Predict Intimate Relationships Later in Life?

    Science.gov (United States)

    Karraker, Amelia; Sicinski, Kamil; Moynihan, Donald

    2017-01-01

    A growing literature documents the importance of physical attractiveness in young and middle adulthood for romantic, marital, and sexual relationships, but little is known about how attractiveness in adolescence matters to intimate relationships in later life. We ask: does attractiveness early in life convey ongoing benefits late in life, or do such benefits erode over time? We use multivariate regression models and more than 50 years of data from the Wisconsin Longitudinal Study to examine the connections between adolescent physical attractiveness and intimate relationships (i.e., sexual activity and access to potential sexual partners) in later life. We find that adolescent attractiveness facilitates sexual activity in later life. This relationship is largely driven by attractiveness increasing the probability of having access to potential sexual partners. However, attractiveness is not related to sexual activity among married couples, even after controlling for marital duration. Men, those in good health, and wealthier individuals are also more likely to engage in several facets of intimate relationships. These findings highlight the importance of relationship context for later life sexual activity and begin to explicate the pathways through which factors across the life course-particularly attractiveness-influence sexual activity in later life. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Predicting the natural mortality of marine fish from life history characteristics

    DEFF Research Database (Denmark)

    Gislason, Henrik

    For fish much of the life history is determined by body size. Body size and asymptotic size significantly influences important life history processes such as growth, maturity, egg production, and natural mortality. Futhermore, for a population to persist, offspring must be able to replace...

  10. Early Caries Predicts Low Oral Health-Related Quality of Life at a Later Age

    NARCIS (Netherlands)

    Kragt, L.; Tas, J.T. van der; Moll, H.A.; Elfrink, M.E.; Jaddoe, V.W.; Wolvius, E.B.; Ongkosuwito, E.M.

    2016-01-01

    Oral health-related quality of life (OHRQOL) is the perceived impact of one's own oral health on daily life. Oral diseases influence children's OHRQOL directly, but OHRQOL might also be related to oral health experiences from the past. We investigate the relation between dental caries at the age of

  11. Central Nervous System Based Computing Models for Shelf Life Prediction of Soft Mouth Melting Milk Cakes

    Directory of Open Access Journals (Sweden)

    Gyanendra Kumar Goyal

    2012-04-01

    Full Text Available This paper presents the latency and potential of central nervous system based system intelligent computer engineering system for detecting shelf life of soft mouth melting milk cakes stored at 10o C. Soft mouth melting milk cakes are exquisite sweetmeat cuisine made out of heat and acid thickened solidified sweetened milk. In today’s highly competitive market consumers look for good quality food products. Shelf life is a good and accurate indicator to the food quality and safety. To achieve good quality of food products, detection of shelf life is important. Central nervous system based intelligent computing model was developed which detected 19.82 days shelf life, as against 21 days experimental shelf life.

  12. An integrated Gaussian process regression for prediction of remaining useful life of slow speed bearings based on acoustic emission

    Science.gov (United States)

    Aye, S. A.; Heyns, P. S.

    2017-02-01

    This paper proposes an optimal Gaussian process regression (GPR) for the prediction of remaining useful life (RUL) of slow speed bearings based on a novel degradation assessment index obtained from acoustic emission signal. The optimal GPR is obtained from an integration or combination of existing simple mean and covariance functions in order to capture the observed trend of the bearing degradation as well the irregularities in the data. The resulting integrated GPR model provides an excellent fit to the data and improves over the simple GPR models that are based on simple mean and covariance functions. In addition, it achieves a low percentage error prediction of the remaining useful life of slow speed bearings. These findings are robust under varying operating conditions such as loading and speed and can be applied to nonlinear and nonstationary machine response signals useful for effective preventive machine maintenance purposes.

  13. Health-related quality of life and its predictive role for analgesic effect in patients with painful polyneuropathy

    DEFF Research Database (Denmark)

    Otto, Marit; Bach, Flemming W; Jensen, Troels S

    2007-01-01

    Painful polyneuropathy is a common neuropathic pain condition. The present study describes health-related quality of life (HRQL) in a sample of patients with painful polyneuropathy of different origin and the possible predictive role of HRQL for analgesic effect. Ninety-three patients with a diag......Painful polyneuropathy is a common neuropathic pain condition. The present study describes health-related quality of life (HRQL) in a sample of patients with painful polyneuropathy of different origin and the possible predictive role of HRQL for analgesic effect. Ninety-three patients...... questionnaire (SF-36) after a drug-free baseline period and at the end of each treatment period. At baseline, all eight SF-36 scores were lower than in the normal population. No significant differences were found between SF-36 scales during placebo and treatment with valproic acid and St. John's wort. Those two...

  14. Long-term Creep Life Prediction and Its Reliability on HAZ Failure Data of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo Gon; Jang, Jin Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Jae Young [Pukyong National University, Busan (Korea, Republic of)

    2015-10-15

    Long-term creep life prediction on Grade 91 HAZ failure data was performed by LM parameter, and its reliability was successfully demonstrated using SCRI model based on Z-parameter. To improve the creep life prediction at the low stress range of high temperature range, the master curve with a 'sinh' function was newly proposed. By Monte-Carlo simulation, reliability assessment was made using the chosen service temperature and stress conditions. carbide/nitride forming elements such as V and Nb along with controlled addition of N in the plain 9Cr. 1Mo steel, offers a good combination of high creep strength and ductility over prolonged exposures at elevated temperatures. The choice of Gr. 91 steel for sodium-cooled fast reactor (SFR) applications is guided by its low thermal expansion coefficient and high resistance to stress corrosion cracking in water-steam systems compared to austenitic stainless steels.

  15. V-Notched Bar Creep Life Prediction: GH3536 Ni-Based Superalloy Under Multiaxial Stress State

    Science.gov (United States)

    Zhang, D. X.; Wang, J. P.; Wen, Z. X.; Liu, D. S.; Yue, Z. F.

    2016-07-01

    In this study, creep experiments on smooth and circumferential V-type notched round bars were conducted in GH3536 Ni-based superalloy at 750 °C to identify notch strengthening effect in notched specimens. FE analysis was carried out, coupled with continuum damage mechanics (CDM), to analyze stress distribution and damage evolution under multiaxial stress state. The creep deformation of smooth specimens and the rupture life of both smooth and notched specimens showed good agreement between experimental results and FE analysis predictions; the creep rupture life for the notched specimen was successfully predicted via the "skeletal point" concept. Both creep damage analysis and the observed fracture morphology suggest that creep rupture started first at the root in the V-type notched specimens, and shifted to the region close to the notch root when the notch was relatively shallow compared to U-type notched specimens.

  16. Physics-Based Modeling of Meteor Entry and Breakup

    Science.gov (United States)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  17. A physically based analytical spatial air temperature and humidity model

    Science.gov (United States)

    Yang Yang; Theodore A. Endreny; David J. Nowak

    2013-01-01

    Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat...

  18. Do burnout and work engagement predict depressive symptoms and life satisfaction? A three-wave seven-year prospective study.

    Science.gov (United States)

    Hakanen, Jari J; Schaufeli, Wilmar B

    2012-12-10

    Burnout and work engagement have been viewed as opposite, yet distinct states of employee well-being. We investigated whether work-related indicators of well-being (i.e. burnout and work engagement) spill-over and generalize to context-free well-being (i.e. depressive symptoms and life satisfaction). More specifically, we examined the causal direction: does burnout/work engagement lead to depressive symptoms/life satisfaction, or the other way around? Three surveys were conducted. In 2003, 71% of all Finnish dentists were surveyed (n=3255), and the response rate of the 3-year follow-up was 84% (n=2555). The second follow-up was conducted four years later with a response rate of 86% (n=1964). Structural equation modeling was used to investigate the cross-lagged associations between the study variables across time. Burnout predicted depressive symptoms and life dissatisfaction from T1 to T2 and from T2 to T3. Conversely, work engagement had a negative effect on depressive symptoms and a positive effect on life satisfaction, both from T1 to T2 and from T2 to T3, even after adjusting for the impact of burnout at every occasion. The study was conducted among one occupational group, which limits its generalizability. Work-related well-being predicts general wellbeing in the long-term. For example, burnout predicts depressive symptoms and not vice versa. In addition, burnout and work engagement are not direct opposites. Instead, both have unique, incremental impacts on life satisfaction and depressive symptoms. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. FKBP5 genotype interacts with early life trauma to predict heavy drinking in college students.

    Science.gov (United States)

    Lieberman, Richard; Armeli, Stephen; Scott, Denise M; Kranzler, Henry R; Tennen, Howard; Covault, Jonathan

    2016-09-01

    Alcohol use disorder (AUD) is debilitating and costly. Identification and better understanding of risk factors influencing the development of AUD remain a research priority. Although early life exposure to trauma increases the risk of adulthood psychiatric disorders, including AUD, many individuals exposed to early life trauma do not develop psychopathology. Underlying genetic factors may contribute to differential sensitivity to trauma experienced in childhood. The hypothalamic-pituitary-adrenal (HPA) axis is susceptible to long-lasting changes in function following childhood trauma. Functional genetic variation within FKBP5, a gene encoding a modulator of HPA axis function, is associated with the development of psychiatric symptoms in adulthood, particularly among individuals exposed to trauma early in life. In the current study, we examined interactions between self-reported early life trauma, past-year life stress, past-year trauma, and a single nucleotide polymorphism (rs1360780) in FKBP5 on heavy alcohol consumption in a sample of 1,845 college students from two university settings. Although we found no effect of early life trauma on heavy drinking in rs1360780*T-allele carriers, rs1360780*C homozygotes exposed to early life trauma had a lower probability of heavy drinking compared to rs1360780*C homozygotes not exposed to early life trauma (P stress or past-year trauma, and FKBP5 genotype on heavy drinking suggests that there exists a developmental period of susceptibility to stress that is moderated by FKBP5 genotype. These findings implicate interactive effects of early life trauma and FKBP5 genetic variation on heavy drinking. © 2016 Wiley Periodicals, Inc.

  20. Non-suicidal self-injury prospectively predicts interpersonal stressful life events and depressive symptoms among adolescent girls.

    Science.gov (United States)

    Burke, Taylor A; Hamilton, Jessica L; Abramson, Lyn Y; Alloy, Lauren B

    2015-08-30

    Non-suicidal self-injury (NSSI) is the deliberate self-harm of one's tissue, engaged in without lethal intent, and occurs frequently among late adolescents. Although research has indicated that NSSI predicts depression, the potential psychosocial mechanisms through which engagement in NSSI makes one susceptible to future depressive symptoms remain unclear. The present study examined whether NSSI increases the risk of experiencing stressful life events, which, in turn, heightens the risk for subsequent depressive symptoms. Drawn from a sample specifically selected for adolescents at high and low risk for developing bipolar spectrum disorders, a total of 110 late-adolescents (mean age=18.74, SD=.69; 73% female) were administered measures of lifetime and past year engagement in NSSI and current depressive symptomatology. Approximately 6 months later, they completed a measure of depressive symptoms and a questionnaire and interview assessing life events that occurred over the 6-month interval. Results suggest that the frequency of lifetime and past year NSSI predicted the occurrence of interpersonal stressful life events beyond the effects of initial depressive symptoms, but only for late adolescent girls. Results further suggest that higher levels of interpersonal stressful life events mediated the relationship between NSSI frequency and prospective increases in depressive symptoms among girls.

  1. Small Crack Growth and Fatigue Life Predictions for High-Strength Aluminium Alloys. Part 1; Experimental and Fracture Mechanics Analysis

    Science.gov (United States)

    Wu, X. R.; Newman, J. C.; Zhao, W.; Swain, M. H.; Ding, C. F.; Phillips, E. P.

    1998-01-01

    The small crack effect was investigated in two high-strength aluminium alloys: 7075-T6 bare and LC9cs clad alloy. Both experimental and analytical investigations were conducted to study crack initiation and growth of small cracks. In the experimental program, fatigue tests, small crack and large crack tests A,ere conducted under constant amplitude and Mini-TWIST spectrum loading conditions. A pronounced small crack effect was observed in both materials, especially for the negative stress ratios. For all loading conditions, most of the fatigue life of the SENT specimens was shown to be crack propagation from initial material defects or from the cladding layer. In the analysis program, three-dimensional finite element and A weight function methods were used to determine stress intensity factors and to develop SIF equations for surface and corner cracks at the notch in the SENT specimens. A plastisity-induced crack-closure model was used to correlate small and large crack data, and to make fatigue life predictions, Predicted crack-growth rates and fatigue lives agreed well with experiments. A total fatigue life prediction method for the aluminum alloys was developed and demonstrated using the crack-closure model.

  2. Scoring life insurance applicants' laboratory results, blood pressure and build to predict all-cause mortality risk.

    Science.gov (United States)

    Fulks, Michael; Stout, Robert L; Dolan, Vera F

    2012-01-01

    Evaluate the degree of medium to longer term mortality prediction possible from a scoring system covering all laboratory testing used for life insurance applicants, as well as blood pressure and build measurements. Using the results of testing for life insurance applicants who reported a Social Security number in conjunction with the Social Security Death Master File, the mortality associated with each test result was defined by age and sex. The individual mortality scores for each test were combined for each individual and a composite mortality risk score was developed. This score was then tested against the insurance applicant dataset to evaluate its ability to discriminate risk across age and sex. The composite risk score was highly predictive of all-cause mortality risk in a linear manner from the best to worst quintile of scores in a nearly identical fashion for each sex and decade of age. Laboratory studies, blood pressure and build from life insurance applicants can be used to create scoring that predicts all-cause mortality across age and sex. Such an approach may hold promise for preventative health screening as well.

  3. Development of a Late-Life Dementia Prediction Index with Supervised Machine Learning in the Population-Based CAIDE Study

    Science.gov (United States)

    Pekkala, Timo; Hall, Anette; Lötjönen, Jyrki; Mattila, Jussi; Soininen, Hilkka; Ngandu, Tiia; Laatikainen, Tiina; Kivipelto, Miia; Solomon, Alina

    2016-01-01

    Background and objective: This study aimed to develop a late-life dementia prediction model using a novel validated supervised machine learning method, the Disease State Index (DSI), in the Finnish population-based CAIDE study. Methods: The CAIDE study was based on previous population-based midlife surveys. CAIDE participants were re-examined twice in late-life, and the first late-life re-examination was used as baseline for the present study. The main study population included 709 cognitively normal subjects at first re-examination who returned to the second re-examination up to 10 years later (incident dementia n = 39). An extended population (n = 1009, incident dementia 151) included non-participants/non-survivors (national registers data). DSI was used to develop a dementia index based on first re-examination assessments. Performance in predicting dementia was assessed as area under the ROC curve (AUC). Results: AUCs for DSI were 0.79 and 0.75 for main and extended populations. Included predictors were cognition, vascular factors, age, subjective memory complaints, and APOE genotype. Conclusion: The supervised machine learning method performed well in identifying comprehensive profiles for predicting dementia development up to 10 years later. DSI could thus be useful for identifying individuals who are most at risk and may benefit from dementia prevention interventions. PMID:27802228

  4. Development of a Late-Life Dementia Prediction Index with Supervised Machine Learning in the Population-Based CAIDE Study.

    Science.gov (United States)

    Pekkala, Timo; Hall, Anette; Lötjönen, Jyrki; Mattila, Jussi; Soininen, Hilkka; Ngandu, Tiia; Laatikainen, Tiina; Kivipelto, Miia; Solomon, Alina

    2017-01-01

    This study aimed to develop a late-life dementia prediction model using a novel validated supervised machine learning method, the Disease State Index (DSI), in the Finnish population-based CAIDE study. The CAIDE study was based on previous population-based midlife surveys. CAIDE participants were re-examined twice in late-life, and the first late-life re-examination was used as baseline for the present study. The main study population included 709 cognitively normal subjects at first re-examination who returned to the second re-examination up to 10 years later (incident dementia n = 39). An extended population (n = 1009, incident dementia 151) included non-participants/non-survivors (national registers data). DSI was used to develop a dementia index based on first re-examination assessments. Performance in predicting dementia was assessed as area under the ROC curve (AUC). AUCs for DSI were 0.79 and 0.75 for main and extended populations. Included predictors were cognition, vascular factors, age, subjective memory complaints, and APOE genotype. The supervised machine learning method performed well in identifying comprehensive profiles for predicting dementia development up to 10 years later. DSI could thus be useful for identifying individuals who are most at risk and may benefit from dementia prevention interventions.

  5. Physics-based hybrid method for multiscale transport in porous media

    Science.gov (United States)

    Yousefzadeh, Mehrdad; Battiato, Ilenia

    2017-09-01

    Despite advancements in the development of multiscale models for flow and reactive transport in porous media, the accurate, efficient and physics-based coupling of multiple scales in hybrid models remains a major theoretical and computational challenge. Improving the predictivity of macroscale predictions by means of multiscale algorithms relative to classical at-scale models is the primary motivation for the development of multiscale simulators. Yet, very few are the quantitative studies that explicitly address the predictive capability of multiscale coupling algorithms as it is still generally not possible to have a priori estimates of the errors that are present when complex flow processes are modeled. We develop a nonintrusive pore-/continuum-scale hybrid model whose coupling error is bounded by the upscaling error, i.e. we build a predictive tightly coupled multiscale scheme. This is accomplished by slightly enlarging the subdomain where continuum-scale equations are locally invalid and analytically defining physics-based coupling conditions at the interfaces separating the two computational sub-domains, while enforcing state variable and flux continuity. The proposed multiscale coupling approach retains the advantages of domain decomposition approaches, including the use of existing solvers for each subdomain, while it gains flexibility in the choice of the numerical discretization method and maintains the coupling errors bounded by the upscaling error. We implement the coupling in finite volumes and test the proposed method by modeling flow and transport through a reactive channel and past an array of heterogeneously reactive cylinders.

  6. Fatigue life prediction of casing welded pipes by using the extended finite element method

    National Research Council Canada - National Science Library

    Ljubica Lazi; Aleksandar Raji; Aleksandar Grbovi; Aleksandar Sedmak; e Sarko

    2016-01-01

      The extended finite element (XFEM) method has been used to simulate fatigue crack growth in casing pipe, made of API J55 steel by high-frequency welding, in order estimate its structural integrity and life...

  7. Satellite Lithium-Ion Battery Remaining Cycle Life Prediction with Novel Indirect Health Indicator Extraction

    OpenAIRE

    Haitao Liao; Wei Xie; Yu Peng; Datong Liu; Hong Wang

    2013-01-01

    Prognostics and remaining useful life (RUL) estimation for lithium-ion batteries play an important role in intelligent battery management systems (BMS). The capacity is often used as the fade indicator for estimating the remaining cycle life of a lithium-ion battery. For spacecraft requiring high reliability and long lifetime, in-orbit RUL estimation and reliability verification on ground should be carefully addressed. However, it is quite challenging to monitor and estimate the capacity of a...

  8. Life history predicts risk of species decline in a stochastic world

    OpenAIRE

    Van Allen, Benjamin G.; Amy E. Dunham; Asquith, Christopher M.; Rudolf, Volker H.W.

    2012-01-01

    Understanding what traits determine the extinction risk of species has been a long-standing challenge. Natural populations increasingly experience reductions in habitat and population size concurrent with increasing novel environmental variation owing to anthropogenic disturbance and climate change. Recent studies show that a species risk of decline towards extinction is often non-random across species with different life histories. We propose that species with life histories in which all sta...

  9. Do clinical assessments, steady-state or daily-life gait characteristics predict falls in ambulatory chronic stroke survivors?

    Science.gov (United States)

    Punt, Michiel; Bruijn, Sjoerd M; Wittink, Harriet; van de Port, Ingrid G; van Dieën, Jaap H

    2017-05-16

    This exploratory study investigated to what extent gait characteristics and clinical physical therapy assessments predict falls in chronic stroke survivors. Prospective study. Chronic fall-prone and non-fall-prone stroke survivors. Steady-state gait characteristics were collected from 40 participants while walking on a treadmill with motion capture of spatio-temporal, variability, and stability measures. An accelerometer was used to collect daily-life gait characteristics during 7 days. Six physical and psychological assessments were administered. Fall events were determined using a "fall calendar" and monthly phone calls over a 6-month period. After data reduction through principal component analysis, the predictive capacity of each method was determined by logistic regression. Thirty-eight percent of the participants were classified as fallers. Laboratory-based and daily-life gait characteristics predicted falls acceptably well, with an area under the curve of, 0.73 and 0.72, respectively, while fall predictions from clinical assessments were limited (0.64). Independent of the type of gait assessment, qualitative gait characteristics are better fall predictors than clinical assessments. Clinicians should therefore consider gait analyses as an alternative for identifying fall-prone stroke survivors.

  10. Integrating 3D geological information with a national physically-based hydrological modelling system

    Science.gov (United States)

    Lewis, Elizabeth; Parkin, Geoff; Kessler, Holger; Whiteman, Mark

    2016-04-01

    Robust numerical models are an essential tool for informing flood and water management and policy around the world. Physically-based hydrological models have traditionally not been used for such applications due to prohibitively large data, time and computational resource requirements. Given recent advances in computing power and data availability, a robust, physically-based hydrological modelling system for Great Britain using the SHETRAN model and national datasets has been created. Such a model has several advantages over less complex systems. Firstly, compared with conceptual models, a national physically-based model is more readily applicable to ungauged catchments, in which hydrological predictions are also required. Secondly, the results of a physically-based system may be more robust under changing conditions such as climate and land cover, as physical processes and relationships are explicitly accounted for. Finally, a fully integrated surface and subsurface model such as SHETRAN offers a wider range of applications compared with simpler schemes, such as assessments of groundwater resources, sediment and nutrient transport and flooding from multiple sources. As such, SHETRAN provides a robust means of simulating numerous terrestrial system processes which will add physical realism when coupled to the JULES land surface model. 306 catchments spanning Great Britain have been modelled using this system. The standard configuration of this system performs satisfactorily (NSE > 0.5) for 72% of catchments and well (NSE > 0.7) for 48%. Many of the remaining 28% of catchments that performed relatively poorly (NSE information into SHETRAN for any model setup. The addition of more realistic subsurface representation following this approach is shown to greatly improve model performance in areas dominated by groundwater processes. The resulting modelling system has great potential to be used as a resource at national, regional and local scales in an array of different

  11. Predictive value of obsessive compulsive symptoms involving the skin on quality of life in patients with acne vulgaris.

    Science.gov (United States)

    Bez, Yasin; Yesilova, Yavuz; Arı, Mustafa; Kaya, Mehmet Cemal; Alpak, Gokay; Bulut, Mahmut

    2013-11-01

    Acne is one of the most common dermatological diseases, and obsessive compulsive disorder is among the most frequent psychiatric conditions seen in dermatology clinics. Comorbidity of these conditions may therefore be expected. The aim of this study was to measure obsessive compulsive symptoms and quality of life in patients with acne vulgaris, compare them with those of healthy control subjects, and determine whether there is any predictive value of obsessive compulsive symptoms for quality of life in patients with acne. Obsessive compulsive symptoms and quality of life measurements of 146 patients with acne vulgaris and 94 healthy control subjects were made using the Maudsley Obsessive Compulsive Questionnaire and Short Form-36 in a cross-sectional design. Patients with acne vulgaris had lower scores for physical functioning, physical role dysfunction, general health perception, vitality, and emotional role dysfunction. They also had higher scores for checking, slowness, and rumination. The only predictor of physical functioning and vitality dimensions of health-related quality of life in these patients was rumination score. Obsessive compulsive symptoms in patients with acne vulgaris are higher than in controls, and this may correlate with both disease severity and quality of life for patients.

  12. STRESS-STRAIN FINITE ELEMENT ANALYSIS AND FATIGUE LIFE PREDICTION FOR BOLTED CONNECTIONS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A cyclic plasticity model is used into finite element (FE) method to obtain the details of elastic-plastic stress-strain in the bolts under cyclic axial loading. Two criteria in multiaxial fatigue are employed to predict fatigue lives of bolts. The predicted fatigue lives are in favorable agreement with the experimental results for machined bolts.

  13. [Prediction method of rural landscape pattern evolution based on life cycle: a case study of Jinjing Town, Hunan Province, China].

    Science.gov (United States)

    Ji, Xiang; Liu, Li-Ming; Li, Hong-Qing

    2014-11-01

    Taking Jinjing Town in Dongting Lake area as a case, this paper analyzed the evolution of rural landscape patterns by means of life cycle theory, simulated the evolution cycle curve, and calculated its evolution period, then combining CA-Markov model, a complete prediction model was built based on the rule of rural landscape change. The results showed that rural settlement and paddy landscapes of Jinjing Town would change most in 2020, with the rural settlement landscape increased to 1194.01 hm2 and paddy landscape greatly reduced to 3090.24 hm2. The quantitative and spatial prediction accuracies of the model were up to 99.3% and 96.4%, respectively, being more explicit than single CA-Markov model. The prediction model of rural landscape patterns change proposed in this paper would be helpful for rural landscape planning in future.

  14. Life beyond MSE and R2 — improving validation of predictive models with observations

    Science.gov (United States)

    Papritz, Andreas; Nussbaum, Madlene

    2017-04-01

    Machine learning and statistical predictive methods are evaluated by the closeness of predictions to observations of a test dataset. Common criteria for rating predictive methods are bias and mean square error (MSE), characterizing systematic and random prediction errors. Many studies also report R2-values, but their meaning is not always clear (correlation between observations and predictions or MSE skill score; Wilks, 2011). The same criteria are also used for choosing tuning parameters of predictive procedures by cross-validation and bagging (e.g. Hastie et al., 2009). For evident reasons, atmospheric sciences have developed a rich box of tools for forecast verification. Specific criteria have been proposed for evaluating deterministic and probabilistic predictions of binary, multinomial, ordinal and continuous responses (see reviews by Wilks, 2011, Jollie and Stephenson, 2012 and Gneiting et al., 2007). It appears that these techniques are not very well-known in the geosciences community interested in machine learning. In our presentation we review techniques that offer more insight into proximity of data and predictions than bias, MSE and R2 alone. We mention here only examples: (i) Graphing observations vs. predictions is usually more appropriate than the reverse (Piñeiro et al., 2008). (ii) The decomposition of the Brier score score (= MSE for probabilistic predictions of binary yes/no data) into reliability and resolution reveals (conditional) bias and capability of discriminating yes/no observations by the predictions. We illustrate the approaches by applications from digital soil mapping studies. Gneiting, T., Balabdaoui, F., and Raftery, A. E. (2007). Probabilistic forecasts, calibration and sharpness. Journal of the Royal Statistical Society Series B, 69, 243-268. Hastie, T., Tibshirani, R., and Friedman, J. (2009). The Elements of Statistical Learning; Data Mining, Inference and Prediction. Springer, New York, second edition. Jolliffe, I. T. and

  15. Physics-based simulation modeling and optimization of microstructural changes induced by machining and selective laser melting processes in titanium and nickel based alloys

    Science.gov (United States)

    Arisoy, Yigit Muzaffer

    Manufacturing processes may significantly affect the quality of resultant surfaces and structural integrity of the metal end products. Controlling manufacturing process induced changes to the product's surface integrity may improve the fatigue life and overall reliability of the end product. The goal of this study is to model the phenomena that result in microstructural alterations and improve the surface integrity of the manufactured parts by utilizing physics-based process simulations and other computational methods. Two different (both conventional and advanced) manufacturing processes; i.e. machining of Titanium and Nickel-based alloys and selective laser melting of Nickel-based powder alloys are studied. 3D Finite Element (FE) process simulations are developed and experimental data that validates these process simulation models are generated to compare against predictions. Computational process modeling and optimization have been performed for machining induced microstructure that includes; i) predicting recrystallization and grain size using FE simulations and the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model, ii) predicting microhardness using non-linear regression models and the Random Forests method, and iii) multi-objective machining optimization for minimizing microstructural changes. Experimental analysis and computational process modeling of selective laser melting have been also conducted including; i) microstructural analysis of grain sizes and growth directions using SEM imaging and machine learning algorithms, ii) analysis of thermal imaging for spattering, heating/cooling rates and meltpool size, iii) predicting thermal field, meltpool size, and growth directions via thermal gradients using 3D FE simulations, iv) predicting localized solidification using the Phase Field method. These computational process models and predictive models, once utilized by industry to optimize process parameters, have the ultimate potential to improve performance of

  16. Self-concept clarity and religious orientations: prediction of purpose in life and self-esteem.

    Science.gov (United States)

    Błażek, Magdalena; Besta, Tomasz

    2012-09-01

    The present study concerns the relationship between self-concept clarity, religiosity, and well-being, as well as the mediating influence of religiosity on the relationship between self-concept clarity and sense of meaning in life and self-esteem. Self-concept clarity was found to be a significant predictor of sense of meaning in life and self-esteem; intrinsic religious orientation was found to be a predictor of sense of meaning in life, while the quest religious orientation was a predictor for self-esteem. The cross-products of self-concept clarity and intrinsic religious orientation were found to be related to the sense of purpose in life, which would point to religiosity being a mediator of the relationship between self-concept clarity and sense of purpose in life. The cross-products of self-concept clarity and quest religious orientation were found to be a predictor of self-esteem, which indicates a mediating effect of this religious orientation in the relationship of self-concept clarity and self-esteem.

  17. Predicting quality of life for people living with HIV: international evidence from seven cultures.

    Science.gov (United States)

    Skevington, S M; Norweg, S; Standage, M

    2010-05-01

    The need for a validated quality of life (QOL) model focussing on people living with HIV/AIDS has led to an international re-evaluation and extension of the Chronic Illness Quality of Life model using complex latent modelling techniques. After reoperationalising six model variables and including independence and sex-life, the WHOQOL-HIV was administered to 1281 people with asymptomatic-HIV (42%), symptomatic-HIV (40%) or AIDS (18%; 34 years; 62% male) living in Australia, Brazil, India (north & south), Italy, Thailand and Ukraine. The overall model fit was acceptable. Social inclusion did not directly improve QOL, but increased positive feelings, social support and perceived improvements of access to health and social care; all three improved QOL. Social inclusion increased perceived physical health indirectly through positive feelings. Better physical health improved sex-life and gave greater independence; both improved QOL. Gender and disease stage models were acceptable, fitting best for men and asymptomatic-HIV. Similar aspects of QOL were depleted for women and some disease stages. Increased social support did not consistently improve independence or positive feelings. Positive feelings improved the sex-life of men and those with asymptomatic-HIV. This cross-cultural approach combining assessment with theory, could guide future international interventions and practice.

  18. Streambed microstructure predicts evolution of development and life history mode in the plethodontid salamander Eurycea tynerensis.

    Science.gov (United States)

    Bonett, Ronald M; Chippindale, Paul T

    2006-03-02

    Habitat variation strongly influences the evolution of developmentally flexible traits, and may drive speciation and diversification. The plethodontid salamander Eurycea tynerensis is endemic to the geologically diverse Ozark Plateau of south-central North America, and comprises both strictly aquatic paedomorphic populations (achieving reproductive maturity while remaining in the larval form) and more terrestrial metamorphic populations. The switch between developmental modes has occurred many times, but populations typically exhibit a single life history mode. This unique system offers an opportunity to study the specific ecological circumstances under which alternate developmental and life history modes evolve. We use phylogenetic independent contrasts to test for relationships between a key microhabitat feature (streambed sediment) and this major life history polymorphism. We find streambed microstructure (sediment particle size, type and degree of sorting) to be highly correlated with life-history mode. Eurycea tynerensis is paedomorphic in streams containing large chert gravel, but metamorphoses in nearby streams containing poorly sorted, clastic material such as sandstone or siltstone. Deposits of large chert gravel create loosely associated streambeds, which provide access to subsurface water during dry summer months. Conversely, streambeds composed of more densely packed sandstone and siltstone sediments leave no subterranean refuge when surface water dries, presumably necessitating metamorphosis and use of terrestrial habitats. This represents a clear example of the relationship between microhabitat structure and evolution of a major developmental and life history trait, and has broad implications for the role of localized ecological conditions on larger-scale evolutionary processes.

  19. Do stressful life events predict medical treatment outcome in first episode of depression?

    DEFF Research Database (Denmark)

    Bock, Camilla; Bukh, Jens Drachmann; Vinberg, Maj

    2009-01-01

    BACKGROUND: It is unclear whether medical treatment outcome in first episode depression differ for patients with and without stressful life events prior to onset of depression. METHODS: Patients discharged with a diagnosis of a single depressive episode from a psychiatric in- or outpatient hospital......-II) and the interview of recent life events (IRLE). Medical treatment history was assessed in detail using standardised procedures (TRAQ). Remission was defined as a score Depression Rating Scale, 17 items and a score >or= 4 on TRAQ following (1) first trial of antidepressant treatment (2) two...... adequate trials of antidepressant treatment. RESULTS: A total of 399 patients participated in the interview and among these 301 patients obtained a SCAN diagnosis of a single depressive episode. A total of 62.8% of the 301 patients experienced at least one moderate to severe stressful life event in a 6...

  20. The Value of a Purposeful Life: Sense of Purpose Predicts Greater Income and Net Worth.

    Science.gov (United States)

    Hill, Patrick L; Turiano, Nicholas A; Mroczek, Daniel K; Burrow, Anthony L

    2016-12-01

    Having a sense of purpose in life appears valuable across life domains, though it remains unclear whether purpose also provides financial value to individuals. The current study examined sense of purpose as a predictor of concurrent and longitudinal income and net worth levels, using two waves of the MIDUS sample of adults (N = 4660 across both assessments). Participants who reported a higher sense of purpose had higher levels of household income and net worth initially, and were more likely to increase on these financial outcomes over the nine years between assessments. Interaction tests suggested some evidence of age moderation, but gender did not appear to moderate the influence of purpose on economic outcomes.

  1. Using Data Reduction Methods To Predict Quality Of Life In Brest ...

    African Journals Online (AJOL)

    But usually existed a lot of factor cause difficulty for fitting the models and predicting. ... method of data reduction was used for reducing the number of predictors. ... regression showed that only role function, social function and diarrhea were ...

  2. An Adaptive Recurrent Neural Network for Remaining Useful Life Prediction of Lithium-ion Batteries

    Data.gov (United States)

    National Aeronautics and Space Administration — Prognostics is an emerging science of predicting the health condition of a system (or its components) based upon current and previous system states. A reliable...

  3. Physics-based signal processing algorithms for micromachined cantilever arrays

    Science.gov (United States)

    Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

    2013-11-19

    A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.

  4. Shelf-life prediction models for ready-to-eat fresh cut salads: Testing in real cold chain.

    Science.gov (United States)

    Tsironi, Theofania; Dermesonlouoglou, Efimia; Giannoglou, Marianna; Gogou, Eleni; Katsaros, George; Taoukis, Petros

    2017-01-02

    The aim of the study was to develop and test the applicability of predictive models for shelf-life estimation of ready-to-eat (RTE) fresh cut salads in realistic distribution temperature conditions in the food supply chain. A systematic kinetic study of quality loss of RTE mixed salad (lollo rosso lettuce-40%, lollo verde lettuce-45%, rocket-15%) packed under modified atmospheres (3% O2, 10% CO2, 87% N2) was conducted. Microbial population (total viable count, Pseudomonas spp., lactic acid bacteria), vitamin C, colour and texture were the measured quality parameters. Kinetic models for these indices were developed to determine the quality loss and calculate product remaining shelf-life (SLR). Storage experiments were conducted at isothermal (2.5-15°C) and non-isothermal temperature conditions (Teff=7.8°C defined as the constant temperature that results in the same quality value as the variable temperature distribution) for validation purposes. Pseudomonas dominated spoilage, followed by browning and chemical changes. The end of shelf-life correlated with a Pseudomonas spp. level of 8 log(cfu/g), and 20% loss of the initial vitamin C content. The effect of temperature on these quality parameters was expressed by the Arrhenius equation; activation energy (Ea) value was 69.1 and 122.6kJ/mol for Pseudomonas spp. growth and vitamin C loss rates, respectively. Shelf-life prediction models were also validated in real cold chain conditions (including the stages of transport to and storage at retail distribution center, transport to and display at 7 retail stores, transport to and storage in domestic refrigerators). The quality level and SLR estimated after 2-3days of domestic storage (time of consumption) ranged between 1 and 8days at 4°C and was predicted within satisfactory statistical error by the kinetic models. Teff in the cold chain ranged between 3.7 and 8.3°C. Using the validated models, SLR of RTE fresh cut salad can be estimated at any point of the cold chain

  5. Informed decision making about predictive DNA tests: arguments for more public visibility of personal deliberations about the good life.

    Science.gov (United States)

    Boenink, Marianne; van der Burg, Simone

    2010-05-01

    Since its advent, predictive DNA testing has been perceived as a technology that may have considerable impact on the quality of people's life. The decision whether or not to use this technology is up to the individual client. However, to enable well considered decision making both the negative as well as the positive freedom of the individual should be supported. In this paper, we argue that current professional and public discourse on predictive DNA-testing is lacking when it comes to supporting positive freedom, because it is usually framed in terms of risk and risk management. We show how this 'risk discourse' steers thinking on the good life in a particular way. We go on to argue that empirical research into the actual deliberation and decision making processes of individuals and families may be used to enrich the environment of personal deliberation in three ways: (1) it points at a richer set of values that deliberators can take into account, (2) it acknowledges the shared nature of genes, and (3) it shows how one might frame decisions in a non-binary way. We argue that the public sharing and discussing of stories about personal deliberations offers valuable input for others who face similar choices: it fosters their positive freedom to shape their view of the good life in relation to DNA-diagnostics. We conclude by offering some suggestions as to how to realize such public sharing of personal stories.

  6. Predicting health-related quality of life of parents of children with inherited metabolic diseases

    NARCIS (Netherlands)

    Hatzmann, J.; Valstar, M.J.; Bosch, A.; Wijburg, F.A.; Heymans, H.S.; Grootenhuis, M.A.

    2009-01-01

    1 year before the start of the study, living at home). Parents were approached through the Emma Children's Hospital, and through a national parent and patient association. HRQoL was assessed using the TNO-AZL Questionnaire for Adult's Health Related Quality of Life (TAAQOL), describing 12 domains of

  7. Precocity Predicts Shorter Life for Major League Baseball Players: Confirmation of Mccann's Precocity-Longevity Hypothesis

    Science.gov (United States)

    Abel, Ernest L.; Kruger, Michael L.

    2007-01-01

    We tested McCann's precocity-longevity hypothesis, which proposes that early career achievement is related to premature death, for Major League baseball players (N = 3,760). Age at debut was the definition for precocity. We controlled for possible artifacts of life expectancy selection, the "healthy worker" effect, player position, and body-mass…

  8. Profiles of Observed Infant Anger Predict Preschool Behavior Problems: Moderation by Life Stress

    Science.gov (United States)

    Brooker, Rebecca J.; Buss, Kristin A.; Lemery-Chalfant, Kathryn; Aksan, Nazan; Davidson, Richard J.; Goldsmith, H. Hill

    2014-01-01

    Using both traditional composites and novel profiles of anger, we examined associations between infant anger and preschool behavior problems in a large, longitudinal data set (N = 966). We also tested the role of life stress as a moderator of the link between early anger and the development of behavior problems. Although traditional measures of…

  9. Predicting health-related quality of life of parents of children with inherited metabolic diseases

    NARCIS (Netherlands)

    Hatzmann, J.; Valstar, M.J.; Bosch, A.; Wijburg, F.A.; Heymans, H.S.; Grootenhuis, M.A.

    2009-01-01

    1 year before the start of the study, living at home). Parents were approached through the Emma Children's Hospital, and through a national parent and patient association. HRQoL was assessed using the TNO-AZL Questionnaire for Adult's Health Related Quality of Life (TAAQOL), describing 12 domains of

  10. Predicting the Job and Life Satisfaction of Italian Teachers: Test of a Social Cognitive Model

    Science.gov (United States)

    Lent, Robert W.; Nota, Laura; Soresi, Salvatore; Ginevra, Maria C.; Duffy, Ryan D.; Brown, Steven D.

    2011-01-01

    This study tested a social cognitive model of work and life satisfaction (Lent & Brown, 2006, 2008) in a sample of 235 Italian school teachers. The model offered good overall fit to the data, though not all individual path coefficients were significant. Three of five predictors (favorable work conditions, efficacy-relevant supports, and…

  11. Prediction of mortality in type 2 diabetes from health-related quality of life (ZODIAC-4)

    NARCIS (Netherlands)

    Kleefstra, N.; Houweling, S.T.; Ubink-Veltmaat, L.J.; Logtenberg, S.J.J.; Meyboom-de Jong, B.; Coyne, J.C.; Groenier, K.H.; Bilo, H.J.G.; Landman, G.

    2008-01-01

    OBJECTIVE - To investigate the relationship between health-related quality of life (HRQOL) and mortality in type 2 diabetes. RESEARCH DESIGN AND METHODS - In 1998,1,143 primary care patients with type 2 diabetes participated in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIA

  12. Comparing quality of life dimension in different age decades: prediction for aging

    Directory of Open Access Journals (Sweden)

    Vahid Nejati

    2012-02-01

    Full Text Available Background & Objective: Quality of life in different age groups can consider as good predictor of elderly quality of life. The purpose of present study is comparing quality of life in different age decade. Materials & Methods: This cross sectional study performed in 1914 citizens of Tehran with SF36 questionnaire. Sample selection method was multistage classification. We used One Way ANOVA for analysis. Results: Findings show that quality of life dimension reduced in role physical, physical activity, general health, mental health and bodily pain. (P- Value was less than 0.05 for role physical and less than 0.01 for all others. Falling in bodily pain started in 30 years old and for general health 40, physical activity and mental health 60 and role physical role 70 years old. Conclusion: Based on our finding education and intervention for bodily pain should be started at age 30 years old and for general health in 40 years old. Age matched physical activity should be educated for people above 60 years old.

  13. Nomogram for Predicting Time to Death After Withdrawal of Life-Sustaining Treatment in Patients With Devastating Neurological Injury.

    Science.gov (United States)

    He, X; Xu, G; Liang, W; Liu, B; Xu, Y; Luan, Z; Lu, Y; Ko, D S C; Manyalich, M; Schroder, P M; Guo, Z

    2015-08-01

    Reliable prediction of time of death after withdrawal of life-sustaining treatment in patients with devastating neurological injury is crucial to successful donation after cardiac death. Herein, we conducted a study of 419 neurocritical patients who underwent life support withdrawal at four neurosurgical centers in China. Based on a retrospective cohort, we used multivariate Cox regression analysis to identify prognostic factors for patient death, which were then integrated into a nomogram. The model was calibrated and validated using data from an external retrospective cohort and a prospective cohort. We identified 10 variables that were incorporated into a nomogram. The C-indexes for predicting the 60-min death probability in the training, external validation and prospective validation cohorts were 0.96 (0.93-0.98), 0.94 (0.91-0.97), and 0.99 (0.97-1.00), respectively. The calibration plots after WLST showed an optimal agreement between the prediction of time to death by the nomogram and the actual observation for all cohorts. Then we identified 22, 26 and 37 as cut-points for risk stratification into four groups. Kaplan-Meier curves indicated distinct prognoses between patients in the different risk groups (p death donors in neurocritical patients in a Chinese population.

  14. An equivalent strain/Coffin-Manson approach to multiaxial fatigue and life prediction in superelastic Nitinol medical devices.

    Science.gov (United States)

    Runciman, Amanda; Xu, David; Pelton, Alan R; Ritchie, Robert O

    2011-08-01

    Medical devices, particularly endovascular stents, manufactured from superelastic Nitinol, a near-equiatomic alloy of Ni and Ti, are subjected to complex mixed-mode loading conditions in vivo, including axial tension and compression, radial compression, pulsatile, bending and torsion. Fatigue lifetime prediction methodologies for Nitinol, however, are invariably based on uniaxial loading and thus fall short of accurately predicting the safe lifetime of stents under the complex multiaxial loading conditions experienced physiologically. While there is a considerable body of research documented on the cyclic fatigue of Nitinol in uniaxial tension or bending, there remains an almost total lack of comprehensive fatigue lifetime data for other loading conditions, such as torsion and tension/torsion. In this work, thin-walled Nitinol tubes were cycled in torsion at various mean and alternating strains to investigate the fatigue life behavior of Nitinol and results compared to equivalent fatigue data collected under uniaxial tensile/bending loads. Using these strain-life results for various loading modes and an equivalent referential (Lagrangian) strain approach, a strategy for normalizing these data is presented. Based on this strategy, a fatigue lifetime prediction model for the multiaxial loading of Nitinol is presented utilizing a modified Coffin-Manson approach where the number of cycles to failure is related to the equivalent alternating transformation strain.

  15. Individual Differences in Loss Aversion: Conscientiousness Predicts How Life Satisfaction Responds to Losses Versus Gains in Income.

    Science.gov (United States)

    Boyce, Christopher J; Wood, Alex M; Ferguson, Eamonn

    2016-04-01

    Loss aversion is considered a general pervasive bias occurring regardless of the context or the person making the decision. We hypothesized that conscientiousness would predict an aversion to losses in the financial domain. We index loss aversion by the relative impact of income losses and gains on life satisfaction. In a representative German sample (N = 105,558; replicated in a British sample, N = 33,848), with conscientiousness measured at baseline, those high on conscientiousness have the strongest reactions to income losses, suggesting a pronounced loss aversion effect, whereas for those moderately unconscientious, there is no loss aversion effect. Our research (a) provides the first evidence of personality moderation of any loss aversion phenomena, (b) supports contextual perspectives that both personality and situational factors need to be examined in combination, (c) shows that the small but robust relationship between income and life satisfaction is driven primarily by a subset of people experiencing highly impactful losses.

  16. Fatigue life prediction and experiment research for composite laminates with circular hole

    Institute of Scientific and Technical Information of China (English)

    齐红宇; 温卫东; 孙联文

    2004-01-01

    Based on the fatigue prediction model of exponential function and Whitney-Nuismer(WN) criterion of static strength for the composite material laminate with a circular hole, the stress correct factor (β) was put forward and a new fatigue prediction model for composite material laminate was set up. T300/KH304, which is recently studied and is a high capability composite material, was used as the raw material. In order to gain the factorβ, the fatigue experiments of the laminates with holes in different diameters and the same ratio of width to diameter were conducted. The fatigue analysis and tests of the laminates with a hole 5 mm in diameter are carried out at different stress levels, and the results meet the engineering requirement. The simple, prompt and practical method is provided for the prediction of S-N curve of composite laminate with a circular hole.

  17. Predicting married and cohabiting couples' futures from their descriptions of stepfamily life.

    Science.gov (United States)

    Slattery, Maddy E; Bruce, Vanessa; Halford, W Kim; Nicholson, Jan M

    2011-08-01

    Stepfamily couples experience specific challenges early in their relationships, (e.g., reaching agreement on the role of the stepparent in parenting). The Oral History Interview for Stepfamilies (OHI-S) was developed to assess spouses' cognitive representations of their adaptation to these challenges. It was hypothesized that their responses would predict future relationship satisfaction and stability. One-hundred and 22 stepfamily couples completed the OHI-S and were assessed on relationship satisfaction and stability at Time 1 and 2.5 years later (Time 2). Time 2 relationship satisfaction and stability were both predicted by the OHI-S at Time 1. Couples' perceptions of the stepfamily and couple relationship predict separation, and suggest there is an opportunity for early intervention to enhance stepfamily couple relationships.

  18. Prediction of Fatigue Life of a Continuous Bridge Girder Based on Vehicle Induced Stress History

    Directory of Open Access Journals (Sweden)

    V.G. Rao

    2003-01-01

    Full Text Available The fatigue damage assessment of bridge components by conducting a full scale fatigue testing is often prohibitive. A need, therefore, exists to estimate the fatigue damage in bridge components by a simulation of bridge-vehicle interaction dynamics due to the action of the actual traffic. In the present paper, a systematic method has been outlined to find the fatigue damage in the continuous bridge girder based on stress range frequency histogram and fatigue strength parameters of the bridge materials. Vehicle induced time history of maximum flexural stresses has been obtained by Monte Carlo simulation process and utilized to develop the stress range frequency histogram taking into consideration of the annual traffic volume. The linear damage accumulation theory is then applied to calculate cumulative damage index and fatigue life of the bridge. Effect of the bridge span, pavement condition, increase of vehicle operating speed, weight and suspension characteristics on fatigue life of the bridge have been examined.

  19. Noncontact monitoring of surface-wave nonlinearity for predicting the remaining life of fatigued steels

    Science.gov (United States)

    Ogi, Hirotsugu; Hirao, Masahiko; Aoki, Shinji

    2001-07-01

    A nonlinear acoustic measurement is studied for fatigue damage monitoring. An electromagnetic acoustic transducer (EMAT) magnetostrictively couples to a surface-shear-wave resonance along the circumference of a rod specimen during rotating bending fatigue of carbon steels. Excitation of the EMAT at half of the resonance frequency caused the standing wave to contain only the second-harmonic component, which was received by the same EMAT to determine the second-harmonic amplitude. Thus measured surface-wave nonlinearity always showed two distinct peaks at 60% and 85% of the total life. We attribute the earlier peak to crack nucleation and growth, and the later peak to an increase of free dislocations associated with crack extension in the final stage. This noncontact resonance-EMAT measurement can monitor the evolution of the surface-shear-wave nonlinearity throughout the metal's fatigue life and detect the pertinent precursors of the eventual failure.

  20. Fatigue life prediction of casing welded pipes by using the extended finite element method

    Directory of Open Access Journals (Sweden)

    Ljubica Lazić Vulićević

    2016-03-01

    Full Text Available The extended finite element (XFEM method has been used to simulate fatigue crack growth in casing pipe, made of API J55 steel by high-frequency welding, in order estimate its structural integrity and life. Based on the critical value of stress intensity factor KIc, measured in different regions of welded joint, the crack was located in the base metal as the region with the lowest resistance to crack initiation and propagation. The XFEM was first applied to the 3 point bending specimens to verify numerical results with the experimental ones. After successful verification, the XFEM was used to simulate fatigue crack growth, position axially in the pipe, and estimate its remaining life.

  1. Fatigue Analysis and Life Prediction of Dumpers with Cumulative Fatigue Damage Approach

    Institute of Scientific and Technical Information of China (English)

    LI Shouju; LIU Yingxi; SUN Huiling

    2004-01-01

    A fatigue damage model is developed for evaluating accumulative fatigue damage of dumpers. The loading spectrums acted on dumpers are created according to measured strain data in field. The finite element analysis is carried out for assessing stress distribution and strength characteristics of dumpers. Fatigue damage indexes and service life are calculated by a modified Palmgren-Miner rule. The investigation shows that fatigue notch factor has a significant influence on the calculation of fatigue damage of dumpers.

  2. Symptoms of borderline personality disorder predict interpersonal (but not independent) stressful life events in a community sample of older adults.

    Science.gov (United States)

    Powers, Abigail D; Gleason, Marci E J; Oltmanns, Thomas F

    2013-05-01

    Individuals with borderline personality disorder (BPD) often experience stressful life events at a higher frequency than those without BPD. It is less clear what specific types of events are involved in this effect, and it has not been determined whether some features of BPD are more important than others in accounting for this effect. The latter issue is important in light of the heterogeneous nature of this diagnostic construct. These issues were examined in a large, representative community sample of men and women, ages 55-64. Ten Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev., DSM-IV-TR, Washington, DC, American Psychiatric Association, 2000) personality disorders were assessed at baseline using the Structured Interview for DSM-IV Personality: SIDP-IV (B. Pfohl, N. Blum, & M. Zimmerman, 1997, Washington, DC, American Psychiatric Press). Life events were measured at three sequential assessments following baseline at 6-month (N = 1,294), 12-month (N = 1,070), and 18-month (N = 837) follow-ups. Stressful life events were identified using a self-report questionnaire (LTE-Q; List of Threatening Experiences Questionnaire: A subset of prescribed life events with considerable long-term contextual threat by T. Brugha, C. Bebbington, P. Tennant, and J. Hurry, 1985, Psychological Medicine, Vol. 15, pp. 189-194.) followed by a telephone interview. Only borderline personality pathology was related to an increase in the frequency of interpersonal stressful life events. Three specific symptoms of BPD were largely responsible for this connection: unstable interpersonal relationships, impulsivity, and chronic feelings of emptiness (negative association). Symptoms of avoidant and schizoid personality disorders were associated with a reduced number of stressful life events that are considered to be outside a person's control (e.g., serious illness, injury, or death of a loved one). None of the personality disorders predicted an increase in the number of

  3. Boredom proneness predicts quality of life in outpatients diagnosed with schizophrenia-spectrum disorders.

    Science.gov (United States)

    Gerritsen, Cory J; Goldberg, Joel O; Eastwood, John D

    2015-12-01

    There is increasing recognition of the clinical significance of boredom associated with functional impairments in schizophrenia. Previous work has highlighted the importance of motivational deficits more broadly, although no study has yet explored the unique effects of boredom on community outcomes. This study aims to measure boredom proneness among outpatients diagnosed with schizophrenia to determine whether it is elevated in this population and to determine its relation to quality-of-life outcomes. A self-report measure of boredom proneness along with standard measures of symptoms and functional status was administered to a community-dwelling sample of schizophrenia outpatients. Boredom proneness was found to be elevated in this population and was associated with reduced quality of life, specifically with leisure activity dissatisfaction and reduced sense of financial well-being. Negative symptoms were determined to be associated with reduced work and school functioning. This pattern of unique effects on quality of life highlights the clinical relevance of identifying a subjective state of boredom and has theoretical importance in distinguishing boredom proneness specifically from more general avolitional and amotivational conditions that have tended to be the focus of clinical observation and previous research. © The Author(s) 2015.

  4. Self-care and Professional Quality of Life: Predictive Factors among MSW Practitioners

    Directory of Open Access Journals (Sweden)

    Kori R Bloomquist

    2016-02-01

    Full Text Available This study explored the effects of self-care practices and perceptions on positive and negative indicators of professional quality of life, including burnout, secondary traumatic stress, and compassion satisfaction among MSW practitioners. Results reveal that while social workers value and believe self-care is effective in alleviating job-related stress, they engage in self-care on a limited basis. Findings indicate that MSW programs and employers do not teach social workers how to effectively engage in self-care practice. Various domains of self-care practice contribute differently to indicators of professional quality of life. This study sheds light on the under-studied relationship between social worker self-care and professional quality of life, provides insights into the types of activities practiced and not practiced by MSW practitioners, and identifies gaps between perceived value and effective teaching of self-care. Implications exist for social work educators and employers and the potential to support a healthier, sustainable workforce.

  5. Prediction of adolescent and adult adiposity outcomes from early life anthropometrics

    DEFF Research Database (Denmark)

    Graversen, Lise; Sørensen, Thorkild I A; Gerds, Thomas A;

    2014-01-01

    to the NFBC1986, and aimed at labelling 10% as "at risk" on the basis of anthropometric information collected until 5 years of age showed that half of those at risk in fact did become overweight. This group constituted one-third of all who became overweight. CONCLUSIONS: Our prediction model identified...

  6. Physics-based scoring of protein-ligand interactions: explicit polarizability, quantum mechanics and free energies.

    Science.gov (United States)

    Bryce, Richard A

    2011-04-01

    The ability to accurately predict the interaction of a ligand with its receptor is a key limitation in computer-aided drug design approaches such as virtual screening and de novo design. In this article, we examine current strategies for a physics-based approach to scoring of protein-ligand affinity, as well as outlining recent developments in force fields and quantum chemical techniques. We also consider advances in the development and application of simulation-based free energy methods to study protein-ligand interactions. Fuelled by recent advances in computational algorithms and hardware, there is the opportunity for increased integration of physics-based scoring approaches at earlier stages in computationally guided drug discovery. Specifically, we envisage increased use of implicit solvent models and simulation-based scoring methods as tools for computing the affinities of large virtual ligand libraries. Approaches based on end point simulations and reference potentials allow the application of more advanced potential energy functions to prediction of protein-ligand binding affinities. Comprehensive evaluation of polarizable force fields and quantum mechanical (QM)/molecular mechanical and QM methods in scoring of protein-ligand interactions is required, particularly in their ability to address challenging targets such as metalloproteins and other proteins that make highly polar interactions. Finally, we anticipate increasingly quantitative free energy perturbation and thermodynamic integration methods that are practical for optimization of hits obtained from screened ligand libraries.

  7. Remaining Useful Life Prediction of Lithium-Ion Batteries Based on the Wiener Process with Measurement Error

    Directory of Open Access Journals (Sweden)

    Shengjin Tang

    2014-01-01

    Full Text Available Remaining useful life (RUL prediction is central to the prognostics and health management (PHM of lithium-ion batteries. This paper proposes a novel RUL prediction method for lithium-ion batteries based on the Wiener process with measurement error (WPME. First, we use the truncated normal distribution (TND based modeling approach for the estimated degradation state and obtain an exact and closed-form RUL distribution by simultaneously considering the measurement uncertainty and the distribution of the estimated drift parameter. Then, the traditional maximum likelihood estimation (MLE method for population based parameters estimation is remedied to improve the estimation efficiency. Additionally, we analyze the relationship between the classic MLE method and the combination of the Bayesian updating algorithm and the expectation maximization algorithm for the real time RUL prediction. Interestingly, it is found that the result of the combination algorithm is equal to the classic MLE method. Inspired by this observation, a heuristic algorithm for the real time parameters updating is presented. Finally, numerical examples and a case study of lithium-ion batteries are provided to substantiate the superiority of the proposed RUL prediction method.

  8. Service life prediction. Development of models for predicting the service life of power plant components subject to thermomechanical creep fatigue; Lebensdauervorhersage. Entwicklung von Modellen zur Lebensdauervorhersage von Kraftwerksbauteilen unter thermisch-mechanischer Kriechermuedungsbeanspruchung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Cui, L.; Scholz, A. [Technische Univ. Darmstadt (Germany). Institut fuer Werkstoffkunde; Hartrott, P. von; Schlesinger, M. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    2009-07-01

    Extensive use is made of massive components of heat resistant and highly heat resistant materials in installations of the power and heating industry. These components are exposed to varying thermomechanical stress as a result of ramping-up and down processes. In this research project two computer-assisted methods of predicting service life until crack initiation were extended to include cases of thermomechanical multi-axis stress conducive to creep fatigue and of superposition of high-cycle stress on power plant components. Investigations were limited to rotor steel of type X12CrMoWVNbN10-1-1. Complex thermomechanical multi-axis experiments were performed on round, notched and cruciform test specimens of close-to-life dimensions in order to demonstrate by experiment the validity of these models. The results of these calculations showed an acceptable degree of agreement between experiment and simulation for both models. Calculations on earlier TMF experiments performed at IfW on hollow specimens of 1%CrMoNiV showed good predictability for both the SARA and the ThoMat programme. Calculations on experiments performed at MPA Stuttgart on model bodies consisting of the same 1%CrMoNiV showed a predictability of acceptable variability considering the complexity of the stresses involved. A further outcome of this project is that the use of SARA appears universally suitable for the construction of new plants and in the service area, while the use of ThoMat appears suited for detail optimisation in the development process.

  9. Fatigue life prediction of casing welded pipes by using the extended finite element method

    OpenAIRE

    2016-01-01

    The extended finite element (XFEM) method has been used to simulate fatigue crack growth in casing pipe, made of API J55 steel by high-frequency welding, in order estimate its structural integrity and life. Based on the critical value of stress intensity factor KIc, measured in different regions of welded joint, the crack was located in the base metal as the region with the lowest resistance to crack initiation and propagation. The XFEM was first applied to the 3 point bending specimens to...

  10. On the life time prediction of repeatedly impacted thermoplastic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Mustafa Ozguer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey)], E-mail: ozgur_bora@yahoo.com; Coban, Onur [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Sinmazcelik, Tamer [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); TUBITAK-MAM, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey); Cuerguel, Ismail [Kocaeli University, Mechanical Engineering Department, Veziroglu Campus, 41040 Izmit (Turkey); Guenay, Volkan [TUBITAK-MAM, Materials Institute, P.O. Box 21, 41470 Gebze (Turkey)

    2009-01-15

    Impact-fatigue properties of unidirectional carbon fibre reinforced polyetherimide (PEI) composites were investigated. Low velocity repeated impacts were performed by using pendulum type instrumented impact tester (Ceast, Resil 25) at energy levels ranging 0.54-0.94 J. Samples were prepared according to ISO 180 and subjected to repeated low velocity impacts up to fracture by the hammer. Results of repeated impact study are reported in terms of peak load (F{sub max}), absorbed energy (E{sub max}) and number of repeated impacts. An analytical model to describe the life time of composite materials subjected to repeated impact loadings was presented.

  11. On the development of life prediction methodologies for the failure of human teeth

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, R.K.; Imbeni, V.; Kinney, J.H.; Marshall, S.J.; Ritchie, R.O.

    2002-09-18

    Human dentin is known to be susceptible to failure under cyclic loading. Surprisingly, there are few reports that quantify the effect of such loading, considering the fact that a typical tooth experiences a million or so loading cycles annually. In the present study, a systematic investigation is described of the effects of prolonged cyclic loading on human dentin in a simulated physiological environment. In vitro stress-life (S/N) data are discussed in the context of possible mechanisms of fatigue damage and failure.

  12. Life Satisfaction among Highly Achieving Students in Hong Kong: Do Gratitude and the "Good-Enough Mindset" Add to the Contribution of Perfectionism in Prediction?

    Science.gov (United States)

    Chan, David W.

    2012-01-01

    This study investigated whether gratitude and the "good-enough mindset" added to the contribution of perfectionism in predicting life satisfaction in 245 Chinese highly achieving students in Hong Kong. Participants completed self-report questionnaires that included scales on life satisfaction, positive and negative perfectionism…

  13. Life Satisfaction among Highly Achieving Students in Hong Kong: Do Gratitude and the "Good-Enough Mindset" Add to the Contribution of Perfectionism in Prediction?

    Science.gov (United States)

    Chan, David W.

    2012-01-01

    This study investigated whether gratitude and the "good-enough mindset" added to the contribution of perfectionism in predicting life satisfaction in 245 Chinese highly achieving students in Hong Kong. Participants completed self-report questionnaires that included scales on life satisfaction, positive and negative perfectionism…

  14. Becoming popular: interpersonal emotion regulation predicts relationship formation in real life social networks

    OpenAIRE

    Karen eNiven; David eGarcia; Ilmo evan der Löwe; David eHolman; Warren eMansell

    2015-01-01

    Building relationships is crucial for satisfaction and success, especially when entering new social contexts. In the present paper, we investigate whether attempting to improve others’ feelings helps people to make connections in new networks. In Study 1, a social network study following new networks of people for a twelve-week period indicated that use of interpersonal emotion regulation (IER) strategies predicted growth in popularity, as indicated by other network members’ reports of spendi...

  15. Teaching Physical Based Animation via OpenGL Slides

    Science.gov (United States)

    Song, Miao; Mokhov, Serguei A.; Grogono, Peter

    This work expands further our earlier poster presentation and integration of the OpenGL Slides Framework (OGLSF) - to make presentations with real-time animated graphics where each slide is a scene with tidgets - and physical based animation of elastic two-, three-layer softbody objects. The whole project is very interactive, and serves dual purpose - delivering the teaching material in a classroom setting with real running animated examples as well as releasing the source code to the students to show how the actual working things are made.

  16. A Physically Based Transmission Model of Rough Surfaces

    Directory of Open Access Journals (Sweden)

    Yinlong Sun

    2008-11-01

    Full Text Available Transparent and translucent objects involve both light reflection and transmission at surfaces. This paper presents a physically based transmission model of rough surface. The surface is assumed to be locally smooth, and statistical techniques is applied to calculate light transmission through a local illumination area. We have obtained an analytical expression for single scattering. The analytical model has been compared to our Monte Carlo simulations as well as to the previous simulations, and good agreements have been achieved. The presented model has potential applications for realistic rendering of transparent and translucent objects.

  17. Teaching Physical Based Animation via OpenGL Slides

    CERN Document Server

    Song, Miao; Grogono, Peter; 10.1145/1557626.1557647

    2009-01-01

    This work expands further our earlier poster presentation and integration of the OpenGL Slides Framework (OGLSF) - to make presentations with real-time animated graphics where each slide is a scene with tidgets - and physical based animation of elastic two-, three-layer softbody objects. The whole project is very interactive, and serves dual purpose - delivering the teaching material in a classroom setting with real running animated examples as well as releasing the source code to the students to show how the actual working things are made.

  18. Results from raw milk microbiological tests do not predict the shelf-life performance of commercially pasteurized fluid milk.

    Science.gov (United States)

    Martin, N H; Ranieri, M L; Murphy, S C; Ralyea, R D; Wiedmann, M; Boor, K J

    2011-03-01

    Analytical tools that accurately predict the performance of raw milk following its manufacture into commercial food products are of economic interest to the dairy industry. To evaluate the ability of currently applied raw milk microbiological tests to predict the quality of commercially pasteurized fluid milk products, samples of raw milk and 2% fat pasteurized milk were obtained from 4 New York State fluid milk processors for a 1-yr period. Raw milk samples were examined using a variety of tests commonly applied to raw milk, including somatic cell count, standard plate count, psychrotrophic bacteria count, ropy milk test, coliform count, preliminary incubation count, laboratory pasteurization count, and spore pasteurization count. Differential and selective media were used to identify groups of bacteria present in raw milk. Pasteurized milk samples were held at 6°C for 21 d and evaluated for standard plate count, coliform count, and sensory quality throughout shelf-life. Bacterial isolates from select raw and pasteurized milk tests were identified using 16S ribosomal DNA sequencing. Linear regression analysis of raw milk test results versus results reflecting pasteurized milk quality consistently showed low R(2) values (milk tests and results from tests used to evaluate pasteurized milk quality. Our findings suggest the need for new raw milk tests that measure the specific biological barriers that limit shelf-life and quality of fluid milk products.

  19. Role of nutritional status in predicting quality of life outcomes in cancer--a systematic review of the epidemiological literature.

    Science.gov (United States)

    Lis, Christopher G; Gupta, Digant; Lammersfeld, Carolyn A; Markman, Maurie; Vashi, Pankaj G

    2012-04-24

    Malnutrition is a significant factor in predicting cancer patients' quality of life (QoL). We systematically reviewed the literature on the role of nutritional status in predicting QoL in cancer. We searched MEDLINE database using the terms "nutritional status" in combination with "quality of life" together with "cancer". Human studies published in English, having nutritional status as one of the predictor variables, and QoL as one of the outcome measures were included. Of the 26 included studies, 6 investigated head and neck cancer, 8 gastrointestinal, 1 lung, 1 gynecologic and 10 heterogeneous cancers. 24 studies concluded that better nutritional status was associated with better QoL, 1 study showed that better nutritional status was associated with better QoL only in high-risk patients, while 1 study concluded that there was no association between nutritional status and QoL. Nutritional status is a strong predictor of QoL in cancer patients. We recommend that more providers implement the American Society of Parenteral and Enteral Nutrition (ASPEN) guidelines for oncology patients, which includes nutritional screening, nutritional assessment and intervention as appropriate. Correcting malnutrition may improve QoL in cancer patients, an important outcome of interest to cancer patients, their caregivers, and families.

  20. Personality traits predict perceived health-related quality of life in persons with multiple sclerosis.

    Science.gov (United States)

    Zarbo, Ignazio Roberto; Minacapelli, Eleonora; Falautano, Monica; Demontis, Silvia; Carpentras, Giovanni; Pugliatti, Maura

    2016-04-01

    Personality traits can affect health-related quality of life (HRQoL) in different disorders. In multiple sclerosis (MS), personality traits can determine patients' willingness to take on more risky treatment options, predispose to neuropsychiatric symptoms and affect coping strategies. We investigated the role of personality traits as possible predictors of HRQoL in a large cohort of persons with MS (PwMS). In total, 253 consecutively recruited PwMS were screened for intellectual deficits with Raven Colour Progressive Matrices (RCPM), state anxiety with STAI-X1 and major depression on a clinical basis. PwMS' self-perceived mental and physical health status was measured with the 36-Item Short Form Health Survey (SF-36), and the personality profile with the Eysenck Personality Questionnaire (EPQ-R). The correlation between HRQoL and personality traits was investigated by means of analysis of variance, adjusting for possible confounders. Of the 253 MS patients, 195 (F:M=2.75), aged 41.7±10.2 years were included in the analysis. The variance of SF-36 mental and physical composite score was largely explained by extraversion and neuroticism. Our data confirm that PwMS' HRQoL is largely influenced by personality traits, which may therefore act as predictors of perceived quality of life and should be included in clinical and experimental settings focusing on HRQoL. © The Author(s), 2015.

  1. An Energy-Critical Plane Based Fatigue Damage Approach for the Life Prediction of Metal Alloys

    Science.gov (United States)

    Pitatzis, N.; Savaidis, G.

    2016-11-01

    This paper presents a new energy-critical plane based fatigue damage approach for the assessment of the fatigue life under uniaxial and multiaxial proportional and non-proportional fatigue loading. The proposed approximate method, based on Farahani's multiaxial fatigue damage model, takes into account the critical plane orientations during a loading cycle and the values of the respective damage parameters on them. The uniqueness of the proposed method lies on the fact that it considers a weighted contribution of each critical plane orientation to the material damage. The relative weighting factors depend on the declination of each critical plane with respect to the critical plane, where the damage parameters exhibit their maximum values during a fatigue loading cycle. Herein, several low, mid and high-cycle fatigue loading cases are being investigated. The induced elastic-plastic stress-strain states are approximated by means of respective finite element analyses (FEA). Several experimental fatigue data derived from uniaxial and multiaxial fatigue tests on StE460 steel alloy thin-walled hourglass-type specimens have been used to verify the model's calculation accuracy. Comparison of experimental and calculated fatigue lives confirm remarkable fatigue life calculation accuracy in all cases examined.

  2. Serum globulin predicts all-cause mortality for life insurance applicants.

    Science.gov (United States)

    Fulks, Michael; Stout, Robert L; Dolan, Vera F

    2014-01-01

    Determine the relative mortality in apparently healthy adults with various levels of serum globulin. By use of the Social Security Death Master File, mortality in 2010 was determined for 7.7 million life insurance applicants age 20 to 89 providing blood samples with valid globulin results between 1992 and 2006. Relative mortality by Cox regression for bands of globulin values was determined by age-sex group, with age split into 20 to 59 and 60 to 89, with each grouping also including age as a covariate. Further analysis was conducted by excluding applicants with elevations of other test values associated with increased globulin levels and mortality risk. After accounting for the mortality impact of frequently associated laboratory test abnormalities including BMI, alkaline phosphatase and albumin, relative mortality was found to increase gradually for globulin values > 3.2 g/dL. Values > 4.0 were associated with a mortality risk that was approximately doubled. There is also a small increased risk for globulin values < 1.9 g/dL. The highest 20% of globulin levels were associated with steadily increasing mortality in life insurance applicants. In many cases, other laboratory findings were not informative of the risk.

  3. Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species.

    Science.gov (United States)

    Young, Emma F; Belchier, Mark; Hauser, Lorenz; Horsburgh, Gavin J; Meredith, Michael P; Murphy, Eugene J; Pascoal, Sonia; Rock, Jennifer; Tysklind, Niklas; Carvalho, Gary R

    2015-06-01

    Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a 'seascape genetics' approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.

  4. Fatigue life prediction using multiaxial energy calculations with the mean stress effect to predict failure of linear and nonlinear elastic solids

    Science.gov (United States)

    Nagode, Marko; Šeruga, Domen

    An approach is presented that enables the calculation of elastic strain energy in linear and nonlinear elastic solids during arbitrary thermomechanical load cycles. The approach uses the simple fact that the variation of both strain and complementary energies always forms a rectangular shape in stress-strain space, hence integration is no longer required to calculate the energy. Furthermore, the approach considers the mean stress effect so that predictions of fatigue damage are more realistically representative of real-life experimental observations. By doing so, a parameter has been proposed to adjust the mean stress effect. This parameter α is based on the well-known Smith-Watson-Topper energy criterion, but allows consideration of other arbitrary mean stress effects, e.g. the Bergmann type criterion. The approach has then been incorporated into a numerical method which can be applied to uniaxial and multiaxial, proportional and non-proportional loadings to predict fatigue damage. The end result of the method is the cyclic evolution of accumulated damage. Numerical examples show how the method presented in this paper could be applied to a nonlinear elastic material.

  5. Physics-based gene identification: proof of concept for Plasmodium falciparum.

    Science.gov (United States)

    Yeramian, Edouard; Bonnefoy, Serge; Langsley, Gordon

    2002-01-01

    The ab initio prediction of new genes in eukaryotic genomes represents a difficult task, notably for the identification of complex split genes. A Physics-Based Gene Identification (PBGI) method was formulated recently (Yeramian, Gene, 255, 139-150, 151-168, 2000a,b) to address this problem, taking as a model the Plasmodium falciparum genome. Here, the predictive power of this method is put under experimental test for this genome. The presented results demonstrate the usefulness of the PBGI as a gene-identification tool for P. falciparum, notably for the discovery of new genes with no homology to known genes. Perspectives opened by this new method for other eukaryotic genomes are also mentioned.

  6. Sex differences in cognitive ageing: testing predictions derived from life-history theory in a dioecious nematode.

    Science.gov (United States)

    Zwoinska, Martyna K; Kolm, Niclas; Maklakov, Alexei A

    2013-12-01

    Life-history theory maintains that organisms allocate limited resources to different traits to maximize fitness. Learning ability and memory are costly and known to trade-off with longevity in invertebrates. However, since the relationship between longevity and fitness often differs between the sexes, it is likely that sexes will differentially resolve the trade-off between learning and longevity. We used an established associative learning paradigm in the dioecious nematode Caenorhabditis remanei, which is sexually dimorphic for lifespan, to study age-related learning ability in males and females. In particular, we tested the hypothesis that females (the shorter-lived sex) show higher learning ability than males early in life but senesce faster. Indeed, young females outperformed young males in learning a novel association between an odour (butanone) and food (bacteria). However, while learning ability and offspring production declined rapidly with age in females, males maintained high levels of these traits until mid-age. These results not only demonstrate sexual dimorphism in age-related learning ability but also suggest that it conforms to predictions derived from the life-history theory.

  7. Clinical and psychosocial factors predicting health-related quality of life in hemodialysis patients.

    Science.gov (United States)

    Kang, Gun Woo; Lee, In Hee; Ahn, Ki Sung; Lee, Jonghun; Ji, Yunmi; Woo, Jungmin

    2015-07-01

    Many patients with end-stage renal disease have significant impairment in health-related quality of life (HRQoL). Most previous studies have focused on clinical factors; however, quality of life can also be affected by psychosocial factors. The aim of this study was to identify the possible predictors of HRQoL among clinical and psychosocial factors in hemodialysis (HD) patients. The study included 101 patients who were undergoing HD. Psychosocial factors were evaluated using the Hospital Anxiety and Depression Scale, Multidimensional Scale of Perceived Social Support, Montreal Cognitive Assessment, and Pittsburgh Sleep Quality Index. We also assessed laboratory and clinical factors, including albumin, Kt/V as a marker of dialysis adequacy, normalized protein catabolic rate, and duration of HD. The Euro Quality of Life Questionnaire 5-Dimensional Classification (EQ-5D) was used to evaluate HRQoL. The mean EQ-5D index score was 0.704 ± 0.199. The following variables showed a significant association with the EQ-5D index: age (P < 0.001), depression (P < 0.001), anxiety (P < 0.001), support from friends (P < 0.001), cognitive function (P < 0.001), duration of HD (P = 0.034), triglyceride (P = 0.031), total iron-binding capacity (P = 0.036), and phosphorus (P = 0.037). Multiple regression analysis showed that age (95% confidence interval [CI] -0.008 to -0.002), anxiety (95% CI -0.025 to -0.009), and support from friends (95% CI 0.004 to 0.018) were independent predictors of impaired HRQoL. This study explored determinants of impaired HRQoL in HD patients. We found that impaired HRQoL was independently associated with age, anxiety, and support from friends. We should consider psychosocial as well as clinical factors when evaluating ways to improve HRQoL in HD patients.

  8. MRI-Based Classification Models in Prediction of Mild Cognitive Impairment and Dementia in Late-Life Depression

    Science.gov (United States)

    Lebedeva, Aleksandra K.; Westman, Eric; Borza, Tom; Beyer, Mona K.; Engedal, Knut; Aarsland, Dag; Selbaek, Geir; Haberg, Asta K.

    2017-01-01

    Objective: Late-life depression (LLD) is associated with development of different types of dementia. Identification of LLD patients, who will develop cognitive decline, i.e., the early stage of dementia would help to implement interventions earlier. The purpose of this study was to assess whether structural brain magnetic resonance imaging (MRI) in LLD patients can predict mild cognitive impairment (MCI) or dementia 1 year prior to the diagnosis. Methods: LLD patients underwent brain MRI at baseline and repeated clinical assessment after 1-year. Structural brain measurements were obtained using Freesurfer software (v. 5.1) from the T1W brain MRI images. MRI-based Random Forest classifier was used to discriminate between LLD who developed MCI or dementia after 1-year follow-up and cognitively stable LLD. Additionally, a previously established Random Forest model trained on 185 patients with Alzheimer’s disease (AD) vs. 225 cognitively normal elderly from the Alzheimer’s disease Neuroimaging Initiative was tested on the LLD data set (ADNI model). Results: MCI and dementia diagnoses were predicted in LLD patients with 76%/68%/84% accuracy/sensitivity/specificity. Adding the baseline Mini-Mental State Examination (MMSE) scores to the models improved accuracy/sensitivity/specificity to 81%/75%/86%. The best model predicted MCI status alone using MRI and baseline MMSE scores with accuracy/sensitivity/specificity of 89%/85%/90%. The most important region for all the models was right ventral diencephalon, including hypothalamus. Its volume correlated negatively with the number of depressive episodes. ADNI model trained on AD vs. Controls using SV could predict MCI-DEM patients with 67% accuracy. Conclusion: LDD patients developing MCI and dementia can be discriminated from LLD patients remaining cognitively stable with good accuracy based on baseline structural MRI alone. Baseline MMSE score improves prediction accuracy. Ventral diencephalon, including the hypothalamus

  9. Do early-life conditions predict functional health status in adulthood? The case of Mexico.

    Science.gov (United States)

    Huang, Cheng; Soldo, Beth J; Elo, Irma T

    2011-01-01

    Relatively few researchers have investigated early antecedents of adult functional limitations in developing countries. In this study, we assessed associations between childhood conditions and adult lower-body functional limitations (LBFL) as well as the potential mediating role of adult socioeconomic status, smoking, body mass index, and chronic diseases or symptoms. Based on data from the Mexican Health and Aging Study (MHAS) of individuals born prior to 1951 and contacted in 2001 and 2003, we found that childhood nutritional deprivation, serious health problems, and family background predict adult LBFL in Mexico. Adjustment for the potential mediators in adulthood attenuates these associations only to a modest degree.

  10. Predictive value of familiality, stressful life events and gender on the course of obsessive-compulsive disorder.

    Science.gov (United States)

    Goldberg, Ximena; Soriano-Mas, Carles; Alonso, Pino; Segalàs, Cinto; Real, Eva; López-Solà, Clara; Subirà, Marta; Via, Esther; Jiménez-Murcia, Susana; Menchón, José M; Cardoner, Narcís

    2015-10-01

    Familiality, stressful life events (SLE) and gender significantly affect the onset of obsessive-compulsive disorder (OCD). However, their combined impact on the probability of OCD chronicity is largely unknown. With the objective of clarifying their predictive value, we tested a model of interaction effects between these influences. A sample of 449 patients with OCD was systematically assessed for familial loading, exposure to stressful life events, gender and course of the disease at the OCD referral unit at Bellvitge University Hospital. Multiple ordinal logistic regression was used to test interaction models. Familiality presented a main negative association with chronicity (OR=0.83, CI97.5%=0.70-0.98). This association was additively moderated by both exposure to SLE before onset and gender, and showed a positive slope among female patients not exposed to SLE before onset (Familiality*SLEbo: OR=0.69, CI97.5%=0.47-1; Familiality*gender: OR=1.30, CI97.5%=0.91-1.84). The findings are based on cross-sectional data. Assessment of course is based on a retrospective measure, which may imply the possibility of overestimation of chronicity. The predictive value of familiality on the course of OCD is only partially informative as both SLEbo and gender modify the association. When other risk factors are included in the model, familiality may predict decreased chances of chronicity. The mediation effects identified could explain the discrepancies found in previous research on this topic. Increased chances of presenting a chronic course of OCD may be found in association with familial vulnerability among female patients not exposed to SLEbo. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. A criterion for high-cycle fatigue life and fatigue limit prediction in biaxial loading conditions

    Institute of Scientific and Technical Information of China (English)

    ukasz Pejkowski; Dariusz Skibicki

    2016-01-01

    This paper presents a criterion for high-cycle fatigue life and fatigue strength estimation under periodic proportional and non-proportional cyclic loading. The cri-terion is based on the mean and maximum values of the second invariant of the stress deviator. Important elements of the criterion are: function of the non-proportionality of fatigue loading and the materials parameter that expresses the materials sensitivity to non-proportional loading. The methods for the materials parameters determination uses three S–N curves: tension–compression, torsion, and any non-proportional loading proposed. The criterion has been verified using experimental data, and the results are included in the paper. These results should be considered as promis-ing. The paper also includes a proposal for multiaxial fatigue models classification due to the approach for the non-proportionality of loading.

  12. Prediction of material creep behaviour for strain based life assessment applications

    Energy Technology Data Exchange (ETDEWEB)

    Rantala, J.H.; Hurst, R.C. [EC JRC IAM, Petten (Netherlands); Bregani, F. [ENEL, Milan (Italy)

    1998-12-31

    In this work the idea of using constant load uniaxial creep test results instead of constant stress results for developing a CDM creep model for the P92 material is demonstrated. Due to limited availability of creep test results this work is based on incomplete test data and a general stress rupture line. In spite of these limitations a material creep model was developed for use in a FE analysis. Using P91 material as an example, a method is proposed to account for differences in strain evolution as a function of stress which normally manifests itself as lower strain values at low stresses in a normalised time-strain plot. This allows the CDM model to be used both in FE analysis and in strain-based life assessment engineering calculations. (orig.) 3 refs.

  13. Interviews with children who experienced major life stress: family and child attributes that predict resilient outcomes.

    Science.gov (United States)

    Wyman, P A; Cowen, E L; Work, W C; Raoof, A; Gribble, P A; Parker, G R; Wannon, M

    1992-09-01

    Demographically comparable groups of children exposed to major life-stress, with stress resilient (SR) and stress affected (SA) outcomes at ages 10 to 12, were interviewed to assess perceptions of their caregiving environments, peer relationships, and themselves. SR children compared with SA children reported more: (1) positive relationships with primary caregivers, (2) stable family environments, (3) inductive and consistent family discipline practices, and (4) positive expectations for their futures. SR girls viewed their mothers as more nurturing than did SA girls. Perceptions of fathers, quality of peer relationships, and global self-concept did not differentiate the groups. A discriminant function analysis identified four variables that correctly classified 74% of the subjects as SR or SA. Findings support the view that caregiver-child relationships play a key role in moderating children's developmental outcomes under conditions of high stress.

  14. Bayesian Models for Life Prediction and Fault-Mode Classification in Solid State Lamps

    Energy Technology Data Exchange (ETDEWEB)

    Lall, Pradeep; Wei, Junchao; Sakalaukus, Peter

    2015-04-19

    A new method has been developed for assessment of the onset of degradation in solid state luminaires to classifY failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identifY luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. It is expected that, the new test technique will allow the development of failure distributions without testing till L 70 life for the manifestation of failure.

  15. Life Prediction and Classification of Failure Modes in Solid State Luminaires Using Bayesian Probabilistic Models

    Energy Technology Data Exchange (ETDEWEB)

    Lall, Pradeep; Wei, Junchao; Sakalaukus, Peter

    2014-05-27

    A new method has been developed for assessment of the onset of degradation in solid state luminaires to classify failure mechanisms by using metrics beyond lumen degradation that are currently used for identification of failure. Luminous Flux output, Correlated Color Temperature Data on Philips LED Lamps has been gathered under 85°C/85%RH till lamp failure. The acquired data has been used in conjunction with Bayesian Probabilistic Models to identify luminaires with onset of degradation much prior to failure through identification of decision boundaries between lamps with accrued damage and lamps beyond the failure threshold in the feature space. In addition luminaires with different failure modes have been classified separately from healthy pristine luminaires. It is expected that, the new test technique will allow the development of failure distributions without testing till L70 life for the manifestation of failure.

  16. Preadmission quality of life can predict mortality in intensive care unit—A prospective cohort study

    DEFF Research Database (Denmark)

    Bukan, Ramin I; Møller, Ann M; Henning, Mattias A S

    2014-01-01

    PURPOSE: We sought to investigate whether preadmission quality of life could act as a predictor of mortality among patients admitted to the intensive care unit (ICU). MATERIALS AND METHODS: This is a prospective observational study of all patients above the age of 18 years admitted to the ICU...... regarding ICU admission and deserves more attention by those caring for critically ill patients....... with a length of stay longer than 24 hours. Short form 36 (SF-36) and Acute Physiology and Chronic Health Evaluation II (APACHE II) were used. Mortality was assessed during ICU admission, 30, and 90 days hereafter. RESULTS: We included 318 patients. No patients were lost to follow-up. Using the physical...

  17. A Modified Fatigue Damage Model for High-Cycle Fatigue Life Prediction

    Directory of Open Access Journals (Sweden)

    Meng Wang

    2016-01-01

    Full Text Available Based on the assumption of quasibrittle failure under high-cycle fatigue for the metal material, the damage constitutive equation and the modified damage evolution equation are obtained with continuum damage mechanics. Then, finite element method (FEM is used to describe the failure process of metal material. The increment of specimen’s life and damage state can be researched using damage mechanics-FEM. Finally, the lifetime of the specimen is got at the given stress level. The damage mechanics-FEM is inserted into ABAQUS with subroutine USDFLD and the Python language is used to simulate the fatigue process of titanium alloy specimens. The simulation results have a good agreement with the testing results under constant amplitude loading, which proves the accuracy of the method.

  18. A methodology for physically based rockfall hazard assessment

    Directory of Open Access Journals (Sweden)

    G. B. Crosta

    2003-01-01

    Full Text Available Rockfall hazard assessment is not simple to achieve in practice and sound, physically based assessment methodologies are still missing. The mobility of rockfalls implies a more difficult hazard definition with respect to other slope instabilities with minimal runout. Rockfall hazard assessment involves complex definitions for "occurrence probability" and "intensity". This paper is an attempt to evaluate rockfall hazard using the results of 3-D numerical modelling on a topography described by a DEM. Maps portraying the maximum frequency of passages, velocity and height of blocks at each model cell, are easily combined in a GIS in order to produce physically based rockfall hazard maps. Different methods are suggested and discussed for rockfall hazard mapping at a regional and local scale both along linear features or within exposed areas. An objective approach based on three-dimensional matrixes providing both a positional "Rockfall Hazard Index" and a "Rockfall Hazard Vector" is presented. The opportunity of combining different parameters in the 3-D matrixes has been evaluated to better express the relative increase in hazard. Furthermore, the sensitivity of the hazard index with respect to the included variables and their combinations is preliminarily discussed in order to constrain as objective as possible assessment criteria.

  19. Does health-related quality of lifepredict injury event?‎

    Directory of Open Access Journals (Sweden)

    Kambiz Abachizadeh

    2009-07-01

    Full Text Available Background: Unintentional injury is a leading threat to children's health. Some human ‎factors have been determined as predictor of unintentional injury. Association ‎between Health-Related Quality of Life (HRQOL as a human factor and unintentional ‎injuries is unclear. The objective of study is to examine the association between ‎HRQOL and unintentional injuries among primary school children. Methods: This study was a cross-sectional conducted in Ahwaz, a city in Iran. ‎Overall, 3375 children aged 6-10 years were randomly selected from primary school. ‎HRQOL was measured by 56 items taken from seven domains of Netherlands ‎Organization for Applied Scientific Research Academic Medical Center (TNO AZL ‎child quality of life (TACQOL parent form. Parents were interviewed to collect ‎information about incidence, cause and a brief description of injury within the past 12 ‎months prior to the study.‎ Results: The response rate was 3375 of 3792 (89%. There was a significant trend ‎for increasing occurrence of injury with decreasing of HRQOL score (P= Sig. ‎Adjusted OR for injury was significantly higher in very low (2.38, 95% CI: 1.45-‎‎3.86, low (2.18, 95% CI: 1.34-3.56, and medium (1.73, 95%CI: 1.06-2.83 ‎HRQOL groups compared to reference group (very high HRQOL. The median of total ‎HRQOL (P= Sig and all its domains (P=0.017 (except autonomous functioning ‎was lower in injured group compared to uninjured one.‎ Conclusions: This study found an association between HRQOL and unintentional ‎injury among primary school children. This is a preliminary finding and further ‎investigations with a well-defined analytical design are needed.‎

  20. Predictive Models for Tomato Spotted Wilt Virus Spread Dynamics, Considering Frankliniella occidentalis Specific Life Processes as Influenced by the Virus.

    Science.gov (United States)

    Ogada, Pamella Akoth; Moualeu, Dany Pascal; Poehling, Hans-Michael

    2016-01-01

    Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant), as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV) in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.

  1. BDNF Val66Met genotype and neuroticism predict life stress: A longitudinal study from childhood to adulthood.

    Science.gov (United States)

    Lehto, Kelli; Mäestu, Jarek; Kiive, Evelyn; Veidebaum, Toomas; Harro, Jaanus

    2016-03-01

    The brain-derived neurotrophic factor gene (BDNF) Val66Met polymorphism and life stress have been associated with negative emotionality (e.g., neuroticism), but relevant evidence is far from unequivocal. Possible confounding factors include the type and timing of stressful events measured, such as childhood adversity vs. recent stressful events, and variable gene × environment interactions. The aim of this study was to longitudinally assess the BDNF Val66Met polymorphism and environment interaction effect on neuroticism in a population representative sample, depending upon the type of stress, gender and family relations. In the original older cohort of the Estonian Children Personality Behavior and Health Study (ECPBHS, n=593), neuroticism was measured at age 15 (parental assessment), 18 and 25 (self-assessments). Childhood stress was reported at age 15, quality of family relations was measured at age 18, and recent stressful life events at age 25. The BDNF Val66Met polymorphism interacted with recent stressful life events, but not with childhood adversities, to impact neuroticism. Interestingly, in female participants, neuroticism at age 18 predicted future stressful life events dependent upon genotype: individuals with Val/Val genotype and high neuroticism experienced higher, but Met-allele carriers with high neuroticism lower stress exposure at age 25. Similar tendencies were observed using parental assessments at age 15. The protective effect of Met-allele in the high stress exposure group could result from better early family environment. In conclusion, we herewith provide further evidence for a role of BDNF gene variance contributing to plasticity in response to environmental demands.

  2. Predictive Models for Tomato Spotted Wilt Virus Spread Dynamics, Considering Frankliniella occidentalis Specific Life Processes as Influenced by the Virus.

    Directory of Open Access Journals (Sweden)

    Pamella Akoth Ogada

    Full Text Available Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant, as well as their interactions with the environment. A large body of studies mainly focuses on weather based models as management tool for monitoring pests and diseases, with very few incorporating the contribution of vector's life processes in the disease dynamics, which is an essential aspect when mitigating virus incidences in a crop stand. In this study, we hypothesized that the multiplication and spread of tomato spotted wilt virus (TSWV in a crop stand is strongly related to its influences on Frankliniella occidentalis preferential behavior and life expectancy. Model dynamics of important aspects in disease development within TSWV-F. occidentalis-host plant interactions were developed, focusing on F. occidentalis' life processes as influenced by TSWV. The results show that the influence of TSWV on F. occidentalis preferential behaviour leads to an estimated increase in relative acquisition rate of the virus, and up to 33% increase in transmission rate to healthy plants. Also, increased life expectancy; which relates to improved fitness, is dependent on the virus induced preferential behaviour, consequently promoting multiplication and spread of the virus in a crop stand. The development of vector-based models could further help in elucidating the role of tri-trophic interactions in agricultural disease systems. Use of the model to examine the components of the disease process could also boost our understanding on how specific epidemiological characteristics interact to cause diseases in crops. With this level of understanding we can efficiently develop more precise control strategies for the virus and the vector.

  3. Becoming popular: Interpersonal emotion regulation predicts relationship formation in real life social networks

    Directory of Open Access Journals (Sweden)

    Karen eNiven

    2015-09-01

    Full Text Available Building relationships is crucial for satisfaction and success, especially when entering new social contexts. In the present paper, we investigate whether attempting to improve others’ feelings helps people to make connections in new networks. In Study 1, a social network study following new networks of people for a twelve-week period indicated that use of interpersonal emotion regulation (IER strategies predicted growth in popularity, as indicated by other network members’ reports of spending time with the person, in work and non-work interactions. In Study 2, linguistic analysis of the tweets from over 8000 Twitter users from formation of their accounts revealed that use of IER predicted greater popularity in terms of the number of followers gained. However, not all types of IER had positive effects. Behavioral IER strategies (which use behavior to reassure or comfort in order to regulate affect were associated with greater popularity, while cognitive strategies (which change a person’s thoughts about his or her situation or feelings in order to regulate affect were negatively associated with popularity. Our findings have implications for our understanding of how new relationships are formed, highlighting the important the role played by intentional emotion regulatory processes.

  4. Becoming popular: interpersonal emotion regulation predicts relationship formation in real life social networks.

    Science.gov (United States)

    Niven, Karen; Garcia, David; van der Löwe, Ilmo; Holman, David; Mansell, Warren

    2015-01-01

    Building relationships is crucial for satisfaction and success, especially when entering new social contexts. In the present paper, we investigate whether attempting to improve others' feelings helps people to make connections in new networks. In Study 1, a social network study following new networks of people for a 12-week period indicated that use of interpersonal emotion regulation (IER) strategies predicted growth in popularity, as indicated by other network members' reports of spending time with the person, in work and non-work interactions. In Study 2, linguistic analysis of the tweets from over 8000 Twitter users from formation of their accounts revealed that use of IER predicted greater popularity in terms of the number of followers gained. However, not all types of IER had positive effects. Behavioral IER strategies (which use behavior to reassure or comfort in order to regulate affect) were associated with greater popularity, while cognitive strategies (which change a person's thoughts about his or her situation or feelings in order to regulate affect) were negatively associated with popularity. Our findings have implications for our understanding of how new relationships are formed, highlighting the important the role played by intentional emotion regulatory processes.

  5. Illness perceptions of adults with congenital heart disease and their predictive value for quality of life two years later.

    Science.gov (United States)

    Schoormans, Dounya; Mulder, Barbara J M; van Melle, Joost P; Pieper, Petronella G; van Dijk, Arie P J; Sieswerda, Gertjan Tj; Hulsbergen-Zwarts, Mariët S; Plokker, Thijs H W M; Brunninkhuis, Leo G H; Vliegen, Hubert W; Sprangers, Mirjam A G

    2014-02-01

    To improve patients' quality of life (QoL) we need to identify modifiable determinants, such as illness perceptions. Patients' illness perceptions are known to regulate emotional responses and health-behaviour. Illness perceptions comprise several components: consequences, control, coherence, changeability and emotional representations. To examine (a) the relation between patient characteristics and illness perceptions, and (b) the independent predictive value of illness perceptions for future QoL. A longitudinal study in 845 patients with congenital heart disease was conducted. Patients completed three questionnaires: the IPQ-R (illness perceptions) and two years later the SF-36 and TAAQOL-CHD (QoL). Linear regression analyses were performed relating illness perceptions to patient characteristics (sex, age, disease complexity and functional status) and QoL. Patients with a complex defect or poor functional status reported poor illness perceptions. Independent of patient characteristics, poor illness perceptions (i.e. a strong belief that the illness has severe consequences; a weak belief that you have a coherent illness understanding and that the illness can be controlled by treatment; and a strong belief that the illness is changeable and causes negative emotions) were predictive of future QoL. Illness perceptions independently predict QoL, suggesting that QoL may be improved by altering patients' beliefs about their illness. For example, increasing patients' knowledge regarding their disease and informing them about treatment opportunities may enhance their QoL.

  6. Predicting the occurrence, conviction, distress, and disruption of different delusional experiences in the daily life of people with schizophrenia.

    Science.gov (United States)

    Ben-Zeev, Dror; Morris, Scott; Swendsen, Joel; Granholm, Eric

    2012-06-01

    Recent research has shown that negative emotional states of increased anxiety and sadness prospectively predict the occurrence of persecutory ideation, but it is not known whether these findings extend to other subtypes of delusions. The current study explored whether these negative emotional states, as well as hallucinations, biased reasoning style (ie, jumping to conclusions), and negative self-esteem prospectively predict the occurrence and various dimensions of delusions of control, reference, and grandiosity in real time, as they occur in daily life. One hundred and thirty community-dwelling participants with schizophrenia or schizoaffective disorder completed laboratory measures and momentary self-reports generated by a personal digital assistant multiple times per day, over 7 consecutive days. Analyses were time lagged allowing simultaneous examination of person-level and within-person time-varying relationships among the variables. Approximately, half of the participants reported having at least one delusional experience during the week, and approximately, a quarter of those individuals reported experiencing all 3 delusion subtypes. Hallucinations were a significant predictor of the occurrence of delusions of control and reference over the subsequent hours of the same day, but negative emotional states of anxiety and sadness were not. Negative self-esteem predicted the frequency of all 3 delusion subtypes during the week, and a reasoning style characterized by reduced information gathering was a significant predictor of the frequency of delusions of control. Delusional dimensions of conviction, distress, and disruption had different associations with the variables tested for each delusion subtype.

  7. High-temperature fatigue in metals - A brief review of life prediction methods developed at the Lewis Research Center of NASA

    Science.gov (United States)

    Halford, G. R.

    1983-01-01

    The presentation focuses primarily on the progress we at NASA Lewis Research Center have made. The understanding of the phenomenological processes of high temperature fatigue of metals for the purpose of calculating lives of turbine engine hot section components is discussed. Improved understanding resulted in the development of accurate and physically correct life prediction methods such as Strain-Range partitioning for calculating creep fatigue interactions and the Double Linear Damage Rule for predicting potentially severe interactions between high and low cycle fatigue. Examples of other life prediction methods are also discussed. Previously announced in STAR as A83-12159

  8. Uric acid measurement improves prediction of cardiovascular mortality in later life.

    Science.gov (United States)

    Dutta, Ambarish; Henley, William; Pilling, Luke C; Wallace, Robert B; Melzer, David

    2013-03-01

    To estimate the association between uric acid and cardiovascular mortality in older adults, independent of traditional risk factors, and to estimate the risk prediction gain by adding uric acid measurements to the Framingham Cardiovascular Risk Score (FCRS). Longitudinal observational study of two population-based cohorts. The Established Populations for Epidemiologic Studies of the Elderly, Iowa (Iowa-EPESE) and the Third National Health and Nutritional Examination Survey (NHANES III). One thousand twenty-eight Iowa-EPESE participants and 1,316 NHANES III participants. Selected participants were aged 70 and older without overt cardiovascular disease, renal dysfunction, or diuretic use who lived for 3 years or longer after baseline. Outcome was age at cardiovascular death during follow-up (12–20 years). Uric acid and cardiovascular risk factors such as smoking, systolic blood pressure, diabetes mellitus, obesity, serum cholesterol, and high-density lipoprotein cholesterol were measured at baseline. High serum uric acid (>7.0 mg/dL) was associated with male sex, obesity, lipid levels, and estimated glomerular filtration rate at baseline. Fully adjusted hazard ratios (HRs) for cardiovascular death with high uric acid versus normal were 1.36 (95% confidence interval (CI) = 1.10–1.69) in Iowa-EPESE and 1.43 (95% CI = 1.04–1.99) in NHANES III; pooled HR was 1.38 (95% CI = 1.16–1.61). The net reclassification improvement achieved by adding uric acid measurement to the FCRS was 9% to 20%. In individuals aged 70 and older without overt CVD, renal dysfunction, or diuretic use, serum uric acid greater than 7.0 mg/dL was associated with greater CVD mortality independent of classic CVD risk factors. Adding uric acid measurement to the FCRS would improve prediction in older adults.

  9. Service-life prediction of reinforced concrete structures in subsurface environment

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ki Jung; Jung, Hae Ryong; Park, Joo Wan [Korea Radioactive Waste Agency, Daejeon (Korea, Republic of)

    2016-03-15

    This paper focuses on the estimation of durability and service-life of reinforced concrete structures in Wolsong Low- and intermediate-level wastes Disposal Center (WLDC) in Korea. There are six disposal silos located in the saturated environment. The silo concrete is degraded due to reactions with groundwater and chemical attacks, and finally it will lose its properties as a transport barrier. The infiltration of sulfate and magnesium, leaching of potassium hydroxide, and chlorine induced corrosion are the most significant factors for degradation of reinforced concrete structure in underground environment. From the result of evaluation of the degradation time for each factor, the degradation rate of the reinforced concrete due to sulfate and magnesium is 1.308×10{sup -3} cm/yr, and it is estimated to take 48,000 years for full degradation while potassium hydroxide is leached in depth of less than 1.5 cm at 1,000 years after the initiation of degradation. In case of chlorine induced corrosion, it takes 1,648 years to initiate corrosion in the main reinforced bar and 2,288 years to reach the lifetime limit of the structural integrity, and thus it is evaluated as the most significant factor.

  10. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures.

    Science.gov (United States)

    Angst, Ueli M; Elsener, Bernhard

    2017-08-01

    Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation (Ccrit). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that Ccrit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable Ccrit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of Ccrit. It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform Ccrit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures.

  11. Perceptual Negativity Predicts Greater Reactivity to Negative Events in Daily Life.

    Science.gov (United States)

    Robinson, Michael D; Liu, Tianwei

    2013-11-01

    Reinforcement sensitivity theory includes the idea that people differ in their sensitivity to negative events, but relevant process-based assessments have not been developed. The present studies assessed sensitivity to negative events in terms of the extent to which negative word stimuli were perceived to be larger than neutral word stimuli. There was a general tendency to overestimate the size of negative relative to neutral words, but individuals differed substantially in this form of what is termed perceptual negativity. Of more importance, two studies (total N = 151) found systematic relationships between individual differences in perceptual negativity and reactivity to negative events in daily diary protocols. Study 1 found that within-person variations in the occurrence of daily negative events undermined goal-related optimism to a greater extent at higher, relative to lower, levels of perceptual negativity. Study 2 conceptually replicated this interaction in the context of within-person associations between the occurrence of daily negative events and antisocial behavior. These findings are important in advancing reinforcement sensitivity theory, in operationalizing a particular component of it, and in extending it to reactivity processes in daily life.

  12. The size effect in corrosion greatly influences the predicted life span of concrete infrastructures

    Science.gov (United States)

    Angst, Ueli M.; Elsener, Bernhard

    2017-01-01

    Forecasting the life of concrete infrastructures in corrosive environments presents a long-standing and socially relevant challenge in science and engineering. Chloride-induced corrosion of reinforcing steel in concrete is the main cause for premature degradation of concrete infrastructures worldwide. Since the middle of the past century, this challenge has been tackled by using a conceptual approach relying on a threshold chloride concentration for corrosion initiation (Ccrit). All state-of-the-art models for forecasting chloride-induced steel corrosion in concrete are based on this concept. We present an experiment that shows that Ccrit depends strongly on the exposed steel surface area. The smaller the tested specimen is, the higher and the more variable Ccrit becomes. This size effect in the ability of reinforced concrete to withstand corrosion can be explained by the local conditions at the steel-concrete interface, which exhibit pronounced spatial variability. The size effect has major implications for the future use of the common concept of Ccrit. It questions the applicability of laboratory results to engineering structures and the reproducibility of typically small-scale laboratory testing. Finally, we show that the weakest link theory is suitable to transform Ccrit from small to large dimensions, which lays the basis for taking the size effect into account in the science and engineering of forecasting the durability of infrastructures. PMID:28782038

  13. Physics-based features for identifying contextual factors affecting landmine detection with ground-penetrating radar

    Science.gov (United States)

    Ratto, Christopher R.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    It has been established throughout the ground-penetrating radar (GPR) literature that environmental factors can severely impact the performance of GPR sensors in landmine detection applications. Over the years, electromagnetic inversion techniques have been proposed for determining these factors with the goal of mitigating performance losses. However, these techniques are often computationally expensive and require models and responses from canonical targets, and therefore may not be appropriate for real-time route-clearance applications. An alternative technique for mitigating performance changes due to environmental factors is context-dependent classification, in which decision rules are adjusted based on contextual shifts identified from the GPR data. However, analysis of the performance of context-dependent learning has been limited to qualitative comparisons of contextually-similar GPR signatures and quantitative improvement to the ROC curve, while the actual information extracted regarding soils has not been investigated thoroughly. In this work, physics-based features of GPR data used in previous context-dependent approaches were extracted from simulated GPR data generated through Finite-Difference Time-Domain (FDTD) modeling. Statistical techniques where then used to predict several potential contextual factors, including soil dielectric constant, surface roughness, amount of subsurface clutter, and the existence of subsurface layering, based on the features. Results suggest that physics-based features of the GPR background may contain informatin regarding physical properties of the environment, and contextdependent classification based on these features can exploit information regarding these potentially-important environmental factors.

  14. Comparisons between physics-based, engineering, and statistical learning models for outdoor sound propagation.

    Science.gov (United States)

    Hart, Carl R; Reznicek, Nathan J; Wilson, D Keith; Pettit, Chris L; Nykaza, Edward T

    2016-05-01

    Many outdoor sound propagation models exist, ranging from highly complex physics-based simulations to simplified engineering calculations, and more recently, highly flexible statistical learning methods. Several engineering and statistical learning models are evaluated by using a particular physics-based model, namely, a Crank-Nicholson parabolic equation (CNPE), as a benchmark. Narrowband transmission loss values predicted with the CNPE, based upon a simulated data set of meteorological, boundary, and source conditions, act as simulated observations. In the simulated data set sound propagation conditions span from downward refracting to upward refracting, for acoustically hard and soft boundaries, and low frequencies. Engineering models used in the comparisons include the ISO 9613-2 method, Harmonoise, and Nord2000 propagation models. Statistical learning methods used in the comparisons include bagged decision tree regression, random forest regression, boosting regression, and artificial neural network models. Computed skill scores are relative to sound propagation in a homogeneous atmosphere over a rigid ground. Overall skill scores for the engineering noise models are 0.6%, -7.1%, and 83.8% for the ISO 9613-2, Harmonoise, and Nord2000 models, respectively. Overall skill scores for the statistical learning models are 99.5%, 99.5%, 99.6%, and 99.6% for bagged decision tree, random forest, boosting, and artificial neural network regression models, respectively.

  15. Coupling on the northern Cascadia subduction zone from geodetic measurements and physics-based models

    Science.gov (United States)

    Bruhat, Lucile; Segall, Paul

    2016-11-01

    Kinematic inversions of GPS and tide gauge/leveling data display an unresolved "gap" between the downdip limit of the locked megathrust and the top of the episodic tremor and slip (ETS) zone in northern Cascadia. This work combines physics-based models of slow-slip events with both mean ETS displacements and decadal-averaged deformation rates to explain the gap and determine how interseismic stress accumulates on the megathrust. While physics-based predictions match the average ETS displacements, they significantly misfit long-term rates, implying faster slip rates within both the gap and the ETS region. Heterogeneous Green's functions or velocity-strengthening friction within the gap cannot explain the decadal rates. The observed uplift rates require steeper gradients in slip rate at the base of the locked zone. We invert for the smallest possible shear stress rate on the creeping megathrust below a locked zone that satisfactorily fits the data. A nonzero shear stress rate within the ETS zone, reaching -2.5 kPa/yr at a depth of 25-30 km, is required. Finally, of all the models that adequately fit both horizontal and vertical data, only those with deep locking depths, around 21 km, significantly improve the fit to the uplift rates.

  16. Rethinking earthquake-related DC-ULF electromagnetic phenomena: towards a physics-based approach

    Directory of Open Access Journals (Sweden)

    Q. Huang

    2011-11-01

    Full Text Available Numerous electromagnetic changes possibly related with earthquakes have been independently reported and have even been attempted to apply to short-term prediction of earthquakes. However, there are active debates on the above issue because the seismogenic process is rather complicated and the studies have been mainly empirical (i.e. a kind of experience-based approach. Thus, a physics-based study would be helpful for understanding earthquake-related electromagnetic phenomena and strengthening their applications. As a potential physics-based approach, I present an integrated research scheme, taking into account the interaction among observation, methodology, and physical model. For simplicity, this work focuses only on the earthquake-related DC-ULF electromagnetic phenomena. The main approach includes the following key problems: (1 how to perform a reliable and appropriate observation with some clear physical quantities; (2 how to develop a robust methodology to reveal weak earthquake-related electromagnetic signals from noisy background; and (3 how to develop plausible physical models based on theoretical analyses and/or laboratory experiments for the explanation of the earthquake-related electromagnetic signals observed in the field conditions.

  17. Perceiving social pressure not to feel negative predicts depressive symptoms in daily life.

    Science.gov (United States)

    Dejonckheere, Egon; Bastian, Brock; Fried, Eiko I; Murphy, Sean C; Kuppens, Peter

    2017-09-01

    Western societies often overemphasize the pursuit of happiness, and regard negative feelings such as sadness or anxiety as maladaptive and unwanted. Despite this emphasis on happiness, the amount of people suffering from depressive complaints is remarkably high. To explain this apparent paradox, we examined whether experiencing social pressure not to feel sad or anxious could in fact contribute to depressive symptoms. A sample of individuals (n = 112) with elevated depression scores (Patient Health Questionnaire [PHQ-9] ≥ 10) took part in an online daily diary study in which they rated their depressive symptoms and perceived social pressure not to feel depressed or anxious for 30 consecutive days. Using multilevel VAR models, we investigated the temporal relation between this perceived social pressure and depressive symptoms to determine directionality. Primary analyses consistently indicated that experiencing social pressure predicts increases in both overall severity scores and most individual symptoms of depression, but not vice versa. A set of secondary analyses, in which we adopted a network perspective on depression, confirmed these findings. Using this approach, centrality analysis revealed that perceived social pressure not to feel negative plays an instigating role in depression, reflected by the high out- and low instrength centrality of this pressure in the various depression networks. Together, these findings indicate how perceived societal norms may contribute to depression, hinting at a possible malignant consequence of society's denouncement of negative emotions. Clinical implications are discussed. © 2017 Wiley Periodicals, Inc.

  18. Cortisol in mother's milk across lactation reflects maternal life history and predicts infant temperament.

    Science.gov (United States)

    Hinde, Katie; Skibiel, Amy L; Foster, Alison B; Del Rosso, Laura; Mendoza, Sally P; Capitanio, John P

    2015-01-01

    The maternal environment exerts important influences on offspring mass/growth, metabolism, reproduction, neurobiology, immune function, and behavior among birds, insects, reptiles, fish, and mammals. For mammals, mother's milk is an important physiological pathway for nutrient transfer and glucocorticoid signaling that potentially influences offspring growth and behavioral phenotype. Glucocorticoids in mother's milk have been associated with offspring behavioral phenotype in several mammals, but studies have been handicapped by not simultaneously evaluating milk energy density and yield. This is problematic as milk glucocorticoids and nutrients likely have simultaneous effects on offspring phenotype. We investigated mother's milk and infant temperament and growth in a cohort of rhesus macaque (Macaca mulatta) mother-infant dyads at the California National Primate Research Center (N = 108). Glucocorticoids in mother's milk, independent of available milk energy, predicted a more Nervous, less Confident temperament in both sons and daughters. We additionally found sex differences in the windows of sensitivity and the magnitude of sensitivity to maternal-origin glucocorticoids. Lower parity mothers produced milk with higher cortisol concentrations. Lastly, higher cortisol concentrations in milk were associated with greater infant weight gain across time. Taken together, these results suggest that mothers with fewer somatic resources, even in captivity, may be "programming" through cortisol signaling, behaviorally cautious offspring that prioritize growth. Glucocorticoids ingested through milk may importantly contribute to the assimilation of available milk energy, development of temperament, and orchestrate, in part, the allocation of maternal milk energy between growth and behavioral phenotype.

  19. Cortisol in mother’s milk across lactation reflects maternal life history and predicts infant temperament

    Science.gov (United States)

    Skibiel, Amy L.; Foster, Alison B.; Del Rosso, Laura; Mendoza, Sally P.; Capitanio, John P.

    2015-01-01

    The maternal environment exerts important influences on offspring mass/growth, metabolism, reproduction, neurobiology, immune function, and behavior among birds, insects, reptiles, fish, and mammals. For mammals, mother’s milk is an important physiological pathway for nutrient transfer and glucocorticoid signaling that potentially influences offspring growth and behavioral phenotype. Glucocorticoids in mother’s milk have been associated with offspring behavioral phenotype in several mammals, but studies have been handicapped by not simultaneously evaluating milk energy density and yield. This is problematic as milk glucocorticoids and nutrients likely have simultaneous effects on offspring phenotype. We investigated mother’s milk and infant temperament and growth in a cohort of rhesus macaque (Macaca mulatta) mother–infant dyads at the California National Primate Research Center (N = 108). Glucocorticoids in mother’s milk, independent of available milk energy, predicted a more Nervous, less Confident temperament in both sons and daughters. We additionally found sex differences in the windows of sensitivity and the magnitude of sensitivity to maternal-origin glucocorticoids. Lower parity mothers produced milk with higher cortisol concentrations. Lastly, higher cortisol concentrations in milk were associated with greater infant weight gain across time. Taken together, these results suggest that mothers with fewer somatic resources, even in captivity, may be “programming” through cortisol signaling, behaviorally cautious offspring that prioritize growth. Glucocorticoids ingested through milk may importantly contribute to the assimilation of available milk energy, development of temperament, and orchestrate, in part, the allocation of maternal milk energy between growth and behavioral phenotype. PMID:25713475

  20. Life Prediction Model for Grid-Connected Li-ion Battery Energy Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Saxon, Aron R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Keyser, Matthew A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lundstrom, Blake R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cao, Ziwei [SunPower Corporation; Roc, Albert [SunPower Corporation

    2017-09-06

    Lithium-ion (Li-ion) batteries are being deployed on the electrical grid for a variety of purposes, such as to smooth fluctuations in solar renewable power generation. The lifetime of these batteries will vary depending on their thermal environment and how they are charged and discharged. To optimal utilization of a battery over its lifetime requires characterization of its performance degradation under different storage and cycling conditions. Aging tests were conducted on commercial graphite/nickel-manganese-cobalt (NMC) Li-ion cells. A general lifetime prognostic model framework is applied to model changes in capacity and resistance as the battery degrades. Across 9 aging test conditions from 0oC to 55oC, the model predicts capacity fade with 1.4% RMS error and resistance growth with 15% RMS error. The model, recast in state variable form with 8 states representing separate fade mechanisms, is used to extrapolate lifetime for example applications of the energy storage system integrated with renewable photovoltaic (PV) power generation.

  1. A Stochastic Energy Budget Model Using Physically Based Red Noise

    CERN Document Server

    Weniger, Michael; Hense, Andreas

    2011-01-01

    A method to describe unresolved processes in meteorological models by physically based stochastic processes (SP) is proposed by the example of an energy budget model (EBM). Contrary to the common approach using additive white noise, a suitable variable within the model is chosen to be represented by a SP. Spectral analysis of ice core time series shows a red noise character of the underlying fluctuations. Fitting Ornstein Uhlenbeck processes to the observed spectrum defines the parameters for the stochastic dynamic model (SDM). Numerical simulations for different sets of ice core data lead to three sets of strongly differing systems. Pathwise, statistical and spectral analysis of these models show the importance of carefully choosing suitable stochastic terms in order to get a physically meaningful SDM.

  2. Intrinsically Disordered Proteins in a Physics-Based World

    Directory of Open Access Journals (Sweden)

    Jianhan Chen

    2010-12-01

    Full Text Available Intrinsically disordered proteins (IDPs are a newly recognized class of functional proteins that rely on a lack of stable structure for function. They are highly prevalent in biology, play fundamental roles, and are extensively involved in human diseases. For signaling and regulation, IDPs often fold into stable structures upon binding to specific targets. The mechanisms of these coupled binding and folding processes are of significant importance because they underlie the organization of regulatory networks that dictate various aspects of cellular decision-making. This review first discusses the challenge in detailed experimental characterization of these heterogeneous and dynamics proteins and the unique and exciting opportunity for physics-based modeling to make crucial contributions, and then summarizes key lessons from recent de novo simulations of the structure and interactions of several regulatory IDPs.

  3. Physics-Based Simulator for NEO Exploration Analysis & Simulation

    Science.gov (United States)

    Balaram, J.; Cameron, J.; Jain, A.; Kline, H.; Lim, C.; Mazhar, H.; Myint, S.; Nayar, H.; Patton, R.; Pomerantz, M.; hide

    2011-01-01

    As part of the Space Exploration Analysis and Simulation (SEAS) task, the National Aeronautics and Space Administration (NASA) is using physics-based simulations at NASA's Jet Propulsion Laboratory (JPL) to explore potential surface and near-surface mission operations at Near Earth Objects (NEOs). The simulator is under development at JPL and can be used to provide detailed analysis of various surface and near-surface NEO robotic and human exploration concepts. In this paper we describe the SEAS simulator and provide examples of recent mission systems and operations concepts investigated using the simulation. We also present related analysis work and tools developed for both the SEAS task as well as general modeling, analysis and simulation capabilites for asteroid/small-body objects.

  4. Physics-Based Simulator for NEO Exploration Analysis & Simulation

    Science.gov (United States)

    Balaram, J.; Cameron, J.; Jain, A.; Kline, H.; Lim, C.; Mazhar, H.; Myint, S.; Nayar, H.; Patton, R.; Pomerantz, M.; Quadrelli, M.; Shakkotai, P.; Tso, K.

    2011-01-01

    As part of the Space Exploration Analysis and Simulation (SEAS) task, the National Aeronautics and Space Administration (NASA) is using physics-based simulations at NASA's Jet Propulsion Laboratory (JPL) to explore potential surface and near-surface mission operations at Near Earth Objects (NEOs). The simulator is under development at JPL and can be used to provide detailed analysis of various surface and near-surface NEO robotic and human exploration concepts. In this paper we describe the SEAS simulator and provide examples of recent mission systems and operations concepts investigated using the simulation. We also present related analysis work and tools developed for both the SEAS task as well as general modeling, analysis and simulation capabilites for asteroid/small-body objects.

  5. Engineering uses of physics-based ground motion simulations

    Science.gov (United States)

    Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

    2014-01-01

    This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

  6. Bio-Soliton Model that predicts Non-Thermal Electromagnetic Radiation Frequency Bands, that either Stabilize or Destabilize Life Conditions

    CERN Document Server

    Geesink, J H

    2016-01-01

    Solitons, as self-reinforcing solitary waves, interact with complex biological phenomena such as cellular self-organisation. Soliton models are able to describe a spectrum of electromagnetism modalities that can be applied to understand the physical principles of biological effects in living cells, as caused by electromagnetic radiation. A bio-soliton model is proposed, that enables to predict which eigen-frequencies of non-thermal electromagnetic waves are life-sustaining and which are, in contrast, detrimental for living cells. The particular effects are exerted by a range of electromagnetic wave frequencies of one-tenth of a Hertz till Peta Hertz, that show a pattern of twelve bands, if positioned on an acoustic frequency scale. The model was substantiated by a meta-analysis of 240 published papers of biological radiation experiments, in which a spectrum of non-thermal electromagnetic waves were exposed to living cells and intact organisms. These data support the concept of coherent quantized electromagnet...

  7. Integrated Condition Monitoring and Prognosis Method for Incipient Defect Detection and Remaining Life Prediction of Low Speed Slew Bearings

    Directory of Open Access Journals (Sweden)

    Wahyu Caesarendra

    2017-04-01

    Full Text Available This paper presents an application of multivariate state estimation technique (MSET, sequential probability ratio test (SPRT and kernel regression for low speed slew bearing condition monitoring and prognosis. The method is applied in two steps. Step (1 is the detection of the incipient slew bearing defect. In this step, combined MSET and SPRT is used with circular-domain kurtosis, time-domain kurtosis, wavelet decomposition (WD kurtosis, empirical mode decomposition (EMD kurtosis and the largest Lyapunov exponent (LLE feature. Step (2 is the prediction of the selected features’ trends and the estimation of the remaining useful life (RUL of the slew bearing. In this step, kernel regression is used with time-domain kurtosis, WD kurtosis and the LLE feature. The application of the method is demonstrated with laboratory slew bearing acceleration data.

  8. Electrical Resistance of SiC/SiC Ceramic Matrix Composites for Damage Detection and Life-Prediction

    Science.gov (United States)

    Smith, Craig; Morscher, Gregory; Xia, Zhenhai

    2009-01-01

    Ceramic matrix composites (CMC) are suitable for high temperature structural applications such as turbine airfoils and hypersonic thermal protection systems due to their low density high thermal conductivity. The employment of these materials in such applications is limited by the ability to accurately monitor and predict damage evolution. Current nondestructive methods such as ultrasound, x-ray, and thermal imaging are limited in their ability to quantify small scale, transverse, in-plane, matrix cracks developed over long-time creep and fatigue conditions. CMC is a multifunctional material in which the damage is coupled with the material s electrical resistance, providing the possibility of real-time information about the damage state through monitoring of resistance. Here, resistance measurement of SiC/SiC composites under mechanical load at both room temperature monotonic and high temperature creep conditions, coupled with a modal acoustic emission technique, can relate the effects of temperature, strain, matrix cracks, fiber breaks, and oxidation to the change in electrical resistance. A multiscale model can in turn be developed for life prediction of in-service composites, based on electrical resistance methods. Results of tensile mechanical testing of SiC/SiC composites at room and high temperatures will be discussed. Data relating electrical resistivity to composite constituent content, fiber architecture, temperature, matrix crack formation, and oxidation will be explained, along with progress in modeling such properties.

  9. Role of nutritional status in predicting quality of life outcomes in cancer – a systematic review of the epidemiological literature

    Science.gov (United States)

    2012-01-01

    Malnutrition is a significant factor in predicting cancer patients’ quality of life (QoL). We systematically reviewed the literature on the role of nutritional status in predicting QoL in cancer. We searched MEDLINE database using the terms “nutritional status” in combination with “quality of life” together with “cancer”. Human studies published in English, having nutritional status as one of the predictor variables, and QoL as one of the outcome measures were included. Of the 26 included studies, 6 investigated head and neck cancer, 8 gastrointestinal, 1 lung, 1 gynecologic and 10 heterogeneous cancers. 24 studies concluded that better nutritional status was associated with better QoL, 1 study showed that better nutritional status was associated with better QoL only in high-risk patients, while 1 study concluded that there was no association between nutritional status and QoL. Nutritional status is a strong predictor of QoL in cancer patients. We recommend that more providers implement the American Society of Parenteral and Enteral Nutrition (ASPEN) guidelines for oncology patients, which includes nutritional screening, nutritional assessment and intervention as appropriate. Correcting malnutrition may improve QoL in cancer patients, an important outcome of interest to cancer patients, their caregivers, and families. PMID:22531478

  10. Assessment of Predictable Productivity of Nurses Working in Kerman University of Medical Sciences' Teaching Hospitals via the Dimensions of Quality of Work Life.

    Science.gov (United States)

    Borhani, Fariba; Arbabisarjou, Azizollah; Kianian, Toktam; Saber, Saman

    2016-10-01

    Despite the existence of a large community of nurses, specific mechanisms have not been developed yet to consider their needs and the quality of their work life. Moreover, few studies have been conducted to analyze the nature of nursing, nursing places or nurses' quality of work life. In this regard, the present study aimed to assess predictable productivity of nurses working in Kerman University of Medical Sciences' teaching hospitals via the dimensions of Quality of Work Life. The present descriptive-correlational study was conducted to assess predictable productivity of nurses via the dimensions of Quality of Work Life. The study's population consisted of all nurses working in different wards of teaching hospitals associated with Kerman University of Medical Sciences. Out of the whole population, 266 nurses were selected based on the simple random sampling method. To collect data, the questionnaires of 'Quality of Nursing Work Life' and 'Productivity' were used after confirming their reliability (test-retest) and content validity. Finally, the collected data were analyzed through the SPSS software (version 16). Although the quality of work life for nurses was average and their productivity was low but the results showed that quality of life is directly related to nurses' productivity. Quality of life and its dimensions are predictive factors in the in the nurses' productivity. It can conclude that by recognizing the nurses' quality of work life situation, it can realize this group productivity and their values to the efficiency of the health system. For the quality of working life improvement and increasing nurses' productivity more efforts are needed by authorities. The findings can be applied by managers of hospitals and nursing services along with head nurses to enhance the quality of health services and nursing profession in general.

  11. Symptoms and quality of life in late stage Parkinson syndromes: a longitudinal community study of predictive factors.

    Directory of Open Access Journals (Sweden)

    Irene J Higginson

    Full Text Available BACKGROUND: Palliative care is increasingly offered earlier in the cancer trajectory but rarely in Idiopathic Parkinson's Disease(IPD, Progressive Supranuclear Palsy(PSP or Multiple System Atrophy(MSA. There is little longitudinal data of people with late stage disease to understand levels of need. We aimed to determine how symptoms and quality of life of these patients change over time; and what demographic and clinical factors predicted changes. METHODS: We recruited 82 patients into a longitudinal study, consenting patients with a diagnosis of IPD, MSA or PSP, stages 3-5 Hoehn and Yahr(H&Y. At baseline and then on up to 3 occasions over one year, we collected self-reported demographic, clinical, symptom, palliative and quality of life data, using Parkinson's specific and generic validated scales, including the Palliative care Outcome Scale (POS. We tested for predictors using multivariable analysis, adjusting for confounders. FINDINGS: Over two thirds of patients had severe disability, over one third being wheelchair-bound/bedridden. Symptoms were highly prevalent in all conditions - mean (SD of 10.6(4.0 symptoms. More than 50% of the MSA and PSP patients died over the year. Over the year, half of the patients showed either an upward (worsening, 24/60 or fluctuant (8/60 trajectory for POS and symptoms. The strongest predictors of higher levels of symptoms at the end of follow-up were initial scores on POS (AOR 1.30; 95%CI:1.05-1.60 and being male (AOR 5.18; 95% CI 1.17 to 22.92, both were more predictive than initial H&Y scores. INTERPRETATION: The findings point to profound and complex mix of non-motor and motor symptoms in patients with late stage IPD, MSA and PSP. Symptoms are not resolved and half of the patients deteriorate. Palliative problems are predictive of future symptoms, suggesting that an early palliative assessment might help screen for those in need of earlier intervention.

  12. Caenorhabditis elegans genomic response to soil bacteria predicts environment-specific genetic effects on life history traits.

    Directory of Open Access Journals (Sweden)

    Joseph D Coolon

    2009-06-01

    Full Text Available With the post-genomic era came a dramatic increase in high-throughput technologies, of which transcriptional profiling by microarrays was one of the most popular. One application of this technology is to identify genes that are differentially expressed in response to different environmental conditions. These experiments are constructed under the assumption that the differentially expressed genes are functionally important in the environment where they are induced. However, whether differential expression is predictive of functional importance has yet to be tested. Here we have addressed this expectation by employing Caenorhabditis elegans as a model for the interaction of native soil nematode taxa and soil bacteria. Using transcriptional profiling, we identified candidate genes regulated in response to different bacteria isolated in association with grassland nematodes or from grassland soils. Many of the regulated candidate genes are predicted to affect metabolism and innate immunity suggesting similar genes could influence nematode community dynamics in natural systems. Using mutations that inactivate 21 of the identified genes, we showed that most contribute to lifespan and/or fitness in a given bacterial environment. Although these bacteria may not be natural food sources for C. elegans, we show that changes in food source, as can occur in environmental disturbance, can have a large effect on gene expression, with important consequences for fitness. Moreover, we used regression analysis to demonstrate that for many genes the degree of differential gene expression between two bacterial environments predicted the magnitude of the effect of the loss of gene function on life history traits in those environments.

  13. Numerical investigation and experimental validation of physically based advanced GTN model for DP steels

    Energy Technology Data Exchange (ETDEWEB)

    Fansi, Joseph, E-mail: jfansi@doct.ulg.ac.be [University of Liège, Departement ArGEnCo, Division MS2F, Chemin des Chevreuils 1, Liège 4000 (Belgium); Arts et Métiers ParisTech, LEM3, UMR CNRS 7239, 4 rue A. Fresnel, 57078 Metz cedex 03 (France); ArcelorMittal R and D Global Maizières S.A., voie Romaine, Maizières-Lès-Metz 57238 (France); Balan, Tudor [Arts et Métiers ParisTech, LEM3, UMR CNRS 7239, 4 rue A. Fresnel, 57078 Metz cedex 03 (France); Lemoine, Xavier [Arts et Métiers ParisTech, LEM3, UMR CNRS 7239, 4 rue A. Fresnel, 57078 Metz cedex 03 (France); ArcelorMittal R and D Global Maizières S.A., voie Romaine, Maizières-Lès-Metz 57238 (France); Maire, Eric; Landron, Caroline [INSA de Lyon, MATEIS CNRS UMR5510, 7 Avenue Jean Capelle, Villeurbanne 69621 (France); Bouaziz, Olivier [ArcelorMittal R and D Global Maizières S.A., voie Romaine, Maizières-Lès-Metz 57238 (France); Ecole des Mines de Paris, Centre des Matériaux, CNRS UMR 7633, BP 87, Evry Cedex 91003 (France); Ben Bettaieb, Mohamed [Ensicaen, 6 Boulevard du Maréchal Juin, 14050 CAEN Cedex 4 (France); Marie Habraken, Anne [University of Liège, Departement ArGEnCo, Division MS2F, Chemin des Chevreuils 1, Liège 4000 (Belgium)

    2013-05-01

    This numerical investigation of an advanced Gurson–Tvergaard–Needleman (GTN) model is an extension of the original work of Ben Bettaiebet al. (2011 [18]). The model has been implemented as a user-defined material model subroutine (VUMAT) in the Abaqus/explicit FE code. The current damage model extends the previous version by integrating the three damage mechanisms: nucleation, growth and coalescence of voids. Physically based void nucleation and growth laws are considered, including an effect of the kinematic hardening. These new contributions are based and validated on experimental results provided by high-resolution X-ray absorption tomography measurements. The current damage model is applied to predict the damage evolution and the stress state in a tensile notched specimen experiment.

  14. Physically-based approach to analyze rainfall-triggered landslide using hydraulic gradient as slide direction

    Institute of Scientific and Technical Information of China (English)

    Qi-hua RAN; Dan-yang SU; Qun QIAN; Xu-dong FU; Guang-qian WANG; Zhi-guo HE

    2012-01-01

    An infinite slope stability numerical model driven by the comprehensive physically-based integrated hydrology model (InHM) is presented.In this approach,the failure plane is assumed to be parallel to the hydraulic gradient instead of the slope surface.The method helps with irregularities in complex terrain since depressions and flat areas are allowed in the model.The present model has been tested for two synthetic single slopes and a small catchment in the Mettman Ridge study area in Oregon,United States,to estimate the shallow landslide susceptibility.The results show that the present approach can reduce the simulation error of hydrological factors caused by the rolling topography and depressions,and is capable of estimating spatial-temporal variations for landslide susceptibilities at simple slopes as well as at catchment scale,providing a valuable tool for the prediction of shallow landslides.

  15. Physics Based Modeling and Rendering of Vegetation in the Thermal Infrared

    Science.gov (United States)

    Smith, J. A.; Ballard, J. R., Jr.

    1999-01-01

    We outline a procedure for rendering physically-based thermal infrared images of simple vegetation scenes. Our approach incorporates the biophysical processes that affect the temperature distribution of the elements within a scene. Computer graphics plays a key role in two respects. First, in computing the distribution of scene shaded and sunlit facets and, second, in the final image rendering once the temperatures of all the elements in the scene have been computed. We illustrate our approach for a simple corn scene where the three-dimensional geometry is constructed based on measured morphological attributes of the row crop. Statistical methods are used to construct a representation of the scene in agreement with the measured characteristics. Our results are quite good. The rendered images exhibit realistic behavior in directional properties as a function of view and sun angle. The root-mean-square error in measured versus predicted brightness temperatures for the scene was 2.1 deg C.

  16. Physics Based Model for Cryogenic Chilldown and Loading. Part I: Algorithm

    Science.gov (United States)

    Luchinsky, Dmitry G.; Smelyanskiy, Vadim N.; Brown, Barbara

    2014-01-01

    We report the progress in the development of the physics based model for cryogenic chilldown and loading. The chilldown and loading is model as fully separated non-equilibrium two-phase flow of cryogenic fluid thermally coupled to the pipe walls. The solution follow closely nearly-implicit and semi-implicit algorithms developed for autonomous control of thermal-hydraulic systems developed by Idaho National Laboratory. A special attention is paid to the treatment of instabilities. The model is applied to the analysis of chilldown in rapid loading system developed at NASA-Kennedy Space Center. The nontrivial characteristic feature of the analyzed chilldown regime is its active control by dump valves. The numerical predictions are in reasonable agreement with the experimental time traces. The obtained results pave the way to the development of autonomous loading operation on the ground and space.

  17. Physically-based Assessment of Tropical Cyclone Damage and Economic Losses

    Science.gov (United States)

    Lin, N.

    2012-12-01

    Estimating damage and economic losses caused by tropical cyclones (TC) is a topic of considerable research interest in many scientific fields, including meteorology, structural and coastal engineering, and actuarial sciences. One approach is based on the empirical relationship between TC characteristics and loss data. Another is to model the physical mechanism of TC-induced damage. In this talk we discuss about the physically-based approach to predict TC damage and losses due to extreme wind and storm surge. We first present an integrated vulnerability model, which, for the first time, explicitly models the essential mechanisms causing wind damage to residential areas during storm passage, including windborne-debris impact and the pressure-debris interaction that may lead, in a chain reaction, to structural failures (Lin and Vanmarcke 2010; Lin et al. 2010a). This model can be used to predict the economic losses in a residential neighborhood (with hundreds of buildings) during a specific TC (Yau et al. 2011) or applied jointly with a TC risk model (e.g., Emanuel et al 2008) to estimate the expected losses over long time periods. Then we present a TC storm surge risk model that has been applied to New York City (Lin et al. 2010b; Lin et al. 2012; Aerts et al. 2012), Miami-Dade County, Florida (Klima et al. 2011), Galveston, Texas (Lickley, 2012), and other coastal areas around the world (e.g., Tampa, Florida; Persian Gulf; Darwin, Australia; Shanghai, China). These physically-based models are applicable to various coastal areas and have the capability to account for the change of the climate and coastal exposure over time. We also point out that, although made computationally efficient for risk assessment, these models are not suitable for regional or global analysis, which has been a focus of the empirically-based economic analysis (e.g., Hsiang and Narita 2012). A future research direction is to simplify the physically-based models, possibly through

  18. Cyclic softening as a parameter for prediction of remnant creep rupture life of a Indian reduced activation ferritic–martensitic (IN-RAFM) steel subjected to fatigue exposures

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Aritra, E-mail: aritra@igcar.gov.in [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Vijayanand, V.D.; Shankar, Vani; Parameswaran, P.; Sandhya, R.; Laha, K.; Mathew, M.D.; Jayakumar, T. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Rajendrakumar, E. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India)

    2014-12-15

    Sequential fatigue-creep tests were conducted on Indian reduced activation ferritic–martensitic steel at 823 K leading to sharp decrease in residual creep life with increase in prior fatigue exposures. Extensive recovery of martensitic-lath structure taking place during fatigue deformation, manifested as cyclic softening in the cyclic stress response, shortens the residual creep life. Based on the experimental results, cyclic softening occurring during fatigue stage can be correlated with residual creep life, evolving in an empirical model which predicts residual creep life as a function of cyclic softening. Predicted creep lives for specimens pre-cycled at various strain amplitudes are explained on the basis of mechanism of cyclic softening.

  19. Physically based modelling of sediment generation and transport under a large rainfall simulator

    Science.gov (United States)

    Adams, Russell; Elliott, Sandy

    2006-07-01

    A series of large rainfall simulator experiments was conducted in 2002 and 2003 on a small plot located in an experimental catchment in the North Island of New Zealand. These experiments measured both runoff and sediment transport under carefully controlled conditions. A physically based hydrological modelling system (SHETRAN) was then applied to reproduce the observed hydrographs and sedigraphs. SHETRAN uses physically based equations to represent flow and sediment transport, and two erodibility coefficients to model detachment of soil particles by raindrop erosion and overland flow erosion. The rate of raindrop erosion also depended on the amount of bare ground under the simulator; this was estimated before each experiment. These erodibility coefficients were calibrated systematically for summer and winter experiments separately, and lower values were obtained for the summer experiments. Earlier studies using small rainfall simulators in the vicinity of the plot also found the soil to be less erodible in summer and autumn. Limited validation of model parameters was carried out using results from a series of autumn experiments. The modelled suspended sediment load was also sensitive to parameters controlling the generation of runoff from the rainfall simulator plot; therefore, we found that accurate runoff predictions were important for the sediment predictions, especially from the experiments where the pasture cover was good and overland flow erosion was the dominant mechanism. The rainfall simulator experiments showed that the mass of suspended sediment increased post-grazing, and according to the model this was due to raindrop detachment. The results indicated that grazing cattle or sheep on steeply sloping hill-country paddocks should be carefully managed, especially in winter, to limit the transport of suspended sediment into watercourses.

  20. How to Make Our Models More Physically-based

    Science.gov (United States)

    Savenije, H. H. G.

    2016-12-01

    Models that are generally called "physically-based" unfortunately only have a partial view of the physical processes at play in hydrology. Although the coupled partial differential equations in these models reflect the water balance equations and the flow descriptors at laboratory scale, they miss essential characteristics of what determines the functioning of catchments. The most important active agent in catchments is the ecosystem (and sometimes people). What these agents do is manipulate the substrate in a way that it supports the essential functions of survival and productivity: infiltration of water, retention of moisture, mobilization and retention of nutrients, and drainage. Ecosystems do this in the most efficient way, in agreement with the landscape, and in response to climatic drivers. In brief, our hydrological system is alive and has a strong capacity to adjust to prevailing and changing circumstances. Although most physically based models take Newtonian theory at heart, as best they can, what they generally miss is Darwinian thinking on how an ecosystem evolves and adjusts its environment to maintain crucial hydrological functions. If this active agent is not reflected in our models, then they miss essential physics. Through a Darwinian approach, we can determine the root zone storage capacity of ecosystems, as a crucial component of hydrological models, determining the partitioning of fluxes and the conservation of moisture to bridge periods of drought. Another crucial element of physical systems is the evolution of drainage patterns, both on and below the surface. On the surface, such patterns facilitate infiltration or surface drainage with minimal erosion; in the unsaturated zone, patterns facilitate efficient replenishment of moisture deficits and preferential drainage when there is excess moisture; in the groundwater, patterns facilitate the efficient and gradual drainage of groundwater, resulting in linear reservoir recession. Models that do

  1. Physically-Based Shallow Landslide Susceptibility Mapping, NW of Portugal

    Science.gov (United States)

    Teixeira, Manuel; Bateira, Carlos; Soares, Laura

    2013-04-01

    Two physically-based models - Shallow Landslide Stability Analysis (SHALSTAB) and Safety Factor (SF) - are applied in Serra da Peneda (northwest of Portugal) to evaluate shallow landslide susceptibility in Tibo drainage basin. This small basin is located in an area of granitic and metasedimentary substrate, covered by different types of surficial formations (weathering mantles and slope deposits). The application of the selected models requires the determination of a set of mechanical and hydrological parameters, and the use of high resolution topographic information to create an accurate DTM. To fulfill this goal we have applied the Shallow Landslide Stability Analysis (SHALSTAB) and the SF (Safety Factor) models. The shallow landslide area was inventoried on the field. The cohesion was assessed by back analysis and the other mechanical and hydrological soil parameters were assessed on the field survey. Several susceptibility scenarios were tested with SHALSTAB model. The best SHALSTAB scenario used to assess the susceptibility is achieved using the following parameters: cohesion (c) = 2000 N/m2, soil thickness (z) = 1,2 m, internal friction (?)=32o and soil weight (?s)=14,7 KN/m3. Shallow landslide susceptibility mapping using the SF model, was based on the cartography of the factors registered on the field survey and used the following parameters: cohesion (c) = 2000 - 6000 N/m2, soil thickness (z) =1,2 m, internal friction (?)=30 - 40o; soil volumic weight (?m) = 13,7 - 15,7 KN/m3 and Hydraulic conductivity = 0 - 3,9-03 kfs. SHALSTAB scenarios were validated by overlaying the shallow landslide area (scar concentration) and selected the better susceptibility modeling. The parameters used on the SF model applied spatially variable values registered in the field survey (using the superficial formation cartography). To validate the SF model we used the AUC (Area Under the Curve) method. The two models were compared by the scar concentration and landslide potential

  2. Quantification of Uncertainties in Turbulence Modeling: A Comparison of Physics-Based and Random Matrix Theoretic Approaches

    CERN Document Server

    Wang, Jian-Xun; Xiao, Heng

    2016-01-01

    Numerical models based on Reynolds-Averaged Navier-Stokes (RANS) equations are widely used in engineering turbulence modeling. However, the RANS predictions have large model-form uncertainties for many complex flows. Quantification of these large uncertainties originating from the modeled Reynolds stresses has attracted attention in turbulence modeling community. Recently, a physics-based Bayesian framework for quantifying model-form uncertainties has been proposed with successful applications to several flows. Nonetheless, how to specify proper priors without introducing unwarranted, artificial information remains challenging to the current form of the physics-based approach. Another recently proposed method based on random matrix theory provides the prior distributions with the maximum entropy, which is an alternative for model-form uncertainty quantification in RANS simulations. In this work, we utilize the random matrix theoretic approach to assess and possibly improve the specification of priors used in ...

  3. Physics-Based Haptic Simulation of Bone Machining.

    Science.gov (United States)

    Arbabtafti, M; Moghaddam, M; Nahvi, A; Mahvash, M; Richardson, B; Shirinzadeh, B

    2011-01-01

    We present a physics-based training simulator for bone machining. Based on experimental studies, the energy required to remove a unit volume of bone is a constant for every particular bone material. We use this physical principle to obtain the forces required to remove bone material with a milling tool rotating at high speed. The rotating blades of the tool are modeled as a set of small cutting elements. The force of interaction between a cutting element and bone is calculated from the energy required to remove a bone chip with an estimated thickness and known material stiffness. The total force acting on the cutter at a particular instant is obtained by integrating the differential forces over all cutting elements engaged. A voxel representation is used to represent the virtual bone and removed chips for calculating forces of machining. We use voxels that carry bone material properties to represent the volumetric haptic body and to apply underlying physical changes during machining. Experimental results of machining samples of a real bone confirm the force model. A real-time haptic implementation of the method in a dental training simulator is described.

  4. Physically based analysis of deformations in 3D images

    Science.gov (United States)

    Nastar, Chahab; Ayache, Nicholas

    1993-06-01

    We present a physically based deformable model which can be used to track and to analyze the non-rigid motion of dynamic structures in time sequences of 2-D or 3-D medical images. The model considers an object undergoing an elastic deformation as a set of masses linked by springs, where the natural lengths of the springs is set equal to zero, and is replaced by a set of constant equilibrium forces, which characterize the shape of the elastic structure in the absence of external forces. This model has the extremely nice property of yielding dynamic equations which are linear and decoupled for each coordinate, whatever the amplitude of the deformation. It provides a reduced algorithmic complexity, and a sound framework for modal analysis, which allows a compact representation of a general deformation by a reduced number of parameters. The power of the approach to segment, track, and analyze 2-D and 3-D images is demonstrated by a set of experimental results on various complex medical images.

  5. Physically-based, Hydrologic Simulations Driven by Three Precipitation Products

    Science.gov (United States)

    Chintalapudi, S.; Sharif, H. O.; Yeggina, S.; El Hassan, A.

    2011-12-01

    This study evaluates the model-simulated stream discharge over the Guadalupe River basin in central Texas driven by three precipitation products: the Guadalupe-Blanco River Authority (GBRA) rain gauge network, the Next Generation Weather Radar (NEXRAD) Stage ΙΙΙ precipitation product, and the Tropical Rainfall Measurement Mission (TRMM) 3B42 product. Focus will be on results from the Upper Guadalupe River sub-basin. This sub-basin is more prone to flooding due to its geological properties (thin soils, exposed bedrock, and sparse vegetation) and the impact of Balcones Escarpment on the moisture coming from the Gulf of Mexico. The physically based, distributed-parameter Gridded Surface Subsurface Hydrologic Analysis (GSSHA) hydrologic model was used to simulate the June-2002 flooding event. Simulations driven by NEXRAD Stage ΙΙΙ 15 - min precipitation yielded better results with low RMSE (88.3%), high NSE (0.6), high R2 (0.73), low RSR (0.63) and low PBIAS (-17.3%) compared to simulations driven by the other products.

  6. Physics-based Entry, Descent and Landing Risk Model

    Science.gov (United States)

    Gee, Ken; Huynh, Loc C.; Manning, Ted

    2014-01-01

    A physics-based risk model was developed to assess the risk associated with thermal protection system failures during the entry, descent and landing phase of a manned spacecraft mission. In the model, entry trajectories were computed using a three-degree-of-freedom trajectory tool, the aerothermodynamic heating environment was computed using an engineering-level computational tool and the thermal response of the TPS material was modeled using a one-dimensional thermal response tool. The model was capable of modeling the effect of micrometeoroid and orbital debris impact damage on the TPS thermal response. A Monte Carlo analysis was used to determine the effects of uncertainties in the vehicle state at Entry Interface, aerothermodynamic heating and material properties on the performance of the TPS design. The failure criterion was set as a temperature limit at the bondline between the TPS and the underlying structure. Both direct computation and response surface approaches were used to compute the risk. The model was applied to a generic manned space capsule design. The effect of material property uncertainty and MMOD damage on risk of failure were analyzed. A comparison of the direct computation and response surface approach was undertaken.

  7. Prediction

    CERN Document Server

    Sornette, Didier

    2010-01-01

    This chapter first presents a rather personal view of some different aspects of predictability, going in crescendo from simple linear systems to high-dimensional nonlinear systems with stochastic forcing, which exhibit emergent properties such as phase transitions and regime shifts. Then, a detailed correspondence between the phenomenology of earthquakes, financial crashes and epileptic seizures is offered. The presented statistical evidence provides the substance of a general phase diagram for understanding the many facets of the spatio-temporal organization of these systems. A key insight is to organize the evidence and mechanisms in terms of two summarizing measures: (i) amplitude of disorder or heterogeneity in the system and (ii) level of coupling or interaction strength among the system's components. On the basis of the recently identified remarkable correspondence between earthquakes and seizures, we present detailed information on a class of stochastic point processes that has been found to be particu...

  8. Early-Life Telomere Dynamics Differ between the Sexes and Predict Growth in the Barn Swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Marco Parolini

    Full Text Available Telomeres are conserved DNA-protein structures at the termini of eukaryotic chromosomes which contribute to maintenance of genome integrity, and their shortening leads to cell senescence, with negative consequences for organismal functions. Because telomere erosion is influenced by extrinsic and endogenous factors, telomere dynamics may provide a mechanistic basis for evolutionary and physiological trade-offs. Yet, knowledge of fundamental aspects of telomere biology under natural selection regimes, including sex- and context-dependent variation in early-life, and the covariation between telomere dynamics and growth, is scant. In this study of barn swallows (Hirundo rustica we investigated the sex-dependent telomere erosion during nestling period, and the covariation between relative telomere length and body and plumage growth. Finally, we tested whether any covariation between growth traits and relative telomere length depends on the social environment, as influenced by sibling sex ratio. Relative telomere length declined on average over the period of nestling maximal growth rate (between 7 and 16 days of age and differently covaried with initial relative telomere length in either sex. The frequency distribution of changes in relative telomere length was bimodal, with most nestlings decreasing and some increasing relative telomere length, but none of the offspring traits predicted the a posteriori identified group to which individual nestlings belonged. Tail and wing length increased with relative telomere length, but more steeply in males than females, and this relationship held both at the within- and among-broods levels. Moreover, the increase in plumage phenotypic values was steeper when the sex ratio of an individual's siblings was female-biased. Our study provides evidence for telomere shortening during early life according to subtly different dynamics in either sex. Furthermore, it shows that the positive covariation between growth and

  9. FATIGUE LIFE PREDICTION OF CRANKSHAFT MADE OF MATERIAL 48MnV BASED ON FATIGUE TESTS,DYNAMIC SIMULATION AND FEA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guoqing; PU Gengqiang; WANG Chengtao

    2006-01-01

    S-N curve and fatigue parameters of 48MnV are obtained using small sample tests and staircase or up and down method, which paves the way for predicting fatigue life of crankshaft made of 48MnV. The fatigue life of the crankshaft of a six-cylinder engine is calculated using different damage models such as S-N method, normal strain approach, Smoth-Watson-Topper (SWT)-Bannantine approach, shear strain approach, and Fatemi-Socie method based on dynamic simulation and finite element analysis (FEA) of crankshaft. The results indicate that the traditional calculation is conservative and the residual fatigue life of crankshaft is sufficient to maintain next life cycle if the crankshaft is remanufactured after its end of life.

  10. Self-compassion directly and indirectly predicts dietary adherence and quality of life among adults with celiac disease.

    Science.gov (United States)

    Dowd, A Justine; Jung, Mary E

    2017-06-01

    Strict adherence to a gluten-free diet (GFD) is the only treatment for preventing both short- and long-term consequences of celiac disease. Given that following a strict GFD can be difficult, evidence-based strategies are needed to improve the psychological experience of living with celiac disease and following the GFD. Self-compassion appears to be an important component of effectively self-regulating one's behavior to cope with a chronic disease. The main goal of this study was to examine the relationships between self-compassion and management of celiac disease as assessed by (a) adherence to a strict GFD and (b) celiac-specific quality of life (CQoL). The secondary goal of this study was to explore self-regulatory efficacy (i.e., confidence in one's ability to self-manage behavior to follow a strict GFD) and concurrent self-regulatory efficacy (i.e., one's confidence to self-manage other valued life goals while following a strict GFD) as mediators of the relationship between self-compassion and the primary outcomes (adherence and CQoL). In this prospective study, 200 North American adults diagnosed with celiac disease completed online questionnaires at two time points (baseline and 1 month later). Self-compassion at baseline directly predicted stricter adherence (at Time 2; b = -0.63, p = 0.006) and enhanced CQoL (at Time 2; b = -0.50, p = 0.001). Further, self-compassion (at Time 1) also indirectly predicted stricter Time 2 adherence through self-regulatory efficacy (at Time 1; b = -0.26, 95% CI [-0.58, -0.04], R(2) = 0.29) and enhanced Time 2 CQoL through concurrent self-regulatory efficacy (at Time 1; b = -0.07, 95% CI [-0.14, -0.03], R(2) = 0.33). This was the first study to assess the effects of self-compassion in relation to the psychological experience of coping with celiac disease and following a GFD. The findings indicate that self-compassion, self-regulatory efficacy and concurrent self-regulatory efficacy are important cognitions in

  11. Use of the Charlson Combined Comorbidity Index To Predict Postradiotherapy Quality of Life for Prostate Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Wahlgren, Thomas, E-mail: thomas.wahlgren@telia.com [Department of Oncology-Pathology, Karolinska University Hospital and Institutet, Stockholm (Sweden); Levitt, Seymour [Department of Oncology-Pathology, Karolinska University Hospital and Institutet, Stockholm (Sweden); Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Kowalski, Jan [Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm (Sweden); Nilsson, Sten; Brandberg, Yvonne [Department of Oncology-Pathology, Karolinska University Hospital and Institutet, Stockholm (Sweden)

    2011-11-15

    Purpose: To determine the impact of pretreatment comorbidity on late health-related quality of life (HRQoL) scores after patients have undergone combined radiotherapy for prostate cancer, including high-dose rate brachytherapy boost and hormonal deprivation therapy. Methods and Materials: Results from the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire survey of 158 patients 5 years or more after completion of therapy were used from consecutively accrued subjects treated with curative radiotherapy at our institution, with no signs of disease at the time of questionnaire completion. HRQoL scores were compared with the Charlson combined comorbidity index (CCI), using analysis of covariance and multivariate regression models together with pretreatment factors including tumor stage, tumor grade, pretreatment prostate-specific antigen level, neoadjuvant hormonal treatment, diabetes status, cardiovascular status, and age and Charlson score as separate variables or the composite CCI. Results: An inverse correlation between the two HRQoL domains, long-term global health (QL) and physical function (PF) scores, and the CCI score was observed, indicating an impact of comorbidity in these function areas. Selected pretreatment factors poorly explained the variation in functional HRQoL in the multivariate models; however, a statistically significant impact was found for the CCI (with QL and PF scores) and the presence of diabetes (with QL and emotional function). Cognitive function and social function were not statistically significantly predicted by any of the pretreatment factors. Conclusions: The CCI proved to be valid in this context, but it seems useful mainly in predicting long-term QL and PF scores. Of the other variables investigated, diabetes had more impact than cardiovascular morbidity on HRQoL outcomes in prostate cancer.

  12. Quality of life predicts overall survival in women with platinum-resistant ovarian cancer: an AURELIA substudy.

    Science.gov (United States)

    Roncolato, F T; Gibbs, E; Lee, C K; Asher, R; Davies, L C; Gebski, V J; Friedlander, M; Hilpert, F; Wenzel, L; Stockler, M R; King, M; Pujade-Lauraine, E

    2017-08-01

    Women with platinum-resistant ovarian cancer are a heterogeneous group whose median overall survival is 12 months. We hypothesized that their quality of life (QoL) scores would be prognostic. Data from AURELIA (n = 326), a randomized trial of chemotherapy with or without bevacizumab, were used to identify baseline QoL domains [EORTC (European Organisation for Research and Treatment of Cancer) QLQ-C30 and OV28] that were significantly associated with overall survival in multivariable Cox regression analyses. Patients were classified as having good, medium, or poor risk. Cutpoints were validated in an independent dataset, CARTAXHY (n = 136). Multivariable analyses of significant QoL domains on survival were adjusted for clinicopathological prognostic factors. The additional QoL information was assessed using C statistic. In AURELIA, all domains, except cognitive function, predicted overall survival in univariable analyses. Physical function (P 93) risk categories for physical function, median overall survival was 11.0, 14.7, and 19.3 months, respectively (P 44), medium- (13-44), and low- (AURELIA (P < 0.001) and 10.5, 19.6, and 24.1 months in CARTAXHY (P = 0.02). Physical function (P = 0.02) and abdominal/gastrointestinal symptoms (P = 0.03) remained independent prognostic factors after adjustment for clinicopathological factors. The C statistic of the full model was 0.71. For QoL factors alone, patient factors alone and disease factors alone, the C statistics were 0.61, 0.61, and 0.67 respectively. Physical function and abdominal/gastrointestinal symptom scores improved predictions of overall survival over clinicopathological factors alone in platinum-resistant ovarian cancer. This additional prognostic information could improve trial stratification, patient-doctor communication about prognosis, and clinical decision-making. NCT00976911.

  13. Prediction of Cutting Tool Life Based on Support Vector Regression%基于支持向量回归机的刀具寿命预测

    Institute of Scientific and Technical Information of China (English)

    侍红岩; 吴晓强; 张春友

    2015-01-01

    刀具寿命是制定刀具需求计划、衡量刀具性能和核算成本等的重要依据。针对现有神经网络方法在预测刀具寿命方面存在的不足,提出了一种新的基于支持向量回归机的刀具寿命预测方法。在分析了影响刀具寿命预测主要因素的基础上,建立了基于支持向量回归机的刀具寿命预测模型。应用实例的仿真结果表明,所建立的预测模型具有较强的推广能力和较高的预测精度。%Cutting tool life is an important foundation for setting down cutting tool demand plan,weighing cutting tool capability and accounting cost.Aiming at the deficiencies of existing methods of neural network in prediction of cutting tool life,a new prediction method for cutting tool life was proposed based on support vector regression.Analyzing the major fac-tors which affecting prediction of cutting tool life,based on which the prediction model of cutting tool life based on support vector regression was proposed.The simulation results of application instance show that the prediction model has strong generalization ability and high prediction precision.

  14. Accelerated test methods for life prediction of hermetic motor insulation systems exposed to alternative refrigerant/lubricant mixtures

    Science.gov (United States)

    Ellis, P. F., II; Ferguson, A. F.

    1995-04-01

    In 1992, the Air-Conditioning and Refrigeration Technology Institute, Inc. (ARTI) contracted Radian Corporation to ascertain whether an improved accelerated test method or procedure could be developed that would allow prediction of the life of motor insulation materials used in hermetic motors for air-conditioning and refrigeration equipment operated with alternative refrigerant/lubricant mixtures. Phase 1 of the project, Conceptual Design of an accelerated test method and apparatus, was successfully completed in June 1993. The culmination of that effort was the concept of the Simulated Stator Unit (SSU) test. The objective of the Phase 2 limited proof-of-concept demonstration was to: answer specific engineering/design questions; design and construct an analog control sequencer and supporting apparatus; and conduct limited tests to determine the viability of the SSU test concept. This report reviews the SSU test concept, and describes the results through the conclusion of the proof-of-concept prototype tests in March 1995. The technical design issues inherent in transforming any conceptual design to working equipment have been resolved, and two test systems and controllers have been constructed. Pilot tests and three prototype tests have been completed, concluding the current phase of work. One prototype unit was tested without thermal stress loads. Twice daily insulation property measurements (IPM's) on this unit demonstrated that the insulation property measurements themselves did not degrade the SSU.

  15. Fatigue Life Prediction of Fiber-Reinforced Ceramic-Matrix Composites with Different Fiber Preforms at Room and Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Longbiao Li

    2016-03-01

    Full Text Available In this paper, the fatigue life of fiber-reinforced ceramic-matrix composites (CMCs with different fiber preforms, i.e., unidirectional, cross-ply, 2D (two dimensional, 2.5D and 3D CMCs at room and elevated temperatures in air and oxidative environments, has been predicted using the micromechanics approach. An effective coefficient of the fiber volume fraction along the loading direction (ECFL was introduced to describe the fiber architecture of preforms. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. Under cyclic fatigue loading, the fiber broken fraction was determined by combining the interface wear model and fiber statistical failure model at room temperature, and interface/fiber oxidation model, interface wear model and fiber statistical failure model at elevated temperatures, based on the assumption that the fiber strength is subjected to two-parameter Weibull distribution and the load carried by broken and intact fibers satisfies the Global Load Sharing (GLS criterion. When the broken fiber fraction approaches the critical value, the composites fatigue fracture.

  16. Fatigue life prediction in a unidirectional glass-epoxy composite material subjected to off-axis cyclic loads

    Directory of Open Access Journals (Sweden)

    Revuelta, D.

    2005-03-01

    Full Text Available Most of today s fatigue analysis and design methods for composite laminates were developed primarily on the basis of experience with homogeneous metals. Such methods are subject to serious drawbacks, however, because the failure the modes of failure observed in metals. A theoretical model for predicting the fatigue life of continuous glass-fibre/epoxy composite materials under general loading conditions has been developed on the basis of fundamental fatigue failure modes and local failure criteria.

    La mayoría de los actuales métodos de cálculo y diseño a fatiga de estructuras de materiales compuestos se han desarrollado principalmente a partir de la experiencia previa en materiales metálicos homogéneos. Sin embargo, estos métodos presentan serios inconvenientes debido a que la heterogeneidad y micro estructura orientada características de los materiales compuestos laminados provocan modos de fallo diferentes a los de los metales. Basándose en los modos fundamentales de rotura por fatiga y en criterios de rotura local, se desarrolla un modelo teórico de vida a fatiga para materiales compuestos de matriz epoxi reforzados con fibra de vidrio bajo condiciones generales de carga

  17. FATIGUE LIFE PREDICTION BASED ON MACROSCOPIC PLASTIC ZONE ON FRACTURE SURFACE OF AISI-SAE 1018 STEEL

    Directory of Open Access Journals (Sweden)

    G.M. Domínguez Almaraz

    2010-06-01

    Full Text Available This paper deals with rotating bending fatigue tests at high speed (150 Hz carried out on AISI-SAE 1018 steel with a high content of impurities (non metallic inclusions, for which the high experimental stress inside the specimen is close to the elastic limit of the material. Simulations of rotating loading are obtained by Visual NASTRAN software in order to determine the numerical stresse and strain distributions inside a hypothetical homogeneous specimen; later, this information is used for the experimental set up. A general description of experimental test machine and experimental conditions are developed and then, the experimental results are presented and discussed according the observed failure origin related to the non metallic inclusions and the associated high stress zones. Finally, a simple model is proposed to predict the fatigue life for this non homogeneous steel under high speed rotating bending fatigue tests close to the elastic limit, based on the rate between the visual macro-plastic deformation zone at fracture surface and the total fracture surface, together with the crack initiation inclusion (or inclusions located at this zone.

  18. Uniaxial and Multiaxial Fatigue Life Prediction of the Trabecular Bone Based on Physiological Loading: A Comparative Study.

    Science.gov (United States)

    Fatihhi, S J; Harun, M N; Abdul Kadir, Mohammed Rafiq; Abdullah, Jaafar; Kamarul, T; Öchsner, Andreas; Syahrom, Ardiyansyah

    2015-10-01

    Fatigue assessment of the trabecular bone has been developed to give a better understanding of bone properties. While most fatigue studies are relying on uniaxial compressive load as the method of assessment, in various cases details are missing, or the uniaxial results are not very realistic. In this paper, the effect of three different load histories from physiological loading applied on the trabecular bone were studied in order to predict the first failure surface and the fatigue lifetime. The fatigue behaviour of the trabecular bone under uniaxial load was compared to that of multiaxial load using a finite element simulation. The plastic strain was found localized at the trabecular structure under multiaxial load. On average, applying multiaxial loads reduced more than five times the fatigue life of the trabecular bone. The results provide evidence that multiaxial loading is dominated in the low cycle fatigue in contrast to the uniaxial one. Both bone volume fraction and structural model index were best predictors of failure (p < 0.05) in fatigue for both types of loading, whilst uniaxial loading has indicated better values in most cases.

  19. Advancing reservoir operation description in physically based hydrological models

    Science.gov (United States)

    Anghileri, Daniela; Giudici, Federico; Castelletti, Andrea; Burlando, Paolo

    2016-04-01

    Last decades have seen significant advances in our capacity of characterizing and reproducing hydrological processes within physically based models. Yet, when the human component is considered (e.g. reservoirs, water distribution systems), the associated decisions are generally modeled with very simplistic rules, which might underperform in reproducing the actual operators' behaviour on a daily or sub-daily basis. For example, reservoir operations are usually described by a target-level rule curve, which represents the level that the reservoir should track during normal operating conditions. The associated release decision is determined by the current state of the reservoir relative to the rule curve. This modeling approach can reasonably reproduce the seasonal water volume shift due to reservoir operation. Still, it cannot capture more complex decision making processes in response, e.g., to the fluctuations of energy prices and demands, the temporal unavailability of power plants or varying amount of snow accumulated in the basin. In this work, we link a physically explicit hydrological model with detailed hydropower behavioural models describing the decision making process by the dam operator. In particular, we consider two categories of behavioural models: explicit or rule-based behavioural models, where reservoir operating rules are empirically inferred from observational data, and implicit or optimization based behavioural models, where, following a normative economic approach, the decision maker is represented as a rational agent maximising a utility function. We compare these two alternate modelling approaches on the real-world water system of Lake Como catchment in the Italian Alps. The water system is characterized by the presence of 18 artificial hydropower reservoirs generating almost 13% of the Italian hydropower production. Results show to which extent the hydrological regime in the catchment is affected by different behavioural models and reservoir

  20. HIRESSS: a physically based slope stability simulator for HPC applications

    Directory of Open Access Journals (Sweden)

    G. Rossi

    2013-01-01

    Full Text Available HIRESSS (HIgh REsolution Slope Stability Simulator is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provides the pressure head as perturbation to the geotechnical stability model that computes the factor of safety (FS in probabilistic terms. The hydrological model is based on an analytical solution of an approximated form of the Richards equation under the wet condition hypothesis and it is introduced as a modeled form of hydraulic diffusivity to improve the hydrological response. The geotechnical stability model is based on an infinite slope model that takes into account the unsaturated soil condition. During the slope stability analysis the proposed model takes into account the increase in strength and cohesion due to matric suction in unsaturated soil, where the pressure head is negative. Moreover, the soil mass variation on partially saturated soil caused by water infiltration is modeled.

    The model is then inserted into a Monte Carlo simulation, to manage the typical uncertainty in the values of the input geotechnical and hydrological parameters, which is a common weak point of deterministic models. The Monte Carlo simulation manages a probability distribution of input parameters providing results in terms of slope failure probability. The developed software uses the computational power offered by multicore and multiprocessor hardware, from modern workstations to supercomputing facilities (HPC, to achieve the simulation in reasonable runtimes, compatible with civil protection real time monitoring.

    A first test of HIRESSS in three different areas is presented to evaluate the reliability of the results and the runtime performance on