5,954 research outputs found

    Surface flaw reliability analysis of ceramic components with the SCARE finite element postprocessor program

    Get PDF
    The SCARE (Structural Ceramics Analysis and Reliability Evaluation) computer program on statistical fast fracture reliability analysis with quadratic elements for volume distributed imperfections is enhanced to include the use of linear finite elements and the capability of designing against concurrent surface flaw induced ceramic component failure. The SCARE code is presently coupled as a postprocessor to the MSC/NASTRAN general purpose, finite element analysis program. The improved version now includes the Weibull and Batdorf statistical failure theories for both surface and volume flaw based reliability analysis. The program uses the two-parameter Weibull fracture strength cumulative failure probability distribution model with the principle of independent action for poly-axial stress states, and Batdorf's shear-sensitive as well as shear-insensitive statistical theories. The shear-sensitive surface crack configurations include the Griffith crack and Griffith notch geometries, using the total critical coplanar strain energy release rate criterion to predict mixed-mode fracture. Weibull material parameters based on both surface and volume flaw induced fracture can also be calculated from modulus of rupture bar tests, using the least squares method with known specimen geometry and grouped fracture data. The statistical fast fracture theories for surface flaw induced failure, along with selected input and output formats and options, are summarized. An example problem to demonstrate various features of the program is included

    FOOD EXPENDITURES BY U.S. HOUSEHOLDS: LOOKING AHEAD TO 2020

    Get PDF
    By 2020, the effects of demographic changes and income growth will increase per capita spending on food 7.1 percent. Income growth alone, which will effect spending increases of almost 10 percent on away-from-home foods and 3 percent on at-home foods, will raise per capita food spending about 6 percent. Expansion of the Nation's population will drive growth in food demand and, combined with rising incomes and other demographic changes, is projected to boost total U.S. food spending 26.3 percent. On a national level, the slow but steady growth of the population will result in little variation among expenditure growth levels of individual food groups. The largest projected increase is for fruits, up 27.5 percent, while the smallest is for both beef and beverages, up 21.1 percent.Household food expenditures, income, demographics, projections, Consumer Expenditure Survey, Food Consumption/Nutrition/Food Safety,

    Reduction of dynamical biochemical reaction networks in computational biology

    Get PDF
    Biochemical networks are used in computational biology, to model the static and dynamical details of systems involved in cell signaling, metabolism, and regulation of gene expression. Parametric and structural uncertainty, as well as combinatorial explosion are strong obstacles against analyzing the dynamics of large models of this type. Multi-scaleness is another property of these networks, that can be used to get past some of these obstacles. Networks with many well separated time scales, can be reduced to simpler networks, in a way that depends only on the orders of magnitude and not on the exact values of the kinetic parameters. The main idea used for such robust simplifications of networks is the concept of dominance among model elements, allowing hierarchical organization of these elements according to their effects on the network dynamics. This concept finds a natural formulation in tropical geometry. We revisit, in the light of these new ideas, the main approaches to model reduction of reaction networks, such as quasi-steady state and quasi-equilibrium approximations, and provide practical recipes for model reduction of linear and nonlinear networks. We also discuss the application of model reduction to backward pruning machine learning techniques

    Belajar Menghargai Kearifan Lokal dari Yesus dalam Matius 22:32

    Full text link
    Churches in Indonesia live in ethnical and cultural diversity. We can find much local wisdom which lately continues to preserve. But not all churches want to receive local wisdom because there is an opinion that local culture is contrary to the Christian faith. Therefore in this paper I want to invite the churches in Indonesia to open space for local wisdom. My effort is encouraging the churches to look at the figure of Jesus, who popularized the local wisdom that called the tradition of Theos Patros. Theos Patros tradition is the oldest tradition of the nation of Israel and has been known since the era of the ancestors but is no longer popular in the time of Jesus. But Jesus re-popularized the tradition because that tradition has a high noble value in line with the emphasis of the Gospel of Matthew

    Future Healthcare Professionals’ Attitudes About the Sexuality of Women with Intellectual Disabilities

    Get PDF
    Women with intellectual disabilities (WID) experience a number of systemic barriers to healthcare related to their sexuality and sexual expression. Additionally, they are vulnerable to sexual abuse which could lead to conditions that would adversely affect their health and wellbeing. There is a need for healthcare professionals to be able to provide comprehensive sexual healthcare to WID, and this service is currently lacking. To begin to address this gap in available care, content on the sexuality of WID in courses taken by undergraduate future healthcare providers (FHP) needs to be developed. To provide the foundation of such a curriculum, this study assessed the attitudes towards the sexuality of WID of 47 undergraduate FHP using the Attitudes to Sexuality Questionnaire (Individuals with an Intellectual Disability), which includes 32 items having a 6-point Likert scale. With an overall mean score of 5.07, students showed overall agreement with statements affirming the rights and sexuality of WID. This finding suggests their likely acceptance of a curriculum that would include these topics. To build on these attitudes, educational recommendations are made to provide students with opportunities for: 1) clinical observations of healthcare professionals with expertise in caring for WID and 2) direct conversations with and exposure to WID in the classroom setting. KEYWORDS: Intellectual disability, Women, Sexuality, Healthcar

    Ceramics Analysis and Reliability Evaluation of Structures (CARES). Users and programmers manual

    Get PDF
    This manual describes how to use the Ceramics Analysis and Reliability Evaluation of Structures (CARES) computer program. The primary function of the code is to calculate the fast fracture reliability or failure probability of macroscopically isotropic ceramic components. These components may be subjected to complex thermomechanical loadings, such as those found in heat engine applications. The program uses results from MSC/NASTRAN or ANSYS finite element analysis programs to evaluate component reliability due to inherent surface and/or volume type flaws. CARES utilizes the Batdorf model and the two-parameter Weibull cumulative distribution function to describe the effect of multiaxial stress states on material strength. The principle of independent action (PIA) and the Weibull normal stress averaging models are also included. Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities are estimated from four-point bend bar or unifrom uniaxial tensile specimen fracture strength data. Parameter estimation can be performed for single or multiple failure modes by using the least-square analysis or the maximum likelihood method. Kolmogorov-Smirnov and Anderson-Darling goodness-of-fit tests, ninety percent confidence intervals on the Weibull parameters, and Kanofsky-Srinivasan ninety percent confidence band values are also provided. The probabilistic fast-fracture theories used in CARES, along with the input and output for CARES, are described. Example problems to demonstrate various feature of the program are also included. This manual describes the MSC/NASTRAN version of the CARES program

    Calculation of Weibull strength parameters, Batdorf flaw density constants and related statistical quantities using PC-CARES

    Get PDF
    This manual describes the operation and theory of the PC-CARES (Personal Computer-Ceramic Analysis and Reliability Evaluation of Structures) computer program for the IBM PC and compatibles running PC-DOS/MS-DOR OR IBM/MS-OS/2 (version 1.1 or higher) operating systems. The primary purpose of this code is to estimate Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities. Included in the manual is the description of the calculation of shape and scale parameters of the two-parameter Weibull distribution using the least-squares analysis and maximum likelihood methods for volume- and surface-flaw-induced fracture in ceramics with complete and censored samples. The methods for detecting outliers and for calculating the Kolmogorov-Smirnov and the Anderson-Darling goodness-of-fit statistics and 90 percent confidence bands about the Weibull line, as well as the techniques for calculating the Batdorf flaw-density constants are also described

    Cycles of length three and four in tournaments

    Get PDF
    Linial and Morgenstern conjectured that, among all nn-vertex tournaments with d(n3)d\binom{n}{3} cycles of length three, the number of cycles of length four is asymptotically minimized by a random blow-up of a transitive tournament with all but one part of equal size and one smaller part. We prove the conjecture for d1/36d\ge 1/36 by analyzing the possible spectrum of adjacency matrices of tournaments. We also demonstrate that the family of extremal examples is broader than expected and give its full description for d1/16d\ge 1/16

    Design of ceramic components with the NASA/CARES computer program

    Get PDF
    The ceramics analysis and reliability evaluation of structures (CARES) computer program is described. The primary function of the code is to calculate the fast-fracture reliability or failure probability of macro-scopically isotropic ceramic components. These components may be subjected to complex thermomechanical loadings, such as those found in heat engine applications. CARES uses results from MSC/NASTRAN or ANSYS finite-element analysis programs to evaluate how inherent surface and/or volume type flaws component reliability. CARES utilizes the Batdorf model and the two-parameter Weibull cumulative distribution function to describe the effects of multiaxial stress states on material strength. The principle of independent action (PIA) and the Weibull normal stress averaging models are also included. Weibull material strength parameters, the Batdorf crack density coefficient, and other related statistical quantities are estimated from four-point bend bar or uniform uniaxial tensile specimen fracture strength data. Parameter estimation can be performed for a single or multiple failure modes by using a least-squares analysis or a maximum likelihood method. Kolmogorov-Smirnov and Anderson-Darling goodness-to-fit-tests, 90 percent confidence intervals on the Weibull parameters, and Kanofsky-Srinivasan 90 percent confidence band values are also provided. Examples are provided to illustrate the various features of CARES

    Integrity of Ceramic Parts Predicted When Loads and Temperatures Fluctuate Over Time

    Get PDF
    Brittle materials are being used, and being considered for use, for a wide variety of high performance applications that operate in harsh environments, including static and rotating turbine parts for unmanned aerial vehicles, auxiliary power units, and distributed power generation. Other applications include thermal protection systems, dental prosthetics, fuel cells, oxygen transport membranes, radomes, and microelectromechanical systems (MEMS). In order for these high-technology ceramics to be used successfully for structural applications that push the envelope of materials capabilities, design engineers must consider that brittle materials are designed and analyzed differently than metallic materials. Unlike ductile metals, brittle materials display a stochastic strength response because of the combination of low fracture toughness and the random nature of the size, orientation, and distribution of inherent microscopic flaws. This plus the fact that the strength of a component under load may degrade over time because of slow crack growth means that a probabilistic-based life-prediction methodology must be used when the tradeoffs of failure probability, performance, and useful life are being optimized. The CARES/Life code (which was developed at the NASA Glenn Research Center) predicts the probability of ceramic components failing from spontaneous catastrophic rupture when these components are subjected to multiaxial loading and slow crack growth conditions. Enhancements to CARES/Life now allow for the component survival probability to be calculated when loading and temperature vary over time
    corecore