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Sample records for strength theory based

  1. Burst strength of tubing and casing based on twin shear unified strength theory.

    Science.gov (United States)

    Lin, Yuanhua; Deng, Kuanhai; Sun, Yongxing; Zeng, Dezhi; Liu, Wanying; Kong, Xiangwei; Singh, Ambrish

    2014-01-01

    The internal pressure strength of tubing and casing often cannot satisfy the design requirements in high pressure, high temperature and high H2S gas wells. Also, the practical safety coefficient of some wells is lower than the design standard according to the current API 5C3 standard, which brings some perplexity to the design. The ISO 10400: 2007 provides the model which can calculate the burst strength of tubing and casing better than API 5C3 standard, but the calculation accuracy is not desirable because about 50 percent predictive values are remarkably higher than real burst values. So, for the sake of improving strength design of tubing and casing, this paper deduces the plastic limit pressure of tubing and casing under internal pressure by applying the twin shear unified strength theory. According to the research of the influence rule of yield-to-tensile strength ratio and mechanical properties on the burst strength of tubing and casing, the more precise calculation model of tubing-casing's burst strength has been established with material hardening and intermediate principal stress. Numerical and experimental comparisons show that the new burst strength model is much closer to the real burst values than that of other models. The research results provide an important reference to optimize the tubing and casing design of deep and ultra-deep wells.

  2. Assessment of an improved multiaxial strength theory based on creep-rupture data for Inconel 600

    International Nuclear Information System (INIS)

    Huddleston, R.L.

    1993-01-01

    A new multiaxial strength theory incorporating three independent stress parameters was developed and reported by the author in 1984. It was formally incorporated into ASME Code Case N47-29 in 1990. The new theory provided significantly more accurate stress-rupture life predictions than obtained using the classical theories of von Mises, Tresca, and Rankins (maximum principal stress), for Types 304 and 316 stainless steel tested at 593 and 600 degrees C respectively under different biaxial stress states. Additional results for Inconel 600 specimens tested at 816 degrees C under tension-tension and tension-compression stress states are presented in this paper and show a factor of approximately 2.4 reduction in the scatter of predicted versus observed lives as compared to the classical theories of von Mises and Tresca and a factor of about 5 as compared to the Rankins theory. A key feature of the theory, which incorporates the maximum deviatoric stress, the first invariant of the stress tensor, and the second invariant of the deviatoric stress tensor, is its ability to distinguish between life under tensile versus compressive stress states

  3. Unified nano-mechanics based probabilistic theory of quasibrittle and brittle structures: I. Strength, static crack growth, lifetime and scaling

    Science.gov (United States)

    Le, Jia-Liang; Bažant, Zdeněk P.; Bazant, Martin Z.

    2011-07-01

    Engineering structures must be designed for an extremely low failure probability such as 10 -6, which is beyond the means of direct verification by histogram testing. This is not a problem for brittle or ductile materials because the type of probability distribution of structural strength is fixed and known, making it possible to predict the tail probabilities from the mean and variance. It is a problem, though, for quasibrittle materials for which the type of strength distribution transitions from Gaussian to Weibullian as the structure size increases. These are heterogeneous materials with brittle constituents, characterized by material inhomogeneities that are not negligible compared to the structure size. Examples include concrete, fiber composites, coarse-grained or toughened ceramics, rocks, sea ice, rigid foams and bone, as well as many materials used in nano- and microscale devices. This study presents a unified theory of strength and lifetime for such materials, based on activation energy controlled random jumps of the nano-crack front, and on the nano-macro multiscale transition of tail probabilities. Part I of this study deals with the case of monotonic and sustained (or creep) loading, and Part II with fatigue (or cyclic) loading. On the scale of the representative volume element of material, the probability distribution of strength has a Gaussian core onto which a remote Weibull tail is grafted at failure probability of the order of 10 -3. With increasing structure size, the Weibull tail penetrates into the Gaussian core. The probability distribution of static (creep) lifetime is related to the strength distribution by the power law for the static crack growth rate, for which a physical justification is given. The present theory yields a simple relation between the exponent of this law and the Weibull moduli for strength and lifetime. The benefit is that the lifetime distribution can be predicted from short-time tests of the mean size effect on

  4. Strengths-based Learning

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    -being. The Ph.D.-project in Strength-based learning took place in a Danish school with 750 pupils age 6-16 and a similar school was functioning as a control group. The presentation will focus on both the aware-explore-apply processes and the practical implications for the schools involved, and on measurable......Strength-based learning - Children͛s Character Strengths as Means to their Learning Potential͛ is a Ph.D.-project aiming to create a strength-based mindset in school settings and at the same time introducing strength-based interventions as specific tools to improve both learning and well...

  5. Applications of Strengths-Based Leadership Theory for the U.S. Army

    Science.gov (United States)

    2012-09-01

    Albert Bandura’s (1994) theory of self-efficacy also helps explain how optimization might take place. According to SBL theory, when individuals invest...improved productivity and satisfaction ( Bandura , 1994). In practice, consistent investment in talents by leaders and subordinates leads to the...References Bandura , A. (1994). Self-efficacy. In V. S. Ramachaudran (Ed.), Encyclopedia of human behavior (pp. 71-81). New York: Academic Press

  6. Unified strength theory and its applications

    CERN Document Server

    Yu, Mao-Hong

    2004-01-01

    This is a completely new theory dealing with the yield and failure of materials under multi-axial stresses. It provides a system of yield and failure criteria adopted for most materials, from metallic materials to rocks, concretes, soils, polymers etc. The Unified Strength Theory has been applied successfully to analyse the elastic limit, plastic limit capacities, the dynamic response behavior for some structures under static and moderate impulsive load, and may be implemented in some elasto-plastic finite element computer codes. The Unified Strength Theory is described in detail and by using this theory a series of results can be obtained. The Unified Strength Theory can improve the conservative Mohr-Coulomb Theory, and since intermediate principal stress is not taken into account in the Mohr-Coulomb theory and most experimental data is not pertainable to the Mohr-Coulomb Theory, a considerable economic benefit may be obtained. The book can also increase the effect of most commercial finite element computer ...

  7. Perturbation theory for arbitrary coupling strength?

    Science.gov (United States)

    Mahapatra, Bimal P.; Pradhan, Noubihary

    2018-03-01

    We present a new formulation of perturbation theory for quantum systems, designated here as: “mean field perturbation theory” (MFPT), which is free from power-series-expansion in any physical parameter, including the coupling strength. Its application is thereby extended to deal with interactions of arbitrary strength and to compute system-properties having non-analytic dependence on the coupling, thus overcoming the primary limitations of the “standard formulation of perturbation theory” (SFPT). MFPT is defined by developing perturbation about a chosen input Hamiltonian, which is exactly solvable but which acquires the nonlinearity and the analytic structure (in the coupling strength) of the original interaction through a self-consistent, feedback mechanism. We demonstrate Borel-summability of MFPT for the case of the quartic- and sextic-anharmonic oscillators and the quartic double-well oscillator (QDWO) by obtaining uniformly accurate results for the ground state of the above systems for arbitrary physical values of the coupling strength. The results obtained for the QDWO may be of particular significance since “renormalon”-free, unambiguous results are achieved for its spectrum in contrast to the well-known failure of SFPT in this case.

  8. Field-strength formulation of gauge theories. The Hamiltonian approach in the Abelian theory

    International Nuclear Information System (INIS)

    Mendel, E.; Durand, L.

    1984-01-01

    We develop a Hamiltonian approach to the field-strength or dual formation of the Abelian gauge theory in which the potential A/sup μ/ is eliminated as a dynamical variable. Our work is based on the covariant gauge x/sup μ/A/sub μ/(x) = 0 which allows a simple elimination of A/sup μ/ in terms of the field strengths F/sup munu/. We obtain complete results for the generating functional for the Green's functions of the theory, Z = Z[f,g], where f and g are nonlocal currents coupled to E and B, and illustrate some unfamiliar aspects of the new formalism

  9. Random matrix theory for transition strengths: Applications and open questions

    Science.gov (United States)

    Kota, V. K. B.

    2017-12-01

    Embedded random matrix ensembles are generic models for describing statistical properties of finite isolated interacting quantum many-particle systems. A finite quantum system, induced by a transition operator, makes transitions from its states to the states of the same system or to those of another system. Examples are electromagnetic transitions (then the initial and final systems are same), nuclear beta and double beta decay (then the initial and final systems are different) and so on. Using embedded ensembles (EE), there are efforts to derive a good statistical theory for transition strengths. With m fermions (or bosons) in N mean-field single particle levels and interacting via two-body forces, we have with GOE embedding, the so called EGOE(1+2). Now, the transition strength density (transition strength multiplied by the density of states at the initial and final energies) is a convolution of the density generated by the mean-field one-body part with a bivariate spreading function due to the two-body interaction. Using the embedding U(N) algebra, it is established, for a variety of transition operators, that the spreading function, for sufficiently strong interactions, is close to a bivariate Gaussian. Also, as the interaction strength increases, the spreading function exhibits a transition from bivariate Breit-Wigner to bivariate Gaussian form. In appropriate limits, this EE theory reduces to the polynomial theory of Draayer, French and Wong on one hand and to the theory due to Flambaum and Izrailev for one-body transition operators on the other. Using spin-cutoff factors for projecting angular momentum, the theory is applied to nuclear matrix elements for neutrinoless double beta decay (NDBD). In this paper we will describe: (i) various developments in the EE theory for transition strengths; (ii) results for nuclear matrix elements for 130Te and 136Xe NDBD; (iii) important open questions in the current form of the EE theory.

  10. Restorative Justice as Strength-Based Accountability

    Science.gov (United States)

    Ball, Robert

    2003-01-01

    This article compares strength-based and restorative justice philosophies for young people and their families. Restorative justice provides ways to respond to crime and harm that establish accountability while seeking to reconcile members of a community. Restorative approaches are an important subset of strength-based interventions.

  11. The Scope of Usage-based Theory

    OpenAIRE

    Paul eIbbotson

    2013-01-01

    Usage-based approaches typically draw on a relatively small set of cognitive processes, such as categorization, analogy, and chunking to explain language structure and function. The goal of this paper is to first review the extent to which the “cognitive commitment” of usage-based theory has had success in explaining empirical findings across domains, including language acquisition, processing, and typology. We then look at the overall strengths and weaknesses of usage-based theory and highli...

  12. Theory-Based Stakeholder Evaluation

    Science.gov (United States)

    Hansen, Morten Balle; Vedung, Evert

    2010-01-01

    This article introduces a new approach to program theory evaluation called theory-based stakeholder evaluation or the TSE model for short. Most theory-based approaches are program theory driven and some are stakeholder oriented as well. Practically, all of the latter fuse the program perceptions of the various stakeholder groups into one unitary…

  13. Measurements of proton strength functions and comparisons with theory

    International Nuclear Information System (INIS)

    Arai, E.; Ozawa, Y.

    1986-01-01

    Using a high-resolution proton beam of the Tokyo Institute of Technology Van de Graaff, precise measurements of elastic and inelastic scattering cross sections have been performed in the past 15 years. By directly observing individual proton resonances, their spins, parities and proton decay widths were deduced. From these experiments we have evaluated (1) proton strength functions in terms of target mass number and of incident proton energy and (2) Coulomb matrix elements for split analogue resonances. (orig.)

  14. Adult active transportation: adding habit strength to the Theory of Planned Behavior

    NARCIS (Netherlands)

    de Bruijn, G.J.; Kremers, S.P.J.; Singh, A.; van den Putte, B.; van Mechelen, W.

    2009-01-01

    Background: Many health behaviors have a history of repetition and, as a result, may become habitual. Because including a measure of habit strength may add depth to current theoretical models on health behavior, the present study explored the issue of habit strength within the context of the theory

  15. Using Mindfulness-Based Strengths Practices with Gifted Populations

    Science.gov (United States)

    Sharp, Jennifer E.; Niemiec, Ryan M.; Lawrence, Christopher

    2017-01-01

    Mindfulness and character strengths are synergistic tools that work together to cultivate well-being. Mindfulness-Based Strengths Practice (MBSP) combines the research and practice of these constructs to enhance well-being, meaning, and engagement. In this article, research supporting how mindfulness and character strengths may benefit the gifted…

  16. Density Profiles, Energy, and Oscillation Strength of a Quantum Dot in Two Dimensions with a Harmonic Oscillator External Potential using an Orbital-free Energy Functional Based on Thomas–Fermi Theory

    Directory of Open Access Journals (Sweden)

    Suhufa Alfarisa

    2016-03-01

    Full Text Available This research aims i to determine the density profile and calculate the ground state energy of a quantum dot in two dimensions (2D with a harmonic oscillator potential using orbital-free density functional theory, and ii to understand the effect of the harmonic oscillator potential strength on the electron density profiles in the quantum dot. This study determines the total energy functional of the quantum dot that is a functional of the density that depends only on spatial variables. The total energy functional consists of three terms. The first term is the kinetic energy functional, which is the Thomas–Fermi approximation in this case. The second term is the external potential. The harmonic oscillator potential is used in this study. The last term is the electron–electron interactions described by the Coulomb interaction. The functional is formally solved to obtain the electron density as a function of spatial variables. This equation cannot be solved analytically, and thus a numerical method is used to determine the profile of the electron density. Using the electron density profiles, the ground state energy of the quantum dot in 2D can be calculated. The ground state energies obtained are 2.464, 22.26, 90.1957, 252.437, and 496.658 au for 2, 6, 12, 20, and 56 electrons, respectively. The highest electron density is localized close to the middle of the quantum dot. The density profiles decrease with the increasing distance, and the lowest density is at the edge of the quantum dot. Generally, increasing the harmonic oscillator potential strength reduces the density profiles around the center of the quantum dot.

  17. Study on creep of fiber reinforced ultra-high strength concrete based on strength

    Science.gov (United States)

    Peng, Wenjun; Wang, Tao

    2018-04-01

    To complement the creep performance of ultra-high strength concrete, the long creep process of fiber reinforced concrete was studied in this paper. The long-term creep process and regularity of ultra-high strength concrete with 0.5% PVA fiber under the same axial compression were analyzed by using concrete strength (C80/C100/C120) as a variable. The results show that the creep coefficient of ultra-high strength concrete decreases with the increase of concrete strength. Compared with ACI209R (92), GL2000 models, it is found that the predicted value of ACI209R (92) are close to the experimental value, and the creep prediction model suitable for this experiment is proposed based on ACI209R (92).

  18. Effectiveness of a Brief Intervention Using Process-Based Mental Simulations in Promoting Muscular Strength in Physical Education

    Science.gov (United States)

    Koka, Andre

    2017-01-01

    This study examined the effectiveness of a brief theory-based intervention on muscular strength among adolescents in a physical education setting. The intervention adopted a process-based mental simulation technique. The self-reported frequency of practising for and actual levels of abdominal muscular strength/endurance as one component of…

  19. Study of the strength characteristics of protein-based lightweight ...

    African Journals Online (AJOL)

    Compressive strength test was carried out on the protein-based lightweight foamed concrete produced with cement partially replaced by rice husk ash to ascertain its strength characteristics. Standard concrete cubes of 150 x 150 x 150 mm were produced using ordinary Portland cement (OPC), fine aggregate, aqueous ...

  20. Experimental data base for gamma-ray strength functions

    International Nuclear Information System (INIS)

    Kopecky, J.

    1999-01-01

    Theoretical and experimental knowledge of γ-ray strength functions is a very important ingredient for description and calculation of photon production data in all reaction channels. This study focusses on experimental γ-ray strength functions, collected over a period of about 40 years and based on measurements of partial radiative widths

  1. The Scope of Usage-based Theory

    Directory of Open Access Journals (Sweden)

    Paul eIbbotson

    2013-05-01

    Full Text Available Usage-based approaches typically draw on a relatively small set of cognitive processes, such as categorization, analogy and chunking to explain language structure and function. The goal of this paper is to first review the extent to which the ‘cognitive commitment’ of usage-based theory has had success in explaining empirical findings across domains, including language acquisition, processing and typology. We then look at the overall strengths and weaknesses of usage-based theory and highlight where there are significant debates. Finally, we draw special attention to a set of culturally generated structural patterns that seem to lie beyond the explanation of core usage-based cognitive processes. In this context we draw a distinction between cognition permitting language structure versus cognition entailing language structure. As well as addressing the need for greater clarity on the mechanisms of generalizations and the fundamental units of grammar, we suggest that integrating culturally generated structures within existing cognitive models of use will generate tighter predictions about how language works.

  2. Should Psychosocial Safety Climate Theory Be Extended to Include Climate Strength?

    Science.gov (United States)

    Afsharian, Ali; Zadow, Amy; Dollard, Maureen F; Dormann, Christian; Ziaian, Tahereh

    2017-08-31

    Psychosocial safety climate (PSC; climate for psychological health) is an organizational antecedent to work conditions articulated in the job demands-resources model. We responded to calls for broader consideration of organizational climate in terms of both climate level and strength. We tested PSC level and strength as main and interactive predictors of work conditions, psychological health, and engagement. Using multilevel analysis and cross-sectional data, the effects of unit-level PSC constructs were investigated in 21 hospital work units (n = 249 employees) in Australia. The correlation between PSC levels (measured at the unit mean) and PSC strength (measured as unit -1 × SD) was moderate and positive, suggesting that ceiling effects of PSC scores were not problematic. PSC level was a better predictor than PSC strength or their interactions for job demands (psychological and emotional demands), job resources (e.g., skill discretion and organizational support), and health (emotional exhaustion). For engagement, the interaction was significant-improving engagement, therefore, benefits from high levels of PSC and PSC strength within the work units. So, in answer to the research question regarding PSC theory extension, "it depends on the outcome." Research limitations are acknowledged, and the potential of the PSC model to guide the reduction of workplace psychosocial risk factors and the negative consequences is discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  3. Strength Performance of Blended Ash Based Geopolymer Mortar

    Science.gov (United States)

    Zahib, Zaidahtulakmal M.; Kamaruddin, Kartini; Saman, Hamidah M.

    2018-03-01

    Geopolymer is a based on inorganic alumino-silicate binder system. Geopolymeric materials are formed using materials that containing silica and aluminium such as fly ash and rice husk ash, which activated by alkaline solution. This paper presents the study on the effect of replacement of SSA in RHA based geopolymer, types of curing and different molarity of NaOH used on the strength of Sewage Sludge Ash (SSA) and Rice Husk Ash (RHA) based geopolymer mortar incorporating with three (3) different mix proportions. Based geopolymer mortar was synthesized from treated sewage sludge and rice husk undergoing incineration process in producing ashes, activated with sodium silicate and sodium hydroxide solution by ratio of 2.5:1 and solution to ash ratio of 1:1. Molarity of 8M and 10M NaOH were used. The percentages of SSA replacement were 0%, 10% and 20% by weight. Compressive strength was conducted at age 7, 14 and 28 days to see the development of strength with two curing regimes, which are air curing and oven curing (60°C for 24 hours). From the research conducted, the ultimate compressive strength (6.28MPa) was obtained at zero replacement of SSA taken at 28 days of oven curing with 10M of NaOH. This shows that RHA, which is rich in silica content is enough to enhance the strength of geopolymer mortar especially with high molarity of NaOH.

  4. Which strengths-based practice? Reconciling strengths-based practice and mandated authority in child protection work.

    Science.gov (United States)

    Oliver, Carolyn; Charles, Grant

    2015-04-01

    The recent application of strengths-based practice in child protection settings has been accompanied by evidence of inconsistent implementation and concerns that the approach is incompatible with statutory work. Few studies have moved beyond asking whether child protection workers are implementing strengths-based practice to explore why the approach is enacted as it is. This article describes a mixed methods study using an online survey and interviews to elicit from 225 statutory child protection workers in a large Canadian agency how they applied strengths-based ideas and why they did what they did. The authors found that although strengths-based practice was popular, 70 percent of participants believed that it was not always applicable to child protection work. Participants described five distinct versions of the approach, only one of which was fully congruent with their mandated role. The study suggests that the common conflation of strengths-based and solution-focused approaches ignores important differences in the conceptualization of practitioner authority and leaves practitioners attempting to implement versions ofstrengths-based practice that do not fit statutory child protection work. Only when practitioners choose solution-focused models that support their use of mandated authority is consistent implementation a reasonable expectation.

  5. Analysis on geometry-aware received signal strength based ...

    African Journals Online (AJOL)

    These handle different scenarios such as environment, adaptation, hybridization and the choice of context is dependent on user requirements. This paper present geometry-aware received signal strength (RSS) based positioning techniques where the influences of the geometries of the BSs (where location estimation ...

  6. School-Based Sexuality Education in Portugal: Strengths and Weaknesses

    Science.gov (United States)

    Rocha, Ana Cristina; Leal, Cláudia; Duarte, Cidália

    2016-01-01

    Portugal, like many other countries, faces obstacles regarding school-based sexuality education. This paper explores Portuguese schools' approaches to implementing sexuality education at a local level, and provides a critical analysis of potential strengths and weaknesses. Documents related to sexuality education in a convenience sample of 89…

  7. Strength-based leadership coaching in organizations an evidence-based guide to positive leadership development

    CERN Document Server

    MacKie, Doug

    2016-01-01

    Positive organizational psychology, with its focus on the identification and development of strengths, is a natural ally to executive development and leadership coaching. However, this approach is only just beginning to come to the attention of organizations and consequently, the research base for strength-based coaching is in its early stages of development. Strength-based Leadership Coaching in Organizations reviews strength-based approaches to positive leadership development and evaluates the evidence for their effectiveness, critically assesses their apparent distinctiveness and considers how strengths can be reliably assessed and developed in their organizational context. This book reviews key areas of leader and team development are reviewed and outlines and describes a model of strengths development in organizations. The application of strength-based leadership coaching will be discussed from the managerial and external perspective within the context of career stage, seniority, role challenges and orga...

  8. Finding significantly connected voxels based on histograms of connection strengths

    DEFF Research Database (Denmark)

    Kasenburg, Niklas; Pedersen, Morten Vester; Darkner, Sune

    2016-01-01

    We explore a new approach for structural connectivity based segmentations of subcortical brain regions. Connectivity based segmentations are usually based on fibre connections from a seed region to predefined target regions. We present a method for finding significantly connected voxels based...... on the distribution of connection strengths. Paths from seed voxels to all voxels in a target region are obtained from a shortest-path tractography. For each seed voxel we approximate the distribution with a histogram of path scores. We hypothesise that the majority of estimated connections are false-positives...... and that their connection strength is distributed differently from true-positive connections. Therefore, an empirical null-distribution is defined for each target region as the average normalized histogram over all voxels in the seed region. Single histograms are then tested against the corresponding null...

  9. Investigating Strength and Frequency Effects in Recognition Memory Using Type-2 Signal Detection Theory

    Science.gov (United States)

    Higham, Philip A.; Perfect, Timothy J.; Bruno, Davide

    2009-01-01

    Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower…

  10. Accumulative job demands and support for strength use: Fine-tuning the job demands-resources model using conservation of resources theory.

    Science.gov (United States)

    van Woerkom, Marianne; Bakker, Arnold B; Nishii, Lisa H

    2016-01-01

    Absenteeism associated with accumulated job demands is a ubiquitous problem. We build on prior research on the benefits of counteracting job demands with resources by focusing on a still untapped resource for buffering job demands-that of strengths use. We test the idea that employees who are actively encouraged to utilize their personal strengths on the job are better positioned to cope with job demands. Based on conservation of resources (COR) theory, we hypothesized that job demands can accumulate and together have an exacerbating effect on company registered absenteeism. In addition, using job demands-resources theory, we hypothesized that perceived organizational support for strengths use can buffer the impact of separate and combined job demands (workload and emotional demands) on absenteeism. Our sample consisted of 832 employees from 96 departments (response rate = 40.3%) of a Dutch mental health care organization. Results of multilevel analyses indicated that high levels of workload strengthen the positive relationship between emotional demands and absenteeism and that support for strength use interacted with workload and emotional job demands in the predicted way. Moreover, workload, emotional job demands, and strengths use interacted to predict absenteeism. Strengths use support reduced the level of absenteeism of employees who experienced both high workload and high emotional demands. We conclude that providing strengths use support to employees offers organizations a tool to reduce absenteeism, even when it is difficult to redesign job demands. (c) 2016 APA, all rights reserved).

  11. Theory-Based Evaluation Meets Ambiguity

    DEFF Research Database (Denmark)

    Dahler-Larsen, Peter

    2017-01-01

    As theory-based evaluation (TBE) engages in situations where multiple stakeholders help develop complex program theory about dynamic phenomena in politically contested settings, it becomes difficult to develop and use program theory without ambiguity. The purpose of this article is to explore...... ambiguity as a fruitful perspective that helps TBE face current challenges. Literatures in organization theory and political theory are consulted in order to cultivate the concept of ambiguity. Janus variables (which work in two ways) and other ambiguous aspects of program theories are classified...... and exemplified. Stances towards ambiguity are considered, as are concrete steps that TBE evaluators can take to identify and deal with ambiguity in TBE....

  12. On the Strength of the Carbon Nanotube-Based Space Elevator Cable: From Nano- to Mega-Mechanics

    OpenAIRE

    Pugno, Nicola M.

    2006-01-01

    In this paper different deterministic and statistical models, based on new quantized theories proposed by the author, are presented to estimate the strength of a real, thus defective, space elevator cable. The cable, of ~100 megameters in length, is composed by carbon nanotubes, ~100 nanometers long: thus, its design involves from the nano- to the mega-mechanics. The predicted strengths are extensively compared with the experiments and the atomistic simulations on carbon nanotubes available i...

  13. MOTIVATING ENGLISH TEACHERS BASED ON THE BASIC NEEDS THEORY AND AN EXPECTANCY THEORY

    Directory of Open Access Journals (Sweden)

    Hidayatus Sholihah

    2017-08-01

    Full Text Available There are two main motivation theories. a hierarchy of basic needs theory,  and an expectancy theory. In a Hyrarchy of basic needs theory, Maslow has stated that the basic needs as a main behaviour direction are structured into a hierarchy. There are five basic human needs.  The first: Physiological needs such as: salary, bonus or working condition. The second: the safety needs, such as: safe job environment, job security or health cover. The third, social needs, such as  union and team work. The next is self esteem, such as getting an award, medal, certificate or any other recognisition. Then the last is self actualization, for example is by providing an opportunity to share knowledge, skills and eprerience. The evaluation of this theory are: there is no spiritual needs as human basic needs is a main weakness of this theory. Then it is possible that different level of  needs  have to be satisfied in the same time, or not in hierarchy level or, not always have to be fulfilled in order. The next motivation theory is an Expectancy Theory. This theory is based on three main factors. The first factor is: English teachers will be motivated to work harder if they have a good perception to their own competences in accordance with their job. The second, individual motivation depends on the rewards given when they finish a  particular job. Finally, it also depends on their regards to the rewards given from the job that they do. Expectancy theory is a good theory, however, it is not easy to be implemented because the principals should provide various types of reward to satisfy the expectation of their English teachers. Considering the strengths and weaknesses of these two theories, it is better to combine both of them in the practice to get more effective results.

  14. Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance

    OpenAIRE

    Wirth Klaus; Keiner Michael; Hartmann Hagen; Sander Andre; Mickel Christoph

    2016-01-01

    Abstract The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ? 2.5 years; body height: 181.0 ? 6.8 cm; body mass: 80.2 ? 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were...

  15. A unified bond theory, probabilistic meso-scale modeling, and experimental validation of deformed steel rebar in normal strength concrete

    Science.gov (United States)

    Wu, Chenglin

    Bond between deformed rebar and concrete is affected by rebar deformation pattern, concrete properties, concrete confinement, and rebar-concrete interfacial properties. Two distinct groups of bond models were traditionally developed based on the dominant effects of concrete splitting and near-interface shear-off failures. Their accuracy highly depended upon the test data sets selected in analysis and calibration. In this study, a unified bond model is proposed and developed based on an analogy to the indentation problem around the rib front of deformed rebar. This mechanics-based model can take into account the combined effect of concrete splitting and interface shear-off failures, resulting in average bond strengths for all practical scenarios. To understand the fracture process associated with bond failure, a probabilistic meso-scale model of concrete is proposed and its sensitivity to interface and confinement strengths are investigated. Both the mechanical and finite element models are validated with the available test data sets and are superior to existing models in prediction of average bond strength (rib spacing-to-height ratio of deformed rebar. It can accurately predict the transition of failure modes from concrete splitting to rebar pullout and predict the effect of rebar surface characteristics as the rib spacing-to-height ratio increases. Based on the unified theory, a global bond model is proposed and developed by introducing bond-slip laws, and validated with testing of concrete beams with spliced reinforcement, achieving a load capacity prediction error of less than 26%. The optimal rebar parameters and concrete cover in structural designs can be derived from this study.

  16. Coupling Effect of Intruding Water and Inherent Gas on Coal Strength Based on the Improved (Mohr-Coulomb Failure Criterion

    Directory of Open Access Journals (Sweden)

    Yiyu Lu

    2016-11-01

    Full Text Available When employing hydraulic processes to increase gas drainage efficiency in underground coal mines, coal seams become a three-phase medium, containing water intruding into the coal pores with the inherent occurrence of gas. This can change the stress state of the coal and cause instability. This work studied the mechanical properties of coal containing water and gas and derived an appropriate failure criterion. Based on mixture theory of unsaturated porous media, the effective stress of coal, considering the interaction of water and gas, was analyzed, and the failure criterion established by combining this with the Mohr–Coulomb criterion. By introducing the stress factor of matrix suction and using fitted curves of experimentally determined matrix suction and moisture content, the relationships between coal strength, gas pressure, and moisture content were determined. To verify the established strength theory, a series of triaxial compression strength tests of coal containing water and gas were carried out on samples taken from the Songzao, Pingdingshan, and Tashan mines in China. The experimental results correlated well with the theoretical predictions. The results showed a linear decrease in the peak strength of coal with increasing gas pressure and an exponential reduction in peak strength with increasing moisture content. The strength theory of coal containing water and gas can become an important part of multiphase medium damage theory.

  17. Nanotechnology strength indicators: international rankings based on US patents

    Science.gov (United States)

    Marinova, Dora; McAleer, Michael

    2003-01-01

    Technological strength indicators (TSIs) based on patent statistics for 1975-2000 are used to analyse patenting of nanotechnology in the USA, and to compile international rankings for the top 12 foreign patenting countries (namely Australia, Canada, France, Germany, Great Britain, Italy, Japan, Korea, the Netherlands, Sweden, Switzerland and Taiwan). As the indicators are not directly observable, various proxy variables are used, namely the technological specialization index for national priorities, patent shares for international presence, citation rate for the contribution of patents to knowledge development and rate of assigned patents for potential commercial benefits. The best performing country is France, followed by Japan and Canada. It is shown that expertise and strength in nanotechnology are not evenly distributed among the technologically advanced countries, with the TSIs revealing different emphases in the development of nanotechnology.

  18. Bond strength test of acrylic artificial teeth with prosthetic base

    Directory of Open Access Journals (Sweden)

    Erna Kurnikasari

    2008-07-01

    Full Text Available Denture consists of acrylic artificial teeth and acrylic prothesis base bond chemically with a bond strength of 315 kgF/cm2. Most of the commercial acrylic artificial teeth do not specify their specifications and all of those acrylic artificial teeth do not include mechanical data (bond strength. The aim of this study is to discover which acrylic artificial teeth meet ADA specification no. 15. This study is a descriptive analytic study performed to 5 acrylic artificial teeth posterior brands commonly used by dentists and technicians. From each brand, 3 sample teeth were taken. The acrylic artificial teeth were prepared into a rectangular shape and were attached between acrylic prothesis base simulation and jigs. The sample was given tensile load using a Universal Testing Machine. The amount of force that causes the teeth to be fractured was recorded and the bond strength was calculated. The results of the study show that the average value for the five acrylic artificial teeth for the five brands were as followed: Brand A, 125.993 kgF/cm2; B, 188.457 kgF/cm2; C, 175.880 kgF/cm2; D, 153.373 kgF/cm2; E, 82.839 kgF/cm2. The data can be tested statistically by using One Way ANOVA test and Dunnett test (alpha = 0.05. From the study, it is concluded that the five acrylic artificial teeth have a bond strength below the ADA specification no. 15.

  19. Comparison and Analysis of Steel Frame Based on High Strength Column and Normal Strength Column

    Science.gov (United States)

    Liu, Taiyu; An, Yuwei

    2018-01-01

    The anti-seismic performance of high strength steel has restricted its industrialization in civil buildings. In order to study the influence of high strength steel column on frame structure, three models are designed through MIDAS/GEN finite element software. By comparing the seismic performance and economic performance of the three models, the three different structures are comprehensively evaluated to provide some references for the development of high strength steel in steel structure.

  20. On the strength of the carbon nanotube-based space elevator cable: from nanomechanics to megamechanics

    Energy Technology Data Exchange (ETDEWEB)

    Pugno, Nicola M [Department of Structural Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 (Italy)

    2006-08-23

    In this paper various deterministic and statistical models, based on new quantized theories proposed by the author, are presented for estimating the strength of a real, and thus defective, space elevator cable. The cable, {approx}100 000 km in length, is composed of carbon nanotubes, {approx}100 nm long: thus, its design involves nanomechanics and megamechanics. The predicted strengths are extensively compared with the experimental and atomistic simulation results for carbon nanotubes available in the literature. All these approaches unequivocally suggest that the megacable strength will be reduced by a factor at least of {approx}70% with respect to the theoretical nanotube strength, today (erroneously) assumed in the cable design. The reason is the unavoidable presence of defects in so huge a cable. Preliminary in-silicon tensile experiments confirm the same finding. The deduced strength reduction is sufficient to place in doubt the effective realization of the space elevator, that if built as designed today will certainly break (in the author's opinion). The mechanics of the cable is also revised and possible damage sources discussed.

  1. Uses of dipole oscillator strength sum rules in second order perturbation theory

    International Nuclear Information System (INIS)

    Struensee, M.C.

    1984-01-01

    Certain moments of the dipole oscillator strength distribution of atoms and molecules can be calculated from theory (using sum rules) or deduced from experiment. The present work describes the use of these moments to construct effective distributions which lead to bounds and estimates of physical properties of interest. Asymptotic analysis is then used to obtain the high energy behavior of the oscillator strength density and a previously unknown sum rule for atoms and molecules. A new type of effective distribution, which incorporates the information concerning the asymptotic behavior and the new sum rule, is suggested. This new type of distribution is used to calculate the logarithmic mean excitation energies for the ground states of atomic hydrogen, atomic helium and the negative hydrogen ion. The calculations for atomic helium and the negative hydrogen ion require the evaluation of certain ground state expectation values. These have been calculated using high accuracy wavefunctions containing the nonconventional terms shown by Fock to be necessary for a correct analytic expansion when both electrons are near the nucleus

  2. Roll force prediction of high strength steel using foil rolling theory in cold skin pass rolling

    International Nuclear Information System (INIS)

    Song, Gil Ho; Jung, Jae Chook

    2013-01-01

    Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high strength steel below TS 980 MPa in skin pass rolling

  3. Compressive strength and hydrolytic stability of fly ash based geopolymers

    Directory of Open Access Journals (Sweden)

    Nikolić Irena

    2013-01-01

    Full Text Available The process of geopolymerization involves the reaction of solid aluminosilicate materials with highly alkaline silicate solution yielding an aluminosilicate inorganic polymer named geopolymer, which may be successfully applied in civil engineering as a replacement for cement. In this paper we have investigated the influence of synthesis parameters: solid to liquid ratio, NaOH concentration and the ratio of Na2SiO3/NaOH, on the mechanical properties and hydrolytic stability of fly ash based geopolymers in distilled water, sea water and simulated acid rain. The highest value of compressive strength was obtained using 10 mol dm-3 NaOH and at the Na2SiO3/NaOH ratio of 1.5. Moreover, the results have shown that mechanical properties of fly ash based geopolymers are in correlation with their hydrolytic stability. Factors that increase the compressive strength also increase the hydrolytic stability of fly ash based geopolymers. The best hydrolytic stability of fly ash based geopolymers was shown in sea water while the lowest stability was recorded in simulated acid rain. [Projekat Ministarstva nauke Republike Srbije, br. 172054 i Nanotechnology and Functional Materials Center, funded by the European FP7 project No. 245916

  4. Vocation in theology-based nursing theories.

    Science.gov (United States)

    Lundmark, Mikael

    2007-11-01

    By using the concepts of intrinsicality/extrinsicality as analytic tools, the theology-based nursing theories of Ann Bradshaw and Katie Eriksson are analyzed regarding their explicit and/or implicit understanding of vocation as a motivational factor for nursing. The results show that both theories view intrinsic values as guarantees against reducing nursing practice to mechanistic applications of techniques and as being a way of reinforcing a high ethical standard. The theories explicitly (Bradshaw) or implicitly (Eriksson) advocate a vocational understanding of nursing as being essential for nursing theories. Eriksson's theory has a potential for conceptualizing an understanding of extrinsic and intrinsic motivational factors for nursing but one weakness in the theory could be the risk of slipping over to moral judgments where intrinsic factors are valued as being superior to extrinsic. Bradshaw's theory is more complex and explicit in understanding the concept of vocation and is theologically more plausible, although also more confessional.

  5. Tough hybrid ceramic-based material with high strength

    International Nuclear Information System (INIS)

    Guo, Shuqi; Kagawa, Yutaka; Nishimura, Toshiyuki

    2012-01-01

    This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB 2 -based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB 2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

  6. Advanced nickel base alloys for high strength, corrosion applications

    Science.gov (United States)

    Flinn, J.E.

    1998-11-03

    Improved nickel-base alloys of enhanced strength and corrosion resistance, produced by atomization of an alloy melt under an inert gas atmosphere and of composition 0--20Fe, 10--30Cr, 2--12Mo, 6 max. Nb, 0.05--3 V, 0.08 max. Mn, 0.5 max. Si, less than 0.01 each of Al and Ti, less than 0.05 each of P and S, 0.01--0.08C, less than 0.2N, 0.1 max. 0, bal. Ni. 3 figs.

  7. Power Load Prediction Based on Fractal Theory

    OpenAIRE

    Jian-Kai, Liang; Cattani, Carlo; Wan-Qing, Song

    2015-01-01

    The basic theories of load forecasting on the power system are summarized. Fractal theory, which is a new algorithm applied to load forecasting, is introduced. Based on the fractal dimension and fractal interpolation function theories, the correlation algorithms are applied to the model of short-term load forecasting. According to the process of load forecasting, the steps of every process are designed, including load data preprocessing, similar day selecting, short-term load forecasting, and...

  8. Benchmarks for electronically excited states: Time-dependent density functional theory and density functional theory based multireference configuration interaction

    DEFF Research Database (Denmark)

    Silva-Junior, Mario R.; Schreiber, Marko; Sauer, Stephan P. A.

    2008-01-01

    Time-dependent density functional theory (TD-DFT) and DFT-based multireference configuration interaction (DFT/MRCI) calculations are reported for a recently proposed benchmark set of 28 medium-sized organic molecules. Vertical excitation energies, oscillator strengths, and excited-state dipole...

  9. Wavelet-Based Quantum Field Theory

    Directory of Open Access Journals (Sweden)

    Mikhail V. Altaisky

    2007-11-01

    Full Text Available The Euclidean quantum field theory for the fields $phi_{Delta x}(x$, which depend on both the position $x$ and the resolution $Delta x$, constructed in SIGMA 2 (2006, 046, on the base of the continuous wavelet transform, is considered. The Feynman diagrams in such a theory become finite under the assumption there should be no scales in internal lines smaller than the minimal of scales of external lines. This regularisation agrees with the existing calculations of radiative corrections to the electron magnetic moment. The transition from the newly constructed theory to a standard Euclidean field theory is achieved by integration over the scale arguments.

  10. Living better with dementia: strengths-based social work practice and dementia care.

    Science.gov (United States)

    McGovern, Justine

    2015-01-01

    This article first argues that quality of life is possible despite the onset of dementia in late life. It also demonstrates how core concepts of social work practice, such as family systems theory, the strengths perspective, and use of self, can be applied to practice with dementia-affected persons. In addition, it provides practical suggestions for supporting care partners in nurturing "we-ness", focusing on what remains rather than was is lost, and remaining authentic. When strengths-based social work practice is integrated into dementia care protocols, wellbeing can increase. As a result, the more than 40 million persons worldwide who are affected by dementia do not have to resign themselves to the despair, devastation and inevitable demise of quality of life that dominate perception of the illness.

  11. Investigating strength and frequency effects in recognition memory using type-2 signal detection theory.

    Science.gov (United States)

    Higham, Philip A; Perfect, Timothy J; Bruno, Davide

    2009-01-01

    Criterion- versus distribution-shift accounts of frequency and strength effects in recognition memory were investigated with Type-2 signal detection receiver operating characteristic (ROC) analysis, which provides a measure of metacognitive monitoring. Experiment 1 demonstrated a frequency-based mirror effect, with a higher hit rate and lower false alarm rate, for low frequency words compared with high frequency words. In Experiment 2, the authors manipulated item strength with repetition, which showed an increased hit rate but no effect on the false alarm rate. Whereas Type-1 indices were ambiguous as to whether these effects were based on a criterion- or distribution-shift model, the two models predict opposite effects on Type-2 distractor monitoring under some assumptions. Hence, Type-2 ROC analysis discriminated between potential models of recognition that could not be discriminated using Type-1 indices alone. In Experiment 3, the authors manipulated Type-1 response bias by varying the number of old versus new response categories to confirm the assumptions made in Experiments 1 and 2. The authors conclude that Type-2 analyses are a useful tool for investigating recognition memory when used in conjunction with more traditional Type-1 analyses.

  12. Saturated fat consumption and the Theory of Planned Behaviour: exploring additive and interactive effects of habit strength

    NARCIS (Netherlands)

    de Bruijn, G.J.; Kroeze, W.; Oenema, O.; Brug, J.

    2008-01-01

    The additive and interactive effects of habit strength in the explanation of saturated fat intake were explored within the framework of the Theory of Planned Behaviour (TPB). Cross-sectional data were gathered in a Dutch adult sample (n = 764) using self-administered questionnaires and analyzed

  13. Accounting bases of theory: Why they matter

    Directory of Open Access Journals (Sweden)

    Zafeer Nagdee

    2016-11-01

    Full Text Available It is widely agreed that contemporary accounting practice is largely based on the application of professional accounting standards rather than on the application of sound, academic bases of theory. This has led to uncertainty within the field which has in turn inhibited the ability of accounting to develop into a more robust academic discipline. In conducting a thematic analysis of existing literature, this study will identify and expand on three key themes which will collectively establish the argument positing that a lacking basis of accounting theory has impaired the scholastic development of accounting practice worldwide. By introducing this argument to the academic community, this study will expose the economic risks associated with accounting’s absent bases of theory and will consequently add value by highlighting the need for additional research into the development, clarification and refinement of accounting theories that will result in more useful accounting practices worldwide

  14. Fatigue strength reduction factors for welds based on nondestructive examination

    International Nuclear Information System (INIS)

    Hechmer, J.L.; Kuhn, E.J. III

    1999-01-01

    Based on the author's hypothesis that nondestructive examination (NDE) has a major role in predicting the fatigue life of pressure vessels, a project was initiated to develop a defined relationship between NDE and fatigue strength reduction factors (FSRF). Even though a relationship should apply to both base metal and weld metal, the project was limited to weld metal because NDE for base metal is reasonably well established, whereas NDE for weld metal is more variable, depending on application. A matrix of FSRF was developed based on weld type (full penetration, partial penetration, and fillet weld) versus the NDE that is applied. The NDE methods that are included are radiographic testing (RT), ultrasonic testing (UT), magnetic particle testing (MT), dye penetrant testing (PT), and visual testing (VT). The first two methods (RT and UT) are volumetric examinations, and the remaining three are surface examinations. Seven combinations of volumetric and surface examinations were defined; thus, seven levels of FSRF are defined. Following the initial development of the project, a PVRC (Pressure Vessel Research Council) grant was obtained for the purpose of having a broad review. The report (Hechmer, 1998) has been accepted by PVRC. This paper presents the final matrix, the basis for the FSRF, and key definitions for accurate application of the FSRF matrix. A substantial amount of additional information is presented in the PVRC report (Hechmer, 1998)

  15. Motivated Implicit Theories of Personality: My Weaknesses Will Go Away, but My Strengths Are Here to Stay.

    Science.gov (United States)

    Steimer, Andreas; Mata, André

    2016-04-01

    Across six studies, this research found consistent evidence for motivated implicit theories about personality malleability: People perceive their weaknesses as more malleable than their strengths. Moreover, motivation also influences how people see themselves in the future, such that they expect their present strengths to remain constant, but they expect their present weaknesses to improve in the future. Several additional findings suggest the motivational nature of these effects: The difference in perceived malleability for strengths versus weaknesses was only observed for the self, not for other people. When the desirability of possessing a certain trait was manipulated, that trait was perceived to be more malleable when it was depicted as undesirable. And these different beliefs that people have about how malleable their traits are, and how they will develop in the future, were associated with their desire for change, which is higher for weaknesses versus strengths. © 2016 by the Society for Personality and Social Psychology, Inc.

  16. Novel boride base cermets with very high strength

    International Nuclear Information System (INIS)

    Ken-ichi Takagi; Mari Yonetsu; Yuji Yamasaki

    2001-01-01

    Mo 2 NiB 2 boride base cermets consist of a Mo 2 NiB 2 type complex boride as a hard phase and a Ni base binder. The addition of Cr and V to the cermets changed the boride structure from orthorhombic to tetragonal and resulted in the improvement of mechanical properties and microstructural refinement. The tetragonal Mo 2 NiB 2 was formed through the orthorhombic Mo 2 NiB 2 by the solid state reaction during sintering and not formed directly from the raw material powders. Ni-4.5B-46.9Mo-12.5V-xMn (wt.%) model cermets with five levels of Mn content from 0 to 10 wt.% were prepared to investigate the effects of Mn on the mechanical properties and microstructure Of Mo 2 NiB 2 base cermets. The transverse rupture strength (TRS) of the cermets depended strongly on the microstructure, which varied significantly with Mn content. The maximum TRS obtained at 2.5 wt.%Mn were 3.5 Gpa with hardness of 87 R A . (author)

  17. Computer-based theory of strategies

    Energy Technology Data Exchange (ETDEWEB)

    Findler, N V

    1983-01-01

    Some of the objectives and working tools of a new area of study, tentatively called theory of strategies, are described. It is based on the methodology of artificial intelligence, decision theory, operations research and digital gaming. The latter refers to computing activity that incorporates model building, simulation and learning programs in conflict situations. Three long-term projects which aim at automatically analyzing and synthesizing strategies are discussed. 27 references.

  18. Lateral strength force of URM structures based on a constitutive model for interface element

    Directory of Open Access Journals (Sweden)

    A.H. Akhaveissy

    Full Text Available This paper presents the numerical implementation of a new proposed interface model for modeling the behavior of mortar joints in masonry walls. Its theoretical framework is fully based on the plasticity theory. The Von Mises criterion is used to simulate the behavior of brick and stone units. The interface laws for contact elements are formulated to simulate the softening behavior of mortar joints under tensile stress; a normal linear cap model is also used to limit compressive stress. The numerical predictions based on the proposed model for the behavior of interface elements correlate very highly with test data. A new explicit formula based on results of proposed interface model is also presented to estimate the strength of unreinforced masonry structures. The closed form solution predicts the ultimate lateral load of unreinforced masonry walls less error percentage than ATC and FEMA-307. Consequently, the proposed closed form solution can be used satisfactorily to analyze unreinforced masonry structures.

  19. Grip Strength Survey Based on Hand Tool Usage

    Directory of Open Access Journals (Sweden)

    Erman ÇAKIT

    2016-12-01

    Full Text Available Hand grip strength is broadly used for performing tasks involving equipment in production and processing activities. Most professionals in this field rely on grip strength to perform their tasks. There were three main aims of this study: i determining various hand grip strength measurements for the group of hand tool users, ii investigating the effects of height, weight, age, hand dominance, body mass index, previous Cumulative Trauma Disorder (CTD diagnosis, and hand tool usage experience on hand grip strength, and iii comparing the obtained results with existing data for other populations. The study groups comprised 71 healthy male facility workers. The values of subjects’ ages was observed between 26 and 74 years. The data were statistically analyzed to assess the normality of data and the percentile values of grip strength. The results of this study demonstrate that there were no significance differences noted between dominant and non-dominant hands. However, there were highly significant differences between the CTD group and the other group. Hand grip strength for the dominant hand was positively correlated to height, weight, and body mass index, and negatively correlated to age and tool usage experience. Hand dominance, height, weight, body mass index, age and tool usage experience should be considered when establishing normal values for grip strength.

  20. Soil Moisture Retrieval Based on GPS Signal Strength Attenuation

    Directory of Open Access Journals (Sweden)

    Franziska Koch

    2016-07-01

    Full Text Available Soil moisture (SM is a highly relevant variable for agriculture, the emergence of floods and a key variable in the global energy and water cycle. In the last years, several satellite missions have been launched especially to derive large-scale products of the SM dynamics on the Earth. However, in situ validation data are often scarce. We developed a new method to retrieve SM of bare soil from measurements of low-cost GPS (Global Positioning System sensors that receive the freely available GPS L1-band signals. The experimental setup of three GPS sensors was installed at a bare soil field at the German Weather Service (DWD in Munich for almost 1.5 years. Two GPS antennas were installed within the soil column at a depth of 10 cm and one above the soil. SM was successfully retrieved based on GPS signal strength losses through the integral soil volume. The results show high agreement with measured and modelled SM validation data. Due to its non-destructive, cheap and low power setup, GPS sensor networks could also be used for potential applications in remote areas, aiming to serve as satellite validation data and to support the fields of agriculture, water supply, flood forecasting and climate change.

  1. A signal strength priority based position estimation for mobile platforms

    Science.gov (United States)

    Kalgikar, Bhargav; Akopian, David; Chen, Philip

    2010-01-01

    Global Positioning System (GPS) products help to navigate while driving, hiking, boating, and flying. GPS uses a combination of orbiting satellites to determine position coordinates. This works great in most outdoor areas, but the satellite signals are not strong enough to penetrate inside most indoor environments. As a result, a new strain of indoor positioning technologies that make use of 802.11 wireless LANs (WLAN) is beginning to appear on the market. In WLAN positioning the system either monitors propagation delays between wireless access points and wireless device users to apply trilateration techniques or it maintains the database of location-specific signal fingerprints which is used to identify the most likely match of incoming signal data with those preliminary surveyed and saved in the database. In this paper we investigate the issue of deploying WLAN positioning software on mobile platforms with typically limited computational resources. We suggest a novel received signal strength rank order based location estimation system to reduce computational loads with a robust performance. The proposed system performance is compared to conventional approaches.

  2. Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance.

    Science.gov (United States)

    Wirth, Klaus; Keiner, Michael; Hartmann, Hagen; Sander, Andre; Mickel, Christoph

    2016-12-01

    The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg) joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development) were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance.

  3. Flexural properties and impact strength of denture base resins reinforced with micronized glass flakes

    Directory of Open Access Journals (Sweden)

    Ronak H Choksi

    2016-01-01

    Conclusion: Flexural strength of unmodified PMMA denture base resin decreases with increase in the concentration of glass flakes. Impact strength does not show any significant change at 5% concentration of glass flakes and impact strength significantly reduces with the addition of glass flakes in 10% and 20%.

  4. A Performance-Based Instructional Theory

    Science.gov (United States)

    Lawson, Tom E.

    1974-01-01

    The rationale for a performanced- based instructional theory has arisen from significant advances during the past several years in instructional psychology. Four major areas of concern are: analysis of subject-matter content in terms of performance competencies, diagnosis of pre-instructional behavior, formulation of an instructional…

  5. Jigsaw Cooperative Learning: Acid-Base Theories

    Science.gov (United States)

    Tarhan, Leman; Sesen, Burcin Acar

    2012-01-01

    This study focused on investigating the effectiveness of jigsaw cooperative learning instruction on first-year undergraduates' understanding of acid-base theories. Undergraduates' opinions about jigsaw cooperative learning instruction were also investigated. The participants of this study were 38 first-year undergraduates in chemistry education…

  6. Principles of strengths-based nursing leadership for strengths-based nursing care: a new paradigm for nursing and healthcare for the 21st century.

    Science.gov (United States)

    Gottlieb, Laurie N; Gottlieb, Bruce; Shamian, Judith

    2012-06-01

    The current healthcare system is slowly evolving into a new system built on a vision of health promotion, primary care and community-based home care, with hospitals still being a core pillar of the healthcare system but not its primary service. This transformation requires a new approach to practice, namely, Strengths-Based Nursing Care (SBC). SBC is about mobilizing, capitalizing and developing a person's strengths to promote health and facilitate healing. For nurses to practise SBNC requires strong nursing leadership that creates conditions to enable them to do so. Strengths-Based Nursing Leadership complements and acts in synergy with, SBNC. This paper describes eight principles of Strengths-Based Nursing Leadership to support SBNC.

  7. Microstructure and bonding strength of Ni-based alloy coating

    Directory of Open Access Journals (Sweden)

    LIU Qing

    2006-05-01

    Full Text Available A Ni-Cr-B-Si coating technique was developed and successfully applied on austenite grey iron substrate in a conventional resistance furnace under graphite powder protection. The microstructure, phase distribution, chemical composition profile and microhardness along the coating layer depth were investigated. Shear strength of the coating was also tested. Microanalysis shows that the coating is consist of γ-Ni solution and γ-Ni+Ni3B lamellar eutectic, as well as small amount of Cr5B3 particles. Diffusion induced metallurgical bonding occurs at the coating/substrate interfaces, and the higher the temperature, the more sufficient elements diffused, the broader interfusion region and the larger bonding strength, but it has an optimum value. And the bonding strength at the interface can be enable to reach 250-270 MPa, which is nearly the same as that of processed by flame spray. The microhardness along the coating layer depth shows a gradient distribution manner.

  8. Estimation of distance error by fuzzy set theory required for strength determination of HDR (192)Ir brachytherapy sources.

    Science.gov (United States)

    Kumar, Sudhir; Datta, D; Sharma, S D; Chourasiya, G; Babu, D A R; Sharma, D N

    2014-04-01

    Verification of the strength of high dose rate (HDR) (192)Ir brachytherapy sources on receipt from the vendor is an important component of institutional quality assurance program. Either reference air-kerma rate (RAKR) or air-kerma strength (AKS) is the recommended quantity to specify the strength of gamma-emitting brachytherapy sources. The use of Farmer-type cylindrical ionization chamber of sensitive volume 0.6 cm(3) is one of the recommended methods for measuring RAKR of HDR (192)Ir brachytherapy sources. While using the cylindrical chamber method, it is required to determine the positioning error of the ionization chamber with respect to the source which is called the distance error. An attempt has been made to apply the fuzzy set theory to estimate the subjective uncertainty associated with the distance error. A simplified approach of applying this fuzzy set theory has been proposed in the quantification of uncertainty associated with the distance error. In order to express the uncertainty in the framework of fuzzy sets, the uncertainty index was estimated and was found to be within 2.5%, which further indicates that the possibility of error in measuring such distance may be of this order. It is observed that the relative distance li estimated by analytical method and fuzzy set theoretic approach are consistent with each other. The crisp values of li estimated using analytical method lie within the bounds computed using fuzzy set theory. This indicates that li values estimated using analytical methods are within 2.5% uncertainty. This value of uncertainty in distance measurement should be incorporated in the uncertainty budget, while estimating the expanded uncertainty in HDR (192)Ir source strength measurement.

  9. Effect of 8 weeks of free-weight and machine-based strength training on strength and power performance

    Directory of Open Access Journals (Sweden)

    Wirth Klaus

    2016-12-01

    Full Text Available The aim of this study was to evaluate the effectiveness of free-weight and machine-based exercises to increase different strength and speed-strength variables. One hundred twenty male participants (age: 23.8 ± 2.5 years; body height: 181.0 ± 6.8 cm; body mass: 80.2 ± 8.9 kg joined the study. The 2 experimental groups completed an 8 week periodized strength training program that included 2 training sessions per week. The exercises that were used in the strength training programs were the parallel barbell squat and the leg press. Before and after the training period, the 1-repetition-maximum in the barbell squat and the leg press, the squat jump, the countermovement jump and unilateral isometric force (maximal isometric force and the rate of force development were evaluated. To compare each group pre vs. post-intervention, analysis of variance with repeated measures and Scheffé post-hoc tests were used. The leg press group increased their 1-repetition-maximum significantly (p < 0.001, while in the squat group such variables as 1-repetition-maximum, the squat jump and the countermovement jump increased significantly (p < 0.001. The maximal isometric force showed no statistically significant result for the repeated measures factor, while the rate of force development of the squat group even showed a statistically significant decrease. Differences between the 2 experimental groups were detected for the squat jump and the countermovement jump. In comparison with the leg press, the squat might be a better strength training exercise for the development of jump performance.

  10. Controller Design of Complex System Based on Nonlinear Strength

    Directory of Open Access Journals (Sweden)

    Rongjun Mu

    2015-01-01

    Full Text Available This paper presents a new idea of controller design for complex systems. The nonlinearity index method was first developed for error propagation of nonlinear system. The nonlinearity indices access the boundary between the strong and the weak nonlinearities of the system model. The algorithm of nonlinearity index according to engineering application is first proposed in this paper. Applying this method on nonlinear systems is an effective way to measure the nonlinear strength of dynamics model over the full flight envelope. The nonlinearity indices access the boundary between the strong and the weak nonlinearities of system model. According to the different nonlinear strength of dynamical model, the control system is designed. The simulation time of dynamical complex system is selected by the maximum value of dynamic nonlinearity indices. Take a missile as example; dynamical system and control characteristic of missile are simulated. The simulation results show that the method is correct and appropriate.

  11. Exercise habit strength, planning and the theory of planned behaviour: an action control approach

    NARCIS (Netherlands)

    de Bruijn, G.-J.

    2011-01-01

    Objectives Action control refers to the successful translation of intention into behaviour. The purpose of this study was to explore the potential usefulness of extending intention-exercise profiles with past exercise behaviour and exercise habit strength and the potential discriminative effect of

  12. Interpretation of bend strength increase of graphite by the couple-stress theory

    International Nuclear Information System (INIS)

    Tang, P.Y.

    1981-05-01

    This paper presents a continued evaluation of the applicability of the couple-stress constitutive theory to graphite. The evaluation is performed by examining four-point bend and uniaxial tensile data of various sized cylindrical and square specimens for three grades of graphites. These data are superficially inconsistent and, usually, at variance with the predictions of classical theories. Nevertheless, this evaluation finds that they can be consistently interpreted by the couple-stress theory. This is compatible with results of an initial evaluation that considered one size of cylindrical specimen for H-451 graphite

  13. Theory-based explanation as intervention.

    Science.gov (United States)

    Weisman, Kara; Markman, Ellen M

    2017-10-01

    Cogent explanations are an indispensable means of providing new information and an essential component of effective education. Beyond this, we argue that there is tremendous untapped potential in using explanations to motivate behavior change. In this article we focus on health interventions. We review four case studies that used carefully tailored explanations to address gaps and misconceptions in people's intuitive theories, providing participants with a conceptual framework for understanding how and why some recommended behavior is an effective way of achieving a health goal. These case studies targeted a variety of health-promoting behaviors: (1) children washing their hands to prevent viral epidemics; (2) parents vaccinating their children to stem the resurgence of infectious diseases; (3) adults completing the full course of an antibiotic prescription to reduce antibiotic resistance; and (4) children eating a variety of healthy foods to improve unhealthy diets. Simply telling people to engage in these behaviors has been largely ineffective-if anything, concern about these issues is mounting. But in each case, teaching participants coherent explanatory frameworks for understanding health recommendations has shown great promise, with such theory-based explanations outperforming state-of-the-art interventions from national health authorities. We contrast theory-based explanations both with simply listing facts, information, and advice and with providing a full-blown educational curriculum, and argue for providing the minimum amount of information required to understand the causal link between a target behavior and a health outcome. We argue that such theory-based explanations lend people the motivation and confidence to act on their new understanding.

  14. Ground reaction curve based upon block theory

    International Nuclear Information System (INIS)

    Yow, J.L. Jr.; Goodman, R.E.

    1985-09-01

    Discontinuities in a rock mass can intersect an excavation surface to form discrete blocks (keyblocks) which can be unstable. Once a potentially unstable block is identified, the forces affecting it can be calculated to assess its stability. The normal and shear stresses on each block face before displacement are calculated using elastic theory and are modified in a nonlinear way by discontinuity deformations as the keyblock displaces. The stresses are summed into resultant forces to evaluate block stability. Since the resultant forces change with displacement, successive increments of block movement are examined to see whether the block ultimately becomes stable or fails. Two-dimensional (2D) and three-dimensional (3D) analytic models for the stability of simple pyramidal keyblocks were evaluated. Calculated stability is greater for 3D analyses than for 2D analyses. Calculated keyblock stability increases with larger in situ stress magnitudes, larger lateral stress ratios, and larger shear strengths. Discontinuity stiffness controls blocks displacement more strongly than it does stability itself. Large keyblocks are less stable than small ones, and stability increases as blocks become more slender

  15. The Use of Mapping in Child Welfare Investigations: A Strength-Based Hybrid Intervention

    Science.gov (United States)

    Lwin, Kristen; Versanov, Avi; Cheung, Connie; Goodman, Deborah; Andrews, Nancy

    2014-01-01

    To enhance strengths-based service, a large urban child welfare agency in Ontario, Canada implemented part of the Signs of Safety (SOS) model in 2010. SOS was created to engage families involved with the child welfare system, and is rooted in the beliefs of collaboration, strengths-based practice, and safety. The hybrid of the full SOS model…

  16. Assessment of oscillator strengths with multiconfigurational short-range density functional theory for electronic excitations in organic molecules

    DEFF Research Database (Denmark)

    Hedegård, Erik Donovan

    2017-01-01

    considered the large collection of organic molecules whose excited states were investigated with a range of electronic structure methods by Thiel et al. As a by-product of our calculations of oscillator strengths, we also obtain electronic excitation energies, which enable us to compare the performance......We have in a series of recent papers investigated electronic excited states with a hybrid between a complete active space self-consistent field (CASSCF) wave function and density functional theory (DFT). This method has been dubbed the CAS short-range DFT method (CAS–srDFT). The previous papers...

  17. Single nuclear transfer strengths and sum rules in the interacting boson-fermion model and in the spectral averaging theory

    International Nuclear Information System (INIS)

    Kota, V.K.B.

    1991-01-01

    In the interacting boson-fermion model of collective nuclei, in the symmetry limits of the model appropriate for vibrational, rotational and γ-unstable nuclei, for one-particle transfer, the selection rules, model predictions for the allowed strengths and comparison of theory with experiment are briefly reviewed. In the spectral-averaging theory, with the specific example of orbit occupancies, the smoothed forms (linear or better ratio of Gaussians) as determined by central limit theorems, how they provide a good criterion for selecting effective interactions and the convolution structure of occupancy densities in huge spaces are described. Complementary information provided by nuclear models and statistical laws is broughtout. (author). 63 refs., 5 figs

  18. Training in Strength-Based Intervention and Assessment Methodologies in APA-Accredited Psychology Programs

    Science.gov (United States)

    Nichols, Kayla; Graves, Scott L., Jr.

    2018-01-01

    The importance of identifying and building on individual strengths has been a key component of many psychoeducational theories and modalities focused on developing interventions. However, program training in this growing area is not well known. As such, this is the first study designed to ascertain the American Psychological Association-accredited…

  19. The intersection of software and strengths: Using internet technology and case management software to assist Strength-Based Practice.

    Science.gov (United States)

    Clark, Michael D; Brien, Dale W

    2016-01-01

    The focus of this investigation is the helping professionals working within American Indian and Alaska Native (AI/AN) communities. This article looks at how innovative technology-in the form of automated case management software and Internet connectivity-can assist effective implementation of Strength-based Practice and agency services within tribal courts and the many other helping agencies that serve AI/AN populations. We seek to expand practice knowledge by reviewing the benefits that this software and Internet connectivity can offer to agency operations and exploring how they can assist case management services.

  20. Information theory based approaches to cellular signaling.

    Science.gov (United States)

    Waltermann, Christian; Klipp, Edda

    2011-10-01

    Cells interact with their environment and they have to react adequately to internal and external changes such changes in nutrient composition, physical properties like temperature or osmolarity and other stresses. More specifically, they must be able to evaluate whether the external change is significant or just in the range of noise. Based on multiple external parameters they have to compute an optimal response. Cellular signaling pathways are considered as the major means of information perception and transmission in cells. Here, we review different attempts to quantify information processing on the level of individual cells. We refer to Shannon entropy, mutual information, and informal measures of signaling pathway cross-talk and specificity. Information theory in systems biology has been successfully applied to identification of optimal pathway structures, mutual information and entropy as system response in sensitivity analysis, and quantification of input and output information. While the study of information transmission within the framework of information theory in technical systems is an advanced field with high impact in engineering and telecommunication, its application to biological objects and processes is still restricted to specific fields such as neuroscience, structural and molecular biology. However, in systems biology dealing with a holistic understanding of biochemical systems and cellular signaling only recently a number of examples for the application of information theory have emerged. This article is part of a Special Issue entitled Systems Biology of Microorganisms. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Theory-based interventions for contraception.

    Science.gov (United States)

    Lopez, Laureen M; Grey, Thomas W; Chen, Mario; Tolley, Elizabeth E; Stockton, Laurie L

    2016-11-23

    The explicit use of theory in research helps expand the knowledge base. Theories and models have been used extensively in HIV-prevention research and in interventions for preventing sexually transmitted infections (STIs). The health behavior field uses many theories or models of change. However, many educational interventions addressing contraception have no explicit theoretical base. To review randomized controlled trials (RCTs) that tested a theoretical approach to inform contraceptive choice and encourage or improve contraceptive use. To 1 November 2016, we searched for trials that tested a theory-based intervention for improving contraceptive use in PubMed, CENTRAL, POPLINE, Web of Science, ClinicalTrials.gov, and ICTRP. For the initial review, we wrote to investigators to find other trials. Included trials tested a theory-based intervention for improving contraceptive use. Interventions addressed the use of one or more methods for contraception. The reports provided evidence that the intervention was based on a specific theory or model. The primary outcomes were pregnancy and contraceptive choice or use. We assessed titles and abstracts identified during the searches. One author extracted and entered the data into Review Manager; a second author verified accuracy. We examined studies for methodological quality.For unadjusted dichotomous outcomes, we calculated the Mantel-Haenszel odds ratio (OR) with 95% confidence interval (CI). Cluster randomized trials used various methods of accounting for the clustering, such as multilevel modeling. Most reports did not provide information to calculate the effective sample size. Therefore, we presented the results as reported by the investigators. We did not conduct meta-analysis due to varied interventions and outcome measures. We included 10 new trials for a total of 25. Five were conducted outside the USA. Fifteen randomly assigned individuals and 10 randomized clusters. This section focuses on nine trials with high or

  2. A Technology Based Program That Matches Enrichment Resources With Student Strengths

    Directory of Open Access Journals (Sweden)

    J.S. Renzulli

    2007-09-01

    Full Text Available Remarkable advances in instructionalcommunication technology (ICT have now made ispossible to provide high levels of enrichment and thekinds of curricular differentiation that facilitateadvanced learning services to students who have accessto a computer and the Internet. But in order tomaximize the potential if ICT it is necessary to constructprograms that are based on learning theory that goesbeyond the didactic and prescriptive models that haveresulted in too much worksheets-on-line and electronicencyclopedias. The Renzulli Learning System (RLSuses a strength-based learning theory called theEnrichment Triad Model that is purposefully designedto promote advanced level learning, creativeproductivity, and high levels of student engagement byfocusing on the application of knowledge rather than themere acquisition and storage of information.The Renzulli Learning System is acomprehensive program that begins by providing acomputer-generated profile of each student’s academicstrengths, interests, learning styles, and preferred modesof expression. A search engine then matches Internetresources to the student’s profile from fourteen carefullyscreened data bases that are categorized by subject area,grade level, state curricular standards, and degree ofcomplexity. There are also hundreds of enrichmentactivities that can be down loaded and reproduced forindividual or group learning activities. A managementsystem called the Wizard Project Maker guides studentsin the application of knowledge to teacher or studentselected assignments, independent research studies, orcreative projects that individuals or small groups wouldlike to pursue. Students and teachers can evaluate thequality of students’ products using a rubric called TheStudent Product Assessment Form. Students can rateeach site visited, conduct a self-assessment of what theyhave gained from the site, and place resources in theirown Total talent Portfolio for future use. RLS alsoincludes a

  3. Comparison of Flexural Strength of Different CAD/CAM PMMA-Based Polymers.

    Science.gov (United States)

    Alp, Gülce; Murat, Sema; Yilmaz, Burak

    2018-01-28

    To compare the flexural strength of different computer-aided design/computer-aided manufacturing (CAD/CAM) poly(methyl methacrylate)-based (PMMA) polymers and conventional interim resin materials after thermocycling. Rectangular-shaped specimens (n = 15, for each material) (25 × 2 × 2 mm 3 ) were fabricated from 3 CAD/CAM PMMA-based polymers (Telio CAD [T]; M-PM-Disc [M]; Polident-PMMA [P]), 1 bis-acrylate composite resin (Protemp 4 [PT]), and 1 conventional PMMA (ArtConcept Artegral Dentine [C]) according to ISO 10477:2004 Standards (Dentistry-Polymer-Based Crown and Bridge Materials). The specimens were subjected to 10,000 thermocycles (5 to 55°C). Three-point flexural strength of the specimens was tested in a universal testing machine at a 1.0 mm/min crosshead speed, and the flexural strength data (σ) were calculated (MPa). The flexural strength values were statistically analyzed using 1-way ANOVA, and Tukey HSD post-hoc test for multiple comparisons (α = 0.05). Flexural strength values ranged between 66.1 ± 13.1 and 131.9 ± 19.8 MPa. There were significant differences among the flexural strengths of tested materials, except for between T and P CAD/CAM PMMA-based polymers (p > 0.05). CAD/CAM PMMA-based polymer M had the highest flexural strength and conventional PMMA had the lowest (p CAD/CAM PMMA-based T and P polymers had significantly higher flexural strength than the bis-acrylate composite resin (p CAD/CAM PMMA-based M (p CAD/CAM PMMA-based polymers was greater than the flexural strength of bis-acrylate composite resin, which had a greater flexural strength compared to conventional PMMA resin. © 2018 by the American College of Prosthodontists.

  4. Testing the Strength of the Iron Cage: A Meta-Analysis of Neo-Institutional Theory

    NARCIS (Netherlands)

    P.P.M.A.R. Heugens (Pursey); M.W. Lander (Michel)

    2007-01-01

    textabstractIn this study, we use meta-analytical techniques to quantitatively synthesize and evaluate the sizeable body of empirical work that has been conducted under the banner of neo-institutional theory. We find strong support for the influence of mimetic pressures on organizational

  5. Introduction to the theory of bases

    CERN Document Server

    Marti, Jürg T

    1969-01-01

    Since the publication of Banach's treatise on the theory of linear operators, the literature on the theory of bases in topological vector spaces has grown enormously. Much of this literature has for its origin a question raised in Banach's book, the question whether every sepa­ rable Banach space possesses a basis or not. The notion of a basis employed here is a generalization of that of a Hamel basis for a finite dimensional vector space. For a vector space X of infinite dimension, the concept of a basis is closely related to the convergence of the series which uniquely correspond to each point of X. Thus there are different types of bases for X, according to the topology imposed on X and the chosen type of convergence for the series. Although almost four decades have elapsed since Banach's query, the conjectured existence of a basis for every separable Banach space is not yet proved. On the other hand, no counter examples have been found to show the existence of a special Banach space having no basis. Howe...

  6. Platoon Dispersion Analysis Based on Diffusion Theory

    Directory of Open Access Journals (Sweden)

    Badhrudeen Mohamed

    2017-01-01

    Full Text Available Urbanization and gro wing demand for travel, causes the traffic system to work ineffectively in most urban areas leadin g to traffic congestion. Many approaches have been adopted to address this problem, one among them being the signal co-ordination. This can be achieved if the platoon of vehicles that gets discharged at one signal gets green at consecutive signals with minimal delay. However, platoons tend to get dispersed as they travel and this dispersion phenomenon should be taken into account for effective signal coordination. Reported studies in this area are from the homogeneous and lane disciplined traffic conditions. This paper analyse the platoon dispersion characteristics under heterogeneous and lane-less traffic conditions. Out of the various modeling techniques reported, the approach based on diffusion theory is used in this study. The diffusion theory based models so far assumed thedata to follow normal distribution. However, in the present study, the data was found to follow lognormal distribution and hence the implementation was carried out using lognormal distribution. The parameters of lognormal distribution were calibrated for the study condition. For comparison purpose, normal distribution was also calibrated and the results were evaluated. It was foun d that model with log normal distribution performed better in all cases than the o ne with normal distribution.

  7. Advances in heuristically based generalized perturbation theory

    International Nuclear Information System (INIS)

    Gandini, A.

    1994-01-01

    A distinctive feature of heuristically based generalized perturbation theory methodology consists in the systematic use of importance conservation concepts. As well known, this use leads to fundamental reciprocity relationship. Instead, the alternative variational and differential one approaches make a consistent use of the properties and adjoint functions. The equivalence between the importance and the adjoint functions have been demonstrated in important cases. There are some instances, however, in which the commonly known operator governing the adjoint function are not adequate. In this paper ways proposed to generalize this rules, as adopted with the heuristic generalized perturbation theory methodology, are illustrated. When applied to the neutron/nuclide field characterizing the core evolution in a power reactor system, in which also an intensive control variable (ρ) is defined, these rules leas to an orthogonality relationship connected to this same control variable. A set of ρ-mode eigenfunctions may be correspondingly defined and an extended concept of reactivity (generalizing that commonly associated with the multiplication factor) proposed as more directly indicative of the controllability of a critical reactor system. (author). 25 refs

  8. System Dynamics as Model-Based Theory Building

    OpenAIRE

    Schwaninger, Markus; Grösser, Stefan N.

    2008-01-01

    This paper introduces model-based theory building as a feature of system dynamics (SD) with large potential. It presents a systemic approach to actualizing that potential, thereby opening up a new perspective on theory building in the social sciences. The question addressed is if and how SD enables the construction of high-quality theories. This contribution is based on field experiment type projects which have been focused on model-based theory building, specifically the construction of a mi...

  9. Robustness and discriminatory strength of citation-based journal indicators

    DEFF Research Database (Denmark)

    Andersen, Jens Peter; Christensen, Anette Luther

    AIM: A plethora of journal indicators exists, and are used e.g. in national assessment exercises as part of the basis for university funding. Recent studies report as many as 39 indicators of which the major part are citation based. While studies have shown these citation-based journal indicators...

  10. 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.

  11. Plasma balance equations based on orbit theory

    International Nuclear Information System (INIS)

    Lehnert, B.

    1982-01-01

    A set of plasma balance equations is proposed which is based on orbit theory and the particle distribution function, to provide means for theoretical analysis of a number of finite Larmor radius (FLR) phenomena without use of the Vlasov equation. Several important FLR effects originate from the inhomogeneity of an electric field in the plasma. The exact solution of a simple case shows that this inhomogeneity introduces fundamental changes in the physics of the particle motion. Thus, the periodic Larmor motion (gyration) is shifted in frequency and becomes elliptically polarized. Further, the non-periodic guiding-centre drift obtains additional components, part of which are accelerated such as to make the drift orbits intersect the equipotential surfaces of a static electric field. An attempt is finally made to classify the FLR effects, also with the purpose of identifying phenomena which have so far not been investigated. (author)

  12. Mixture proportioning of fly ash-concretes based on mortar strength and flow data

    International Nuclear Information System (INIS)

    Nusrat, A.; Tahir, M.A.

    2008-01-01

    A method of mixture proportioning of fly ash concretes is presented. The method is based on the strength and flow data of a minimum of nine fly ash-cement mortars. The essence of the method is that three fly ash-binder ratios are to be combined with three water-binder ratios in the range of interest. The strength and water demand data are analyzed for constructing mixture proportion charts. The strength vs. water-binder ratio charts are prepared by down-scaling the 50-mm mortar strength to the 150-mm standard concrete cylinders. The method is illustrated with the help of examples. The trial mixtures proportioned using the proposed methods have reasonably achieved the 28 day target strengths. (author)

  13. Adhesion strength study of IBAD-MOCVD-based 2G HTS wire using a peel test

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: yzhang@superpower-inc.com [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Hazelton, D.W.; Knoll, A.R.; Duval, J.M.; Brownsey, P.; Repnoy, S.; Soloveichik, S.; Sundaram, A.; McClure, R.B. [SuperPower Inc., 450 Duane Avenue, Schenectady, NY 12304 (United States); Majkic, G.; Selvamanickam, V. [University of Houston, 4800 Calhoun Road, Houston, TX 77204 (United States)

    2012-02-15

    A peel test was used to study the adhesion strength of a commercial grade 2G HTS wire which features a characteristic multilayer structure with the rare earth-based MOCVD superconducting film deposited on an IBAD-MgO template. The peel test could be carried out at various peeling angles (from 90 Degree-Sign to 180 Degree-Sign) and the peel strength of a wire was defined as the steady-state peeling load determined from a load-displacement curve. The test results had good reproducibility and accuracy, making the test a reliable and useful method for studying the adhesion strength of the wire. By characterizing the peeled surfaces the weakest interface in a wire could be identified. The peel strength data of the wire was analyzed together with the performance of the experimental magnet coils fabricated using the wire. The effect of the silver contact layer annealing on the peel strength is discussed.

  14. Adhesion strength study of IBAD-MOCVD-based 2G HTS wire using a peel test

    International Nuclear Information System (INIS)

    Zhang, Y.; Hazelton, D.W.; Knoll, A.R.; Duval, J.M.; Brownsey, P.; Repnoy, S.; Soloveichik, S.; Sundaram, A.; McClure, R.B.; Majkic, G.; Selvamanickam, V.

    2012-01-01

    A peel test was used to study the adhesion strength of a commercial grade 2G HTS wire which features a characteristic multilayer structure with the rare earth-based MOCVD superconducting film deposited on an IBAD-MgO template. The peel test could be carried out at various peeling angles (from 90° to 180°) and the peel strength of a wire was defined as the steady-state peeling load determined from a load-displacement curve. The test results had good reproducibility and accuracy, making the test a reliable and useful method for studying the adhesion strength of the wire. By characterizing the peeled surfaces the weakest interface in a wire could be identified. The peel strength data of the wire was analyzed together with the performance of the experimental magnet coils fabricated using the wire. The effect of the silver contact layer annealing on the peel strength is discussed.

  15. Development and application of high strength ternary boride base cermets

    International Nuclear Information System (INIS)

    Takagi, Ken-ichi

    2006-01-01

    Reaction boronizing sintering is a novel strategy to form a ternary boride coexisting with a metal matrix in a cermet during liquid phase sintering. This new sintering technique has successfully developed world first ternary boride base cermets with excellent mechanical properties such as Mo 2 FeB 2 , Mo 2 NiB 2 and WCoB base ones. In these cermets Mo 2 FeB 2 and Mo 2 NiB 2 base ones consist of a tetragonal M 3 B 2 (M: metal)-type complex boride as a hard phase and a transition metal base matrix. The cermets have already been applied to wear resistant applications such as injection molding machine parts, can making tools, and hot copper extruding dies, etc. This paper focuses on the characteristics, effects of the additional elements on the mechanical properties and structure, and practical applications of the ternary boride base cermets. - Graphical abstract: TRS and hardness of Ni-5B-51Mo-17.5Cr and Ni-5B-51Mo-12.5Cr-5V-xMn mass% cermets as functions of Mn content (Fig. 17)

  16. A Renewed Focus on Strengths-Based Assessment in Schools

    Science.gov (United States)

    Climie, Emma; Henley, Laura

    2016-01-01

    School-based practitioners are often called upon to provide assessment and recommendations for struggling students. These assessments often open doors to specialised services or interventions and provide opportunities for students to build competencies in areas of need. However, these assessments often fail to highlight the abilities of these…

  17. A simple nanoindentation-based methodology to assess the strength of brittle thin films

    International Nuclear Information System (INIS)

    Borrero-Lopez, Oscar; Hoffman, Mark; Bendavid, Avi; Martin, Phil J.

    2008-01-01

    In this work, we report a simple methodology to assess the mechanical strength of sub-micron brittle films. Nanoindentation of as-deposited tetrahedral amorphous carbon (ta-C) and Ti-Si-N nanocomposite films on silicon substrates followed by cross-sectional examination of the damage with a focused ion beam (FIB) miller allows the occurrence of cracking to be assessed in comparison with discontinuities (pop-ins) in the load-displacement curves. Strength is determined from the critical loads at which first cracking occurs using the theory of plates on a soft foundation. This methodology enables Weibull plots to be readily obtained, avoiding complex freestanding-film machining processes. This is of great relevance, since the mechanical strength of thin films ultimately controls their reliable use in a broad range of functional uses such as tribological coatings, magnetic drives, MEMS and biomedical applications

  18. Fatigue Strength Estimation Based on Local Mechanical Properties for Aluminum Alloy FSW Joints

    Directory of Open Access Journals (Sweden)

    Kittima Sillapasa

    2017-02-01

    Full Text Available Overall fatigue strengths and hardness distributions of the aluminum alloy similar and dissimilar friction stir welding (FSW joints were determined. The local fatigue strengths as well as local tensile strengths were also obtained by using small round bar specimens extracted from specific locations, such as the stir zone, heat affected zone, and base metal. It was found from the results that fatigue fracture of the FSW joint plate specimen occurred at the location of the lowest local fatigue strength as well as the lowest hardness, regardless of microstructural evolution. To estimate the fatigue strengths of aluminum alloy FSW joints from the hardness measurements, the relationship between fatigue strength and hardness for aluminum alloys was investigated based on the present experimental results and the available wide range of data from the references. It was found as: σa (R = −1 = 1.68 HV (σa is in MPa and HV has no unit. It was also confirmed that the estimated fatigue strengths were in good agreement with the experimental results for aluminum alloy FSW joints.

  19. Strength and gas-abrasive wear-resistance of zirconium carbide based cerments

    International Nuclear Information System (INIS)

    Samsonov, G.V.; Dan'kin, A.A.; Markov, A.A.; Bogomol, I.V.

    1976-01-01

    Results relating to a study of cermet strength and wear resistance by means of a gas-abrasive flow are presented. It has been found that with a higher amount of the metallic binder (over 25 at.%) in zirconium carbide-based cermets the bending and compression strength and also hardness and wear resistance within the systems ZrC-Nb, ZrC-Mo, ZrC-W become lower. The interrelation of the cermet wear resistance of the various systems and their bending and compression strengths, which, in turn, depend on the electronic structure is shown

  20. Assessment of the impact strength of the denture base resin polymerized by various processing techniques

    Directory of Open Access Journals (Sweden)

    Rajashree Jadhav

    2013-01-01

    Full Text Available Aim : To measure the impact strength of denture base resins polymerized using short and long curing cycles by water bath, pressure cooker and microwave techniques. Materials and Methods: For impact strength testing, 60 samples were made. The sample dimensions were 60 mm × 12 mm × 3 mm, as standardized by the American Standards for Testing and Materials (ASTM. A digital caliper was used to locate the midpoint of sample. The impact strength was measured in IZOD type of impact tester using CEAST Impact tester. The pendulum struck the sample and it broke. The energy required to break the sample was measured in Joules. Data were analyzed using Student′s " t" test. Results: There was statistically significant difference in the impact strength of denture base resins polymerized by long curing cycle and short curing cycle in each technique, with the long curing processing being the best. Conclusion: The polymerization technique plays an important role in the influence of impact strength in the denture base resin. This research demonstrates that the denture base resin polymerized by microwave processing technique possessed the highest impact strength.

  1. Modeling acquaintance networks based on balance theory

    Directory of Open Access Journals (Sweden)

    Vukašinović Vida

    2014-09-01

    Full Text Available An acquaintance network is a social structure made up of a set of actors and the ties between them. These ties change dynamically as a consequence of incessant interactions between the actors. In this paper we introduce a social network model called the Interaction-Based (IB model that involves well-known sociological principles. The connections between the actors and the strength of the connections are influenced by the continuous positive and negative interactions between the actors and, vice versa, the future interactions are more likely to happen between the actors that are connected with stronger ties. The model is also inspired by the social behavior of animal species, particularly that of ants in their colony. A model evaluation showed that the IB model turned out to be sparse. The model has a small diameter and an average path length that grows in proportion to the logarithm of the number of vertices. The clustering coefficient is relatively high, and its value stabilizes in larger networks. The degree distributions are slightly right-skewed. In the mature phase of the IB model, i.e., when the number of edges does not change significantly, most of the network properties do not change significantly either. The IB model was found to be the best of all the compared models in simulating the e-mail URV (University Rovira i Virgili of Tarragona network because the properties of the IB model more closely matched those of the e-mail URV network than the other models

  2. Comparison of polymer-based temporary crown and fixed partial denture materials by diametral tensile strength.

    Science.gov (United States)

    Ha, Seung-Ryong; Yang, Jae-Ho; Lee, Jai-Bong; Han, Jung-Suk; Kim, Sung-Hun

    2010-03-01

    The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (ø 4 mm × 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (α = 0.05). Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.

  3. Strengths and Limitations of Evidence-Based Dermatology

    Science.gov (United States)

    Williams, Hywel C

    2014-01-01

    The need for understanding and reflecting on evidence-based dermatology (EBD) has never been greater given the exponential growth of new external evidence to inform clinical practice. Like any other branch of medicine, dermatologists need to acquire new skills in constructing answerable questions, efficiently searching electronic bibliographic databases, and critically appraising different types of studies. Secondary summaries of evidence in the form of systematic reviews (SR), that is, reviews that are conducted in a systematic, unbiased and explicit manner, reside at the top of the evidence hierarchy, because they are less prone to bias than traditional expert reviews. In addition to providing summaries of the best external evidence, systematic reviews and randomized controlled trials (RCTs) are also powerful ways of identifying research gaps and ultimately setting the agenda of future clinical research in dermatology. But like any paradigm, EBD can have its limitations. Wrong application, misuse and overuse of EBD can have serious consequences. For example, mindless pooling together of data from dissimilar studies in a meta-analysis may render it a form of reductionism that does not make any sense. Similarly, even highly protocolised study designs such as SRs and RCTs are still susceptible to some degree of dishonesty and bias. Over-reliance on randomized controlled trials (RCT) may be inappropriate, as RCTs are not a good source for picking up rare but important adverse effects such as lupus syndrome with minocycline. A common criticism leveled against SRs is that these frequently conclude that there is lack of sufficient evidence to inform current clinical practice, but arguably, such a perception is grounded more on the interpretation of the SRs than anything else. The apparent absence of evidence should not paralyze the dermatologist to adopt a state of therapeutic nihilism. Poor primary data and an SR based on evidence that is not up-to-date are also

  4. Yield strengths of tungsten-base composites determined from bend tests

    International Nuclear Information System (INIS)

    Zukas, E.G.; Eash, D.T.

    1976-08-01

    The variation in yield strength with either strain rate or temperature was determined for a number of tungsten-base composites by use of the simple three-point bend test. The yield strengths were comparable with those obtained in standard tensile tests. Additional studies on 1019 steel, either in the as-rolled or annealed condition, gave results in agreement with handbook values, as did two aluminum alloys. These results demonstrate that the bend test deserves wider acceptance in materials testing programs

  5. Enacting Firm, Fair and Friendly Practice: A Model for Strengths-Based Child Protection Relationships?

    Science.gov (United States)

    Oliver, Carolyn; Charles, Grant

    2016-06-01

    Strengths-based solution-focused approaches are gaining ground in statutory child protection work, but few studies have asked front line practitioners how they navigate the complex worker-client relationships such approaches require. This paper describes one component of a mixed-methods study in a large Canadian statutory child protection agency in which 225 workers described how they applied the ideas of strengths-based practice in their daily work. Interviews with twenty-four practitioners were analysed using an interpretive description approach. Only four interviewees appeared to successfully enact a version of strengths-based practice that closely mirrored those described by key strengths-based child protection theorists and was fully congruent with their mandated role. They described navigating a shifting balance of collaboration and authority in worker-client relationships based on transparency, impartial judgement, attentiveness to the worker-client interaction and the value that clients were fellow human beings. Their accounts extend current conceptualisations of the worker-client relationship in strengths-based child protection work and are congruent with current understandings of effective mandated relationships. They provide what may be a useful model to help workers understand and navigate relationships in which they must reconcile their own authority and expertise with genuine support for the authority and expertise of their clients.

  6. Toward a brain-based theory of beauty.

    Science.gov (United States)

    Ishizu, Tomohiro; Zeki, Semir

    2011-01-01

    We wanted to learn whether activity in the same area(s) of the brain correlate with the experience of beauty derived from different sources. 21 subjects took part in a brain-scanning experiment using functional magnetic resonance imaging. Prior to the experiment, they viewed pictures of paintings and listened to musical excerpts, both of which they rated on a scale of 1-9, with 9 being the most beautiful. This allowed us to select three sets of stimuli--beautiful, indifferent and ugly--which subjects viewed and heard in the scanner, and rated at the end of each presentation. The results of a conjunction analysis of brain activity showed that, of the several areas that were active with each type of stimulus, only one cortical area, located in the medial orbito-frontal cortex (mOFC), was active during the experience of musical and visual beauty, with the activity produced by the experience of beauty derived from either source overlapping almost completely within it. The strength of activation in this part of the mOFC was proportional to the strength of the declared intensity of the experience of beauty. We conclude that, as far as activity in the brain is concerned, there is a faculty of beauty that is not dependent on the modality through which it is conveyed but which can be activated by at least two sources--musical and visual--and probably by other sources as well. This has led us to formulate a brain-based theory of beauty.

  7. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints.

    Science.gov (United States)

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-12-01

    Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (ptensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint.

  8. Procedimiento para estimar la vida útil de engranajes cilíndricos de acero en base a la resistencia a la fatiga del material y norma AGMA 2101-D04. // A procedure for estimating expected fatigue life on steel cylindrical gears using strength-life theory a

    Directory of Open Access Journals (Sweden)

    G. González Rey

    2008-05-01

    Full Text Available En el trabajo se presenta un procedimiento, fórmulas y relaciones necesarias que permiten determinar un valor de vida útilde referencia previendo la rotura por fatiga de los dientes de acero en ruedas de engranajes cilíndricos de ejes paralelos ycontacto exterior. El procedimiento está fundamentado en considerar la resistencia a la picadura y a flexión de los dientesen engranajes cilíndricos. La base de las fórmulas y relaciones corresponden a la norma AGMA 2101-D04 dirigida alcálculo de la capacidad de carga de engranajes cilíndricos.Palabras claves: Engranaje cilíndrico, duración, fatiga, acero, AGMA 2101._______________________________________________________________________________Abstract.A procedure, formulas and information to estimate a value of expected fatigue life in case of steel cylindrical. Theprocedure is fixed taking into account the pitting resistance (surface fatigue failure and bending strength capacity(volumetric fatigue failure of spur and helical gears. Formulas are based in the AGMA Standard 2105-D04 forcalculation of the load capacity of cylindrical gears.Key words: cylindrical involute gears, lifetime, fatigue resistance, AGMA Standard 2105-D04.

  9. Hand Grip Strength: age and gender stratified normative data in a population-based study

    Directory of Open Access Journals (Sweden)

    Taylor Anne W

    2011-04-01

    Full Text Available Abstract Background The North West Adelaide Health Study is a representative longitudinal cohort study of people originally aged 18 years and over. The aim of this study was to describe normative data for hand grip strength in a community-based Australian population. Secondary aims were to investigate the relationship between body mass index (BMI and hand grip strength, and to compare Australian data with international hand grip strength norms. Methods The sample was randomly selected and recruited by telephone interview. Overall, 3 206 (81% of those recruited participants returned to the clinic during the second stage (2004-2006 which specifically focused on the collection of information relating to musculoskeletal conditions. Results Following the exclusion of 435 participants who had hand pain and/or arthritis, 1366 men and 1312 women participants provided hand grip strength measurement. The study population was relatively young, with 41.5% under 40 years; and their mean BMI was 28.1 kg/m2 (SD 5.5. Higher hand grip strength was weakly related to higher BMI in adults under the age of 30 and over the age of 70, but inversely related to higher BMI between these ages. Australian norms from this sample had amongst the lowest of the hand grip strength of the internationally published norms, except those from underweight populations. Conclusions This population demonstrated higher BMI and lower grip strength in younger participants than much of the international published, population data. A complete exploration of the relationship between BMI and hand grip strength was not fully explored as there were very few participants with BMI in the underweight range. The age and gender grip strength values are lower in younger adults than those reported in international literature.

  10. Evaluation of Bending Strength of Carburized Gears Based on Inferential Identification of Principal Surface Layer Defects

    Science.gov (United States)

    Masuyama, Tomoya; Inoue, Katsumi; Yamanaka, Masashi; Kitamura, Kenichi; Saito, Tomoyuki

    High load capacity of carburized gears originates mainly from the hardened layer and induced residual stress. On the other hand, surface decarburization, which causes a nonmartensitic layer, and inclusions such as oxides and segregation act as latent defects which considerably reduce fatigue strength. In this connection, the authors have proposed a formula of strength evaluation by separately quantifying defect influence. However, the principal defect which limits strength of gears with several different defects remains unclarified. This study presents a method of inferential identification of principal defects based on test results of carburized gears made of SCM420 clean steel, gears with both an artificial notch and nonmartensitic layer at the tooth fillet, and so forth. It clarifies practical uses of presented methods, and strength of carburized gears can be evaluated by focusing on principal defect size.

  11. Research on NDT Technology in Inference of Steel Member Strength Based on Macro/Micro Model

    Directory of Open Access Journals (Sweden)

    Beidou Ding

    2017-01-01

    Full Text Available In consideration of correlations among hardness, chemical composition, grain size, and strength of carbon steel, a new nondestructive testing technology (NDT of inferring the carbon steel strength was explored. First, the hardness test, chemical composition analysis, and metallographic analysis of 162 low-carbon steel samples were conducted. Second, the following works were carried out: (1 quantitative relationship between steel Leeb hardness and carbon steel strength was studied on the basis of regression analysis of experimental data; (2 influences of chemical composition and grain size on tension properties of carbon steel were analyzed on the basis of stepwise regression analysis, and quantitative relationship between conventional compositions and grain size with steel strength was obtained; (3 according to the macro and/or micro factors such as hardness, chemical compositions, and grain size of carbon steel, the fitting formula of steel strength was established based on MLR (multiple linear regressions method. The above relationships and fitting formula based on MLR method could be used to estimate the steel strength with no damage to the structure in engineering practice.

  12. Validating office-based screening for psychosocial strengths and difficulties among youths in foster care.

    Science.gov (United States)

    Jee, Sandra H; Szilagyi, Moira; Conn, Anne-Marie; Nilsen, Wendy; Toth, Sheree; Baldwin, Constance D; Szilagyi, Peter G

    2011-05-01

    To assess the effectiveness of social-emotional screening in the primary care setting for youths in foster care. The setting was a primary care practice for all youth in home-based foster care in 1 county. Subjects were youths, aged 11 to 17 years, and their foster parents; both completed a Strengths and Difficulties Questionnaire at well-child visits. The Strengths and Difficulties Questionnaire is a previously validated 25-item tool that has 5 domains: emotional symptoms; conduct problems; hyperactivity/inattention; peer problems; and prosocial behaviors and an overall total difficulties score. We first compared youth versus parent Strengths and Difficulties Questionnaire scores and then assessed the accuracy of these Strengths and Difficulties Questionnaire scores by comparing them in a subsample of youths (n = 50) with results of home-based structured clinical interviews using the Children's Interview for Psychiatric Syndromes. Of 138 subjects with both youth and parent reports, 78% had prosocial behaviors (strengths), and 70% had 1 or more social-emotional problems. Parents reported significantly more conduct problems (38% vs 16%; P youth. The Strengths and Difficulties Questionnaire had better agreement with the Children's Interview for Psychiatric Syndromes (n = 50) for any Strengths and Difficulties Questionnaire-identified problem for combined youth and foster-parent reports (93%), compared with youth report alone (54%) or parent report alone (71%). Although most youths in foster care have social-emotional problems, most have strengths as well. Youth and foster-parent perspectives on these problems differ. Systematic social-emotional screening in primary care that includes both youth and parent reports can identify youths who may benefit from services.

  13. Fracture strength and fatigue resistance of dental resin-based composites

    NARCIS (Netherlands)

    Keulemans, F.; Palav, P.; Aboushelib, M.M.N.; van Dalen, A.; Kleverlaan, C.J.; Feilzer, A.J.

    2009-01-01

    Objectives: The aim of this study was to evaluate in vitro the influence of fiber-reinforcement on the fracture strength and fatigue resistance of resin-based composites. Methods: One hundred rectangular bar-shaped specimens (2 mm × 2 mm × 25 mm) made of resin-based composite were prepared in a

  14. Mechanical strength development of mortars containing volcanic scoria-based binders with different fineness

    Directory of Open Access Journals (Sweden)

    Aref M. al-Swaidani

    2016-06-01

    Full Text Available The benefits of using natural pozzolan as cement replacement are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. The objective of the study is to investigate the influence of binder fineness on the mechanical strength development of scoria-based binder mortars. In the study, mortar specimens have been produced with four types of binder: one plain Portland cement (control and three scoria-based binders with three replacement levels: 25%, 30% and 35%, respectively. All scoria-based binders have been inter-ground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2/g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Particle size distribution measured by a laser diffractometer has been considered in the study. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. No direct relationship between Blaine and particle size distribution was observed. Effects of Blaine fineness on some physical properties of blended cements such as water demand, setting times and soundness have also been investigated. Further, an estimation equation for strength development incorporating the effects of fineness measured either by Blaine or by particle size distribution has been derived by the authors.

  15. Papain-based gel for biochemical caries removal: influence on microtensile bond strength to dentin

    Directory of Open Access Journals (Sweden)

    Evandro Piva

    2008-12-01

    Full Text Available This study investigated the influence of a papain-based gel (Papacárie for chemo-mechanical caries removal on bond strength to dentin. Human molars were assigned to the following groups: Group 1: sound teeth were flattened to expose dentin; Group 2: after flattening of surfaces, the papain-based gel was applied on the sound dentin; Group 3: overlying enamel from carious teeth was removed and mechanical excavation of dentin was conducted; Group 4: chemo-mechanical excavation of carious dentin was conducted using the papain-based gel. The Prime&Bond NT or Clearfil SE Bond adhesive systems were used for restorative procedures. A microtensile bond strength test was performed, and the modes of failure were determined under SEM. The data were submitted to two-way ANOVA and Tukey's test (p < 0.05. No significant differences were observed between the sound dentin groups. For both excavation methods, Clearfil presented a significantly higher bond strength than Prime&Bond NT. Also, for Clearfil, the mechanically excavated samples disclosed a significantly higher bond strength than the chemo-mechanically ones. For Prime&Bond NT, no significant differences were detected between the excavation methods. Predominance of mixed failures for the sound substrate and of adhesive failures for the carious dentin one was detected. The bond strength to carious dentin of the self-etching system was negatively affected by chemo-mechanical excavation using the papain-based gel.

  16. Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

    International Nuclear Information System (INIS)

    Long-Chao, Zhuo; Shu-Jie, Pang; Hui, Wang; Tao, Zhang

    2009-01-01

    Based on a new approach for designing glassy alloy compositions, bulk Al-based alloys with good glass-forming ability (GFA) are synthesized. The cast Al 86 Si 0.5 Ni 4.06 Co 2.94 Y 6 Sc 0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod. The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 GPa and maximum strength of 1.27 GPa as well as an obvious plastic strain of about 2.4% during compressive deformation. This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability. (condensed matter: structure, mechanical and thermal properties)

  17. Fowler Nordheim theory of carbon nanotube based field emitters

    Energy Technology Data Exchange (ETDEWEB)

    Parveen, Shama; Kumar, Avshish [Department of Physics, Jamia Millia Islamia (Central University), New Delhi (India); Husain, Samina [Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia (Central University), New Delhi (India); Husain, Mushahid, E-mail: mush_reslab@rediffmail.com [Department of Physics, Jamia Millia Islamia (Central University), New Delhi (India)

    2017-01-15

    Field emission (FE) phenomena are generally explained in the frame-work of Fowler Nordheim (FN) theory which was given for flat metal surfaces. In this work, an effort has been made to present the field emission mechanism in carbon nanotubes (CNTs) which have tip type geometry at nanoscale. High aspect ratio of CNTs leads to large field enhancement factor and lower operating voltages because the electric field strength in the vicinity of the nanotubes tip can be enhanced by thousand times. The work function of nanostructure by using FN plot has been calculated with reverse engineering. With the help of modified FN equation, an important formula for effective emitting area (active area for emission of electrons) has been derived and employed to calculate the active emitting area for CNT field emitters. Therefore, it is of great interest to present a state of art study on the complete solution of FN equation for CNTs based field emitter displays. This manuscript will also provide a better understanding of calculation of different FE parameters of CNTs field emitters using FN equation.

  18. Microstructure Effects on Spall Strength of Titanium-based Bulk Metallic Glass Composites

    Science.gov (United States)

    Diaz, Rene; Hofmann, Douglas; Thadhani, Naresh; Georgia Tech Team; GT-JPL Collaboration

    2017-06-01

    The spall strength of Ti-based metallic glass composites is investigated as a function of varying volume fractions (0-80%) of in-situ formed crystalline dendrites. With increasing dendrite content, the topology changes such that neither the harder glass nor the softer dendrites dominate the microstructure. Plate-impact experiments were performed using the 80-mm single-stage gas gun over impact stresses up to 18 GPa. VISAR interferometry was used to obtain rear free-surface velocity profiles revealing the velocity pullback spall failure signals. The spall strengths were higher than for Ti-6Al-4V alloy, and remained high up to impact stress. The influence of microstructure on the spall strength is indicated by the constants of the power law fit with the decompression strain rate. Differences in fracture behavior reveal void nucleation as a dominant mechanism affecting the spall strength. The microstructure with neither 100% glass nor with very high crystalline content, provides the most tortuous path for fracture and therefore highest spall strength. The results allow projection of spall strength predictions for design of in-situ formed metallic glass composites. ARO Grant # W911NF-09 ``1-0403 NASA JPL Contract # 1492033 ``Prime # NNN12AA01C; NSF GRFP Grant #DGE-1148903; and NDSE & G.

  19. Strength Assessment of Broken Rock Postgrouting Reinforcement Based on Initial Broken Rock Quality and Grouting Quality

    Directory of Open Access Journals (Sweden)

    Hongfa Xu

    2017-01-01

    Full Text Available To estimate postgrouting rock mass strength growth is important for engineering design. In this paper, using self-developed indoor pressure-grouting devices, 19 groups of test cubic blocks were made of the different water cement ratio grouting into the broken rock of three kinds of particle sizes. The shear strength parameters of each group under different conditions were tested. Then this paper presents a quantitative calculation method for predicting the strength growth of grouted broken rock. Relational equations were developed to investigate the relationship between the growth rates of uniaxial compressive strength (UCS, absolute value of uniaxial tensile strength (AUTS, internal friction angle, and cohesion for post- to pregrouting broken rock based on Mohr-Coulomb strength criterion. From previous test data, the empirical equation between the growth rate of UCS and the ratio of the initial rock mass UCS to the grout concretion UCS has been determined. The equations of the growth rates of the internal friction coefficient and UCS for grouting broken rock with rock mass rating (RMR and its increment have been established. The calculated results are consistent with the experimental results. These observations are important for engineered design of grouting reinforcement for broken rock mass.

  20. Repair Strength in Simulated Restorations of Methacrylate- or Silorane-Based Composite Resins.

    Science.gov (United States)

    Consani, Rafael Leonardo Xediek; Marinho, Tatiane; Bacchi, Atais; Caldas, Ricardo Armini; Feitosa, Victor Pinheiro; Pfeifer, Carmem Silvia

    2016-01-01

    The study verified the bond strength in simulated dental restorations of silorane- or methacrylate-based composites repaired with methacrylate-based composite. Methacrylate- (P60) or silorane-based (P90) composites were used associated with adhesive (Adper Single Bond 2). Twenty-four hemi-hourglass-shaped samples were repaired with each composite (n=12). Samples were divided according to groups: G1= P60 + Adper Single Bond 2+ P60; G2= P60 + Adper Single Bond 2 + P60 + thermocycling; G3= P90 + Adper Single Bond 2 + P60; and G4= P90 + Adper Single Bond 2 + P60 + thermocycling. G1 and G3 were submitted to tensile test 24 h after repair procedure, and G2 and G4 after submitted to 5,000 thermocycles at 5 and 55 ?#61616;C for 30 s in each bath. Tensile bond strength test was accomplished in an universal testing machine at crosshead speed of 0.5 mm/min. Data (MPa) were analyzed by two-way ANOVA and Tukey's test (5%). Sample failure pattern (adhesive, cohesive in resin or mixed) was evaluated by stereomicroscope at 30?#61655; and images were obtained in SEM. Bond strength values of methacrylate-based composite samples repaired with methacrylate-based composite (G1 and G2) were greater than for silorane-based samples (G3 and G4). Thermocycling decreased the bond strength values for both composites. All groups showed predominance of adhesive failures and no cohesive failure in composite resin was observed. In conclusion, higher bond strength values were observed in methacrylate-based resin samples and greater percentage of adhesive failures in silorane-based resin samples, both composites repaired with methacrylate-based resin.

  1. Configuration-interaction relativistic-many-body-perturbation-theory calculations of photoionization cross sections from quasicontinuum oscillator strengths

    International Nuclear Information System (INIS)

    Savukov, I. M.; Filin, D. V.

    2014-01-01

    Many applications are in need of accurate photoionization cross sections, especially in the case of complex atoms. Configuration-interaction relativistic-many-body-perturbation theory (CI-RMBPT) has been successful in predicting atomic energies, matrix elements between discrete states, and other properties, which is quite promising, but it has not been applied to photoionization problems owing to extra complications arising from continuum states. In this paper a method that will allow the conversion of discrete CI-(R)MPBT oscillator strengths (OS) to photoionization cross sections with minimal modifications of the codes is introduced and CI-RMBPT cross sections of Ne, Ar, Kr, and Xe are calculated. A consistent agreement with experiment is found. RMBPT corrections are particularly significant for Ar, Kr, and Xe and improve agreement with experimental results compared to the particle-hole CI method. As a result, the demonstrated conversion method can be applied to CI-RMBPT photoionization calculations for a large number of multivalence atoms and ions

  2. An approach to higher dimensional theories based on lattice gauge theory

    International Nuclear Information System (INIS)

    Murata, M.; So, H.

    2004-01-01

    A higher dimensional lattice space can be decomposed into a number of four-dimensional lattices called as layers. The higher dimensional gauge theory on the lattice can be interpreted as four-dimensional gauge theories on the multi-layer with interactions between neighboring layers. We propose the new possibility to realize the continuum limit of a five-dimensional theory based on the property of the phase diagram

  3. Continuing Bonds in Bereavement: An Attachment Theory Based Perspective

    Science.gov (United States)

    Field, Nigel P.; Gao, Beryl; Paderna, Lisa

    2005-01-01

    An attachment theory based perspective on the continuing bond to the deceased (CB) is proposed. The value of attachment theory in specifying the normative course of CB expression and in identifying adaptive versus maladaptive variants of CB expression based on their deviation from this normative course is outlined. The role of individual…

  4. High-impact strength acrylic denture base material processed by autoclave.

    Science.gov (United States)

    Abdulwahhab, Salwan Sami

    2013-10-01

    To investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of high-impact strength acrylic denture base material. High Impact Acryl was the heat-cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: control groups in which high-impact strength acrylic resins processed by conventional water-bath processing technique (74°C for 1.5 h then boil for 30 min) and experimental groups in which high-impact strength acrylic resins processed by autoclave at 121°C, 210 kPa .The experimental groups were divided into (fast) groups for 15 min, and (slow) groups for 30 min. To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (Charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. In ANOVA test, there were highly significant differences between the results of the processing techniques in transverse, impact, hardness, and porosity test. The LSD test showed a significant difference between control and fast groups in transverse and hardness tests and a non-significant difference in impact test and a highly significant difference in porosity test; while, there were a highly significant differences between control and slow groups in all examined tests; finally, there were a non-significant difference between fast and slow groups in transverse and porosity tests and a highly significant difference in impact and hardness tests. In the autoclave processing technique, the slow (long) curing cycle improved the tested physical and mechanical properties as compared with the fast (short) curing cycle. The autoclave processing technique improved the tested physical and mechanical properties of High Impact Acryl. Copyright © 2013 Japan Prosthodontic Society

  5. Recursive renormalization group theory based subgrid modeling

    Science.gov (United States)

    Zhou, YE

    1991-01-01

    Advancing the knowledge and understanding of turbulence theory is addressed. Specific problems to be addressed will include studies of subgrid models to understand the effects of unresolved small scale dynamics on the large scale motion which, if successful, might substantially reduce the number of degrees of freedom that need to be computed in turbulence simulation.

  6. Observational attachment theory-based parenting measures predict children's attachment narratives independently from social learning theory-based measures.

    Science.gov (United States)

    Matias, Carla; O'Connor, Thomas G; Futh, Annabel; Scott, Stephen

    2014-01-01

    Conceptually and methodologically distinct models exist for assessing quality of parent-child relationships, but few studies contrast competing models or assess their overlap in predicting developmental outcomes. Using observational methodology, the current study examined the distinctiveness of attachment theory-based and social learning theory-based measures of parenting in predicting two key measures of child adjustment: security of attachment narratives and social acceptance in peer nominations. A total of 113 5-6-year-old children from ethnically diverse families participated. Parent-child relationships were rated using standard paradigms. Measures derived from attachment theory included sensitive responding and mutuality; measures derived from social learning theory included positive attending, directives, and criticism. Child outcomes were independently-rated attachment narrative representations and peer nominations. Results indicated that Attachment theory-based and Social Learning theory-based measures were modestly correlated; nonetheless, parent-child mutuality predicted secure child attachment narratives independently of social learning theory-based measures; in contrast, criticism predicted peer-nominated fighting independently of attachment theory-based measures. In young children, there is some evidence that attachment theory-based measures may be particularly predictive of attachment narratives; however, no single model of measuring parent-child relationships is likely to best predict multiple developmental outcomes. Assessment in research and applied settings may benefit from integration of different theoretical and methodological paradigms.

  7. Design and Evaluation of a Wireless Sensor Network Based Aircraft Strength Testing System

    Science.gov (United States)

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system. PMID:22408521

  8. Compressive strength and microstructural analysis of fly ash/palm oil fuel ash based geopolymer mortar

    International Nuclear Information System (INIS)

    Ranjbar, Navid; Mehrali, Mehdi; Behnia, Arash; Alengaram, U. Johnson; Jumaat, Mohd Zamin

    2014-01-01

    Highlights: • Results show POFA is adaptable as replacement in FA based geopolymer mortar. • The increase in POFA/FA ratio delay of the compressive development of geopolymer. • The density of POFA based geoploymer is lower than FA based geopolymer mortar. - Abstract: This paper presents the effects and adaptability of palm oil fuel ash (POFA) as a replacement material in fly ash (FA) based geopolymer mortar from the aspect of microstructural and compressive strength. The geopolymers developed were synthesized with a combination of sodium hydroxide and sodium silicate as activator and POFA and FA as high silica–alumina resources. The development of compressive strength of POFA/FA based geopolymers was investigated using X-ray florescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and field emission scanning electron microscopy (FESEM). It was observed that the particle shapes and surface area of POFA and FA as well as chemical composition affects the density and compressive strength of the mortars. The increment in the percentages of POFA increased the silica/alumina (SiO 2 /Al 2 O 3 ) ratio and that resulted in reduction of the early compressive strength of the geopolymer and delayed the geopolymerization process

  9. Design and evaluation of a wireless sensor network based aircraft strength testing system.

    Science.gov (United States)

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system.

  10. Electric field strength determination in filamentary DBDs by CARS-based four-wave mixing

    Science.gov (United States)

    Boehm, Patrick; Kettlitz, Manfred; Brandenburg, Ronny; Hoeft, Hans; Czarnetzki, Uwe

    2016-09-01

    The electric field strength is a basic parameter of non-thermal plasmas. Therefore, a profound knowledge of the electric field distribution is crucial. In this contribution a four wave mixing technique based on Coherent Anti-Stokes Raman spectroscopy (CARS) is used to measure electric field strengths in filamentary dielectric barrier discharges (DBDs). The discharges are operated with a pulsed voltage in nitrogen at atmospheric pressure. Small amounts hydrogen (10 vol%) are admixed as tracer gas to evaluate the electric field strength in the 1 mm discharge gap. Absolute values of the electric field strength are determined by calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. Alteration of the electric field strength has been observed during the internal polarity reversal and the breakdown process. In this case the major advantage over emission based methods is that this technique can be used independently from emission, e.g. in the pre-phase and in between two consecutive, opposite discharge pulses where no emission occurs at all. This work was supported by the Deutsche Forschungsgemeinschaft, Forschergruppe FOR 1123 and Sonderforschungsbereich TRR 24 ``Fundamentals of complex plasmas''.

  11. The Prediction of Item Parameters Based on Classical Test Theory and Latent Trait Theory

    Science.gov (United States)

    Anil, Duygu

    2008-01-01

    In this study, the prediction power of the item characteristics based on the experts' predictions on conditions try-out practices cannot be applied was examined for item characteristics computed depending on classical test theory and two-parameters logistic model of latent trait theory. The study was carried out on 9914 randomly selected students…

  12. Microtensile strength of spruce pine after exposure to acids and bases

    Science.gov (United States)

    Floyd G. Manwiller; Paul R. Godfrey

    1972-01-01

    Earlywood and latewood microtensile specimens from 12 trees of Pinus glabra Wal. were subjected to 10-percent solution of 5 acids and 3 bases at 90oC for up to 3 hours. Hydrochloric and sulfuric acids were the most damaging, lowering maximum tensile strength 27 and 17 percent in earlywood and 36 and 39 percent in latewood; they...

  13. Acceptability and Feasibility Results of a Strength-Based Skills Training Program for Dementia Caregiving Dyads

    Science.gov (United States)

    Judge, Katherine S.; Yarry, Sarah J.; Orsulic-Jeras, Silvia

    2010-01-01

    Purpose: The current article provides an in-depth description of a dyadic intervention for individuals with dementia and their family caregivers. Using a strength-based approach, caregiving dyads received skills training across 5 key areas: (a) education regarding dementia and memory loss, (b) effective communication, (c) managing memory loss, (d)…

  14. Solution-Focused Therapy: Strength-Based Counseling for Children with Social Phobia

    Science.gov (United States)

    George, Cindy M.

    2008-01-01

    Solution-focused therapy is proposed as an effective strength-based model for children with social phobia. Social phobia is described along with the etiology and prevailing treatment approaches. A case illustration demonstrates the application of solution-focused therapy with a child who experienced social phobia. Implications for counseling and…

  15. Using Strength-Based Approaches to Explore Pretreatment Change in Men Who Abuse Their Partners

    Science.gov (United States)

    Curwood, Susan Eckerle; DeGeer, Ian; Hymmen, Peter; Lehmann, Peter

    2011-01-01

    Group work with men who batter has traditionally consisted predominantly of psychoeducational programs that ignore concepts such as self-determination, goal setting, and positive engagement with men. More recently, this paradigm has begun to shift to include cognitive approaches and the utilization of strength-based strategies. The present sample…

  16. A Strengths-Based Group Intervention for Women Who Experienced Child Sexual Abuse

    Science.gov (United States)

    Walker-Williams, Hayley J.; Fouché, Ansie

    2017-01-01

    Purpose: This study evaluated the benefits of a ''survivor to thriver'' strengths-based group intervention program to facilitate posttraumatic growth in women survivors of child sexual abuse. Method: A quasi-experimental, one group, pretest, posttest, time-delay design was employed using qualitative methods to evaluate the benefits of the…

  17. The Strength-Based Counseling Model: A Paradigm Shift in Psychology

    Science.gov (United States)

    Smith, Elsie J.

    2006-01-01

    Sometimes, it is difficult for a profession to move forward because its members interpret emerging conceptual models from the perspective of old frameworks. Each of the five reactants in this issue of "The Counseling Psychologist" interpreted the strength-based counseling model within their own self-adopted framework--Adlerian psychology, role…

  18. Towards a Strength-Based Juvenile Correctional Facility: Sustainability and Effects of an Institutional Transformation

    Science.gov (United States)

    Barton, William H.; Mackin, Juliette R.

    2012-01-01

    In 2006, the administration of a state-run, secure juvenile correctional facility initiated an attempt to transform its institutional culture using a strength-based approach to assessment and case planning. This resulted in a rapid improvement in institutional climate. The current study revisits this setting several years later to see if those…

  19. Strength-based Supervision: Frameworks, Current Practice, and Future Directions A Wu-wei Method.

    Science.gov (United States)

    Edwards, Jeffrey K.; Chen, Mei-Whei

    1999-01-01

    Discusses a method of counseling supervision similar to the wu-wei practice in Zen and Taoism. Suggests that this strength-based method and an understanding of isomorphy in supervisory relationships are the preferred practice for the supervision of family counselors. States that this model of supervision potentiates the person-of-the-counselor.…

  20. Microtensile strength of spruce pine after exposure to acids and bases

    Science.gov (United States)

    F.G. Manwiller; P.R. Godfrey

    1973-01-01

    Earlywood and latewood microtensile specimens from 12 trees of Pinus glabra Walt. were subjected to 10-percent solution of 5 acids and 3 bases at good for up to 3 hours. Hydrochloric and sulfuric acids were the most damaging, lowering maximum tensile strength 27 and 17 percent in earlywood and 36 and 39 percent in latewood; they reduced work to maximum load 40 percent...

  1. SMD-based numerical stochastic perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Brida, Mattia [Universita di Milano-Bicocca, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano-Bicocca (Italy); Luescher, Martin [CERN, Theoretical Physics Department, Geneva (Switzerland); AEC, Institute for Theoretical Physics, University of Bern (Switzerland)

    2017-05-15

    The viability of a variant of numerical stochastic perturbation theory, where the Langevin equation is replaced by the SMD algorithm, is examined. In particular, the convergence of the process to a unique stationary state is rigorously established and the use of higher-order symplectic integration schemes is shown to be highly profitable in this context. For illustration, the gradient-flow coupling in finite volume with Schroedinger functional boundary conditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory. The scaling behaviour of the algorithm turns out to be rather favourable in this case, which allows the computations to be driven close to the continuum limit. (orig.)

  2. SMD-based numerical stochastic perturbation theory

    International Nuclear Information System (INIS)

    Dalla Brida, Mattia; Luescher, Martin

    2017-01-01

    The viability of a variant of numerical stochastic perturbation theory, where the Langevin equation is replaced by the SMD algorithm, is examined. In particular, the convergence of the process to a unique stationary state is rigorously established and the use of higher-order symplectic integration schemes is shown to be highly profitable in this context. For illustration, the gradient-flow coupling in finite volume with Schroedinger functional boundary conditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory. The scaling behaviour of the algorithm turns out to be rather favourable in this case, which allows the computations to be driven close to the continuum limit. (orig.)

  3. SMD-based numerical stochastic perturbation theory

    Science.gov (United States)

    Dalla Brida, Mattia; Lüscher, Martin

    2017-05-01

    The viability of a variant of numerical stochastic perturbation theory, where the Langevin equation is replaced by the SMD algorithm, is examined. In particular, the convergence of the process to a unique stationary state is rigorously established and the use of higher-order symplectic integration schemes is shown to be highly profitable in this context. For illustration, the gradient-flow coupling in finite volume with Schrödinger functional boundary conditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory. The scaling behaviour of the algorithm turns out to be rather favourable in this case, which allows the computations to be driven close to the continuum limit.

  4. FDI theories. A location-based approach

    Directory of Open Access Journals (Sweden)

    Popovici, Oana Cristina

    2014-09-01

    Full Text Available Given the importance of FDI for the economic growth of both home and host countries, the aim of this paper is to assess the importance granted to location advantages during the development of FDI theory. We start with the earliest theoretical directions as regards FDI location issues and extend our study to describing less debated theories, but of a particular importance for this theme. In this way, we have the opportunity to emphasize the changes in FDI location determinants. We find that a direction of the FDI theories’ expansion is due to the incorporation of new variables on location, although the location advantages are barely mentioned in the first explanations regarding the international activity of the firms.

  5. The empirical bases of the scientific theory

    International Nuclear Information System (INIS)

    Cook, A.

    1996-01-01

    This paper was written according to a speech given by the author at the French Academy of Sciences in Paris on November 14, 1994. In this educational paper, the author tries to explain the origins and limitations of the scientific theories. The aim of science is to allow the edification of a rational framework which situates the observations we can make about the world in which we live. These observations are determined by the human capacities and by the physical world itself. Thus, the structure of our theories is, up to a certain limit, imposed by the observation constraints: for example, the relationship between the time evolution equation in quantum mechanics and the definition of the atomic time standard, or between the restricted relativity and the observation of far away events using the electromagnetic radiation. A corollary is that several physical systems can be assimilated to the representation of abstract groups, and this is a possible explanation of mathematics power in scientific theories. However, the group representation is not suitable for all natural systems, such as those referring to a chaotic dynamics. In this case, and in others in physics and biology, questions exist which cannot be answered by the simple study of the natural world

  6. Superior creep strength of a nickel-based superalloy produced by selective laser melting

    Energy Technology Data Exchange (ETDEWEB)

    Pröbstle, M., E-mail: martin.proebstle@fau.de [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Neumeier, S.; Hopfenmüller, J.; Freund, L.P. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany); Niendorf, T. [Institut für Werkstofftechnik (Materials Engineering), Universität Kassel, Mönchebergstr. 3, D-34125 Kassel (Germany); Schwarze, D. [SLM Solutions GmbH, Roggenhorster Straße 9c, D-23556 Lübeck (Germany); Göken, M. [Department of Materials Science & Engineering Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstraße 5, D-91058 Erlangen (Germany)

    2016-09-30

    The creep properties of a polycrystalline nickel-based superalloy produced via selective laser melting were investigated in this study. All heat treatment conditions of the additively manufactured material show superior creep strength compared to conventional cast and wrought material. The process leads to a microstructure with fine subgrains. In comparison to conventional wrought material no Niobium rich δ phase is necessary to control the grain size and thus more Niobium is available for precipitation hardening and solid solution strengthening resulting in improved creep strength.

  7. Support vector machines optimization based theory, algorithms, and extensions

    CERN Document Server

    Deng, Naiyang; Zhang, Chunhua

    2013-01-01

    Support Vector Machines: Optimization Based Theory, Algorithms, and Extensions presents an accessible treatment of the two main components of support vector machines (SVMs)-classification problems and regression problems. The book emphasizes the close connection between optimization theory and SVMs since optimization is one of the pillars on which SVMs are built.The authors share insight on many of their research achievements. They give a precise interpretation of statistical leaning theory for C-support vector classification. They also discuss regularized twi

  8. Graph-based linear scaling electronic structure theory

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Anders M. N., E-mail: amn@lanl.gov; Negre, Christian F. A.; Cawkwell, Marc J.; Swart, Pieter J.; Germann, Timothy C.; Bock, Nicolas [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Mniszewski, Susan M.; Mohd-Yusof, Jamal; Wall, Michael E.; Djidjev, Hristo [Computer, Computational, and Statistical Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Rubensson, Emanuel H. [Division of Scientific Computing, Department of Information Technology, Uppsala University, Box 337, SE-751 05 Uppsala (Sweden)

    2016-06-21

    We show how graph theory can be combined with quantum theory to calculate the electronic structure of large complex systems. The graph formalism is general and applicable to a broad range of electronic structure methods and materials, including challenging systems such as biomolecules. The methodology combines well-controlled accuracy, low computational cost, and natural low-communication parallelism. This combination addresses substantial shortcomings of linear scaling electronic structure theory, in particular with respect to quantum-based molecular dynamics simulations.

  9. Damage formation, fatigue behavior and strength properties of ZrO{sub 2}-based ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Kozulin, A. A., E-mail: kozulyn@ftf.tsu.ru; Kulkov, S. S. [Tomsk State University, Tomsk, 634050 (Russian Federation); Narikovich, A. S.; Leitsin, V. N. [Immanuel Kant Baltic Federal University, Kaliningrad, 236041 (Russian Federation); Kulkov, S. N., E-mail: kulkov@ispms.ru [Tomsk State University, Tomsk, 634050 (Russian Federation); Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2016-08-02

    It is suggested that a non-destructive testing technique using a three-dimensional X-ray tomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO{sub 2}-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91–0.98, 0.8–0.83, and 0.73–0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical properties of the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 10{sup 5} stress cycles is in the range 33–34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material.

  10. Influence of silica fume and fly ash on hydration, microstructure and strength of cement based mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Kaimao

    1992-10-01

    The influence of fly ash and silica fume on the hydration, microstructure and strength of cement-based mixtures was investigated. A literature review of the hydration processes, compressive strength development, and microstructure of Portland cement is presented, followed by description of materials and specimens preparation and experimental methodology. It was found that silica fume retards cement hydration at low water/concrete ratios. It reduces calcium hydroxide significantly and increases the amount of hydrates at early ages. Fly ash retards hydration more significantly at high water/concrete ratios than at low ratios. The combination of silica fume and fly ash further retards hydration at one day. Silica fume dominates the reaction with calcium hydroxide. Silica fume significantly increases early strength of mortars and concrete, while fly ash reduces early strength. Silica fume can substantially increase strength of fly ash mortar and concrete after 7 days. Silica fume refines pores in the range 100-500 A, while fly ash mortars exhibit gradual pore refinement as hydration proceeds. Silica fume dominates the pore refinement if used with fly ash. 89 refs., 74 figs., 16 tabs.

  11. Damage Analysis and Evaluation of High Strength Concrete Frame Based on Deformation-Energy Damage Model

    Directory of Open Access Journals (Sweden)

    Huang-bin Lin

    2015-01-01

    Full Text Available A new method of characterizing the damage of high strength concrete structures is presented, which is based on the deformation energy double parameters damage model and incorporates both of the main forms of damage by earthquakes: first time damage beyond destruction and energy consumption. Firstly, test data of high strength reinforced concrete (RC columns were evaluated. Then, the relationship between stiffness degradation, strength degradation, and ductility performance was obtained. And an expression for damage in terms of model parameters was determined, as well as the critical input data for the restoring force model to be used in analytical damage evaluation. Experimentally, the unloading stiffness was found to be related to the cycle number. Then, a correction for this changing was applied to better describe the unloading phenomenon and compensate for the shortcomings of structure elastic-plastic time history analysis. The above algorithm was embedded into an IDARC program. Finally, a case study of high strength RC multistory frames was presented. Under various seismic wave inputs, the structural damages were predicted. The damage model and correction algorithm of stiffness unloading were proved to be suitable and applicable in engineering design and damage evaluation of a high strength concrete structure.

  12. Damage formation, fatigue behavior and strength properties of ZrO_2-based ceramics

    International Nuclear Information System (INIS)

    Kozulin, A. A.; Kulkov, S. S.; Narikovich, A. S.; Leitsin, V. N.; Kulkov, S. N.

    2016-01-01

    It is suggested that a non-destructive testing technique using a three-dimensional X-ray tomography be applied to detecting internal structural defects and monitoring damage formation in a ceramic composite structure subjected to a bending load. Three-point bending tests are used to investigate the fatigue behavior and mechanical and physical properties of medical-grade ZrO_2-based ceramics. The bending strength and flexural modulus are derived under static conditions at a loading rate of 2 mm/min. The fatigue strength and fatigue limit under dynamic loading are investigated at a frequency of 10 Hz in three stress ranges: 0.91–0.98, 0.8–0.83, and 0.73–0.77 MPa of the static bending strength. The average values of the bending strength and flexural modulus of sintered specimens are 43 MPa and 22 GPa, respectively. The mechanical properties of the ceramics are found to be similar to those of bone tissues. The testing results lead us to conclude that the fatigue limit obtained from 10"5 stress cycles is in the range 33–34 MPa, i.e. it accounts for about 75% of the static bending strength for the test material.

  13. Comparison of Shear Bond Strengths of three resin systems for a Base Metal Alloy bonded to

    Directory of Open Access Journals (Sweden)

    Jlali H

    1999-12-01

    Full Text Available Resin-bonded fixed partial dentures (F.P.D can be used for conservative treatment of partially edentulous"npatients. There are numerous studies regarding the strength of resin composite bond to base meta! alloys. Shear bond"nstrength of three resin systems were invistigated. In this study these systems consisted of: Panavia Ex, Mirage FLC and"nMarathon V. Thirty base metal specimens were prepared from rexillium III alloy and divided into three groups. Then each"ngroup was bonded to enamel of human extracted molar teeth with these systems. All of specimens were stored in water at"n37ac for 48 hours. A shear force was applied to each specimen by the instron universal testing machine. A statistical"nevaluation of the data using one-way analysis of variance showed that there was highly significant difference (P<0.01"nbetween the bond strengths of these three groups."nThe base metal specimens bonded with panavia Ex luting agent, exhibited the highest mean bond strength. Shear bond"nstrength of the specimens bonded to enamel with Mirage F1C showed lower bond strenght than panavia EX. However, the"nlowest bond strength was obtained by the specimens bonded with Marathon V.

  14. Not sending the message: A low prevalence of strength-based exercise participation in rural and regional Central Queensland.

    Science.gov (United States)

    Dalbo, Vincent J; Czerepusko, James B; Tucker, Patrick S; Kingsley, Michael I; Moon, Jordan R; Young, Kaelin; Scanlan, Aaron T

    2015-10-01

    The primary aim of this study was to determine the prevalence of current strength-based exercise in rural and regional populations of Central Queensland. The secondary aim was to examine the proportion of residents from various demographic groups who currently partake in strength-based exercise to allow for targeted strength training campaigns. A cross-sectional, survey-based experimental design was followed. Rural and regional Australia. Rural and regional community-dwelling individuals living in Central Queensland and aged 18 years and older. Survey data was collected in October and November 2010 as part of the Central Queensland University Social Survey. Strength-based exercise participation, gender, age, income, years of education, self-reported physical activity and perception of health. Participation in strength-based exercise was 13.2%. Women were less likely to partake in strength-based exercise than male, and ≥55 year old adults were less likely to partake in strength-based exercise than 18-34 year old adults. Participation in strength-based exercise was found to increase with years of education, self-reported physical activity and self-rated health. The prevalence of adults in rural and regional Central Queensland engaging in strength-based exercise is low. Exercise physiologists, clinicians and government officials must work together to ensure that this form of exercise is acknowledged as a vital component of health in rural and regional areas. © 2015 National Rural Health Alliance Inc.

  15. [Preliminary study of bonding strength between diatomite-based dental ceramic and veneering porcelains].

    Science.gov (United States)

    Lu, Xiao-li; Gao, Mei-qin; Cheng, Yu-ye; Zhang, Fei-min

    2015-04-01

    In order to choose the best veneering porcelain for diatomite-based dental ceramic substrate, the bonding strength between diatomite-based dental ceramics and veneering porcelains was measured, and the microstructure and elements distribution of interface were analyzed. The coefficient of thermal expansion (CTE) of diatomite-based dental ceramics was detected by dilatometry. Three veneering porcelain materials were selected with the best CTE matching including alumina veneering porcelain (group A), titanium porcelain veneering porcelain (group B), and E-max veneering porcelain (group C). Shear bonding strength was detected. SEM and EDS were used to observe the interface microstructure and element distribution. Statistical analysis was performed using SPSS 17.0 software package. The CTE of diatomite-based dental ceramics at 25-500 degrees centigrade was 8.85×10-6K-1. The diatomite-based substrate ceramics combined best with group C. Shear bonding strength between group A and C and group B and C both showed significant differences(P<0.05). SEM and EDS showed that the interface of group C sintered tightly and elements permeated on both sides of the interface. The diatomite-based substrate ceramics combines better with E-max porcelain veneer.

  16. Task-Based Language Teaching and Expansive Learning Theory

    Science.gov (United States)

    Robertson, Margaret

    2014-01-01

    Task-Based Language Teaching (TBLT) has become increasingly recognized as an effective pedagogy, but its location in generalized sociocultural theories of learning has led to misunderstandings and criticism. The purpose of this article is to explain the congruence between TBLT and Expansive Learning Theory and the benefits of doing so. The merit…

  17. A density functional theory-based chemical potential equalisation

    Indian Academy of Sciences (India)

    A chemical potential equalisation scheme is proposed for the calculation of these quantities and hence the dipole polarizability within the framework of density functional theory based linear response theory. The resulting polarizability is expressed in terms of the contributions from individual atoms in the molecule. A few ...

  18. Shear Bond Strength of Bracket Bases to Adhesives Based on Bracket Base Design

    Science.gov (United States)

    2016-04-13

    shear bond value when compared to the traditional mesh based orthodontic bracket. Methods: The experimental design included 4 test groups, each... Experimental Design……………………………………………………..…………8 B. Statistical Management of Data………………………………………………….26 IV. RESULTS………………………………………………………………………………28...tooth through which forces may be applied. Through diligent research efforts, clinical experience, and trial and error, this attachment apparatus to

  19. An Elasto-Plastic Damage Model for Rocks Based on a New Nonlinear Strength Criterion

    Science.gov (United States)

    Huang, Jingqi; Zhao, Mi; Du, Xiuli; Dai, Feng; Ma, Chao; Liu, Jingbo

    2018-05-01

    The strength and deformation characteristics of rocks are the most important mechanical properties for rock engineering constructions. A new nonlinear strength criterion is developed for rocks by combining the Hoek-Brown (HB) criterion and the nonlinear unified strength criterion (NUSC). The proposed criterion takes account of the intermediate principal stress effect against HB criterion, as well as being nonlinear in the meridian plane against NUSC. Only three parameters are required to be determined by experiments, including the two HB parameters σ c and m i . The failure surface of the proposed criterion is continuous, smooth and convex. The proposed criterion fits the true triaxial test data well and performs better than the other three existing criteria. Then, by introducing the Geological Strength Index, the proposed criterion is extended to rock masses and predicts the test data well. Finally, based on the proposed criterion, a triaxial elasto-plastic damage model for intact rock is developed. The plastic part is based on the effective stress, whose yield function is developed by the proposed criterion. For the damage part, the evolution function is assumed to have an exponential form. The performance of the constitutive model shows good agreement with the results of experimental tests.

  20. Learning Theory Foundations of Simulation-Based Mastery Learning.

    Science.gov (United States)

    McGaghie, William C; Harris, Ilene B

    2018-06-01

    Simulation-based mastery learning (SBML), like all education interventions, has learning theory foundations. Recognition and comprehension of SBML learning theory foundations are essential for thoughtful education program development, research, and scholarship. We begin with a description of SBML followed by a section on the importance of learning theory foundations to shape and direct SBML education and research. We then discuss three principal learning theory conceptual frameworks that are associated with SBML-behavioral, constructivist, social cognitive-and their contributions to SBML thought and practice. We then discuss how the three learning theory frameworks converge in the course of planning, conducting, and evaluating SBML education programs in the health professions. Convergence of these learning theory frameworks is illustrated by a description of an SBML education and research program in advanced cardiac life support. We conclude with a brief coda.

  1. An overview of advanced high-strength nickel-base alloys for LWR applications

    International Nuclear Information System (INIS)

    Prybylowski, J.; Ballinger, R.G.

    1989-01-01

    This paper reviews our current understanding of the behavior of high strength nickel base alloys used in light water reactor (LWR) applications. Emphasis is placed on understanding the fundamental mechanisms controlling crack propagation in these environments. To provide a foundation for this survey, general mechanisms of stress corrosion cracking and hydrogen embrittlement are first reviewed. The behavior of high strength nickel base alloys in LWR environments, as well as in other relevant environments is then reviewed. Suggested mechanisms of crack propagation are discussed. Alternate alloys and microstructural modifications that may result in improved behavior are presented. It is now clear that, at temperatures near 100C, alloy X-750, the predominant high strength nickel base alloy used today in LWR applications, is susceptible to hydrogen embrittlement. A review of published data from hydrogen embrittlement studies of nickel base superalloys during electrolytic charging and in hydrogen sulfide/brine solutions suggests that other nickel base superalloys are available possessing resistance to hydrogen embrittlement superior to that of alloy X-750. Available results of tests in gaseous hydrogen suggest that reduced grain boundary precipitation and a fine distribution of intragranular precipitates that act as irreversible hydrogen traps is the optimum microstructure for hydrogen embrittlement resistance. 42 refs., 2 figs., 5 tabs

  2. Using Activity Theory as a Base for Investigating Language Teacher ...

    African Journals Online (AJOL)

    Using Activity Theory as a Base for Investigating Language Teacher Education through Digital Technology. ... Log in or Register to get access to full text downloads. ... how the platform has created tensions, contradictions and transformations.

  3. Towards a Theory-Based Framework for Assessing the ...

    African Journals Online (AJOL)

    The theory-based framework attempts to capture ESD's complexity in terms of the ... projects in teacher education institutions in Botswana, a brief description of the ..... How the 'four pillars of learning' relate to education for sustainable human.

  4. Effect of gap distance on tensile strength of preceramic base metal solder joints.

    Science.gov (United States)

    Fattahi, Farnaz; Motamedi, Milad

    2011-01-01

    In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

  5. Microtensile bond strength of silorane-based composite specific adhesive system using different bonding strategies

    Directory of Open Access Journals (Sweden)

    Laura AlveBastos

    2015-02-01

    Full Text Available Objectives The aim of this study was to evaluate the effect of pre-etching on the bond strength of silorane-based composite specific adhesive system to dentin. Materials and Methods Thirty human molars were randomly divided into 5 groups according to the different bonding strategies. For teeth restored with silorane-based composite (Filtek Silorane, 3M ESPE, the specific self-etching adhesive system (Adhesive System P90, 3M ESPE was used with and without pre-etching (Pre-etching/Silorane and Silorane groups. Teeth restored with methacrylate based-composite (Filtek Z250, 3M ESPE were hybridized with the two-step self-etching system (Clearfil SE Bond, Kuraray, with and without pre-etching (Pre-etching/Methacrylate and Methacrylate groups, or three-step adhesive system (Adper Scotchbond Multi-Purpose, 3M ESPE (Three-step/Methacrylate group (n = 6. The restored teeth were sectioned into stick-shaped test specimens (1.0 × 1.0 mm, and coupled to a universal test machine (0.5 mm/min to perform microtensile testing. Results Pre-etching/Methacrylate group presented the highest bond strength values, with significant difference from Silorane and Three-step/Methacrylate groups (p < 0.05. However, it was not significantly different from Preetching/Silorane and Methacrylate groups. Conclusions Pre-etching increased bond strength of silorane-based composite specific adhesive system to dentin.

  6. A Copula-Based Method for Estimating Shear Strength Parameters of Rock Mass

    Directory of Open Access Journals (Sweden)

    Da Huang

    2014-01-01

    Full Text Available The shear strength parameters (i.e., the internal friction coefficient f and cohesion c are very important in rock engineering, especially for the stability analysis and reinforcement design of slopes and underground caverns. In this paper, a probabilistic method, Copula-based method, is proposed for estimating the shear strength parameters of rock mass. The optimal Copula functions between rock mass quality Q and f, Q and c for the marbles are established based on the correlation analyses of the results of 12 sets of in situ tests in the exploration adits of Jinping I-Stage Hydropower Station. Although the Copula functions are derived from the in situ tests for the marbles, they can be extended to be applied to other types of rock mass with similar geological and mechanical properties. For another 9 sets of in situ tests as an extensional application, by comparison with the results from Hoek-Brown criterion, the estimated values of f and c from the Copula-based method achieve better accuracy. Therefore, the proposed Copula-based method is an effective tool in estimating rock strength parameters.

  7. Modern Resource-Based Theory(ies)

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Stieglitz, Nils

    We survey the resource-based view in strategic management, focusing on its roots in economics. We organize our discussion in terms of the Gavetti and Levinthal distinction between a “high church” and a “low church” resource-based view, and argue that these hitherto rather separate streams...

  8. School-Based Management: Theory and Practice.

    Science.gov (United States)

    George, Patricia, Ed.; Potter, Eugenia Cooper, Ed.

    School-based management (SBM), sometimes called site-based management, is fast becoming the hottest restructuring item in the arsenal of reformers, teachers' unions, governors, and legislators who want to change the traditional ways in which schools and school districts do business. This document comprises three main sections with contributions…

  9. Making Theory Come Alive through Practice-based Design Research

    DEFF Research Database (Denmark)

    Markussen, Thomas; Knutz, Eva; Rind Christensen, Poul

    The aim of this paper is to demonstrate how practice-based design research is able not only to challenge, but also to push toward further development of some of the basic assumpstions in emotion theories as used within design research. In so doing, we wish to increase knolwedge on a central...... epistemological question for design research, namely how practice-based design research can be a vehicle for the construction of new theory for design research....

  10. Application of the Theory of Constraints in Project Based Structures

    OpenAIRE

    Martynas Sarapinas; Vytautas Pranas Sūdžius

    2011-01-01

    The article deals with the application of the Theory of Constraints (TOC) in project management. This article involves a short introduction to TOC as a project management method and deep analysis of project management specialties using the TOC: TOC based project planning, timetable management, tasks synchronization, project control and “relay runner work ethic”. Moreover, the article describes traditional and TOC based project management theories in their comparison, and emphasize the main be...

  11. Study on Strength and Microstructure of Cement-Based Materials Containing Combination Mineral Admixtures

    Directory of Open Access Journals (Sweden)

    Meijuan Rao

    2016-01-01

    Full Text Available The compressive strength of complex binders containing two or three blended mineral admixtures in terms of glass powder (GP, limestone powder (LP, and steel slag powder (SP was determined by a battery solution type compressive testing machine. The morphology and microstructure characteristics of complex binder hydration products were also studied by microscopic analysis methods, such as XRD, TG-DTA, and SEM. The mechanical properties of the cement-based materials were analyzed to reveal the most appropriate mineral admixture type and content. The early sample strength development with GP was very slow, but it rapidly grew at later stages. The micro aggregate effect and pozzolanic reaction mutually occurred in the mineral admixture. In the early stage, the micro aggregate effect reduced paste porosity and the small particles connected with the cement hydration products to enhance its strength. In the later stage, the pozzolanic reaction of some components in the complex powder occurred and consumed part of the calcium hydroxide to form C-S-H gel, thus improving the hydration environment. Also, the produced C-S-H gel made the structure more compact, which improved the structure’s strength.

  12. A molecular-mechanics based finite element model for strength prediction of single wall carbon nanotubes

    International Nuclear Information System (INIS)

    Meo, M.; Rossi, M.

    2007-01-01

    The aim of this work was to develop a finite element model based on molecular mechanics to predict the ultimate strength and strain of single wallet carbon nanotubes (SWCNT). The interactions between atoms was modelled by combining the use of non-linear elastic and torsional elastic spring. In particular, with this approach, it was tried to combine the molecular mechanics approach with finite element method without providing any not-physical data on the interactions between the carbon atoms, i.e. the CC-bond inertia moment or Young's modulus definition. Mechanical properties as Young's modulus, ultimate strength and strain for several CNTs were calculated. Further, a stress-strain curve for large deformation (up to 70%) is reported for a nanotube Zig-Zag (9,0). The results showed that good agreement with the experimental and numerical results of several authors was obtained. A comparison of the mechanical properties of nanotubes with same diameter and different chirality was carried out. Finally, the influence of the presence of defects on the strength and strain of a SWNT was also evaluated. In particular, the stress-strain curve a nanotube with one-vacancy defect was evaluated and compared with the curve of a pristine one, showing a reduction of the ultimate strength and strain for the defected nanotube. The FE model proposed demonstrate to be a reliable tool to simulate mechanical behaviour of carbon nanotubes both in the linear elastic field and the non-linear elastic field

  13. Relative strengths of the calf muscles based on MRI volume measurements.

    Science.gov (United States)

    Jeng, Clifford L; Thawait, Gaurav K; Kwon, John Y; Machado, Antonio; Boyle, James W; Campbell, John; Carrino, John A

    2012-05-01

    In 1985, Silver et al. published a cadaver study which determined the relative order of strength of the muscles in the calf. Muscle strength, which is proportional to volume, was obtained by dissecting out the individual muscles, weighing them, and then multiplying by the specific gravity. No similar studies have been performed using {\\it in vivo} measurements of muscle volume. Ten normal subjects underwent 3-Tesla MRI's of both lower extremities using non-fat-saturated T2 SPACE sequences. The volume for each muscle was determined by tracing the muscle contour on sequential axial images and then interpolating the volume using imaging software. The results from this study differ from Silver's original article. The lateral head of the gastrocnemius was found to be stronger than the tibialis anterior muscle. The FHL and EDL muscles were both stronger than the peroneus longus. There was no significant difference in strength between the peroneus longus and brevis muscles. This revised order of muscle strengths in the calf based on in vivo MRI findings may assist surgeons in determining the optimal tendons to transfer in order to address muscle weakness and deformity.

  14. Automatic Mitigation of Sensor Variations for Signal Strength Based Location Systems

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun

    2006-01-01

    n the area of pervasive computing a key concept is context-awareness. One type of context information is location information of wireless network clients. Research in indoor localization of wireless network clients based on signal strength is receiving a lot of attention. However, not much...... of this research is directed towards handling the issue of adapting a signal strength based indoor localization system to the hardware and software of a specific wireless network client, be it a tag, PDA or laptop. Therefore current indoor localization systems need to be manually adapted to work optimally...... with specific hardware and software. A second problem is that for a specific hardware there will be more than one driver available and they will have different properties when used for localization. Therefore the contribution of this paper is twofold. First, an automatic system for evaluating the fitness...

  15. Performance Evaluation of Received Signal Strength Based Hard Handover for UTRAN LTE

    DEFF Research Database (Denmark)

    Anas, Mohmmad; Calabrese, Francesco Davide; Mogensen, Preben

    2007-01-01

    This paper evaluates the hard handover performance for UTRAN LTE system. The focus is on the impact that received signal strength based hard handover algorithm have on the system performance measured in terms of number of handovers, time between two consecutive handovers and uplink SINR for a user...... about to experience a handover. A handover algorithm based on received signal strength measurements has been designed and implemented in a dynamic system level simulator and has been studied for different parameter sets in a 3GPP UTRAN LTE recommended simulation scenario. The results suggest...... that a downlink measurement bandwidth of 1.25 MHz and a handover margin of 2 dB to 6 dB are the parameters that will lead to the best compromise between average number of handovers and average uplink SINR for user speeds of 3 kmph to 120 kmph....

  16. The effects of strength-based versus deficit-based self-regulated learning strategies on students' effort intentions

    NARCIS (Netherlands)

    Hiemstra, Djoerd; Van Yperen, Nico W.

    In two randomized experiments, one conducted online (n = 174) and one in the classroom (n = 267), we tested the effects of two types of self-regulated learning (SRL) strategies on students’ intentions to put effort into professional development activities: strength-based SRL strategies (i.e.,

  17. Using a strengths-based approach to build caring work environments.

    Science.gov (United States)

    Henry, Linda S; Henry, James D

    2007-12-01

    The current health care environment has a growing shortage of nurses and other health care professionals. Health care organizations face the twofold task of retaining employees and preventing "brain drain". A caring work environment can be instrumental in attracting and retaining productive and loyal employees, leading to increased employee and patient satisfaction and a positively impacted bottom line. A strengths-based approach powerfully and effectively promotes and nurtures a caring work environment in all health care specialties and organizations.

  18. Dilemma strength as a framework for advancing evolutionary game theory. Reply to comments on "Universal scaling for the dilemma strength in evolutionary games"

    Science.gov (United States)

    Wang, Zhen; Kokubo, Satoshi; Jusup, Marko; Tanimoto, Jun

    2015-09-01

    While comprehensive reviews of the literature, by gathering in one place most of the relevant information, undoubtedly steer the development of every scientific field, we found that the comments in response to a review article can be as informative as the review itself, if not more. Namely, reading through the comments on the ideas expressed in Ref. [1], we could identify a number of pressing problems for evolutionary game theory, indicating just how much space there still is for major advances and breakthroughs. In an attempt to bring a sense of order to a multitude of opinions, we roughly classified the comments into three categories, i.e. those concerned with: (i) the universality of scaling in heterogeneous topologies, including empirical dynamic networks [2-8], (ii) the universality of scaling for more general game setups, such as the inclusion of multiple strategies and external features [4,9-11], and (iii) experimental confirmations of the theoretical developments [2,12,13].

  19. Effectiveness of Strengths-Based Case Management for People with Mental Health Problems in Hong Kong

    Directory of Open Access Journals (Sweden)

    Kevin Y. C. Hui

    2016-02-01

    Full Text Available This study examined the effectiveness of a 6-month strengths-based case management intervention with 45 Chinese participants with mental health problems in Hong Kong. Social workers provided service according to the strengths-based case management (SCM model developed at the University of Kansas. Changes in participants’ recovery components (Stage of Recovery Scale, mental health symptoms (GHQ, and satisfaction with life were assessed using a single group pretest and posttest design. Results suggest that participants had some improvement in their autonomy, hope, and overall well-being as well as satisfaction with life after receiving services. No significant improvements in the other recovery components and GHQ score were found. Significantly, a number of participants progressed from stages of being overwhelmed or struggling with disability to stages of living with or beyond disability. Strengths-based practice helped participants develop a transformed self which sees hope and possibility despite the vulnerabilities caused by their illness. Though further refinement and testing are vital, adoption of SCM in Hong Kong mental health services is promising.

  20. An enstrophy-based linear and nonlinear receptivity theory

    Science.gov (United States)

    Sengupta, Aditi; Suman, V. K.; Sengupta, Tapan K.; Bhaumik, Swagata

    2018-05-01

    In the present research, a new theory of instability based on enstrophy is presented for incompressible flows. Explaining instability through enstrophy is counter-intuitive, as it has been usually associated with dissipation for the Navier-Stokes equation (NSE). This developed theory is valid for both linear and nonlinear stages of disturbance growth. A previously developed nonlinear theory of incompressible flow instability based on total mechanical energy described in the work of Sengupta et al. ["Vortex-induced instability of an incompressible wall-bounded shear layer," J. Fluid Mech. 493, 277-286 (2003)] is used to compare with the present enstrophy based theory. The developed equations for disturbance enstrophy and disturbance mechanical energy are derived from NSE without any simplifying assumptions, as compared to other classical linear/nonlinear theories. The theory is tested for bypass transition caused by free stream convecting vortex over a zero pressure gradient boundary layer. We explain the creation of smaller scales in the flow by a cascade of enstrophy, which creates rotationality, in general inhomogeneous flows. Linear and nonlinear versions of the theory help explain the vortex-induced instability problem under consideration.

  1. INVESTIGATION OF FISCAL AND BUDGETARY POLICIES BASED ON ECONOMIC THEORIES

    Directory of Open Access Journals (Sweden)

    EMILIA CAMPEANU

    2011-04-01

    Full Text Available Empirical analysis of fiscal and budgetary policies cannot be achieved without first knowing how they are viewed in the economic theories. This approach is important to indicate the position and implications of fiscal and budgetary policy tools in the economic theory considering their major differences. Therefore, the paper aims is to investigate the fiscal and budgetary policies based on economic theories such as neoclassical, Keynesian and neo-Keynesian theory in order to indicate their divergent points. Once known these approaches at the economic theory level is easier to establish the appropriate measures taking into consideration the framing of a country economy in a certain pattern. This work was supported from the European Social Fund through Sectoral Operational Programme Human Resources Development 2007-2013, project number POSDRU/89/1.5/S/59184 „Performance and excellence in postdoctoral research in Romanian economics science domain” (contract no. 0501/01.11.2010.

  2. Understanding women's mammography intentions: a theory-based investigation.

    Science.gov (United States)

    Naito, Mikako; O'Callaghan, Frances V; Morrissey, Shirley

    2009-01-01

    The present study compared the utility of two models (the Theory of Planned Behavior and Protection Motivation Theory) in identifying factors associated with intentions to undertake screening mammography, before and after an intervention. The comparison was made between the unique components of the two models. The effect of including implementation intentions was also investigated. Two hundred and fifty-one women aged 37 to 69 years completed questionnaires at baseline and following the delivery of a standard (control) or a protection motivation theory-based informational intervention. Hierarchical multiple regressions indicated that theory of planned behavior variables were associated with mammography intentions. Results also showed that inclusion of implementation intention in the model significantly increased the association with mammography intentions. The findings suggest that future interventions aiming to increase screening mammography participation should focus on the theory of planned behavior variables and that implementation intention should also be targeted.

  3. Dynamical theory of subconstituents based on ternary algebras

    International Nuclear Information System (INIS)

    Bars, I.; Guenaydin, M.

    1980-01-01

    We propose a dynamical theory of possible fundamental constituents of matter. Our scheme is based on (super) ternary algebras which are building blocks of Lie (super) algebras. Elementary fields, called ''ternons,'' are associated with the elements of a (super) ternary algebra. Effective gauge bosons, ''quarks,'' and ''leptons'' are constructed as composite fields from ternons. We propose two- and four-dimensional (super) ternon theories whose structures are closely related to CP/sub N/ and Yang-Mills theories and their supersymmetric extensions. We conjecture that at large distances (low energies) the ternon theories dynamically produce effective gauge theories and thus may be capable of explaining the present particle-physics phenomenology. Such a scenario is valid in two dimensions

  4. Strengths-based recruitment and development a practical guide to transforming talent management strategy for business results

    CERN Document Server

    Bibb, Sally

    2016-01-01

    Strengths-Based Recruitment and Development explains how and why strengths-based recruitment (SBR) is having a transformational impact on performance in top companies like Saga, Gap, Starbucks and SABMiller. By shifting the focus from what people can do (competency-based recruitment) to what they naturally enjoy doing, or SBR, these companies have reported results which include a 50% drop in staff turnover, 20% increase in productivity and a 12% increase in customer satisfaction within a matter of months. It is no wonder that organizations in many sectors are adopting this new and powerful approach to improve performance, customer satisfaction and competitive edge. Strengths-Based Recruitment and Development includes case studies and interviews with executive board level leaders. These provide rare insight into how they implemented strengths approaches in their organizations to improve the bottom line and performance. The book shows how strengths-based talent management goes beyond simply recruiting the righ...

  5. Playing styles based on experiential learning theory

    NARCIS (Netherlands)

    Bontchev, Boyan; Vassileva, Dessislava; Aleksieva-Petrova, Adelina; Petrov, Milen

    2018-01-01

    In recent years, many researchers have reported positive outcomes and effects from applying computer games to the educational process. The main preconditions for an effective game-based learning process include the presence of high learning interest and the desire to study hard. Therefore,

  6. A Unifying Theory of Value Based Management

    OpenAIRE

    Weaver, Samuel C.; Weston, J. Fred

    2003-01-01

    We identify four alternative performance metrics used in value based management (VBM). (1) Basic is an intrinsic value analysis (IVA), the discounted cash flow (DCF) methodology. (2) We show that this framework will be consistent with returns to shareholder (RTS, capital gains plus dividends) measured over appropriate time horizons. (3) Economic profit (EP) [also called economic value added (EVA®)] takes from the DCF free cash flow valuation, net operating profits after taxes (NOPAT), divide...

  7. Study on the compressive strength of fly ash based geo polymer concrete

    Science.gov (United States)

    Anand Khanna, Pawan; Kelkar, Durga; Papal, Mahesh; Sekar, S. K.

    2017-11-01

    Introduction of the alternative materials for complete replacement of cement in ordinary concrete will play an important role to control greenhouse gas and its effect. The 100% replacement of binder with fly ash (in integration with potassium hydroxide (koh) and potassium silicate (k2sio3) solutions) in concrete gives a significant alternative to conventional cement concrete. This paper focuses on the effect of alkaline solutions koh and k2sio3 on strength properties of fly ash based geo polymer concrete (fgpc); compared the strength at different molarities of alkaline activator koh at different curing temperature. Fly ash based geo polymer concrete was produced from low calcium fly ash, triggered by addition of koh and k2sio3 solution and by assimilation of superplasticizer for suitable workability. The molarities of potassium hydroxide as 8m, 10m and 12m molarities were used at various curing temperatures such as 60°c, 70 °c and 80°c. Results showed that for given proportion to get maximum compressive strength the optimum molarity of alkaline solution is 12m and optimum curing temperature is 70 °c.

  8. Strength Performance Based on Flexibility from Laterite Soil Using Tire Powder and Micro Silica

    Directory of Open Access Journals (Sweden)

    Behrouz Gordan

    2015-01-01

    Full Text Available In terms of environmental issues and human health, one of the advisable techniques to improve soil behavior is the use of scrap tires for soil structures. According to the literature, Tire-Derived Aggregates (TDA are one of the valuable materials in different field of Geotechnical that can be used. TDA properties correspond to some important factors such as high level of flexible, lightweight, high permeability and economic material comparing with sand. Strength performance based on increasing flexibility from laterite soil is the main goal of this study. For this purpose, tropical laterite soil was mixed using TDA and micro silica (MS. As a research method, unconfined tests were carried for thirteen samples based on different percentage of the additives. As a result, the significant reduction for elasticity modulus and strength was observed when soil mixed just using TDA. In addition, the rate of strain at the peak of the curve was dramatically increased. The best performance was found using 6% additives when the ratio was 3% MS and 3% TDA. In fact, the effect of MS was more to increase strength. To recommend, the seepage controlling will investigate at next.

  9. Novel high-strength Fe-based composite materials with large plasticity

    Energy Technology Data Exchange (ETDEWEB)

    Werniewicz, Katarzna; Kuehn, Uta; Mattern, Norbert; Eckert, Juergen; Siegel, Uwe; Bartusch, Birgit; Schultz, Ludwig [IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Kulik, Tadeusz [Warsaw University of Technology, Faculty of Materials Science and Engineering (Poland)

    2007-07-01

    Among glass-forming alloy systems reported so far, Fe-based bulk metallic glasses play a special role. Compared to other amorphous alloys e.g. Zr-, Ti-based, such glasses show superior mechanical strength. However, due to the general brittleness their wider application as structural materials is strongly restricted. The alternative approach to overcome this defect is to design BMG composites. In this work we present a series of new Fe-Cr-Mo-Ga-(Si,C) composite materials derived from an Fe-Cr-Mo-Ga-C-P-B glassy alloy, with the aim to improve the ductility of this high-strength material. The effect of the composition and the phase formation on the resulting mechanical properties was investigated. It has been found that the formation of a complex microstructure, which essentially consists of soft Ga-rich dendrites embedded in a hard Cr- and Mo-rich matrix, leads to a material with excellent compressive mechanical properties. While the obtained values of true strength are comparable with data reported for Fe-Cr-Mo-Ga-C-P-B BMG, the values of true strain are greatly improved for investigated composites.

  10. Comparison of shear bond strength of four types of orthodontic brackets with different base technologies

    Directory of Open Access Journals (Sweden)

    Gaurang H Chaudhary

    2017-01-01

    Full Text Available Objectives: The aim of this study was to compare the shear bond strength (SBS of brackets systems with four different base technologies. Materials and Methods: Maxillary first premolars were randomly divided into four groups of thirty specimens each: (1 Master Series™ conventional twin, (2 T3™ self-ligating, (3 Victory series™ conventional twin, and (4 H4™ self-ligating brackets. Maxillary first premolars were bracketed using an acid-etch composite system, and the SBS measured using an Instron Universal Testing Machine at a crosshead speed of 2 mm/min. The ANOVA and Tukey's multiple comparison tests were performed with significance predetermined at P ≤ 0.05. Results: The overall mean bond strengths were 8.49 ± 2.93, 10.85 ± 3.34, 9.42 ± 2.97, and 9.73 ± 2.62 for the Groups 1, 2, 3, and 4 brackets, respectively. One-way ANOVA test gave an F = 3.182 with a P = 0.026. The Group 1 and Group 2 were observed to have statistically significant difference with a P = 0.014. Conclusions: The T3 self-ligating one-piece design with microetched Quadra Grip™ base brackets had the highest bond strength. The SBS difference between Group 2, Group 3, and Group 4 was not significant, but the difference between Group 2 and Group 1 was statistically significant.

  11. Simplified non-linear time-history analysis based on the Theory of Plasticity

    DEFF Research Database (Denmark)

    Costa, Joao Domingues

    2005-01-01

    This paper aims at giving a contribution to the problem of developing simplified non-linear time-history (NLTH) analysis of structures which dynamical response is mainly governed by plastic deformations, able to provide designers with sufficiently accurate results. The method to be presented...... is based on the Theory of Plasticity. Firstly, the formulation and the computational procedure to perform time-history analysis of a rigid-plastic single degree of freedom (SDOF) system are presented. The necessary conditions for the method to incorporate pinching as well as strength degradation...

  12. Microtensile bond strength of silorane-based composite specific adhesive system using different bonding strategies

    OpenAIRE

    Bastos, Laura Alves; Sousa, Ana Beatriz Silva; Drubi-Filho, Brahim; Panzeri Pires-de-Souza, Fernanda de Carvalho; Garcia, Lucas da Fonseca Roberti

    2014-01-01

    Objectives The aim of this study was to evaluate the effect of pre-etching on the bond strength of silorane-based composite specific adhesive system to dentin. Materials and Methods Thirty human molars were randomly divided into 5 groups according to the different bonding strategies. For teeth restored with silorane-based composite (Filtek Silorane, 3M ESPE), the specific self-etching adhesive system (Adhesive System P90, 3M ESPE) was used with and without pre-etching (Pre-etching/S...

  13. An ongoing investigation on modeling the strength properties of water-entrained cement-based materials

    DEFF Research Database (Denmark)

    Esteves, L.P.

    2012-01-01

    Water-entrained cement based materials by superabsorbent polymers is a concept that was introduced in the research agenda about a decade ago. However, a recent application in the production of high performance concrete revealed potential weaknesses when the proportioning of this intelligent......-based materials. Beyond the discussion of whether or not the introduction of superabsorbent polymers leads to a strength reduction, this paper uses both experimental and theoretical background to separate the effect of SAP in both pore structure and internal relative humidity and the effect from the active...

  14. Flat punch adhesion: transition from fracture-based to strength-limited pull-off

    International Nuclear Information System (INIS)

    Jiang, Yijie; Turner, Kevin T; Grierson, David S

    2014-01-01

    The adhesion of a cylindrical flat punch to a surface due to interatomic forces is a well-known problem that is important in many applications, including indentation experiments and the adhesion of fibrillar structures. Traditionally, the pull-off force has been related to the work of adhesion and punch geometry via the Kendall solution that uses a Griffith energy balance to assess crack propagation and pull-off. More recently, it has been shown that under certain conditions, notably at small punch diameters, the contact can behave in a ‘strength-limited’ fashion in which the interface separates uniformly rather than via crack propagation. Here, a Maugis-Dugdale-type analysis of power-law-shaped bodies in contact is used to examine the change in behaviour from the fracture-based Kendall solution to strength-limited pull-off for cylindrical flat punches. The transition from fracture-based to strength-limited behaviour is described in terms of a non-dimensional parameter that is similar to previous quantities used to describe the transition and is a function of the punch size, the elasticity of the contact, and the adhesion properties. The results of this relatively simple analysis compare favourably with results from more complex computational simulations. In addition, the results are used to develop a function that quantifies the transition between the Kendall solution and the strength-limited solution in order to facilitate interpretation of adhesion measurements in the transition regime between the two limits. Finally, the power-law analysis is used to assess the sensitivity of the transition to the exact shape of the punch. (paper)

  15. Strength of materials and theory of elasticity in 19th century Italy a brief account of the history of mechanics of solids and structures

    CERN Document Server

    Capecchi, Danilo

    2015-01-01

    This book examines the theoretical foundations underpinning the field of strength of materials/theory of elasticity, beginning from the origins of the modern theory of elasticity. While the focus is on the advances made within Italy during the nineteenth century, these achievements are framed within the overall European context. The vital contributions of Italian mathematicians, mathematical physicists, and engineers in respect of the theory of elasticity, continuum mechanics, structural mechanics, the principle of least work, and graphical methods in engineering are carefully explained and discussed. The book represents a work of historical research that primarily comprises original contributions and summaries of work published in journals. It is directed at those graduates in engineering, but also in architecture, who wish to achieve a more global and critical view of the discipline and will also be invaluable for all scholars of the history of mechanics.

  16. Prototype Theory Based Feature Representation for PolSAR Images

    OpenAIRE

    Huang Xiaojing; Yang Xiangli; Huang Pingping; Yang Wen

    2016-01-01

    This study presents a new feature representation approach for Polarimetric Synthetic Aperture Radar (PolSAR) image based on prototype theory. First, multiple prototype sets are generated using prototype theory. Then, regularized logistic regression is used to predict similarities between a test sample and each prototype set. Finally, the PolSAR image feature representation is obtained by ensemble projection. Experimental results of an unsupervised classification of PolSAR images show that our...

  17. Action-Based Jurisprudence: Praxeological Legal Theory in Relation to Economic Theory, Ethics, and Legal Practice

    Directory of Open Access Journals (Sweden)

    Konrad Graf

    2011-08-01

    Full Text Available Action-based legal theory is a discrete branch of praxeology and the basis of an emerging school of jurisprudence related to, but distinct from, natural law. Legal theory and economic theory share content that is part of praxeology itself: the action axiom, the a priori of argumentation, universalizable property theory, and counterfactual-deductive methodology. Praxeological property-norm justification is separate from the strictly ethical “ought” question of selecting ends in an action context. Examples of action-based jurisprudence are found in existing “Austro-libertarian” literature. Legal theory and legal practice must remain distinct and work closely together if justice is to be found in real cases. Legal theorizing was shaped in religious ethical contexts, which contributed to confused field boundaries between law and ethics. The carrot and stick influence of rulers on theorists has distorted conventional economics and jurisprudence in particular directions over the course of centuries. An action-based approach is relatively immune to such sources of distortion in its methods and conclusions, but has tended historically to be marginalized from conventional institutions for this same reason.

  18. Opera house acoustics based on subjective preference theory

    CERN Document Server

    Ando, Yoichi

    2015-01-01

    This book focuses on opera house acoustics based on subjective preference theory; it targets researchers in acoustics and vision who are working in physics, psychology, and brain physiology. This book helps readers to understand any subjective attributes in relation to objective parameters based on the powerful and workable model of the auditory system. It is reconfirmed here that the well-known Helmholtz theory, which was based on a peripheral model of the auditory system, may not well describe pitch, timbre, and duration as well as the spatial sensations described in this book, nor overall responses such as subjective preference of sound fields and the annoyance of environmental noise.

  19. A Geometrical-based Vertical Gain Correction for Signal Strength Prediction of Downtilted Base Station Antennas in Urban Areas

    DEFF Research Database (Denmark)

    Rodriguez, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard

    2012-01-01

    -based extension to standard empirical path loss prediction models can give quite reasonable accuracy in predicting the signal strength from tilted base station antennas in small urban macro-cells. Our evaluation is based on measurements on several sectors in a 2.6 GHz Long Term Evolution (LTE) cellular network......, with electrical antenna downtilt in the range from 0 to 10 degrees, as well as predictions based on ray-tracing and 3D building databases covering the measurement area. Although the calibrated ray-tracing predictions are highly accurate compared with the measured data, the combined LOS/NLOS COST-WI model...

  20. Residual strength evaluation of corroded pipelines with long defects based upon limit load analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chiodo, Mario S.G.; Ruggieri, Claudio [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Arquitetura Naval e Engenharia Oceanica

    2009-07-01

    Accurate evaluation of the residual strength for corroded pipes remains essential in fitness for service analyses, including repair decisions and life-extension programs, of onshore and offshore oil and gas transportation. As the pipeline infrastructure ages, material loss due to corrosion represents one of the main degradation factors of steel pipes which leads to strength reduction and potential catastrophic failures. Current high resolution methods can precisely measure the geometry of corrosion defects. Despite the improvement of those techniques, they are insufficient to ensure high levels of reliability in the burst pressure assessment because the recognized semi-empirical nature of conventional procedures. This work studies the applicability of a stress based criterion based upon plastic instability to predict the burst pressure of pipelines with axial corrosion defects. Verification studies based on experimental burst tests of large diameter pipes made of API X65 and X100 steels with different defect length showed the effectiveness of the proposed criterion based on {sigma}{sup ref} ={eta}{sigma}{sub u} in failure predictions, even though the {eta} factor exhibits a potential strong dependence of the defect geometry and material properties. In general, the results presented here provide an effective support to the ability of the proposed stress based criterion in the integrity assessment of corroded pipelines. (author)

  1. Evaluating hydrological model performance using information theory-based metrics

    Science.gov (United States)

    The accuracy-based model performance metrics not necessarily reflect the qualitative correspondence between simulated and measured streamflow time series. The objective of this work was to use the information theory-based metrics to see whether they can be used as complementary tool for hydrologic m...

  2. Robust optimization based upon statistical theory.

    Science.gov (United States)

    Sobotta, B; Söhn, M; Alber, M

    2010-08-01

    Organ movement is still the biggest challenge in cancer treatment despite advances in online imaging. Due to the resulting geometric uncertainties, the delivered dose cannot be predicted precisely at treatment planning time. Consequently, all associated dose metrics (e.g., EUD and maxDose) are random variables with a patient-specific probability distribution. The method that the authors propose makes these distributions the basis of the optimization and evaluation process. The authors start from a model of motion derived from patient-specific imaging. On a multitude of geometry instances sampled from this model, a dose metric is evaluated. The resulting pdf of this dose metric is termed outcome distribution. The approach optimizes the shape of the outcome distribution based on its mean and variance. This is in contrast to the conventional optimization of a nominal value (e.g., PTV EUD) computed on a single geometry instance. The mean and variance allow for an estimate of the expected treatment outcome along with the residual uncertainty. Besides being applicable to the target, the proposed method also seamlessly includes the organs at risk (OARs). The likelihood that a given value of a metric is reached in the treatment is predicted quantitatively. This information reveals potential hazards that may occur during the course of the treatment, thus helping the expert to find the right balance between the risk of insufficient normal tissue sparing and the risk of insufficient tumor control. By feeding this information to the optimizer, outcome distributions can be obtained where the probability of exceeding a given OAR maximum and that of falling short of a given target goal can be minimized simultaneously. The method is applicable to any source of residual motion uncertainty in treatment delivery. Any model that quantifies organ movement and deformation in terms of probability distributions can be used as basis for the algorithm. Thus, it can generate dose

  3. An Investigation of Bond Strength of Reinforcing Bars in Fly Ash and GGBS Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Boopalan C.

    2017-01-01

    Full Text Available Geopolymers are amorphous aluminosilicate materials. Geopolymers are binders formed by alkali activation of Geopolymer Source Materials (GSM using an alkaline activator solution. Concretes made using Geopolymer binders are excellent alternative to the Ordinary Portland Cement concretes from strength, durability, and ecological considerations. Especially, usage of industrial waste materials such as Fly Ash and Slags as GSMs considerably lower the carbon footprint of concrete and mitigate the damage due to the unscientific dumping/disposal of these materials. To use the Geopolymer concrete (GPC for reinforced structural members, the composite action of reinforcing bars with Geopolymer concrete i.e. the bond behaviour should be well understood. This paper describes the bond behaviour of 12mm and 16mm dia. bars embedded in Fly ash and GGBS based Geopolymer concrete and conventional Portland Pozzolana cement concrete specimens investigated using the pull-out tests as per Indian Standard Code IS:2770(Part-I; the bond stresses and corresponding slips were found out. The bond stress increased with increase in compressive strength. The peak bond stress was found to be 4.3 times more than the design bond stress as per IS:456-2000. The Geopolymer concretes possess higher bond strength compared to the conventional cement concretes.

  4. Outcomes of a Character Strengths-Based Intervention on Self-Esteem and Self-Efficacy of Psychiatrically Hospitalized Youths.

    Science.gov (United States)

    Toback, Rebecca L; Graham-Bermann, Sandra A; Patel, Paresh D

    2016-05-01

    Mental health treatment approaches based on character strengths can be used to complement the traditional focus on functional impairment. The study tested use of a character strengths-based intervention to enhance the self-esteem and self-efficacy of psychiatrically hospitalized youths. Eighty-one hospitalized adolescents were randomly assigned to intervention or comparison groups. The intervention used the Values in Action Inventory of Strengths for Youth to discover character strengths and incorporate them into coping skills. Self-efficacy and self-esteem were measured at baseline, postintervention, two weeks, and three months. Self-esteem and self-efficacy initially increased in both groups, but only the intervention group showed sustained improvement. The intervention was associated with increased self-efficacy at two weeks and increased self-efficacy and self-esteem at three months. A brief, easily administered character strengths-based intervention may be an adjunctive tool in the treatment of psychiatrically hospitalized youths.

  5. [The effect of core veneer thickness ratio on the flexural strength of diatomite-based dental ceramic].

    Science.gov (United States)

    Jiang, Jie; Zhang, Xin; Gao, Mei-qin; Zhang, Fei-min; Lu, Xiao-li

    2015-06-01

    To evaluate the effect of different core veneer thickness ratios on the flexural strength and failure mode of bilayered diatomite-based dental ceramics. Diatomite-based dental ceramics blocks (16 mm×5.4 mm×1 mm) were sintered with different thickness of veneer porcelains: 0 mm (group A), 0.6 mm (group B), 0.8 mm (group C) and 1.0 mm (group D). Flexural strength was detected and scanning electron microscope was used to observe the interface microstructure. Statistical analysis was performed using SPSS 17.0 software package. With the increase of the thickness of the veneer porcelain, flexural strength of group C showed highest flexural strength up to (277.24±5.47) MPa. Different core veneer thickness ratios can significantly influence the flexural strength of bilayered diatomite-based dental ceramics. Supported by Science and Technology Projects of Nantong City (HS2013010).

  6. Comparison of rate theory based modeling calculations with the surveillance test results of Korean light water reactors

    International Nuclear Information System (INIS)

    Lee, Gyeong Geun; Lee, Yong Bok; Kim, Min Chul; Kwon, Junh Yun

    2012-01-01

    Neutron irradiation to reactor pressure vessel (RPV) steels causes a decrease in fracture toughness and an increase in yield strength while in service. It is generally accepted that the growth of point defect cluster (PDC) and copper rich precipitate (CRP) affects radiation hardening of RPV steels. A number of models have been proposed to account for the embrittlement of RPV steels. The rate theory based modeling mathematically described the evolution of radiation induced microstructures of ferritic steels under neutron irradiation. In this work, we compared the rate theory based modeling calculation with the surveillance test results of Korean Light Water Reactors (LWRs)

  7. Strengths-Based Approaches in College and University Student Housing: Implications for First-Year Students' Retention and Engagement

    Science.gov (United States)

    Soria, Krista M.; Taylor, Leonard, Jr.

    2016-01-01

    Strengths-based approaches are expanding in higher education; however, little is known about the impacts of these approaches in housing and residence life settings. The purpose of this study was to examine the associations between first-year students' strengths interactions in housing and their engagement and retention. The results suggest that…

  8. Well-Being on Campus: Testing the Effectiveness of an Online Strengths-Based Intervention for First Year College Students

    Science.gov (United States)

    Koydemir, Selda; Sun-Selisik, Z. Eda

    2016-01-01

    The present research examined the effectiveness of an 8-week online strengths-based intervention in promoting subjective and psychological well-being of first year university students. The intervention was composed of five modules pertaining to (a) finding and cultivating on character strengths, (b) regulation of emotions and increasing positive…

  9. Contraction theory based adaptive synchronization of chaotic systems

    International Nuclear Information System (INIS)

    Sharma, B.B.; Kar, I.N.

    2009-01-01

    Contraction theory based stability analysis exploits the incremental behavior of trajectories of a system with respect to each other. Application of contraction theory provides an alternative way for stability analysis of nonlinear systems. This paper considers the design of a control law for synchronization of certain class of chaotic systems based on backstepping technique. The controller is selected so as to make the error dynamics between the two systems contracting. Synchronization problem with and without uncertainty in system parameters is discussed and necessary stability proofs are worked out using contraction theory. Suitable adaptation laws for unknown parameters are proposed based on the contraction principle. The numerical simulations verify the synchronization of the chaotic systems. Also parameter estimates converge to their true values with the proposed adaptation laws.

  10. Mechanical strength evaluation of the glass base material in the JRR-3 neutron guide tube

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Tetsuya [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-02-01

    The lifetime of the thermal neutron guide tube installed JRR-3 was investigated after 6 years from their first installation. And it was confirmed that a crack had been piercing into the glass base material of the side plate of the neutron guide tube. The cause of the crack was estimated as a static fatigue of the guide tube where an inside of the tube had been evacuated and stressed as well as an embrittlement of the glass base material by gamma ray irradiation. In this report, we evaluate the mechanical strength of the glass base material and estimate the time when the base material gets fatigue fracture. Furthermore, we evaluate a lifetime of the neutron guide tube and confirm the validity of update timing in 2000 and 2001 when the thermal neutron guide tubes T1 and T2 were exchanged into those using the super mirror. (author)

  11. A density gradient theory based method for surface tension calculations

    DEFF Research Database (Denmark)

    Liang, Xiaodong; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2016-01-01

    The density gradient theory has been becoming a widely used framework for calculating surface tension, within which the same equation of state is used for the interface and bulk phases, because it is a theoretically sound, consistent and computationally affordable approach. Based on the observation...... that the optimal density path from the geometric mean density gradient theory passes the saddle point of the tangent plane distance to the bulk phases, we propose to estimate surface tension with an approximate density path profile that goes through this saddle point. The linear density gradient theory, which...... assumes linearly distributed densities between the two bulk phases, has also been investigated. Numerical problems do not occur with these density path profiles. These two approximation methods together with the full density gradient theory have been used to calculate the surface tension of various...

  12. Continuing bonds in bereavement: an attachment theory based perspective.

    Science.gov (United States)

    Field, Nigel P; Gao, Beryl; Paderna, Lisa

    2005-05-01

    An attachment theory based perspective on the continuing bond to the deceased (CB) is proposed. The value of attachment theory in specifying the normative course of CB expression and in identifying adaptive versus maladaptive variants of CB expression based on their deviation from this normative course is outlined. The role of individual differences in attachment security on effective versus ineffective use of CB in coping with bereavement also is addressed. Finally, the moderating influence of type of loss (e.g., death of a spouse vs. child), culture, and religion on type of CB expression within an overarching attachment framework is discussed.

  13. Application of the Theory of Constraints in Project Based Structures

    Directory of Open Access Journals (Sweden)

    Martynas Sarapinas

    2011-04-01

    Full Text Available The article deals with the application of the Theory of Constraints (TOC in project management. This article involves a short introduction to TOC as a project management method and deep analysis of project management specialties using the TOC: TOC based project planning, timetable management, tasks synchronization, project control and “relay runner work ethic”. Moreover, the article describes traditional and TOC based project management theories in their comparison, and emphasize the main benefits we received as the results of the study. Article in Lithuanian

  14. Strength and corrosion behavior of SiC - based ceramics in hot coal combustion environments

    Energy Technology Data Exchange (ETDEWEB)

    Breder, K.; Parten, R.J. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    As part of an effort to evaluate the use of advanced ceramics in a new generation of coal-fired power plants, four SiC-based ceramics have been exposed to corrosive coal slag in a laboratory furnace and two pilot scale combustors. Initial results indicate that the laboratory experiments are valuable additions to more expensive pilot plant experiments. The results show increased corrosive attack with increased temperature, and that only slight changes in temperature may significantly alter the degree of strength degradation due to corrosive attack. The present results are part of a larger experimental matrix evaluating the behavior of ceramics in the coal combustion environment.

  15. Application of high-strength non-shrink cement based grouting material in nuclear power installations

    International Nuclear Information System (INIS)

    Li Zhong; Zuo Weiwei

    2011-01-01

    This paper briefly describes the related technical requirement of secondary grouting during the process of equipment installation in nuclear power projects. The method and procedure are introduced in detail from the aspects of acceptance, preparation, pouring, collecting and maintenance of the high-strength non-shrinking based pouring cement material, and the cautions during the construction is also provided. The factors affecting the quality of the field grouting is analyzed, and the measures to reduce or eliminate the micro-cracks during the process is provided. (authors)

  16. New high strength technologically ecological and expedient economically advantageous alloys on Fe-C base

    International Nuclear Information System (INIS)

    Kolev, B.V.

    2003-01-01

    The paper presents framework a part of by now obtained results of the authors studies in the period 1967(68) - 2002 about possibilities for obtaining new high-strength and wear resistant cast alloys on, Fe-C base (complex alloyed steels and cast irons of different systems with different structure, reflected in over 125 articles, 15 inventions (patents) and other scientific studies. The paper includes summarized results and discussion. Key words: new austenite steels and cast irons, mechanical characteristics, wear resistance. (Original)

  17. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composite

    Science.gov (United States)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu

    2015-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  18. FEAMAC/CARES Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composites

    Science.gov (United States)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu; Bhatt, Ramakrishna

    2016-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  19. In vitro comparison of the tensile bond strength of denture adhesives on denture bases.

    Science.gov (United States)

    Kore, Doris R; Kattadiyil, Mathew T; Hall, Dan B; Bahjri, Khaled

    2013-12-01

    With several denture adhesives available, it is important for dentists to make appropriate patient recommendations. The purpose of this study was to evaluate the tensile bond strength of denture adhesives on denture base materials at time intervals of up to 24 hours. Fixodent, Super Poligrip, Effergrip, and SeaBond denture adhesives were tested with 3 denture base materials: 2 heat-polymerized (Lucitone 199 and SR Ivocap) and 1 visible-light-polymerized (shade-stable Eclipse). Artificial saliva with mucin was used as a control. Tensile bond strength was tested in accordance with American Dental Association specifications at 5 minutes, 3 hours, 6 hours, 12 hours, and 24 hours after applying the adhesive. Maximum forces before failure were recorded in megapascals (MPa), and the data were subjected to a 2-way analysis of variance (α=.05). All 4 adhesives had greater tensile bond strength than the control. Fixodent, Super Poligrip, and SeaBond had higher tensile bond strength values than Effergrip. All adhesives had the greatest tensile bond strength at 5 minutes and the least at 24 hours. The 3 denture bases produced significantly different results with each adhesive (Padhesives had the greatest tensile bond strength, followed by Ivocap and Eclipse. All 4 adhesives had greater tensile bond strength than the control, and all 4 adhesives were strongest at the 5-minute interval. On all 3 types of denture bases, Effergrip produced significantly lower tensile bond strength, and Fixodent, Super Poligrip, and SeaBond produced significantly higher tensile bond strength. At 24 hours, the adhesive-base combinations with the highest tensile bond strength were Fixodent on Lucitone 199, Fixodent on Eclipse, Fixodent on Ivocap, and Super Poligrip on Ivocap. Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  20. Microtensile bond strength of silorane-based composite specific adhesive system using different bonding strategies.

    Science.gov (United States)

    Bastos, Laura Alves; Sousa, Ana Beatriz Silva; Drubi-Filho, Brahim; Panzeri Pires-de-Souza, Fernanda de Carvalho; Garcia, Lucas da Fonseca Roberti

    2015-02-01

    The aim of this study was to evaluate the effect of pre-etching on the bond strength of silorane-based composite specific adhesive system to dentin. Thirty human molars were randomly divided into 5 groups according to the different bonding strategies. For teeth restored with silorane-based composite (Filtek Silorane, 3M ESPE), the specific self-etching adhesive system (Adhesive System P90, 3M ESPE) was used with and without pre-etching (Pre-etching/Silorane and Silorane groups). Teeth restored with methacrylate based-composite (Filtek Z250, 3M ESPE) were hybridized with the two-step self-etching system (Clearfil SE Bond, Kuraray), with and without pre-etching (Pre-etching/Methacrylate and Methacrylate groups), or three-step adhesive system (Adper Scotchbond Multi-Purpose, 3M ESPE) (Three-step/Methacrylate group) (n = 6). The restored teeth were sectioned into stick-shaped test specimens (1.0 × 1.0 mm), and coupled to a universal test machine (0.5 mm/min) to perform microtensile testing. Pre-etching/Methacrylate group presented the highest bond strength values, with significant difference from Silorane and Three-step/Methacrylate groups (p adhesive system to dentin.

  1. AIRS Observations Based Evaluation of Relative Climate Feedback Strengths on a GCM Grid-Scale

    Science.gov (United States)

    Molnar, G. I.; Susskind, J.

    2012-12-01

    Climate feedback strengths, especially those associated with moist processes, still have a rather wide range in GCMs, the primary tools to predict future climate changes associated with man's ever increasing influences on our planet. Here, we make use of the first 10 years of AIRS observations to evaluate interrelationships/correlations of atmospheric moist parameter anomalies computed from AIRS Version 5 Level-3 products, and demonstrate their usefulness to assess relative feedback strengths. Although one may argue about the possible usability of shorter-term, observed climate parameter anomalies for estimating the strength of various (mostly moist processes related) feedbacks, recent works, in particular analyses by Dessler [2008, 2010], have demonstrated their usefulness in assessing global water vapor and cloud feedbacks. First, we create AIRS-observed monthly anomaly time-series (ATs) of outgoing longwave radiation, water vapor, clouds and temperature profile over a 10-year long (Sept. 2002 through Aug. 2012) period using 1x1 degree resolution (a common GCM grid-scale). Next, we evaluate the interrelationships of ATs of the above parameters with the corresponding 1x1 degree, as well as global surface temperature ATs. The latter provides insight comparable with more traditional climate feedback definitions (e. g., Zelinka and Hartmann, 2012) whilst the former is related to a new definition of "local (in surface temperature too) feedback strengths" on a GCM grid-scale. Comparing the correlation maps generated provides valuable new information on the spatial distribution of relative climate feedback strengths. We argue that for GCMs to be trusted for predicting longer-term climate variability, they should be able to reproduce these observed relationships/metrics as closely as possible. For this time period the main climate "forcing" was associated with the El Niño/La Niña variability (e. g., Dessler, 2010), so these assessments may not be descriptive of longer

  2. Strengths and weaknesses of Problem Based Learning from the professional perspective of registered nurses

    Directory of Open Access Journals (Sweden)

    María Cónsul-Giribet

    2014-10-01

    Full Text Available OBJECTIVE: to identify competency strengths and weaknesses as perceived by nursing professionals who graduated with a integrated curriculum and competency-based through Problem Based Learning in small groups.METHOD: an intrinsic case study method was used, which analyzes this innovation through former students (from the first class with three years of professional experience. The data were collected through a questionnaire and discussion groups.RESULTS: the results show that their competency level is valued in a very satisfactory manner. This level paradoxically contrasts with the lack of theoretical knowledge they perceived at the end of their education, when they started working in clinical practice.CONCLUSIONS: the teaching strategy was key to motivate an in-depth study and arouse the desire to know. In addition, Problem Based Learning favors and reinforces the decision to learn, which is that necessary in the course of professional life.

  3. Object-based attention: strength of object representation and attentional guidance.

    Science.gov (United States)

    Shomstein, Sarah; Behrmann, Marlene

    2008-01-01

    Two or more features belonging to a single object are identified more quickly and more accurately than are features belonging to different objects--a finding attributed to sensory enhancement of all features belonging to an attended or selected object. However, several recent studies have suggested that this "single-object advantage" may be a product of probabilistic and configural strategic prioritizations rather than of object-based perceptual enhancement per se, challenging the underlying mechanism that is thought to give rise to object-based attention. In the present article, we further explore constraints on the mechanisms of object-based selection by examining the contribution of the strength of object representations to the single-object advantage. We manipulated factors such as exposure duration (i.e., preview time) and salience of configuration (i.e., objects). Varying preview time changes the magnitude of the object-based effect, so that if there is ample time to establish an object representation (i.e., preview time of 1,000 msec), then both probability and configuration (i.e., objects) guide attentional selection. If, however, insufficient time is provided to establish a robust object-based representation, then only probabilities guide attentional selection. Interestingly, at a short preview time of 200 msec, when the two objects were sufficiently different from each other (i.e., different colors), both configuration and probability guided attention selection. These results suggest that object-based effects can be explained both in terms of strength of object representations (established at longer exposure durations and by pictorial cues) and probabilistic contingencies in the visual environment.

  4. Shear Bond Strength of Ceramic Brackets with Different Base Designs: Comparative In-vitro Study

    Science.gov (United States)

    Ansari, Mohd. Younus; Agarwal, Deepak K; Bhattacharya, Preeti; Ansar, Juhi; Bhandari, Ravi

    2016-01-01

    Introduction Knowledge about the Shear Bond Strength (SBS) of ceramic brackets with different base design is essential as it affects bond strength to enamel. Aim The aim of the present study was to evaluate and compare the effect of base designs of different ceramic brackets on SBS, and to determine the fracture site after debonding. Materials and Methods Four groups of ceramic brackets and one group of metal brackets with different base designs were used. Adhesive precoated base of Clarity Advanced (APC Flash-free) (Unitek/3M, Monrovia, California), microcrystalline base of Clarity Advanced (Unitek/3M, Monrovia, California), polymer mesh base of InVu (TP Orthodontics, Inc., La Porte, IN, United States), patented bead ball base of Inspire Ice (Ormco, Glendora, California), and a mechanical mesh base of Gemini Metal bracket (Unitek/3M, Monrovia, California). Ten brackets of each type were bonded to 50 maxillary premolars with Transbond XT (Unitek/3M). Samples were stored in distilled water at room temperature for 24 hours and subsequently tested in shear mode on a universal testing machine (Model 3382; Instron Corp., Canton, Massachusetts, USA) at a cross head speed of 1mm/minute with the help of a chisel. The debonded interface was recorded and analyzed to determine the predominant bond failure site under an optical microscope (Stereomicroscope) at 10X magnification. One way analysis of variance (ANOVA) was used to compare SBS. Tukey’s significant differences tests were used for post-hoc comparisons. The Adhesive Remnant Index (ARI) scores were compared by chi-square test. Results Mean SBS of microcrystalline base (27.26±1.73), was the highest followed by bead ball base (23.45±5.09), adhesive precoated base (20.13±5.20), polymer mesh base (17.54±1.91), and mechanical mesh base (17.50±2.41) the least. Comparing the frequency (%) of ARI Score among the groups, chi-square test showed significantly different ARI scores among the groups (χ2 = 34.07, pbrackets

  5. Nano-resonator frequency response based on strain gradient theory

    International Nuclear Information System (INIS)

    Miandoab, Ehsan Maani; Yousefi-Koma, Aghil; Pishkenari, Hossein Nejat; Fathi, Mohammad

    2014-01-01

    This paper aims to explore the dynamic behaviour of a nano-resonator under ac and dc excitation using strain gradient theory. To achieve this goal, the partial differential equation of nano-beam vibration is first converted to an ordinary differential equation by the Galerkin projection method and the lumped model is derived. Lumped parameters of the nano-resonator, such as linear and nonlinear springs and damper coefficients, are compared with those of classical theory and it is demonstrated that beams with smaller thickness display greater deviation from classical parameters. Stable and unstable equilibrium points based on classic and non-classical theories are also compared. The results show that, regarding the applied dc voltage, the dynamic behaviours expected by classical and non-classical theories are significantly different, such that one theory predicts the un-deformed shape as the stable condition, while the other theory predicts that the beam will experience bi-stability. To obtain the frequency response of the nano-resonator, a general equation including cubic and quadratic nonlinearities in addition to parametric electrostatic excitation terms is derived, and the analytical solution is determined using a second-order multiple scales method. Based on frequency response analysis, the softening and hardening effects given by two theories are investigated and compared, and it is observed that neglecting the size effect can lead to two completely different predictions in the dynamic behaviour of the resonators. The findings of this article can be helpful in the design and characterization of the size-dependent dynamic behaviour of resonators on small scales. (paper)

  6. Effects of aerobic and strength-based training on metabolic health indicators in older adults

    Directory of Open Access Journals (Sweden)

    Cumming Sean P

    2010-07-01

    Full Text Available Abstract Background The weakening of the cardiovascular system associated with aging could be countered by increasing levels of physical activity and functional fitness. However, inconsistent findings have been found, and the variety of characteristics of exercise used in previous studies may partly explain that inconsistent results. Objective To investigate the training effect of sixteen weeks of moderate intensity, progressive aerobic and strength-based training on metabolic health of older women and men. Methods Sixty three sedentary individuals (mean (SD age 76 (8 years were randomly assigned to control (n = 31 or exercising (n = 32 groups. The training group was separated to aerobic (n = 18 or strength-based (n = 14. Training took place three times a week. Subjects agreed not to change their diet or lifestyle over the experimental period. Results Exercising group attained after treatment significant differences on body weight, waist circumference, body mass index, diastolic blood pressure, triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol, total cholesterol/HDL-cholesterol relationship, high sensitivity C-reactive protein, and 6-minute walk distance. The control group only had significant differences on waist circumference. Conclusion The training programs produced significant benefits on metabolic health indicators of sedentary older women and men.

  7. The Effects of Eccentric, Velocity-Based Training on Strength and Power in Collegiate Athletes.

    Science.gov (United States)

    Dolezal, Samantha M; Frese, Derek L; Llewellyn, Tamra L

    2016-01-01

    The purpose of this study was to determine if combining velocity-based training with eccentric focus (VEB) and velocity-based training (VBT) results in power and strength gains. Nineteen men and women collegiate track and field athletes participated in this study. The subjects completed a 12-week intervention with either a VEB program or a VBT program. To determine the effectiveness of each program, the subjects completed four exercise tests before and after the training period: vertical jump, medicine ball put test, 1RM projected bench press and 1RM projected squat. There were no significant differences between the VBT results and the VEB results. However, there were significant improvements between the pre-test and post-test measures for each group. There were increases in 1RM projected squat for VEB men, VBT men, and VBT women. There were also significant improvements in the VEB male vertical jump and medicine ball put test pre- to post-intervention. For track and field athletes, both programs may result in strength and power gains, however, the results cannot be used to conclude that one resistance training program is superior.

  8. High melt strength, tear resistant blown film based on poly(lactic acid)

    Science.gov (United States)

    Edmonds, Neil R.; Plimmer, Peter N.; Tanner, Chris

    2015-05-01

    A major problem associated with the commercial manufacture of thin films from PLA is inferior processing characteristics on blown film lines compared to low density polyethylene. PLA has poor melt strength (leading to bubble instability) and develops a permanent crease in the flattened film as it exits the tower of the film line. In addition, the thin film product has poor tear strength and an unacceptable `noise' level when converted into flexible packaging. Furthermore, fabricated articles based on PLA are known to show an unattractive tendency toward dimensional instability. This behaviour is associated with `cold crystallization', a phenomenon which also causes exudation of any plasticizer added for improving flexibility. Blow moulded articles based on PLA also exhibit dimensional sensitivity above 60°C. All of these issues have been overcome by the technology described in this paper. This has been accomplished without loss of the valuable compostability characteristic of PLA; this was confirmed by evaluation of film in a commercial composting operation. These results have been achieved through novel reactive compounding technology which: (a) Creates a PLA-rich structure containing long chain crosslinks, (b) generates a low glass transition temperature phase covalently bonded to the PLA structure, and (c) provides a material which performs like LDPE in a blown film manufacturing operation. The technology developed is covered by NZ Patent 580231 (3). The patent is held by UniServices Ltd, The University of Auckland, New Zealand.

  9. Strengths-Based Nursing: A Process for Implementing a Philosophy Into Practice.

    Science.gov (United States)

    Gottlieb, Laurie N; Gottlieb, Bruce

    2017-08-01

    Strengths-Based Nursing (SBN) is both a philosophy and value-driven approach that can guide clinicians, educators, manager/leaders, and researchers. SBN is rooted in principles of person/family centered care, empowerment, relational care, and innate health and healing. SBN is family nursing yet not all family nursing models are strengths-based. The challenge is how to translate a philosophy to change practice. In this article, we describe a process of implementation that has organically evolved of a multi-layered and multi-pronged approach that involves patients and families, clinicians, educators, leaders, managers, and researchers as well as key stakeholders including union leaders, opinion leaders, and policy makers from both nursing and other disciplines. There are two phases to the implementation process, namely, Phase 1: pre-commitment/pre-adoption and Phase 2: adoption. Each phase consists of distinct steps with accompanying strategies. These phases occur both sequentially and concurrently. Facilitating factors that enable the implementation process include values which align, readiness to accept SBN, curiosity-courage-commitment on the part of early adopters, a critical mass of early adopters, and making SBN approach both relevant and context specific.

  10. A multi-component Zr alloy with comparable strength and Higher plasticity than Zr-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Liang, S.X.; Yin, L.X.; Ma, M.Z.; Jing, R.; Yu, P.F.; Zhang, Y.F.; Wang, B.A.; Liu, R.P.

    2013-01-01

    Zirconium (Zr)-based bulk metallic glass possesses the highest potential as a structural material among metallic glasses. Although Zr-based bulk metallic glass exhibits extremely high strength, its potential application has been restricted by a number of issues, such as fragility, small size, difficult fabrication into different shapes and poisonous beryllium content, among others. In this paper, a Zr-based crystal alloy with comparable strength and higher plasticity than Zr-based bulk metallic glass is presented. The proposed Zr-based alloy has a tensile strength greater than 1600 MPa. That value is comparable to the 1500 MPa to 2000 MPa strength of Zr-based bulk metallic glasses (BMGs). The ductility in terms of elongation reached 6.2%; at the same time, the 1400 MPa tensile strength was retained. This phenomenon is not possible for Zr-based BMGs. XRD results show that the proposed ultrahigh-strength Zr-based crystal alloy has two-phase structures: an hcp-structured α phase and a bcc-structured β phase. The forged specimen exhibits a typical basket-weave microstructure, which is characterised by the interlaced plate α phase separated from the β phase matrix. Fine, short bar-shaped α phases precipitated along the original β grain boundary together with ultrafine dot-shaped α phases that presented inside the original β grain when the ageing temperature was between 500 °C and 525 °C. As the ageing temperature increased, the dot-shaped α phase grew into plate shapes, decreasing the material's strength and increasing its plasticity. The ultrafine dot-shaped and short bar-shaped α phases in the original β phase matrix are the main strengthening mechanisms of the ultrahigh-strength Zr-based crystal alloy.

  11. Unifying ecology and macroevolution with individual-based theory.

    Science.gov (United States)

    Rosindell, James; Harmon, Luke J; Etienne, Rampal S

    2015-05-01

    A contemporary goal in both ecology and evolutionary biology is to develop theory that transcends the boundary between the two disciplines, to understand phenomena that cannot be explained by either field in isolation. This is challenging because macroevolution typically uses lineage-based models, whereas ecology often focuses on individual organisms. Here, we develop a new parsimonious individual-based theory by adding mild selection to the neutral theory of biodiversity. We show that this model generates realistic phylogenies showing a slowdown in diversification and also improves on the ecological predictions of neutral theory by explaining the occurrence of very common species. Moreover, we find the distribution of individual fitness changes over time, with average fitness increasing at a pace that depends positively on community size. Consequently, large communities tend to produce fitter species than smaller communities. These findings have broad implications beyond biodiversity theory, potentially impacting, for example, invasion biology and paleontology. © 2015 The Authors. Ecology Letters published by John Wiley & Sons Ltd and CNRS.

  12. A Model of Statistics Performance Based on Achievement Goal Theory.

    Science.gov (United States)

    Bandalos, Deborah L.; Finney, Sara J.; Geske, Jenenne A.

    2003-01-01

    Tests a model of statistics performance based on achievement goal theory. Both learning and performance goals affected achievement indirectly through study strategies, self-efficacy, and test anxiety. Implications of these findings for teaching and learning statistics are discussed. (Contains 47 references, 3 tables, 3 figures, and 1 appendix.)…

  13. Toward an Instructionally Oriented Theory of Example-Based Learning

    Science.gov (United States)

    Renkl, Alexander

    2014-01-01

    Learning from examples is a very effective means of initial cognitive skill acquisition. There is an enormous body of research on the specifics of this learning method. This article presents an instructionally oriented theory of example-based learning that integrates theoretical assumptions and findings from three research areas: learning from…

  14. New MPPT algorithm based on hybrid dynamical theory

    KAUST Repository

    Elmetennani, Shahrazed

    2014-11-01

    This paper presents a new maximum power point tracking algorithm based on the hybrid dynamical theory. A multiceli converter has been considered as an adaptation stage for the photovoltaic chain. The proposed algorithm is a hybrid automata switching between eight different operating modes, which has been validated by simulation tests under different working conditions. © 2014 IEEE.

  15. New unified field theory based on the conformal group

    Energy Technology Data Exchange (ETDEWEB)

    Pessa, E [Rome Univ. (Italy). Ist. di Matematica

    1980-10-01

    Based on a six-dimensional generalization of Maxwell's equations, a new unified theory of the electromagnetic and gravitational field is developed. Additional space-time coordinates are interpreted only as mathematical tools in order to obtain a linear realization of the four-dimensional conformal group.

  16. Technical Note: Application of Decision Theory Based Criteria for ...

    African Journals Online (AJOL)

    Technical Note: Application of Decision Theory Based Criteria for Structural Appraisal of a Building during Construction. ... Nigerian Journal of Technology ... reliability of concrete in a structure during construction, a case study of laboratory block for College of Continuing Education, University of Port Harcourt, Rivers State.

  17. Mobile applications for weight management: theory-based content analysis.

    Science.gov (United States)

    Azar, Kristen M J; Lesser, Lenard I; Laing, Brian Y; Stephens, Janna; Aurora, Magi S; Burke, Lora E; Palaniappan, Latha P

    2013-11-01

    The use of smartphone applications (apps) to assist with weight management is increasingly prevalent, but the quality of these apps is not well characterized. The goal of the study was to evaluate diet/nutrition and anthropometric tracking apps based on incorporation of features consistent with theories of behavior change. A comparative, descriptive assessment was conducted of the top-rated free apps in the Health and Fitness category available in the iTunes App Store. Health and Fitness apps (N=200) were evaluated using predetermined inclusion/exclusion criteria and categorized based on commonality in functionality, features, and developer description. Four researchers then evaluated the two most popular apps in each category using two instruments: one based on traditional behavioral theory (score range: 0-100) and the other on the Fogg Behavioral Model (score range: 0-6). Data collection and analysis occurred in November 2012. Eligible apps (n=23) were divided into five categories: (1) diet tracking; (2) healthy cooking; (3) weight/anthropometric tracking; (4) grocery decision making; and (5) restaurant decision making. The mean behavioral theory score was 8.1 (SD=4.2); the mean persuasive technology score was 1.9 (SD=1.7). The top-rated app on both scales was Lose It! by Fitnow Inc. All apps received low overall scores for inclusion of behavioral theory-based strategies. © 2013 American Journal of Preventive Medicine.

  18. Applications of decision theory to test-based decision making

    NARCIS (Netherlands)

    van der Linden, Willem J.

    1987-01-01

    The use of Bayesian decision theory to solve problems in test-based decision making is discussed. Four basic decision problems are distinguished: (1) selection; (2) mastery; (3) placement; and (4) classification, the situation where each treatment has its own criterion. Each type of decision can be

  19. PhysarumSoft: An update based on rough set theory

    Science.gov (United States)

    Schumann, Andrew; Pancerz, Krzysztof

    2017-07-01

    PhysarumSoft is a software tool consisting of two modules developed for programming Physarum machines and simulating Physarum games, respectively. The paper briefly discusses what has been added since the last version released in 2015. New elements in both modules are based on rough set theory. Rough sets are used to model behaviour of Physarum machines and to describe strategy games.

  20. New MPPT algorithm based on hybrid dynamical theory

    KAUST Repository

    Elmetennani, Shahrazed; Laleg-Kirati, Taous-Meriem; Benmansour, K.; Boucherit, M. S.; Tadjine, M.

    2014-01-01

    This paper presents a new maximum power point tracking algorithm based on the hybrid dynamical theory. A multiceli converter has been considered as an adaptation stage for the photovoltaic chain. The proposed algorithm is a hybrid automata switching between eight different operating modes, which has been validated by simulation tests under different working conditions. © 2014 IEEE.

  1. Unifying ecology and macroevolution with individual-based theory

    NARCIS (Netherlands)

    Rosindell, James; Harmon, Luke J.; Etienne, Rampal S.

    A contemporary goal in both ecology and evolutionary biology is to develop theory that transcends the boundary between the two disciplines, to understand phenomena that cannot be explained by either field in isolation. This is challenging because macroevolution typically uses lineage-based models,

  2. The Mediating Effect of Self-Efficacy in the Connections between Strength-Based Parenting, Happiness and Psychological Distress in Teens

    OpenAIRE

    Loton, Daniel J.; Waters, Lea E.

    2017-01-01

    Preliminary studies of strength-based parenting (SBP), a style of parenting that seeks to build strengths knowledge and strengths use in one’s child, have reported benefits such as higher life satisfaction, subjective wellbeing, and positive emotions together with lower stress in children and teens. Two proximal mediators conveying these effects have been identified: teen’s own use of strengths and strength-based coping, along with a small moderating effect of growth mindsets relating to stre...

  3. Mapping site-based construction workers’ motivation: Expectancy theory approach

    Directory of Open Access Journals (Sweden)

    Parviz Ghoddousi

    2014-03-01

    Full Text Available The aim of this study is to apply a recently proposed model of motivation based on expectancy theory to site-based workers in the construction context and confirm the validity of this model for the construction industry. The study drew upon data from 194 site-based construction workers in Iran to test the proposed model of motivation. To this end, the structural equation modelling (SEM approach based on the confirmatory factor analysis (CFA technique was deployed. The study reveals that the proposed model of expectancy theory incorporating five indicators (i.e. intrinsic instrumentality, extrinsic instrumentality, intrinsic valence, extrinsic valence and expectancy is able to map the process of construction workers’ motivation. Nonetheless, the findings posit that intrinsic indicators could be more effective than extrinsic ones. This proffers the necessity of construction managers placing further focus on intrinsic motivators to motivate workers. 

  4. Mapping site-based construction workers’ motivation: Expectancy theory approach

    Directory of Open Access Journals (Sweden)

    Parviz Ghoddousi

    2014-03-01

    Full Text Available The aim of this study is to apply a recently proposed model of motivation based on expectancy theory to site-based workers in the construction context and confirm the validity of this model for the construction industry. The study drew upon data from 194 site-based construction workers in Iran to test the proposed model of motivation. To this end, the structural equation modelling (SEM approach based on the confirmatory factor analysis (CFA technique was deployed. The study reveals that the proposed model of expectancy theory incorporating five indicators (i.e. intrinsic instrumentality, extrinsic instrumentality, intrinsic valence, extrinsic valence and expectancy is able to map the process of construction workers’ motivation. Nonetheless, the findings posit that intrinsic indicators could be more effective than extrinsic ones. This proffers the necessity of construction managers placing further focus on intrinsic motivators to motivate workers.

  5. Tumour chemotherapy strategy based on impulse control theory.

    Science.gov (United States)

    Ren, Hai-Peng; Yang, Yan; Baptista, Murilo S; Grebogi, Celso

    2017-03-06

    Chemotherapy is a widely accepted method for tumour treatment. A medical doctor usually treats patients periodically with an amount of drug according to empirical medicine guides. From the point of view of cybernetics, this procedure is an impulse control system, where the amount and frequency of drug used can be determined analytically using the impulse control theory. In this paper, the stability of a chemotherapy treatment of a tumour is analysed applying the impulse control theory. The globally stable condition for prescription of a periodic oscillatory chemotherapeutic agent is derived. The permanence of the solution of the treatment process is verified using the Lyapunov function and the comparison theorem. Finally, we provide the values for the strength and the time interval that the chemotherapeutic agent needs to be applied such that the proposed impulse chemotherapy can eliminate the tumour cells and preserve the immune cells. The results given in the paper provide an analytical formula to guide medical doctors to choose the theoretical minimum amount of drug to treat the cancer and prevent harming the patients because of over-treating.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).

  6. Evidence for an expectancy-based theory of avoidance behaviour.

    Science.gov (United States)

    Declercq, Mieke; De Houwer, Jan; Baeyens, Frank

    2008-01-01

    In most studies on avoidance learning, participants receive an aversive unconditioned stimulus after a warning signal is presented, unless the participant performs a particular response. Lovibond (2006) recently proposed a cognitive theory of avoidance learning, according to which avoidance behaviour is a function of both Pavlovian and instrumental conditioning. In line with this theory, we found that avoidance behaviour was based on an integration of acquired knowledge about, on the one hand, the relation between stimuli and, on the other hand, the relation between behaviour and stimuli.

  7. Theory-based Bayesian models of inductive learning and reasoning.

    Science.gov (United States)

    Tenenbaum, Joshua B; Griffiths, Thomas L; Kemp, Charles

    2006-07-01

    Inductive inference allows humans to make powerful generalizations from sparse data when learning about word meanings, unobserved properties, causal relationships, and many other aspects of the world. Traditional accounts of induction emphasize either the power of statistical learning, or the importance of strong constraints from structured domain knowledge, intuitive theories or schemas. We argue that both components are necessary to explain the nature, use and acquisition of human knowledge, and we introduce a theory-based Bayesian framework for modeling inductive learning and reasoning as statistical inferences over structured knowledge representations.

  8. Person-based differences in pay reactions: A compensation-activation theory and integrative conceptual review.

    Science.gov (United States)

    Fulmer, Ingrid Smithey; Shaw, Jason D

    2018-06-07

    Compensation research has focused traditionally on how pay design characteristics (e.g., pay level, individual or group incentives) relate to average employee outcomes and, in toto, on how these outcomes affect organizational performance. Recently, scholars have begun to pay more attention to how individuals vary in the strength of their reactions to pay. Empirical research in several disciplines examines how the interplay of pay systems and person-based characteristics (psychological individual differences, demographics, and relative performance or position in a group) relate to important work-related outcomes. We develop a compensation-activation theory that frames compensation design characteristics as workplace "situations" providing cues that activate individuals' corresponding fundamental social motives made salient due to chronic or transient person-based characteristics. Where activation occurs, stronger-than-average responses to the compensation "situation" are expected. Using the theory as a lens, we synthesize and reinterpret existing research on person-based reactions to pay characteristics, including sorting, incentive/motivational effects, and effects on collective pay system reactions and unit/organizational outcomes. We conclude with a research agenda aimed at refining compensation-activation theory and advancing the study of compensation as it affects individual and organizational outcomes. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  9. A Game Theory Based Solution for Security Challenges in CRNs

    Science.gov (United States)

    Poonam; Nagpal, Chander Kumar

    2018-03-01

    Cognitive radio networks (CRNs) are being envisioned to drive the next generation Ad hoc wireless networks due to their ability to provide communications resilience in continuously changing environments through the use of dynamic spectrum access. Conventionally CRNs are dependent upon the information gathered by other secondary users to ensure the accuracy of spectrum sensing making them vulnerable to security attacks leading to the need of security mechanisms like cryptography and trust. However, a typical cryptography based solution is not a viable security solution for CRNs owing to their limited resources. Effectiveness of trust based approaches has always been, in question, due to credibility of secondary trust resources. Game theory with its ability to optimize in an environment of conflicting interests can be quite a suitable tool to manage an ad hoc network in the presence of autonomous selfish/malevolent/malicious and attacker nodes. The literature contains several theoretical proposals for augmenting game theory in the ad hoc networks without explicit/detailed implementation. This paper implements a game theory based solution in MATLAB-2015 to secure the CRN environment and compares the obtained results with the traditional approaches of trust and cryptography. The simulation result indicates that as the time progresses the game theory performs much better with higher throughput, lower jitter and better identification of selfish/malicious nodes.

  10. Extending Theory-Based Quantitative Predictions to New Health Behaviors.

    Science.gov (United States)

    Brick, Leslie Ann D; Velicer, Wayne F; Redding, Colleen A; Rossi, Joseph S; Prochaska, James O

    2016-04-01

    Traditional null hypothesis significance testing suffers many limitations and is poorly adapted to theory testing. A proposed alternative approach, called Testing Theory-based Quantitative Predictions, uses effect size estimates and confidence intervals to directly test predictions based on theory. This paper replicates findings from previous smoking studies and extends the approach to diet and sun protection behaviors using baseline data from a Transtheoretical Model behavioral intervention (N = 5407). Effect size predictions were developed using two methods: (1) applying refined effect size estimates from previous smoking research or (2) using predictions developed by an expert panel. Thirteen of 15 predictions were confirmed for smoking. For diet, 7 of 14 predictions were confirmed using smoking predictions and 6 of 16 using expert panel predictions. For sun protection, 3 of 11 predictions were confirmed using smoking predictions and 5 of 19 using expert panel predictions. Expert panel predictions and smoking-based predictions poorly predicted effect sizes for diet and sun protection constructs. Future studies should aim to use previous empirical data to generate predictions whenever possible. The best results occur when there have been several iterations of predictions for a behavior, such as with smoking, demonstrating that expected values begin to converge on the population effect size. Overall, the study supports necessity in strengthening and revising theory with empirical data.

  11. Case studies of extended model-based flood forecasting: prediction of dike strength and flood impacts

    Science.gov (United States)

    Stuparu, Dana; Bachmann, Daniel; Bogaard, Tom; Twigt, Daniel; Verkade, Jan; de Bruijn, Karin; de Leeuw, Annemargreet

    2017-04-01

    Flood forecasts, warning and emergency response are important components in flood risk management. Most flood forecasting systems use models to translate weather predictions to forecasted discharges or water levels. However, this information is often not sufficient for real time decisions. A sound understanding of the reliability of embankments and flood dynamics is needed to react timely and reduce the negative effects of the flood. Where are the weak points in the dike system? When, how much and where the water will flow? When and where is the greatest impact expected? Model-based flood impact forecasting tries to answer these questions by adding new dimensions to the existing forecasting systems by providing forecasted information about: (a) the dike strength during the event (reliability), (b) the flood extent in case of an overflow or a dike failure (flood spread) and (c) the assets at risk (impacts). This work presents three study-cases in which such a set-up is applied. Special features are highlighted. Forecasting of dike strength. The first study-case focusses on the forecast of dike strength in the Netherlands for the river Rhine branches Waal, Nederrijn and IJssel. A so-called reliability transformation is used to translate the predicted water levels at selected dike sections into failure probabilities during a flood event. The reliability of a dike section is defined by fragility curves - a summary of the dike strength conditional to the water level. The reliability information enhances the emergency management and inspections of embankments. Ensemble forecasting. The second study-case shows the setup of a flood impact forecasting system in Dumfries, Scotland. The existing forecasting system is extended with a 2D flood spreading model in combination with the Delft-FIAT impact model. Ensemble forecasts are used to make use of the uncertainty in the precipitation forecasts, which is useful to quantify the certainty of a forecasted flood event. From global

  12. Coulomb repulsion and correlation strength in LaFeAsO from density functional and dynamical mean-field theories

    Czech Academy of Sciences Publication Activity Database

    Anisimov, V.I.; Korotin, D. M.; Korotin, M. A.; Kozhevnikov, A, V.; Kuneš, Jan; Shorikov, A.O.; Skornyakov, S.L.; Streltsov, S. V.

    2009-01-01

    Roč. 21, č. 7 (2009), 075602/1-075602/7 ISSN 0953-8984 Institutional research plan: CEZ:AV0Z10100521 Keywords : iron pnictide * electronic correlations * dynamical mean-field theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.964, year: 2009

  13. The Effect of Alkaline Activator Ratio on the Compressive Strength of Fly Ash-Based Geopolymer Paste

    Science.gov (United States)

    Lăzărescu, A. V.; Szilagyi, H.; Baeră, C.; Ioani, A.

    2017-06-01

    Alkaline activation of fly ash is a particular procedure in which ash resulting from a power plant combined with a specific alkaline activator creates a solid material when dried at a certain temperature. In order to obtain desirable compressive strengths, the mix design of fly ash based geopolymer pastes should be explored comprehensively. To determine the preliminary compressive strength for fly ash based geopolymer paste using Romanian material source, various ratios of Na2SiO3 solution/ NaOH solution were produced, keeping the fly ash/alkaline activator ratio constant. All the mixes were then cured at 70 °C for 24 hours and tested at 2 and 7 days, respectively. The aim of this paper is to present the preliminary compressive strength results for producing fly ash based geopolymer paste using Romanian material sources, the effect of alkaline activators ratio on the compressive strength and studying the directions for future research.

  14. Promoting physical activity among children and adolescents: the strengths and limitations of school-based approaches.

    Science.gov (United States)

    Booth, Michael; Okely, Anthony

    2005-04-01

    Paediatric overweight and obesity is recognised as one of Australia's most significant health problems and effective approaches to increasing physical activity and reducing energy consumption are being sought urgently. Every potential approach and setting should be subjected to critical review in an attempt to maximise the impact of policy and program initiatives. This paper identifies the strengths and limitations of schools as a setting for promoting physical activity. The strengths are: most children and adolescents attend school; most young people are likely to see teachers as credible sources of information; schools provide access to the facilities, infrastructure and support required for physical activity; and schools are the workplace of skilled educators. Potential limitations are: those students who like school the least are the most likely to engage in health-compromising behaviours and the least likely to be influenced by school-based programs; there are about 20 more hours per week available for physical activity outside schools hours than during school hours; enormous demands are already being made on schools; many primary school teachers have low levels of perceived competence in teaching physical education and fundamental movement skills; and opportunities for being active at school may not be consistent with how and when students prefer to be active.

  15. Tensile strengths of polyamide based 3D printed polymers in liquid nitrogen

    International Nuclear Information System (INIS)

    Cruz, P; Shoemake, E D; Adam, P; Leachman, J

    2015-01-01

    Advances in additive manufacturing technology have made 3D printing a viable solution for many industries, allowing for the manufacture of designs that could not be made through traditional subtractive methods. Applicability of additive manufacturing in cryogenic applications is hindered, however, by a lack of accurate material properties information. Nylon is available for printing using fused deposition modeling (FDM) and selective laser sintering (SLS). We selected 5 SLS (DuraForm® EX, DuraForm® HST, DuraForm® PA, PA 640-GSL, and PA 840-GSL) and 2 FDM (Nylon 12, ULTEM) nylon variants based on the bulk material properties and printed properties at room temperature. Tensile tests were performed on five samples of each material while immersed in liquid nitrogen at approximately 77 Kelvin. Samples were tested in XY and, where available, Z printing directions to determine influence on material properties. Results show typical SLS and FDM nylon ultimate strength retention at 77 K, when compared to (extruded or molded) nylon ultimate strength. (paper)

  16. Changes in muscle strength in elderly women after proprioceptive neuromuscular facilitation based training

    Directory of Open Access Journals (Sweden)

    Edivã Bernardo da Silva

    Full Text Available Introduction Proprioceptive neuromuscular facilitation (PNF can be used to improve the quality of life of both healthy and diseased subjects, including the elderly, who suffer muscular weakness due to aging, leading to an impairment in functional capacity. Objective Verify the effectiveness of PNF as a tool for functional conditioning. Materials and methods We evaluated a total of ten elderly women aged 60–70 years, clinically healthy and physically active. They had the force of motion of hip flexion with knee extension analyzed by an analog dynamometer. They were then randomly and equally divided into experimental (EG and control group (CG. The GC was instructed to continue with their normal activities while the GE held 15 training sessions in the lower limb (LL based on the diagonal D1 and D2. Finally, a new collection wrench the two groups was performed and the data compared. Results There was a significant increase in the average strength of GE, on the order of 31% (p 0.05. Discussion : The results confirm that the FNP through initial work of readjustment and proprioceptive neuromuscular activation, and after that, conditioning of the muscle fibers (mainly resistive is capable of amplifying the force developed by the muscle. Conclusion The PNF was effective as training to gain muscle strength, should be better analyzed as a tool fitness, not to cause health risks, have low cost and easy application.

  17. Microstructure-based assessment of creep rupture strength in 9Cr steels

    International Nuclear Information System (INIS)

    Spigarelli, S.

    2013-01-01

    A microstructure-based model to assess the long-term creep strength in 9Cr steels is proposed. The model takes into account a number of different key issues, including the presence and evolution of the most important families of precipitates (M 23 C 6 , MX, Laves and Z phases), the subgrain recovery process, the different strengthening mechanisms (solid solution strengthening and particle strengthening), and is able to give realistic values of the long-term creep strength in P9, P91 and P911 steels. If properly tuned to describe the mid/long-term precipitation of the Z-phase, and the concurrent dissolution of MX precipitates, the model can also predict the sigmoidal behaviour which leads to the early rupture of single heats of P91 steel. Highlights: ► Creep response at 600 °C of 9% Cr steels. ► Important effect of the different families of precipitates. ► The effect is described by introducing the grain size term in a previously developed model. ► Degradation of particle strengthening effect is considered by calculating the coarsening of the particles.

  18. Push-out bond strength of different tricalcium silicate-based filling materials to root dentin

    Directory of Open Access Journals (Sweden)

    Jorge Henrique Stefaneli Marques

    2018-03-01

    Full Text Available Abstract: The aim of this study was to evaluate the bond strength of different triccalcium silicate cements to retrograde cavity using a push out test. Thirty maxillary central incisors were shaped using #80 hand files and sectioned transversally. Root slices were obtained from the apical 4 mm after eliminating the apical extremity. The specimens were embedded in acrylic resin and positioned at 45° to the horizontal plane for preparation of root-end cavities with a diamond ultrasonic retrotip. The samples were divided into three groups according to the root-end filling material (n = 10: MTA Angelus, ProRoot MTA and Biodentine. A gutta-percha cone (#80 was tugged-back at the limit between the canal and the root-end cavity. The root-end cavity was filled and the gutta-percha cone was removed after complete setting of the materials. The specimens were placed in an Instron machine with the root-end filling turned downwards. The push-out shaft was inserted in the space previously occupied by the gutta-percha cone and push out testing was performed at a crosshead speed of 1.0 mm/min. There was no statistically significant difference in resistance to push out by the materials tested (p > 0.01. MTA Angelus and ProRoot MTA showed predominantly mixed failure while Biodentine exhibited mixed and cohesive failures. The tricalcium silicate-based root-end filling materials showed similar bond strength retrograde cavity.

  19. Push-out bond strength of different tricalcium silicate-based filling materials to root dentin.

    Science.gov (United States)

    Stefaneli Marques, Jorge Henrique; Silva-Sousa, Yara Teresinha Corrêa; Rached-Júnior, Fuad Jacob Abi; Macedo, Luciana Martins Domingues de; Mazzi-Chaves, Jardel Francisco; Camilleri, Josette; Sousa-Neto, Manoel Damião

    2018-03-08

    The aim of this study was to evaluate the bond strength of different triccalcium silicate cements to retrograde cavity using a push out test. Thirty maxillary central incisors were shaped using #80 hand files and sectioned transversally. Root slices were obtained from the apical 4 mm after eliminating the apical extremity. The specimens were embedded in acrylic resin and positioned at 45° to the horizontal plane for preparation of root-end cavities with a diamond ultrasonic retrotip. The samples were divided into three groups according to the root-end filling material (n = 10): MTA Angelus, ProRoot MTA and Biodentine. A gutta-percha cone (#80) was tugged-back at the limit between the canal and the root-end cavity. The root-end cavity was filled and the gutta-percha cone was removed after complete setting of the materials. The specimens were placed in an Instron machine with the root-end filling turned downwards. The push-out shaft was inserted in the space previously occupied by the gutta-percha cone and push out testing was performed at a crosshead speed of 1.0 mm/min. There was no statistically significant difference in resistance to push out by the materials tested (p > 0.01). MTA Angelus and ProRoot MTA showed predominantly mixed failure while Biodentine exhibited mixed and cohesive failures. The tricalcium silicate-based root-end filling materials showed similar bond strength retrograde cavity.

  20. An integrative, experience-based theory of attentional control.

    Science.gov (United States)

    Wilder, Matthew H; Mozer, Michael C; Wickens, Christopher D

    2011-02-09

    Although diverse, theories of visual attention generally share the notion that attention is controlled by some combination of three distinct strategies: (1) exogenous cuing from locally contrasting primitive visual features, such as abrupt onsets or color singletons (e.g., L. Itti, C. Koch, & E. Neiber, 1998), (2) endogenous gain modulation of exogenous activations, used to guide attention to task-relevant features (e.g., V. Navalpakkam & L. Itti, 2007; J. Wolfe, 1994, 2007), and (3) endogenous prediction of likely locations of interest, based on task and scene gist (e.g., A. Torralba, A. Oliva, M. Castelhano, & J. Henderson, 2006). However, little work has been done to synthesize these disparate theories. In this work, we propose a unifying conceptualization in which attention is controlled along two dimensions: the degree of task focus and the contextual scale of operation. Previously proposed strategies-and their combinations-can be viewed as instances of this one mechanism. Thus, this theory serves not as a replacement for existing models but as a means of bringing them into a coherent framework. We present an implementation of this theory and demonstrate its applicability to a wide range of attentional phenomena. The model accounts for key results in visual search with synthetic images and makes reasonable predictions for human eye movements in search tasks involving real-world images. In addition, the theory offers an unusual perspective on attention that places a fundamental emphasis on the role of experience and task-related knowledge.

  1. Theory-Based Stakeholder Evaluation – applied. Competing Stakeholder Theories in the Quality Management of Primary Education

    DEFF Research Database (Denmark)

    Hansen, Morten Balle; Heilesen, J. B.

    In the broader context of evaluation design, this paper examines and compares pros and cons of a theory-based approach to evaluation (TBE) with the Theory-Based Stakeholder evaluation (TSE) model, introduced by Morten Balle Hansen and Evert Vedung (Hansen and Vedung 2010). While most approaches...... to TBE construct one unitary theory of the program (Coryn et al. 2011), the TSE-model emphasizes the importance of keeping theories of diverse stakeholders apart. This paper applies the TSE-model to an evaluation study conducted by the Danish Evaluation Institute (EVA) of the Danish system of quality......-model, as an alternative to traditional program theory evaluation....

  2. Hamiltonian theories quantization based on a probability operator

    International Nuclear Information System (INIS)

    Entral'go, E.E.

    1986-01-01

    The quantization method with a linear reflection of classical coordinate-momentum-time functions Λ(q,p,t) at quantum operators in a space of quantum states ψ, is considered. The probability operator satisfies a system of equations representing the principles of dynamical and canonical correspondences between the classical and quantum theories. The quantization based on a probability operator leads to a quantum theory with a nonnegative joint coordinate-momentum distribution function for any state ψ. The main consequences of quantum mechanics with a probability operator are discussed in comparison with the generally accepted quantum and classical theories. It is shown that a probability operator leads to an appearance of some new notions called ''subquantum'' ones. Hence the quantum theory with a probability operator does not pretend to any complete description of physical reality in terms of classical variables and by this reason contains no problems like Einstein-Podolsky-Rosen paradox. The results of some concrete problems are given: a free particle, a harmonic oscillator, an electron in the Coulomb field. These results give hope on the possibility of an experimental verification of the quantization based on a probability operator

  3. Commitment-based action: Rational choice theory and contrapreferential choice

    Directory of Open Access Journals (Sweden)

    Radovanović Bojana

    2014-01-01

    Full Text Available This paper focuses on Sen’s concept of contrapreferential choice. Sen has developed this concept in order to overcome weaknesses of the rational choice theory. According to rational choice theory a decision-maker can be always seen as someone who maximises utility, and each choice he makes as the one that brings to him the highest level of personal wellbeing. Sen argues that in some situations we chose alternatives that bring us lower level of wellbeing than we could achieve if we had chosen some other alternative available to us. This happens when we base our decisions on moral principles, when we act out of duty. Sen calls such action a commitment-based action. When we act out of commitment we actually neglect our preferences and thus we make a contrapreferential choice, as Sen argues. This paper shows that, contrary to Sen, a commitment-based action can be explained within the framework of rational choice theory. However, when each choice we make can be explained within the framework of rational choice theory, when in everything we do maximisation principle can be loaded, then the variety of our motives and traits is lost, and the explanatory power of the rational choice theory is questionable. [Projekat Ministarstva nauke Republike Srbije, br. 47009: Evropske integracije i društveno-ekonomske promene privrede Srbije na putu ka EU i br. 179015: Izazovi i perspektive strukturnih promena u Srbiji: Strateški pravci ekonomskog razvoja i usklađivanje sa zahtevima EU

  4. National surveys of radiofrequency field strengths from radio base stations in Africa

    Science.gov (United States)

    Joyner, Ken H.; Van Wyk, Marthinus J.; Rowley, Jack T.

    2014-01-01

    The authors analysed almost 260 000 measurement points from surveys of radiofrequency (RF) field strengths near radio base stations in seven African countries over two time frames from 2001 to 2003 and 2006 to 2012. The results of the national surveys were compared, chronological trends investigated and potential exposures compared by technology and with frequency modulation (FM) radio. The key findings from thes data are that irrespective of country, the year and mobile technology, RF fields at a ground level were only a small fraction of the international human RF exposure recommendations. Importantly, there has been no significant increase in typical measured levels since the introduction of 3G services. The mean levels in these African countries are similar to the reported levels for countries of Asia, Europe and North America using similar mobile technologies. The median level for the FM services in South Africa was comparable to the individual but generally lower than the combined mobile services. PMID:24044904

  5. A flexible environmental reuse/recycle policy based on economic strength.

    Science.gov (United States)

    Tsiliyannis, C A

    2007-01-01

    Environmental policies based on fixed recycling rates may lead to increased environmental impacts (e.g., landfilled wastes) during economic expansion. A rate policy is proposed, which is adjusted according to the overall strength or weakness of the economy, as reflected by overall packaging demand and consumption, production and imports-exports. During economic expansion featuring rising consumption, production or exports, the proposed flexible policy suggests a higher reuse/recycle rate. During economic slowdown a lower rate results in lower impacts. The flexible target rates are determined in terms of annual data, including consumption, imports-exports and production. Higher environmental gains can be achieved at lower cost if the flexible policy is applied to widely consumed packaging products and materials associated with low rates, or if cleaner recycling technology is adopted.

  6. National surveys of radiofrequency field strengths from radio base stations in Africa

    International Nuclear Information System (INIS)

    Joyner, K. H.; Van Wyk, M. J.; Rowley, J. T.

    2014-01-01

    The authors analysed almost 260 000 measurement points from surveys of radiofrequency (RF) field strengths near radio base stations in seven African countries over two time frames from 2001 to 2003 and 2006 to 2012. The results of the national surveys were compared, chronological trends investigated and potential exposures compared by technology and with frequency modulation (FM) radio. The key findings from these data are that irrespective of country, the year and mobile technology, RF fields at a ground level were only a small fraction of the international human RF exposure recommendations. Importantly, there has been no significant increase in typical measured levels since the introduction of 3G services. The mean levels in these African countries are similar to the reported levels for countries of Asia, Europe and North America using similar mobile technologies. The median level for the FM services in South Africa was comparable to the individual but generally lower than the combined mobile services. (authors)

  7. High tensile strength fly ash based geopolymer composite using copper coated micro steel fiber

    DEFF Research Database (Denmark)

    Ranjbar, Navid; Mehrali, Mehdi; Mehrali, Mohammad

    2016-01-01

    -matrix interaction. In this present study, effects of micro steel fibers (MSF) incorporation on mechanical properties of fly ash based geopolymer was investigated at different volume ratio of matrix. Various properties of the composite were compared in terms of fresh state by flow measurement and hardened state......As a ceramic-like material, geopolymers show a high quasi-brittle behavior and relatively low fracture energy. To overcome this, the addition of fibers to a brittle matrix is a well-known method to improve the flexural strength. Moreover, the success of the reinforcements is dependent on the fiber...... by variation of shrinkage over time to assess performance of the composites subjected to flexural and compressive load. The fiber-matrix interface, fiber surface and toughening mechanisms were assessed using field emission scan electron microscopy (FESEM) and atomic force microscopy (AFM) through a period...

  8. Microshear bond strength of preheated silorane- and methacrylate-based composite resins to dentin.

    Science.gov (United States)

    Demirbuga, Sezer; Ucar, Faruk Izzet; Cayabatmaz, Muhammed; Zorba, Yahya Orcun; Cantekin, Kenan; Topçuoğlu, Hüseyin Sinan; Kilinc, Halil Ibrahim

    2016-01-01

    The aim of this study was to investigate the effect of preheating on microshear bond strength (MSBS) of silorane and methacrylate-based composite resins to human dentin. The teeth were randomly divided into three main groups: (1) composite resins were heated upto 68 °C; (2) cooled to 4 °C; and (3) control [room temperature (RT)]. Each group was then randomly subdivided into four subgroups according to adhesive system used [Solobond M (Voco), All Bond SE (Bisco), Clearfil SE Bond (CSE) (Kuraray), Silorane adhesive system (SAS) (3M ESPE)]. Resin composite cylinders were formed (0.9 mm diameter × 0.7 mm length) and MSBS of each specimen was tested. The preheated groups exhibited the highest MSBS (p composite resins may be an alternative way to increase the MSBS of composites on dentin. © Wiley Periodicals, Inc.

  9. Feature Matching for SAR and Optical Images Based on Gaussian-Gamma-shaped Edge Strength Map

    Directory of Open Access Journals (Sweden)

    CHEN Min

    2016-03-01

    Full Text Available A matching method for SAR and optical images, robust to pixel noise and nonlinear grayscale differences, is presented. Firstly, a rough correction to eliminate rotation and scale change between images is performed. Secondly, features robust to speckle noise of SAR image are detected by improving the original phase congruency based method. Then, feature descriptors are constructed on the Gaussian-Gamma-shaped edge strength map according to the histogram of oriented gradient pattern. Finally, descriptor similarity and geometrical relationship are combined to constrain the matching processing.The experimental results demonstrate that the proposed method provides significant improvement in correct matches number and image registration accuracy compared with other traditional methods.

  10. A novel aluminum based nanocomposite with high strength and good ductility

    Energy Technology Data Exchange (ETDEWEB)

    Ramezanalizadeh, Hossein, E-mail: hralizadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Emamy, Masoud [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Shokouhimehr, Mohammadreza [School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul (Korea, Republic of)

    2015-11-15

    Aluminum based nanocomposite containing nano-sized Al{sub 3}Mg{sub 2} reinforcing was fabricated via mechanical milling followed by hot extrusion techniques. For this, Al and Al{sub 3}Mg{sub 2} powders were mixed mechanically and milled at different times (0, 2, 5, 7, 10, 15 and 20 h) to achieve Al–10 wt.% Al{sub 3}Mg{sub 2} composite powders. Hot extrusion of cold pressed powders was done at 400 °C with extrusion ratio of 6:1. Microstructures of the powders and consolidated materials were studied using transmission electron microscopy, scanning electron microscope and X-ray diffraction. Fracture surfaces were also investigated by scanning electron microscopy equipped with EDS analyzer. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. In addition, the fabricated composites exhibited homogeneous distribution and less agglomerations of the n-Al{sub 3}Mg{sub 2} with increasing milling time. The mechanical behavior of these nanocomposites was investigated by hardness and tensile tests, which revealed it has four times the strength of a conventional Al along with good ductility. It was found that the ultimate tensile strength (UTS) and elongation of the nanocomposites were significantly improved with increases in milling time up to 15 h. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-Al{sub 3}Mg{sub 2}. Fracture surfaces showed that the interfacial bonding between Al and Al{sub 3}Mg{sub 2} could be improved with increasing in milling time. Also HRTEM results from interface showed that a metallurgical clean interface and intimate contact between matrix and second phase. By extending the milling process up to 20 h, there was no significant improvement in mechanical behavior of materials, due to the completion of milling process and dynamic and static recovery of composite at higher milling times. - Highlights: • A novel aluminum-based

  11. Multispectral iris recognition based on group selection and game theory

    Science.gov (United States)

    Ahmad, Foysal; Roy, Kaushik

    2017-05-01

    A commercially available iris recognition system uses only a narrow band of the near infrared spectrum (700-900 nm) while iris images captured in the wide range of 405 nm to 1550 nm offer potential benefits to enhance recognition performance of an iris biometric system. The novelty of this research is that a group selection algorithm based on coalition game theory is explored to select the best patch subsets. In this algorithm, patches are divided into several groups based on their maximum contribution in different groups. Shapley values are used to evaluate the contribution of patches in different groups. Results show that this group selection based iris recognition

  12. The Strength Compass

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    In the Ph.D-project ͚Strengths-based Learning - Children͛s character strengths as a means to their learning potential͛ 750 Danish children have assessed ͚The Strength Compass͛ in order to identify their strengths and to create awareness of strengths. This was followed by a strengths......-based intervention program in order to explore the strengths. Finally different methods to apply the strength in everyday life at school were applied. The paper presentation will show the results for strengths display for children aged 6-16 in different categories: Different age groups: Are the same strengths...... present in both small children and youths? Gender: Do the results show differences between the two genders? Danish as a mother- tongue language: Do the results show any differences in the strengths display when considering different language and cultural backgrounds? Children with Special Needs: Do...

  13. Effect of repair resin type and surface treatment on the repair strength of polyamide denture base resin.

    Science.gov (United States)

    Gundogdu, Mustafa; Yanikoglu, Nuran; Bayindir, Funda; Ciftci, Hilal

    2015-01-01

    The purpose of the present study was to evaluate the effects of different repair resins and surface treatments on the repair strength of a polyamide denture base material. Polyamide resin specimens were prepared and divided into nine groups according to the surface treatments and repair materials. The flexural strengths were measured with a 3-point bending test. Data were analyzed with a 2-way analysis of variance, and the post-hoc Tukey test (α=0.05). The effects of the surface treatments on the surface of the polyamide resin were examined using scanning electron microscopy. The repair resins and surface treatments significantly affected the repair strength of the polyamide denture base material (p0.05). The flexural strength of the specimens repaired with the polyamide resin was significantly higher than that of those repaired with the heat-polymerized and autopolymerizing acrylic resins.

  14. Network-based landscape of research strengths of universities in Mainland China

    Science.gov (United States)

    Liu, Zihua; Xiao, Qin; Zhan, Qian; Gu, Changgui; Yang, Huijie

    2017-07-01

    A landscape of a complex system presents a quantitative measure of its global state. The profile of research strength in Mainland China is investigated in detail, by which we illustrate a complex network based framework to extract a landscape from detailed records. First, a measure analogous to the Jaccard similarity is proposed to calculate from the presided funds similarities between the top-ranked universities. The neighbor threshold method is employed to reconstruct the similarity network of the universities. Second, the network is divided into communities. In each community the node with the largest degree and the smallest average shortest path length is taken as the representative of the community, called central node. The node bridging each pair of communities is defined to be a boundary. The central nodes and boundaries cooperatively give us a picture of the research strength landscape. Third, the evolutionary behavior is monitored by the fission and fusion probability matrices, elements of which are the percentage of a community at present time that joins into every community at the next time, and the percentage of a community at next time that comes from every present community, respectively. The landscapes in three successive 4-year durations are identified. It was found that some types of universities, such as the medicine&pharmacy and the finance&economy, conserve in single communities in the more than ten years, respectively. The agriculture&forest universities tend to cluster into one community. Meanwhile the engineering type distributes in different communities and tends to mix with the comprehension type. This framework can be used straightforwardly to analyze temporal networks. It provides also a new network-based method for multivariate time series analysis.

  15. A Rolling Element Bearing Fault Diagnosis Approach Based on Multifractal Theory and Gray Relation Theory.

    Science.gov (United States)

    Li, Jingchao; Cao, Yunpeng; Ying, Yulong; Li, Shuying

    2016-01-01

    Bearing failure is one of the dominant causes of failure and breakdowns in rotating machinery, leading to huge economic loss. Aiming at the nonstationary and nonlinear characteristics of bearing vibration signals as well as the complexity of condition-indicating information distribution in the signals, a novel rolling element bearing fault diagnosis method based on multifractal theory and gray relation theory was proposed in the paper. Firstly, a generalized multifractal dimension algorithm was developed to extract the characteristic vectors of fault features from the bearing vibration signals, which can offer more meaningful and distinguishing information reflecting different bearing health status in comparison with conventional single fractal dimension. After feature extraction by multifractal dimensions, an adaptive gray relation algorithm was applied to implement an automated bearing fault pattern recognition. The experimental results show that the proposed method can identify various bearing fault types as well as severities effectively and accurately.

  16. Intelligent Security IT System for Detecting Intruders Based on Received Signal Strength Indicators

    Directory of Open Access Journals (Sweden)

    Yunsick Sung

    2016-10-01

    Full Text Available Given that entropy-based IT technology has been applied in homes, office buildings and elsewhere for IT security systems, diverse kinds of intelligent services are currently provided. In particular, IT security systems have become more robust and varied. However, access control systems still depend on tags held by building entrants. Since tags can be obtained by intruders, an approach to counter the disadvantages of tags is required. For example, it is possible to track the movement of tags in intelligent buildings in order to detect intruders. Therefore, each tag owner can be judged by analyzing the movements of their tags. This paper proposes a security approach based on the received signal strength indicators (RSSIs of beacon-based tags to detect intruders. The normal RSSI patterns of moving entrants are obtained and analyzed. Intruders can be detected when abnormal RSSIs are measured in comparison to normal RSSI patterns. In the experiments, one normal and one abnormal scenario are defined for collecting the RSSIs of a Bluetooth-based beacon in order to validate the proposed method. When the RSSIs of both scenarios are compared to pre-collected RSSIs, the RSSIs of the abnormal scenario are about 61% more different compared to the RSSIs of the normal scenario. Therefore, intruders in buildings can be detected by considering RSSI differences.

  17. Effect of Couple Therapy Based on the Choice Theory on Social Commitment of Couples

    Directory of Open Access Journals (Sweden)

    Hossein Abbasi

    2017-09-01

    Full Text Available Background and Objective: Commitment to spouse, marriage, and family is one of the most important factors ensuring the continuity of marriage and strength of family bonds that has attracted considerable attention in the contemporary family and marriage studies. In this study, we sought to determine the effect of couple therapy based on the choice theory on the social commitment of couples. Materials and Methods: This was a quasi-experimental study with pretest-posttest design and a control group that was performed among volunteer couples visiting Isfahan Counseling and Psychology Centers in Isfahan, Iran, during 2015. The subjects consisted of 32 incompatible couples who were selected through convenience sampling and were randomly assigned into experimental (16 couples and control (16 couples groups. Then, the experimental group received nine sessions of group couple therapy during three months on family life skills based on choice theory. It is worth mentioning that the dependent variable was the social commitment of couples evaluated by the dimensions of commitment inventory of Adams and Jones (1997. The collected data were analyzed by multivariate analysis of covariance in SPSS, version 20. Results: At the post-test stage, couple therapy based on choice theory significantly enhanced social commitment in the experimental group compared to the control group (P<0.001. Conclusion: According to the findings of this study, couple therapy based on the choice theory is an effective strategy in promoting commitment and loyalty to spouse, marriage, and family and can decrease and prevent family-related problems and threats such as divorce and marital infidelity.

  18. Reliability-Based Approach for the Determination of the Required Compressive Strength of Concrete in Mix Design

    OpenAIRE

    Okasha , Nader M

    2017-01-01

    International audience; Concrete is recognized as the second most consumed product in our modern life after water. The variability in concrete properties is inevitable. The concrete mix is designed for a compressive strength that is different from, typically higher than, the value specified by the structural designer. Ways to calculate the compressive strength to be used in the mix design are provided in building and structural codes. These ways are all based on criteria related purely and on...

  19. Estimation of 1RM for knee extension based on the maximal isometric muscle strength and body composition

    OpenAIRE

    Kanada, Yoshikiyo; Sakurai, Hiroaki; Sugiura, Yoshito; Arai, Tomoaki; Koyama, Soichiro; Tanabe, Shigeo

    2017-01-01

    [Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furth...

  20. Ensemble method: Community detection based on game theory

    Science.gov (United States)

    Zhang, Xia; Xia, Zhengyou; Xu, Shengwu; Wang, J. D.

    2014-08-01

    Timely and cost-effective analytics over social network has emerged as a key ingredient for success in many businesses and government endeavors. Community detection is an active research area of relevance to analyze online social network. The problem of selecting a particular community detection algorithm is crucial if the aim is to unveil the community structure of a network. The choice of a given methodology could affect the outcome of the experiments because different algorithms have different advantages and depend on tuning specific parameters. In this paper, we propose a community division model based on the notion of game theory, which can combine advantages of previous algorithms effectively to get a better community classification result. By making experiments on some standard dataset, it verifies that our community detection model based on game theory is valid and better.

  1. Route Choice Model Based on Game Theory for Commuters

    Directory of Open Access Journals (Sweden)

    Licai Yang

    2016-06-01

    Full Text Available The traffic behaviours of commuters may cause traffic congestion during peak hours. Advanced Traffic Information System can provide dynamic information to travellers. Due to the lack of timeliness and comprehensiveness, the provided information cannot satisfy the travellers’ needs. Since the assumptions of traditional route choice model based on Expected Utility Theory conflict with the actual situation, a route choice model based on Game Theory is proposed to provide reliable route choice to commuters in actual situation in this paper. The proposed model treats the alternative routes as game players and utilizes the precision of predicted information and familiarity of traffic condition to build a game. The optimal route can be generated considering Nash Equilibrium by solving the route choice game. Simulations and experimental analysis show that the proposed model can describe the commuters’ routine route choice decisionexactly and the provided route is reliable.

  2. Towards Strengths-Based Planning Strategies for Rural Localities in Finland

    Directory of Open Access Journals (Sweden)

    Rönkkö Emilia

    2017-09-01

    Full Text Available In this article, we will introduce the topic of strengths-based planning strategies for rural localities in Finland. The strengths-based approach focuses on capacity building and competence enhancement with the local people, encouraging communities to valorise, identify and mobilise existing but often unrecognised assets. Setting focus only on the deficiencies and problems easily inflicts a ‘surrender mentality‘ in places outside of the urbanisation impact, creating a narrative that both decision-makers and community members start to believe. Hence, the role and potential of smaller rural localities is easily forgotten by planners, politicians and the public at large. Addressing the scale of rural localities in spatial planning, we will first reflect upon the main findings from our earlier research project “Finnish rural localities in the 2010`s” conducted by Lahti University of Applied Sciences, the University of Oulu and Aalto University in 2013-2015. Findings from the research project affirmed the unfortunate consequences of rapid urbanisation, rational blueprint planning and overoptimistic expectations of growth in the 1960s and 70s, which have resulted in the state of permanent incompleteness in rural localities today. However, these localities possess many under-utilised strengths, and we consider it essential for the future development of rural localities to make the most of this potential, and not only tackle the downwards spiral. This requires the ability to engage local stakeholders around a common vision for the future, and strategic approach based on endogenous strengths. We will discuss these possibilities via two theoretically informed case studies. The first one, Vieremä, is situated in the region of Northern Savo, and the other one, Vääksy, is the main centre in the municipality of Asikkala, situated in the region of Päijät-Häme in Southern Finland. Our study design can be characterised as qualitative research

  3. Fire and Heat Spreading Model Based on Cellular Automata Theory

    Science.gov (United States)

    Samartsev, A. A.; Rezchikov, A. F.; Kushnikov, V. A.; Ivashchenko, V. A.; Bogomolov, A. S.; Filimonyuk, L. Yu; Dolinina, O. N.; Kushnikov, O. V.; Shulga, T. E.; Tverdokhlebov, V. A.; Fominykh, D. S.

    2018-05-01

    The distinctive feature of the proposed fire and heat spreading model in premises is the reduction of the computational complexity due to the use of the theory of cellular automata with probability rules of behavior. The possibilities and prospects of using this model in practice are noted. The proposed model has a simple mechanism of integration with agent-based evacuation models. The joint use of these models could improve floor plans and reduce the time of evacuation from premises during fires.

  4. Validating the predictions of case-based decision theory

    OpenAIRE

    Radoc, Benjamin

    2015-01-01

    Real-life decision-makers typically do not know all possible outcomes arising from alternative courses of action. Instead, when people face a problem, they may rely on the recollection of their past personal experience: the situation, the action taken, and the accompanying consequence. In addition, the applicability of a past experience in decision-making may depend on how similar the current problem is to situations encountered previously. Case-based decision theory (CBDT), proposed by Itzha...

  5. A dependent stress-strength interference model based on mixed copula function

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Jian Xiong; An, Zong Wen; Liu, Bo [School of Mechatronics Engineering, Lanzhou University of Technology, Lanzhou (China)

    2016-10-15

    In the traditional Stress-strength interference (SSI) model, stress and strength must satisfy the basic assumption of mutual independence. However, a complex dependence between stress and strength exists in practical engineering. To evaluate structural reliability under the case that stress and strength are dependent, a mixed copula function is introduced to a new dependent SSI model. This model can fully characterize the dependence between stress and strength. The residual square sum method and genetic algorithm are also used to estimate the unknown parameters of the model. Finally, the validity of the proposed model is demonstrated via a practical case. Results show that traditional SSI model ignoring the dependence between stress and strength more easily overestimates product reliability than the new dependent SSI model.

  6. Optimization of compressive strength in admixture-reinforced cement-based grouts

    Directory of Open Access Journals (Sweden)

    Sahin Zaimoglu, A.

    2007-12-01

    Full Text Available The Taguchi method was used in this study to optimize the unconfined (7-, 14- and 28-day compressive strength of cement-based grouts with bentonite, fly ash and silica fume admixtures. The experiments were designed using an L16 orthogonal array in which the three factors considered were bentonite (0%, 0.5%, 1.0% and 3%, fly ash (10%, 20%, 30% and 40% and silica fume (0%, 5%, 10% and 20% content. The experimental results, which were analyzed by ANOVA and the Taguchi method, showed that fly ash and silica fume content play a significant role in unconfined compressive strength. The optimum conditions were found to be: 0% bentonite, 10% fly ash, 20% silica fume and 28 days of curing time. The maximum unconfined compressive strength reached under the above optimum conditions was 17.1 MPa.En el presente trabajo se ha intentado optimizar, mediante el método de Taguchi, las resistencias a compresión (a las edades de 7, 14 y 28 días de lechadas de cemento reforzadas con bentonita, cenizas volantes y humo de sílice. Se diseñaron los experimentos de acuerdo con un arreglo ortogonal tipo L16 en el que se contemplaban tres factores: la bentonita (0, 0,5, 1 y 3%, las cenizas volantes (10, 20, 30 y 40% y el humo de sílice (0, 5, 10 y 20% (porcentajes en peso del sólido. Los datos obtenidos se analizaron con mediante ANOVA y el método de Taguchi. De acuerdo con los resultados experimentales, el contenido tanto de cenizas volantes como de humo de sílice desempeña un papel significativo en la resistencia a compresión. Por otra parte, las condiciones óptimas que se han identificado son: 0% bentonita, 10% cenizas volantes, 20% humo de sílice y 28 días de tiempo de curado. La resistencia a compresión máxima conseguida en las anteriores condiciones era de 17,1 MPa.

  7. Novel Received Signal Strength-Based Indoor Location System: Development and Testing

    Directory of Open Access Journals (Sweden)

    Álvarez Yuri

    2010-01-01

    Full Text Available A received signal strength- (RSS-based indoor location method (ILS for person/assets location in indoor scenarios is presented in this paper. Theoretical bases of the method are the integral equations relating the electromagnetic (EM fields with their sources, establishing a cost function relating the measured field at the receivers and the unknown position of the transmitter. The aim is to improve the EM characterization of the scenario yielding in a more accurate indoor location method. Regarding network infrastructure implementation, a set of receivers are deployed through the coverage area, measuring the RSS value from a transmitter node which is attached to the asset to be located. The location method is evaluated in several indoor scenarios using portable measurement equipment. The next step has been the network hardware implementation using a wireless sensor network: for this purpose, ZigBee nodes have been selected. Finally, RSS measurements variability due to multipath effects and nonline-of-sight between transmitter and receiver nodes is mitigated using calibration and a correction based on the difference between the free space field decay law and the measured RSS.

  8. What Communication Theories Can Teach the Designer of Computer-Based Training.

    Science.gov (United States)

    Larsen, Ronald E.

    1985-01-01

    Reviews characteristics of computer-based training (CBT) that make application of communication theories appropriate and presents principles from communication theory (e.g., general systems theory, symbolic interactionism, rule theories, and interpersonal communication theories) to illustrate how CBT developers can profitably apply them to…

  9. A discrete stress-strength interference model based on universal generating function

    International Nuclear Information System (INIS)

    An Zongwen; Huang Hongzhong; Liu Yu

    2008-01-01

    Continuous stress-strength interference (SSI) model regards stress and strength as continuous random variables with known probability density function. This, to some extent, results in a limitation of its application. In this paper, stress and strength are treated as discrete random variables, and a discrete SSI model is presented by using the universal generating function (UGF) method. Finally, case studies demonstrate the validity of the discrete model in a variety of circumstances, in which stress and strength can be represented by continuous random variables, discrete random variables, or two groups of experimental data

  10. Systems theory as a framework for examining a college campus-based support program for the former foster youth.

    Science.gov (United States)

    Schelbe, Lisa; Randolph, Karen A; Yelick, Anna; Cheatham, Leah P; Groton, Danielle B

    2018-01-01

    Increased attention to former foster youth pursuing post-secondary education has resulted in the creation of college campus based support programs to address their need. However, limited empirical evidence and theoretical knowledge exist about these programs. This study seeks to describe the application of systems theory as a framework for examining a college campus based support program for former foster youth. In-depth semi-structured interviews were conducted with 32 program stakeholders including students, mentors, collaborative members, and independent living program staff. Using qualitative data analysis software, holistic coding techniques were employed to analyze interview transcripts. Then applying principles of extended case method using systems theory, data were analyzed. Findings suggest systems theory serves as a framework for understanding the functioning of a college campus based support program. The theory's concepts help delineate program components and roles of stakeholders; outline boundaries between and interactions among stakeholders; and identify program strengths and weakness. Systems theory plays an important role in identifying intervention components and providing a structure through which to identify and understand program elements as a part of the planning process. This study highlights the utility of systems theory as a framework for program planning and evaluation.

  11. Theoretical Conversions of Different Hardness and Tensile Strength for Ductile Materials Based on Stress-Strain Curves

    Science.gov (United States)

    Chen, Hui; Cai, Li-Xun

    2018-04-01

    Based on the power-law stress-strain relation and equivalent energy principle, theoretical equations for converting between Brinell hardness (HB), Rockwell hardness (HR), and Vickers hardness (HV) were established. Combining the pre-existing relation between the tensile strength ( σ b ) and Hollomon parameters ( K, N), theoretical conversions between hardness (HB/HR/HV) and tensile strength ( σ b ) were obtained as well. In addition, to confirm the pre-existing σ b -( K, N) relation, a large number of uniaxial tensile tests were conducted in various ductile materials. Finally, to verify the theoretical conversions, plenty of statistical data listed in ASTM and ISO standards were adopted to test the robustness of the converting equations with various hardness and tensile strength. The results show that both hardness conversions and hardness-strength conversions calculated from the theoretical equations accord well with the standard data.

  12. Estimation of 1RM for knee extension based on the maximal isometric muscle strength and body composition.

    Science.gov (United States)

    Kanada, Yoshikiyo; Sakurai, Hiroaki; Sugiura, Yoshito; Arai, Tomoaki; Koyama, Soichiro; Tanabe, Shigeo

    2017-11-01

    [Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furthermore, multiple regression analysis was performed, with data regarding the body composition incorporated as another independent variable, in addition to the maximal isometric muscle strength. [Results] Through single regression analysis with the maximal isometric muscle strength as an independent variable, the following regression formula was created: 1RM (kg)=0.714 + 0.783 × maximal isometric muscle strength (kgf). On multiple regression analysis, only the total muscle mass was extracted. [Conclusion] A highly accurate regression formula to estimate 1RM was created based on both the maximal isometric muscle strength and body composition. Using a hand-held dynamometer and body composition analyzer, it was possible to measure these items in a short time, and obtain clinically useful results.

  13. Principle-based concept analysis: intentionality in holistic nursing theories.

    Science.gov (United States)

    Aghebati, Nahid; Mohammadi, Eesa; Ahmadi, Fazlollah; Noaparast, Khosrow Bagheri

    2015-03-01

    This is a report of a principle-based concept analysis of intentionality in holistic nursing theories. A principle-based concept analysis method was used to analyze seven holistic theories. The data included eight books and 31 articles (1998-2011), which were retrieved through MEDLINE and CINAHL. Erickson, Kriger, Parse, Watson, and Zahourek define intentionality as a capacity, a focused consciousness, and a pattern of human being. Rogers and Newman do not explicitly mention intentionality; however, they do explain pattern and consciousness (epistemology). Intentionality has been operationalized as a core concept of nurse-client relationships (pragmatic). The theories are consistent on intentionality as a noun and as an attribute of the person-intentionality is different from intent and intention (linguistic). There is ambiguity concerning the boundaries between intentionality and consciousness (logic). Theoretically, intentionality is an evolutionary capacity to integrate human awareness and experience. Because intentionality is an individualized concept, we introduced it as "a matrix of continuous known changes" that emerges in two forms: as a capacity of human being and as a capacity of transpersonal caring. This study has produced a theoretical definition of intentionality and provides a foundation for future research to further investigate intentionality to better delineate its boundaries. © The Author(s) 2014.

  14. Theory-based practice in a major medical centre.

    Science.gov (United States)

    Alligood, Martha Raile

    2011-11-01

    This project was designed to improve care quality and nursing staff satisfaction. Nursing theory structures thought and action as demonstrated by evidence of improvement in complex health-care settings. Nursing administrators selected Modelling and Role-Modelling (MRM) for the theory-based practice goal in their strategic plan. An action research approach structured implementation of MRM in a 1-year consultation project in 2001-2002. Quality of health care improved according to national quality assessment ratings, as well as patient satisfaction and nurse satisfaction. Modelling and Role-Modelling demonstrated capacity to structure nursing thought and action in patient care in a major medical centre. Uniformity of patient care language was valued by nurses as well as by allied health providers who wished to learn the holistic MRM style of practice. The processes of MRM and action research contributed to project success. A positive health-care change project was carried out in a large medical centre with action research. Introducing MRM theory-based practice was a beneficial decision by nursing administration that improved care and nurse satisfaction. Attention to nursing practice stimulated career development among the nurses to pursue bachelors, masters, and doctoral degrees. © 2011 Blackwell Publishing Ltd.

  15. Quantum game theory based on the Schmidt decomposition

    International Nuclear Information System (INIS)

    Ichikawa, Tsubasa; Tsutsui, Izumi; Cheon, Taksu

    2008-01-01

    We present a novel formulation of quantum game theory based on the Schmidt decomposition, which has the merit that the entanglement of quantum strategies is manifestly quantified. We apply this formulation to 2-player, 2-strategy symmetric games and obtain a complete set of quantum Nash equilibria. Apart from those available with the maximal entanglement, these quantum Nash equilibria are extensions of the Nash equilibria in classical game theory. The phase structure of the equilibria is determined for all values of entanglement, and thereby the possibility of resolving the dilemmas by entanglement in the game of Chicken, the Battle of the Sexes, the Prisoners' Dilemma, and the Stag Hunt, is examined. We find that entanglement transforms these dilemmas with each other but cannot resolve them, except in the Stag Hunt game where the dilemma can be alleviated to a certain degree

  16. Process for producing silicon nitride based articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.; Buljan, S.T.; Neil, J.T.

    1991-09-10

    A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  17. Performance Based Evaluation of Concrete Strength under Various Curing Conditions to Investigate Climate Change Effects

    Directory of Open Access Journals (Sweden)

    Tae-Kyun Kim

    2015-07-01

    Full Text Available Recently, the manifestation of global warming-induced climate change has been observed through super typhoons, heavy snowfalls, torrential rains, and extended heat waves. These climate changes have been occurring all over the world and natural disasters have caused severe damage and deterioration of concrete structures and infrastructure. In an effort to deal with these problems due to extreme and abnormal climate changes, studies have been conducted to develop construction technologies and design guidelines. Nevertheless, study results applicable to construction sites continue to be ineffective and insufficient. Therefore, this study proposes ways to cope with climate change by considering the effect of concrete curing condition variations on concrete material performance. More specifically, the 3-, 7- and 28-day compressive and split tensile strength properties of concrete mix cured under various climatic factors including temperature, relative humidity, wind speed, and sunlight exposure time were evaluated to determine whether the concrete meets the current design requirements. Thereafter, a performance based evaluation (PBE was performed using satisfaction probabilities based on the test values to understand the problems associated with the current mix proportion design practice and to identify countermeasures to deal with climate change-induced curing conditions.

  18. Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on tunable functionalized copolymers

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

    2015-01-01

    system, with respect to functionalization, is achieved. It is investigated how the different functionalization variables affect essential DE properties, including dielectric permittivity, dielectric loss, elastic modulus and dielectric breakdown strength, and the optimal degree of chemical......%) was obtained without compromising other vital DE properties such as elastic modulus, gel fraction, dielectric and viscous loss and electrical breakdown strength....

  19. Comparison of the tensile bond strength of high-noble, noble, and base metal alloys bonded to enamel.

    Science.gov (United States)

    Sen, D; Nayir, E; Pamuk, S

    2000-11-01

    Although the bond strengths of various resin composite luting materials have been reported in the literature, the evaluation of these systems with various cast alloys of different compositions has not been completely clarified. To evaluate the tensile bond strength of sandblasted high-noble, noble, and base metal alloys bonded to etched enamel by 2 different bonding agents of different chemical composition: Panavia-Ex (BIS-GMA) and Super-Bond (4-META acrylic). Flat enamel surfaces were prepared on buccal surfaces of 60 extracted noncarious human incisors. Teeth were divided into 3 groups of 20 each. Twenty circular disks of 5 mm diameter were prepared for casting for each group. Group I was cast with a high-noble, group II with a noble, and group III with a base metal alloy. The surfaces of the disks were sandblasted with 250 microm Al(2)O(3). Ten disks of each group were bonded to exposed enamel surfaces with Super-Bond and 10 disks with Panavia-Ex as recommended by the manufacturer. The tensile bond strength was measured with an Instron universal testing machine with a crosshead speed of 0.5 mm/min until failure occurred. Two-way ANOVA was used to evaluate the results. The differences in bond strengths of Super-Bond and Panavia-Ex with different alloys were not significant. The highest bond strengths were obtained in base metal alloys, followed by noble and high-noble alloys. These results were significant. Panavia-Ex and Super-Bond exhibited comparable tensile bond strengths. For both luting agents, the highest bond strengths were achieved with base metal alloys and the lowest with high-noble alloys.

  20. Shear bond strength of a denture base acrylic resin and gingiva-colored indirect composite material to zirconia ceramics.

    Science.gov (United States)

    Kubochi, Kei; Komine, Futoshi; Fushiki, Ryosuke; Yagawa, Shogo; Mori, Serina; Matsumura, Hideo

    2017-04-01

    To evaluate the shear bond strengths of two gingiva-colored materials (an indirect composite material and a denture base acrylic resin) to zirconia ceramics and determine the effects of surface treatment with various priming agents. A gingiva-colored indirect composite material (CER) or denture base acrylic resin (PAL) was bonded to zirconia disks with unpriming (UP) or one of seven priming agents (n=11 each), namely, Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Act), Metal Link (MEL), Meta Fast Bonding Liner (MFB), MR. bond (MRB), and V-Primer (VPR). Shear bond strength was determined before and after 5000 thermocycles. The data were analyzed with the Kruskal-Wallis test and Steel-Dwass test. The mean pre-/post-thermalcycling bond strengths were 1.0-14.1MPa/0.1-12.1MPa for the CER specimen and 0.9-30.2MPa/0.1-11.1MPa for the PAL specimen. For the CER specimen, the ALP, CPB, and CPB+Act groups had significantly higher bond strengths among the eight groups, at both 0 and 5000 thermocycles. For the PAL specimen, shear bond strength was significantly lower after thermalcycling in all groups tested. After 5000 thermocycles, bond strengths were significantly higher in the CPB and CPB+Act groups than in the other groups. For the PAL specimens, bond strengths were significantly lower after thermalcycling in all groups tested. The MDP functional monomer improved bonding of a gingiva-colored indirect composite material and denture base acrylic resin to zirconia ceramics. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  1. [Development and application of component-based Chinese medicine theory].

    Science.gov (United States)

    Zhang, Jun-Hua; Fan, Guan-Wei; Zhang, Han; Fan, Xiao-Hui; Wang, Yi; Liu, Li-Mei; Li, Chuan; Gao, Yue; Gao, Xiu-Mei; Zhang, Bo-Li

    2017-11-01

    Traditional Chinese medicine (TCM) prescription is the main therapies for disease prevention and treatment in Chinese medicine. Following the guidance of the theory of TCM and developing drug by composing prescriptions of TCM materials and pieces, it is a traditional application mode of TCM, and still widely used in clinic. TCM prescription has theoretical advantages and rich clinical application experience in dealing with multi-factor complex diseases, but scientific research is relatively weak. The lack of scientific cognition of the effective substances and mechanism of Chinese medicine leads to insufficient understanding of the efficacy regularity, which affects the stability of effect and hinders the improvement of quality of Chinese medicinal products. Component-based Chinese medicine (CCM) is an innovation based on inheritance, which breaks through the tradition of experience-based prescription and realize the transformation of compatibility from herbal pieces to components. CCM is an important achievement during the research process of modernization of Chinese medicine. Under the support of three national "973" projects, in order to reveal the scientific connotation of the prescription compatibility theory and develop innovative Chinese drugs, we have launched theoretical innovation and technological innovation around the "two relatively clear", and opened up the research field of CCM. CCM is an innovation based on inheritance, breaking through the tradition of experience based prescription, and realizing the transformation from compatibility of herbal pieces to component compatibility, which is an important achievement of the modernization of traditional Chinese medicine. In the past more than 10 years, with the deepening of research and the expansion of application, the theory and methods of CCM and efficacy-oriented compatibility have been continuously improved. The value of CCM is not only in developing new drug, more important is to build a

  2. The strength compass

    DEFF Research Database (Denmark)

    Ledertoug, Mette Marie

    of agreement/disagreement. Also the child/teacher is asked whether the actual strength is important and if he or she has the possibilities to apply the strength in the school. In a PhDproject ‘Strengths-based Learning - Children’s Character Strengths as Means to their Learning Potential’ 750 Danish children......Individual paper presentation: The ‘Strength Compass’. The results of a PhDresearch project among schoolchildren (age 6-16) identifying VIAstrengths concerning age, gender, mother-tongue-langue and possible child psychiatric diagnosis. Strengths-based interventions in schools have a theoretical...... Psychological Publishing Company. ‘The Strength Compass’ is a computer/Ipad based qualitative tool to identify the strengths of a child by a self-survey or a teacher’s survey. It is designed as a visual analogue scale with a statement of the strength in which the child/teacher may declare the degree...

  3. Extracting dirt from water: a strengths-based approach to religion for African American same-gender-loving men.

    Science.gov (United States)

    Lassiter, Jonathan Mathias

    2014-02-01

    Religion is one of the most powerful and ubiquitous forces in African American same-gender-loving (SGL) men's lives. Research indicates that it has both positive and negative influences on the health behaviors and outcomes of this population. This paper presents a review of the literature that examines religion as a risk and protective factor for African American SGL men. A strengths-based approach to religion that aims to utilize its protective qualities and weaken its relation to risk is proposed. Finally, recommendations are presented for the use of a strengths-based approach to religion in clinical work and research.

  4. Prediction of the strength of concrete radiation shielding based on LS-SVM

    International Nuclear Information System (INIS)

    Juncai, Xu; Qingwen, Ren; Zhenzhong, Shen

    2015-01-01

    Highlights: • LS-SVM was introduced for prediction of the strength of RSC. • A model for prediction of the strength of RSC was implemented. • The grid search algorithm was used to optimize the parameters of the LS-SVM. • The performance of LS-SVM in predicting the strength of RSC was evaluated. - Abstract: Radiation-shielding concrete (RSC) and conventional concrete differ in strength because of their distinct constituents. Predicting the strength of RSC with different constituents plays a vital role in radiation shielding (RS) engineering design. In this study, a model to predict the strength of RSC is established using a least squares-support vector machine (LS-SVM) through grid search algorithm. The algorithm is used to optimize the parameters of the LS-SVM on the basis of traditional prediction methods for conventional concrete. The predicted results of the LS-SVM model are compared with the experimental data. The results of the prediction are stable and consistent with the experimental results. In addition, the studied parameters exhibit significant effects on the simulation results. Therefore, the proposed method can be applied in predicting the strength of RSC, and the predicted results can be adopted as an important reference for RS engineering design

  5. Forewarning model for water pollution risk based on Bayes theory.

    Science.gov (United States)

    Zhao, Jun; Jin, Juliang; Guo, Qizhong; Chen, Yaqian; Lu, Mengxiong; Tinoco, Luis

    2014-02-01

    In order to reduce the losses by water pollution, forewarning model for water pollution risk based on Bayes theory was studied. This model is built upon risk indexes in complex systems, proceeding from the whole structure and its components. In this study, the principal components analysis is used to screen out index systems. Hydrological model is employed to simulate index value according to the prediction principle. Bayes theory is adopted to obtain posterior distribution by prior distribution with sample information which can make samples' features preferably reflect and represent the totals to some extent. Forewarning level is judged on the maximum probability rule, and then local conditions for proposing management strategies that will have the effect of transforming heavy warnings to a lesser degree. This study takes Taihu Basin as an example. After forewarning model application and vertification for water pollution risk from 2000 to 2009 between the actual and simulated data, forewarning level in 2010 is given as a severe warning, which is well coincide with logistic curve. It is shown that the model is rigorous in theory with flexible method, reasonable in result with simple structure, and it has strong logic superiority and regional adaptability, providing a new way for warning water pollution risk.

  6. Cluster analysis of novel isometric strength measures produces a valid and evidence-based classification structure for wheelchair track racing.

    Science.gov (United States)

    Connick, Mark J; Beckman, Emma; Vanlandewijck, Yves; Malone, Laurie A; Blomqvist, Sven; Tweedy, Sean M

    2017-11-25

    The Para athletics wheelchair-racing classification system employs best practice to ensure that classes comprise athletes whose impairments cause a comparable degree of activity limitation. However, decision-making is largely subjective and scientific evidence which reduces this subjectivity is required. To evaluate whether isometric strength tests were valid for the purposes of classifying wheelchair racers and whether cluster analysis of the strength measures produced a valid classification structure. Thirty-two international level, male wheelchair racers from classes T51-54 completed six isometric strength tests evaluating elbow extensors, shoulder flexors, trunk flexors and forearm pronators and two wheelchair performance tests-Top-Speed (0-15 m) and Top-Speed (absolute). Strength tests significantly correlated with wheelchair performance were included in a cluster analysis and the validity of the resulting clusters was assessed. All six strength tests correlated with performance (r=0.54-0.88). Cluster analysis yielded four clusters with reasonable overall structure (mean silhouette coefficient=0.58) and large intercluster strength differences. Six athletes (19%) were allocated to clusters that did not align with their current class. While the mean wheelchair racing performance of the resulting clusters was unequivocally hierarchical, the mean performance of current classes was not, with no difference between current classes T53 and T54. Cluster analysis of isometric strength tests produced classes comprising athletes who experienced a similar degree of activity limitation. The strength tests reported can provide the basis for a new, more transparent, less subjective wheelchair racing classification system, pending replication of these findings in a larger, representative sample. This paper also provides guidance for development of evidence-based systems in other Para sports. © Article author(s) (or their employer(s) unless otherwise stated in the text of

  7. Workplace-based assessment: raters' performance theories and constructs.

    Science.gov (United States)

    Govaerts, M J B; Van de Wiel, M W J; Schuwirth, L W T; Van der Vleuten, C P M; Muijtjens, A M M

    2013-08-01

    Weaknesses in the nature of rater judgments are generally considered to compromise the utility of workplace-based assessment (WBA). In order to gain insight into the underpinnings of rater behaviours, we investigated how raters form impressions of and make judgments on trainee performance. Using theoretical frameworks of social cognition and person perception, we explored raters' implicit performance theories, use of task-specific performance schemas and the formation of person schemas during WBA. We used think-aloud procedures and verbal protocol analysis to investigate schema-based processing by experienced (N = 18) and inexperienced (N = 16) raters (supervisor-raters in general practice residency training). Qualitative data analysis was used to explore schema content and usage. We quantitatively assessed rater idiosyncrasy in the use of performance schemas and we investigated effects of rater expertise on the use of (task-specific) performance schemas. Raters used different schemas in judging trainee performance. We developed a normative performance theory comprising seventeen inter-related performance dimensions. Levels of rater idiosyncrasy were substantial and unrelated to rater expertise. Experienced raters made significantly more use of task-specific performance schemas compared to inexperienced raters, suggesting more differentiated performance schemas in experienced raters. Most raters started to develop person schemas the moment they began to observe trainee performance. The findings further our understanding of processes underpinning judgment and decision making in WBA. Raters make and justify judgments based on personal theories and performance constructs. Raters' information processing seems to be affected by differences in rater expertise. The results of this study can help to improve rater training, the design of assessment instruments and decision making in WBA.

  8. A Routing Protocol Based on Received Signal Strength for Underwater Wireless Sensor Networks (UWSNs

    Directory of Open Access Journals (Sweden)

    Meiju Li

    2017-11-01

    Full Text Available Underwater wireless sensor networks (UWSNs are featured by long propagation delay, limited energy, narrow bandwidth, high BER (Bit Error Rate and variable topology structure. These features make it very difficult to design a short delay and high energy-efficiency routing protocol for UWSNs. In this paper, a routing protocol independent of location information is proposed based on received signal strength (RSS, which is called RRSS. In RRSS, a sensor node firstly establishes a vector from the node to a sink node; the length of the vector indicates the RSS of the beacon signal (RSSB from the sink node. A node selects the next-hop along the vector according to RSSB and the RSS of a hello packet (RSSH. The node nearer to the vector has higher priority to be a candidate next-hop. To avoid data packets being delivered to the neighbor nodes in a void area, a void-avoiding algorithm is introduced. In addition, residual energy is considered when selecting the next-hop. Meanwhile, we establish mathematic models to analyze the robustness and energy efficiency of RRSS. Lastly, we conduct extensive simulations, and the simulation results show RRSS can save energy consumption and decrease end-to-end delay.

  9. Calculation of marine propeller static strength based on coupled BEM/FEM

    Directory of Open Access Journals (Sweden)

    YE Liyu

    2017-10-01

    Full Text Available [Objectives] The reliability of propeller stress has a great influence on the safe navigation of a ship. To predict propeller stress quickly and accurately,[Methods] a new numerical prediction model is developed by coupling the Boundary Element Method(BEMwith the Finite Element Method (FEM. The low order BEM is used to calculate the hydrodynamic load on the blades, and the Prandtl-Schlichting plate friction resistance formula is used to calculate the viscous load. Next, the calculated hydrodynamic load and viscous correction load are transmitted to the calculation of the Finite Element as surface loads. Considering the particularity of propeller geometry, a continuous contact detection algorithm is developed; an automatic method for generating the finite element mesh is developed for the propeller blade; a code based on the FEM is compiled for predicting blade stress and deformation; the DTRC 4119 propeller model is applied to validate the reliability of the method; and mesh independence is confirmed by comparing the calculated results with different sizes and types of mesh.[Results] The results show that the calculated blade stress and displacement distribution are reliable. This method avoids the process of artificial modeling and finite element mesh generation, and has the advantages of simple program implementation and high calculation efficiency.[Conclusions] The code can be embedded into the code of theoretical and optimized propeller designs, thereby helping to ensure the strength of designed propellers and improve the efficiency of propeller design.

  10. Weighted Least Squares Techniques for Improved Received Signal Strength Based Localization

    Directory of Open Access Journals (Sweden)

    José R. Casar

    2011-09-01

    Full Text Available The practical deployment of wireless positioning systems requires minimizing the calibration procedures while improving the location estimation accuracy. Received Signal Strength localization techniques using propagation channel models are the simplest alternative, but they are usually designed under the assumption that the radio propagation model is to be perfectly characterized a priori. In practice, this assumption does not hold and the localization results are affected by the inaccuracies of the theoretical, roughly calibrated or just imperfect channel models used to compute location. In this paper, we propose the use of weighted multilateration techniques to gain robustness with respect to these inaccuracies, reducing the dependency of having an optimal channel model. In particular, we propose two weighted least squares techniques based on the standard hyperbolic and circular positioning algorithms that specifically consider the accuracies of the different measurements to obtain a better estimation of the position. These techniques are compared to the standard hyperbolic and circular positioning techniques through both numerical simulations and an exhaustive set of real experiments on different types of wireless networks (a wireless sensor network, a WiFi network and a Bluetooth network. The algorithms not only produce better localization results with a very limited overhead in terms of computational cost but also achieve a greater robustness to inaccuracies in channel modeling.

  11. Hydroxyapatite-chitosan based bioactive hybrid biomaterials with improved mechanical strength

    Science.gov (United States)

    Zima, A.

    2018-03-01

    Composites consisting of hydroxyapatite (HA) and chitosan (CTS) have recently been intensively studied. In this work, a novel inorganic-organic (I/O) HA/CTS materials in the form of granules were prepared through a simple solution-based chemical method. During the synthesis of these hybrids, the electrostatic complexes between positively charged, protonated amine groups of chitosan and the negative phosphate species (HPO42 - and H2PO4-) were formed. Our biocomposites belong to the class I of hybrids, which was confirmed by FTIR studies. XRD analysis revealed that the obtained materials consisted of hydroxyapatite as the only crystalline phase. Homogeneous dispersion of the components in HA/CTS composites was confirmed. The use of 17 wt% and 23 wt% of chitosan resulted in approximately 12-fold and 16-fold increase in the compressive strength of HA/CTS as compared to the non-modified HA material. During incubation of the studied materials in SBF, pH of the solution remained close to the physiological one. Formation of apatite layer on their surfaces indicated bioactive nature of the developed biomaterials.

  12. STUDY OF HORIZONTAL SCREEN STRENGTH CREATED BY INJECTION TECHNOLOGY CEMENT BINDER BASED

    Directory of Open Access Journals (Sweden)

    BORISOV A. A.

    2016-09-01

    Full Text Available Annotation. Formulation of the problem. An important indicator in the planning of injection works is a particle size distribution of the soil and the very composition of injection. The ideal case is to comply with the injection optimum ratio between the size of particles in solution and injectable medium. This ratio corresponds to complete impregnation of the environment. Today in the field of building technologies known classical methods of grouting with the injection process [9]. This may be a cementation or silicification with different chemical compositions. Due to the fact that we have proposed an innovative technology of impervious curtain device, special attention should be paid to the performance and physical and mechanical properties of the resulting soil-injection. This is due to the fact that the proposed technology provides for lesser known technical solutions, the use of which should ultimately result in impervious screens with desired properties. Goal. The aim of this study is to investigate the properties of the resulting soil-concrete impervious screen. Such structures should have defined a number of physical and mechanical properties. In this paper, it was of interest to study the compressive strength of the resulting soil-concrete structure. Conclusion. As a result of experimentation and implementation of complex obtained experimentally-statistical models that describe the main soil-quality indicators. Based on these data is possible optimal selection of formulation and technological structure for sandy soils with different modules size of its particles.

  13. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix and Polymer Matrix Composite Structures

    Science.gov (United States)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan J.; Walton, Owen J.; Arnold, Steven M.

    2016-01-01

    Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. This effort involves coupling three independently developed software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/ Life), and (3) the Abaqus finite element analysis (FEA) program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating unit cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC. Abaqus is used at the global scale to model the overall composite structure. An Abaqus user-defined material (UMAT) interface, referred to here as "FEAMAC/CARES," was developed that enables MAC/GMC and CARES/Life to operate seamlessly with the Abaqus FEA code. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events, which incrementally progress and lead to ultimate structural failure. This report describes the FEAMAC/CARES methodology and discusses examples that illustrate the performance of the tool. A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.

  14. Distributed, signal strength-based indoor localization algorithm for use in healthcare environments.

    Science.gov (United States)

    Wyffels, Jeroen; De Brabanter, Jos; Crombez, Pieter; Verhoeve, Piet; Nauwelaers, Bart; De Strycker, Lieven

    2014-11-01

    In current healthcare environments, a trend toward mobile and personalized interactions between people and nurse call systems is strongly noticeable. Therefore, it should be possible to locate patients at all times and in all places throughout the care facility. This paper aims at describing a method by which a mobile node can locate itself indoors, based on signal strength measurements and a minimal amount of yes/no decisions. The algorithm has been developed specifically for use in a healthcare environment. With extensive testing and statistical support, we prove that our algorithm can be used in a healthcare setting with an envisioned level of localization accuracy up to room revel (or region level in a corridor), while avoiding heavy investments since the hardware of an existing nurse call network can be reused. The approach opted for leads to very high scalability, since thousands of mobile nodes can locate themselves. Network timing issues and localization update delays are avoided, which ensures that a patient can receive the needed care in a time and resources efficient way.

  15. Relationships between field-based measures of strength and power and golf club head speed.

    Science.gov (United States)

    Read, Paul J; Lloyd, Rhodri S; De Ste Croix, Mark; Oliver, Jon L

    2013-10-01

    Increased golf club head speed (CHS) has been shown to result in greater driving distances and is also correlated with golf handicap. The purpose of this study was to investigate the relationships between field-based measures of strength and power and golf CHS with a secondary aim to determine the reliability of the selected tests. A correlation design was used to assess the following variables: anthropometrics, squat jump (SJ) height and squat jump peak power (SJPP), unilateral countermovement jump (CMJ) heights (right leg countermovement jump and left leg countermovement jump [LLCMJ]), bilateral CMJ heights, countermovement jump peak power (CMJPP), and medicine ball seated throw (MBST) and medicine ball rotational throw (MBRT). Fouty-eight male subjects participated in the study (age: 20.1 ± 3.2 years, height: 1.76 ± 0.07 m, mass: 72.8 ± 7.8 kg, handicap: 5.8 ± 2.2). Moderate significant correlations were reported between CHS and MBRT (r = 0.67; p golf athletes using the proposed battery of field tests. Additionally, movements that are more concentrically dominant in nature may display stronger relationships with CHS due to MBST and SJ displaying the highest explained variance after a stepwise linear regression.

  16. R2NA: Received Signal Strength (RSS Ratio-Based Node Authentication for Body Area Network

    Directory of Open Access Journals (Sweden)

    Yang Wu

    2013-12-01

    Full Text Available The body area network (BAN is an emerging branch of wireless sensor networks for personalized applications. The services in BAN usually have a high requirement on security, especially for the medical diagnosis. One of the fundamental directions to ensure security in BAN is how to provide node authentication. Traditional research using cryptography relies on prior secrets shared among nodes, which leads to high resource cost. In addition, most existing non-cryptographic solutions exploit out-of-band (OOB channels, but they need the help of additional hardware support or significant modifications to the system software. To avoid the above problems, this paper presents a proximity-based node authentication scheme, which only uses wireless modules equipped on sensors. With only one sensor and one control unit (CU in BAN, we could detect a unique physical layer characteristic, namely, the difference between the received signal strength (RSS measured on different devices in BAN. Through the above-mentioned particular difference, we can tell whether the sender is close enough to be legitimate. We validate our scheme through both theoretical analysis and experiments, which are conducted on the real Shimmer nodes. The results demonstrate that our proposed scheme has a good security performance.

  17. A communication-theory based view on telemedical communication.

    Science.gov (United States)

    Schall, Thomas; Roeckelein, Wolfgang; Mohr, Markus; Kampshoff, Joerg; Lange, Tim; Nerlich, Michael

    2003-01-01

    Communication theory based analysis sheds new light on the use of health telematics. This analysis of structures in electronic medical communication shows communicative structures with special features. Current and evolving telemedical applications are analyzed. The methodology of communicational theory (focusing on linguistic pragmatics) is used to compare it with its conventional counterpart. The semiotic model, the roles of partners, the respective message and their relation are discussed. Channels, sender, addressee, and other structural roles are analyzed for different types of electronic medical communication. The communicative processes are shown as mutual, rational action towards a common goal. The types of communication/texts are analyzed in general. Furthermore the basic communicative structures of medical education via internet are presented with their special features. The analysis shows that electronic medical communication has special features compared to everyday communication: A third participant role often is involved: the patient. Messages often are addressed to an unspecified partner or to an unspecified partner within a group. Addressing in this case is (at least partially) role-based. Communication and message often directly (rather than indirectly) influence actions of the participants. Communication often is heavily regulated including legal implications like liability, and more. The conclusion from the analysis is that the development of telemedical applications so far did not sufficiently take communicative structures into consideration. Based on these results recommendations for future developments of telemedical applications/services are given.

  18. Study on thermal wave based on the thermal mass theory

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The conservation equations for heat conduction are established based on the concept of thermal mass.We obtain a general heat conduction law which takes into account the spatial and temporal inertia of thermal mass.The general law introduces a damped thermal wave equation.It reduces to the well-known CV model when the spatial inertia of heat flux and temperature and the temporal inertia of temperature are neglected,which indicates that the CV model only considers the temporal inertia of heat flux.Numerical simulations on the propagation and superposition of thermal waves show that for small thermal perturbation the CV model agrees with the thermal wave equation based on the thermal mass theory.For larger thermal perturbation,however,the physically impossible phenomenon pre-dicted by CV model,i.e.the negative temperature induced by the thermal wave superposition,is eliminated by the general heat conduction law,which demonstrates that the present heat conduction law based on the thermal mass theory is more reasonable.

  19. Study on thermal wave based on the thermal mass theory

    Institute of Scientific and Technical Information of China (English)

    HU RuiFeng; CAO BingYang

    2009-01-01

    The conservation equations for heat conduction are established based on the concept of thermal mass. We obtain a general heat conduction law which takes into account the spatial and temporal inertia of thermal mass. The general law introduces a damped thermal wave equation. It reduces to the well-known CV model when the spatial inertia of heat flux and temperature and the temporal inertia of temperature are neglected, which indicates that the CV model only considers the temporal inertia of heat flux. Numerical simulations on the propagation and superposition of thermal waves show that for small thermal perturbation the CV model agrees with the thermal wave equation based on the thermal mass theory. For larger thermal perturbation, however, the physically impossible phenomenon pre-dicted by CV model, i.e. the negative temperature induced by the thermal wave superposition, is eliminated by the general heat conduction law, which demonstrates that the present heat conduction law based on the thermal mass theory is more reasonable.

  20. Game Theory and Risk-Based Levee System Design

    Science.gov (United States)

    Hui, R.; Lund, J. R.; Madani, K.

    2014-12-01

    Risk-based analysis has been developed for optimal levee design for economic efficiency. Along many rivers, two levees on opposite riverbanks act as a simple levee system. Being rational and self-interested, land owners on each river bank would tend to independently optimize their levees with risk-based analysis, resulting in a Pareto-inefficient levee system design from the social planner's perspective. Game theory is applied in this study to analyze decision making process in a simple levee system in which the land owners on each river bank develop their design strategies using risk-based economic optimization. For each land owner, the annual expected total cost includes expected annual damage cost and annualized construction cost. The non-cooperative Nash equilibrium is identified and compared to the social planner's optimal distribution of flood risk and damage cost throughout the system which results in the minimum total flood cost for the system. The social planner's optimal solution is not feasible without appropriate level of compensation for the transferred flood risk to guarantee and improve conditions for all parties. Therefore, cooperative game theory is then employed to develop an economically optimal design that can be implemented in practice. By examining the game in the reversible and irreversible decision making modes, the cost of decision making myopia is calculated to underline the significance of considering the externalities and evolution path of dynamic water resource problems for optimal decision making.

  1. Application of the heuristically based GPT theory to termohydraulic problems

    International Nuclear Information System (INIS)

    Alvim, A.C.M.

    1988-01-01

    Application of heuristically based generalized perturbation theory (GPT) to the thermohydraulic (generally nonlinear) field is here illustrated. After a short description of the general methodology, the (linear) equations governing the importance function relevant to a generic multichannel problem are derived, within the physical model adopted in the COBRA IV-I Code. These equations are put in a form which should benefit of the calculational scheme of the original COBRA Code in the sense that only minor changes of it (mostly implying physical constants and source terms redefinitions) should be necessary for their solutions. (author) [pt

  2. Transportation optimization with fuzzy trapezoidal numbers based on possibility theory.

    Science.gov (United States)

    He, Dayi; Li, Ran; Huang, Qi; Lei, Ping

    2014-01-01

    In this paper, a parametric method is introduced to solve fuzzy transportation problem. Considering that parameters of transportation problem have uncertainties, this paper develops a generalized fuzzy transportation problem with fuzzy supply, demand and cost. For simplicity, these parameters are assumed to be fuzzy trapezoidal numbers. Based on possibility theory and consistent with decision-makers' subjectiveness and practical requirements, the fuzzy transportation problem is transformed to a crisp linear transportation problem by defuzzifying fuzzy constraints and objectives with application of fractile and modality approach. Finally, a numerical example is provided to exemplify the application of fuzzy transportation programming and to verify the validity of the proposed methods.

  3. Analytical modal diffusion theory based on flux separability

    International Nuclear Information System (INIS)

    Segev, M.

    1987-01-01

    The theory provides for an iterative solution of the mathematical problem of generating the assembly-wise power distribution in a LWR through the solution of the 2-group, multidimensional, diffusion equation. The companion problems of assembly pre-homogenization and of pin power reconstruction are of no direct concern presently. The theoretical development stems from the assumption of flux separability in X, Y and Z. The assumption derives from the notion that separability holds in a great part of the interior of a LWR assembly. More important, well accurate power maps are generated with a code based on the theoretical develpment yielded by the basic assumption

  4. Developing a Theory-Based Simulation Educator Resource.

    Science.gov (United States)

    Thomas, Christine M; Sievers, Lisa D; Kellgren, Molly; Manning, Sara J; Rojas, Deborah E; Gamblian, Vivian C

    2015-01-01

    The NLN Leadership Development Program for Simulation Educators 2014 faculty development group identified a lack of a common language/terminology to outline the progression of expertise of simulation educators. The group analyzed Benner's novice-to-expert model and applied its levels of experience to simulation educator growth. It established common operational categories of faculty development and used them to organize resources that support progression toward expertise. The resulting theory-based Simulator Educator Toolkit outlines levels of ability and provides quality resources to meet the diverse needs of simulation educators and team members.

  5. Design of structurally colored surfaces based on scalar diffraction theory

    DEFF Research Database (Denmark)

    Johansen, Villads Egede; Andkjær, Jacob Anders; Sigmund, Ole

    2014-01-01

    In this paper we investigate the possibility of controlling the color and appearance of surfaces simply by modifying the height profile of the surface on a nanoscale level. The applications for such methods are numerous: new design possibilities for high-end products, color engraving on any highly...... reflective surface, paint-free text and coloration, UV-resistant coloring, etc. In this initial study, the main focus is on finding a systematic way to obtain these results. For now the simulation and optimization is based on a simple scalar diffraction theory model. From the results, several design issues...

  6. Effects of implicit theories of ability and stereotype-inconsistent information on handgrip strength in older adults: A regulatory fit perspective.

    Science.gov (United States)

    Emile, Mélanie; Chalabaev, Aina; Colson, Serge S; Vaulerin, Jerome; Falzon, Charlene; D'Arripe-Longueville, Fabienne

    2017-03-01

    This study examined whether stereotype-inconsistent information interacts with implicit theories of ability to affect handgrip strength in older adults. Eighty-two retired older adults (13 men and 69 women) from 61 to 89 years old (M age = 75.8 years; SD = 6.9) performed maximum voluntary contractions (MVC) during a handgrip task in a design manipulating implicit theories of ability and stereotype-inconsistent information related to physical decline with aging. Participants were randomly assigned to one of three groups: incremental condition, entity condition, or control group. The results showed that in the incremental condition the stereotype-inconsistent information improved the peak MVC, the average MVC, the peak rate of force development (RFD), and RFD in the initial 50 ms of the MVC. This study therefore demonstrated that individuals with an incremental mindset who are exposed to stereotype-inconsistent information can boost their physical performance. These findings are discussed from the perspective of regulatory fit (i.e., when task framing is congruent with the individual's goal). © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

  7. Compressive Strength of EN AC-44200 Based Composite Materials Strengthened with α-Al2O3 Particles

    Directory of Open Access Journals (Sweden)

    Kurzawa A.

    2017-06-01

    Full Text Available The paper presents results of compressive strength investigations of EN AC-44200 based aluminum alloy composite materials reinforced with aluminum oxide particles at ambient and at temperatures of 100, 200 and 250°C. They were manufactured by squeeze casting of the porous preforms made of α-Al2O3 particles with liquid aluminum alloy EN AC-44200. The composite materials were reinforced with preforms characterized by the porosities of 90, 80, 70 and 60 vol. %, thus the alumina content in the composite materials was 10, 20, 30 and 40 vol.%. The results of the compressive strength of manufactured materials were presented and basing on the microscopic observations the effect of the volume content of strengthening alumina particles on the cracking mechanisms during compression at indicated temperatures were shown and discussed. The highest compressive strength of 470 MPa at ambient temperature showed composite materials strengthened with 40 vol.% of α-Al2O3 particles.

  8. The influence of size and structure of metal orthodontic bracket base on bond strength on tooth enamel

    Directory of Open Access Journals (Sweden)

    Mitić Vladimir

    2009-01-01

    Full Text Available Introduction. The factors which may influence the bond strength of the applied orthodontic brackets on the tooth surface are the size and structure of the bracket base. Objective. The aim of the paper was to investigate the influence of size and shape of different types of brackets on bond strength on the enamel and analyze the remaining quality of adhesive material on the tooth surface after debonding of orthodontic brackets (adhesive remnant index - ARI. Methods. In this study, three types of metal brackets of different sizes and shapes of Dentaurum manufacturer were used (Utratrimm, Equilibrium 2, Discovery, Dentaurum, Inspringen, Germany. The brackets were applied onto the middle part of the anatomic crowns of buccal surfaces of 30 premolars extracted for orthodontic reasons. In addition, the pre-treatment of teeth by 37% orthophosphoric acid and adhesive material System1+ (Dentaurum, Germany were used. Results. The mean value of the bonded brackets bond strength of Discovery type after debonding was 8.67±0.32 MPa, while the value of the bonded brackets bond strength of Equilibrium 2 type amounted to 8.62±0.22 MPa. The value of the bonded brackets bond strength of Ultratrimm type after debonding was 8.22±0.49 MPa. There were no statistical differences in the values of bond strength regarding all three groups of the investigated orthodontic brackets (F=4.56; p<0.05. Conclusion. The base size and design of metal orthodontic brackets did not play a significant role in bond strength, while the values of ARI index were identical in all three investigated groups.

  9. The Effect of Food-Simulating Agents on the Bond Strength of Hard Chairside Reline Materials to Denture Base Resin.

    Science.gov (United States)

    Fatemi, Farzaneh Sadat; Vojdani, Mahroo; Khaledi, Amir Ali Reza

    2018-06-08

    To investigate the influence of food-simulating agents on the shear bond strength between direct hard liners and denture base acrylic resin. In addition, mode of failure was evaluated. One hundred fifty cylindrical columns of denture base resin were fabricated and bonded to three types of hard reline materials (Hard GC Reline, Tokuyama Rebase II Fast, TDV Cold Liner Rebase). Specimens of each reline material were divided into five groups (n = 10) to undergo 12-day immersion in distilled water, 0.02 N citric acid aqueous solution, heptane, and 40% ethanol/water solution at 37°C. The control group was not immersed in any solution. The shear bond strength test was performed, and the failure mode was determined. Statistics were analyzed with two-way ANOVA and chi-square test (α = 0.05). Significant interaction was found between the hard liners and food simulating agents (p < 0.001). The shear bond strength of Tokuyama in 40% ethanol and TDV in heptane decreased significantly (p = 0.001, p < 0.001 respectively); however, none of the solutions could significantly affect the shear bond strength of Hard GC Reline (p = 0.208). The mixed failure mode occurred more frequently in Hard GC Reline compared with the other liners (p < 0.001) and was predominant in specimens with higher bond strength values (p = 0.012). Food simulating agents did not adversely affect the shear bond strength of Hard GC Reline; however, ethanol and heptane decreased the bond strength of Tokuyama and TDV, respectively. These findings may provide support to dentists to recommend restricted consumption of some foods and beverages for patients who have to use dentures relined with certain hard liners. © 2018 by the American College of Prosthodontists.

  10. Flexural Strength of Acrylic Resin Denture Bases Processed by Two Different Methods

    Directory of Open Access Journals (Sweden)

    Jafar Gharechahi

    2014-09-01

    Full Text Available Background and aims. The aim of this study was to compare flexural strength of specimens processed by conventional and injection-molding techniques. Materials and methods. Conventional pressure-packed PMMA was used for conventional pressure-packed and injection-molded PMMA was used for injection-molding techniques. After processing, 15 specimens were stored in distilled water at room temperature until measured. Three-point flexural strength test was carried out. Statistical analysis was carried out by SPSS using t-test. Statistical significance was defined at P<0.05. Results. Flexural strength of injection-polymerized acrylic resin specimens was higher than that of theconventional method (P=0.006. This difference was statistically significant (P=0.006. Conclusion. Within the limitations of this study, flexural strength of acrylic resin specimens was influenced by the mold-ing technique.

  11. Retentive Shear Strengths of Various Bonding Attachment Bases: An in vitro Study

    Directory of Open Access Journals (Sweden)

    Abhishek Goyal

    2013-01-01

    Conclusion: Gemini brackets provided the best bond strengths clinically, followed by Mini Diagonali, Nu-Edge, Mini Twin, Mini Diamond and the Sapphire brackets in decreasing order as measured using the Weibull analysis.

  12. Silorane- and high filled-based"low-shrinkage" resin composites: shrinkage, flexural strength and modulus

    Directory of Open Access Journals (Sweden)

    Cesar Augusto Galvão Arrais

    2013-04-01

    Full Text Available This study compared the volumetric shrinkage (VS, flexural strength (FS and flexural modulus (FM properties of the low-shrinkage resin composite Aelite LS (Bisco to those of Filtek LS (3M ESPE and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent and the microhybrid Aelite Universal (Bisco. The composites (n = 5 were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter were obtained (n = 12 and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%. Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.

  13. Evaluation of Impact Strength of Epoxy Based Hybrid Composites Reinforced with E-Glass/Kevlar 49

    OpenAIRE

    Jogi , Subhan Ali; Moazam Baloch , Muhammad; Chandio , Ali ,; Memon , Iftikhar Ahmed; Chandio , Ghulaqm Sarwar

    2017-01-01

    International audience; In hybridization different fibers are stacked layer by layer to produce laminates have specific strength and stiffness and employed in light weight high strength applications. Physically mean fabricated hybrid composites used in aerospace, under water, body armors and armed forces establishment. In present work drop-weight impact response of hybrid composites were investigated by making laminates of hybrid composites. In Hybridization layers of E-glass (roving) and Kev...

  14. THE BIODEGRADABILITY AND MECHANICAL STRENGTH OF NUTRITIVE POTS FOR VEGETABLE PLANTING BASED ON LIGNOCELLULOSE COMPOSITE MATERIALS

    OpenAIRE

    Petronela Nechita; Elena Dobrin; Florin Ciolacu; Elena Bobu

    2010-01-01

    Considering the mild degradation strength and the fact that it may be an organic matter reserve for the soil, in the past years lignocellulosic materials have been used as fibrous raw materials in the manufacture of biodegradable nutritive pots for the seedling in vegetable containerized production. This paper analyses the behavior of the nutritive pots made from biodegradable composites for the vegetable seedling production process, focusing on their mechanical strength properties and biodeg...

  15. Category Theory as a Formal Mathematical Foundation for Model-Based Systems Engineering

    KAUST Repository

    Mabrok, Mohamed; Ryan, Michael J.

    2017-01-01

    In this paper, we introduce Category Theory as a formal foundation for model-based systems engineering. A generalised view of the system based on category theory is presented, where any system can be considered as a category. The objects

  16. Posture management program based on theory of planned behavior for adolescents with mild idiopathic scoliosis.

    Science.gov (United States)

    Choi, Jihea; Kim, Hee Soon; Kim, Gwang Suk; Lee, Hyejung; Jeon, Hye-Seon; Chung, Kyong-Mee

    2013-09-01

    The purpose of this study was to evaluate the effects of a devised posture management program based on the Theory of Planned Behavior in adolescents with mild idiopathic scoliosis. A quasi-experimental study was conducted. It involved a nonequivalent comparison group design with pretest and posttest. Forty-four female adolescents with mild idiopathic scoliosis participated; data from 35 participants (20 for the test group, 15 for the control group) were used for the final analyses. The devised posture management program ran for 6 weeks. Posture management behavioral determinants (attitude, subjective norms, perceived behavioral control, and behavioral intention) as cognitive outcomes and muscular strength and flexibility as physical outcomes were measured three times: at baseline, week 6 and week 8. Cobb's angle as another physical outcome was measured twice: at baseline and week 8. Descriptive analysis, repeated measures analysis of variance and t test were used for data analyses. Attitude, perceived control, and behavioral intention were consistently enhanced by the posture management program. The intervention increased flexibility and muscular strength and decreased Cobb's angle, which reduced spinal curvature. Frequency of posture management exercise showed a gradual increase in the test group. The results indicate that the posture management program is effective in maintaining posture management behavior in adolescents with mild idiopathic scoliosis for both cognitive and physical outcomes. The posture management program should be helpful in expanding the role of school nurses in improving the health status of adolescents with mild idiopathic scoliosis. Copyright © 2013. Published by Elsevier B.V.

  17. Transitional clerkship: an experiential course based on workplace learning theory.

    Science.gov (United States)

    Chittenden, Eva H; Henry, Duncan; Saxena, Varun; Loeser, Helen; O'Sullivan, Patricia S

    2009-07-01

    Starting clerkships is anxiety provoking for medical students. To ease the transition from preclerkship to clerkship curricula, schools offer classroom-based courses which may not be the best model for preparing learners. Drawing from workplace learning theory, the authors developed a seven-day transitional clerkship (TC) in 2007 at the University of California, San Francisco School of Medicine in which students spent half of the course in the hospital, learning routines and logistics of the wards along with their roles and responsibilities as members of ward teams. Twice, they admitted and followed a patient into the next day as part of a shadow team that had no patient-care responsibilities. Dedicated preceptors gave feedback on oral presentations and patient write-ups. Satisfaction with the TC was higher than with the previous year's classroom-based course. TC students felt clearer about their roles and more confident in their abilities as third-year students compared with previous students. TC students continued to rate the transitional course highly after their first clinical rotation. Preceptors were enthusiastic about the course and expressed willingness to commit to future TC preceptorships. The transitional course models an approach to translating workplace learning theory into practice and demonstrates improved satisfaction, better understanding of roles, and increased confidence among new third-year students.

  18. Attitude Strength.

    Science.gov (United States)

    Howe, Lauren C; Krosnick, Jon A

    2017-01-03

    Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

  19. Strength measurement of optical fibers by bending

    Science.gov (United States)

    Srubshchik, Leonid S.

    1999-01-01

    A two-point bending technique has been used not only to measure the breaking stress of optical fiber but also to predict its static and dynamic fatigue. The present theory of this test is based on elastica theory of rod. However, within the limits of elastica theory the tensile and shear stresses cannot be determined. In this paper we study dynamic and static problems for optical fiber in the two- point bending test on the base of geometrically exact theory in which rod can suffer flexure, extension, and shear. We obtain the governing partial differential equations taking into account the fact that the lateral motion of the fiber is restrained by the presence of flat parallel plates. We develop the computational methods for solving the initial and equilibrium free-boundary nonlinear planar problems. We derive the formulas for predicting of the tensile strength from strength in the bending and calculate one example.

  20. Boundary based on exchange symmetry theory for multilevel simulations. I. Basic theory.

    Science.gov (United States)

    Shiga, Motoyuki; Masia, Marco

    2013-07-28

    In this paper, we lay the foundations for a new method that allows multilevel simulations of a diffusive system, i.e., a system where a flux of particles through the boundaries might disrupt the primary region. The method is based on the use of flexible restraints that maintain the separation between inner and outer particles. It is shown that, by introducing a bias potential that accounts for the exchange symmetry of the system, the correct statistical distribution is preserved. Using a toy model consisting of non-interacting particles in an asymmetric potential well, we prove that the method is formally exact, and that it could be simplified by considering only up to a couple of particle exchanges without a loss of accuracy. A real-world test is then made by considering a hybrid MM(∗)/MM calculation of cesium ion in water. In this case, the single exchange approximation is sound enough that the results superimpose to the exact solutions. Potential applications of this method to many different hybrid QM/MM systems are discussed, as well as its limitations and strengths in comparison to existing approaches.

  1. Mechanism of Strain Rate Effect Based on Dislocation Theory

    International Nuclear Information System (INIS)

    Kun, Qin; Shi-Sheng, Hu; Li-Ming, Yang

    2009-01-01

    Based on dislocation theory, we investigate the mechanism of strain rate effect. Strain rate effect and dislocation motion are bridged by Orowan's relationship, and the stress dependence of dislocation velocity is considered as the dynamics relationship of dislocation motion. The mechanism of strain rate effect is then investigated qualitatively by using these two relationships although the kinematics relationship of dislocation motion is absent due to complicated styles of dislocation motion. The process of strain rate effect is interpreted and some details of strain rate effect are adequately discussed. The present analyses agree with the existing experimental results. Based on the analyses, we propose that strain rate criteria rather than stress criteria should be satisfied when a metal is fully yielded at a given strain rate. (condensed matter: structure, mechanical and thermal properties)

  2. Inventory control based on advanced probability theory, an application

    CERN Document Server

    Krever, Maarten; Schorr, Bernd; Wunderink, S

    2005-01-01

    Whenever stock is placed as a buffer between consumption and supply the decision when to replenish the stock is based on uncertain values of future demand and supply variables. Uncertainty exists about the replenishment lead time, about the number of demands and the quantities demanded during this period. We develop a new analytical expression for the reorder point, which is based on the desired service level and three distributions: the distribution of the quantity of single demands during lead time, the distribution of the lengths of time intervals between successive demands, and the distribution of the lead time itself. The distribution of lead time demand is derived from the distributions of individual demand quantities and not from the demand per period. It is not surprising that the resulting formulae for the mean and variance are different from those currently used. The theory developed is also applicable to periodic review systems. The system has been implemented at CERN and enables a significant enha...

  3. Recent advances in multireference-based perturbation theory

    International Nuclear Information System (INIS)

    Nakano, Haruyuki; Hirao, Kimihiko

    2003-01-01

    Accurate ab initio computational chemistry has evolved dramatically. In particular, the development of multireference-based approaches has opened up a completely new area, and has had a profound impact on the potential of theoretical chemistry. Multireference-based perturbation theory (MRPT) is an extension of the closed-shell single reference Moeller-Plesset method, and has been successfully applied to many chemical and spectroscopic problems. MRPT has established itself as an efficient technique for treating nondynamical and dynamical correlations. Usually, a complete active space self-consistent field (CASSCF) wave function is chosen as a reference function of MRPT. However, CASSCF often generates too many configurations, and the size of the active space can outgrow the capacity of the present technology. Many attempts have been proposed to reduce the dimension of CASSCF and to widen the range of applications of MRPT. This review focuses on our recent development in MRPT

  4. FUSION SEGMENTATION METHOD BASED ON FUZZY THEORY FOR COLOR IMAGES

    Directory of Open Access Journals (Sweden)

    J. Zhao

    2017-09-01

    Full Text Available The image segmentation method based on two-dimensional histogram segments the image according to the thresholds of the intensity of the target pixel and the average intensity of its neighborhood. This method is essentially a hard-decision method. Due to the uncertainties when labeling the pixels around the threshold, the hard-decision method can easily get the wrong segmentation result. Therefore, a fusion segmentation method based on fuzzy theory is proposed in this paper. We use membership function to model the uncertainties on each color channel of the color image. Then, we segment the color image according to the fuzzy reasoning. The experiment results show that our proposed method can get better segmentation results both on the natural scene images and optical remote sensing images compared with the traditional thresholding method. The fusion method in this paper can provide new ideas for the information extraction of optical remote sensing images and polarization SAR images.

  5. A Cluster Randomized Controlled Trial Testing the Effectiveness of Houvast: A Strengths-Based Intervention for Homeless Young Adults

    Science.gov (United States)

    Krabbenborg, Manon A. M.; Boersma, Sandra N.; van der Veld, William M.; van Hulst, Bente; Vollebergh, Wilma A. M.; Wolf, Judith R. L. M.

    2017-01-01

    Objective: To test the effectiveness of Houvast: a strengths-based intervention for homeless young adults. Method: A cluster randomized controlled trial was conducted with 10 Dutch shelter facilities randomly allocated to an intervention and a control group. Homeless young adults were interviewed when entering the facility and when care ended.…

  6. Care farms in the Netherlands: Attractive empowerment-oriented and strengths-based practices in the community

    NARCIS (Netherlands)

    Hassink, J.; Elings, M.; Zweekhorst, M.; Nieuwenhuizen, van den N.; Smit, A.

    2010-01-01

    Empowerment-oriented and strengths-based practices focusing on community integration have gained recognition for various client groups in recent decades. This paper discusses whether care farms in the Netherlands are relevant examples of such practices. We identify characteristics associated with

  7. Care farms in the Netherlands: attractive empowerments-oreitned and strengths-based practices in the community

    NARCIS (Netherlands)

    Hassink, J.; Zweekhorst, M.B.M.; van den Nieuwehuizen, N.; Smit, A.

    2010-01-01

    Empowerment-oriented and strengths-based practices focusing on community integration have gained recognition for various client groups in recent decades. This paper discusses whether care farms in the Netherlands are relevant examples of such practices. We identify characteristics associated with

  8. Prediction of Strength for Inhomogeneous : Defective Glass Elements Based on the Sequential Partitioning of the Data and Weibull Statistical Distribution

    NARCIS (Netherlands)

    Shabetia, Alexander; Rodichev, Yurii; Veer, F.A.; Soroka, Elena; Louter, Christian; Bos, Freek; Belis, Jan; Veer, Fred; Nijsse, Rob

    An analytical approach based on the on the sequential partitioning of the data and Weibull Statistical Distribution for inhomogeneous - defective materials is proposed. It allows assessing the guaranteed strength of glass structures for the low probability of fracture with a higher degree of

  9. A cluster randomized controlled trial testing the effectiveness of Houvast: A strengths-based intervention for homeless young adults

    NARCIS (Netherlands)

    Krabbenborg, M.A.M.; Boersma, S.N.; Veld, W.M. van der; Hulst, B. van; Vollebergh, W.A.M.; Wolf, J.R.L.M.

    2017-01-01

    Objective: To test the effectiveness of Houvast: a strengths-based intervention for homeless young adults. Method: A cluster randomized controlled trial was conducted with 10 Dutch shelter facilities randomly allocated to an intervention and a control group. Homeless young adults were interviewed

  10. Validity of the Draw-a-Person: Screening Procedure for Emotional Disturbance (DAP:SPED) in Strengths-Based Assessment

    Science.gov (United States)

    Matto, Holly C.; Naglieri, Jack A.; Clausen, Cinny

    2005-01-01

    Objective: This is the first validity study to date to examine the relationship between the Draw-A-Person: Screening Procedure for Emotional Disturbance (DAP:SPED) and strengths-based emotional and behavioral measures. The incremental predictive validity of the DAP:SPED relative to the Behavioral and Emotional Rating Scale was examined. Method:…

  11. The future of high-strength copper base conductor materials; Hochfeste Leitermaterialien auf Kupfer-Basis: quo vadis?

    Energy Technology Data Exchange (ETDEWEB)

    Freudenberger, J.; Botcharova, E.; Gaganov, A.; Lyubimova, J.; Schultz, L. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe; Witte, H.; Jones, H. [Oxford Univ. (United Kingdom). Dept. of Physics; Hermannsdoerfer, T.; Zherlitsyn, S.; Wosnitza, J. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Hochfeld-Magnetlabor; Givord, D. [Institut Neel, Grenoble (France); Barthem, V.M.T.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Boettcher, R.D.; Hannemann, K. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Goettingen (Germany). Inst. fuer Aerodynamik und Stroemungstechnik

    2008-07-01

    Conductor materials with specific mechanical properties are required in many fields of science and industry. They are optimised selectively to achieve certain properties and optimum functionality, which often makes them a key component of the system in which they are used. This contribution describes current and future applications of the copper base high-strength conductor materials developed at IFW Dresden. (orig.)

  12. Through a Different Lens: Reflecting on a Strengths-Based, Talent-Focused Approach for Twice-Exceptional Learners

    Science.gov (United States)

    Baum, Susan M.; Schader, Robin M.; Hébert, Thomas P.

    2014-01-01

    This study sought to understand the experiences of a cohort of students who entered a strengths-based private school for twice-exceptional students during middle school and successfully completed graduation requirements. Using a case study design, the researchers analyzed data collected from student and teacher interviews, parent focus groups,…

  13. Plato: A localised orbital based density functional theory code

    Science.gov (United States)

    Kenny, S. D.; Horsfield, A. P.

    2009-12-01

    The Plato package allows both orthogonal and non-orthogonal tight-binding as well as density functional theory (DFT) calculations to be performed within a single framework. The package also provides extensive tools for analysing the results of simulations as well as a number of tools for creating input files. The code is based upon the ideas first discussed in Sankey and Niklewski (1989) [1] with extensions to allow high-quality DFT calculations to be performed. DFT calculations can utilise either the local density approximation or the generalised gradient approximation. Basis sets from minimal basis through to ones containing multiple radial functions per angular momenta and polarisation functions can be used. Illustrations of how the package has been employed are given along with instructions for its utilisation. Program summaryProgram title: Plato Catalogue identifier: AEFC_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFC_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 219 974 No. of bytes in distributed program, including test data, etc.: 1 821 493 Distribution format: tar.gz Programming language: C/MPI and PERL Computer: Apple Macintosh, PC, Unix machines Operating system: Unix, Linux and Mac OS X Has the code been vectorised or parallelised?: Yes, up to 256 processors tested RAM: Up to 2 Gbytes per processor Classification: 7.3 External routines: LAPACK, BLAS and optionally ScaLAPACK, BLACS, PBLAS, FFTW Nature of problem: Density functional theory study of electronic structure and total energies of molecules, crystals and surfaces. Solution method: Localised orbital based density functional theory. Restrictions: Tight-binding and density functional theory only, no exact exchange. Unusual features: Both atom centred and uniform meshes available

  14. Investigating the Learning-Theory Foundations of Game-Based Learning: A Meta-Analysis

    Science.gov (United States)

    Wu, W-H.; Hsiao, H-C.; Wu, P-L.; Lin, C-H.; Huang, S-H.

    2012-01-01

    Past studies on the issue of learning-theory foundations in game-based learning stressed the importance of establishing learning-theory foundation and provided an exploratory examination of established learning theories. However, we found research seldom addressed the development of the use or failure to use learning-theory foundations and…

  15. Field strength and dose dependence of contrast enhancement by gadolinium-based MR contrast agents

    International Nuclear Information System (INIS)

    Rinck, P.A.; Muller, R.N.

    1999-01-01

    The relaxivities r 1 and r 2 of magnetic resonance contrast agents and the T 1 relaxation time values of tissues are strongly field dependent. We present quantitative data and simulations of different gadolinium-based extracellular fluid contrast agents and the modulation of their contrast enhancement by the magnetic field to be able to answer the following questions: How are the dose and field dependences of their contrast enhancement? Is there an interrelationship between dose and field dependence? Should one increase or decrease doses at specific fields? Nuclear magnetic relaxation dispersion data were acquired for the following contrast agents: gadopentetate dimeglumine, gadoterate meglumine, gadodiamide injection, and gadoteridol injection, as well as for several normal and pathological human tissue samples. The magnetic field range stretched from 0.0002 to 4.7 T, including the entire clinical imaging range. The data acquired were then fitted with the appropriate theoretical models. The combination of the diamagnetic relaxation rates (R 1 = 1/T 1 and R 2 = 1/T 2 ) of tissues with the respective paramagnetic contributions of the contrast agents allowed the prediction of image contrast at any magnetic field. The results revealed a nearly identical field and dose-dependent increase of contrast enhancement induced by these contrast agents within a certain dose range. The target tissue concentration (TTC) was an important though nonlinear factor for enhancement. The currently recommended dose of 0.1 mmol/kg body weight seems to be a compromise close to the lower limits of diagnostically sufficient contrast enhancement for clinical imaging at all field strengths. At low field contrast enhancement might be insufficient. Adjustment of dose or concentration, or a new class of contrast agents with optimized relaxivity, would be a valuable contribution to a better diagnostic yield of contrast enhancement at all fields. (orig.)

  16. Stochastic-Strength-Based Damage Simulation of Ceramic Matrix Composite Laminates

    Science.gov (United States)

    Nemeth, Noel N.; Mital, Subodh K.; Murthy, Pappu L. N.; Bednarcyk, Brett A.; Pineda, Evan J.; Bhatt, Ramakrishna T.; Arnold, Steven M.

    2016-01-01

    The Finite Element Analysis-Micromechanics Analysis Code/Ceramics Analysis and Reliability Evaluation of Structures (FEAMAC/CARES) program was used to characterize and predict the progressive damage response of silicon-carbide-fiber-reinforced reaction-bonded silicon nitride matrix (SiC/RBSN) composite laminate tensile specimens. Studied were unidirectional laminates [0] (sub 8), [10] (sub 8), [45] (sub 8), and [90] (sub 8); cross-ply laminates [0 (sub 2) divided by 90 (sub 2),]s; angled-ply laminates [plus 45 (sub 2) divided by -45 (sub 2), ]s; doubled-edge-notched [0] (sub 8), laminates; and central-hole laminates. Results correlated well with the experimental data. This work was performed as a validation and benchmarking exercise of the FEAMAC/CARES program. FEAMAC/CARES simulates stochastic-based discrete-event progressive damage of ceramic matrix composite and polymer matrix composite material structures. It couples three software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/Life), and (3) the Abaqus finite element analysis program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating-unit-cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC, and Abaqus is used to model the overall composite structure. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events that incrementally progress until ultimate structural failure.

  17. Strengthening Your Surgical Hand: Strengths-Based Profiling and Coaching of Surgical Trainees

    Directory of Open Access Journals (Sweden)

    D.A.L. Macafee

    2012-01-01

    Full Text Available Introduction As scientific and professional disciplines, medicine and surgery have a tendency to focus on deficiencies, namely what trainees do not know or are not good at doing. The philosophy of Positive Psychology and the notion of “Strengths” takes a different stance. It is an inherently positive process, seeing each trainee as an individual bringing a unique set of strengths to every situation. There is clear evidence from the commercial sector regarding improved performance and well-being when focusing on one's strengths. We were therefore keen to investigate its potential role in the global development of trainee surgeons. Methods Surgical trainees from Core Training 1 to Specialty Training 8 in one training region of the United Kingdom were invited to voluntarily undertake the online Strengthscope™ assessment tool. The computer-generated report was reviewed by an Occupational Psychologist and trainees were then invited to have a strengths-focused feedback discussion on that report, either face-to-face or via telephone. Results Thirty four surgical trainees ranging from CT1 to ST6 completed the tool and 28 undertook the voluntary feedback sessions. Decisiveness, self-improvement, efficiency, emotional control and critical thinking were common strengths identified. Less commonly represented were leading, creativity and developing others. Trainees found that the tool and feedback helped them identify their strengths and embrace them, rather than fitting the surgical mould. It further aided the recognition of strengths in-overdrive and for some trainees it helped explain difficulties they had experienced in previous jobs. It provided insight into individual motivations and character whilst also highlighting how others in the workplace might perceive them. Trainees liked the emphasis on the building up of positive attributes and utilizing innate skills and strengths. The feedback consultation from an accredited coach trained in the

  18. Artificial Neural Network-Based Early-Age Concrete Strength Monitoring Using Dynamic Response Signals.

    Science.gov (United States)

    Kim, Junkyeong; Lee, Chaggil; Park, Seunghee

    2017-06-07

    Concrete is one of the most common materials used to construct a variety of civil infrastructures. However, since concrete might be susceptible to brittle fracture, it is essential to confirm the strength of concrete at the early-age stage of the curing process to prevent unexpected collapse. To address this issue, this study proposes a novel method to estimate the early-age strength of concrete, by integrating an artificial neural network algorithm with a dynamic response measurement of the concrete material. The dynamic response signals of the concrete, including both electromechanical impedances and guided ultrasonic waves, are obtained from an embedded piezoelectric sensor module. The cross-correlation coefficient of the electromechanical impedance signals and the amplitude of the guided ultrasonic wave signals are selected to quantify the variation in dynamic responses according to the strength of the concrete. Furthermore, an artificial neural network algorithm is used to verify a relationship between the variation in dynamic response signals and concrete strength. The results of an experimental study confirm that the proposed approach can be effectively applied to estimate the strength of concrete material from the early-age stage of the curing process.

  19. Multiple linear regression to develop strength scaled equations for knee and elbow joints based on age, gender and segment mass

    DEFF Research Database (Denmark)

    D'Souza, Sonia; Rasmussen, John; Schwirtz, Ansgar

    2012-01-01

    and valuable ergonomic tool. Objective: To investigate age and gender effects on the torque-producing ability in the knee and elbow in older adults. To create strength scaled equations based on age, gender, upper/lower limb lengths and masses using multiple linear regression. To reduce the number of dependent...... flexors. Results: Males were signifantly stronger than females across all age groups. Elbow peak torque (EPT) was better preserved from 60s to 70s whereas knee peak torque (KPT) reduced significantly (PGender, thigh mass and age best...... predicted KPT (R2=0.60). Gender, forearm mass and age best predicted EPT (R2=0.75). Good crossvalidation was established for both elbow and knee models. Conclusion: This cross-sectional study of muscle strength created and validated strength scaled equations of EPT and KPT using only gender, segment mass...

  20. Comparative evaluation of tensile bond strength of silicone-based denture liners after thermocycling and surface treatment.

    Science.gov (United States)

    Kaur, Harsimran; Datta, Kusum

    2015-01-01

    To examine, evaluate, and compare the tensile bond strength of two silicone-based liners; one autopolymerizing and one heat cured, when treated with different chemical etchants to improve their adhesion with denture base resin. Hundred and sixty test specimens of heat-cured polymethyl methacrylate (PMMA) were fabricated; out of which 80 specimens were tested for tensile bond strength after bonding it to autopolymerizing resilient liner (Ufigel P) and rest 80 to heat-cured resilient liner (Molloplast B). Each main group was further divided into four subgroups of 20 specimens each, one to act as a control and three were subjected to surface treatment with different chemical etchants namely dichloromethane, MMA monomer, and chloroform. The two silicone-based denture liners were processed between 2 PMMA specimens (10 mm × 10 mm × 40 mm) in the space provided by a spacer of 3 mm, thermocycled (5-55°C) for 500 cycles, and then their tensile strength measurements were done in the universal testing machine. One-way ANOVA technique showed a highly significant difference in the mean tensile bond strength values for all the groups. The Student's t-test computed values of statistics for the compared groups were greater than the critical values both at 5% and at 1% levels. Surface treatment of denture base resin with chemical etchants prior to the application of silicone-based liner (Ufigel P and Molloplast-B) increased the tensile bond strength. The increase was the highest with specimens subjected to 180 s of MMA surface treatment and the lowest with control group specimens.

  1. Comparative evaluation of tensile bond strength of silicone-based denture liners after thermocycling and surface treatment

    Directory of Open Access Journals (Sweden)

    Harsimran Kaur

    2015-01-01

    Full Text Available Purpose: To examine, evaluate, and compare the tensile bond strength of two silicone-based liners; one autopolymerizing and one heat cured, when treated with different chemical etchants to improve their adhesion with denture base resin. Materials and Methods: Hundred and sixty test specimens of heat-cured polymethyl methacrylate (PMMA were fabricated; out of which 80 specimens were tested for tensile bond strength after bonding it to autopolymerizing resilient liner (Ufigel P and rest 80 to heat-cured resilient liner (Molloplast B. Each main group was further divided into four subgroups of 20 specimens each, one to act as a control and three were subjected to surface treatment with different chemical etchants namely dichloromethane, MMA monomer, and chloroform. The two silicone-based denture liners were processed between 2 PMMA specimens (10 mm × 10 mm × 40 mm in the space provided by a spacer of 3 mm, thermocycled (5-55°C for 500 cycles, and then their tensile strength measurements were done in the universal testing machine. Results: One-way ANOVA technique showed a highly significant difference in the mean tensile bond strength values for all the groups. The Student′s t-test computed values of statistics for the compared groups were greater than the critical values both at 5% and at 1% levels. Conclusion: Surface treatment of denture base resin with chemical etchants prior to the application of silicone-based liner (Ufigel P and Molloplast-B increased the tensile bond strength. The increase was the highest with specimens subjected to 180 s of MMA surface treatment and the lowest with control group specimens.

  2. Effect of surface treatments on the bond strength of soft denture lining materials to an acrylic resin denture base.

    Science.gov (United States)

    Gundogdu, Mustafa; Yesil Duymus, Zeynep; Alkurt, Murat

    2014-10-01

    Adhesive failure between acrylic resin and resilient liner material is commonly encountered in clinical practice. The purpose of this study was to evaluate the effect of different surface treatments on the bond strength of 2 different resilient lining materials to an acrylic resin denture base. Ninety-six dumbbell-shaped specimens were fabricated from heat-polymerized acrylic resin, and 3 mm of the material was cut from the thin midsection. The specimens were divided into 6 groups according to their surface treatments: no surface treatment (control group), 36% phosphoric acid etching (acid group), erbium:yttrium-aluminum-garnet (Er:YAG) laser (laser group), airborne-particle abrasion with 50-μm Al2O3 particles (abrasion group), an acid+laser group, and an abrasion+laser group. The specimens in each group were divided into 2 subgroups according to the resilient lining material used: heat-polymerized silicone based resilient liner (Molloplast B) and autopolymerized silicone-based resilient liner (Ufi Gel P). After all of the specimens had been polymerized, they were stored in distilled water at 37°C for 1 week. A tensile bond strength test was then performed. Data were analyzed with a 2-way ANOVA, and the Sidak multiple comparison test was used to identify significant differences (α=.05). The effects of the surface treatments and resilient lining materials on the surface of the denture base resin were examined with scanning electron microscopy. The tensile bond strength was significantly different between Molloplast B and Ufi Gel P (P<.001). The specimens of the acid group had the highest tensile bond strength, whereas those of the abrasion group had the lowest tensile bond strength. The scanning electron microscopy observations showed that the application of surface treatments modified the surface of the denture base resin. Molloplast B exhibited significantly higher bond strength than Ufi Gel P. Altering the surface of the acrylic resin denture base with 36

  3. Treatment of adolescent sexual offenders: theory-based practice.

    Science.gov (United States)

    Sermabeikian, P; Martinez, D

    1994-11-01

    The treatment of adolescent sexual offenders (ASO) has its theoretical underpinnings in social learning theory. Although social learning theory has been frequently cited in literature, a comprehensive application of this theory, as applied to practice, has not been mapped out. The social learning and social cognitive theories of Bandura appear to be particularly relevant to the group treatment of this population. The application of these theories to practice, as demonstrated in a program model, is discussed as a means of demonstrating how theory-driven practice methods can be developed.

  4. Energy-Based Yield Criteria for Orthotropic Materials, Exhibiting Strength-Differential Effect. Specification for Sheets under Plane Stress State

    Directory of Open Access Journals (Sweden)

    Szeptyński P.

    2017-06-01

    Full Text Available A general proposition of an energy-based limit condition for anisotropic materials exhibiting strength-differential effect (SDE based on spectral decomposition of elasticity tensors and the use of scaling pressure-dependent functions is specified for the case of orthotropic materials. A detailed algorithm (based on classical solutions of cubic equations for the determination of elastic eigenstates and eigenvalues of the orthotropic stiffness tensor is presented. A yield condition is formulated for both two-dimensional and three-dimensional cases. Explicit formulas based on simple strength tests are derived for parameters of criterion in the plane case. The application of both criteria for the description of yielding and plastic deformation of metal sheets is discussed in detail. The plane case criterion is verified with experimental results from the literature.

  5. Adhesion strength of nickel and zinc coatings with copper base electroplated in conditions of external stimulation by laser irradiance

    Directory of Open Access Journals (Sweden)

    V. V. Dudkina

    2013-04-01

    Full Text Available Purpose. The investigation of laser irradiance influence on the adhesion strength of nickel and zinc coatings with copper base and the research of initial stages of crystallization for nickel and zinc films. Methodology. Electrodeposition of nickel and zinc films from the standard sulphate electrolyte solutions was carried out on the laser-electrolytic installations, built on the basis of gas discharge CO2-laser and solid ruby laser KVANT-12. The adhesion strength of metal coatings with copper base are defined not only qualitatively using the method of meshing and by means of multiple bending, but also quantitatively by means of indention of diamond pyramid into the border line between coating and base of the side section. Spectrum microanalysis of the element composition of the border line “film and base” is carried out using the electronic microscope REMMA-102-02. Findings. Laser irradiance application of the cathode region in the process of electroplating of metal coatings enables the adhesion strength improvement of coating with the base. Experimental results of adhesive strength of the films and the spectrum analysis of the element composition for the border line between film and base showed that during laser-assisted electroplating the diffusion interaction between coating elements and the base metal surface takes place. As a result of this interaction the coating metal diffuses into the base metal, forming transition diffused layer, which enhances the improvement of adhesion strength of the coatings with the base. Originality. It is found out that ion energy increase in the double electric layer during interaction with laser irradiance affects cathode supersaturation at the stage of crystallization. Hence, it also affects the penetration depth of electroplated material ions into the base metal, which leads to the adhesion strength enhancement. Practical value. On the basis of research results obtained during the laser

  6. An IDS Alerts Aggregation Algorithm Based on Rough Set Theory

    Science.gov (United States)

    Zhang, Ru; Guo, Tao; Liu, Jianyi

    2018-03-01

    Within a system in which has been deployed several IDS, a great number of alerts can be triggered by a single security event, making real alerts harder to be found. To deal with redundant alerts, we propose a scheme based on rough set theory. In combination with basic concepts in rough set theory, the importance of attributes in alerts was calculated firstly. With the result of attributes importance, we could compute the similarity of two alerts, which will be compared with a pre-defined threshold to determine whether these two alerts can be aggregated or not. Also, time interval should be taken into consideration. Allowed time interval for different types of alerts is computed individually, since different types of alerts may have different time gap between two alerts. In the end of this paper, we apply proposed scheme on DAPRA98 dataset and the results of experiment show that our scheme can efficiently reduce the redundancy of alerts so that administrators of security system could avoid wasting time on useless alerts.

  7. Qigong in Cancer Care: Theory, Evidence-Base, and Practice

    Directory of Open Access Journals (Sweden)

    Penelope Klein

    2017-01-01

    Full Text Available Background: The purpose of this discussion is to explore the theory, evidence base, and practice of Qigong for individuals with cancer. Questions addressed are: What is qigong? How does it work? What evidence exists supporting its practice in integrative oncology? What barriers to wide-spread programming access exist? Methods: Sources for this discussion include a review of scholarly texts, the Internet, PubMed, field observations, and expert opinion. Results: Qigong is a gentle, mind/body exercise integral within Chinese medicine. Theoretical foundations include Chinese medicine energy theory, psychoneuroimmunology, the relaxation response, the meditation effect, and epigenetics. Research supports positive effects on quality of life (QOL, fatigue, immune function and cortisol levels, and cognition for individuals with cancer. There is indirect, scientific evidence suggesting that qigong practice may positively influence cancer prevention and survival. No one Qigong exercise regimen has been established as superior. Effective protocols do have common elements: slow mindful exercise, easy to learn, breath regulation, meditation, emphasis on relaxation, and energy cultivation including mental intent and self-massage. Conclusions: Regular practice of Qigong exercise therapy has the potential to improve cancer-related QOL and is indirectly linked to cancer prevention and survival. Wide-spread access to quality Qigong in cancer care programming may be challenged by the availability of existing programming and work force capacity.

  8. Influence of incorporation of ZrO2 nanoparticles on the repair strength of polymethyl methacrylate denture bases

    Directory of Open Access Journals (Sweden)

    Gad MM

    2016-10-01

    Full Text Available Mohammed M Gad,1 Ahmed Rahoma,2,3 Ahmad M Al-Thobity,1 Aws S ArRejaie4 1Department of Substitutive Dental Sciences, 2Department of Restorative Dental Sciences, College of Dentistry, University of Dammam, Dammam, Saudi Arabia; 3Department of Dental Materials, College of Dentistry, Al-Azhar University, Assiut, Egypt; 4Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia Background: Repeated fracture of the denture base is a common problem in prosthodontics, and it represents a nuisance and a time sink for the clinician. Therefore, the possibility of increasing repair strength using new reinforcement materials is of great interest to prosthodontists.Aim of the study: This study aimed to evaluate the effects of incorporation of zirconia nanoparticles (nano-ZrO2 on the flexural strength and impact strength of repaired polymethyl methacrylate (PMMA denture bases.Materials and methods: One hundred eighty specimens of heat-polymerized acrylic resin were fabricated (90 for each test and divided into three main groups: one control group (intact specimens and two groups divided according to surface design (45° bevels and butt joints, in which specimens were prepared in pairs to create 2.5 mm gaps. Nano-ZrO2 was added to repair resin in 2.5 wt%, 5 wt%, and 7.5 wt% concentrations of acrylic powder. A three-point bending test was used to measure flexural strength, and a Charpy-type test was used to measure impact strength. Scanning electron microscopy was used to analyze the fracture surfaces and nano-ZrO2 distribution. The results were analyzed with a paired sample t-test and an unpaired t-test, with a P-value of ≤0.05 being significant.Results: Incorporation of nano-ZrO2 into the repair resin significantly increased flexural strength (P<0.05. The highest value was found in the bevel group reinforced with 7.5% nano-ZrO2, whereas the lowest value was found in the butt group reinforced with 2.5% nano

  9. Historical Chronology of ENSO Events Based Upon Documentary Data From South America: Strengths and Limitations

    Science.gov (United States)

    Luc, O.

    2007-05-01

    sequence deal with the non-homogeneity of the documentary records, the reconstruction of the paleo-events strength and the difficulty to cross check documentary data with other annually resolved records (corals, tree-rings and ice-core data). In spite of all these limitations, the documentation of former EN occurrences based upon written archives from colonial South-America remains an unavoidable and powerful tool to reconstruct a solid El Niño chronology for the last half millennium and to better understand the interplay of the different modes (at the interannual, decadal, multidecadal and centennial scales) of climate variations in this part of the world.

  10. Difference in Agility, Strength, and Flexibility in Competitive Figure Skaters Based on Level of Expertise and Skating Discipline.

    Science.gov (United States)

    Slater, Lindsay V; Vriner, Melissa; Zapalo, Peter; Arbour, Kat; Hart, Joseph M

    2016-12-01

    Slater, LV, Vriner, M, Zapalo, P, Arbour, K, and Hart, JM. Difference in agility, strength, and flexibility in competitive figure skaters based on level of expertise and skating discipline. J Strength Cond Res 30(12): 3321-3328, 2016-Figure skating is an extremely difficult sport that requires a combination of grace, artistry, flexibility, speed, and power. Although many skaters are involved with strength and conditioning programs, there is no current information about differences in off-ice performance measures based on skating discipline and level. The purpose of this study was to compare agility, strength, and flexibility performance based on skating discipline and level. A total of 343 figure skaters from 4 different disciplines (singles, dance, pair, and synchronized skating) and 3 different levels (novice, junior, and senior) completed combine testing with the United States Figure Skating Association. All subjects completed the hexagon agility test, t-test, triple bound jumps, vertical jump, timed tuck jumps, push-ups, v-ups, hand press, front split, seated reach, and stork pose. A multivariate analysis of variance with Scheffe's post hoc was used to identify differences in performance based on skating discipline and level. Mean differences, Cohen's d effect sizes, and 95% confidence intervals were reported for all significant differences. Senior and junior skaters tended to be faster and stronger than novice skaters. Singles, dance, and pair skaters tended to be more agile, stronger, and flexible than synchronized skaters, however, senior synchronized skaters tended to perform better than senior skaters in other disciplines. These results indicate that strength and conditioning professionals should consider skating discipline and level when designing strengthening programs for figure skaters.

  11. A Field Experimental Design of a Strengths-Based Training to Overcome Academic Procrastination: Short- and Long-Term Effect

    Directory of Open Access Journals (Sweden)

    Lennart Visser

    2017-11-01

    Full Text Available This study reports on the effect of a newly developed 4-week strengths-based training approach to overcome academic procrastination, given to first-year elementary teacher education students (N = 54. The training was based on a strengths-based approach, in which elements of the cognitive behavioral approach were also used. The purpose of the training was to promote awareness of the personal strengths of students who experience academic procrastination regularly and to teach them how to use their personal strengths in situations in which they usually tend to procrastinate. With a pretest-posttest control group design (two experimental groups: n = 31, control group: n = 23, the effect of the training on academic procrastination was studied after 1, 11, and 24 weeks. Results of a one-way analysis of covariance revealed a significant short-term effect of the training. In the long term (after 11 and 24 weeks, the scores for academic procrastination for the intervention groups remained stable, whereas the scores for academic procrastination for the control group decreased to the same level as those of the intervention groups. The findings of this study suggest that a strengths-based approach can be helpful to students at an early stage of their academic studies to initiate their individual process of dealing with academic procrastination. The findings for the long term show the importance of measuring the outcomes of an intervention not only shortly after the intervention but also in the long term. Further research is needed to find out how the short-term effect can be maintained in the long-term.

  12. A Field Experimental Design of a Strengths-Based Training to Overcome Academic Procrastination: Short- and Long-Term Effect.

    Science.gov (United States)

    Visser, Lennart; Schoonenboom, Judith; Korthagen, Fred A J

    2017-01-01

    This study reports on the effect of a newly developed 4-week strengths-based training approach to overcome academic procrastination, given to first-year elementary teacher education students ( N = 54). The training was based on a strengths-based approach, in which elements of the cognitive behavioral approach were also used. The purpose of the training was to promote awareness of the personal strengths of students who experience academic procrastination regularly and to teach them how to use their personal strengths in situations in which they usually tend to procrastinate. With a pretest-posttest control group design (two experimental groups: n = 31, control group: n = 23), the effect of the training on academic procrastination was studied after 1, 11, and 24 weeks. Results of a one-way analysis of covariance revealed a significant short-term effect of the training. In the long term (after 11 and 24 weeks), the scores for academic procrastination for the intervention groups remained stable, whereas the scores for academic procrastination for the control group decreased to the same level as those of the intervention groups. The findings of this study suggest that a strengths-based approach can be helpful to students at an early stage of their academic studies to initiate their individual process of dealing with academic procrastination. The findings for the long term show the importance of measuring the outcomes of an intervention not only shortly after the intervention but also in the long term. Further research is needed to find out how the short-term effect can be maintained in the long-term.

  13. A Lie based 4-dimensional higher Chern-Simons theory

    Science.gov (United States)

    Zucchini, Roberto

    2016-05-01

    We present and study a model of 4-dimensional higher Chern-Simons theory, special Chern-Simons (SCS) theory, instances of which have appeared in the string literature, whose symmetry is encoded in a skeletal semistrict Lie 2-algebra constructed from a compact Lie group with non discrete center. The field content of SCS theory consists of a Lie valued 2-connection coupled to a background closed 3-form. SCS theory enjoys a large gauge and gauge for gauge symmetry organized in an infinite dimensional strict Lie 2-group. The partition function of SCS theory is simply related to that of a topological gauge theory localizing on flat connections with degree 3 second characteristic class determined by the background 3-form. Finally, SCS theory is related to a 3-dimensional special gauge theory whose 2-connection space has a natural symplectic structure with respect to which the 1-gauge transformation action is Hamiltonian, the 2-curvature map acting as moment map.

  14. The Bus Station Spacing Optimization Based on Game Theory

    Directory of Open Access Journals (Sweden)

    Changjiang Zheng

    2015-01-01

    Full Text Available With the development of city, the problem of traffic is becoming more and more serious. Developing public transportation has become the key to solving this problem in all countries. Based on the existing public transit network, how to improve the bus operation efficiency, and reduce the residents transit trip cost has become a simple and effective way to develop the public transportation. Bus stop spacing is an important factor affecting passengers’ travel time. How to set up bus stop spacing has become the key to reducing passengers’ travel time. According to comprehensive traffic survey, theoretical analysis, and summary of urban public transport characteristics, this paper analyzes the impact of bus stop spacing on passenger in-bus time cost and out-bus time cost and establishes in-bus time and out-bus time model. Finally, the paper gets the balance best station spacing by introducing the game theory.

  15. Preservation of information in Fourier theory based deconvolved nuclear spectra

    International Nuclear Information System (INIS)

    Madan, V.K.; Gopalakrishnan, K.R.; Sharma, R.C.; Rattan, S.S.

    1995-01-01

    Nuclear spectroscopy is extremely useful to the internal radiation dosimetry for the estimation of body burden due to gamma emitters. Analysis of nuclear spectra is concerned with the extraction of qualitative and quantitative information embedded in the spectra. A spectral deconvolution method based on Fourier theory is probably the simplest method of deconvolving nuclear spectra. It is proved mathematically that the deconvolution method preserves the qualitative information. It is shown by using simulated spectra and an observed gamma ray spectrum that the method preserves the quantitative information. This may provide a novel approach of information extraction from a deconvolved spectrum. The paper discusses the methodology, mathematical analysis, and the results obtained by deconvolving spectra. (author). 6 refs., 2 tabs

  16. Novel welding image processing method based on fractal theory

    Institute of Scientific and Technical Information of China (English)

    陈强; 孙振国; 肖勇; 路井荣

    2002-01-01

    Computer vision has come into used in the fields of welding process control and automation. In order to improve precision and rapidity of welding image processing, a novel method based on fractal theory has been put forward in this paper. Compared with traditional methods, the image is preliminarily processed in the macroscopic regions then thoroughly analyzed in the microscopic regions in the new method. With which, an image is divided up to some regions according to the different fractal characters of image edge, and the fuzzy regions including image edges are detected out, then image edges are identified with Sobel operator and curved by LSM (Lease Square Method). Since the data to be processed have been decreased and the noise of image has been reduced, it has been testified through experiments that edges of weld seam or weld pool could be recognized correctly and quickly.

  17. A Lyapunov theory based UPFC controller for power flow control

    Energy Technology Data Exchange (ETDEWEB)

    Zangeneh, Ali; Kazemi, Ahad; Hajatipour, Majid; Jadid, Shahram [Center of Excellence for Power Systems Automation and Operation, Iran University of Science and Technology, Tehran (Iran)

    2009-09-15

    Unified power flow controller (UPFC) is the most comprehensive multivariable device among the FACTS controllers. Capability of power flow control is the most important responsibility of UPFC. According to high importance of power flow control in transmission lines, the proper controller should be robust against uncertainty and disturbance and also have suitable settling time. For this purpose, a new controller is designed based on the Lyapunov theory and its stability is also evaluated. The Main goal of this paper is to design a controller which enables a power system to track reference signals precisely and to be robust in the presence of uncertainty of system parameters and disturbances. The performance of the proposed controller is simulated on a two bus test system and compared with a conventional PI controller. The simulation results show the power and accuracy of the proposed controller. (author)

  18. Market Mechanism Design for Renewable Energy based on Risk Theory

    Science.gov (United States)

    Yang, Wu; Bo, Wang; Jichun, Liu; Wenjiao, Zai; Pingliang, Zeng; Haobo, Shi

    2018-02-01

    Generation trading between renewable energy and thermal power is an efficient market means for transforming supply structure of electric power into sustainable development pattern. But the trading is hampered by the output fluctuations of renewable energy and the cost differences between renewable energy and thermal power at present. In this paper, the external environmental cost (EEC) is defined and the EEC is introduced into the generation cost. At same time, the incentive functions of renewable energy and low-emission thermal power are designed, which are decreasing functions of EEC. On these bases, for the market risks caused by the random variability of EEC, the decision-making model of generation trading between renewable energy and thermal power is constructed according to the risk theory. The feasibility and effectiveness of the proposed model are verified by simulation results.

  19. Effectiveness of water-based Liuzijue exercise on respiratory muscle strength and peripheral skeletal muscle function in patients with COPD

    Directory of Open Access Journals (Sweden)

    Wu W

    2018-05-01

    Full Text Available Weibing Wu,1,* Xiaodan Liu,2,* Jingxin Liu,1 Peijun Li,1 Zhenwei Wang3 1Department of Sports Medicine, Shanghai University of Sport, 2School of Rehabilitation Medicine, Shanghai University of Traditional Chinese Medicine, 3Department of Respiratory Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai, People’s Republic of China *These authors contributed equally to this work Objects: The purpose of this study was to quantitatively assess the effects of water-based Liuzijue exercise on patients with COPD and compare it with land-based Liuzijue exercise.Materials and methods: Participants were randomly allocated to one of three groups: the water-based Liuzijue exercise group (WG, the land-based Liuzijue exercise group (LG, and the control group (CG. CG participants accepted no exercise intervention, while training groups performed Liuzijue exercise according to Health Qigong Liuzijue (People’s Republic of China in different environments for 60-min sessions twice a week for 3 months.Results: Of the 50 patients enrolled, 45 (90% completed the 3-month intervention. The CG showed decreased expiratory muscle strength, extensor and flexor endurance ratio (ER of the elbow joints and flexor peak torque (PT, total work (TW, and ER of the knee joints (p<0.05. Both training groups showed improved respiratory muscle strength, which differed from the CG (p<0.001. In addition, extensor and flexor TW of the elbow joints in the training groups were increased (p<0.01, and the WG differed from the CG in extensor TW and ER and flexor TW (p<0.01, while the LG differed from the CG in flexor TW and extensor ER (p<0.05. PT, PT/body weight (BW, and TW in the knee joint extensor in the training groups were increased as well (PT and PT/BW: p<0.05, TW: p<0.01, and the WG differed from the CG in terms of knee joints outcomes, while the LG differed from the CG in flexor TW only (p<0.05.Conclusion: Water-based Liuzijue exercise has

  20. Language Skills of Bidialectal and Bilingual Children: Considering a Strengths-Based Perspective

    Science.gov (United States)

    Lee-James, Ryan; Washington, Julie A.

    2018-01-01

    This article examines the language and cognitive skills of bidialectal and bilingual children, focusing on African American English bidialectal speakers and Spanish-English bilingual speakers. It contributes to the discussion by considering two themes in the extant literature: (1) linguistic and cognitive strengths can be found in speaking two…

  1. Performance of SOPPA-based methods in the calculation of vertical excitation energies and oscillator strengths

    DEFF Research Database (Denmark)

    Sauer, Stephan P. A.; Pitzner-Frydendahl, Henrik Frank; Buse, Mogens

    2015-01-01

    methods, the original SOPPA method as well as SOPPA(CCSD) and RPA(D) in the calculation of vertical electronic excitation energies and oscillator strengths is investigated for a large benchmark set of 28 medium-size molecules with 139 singlet and 71 triplet excited states. The results are compared...

  2. Ni.sub.3 Al-based intermetallic alloys having improved strength above 850.degree. C.

    Science.gov (United States)

    Liu, Chain T.

    2000-01-01

    Intermetallic alloys composed essentially of: 15.5% to 17.0% Al, 3.5% to 5.5% Mo, 4% to 8% Cr, 0.04% to 0.2% Zr, 0.04% to 1.5% B, balance Ni, are characterized by melting points above 1200.degree. C. and superior strengths at temperatures above 1000.degree. C.

  3. Development and Validation of a Rule-Based Strength Scaling Method for Musculoskeletal Modelling

    DEFF Research Database (Denmark)

    Oomen, Pieter; Annegarn, Janneke; Rasmussen, John

    2015-01-01

    performed maximal isometric knee extensions. A multiple linear regression analysis (MLR) resulted in an empirical strength scaling equation, accounting for age, mass, height, gender, segment masses and segment lengths. For validation purpose, 20 newly included healthy subjects performed a maximal isometric...

  4. Optimum mix for fly ash geopolymer binder based on workability and compressive strength

    Science.gov (United States)

    Arafa, S. A.; Ali, A. Z. M.; Awal, A. S. M. A.; Loon, L. Y.

    2018-04-01

    The request of concrete is increasing every day for sustaining the necessity of development of structure. The production of OPC not only consumes big amount of natural resources and energy, but also emit significant quantity of CO2 to the atmosphere. Therefore, it is necessary to find alternatives like Geopolymer to make the concrete environment friendly. Geopolymer is an inorganic alumino-silicate compound, produced from fly ash. This paper describes the experimental work conducted by casting 40 geopolymer paste mixes, and was cured at 80°C for 24 h to evaluate the effect of various parameters affecting the workability and compressive strength. Alkaline solution to fly ash ratio and sodium hydroxide (NaOH) concentration were chosen as the key parameters of strength and workability. Laboratory investigation with different percentage of sodium hydroxide concentration and different alkaline liquid to fly ash ratio reveals that the optimum ratios are 10 M, AL/FA=0.5. It has generally been found that the workability decreased and the compressive strength increased with an increase in the concentration of sodium hydroxide solution. However, workability was increased and the compressive strength was decreased with the increase in the ratio of fly ash to alkaline solution.

  5. Evaluation of Impact Strength of Epoxy Based Hybrid Composites Reinforced with E-Glass/Kevlar 49

    Directory of Open Access Journals (Sweden)

    SUBHAN ALIJOGI

    2017-10-01

    Full Text Available In hybridization different fibers are stacked layer by layer to produce laminates have specific strength and stiffness and employed in light weight high strength applications. Physically mean fabricated hybrid composites used in aerospace, under water, body armors and armed forces establishment. In present work drop-weight impact response of hybrid composites were investigated by making laminates of hybrid composites. In Hybridization layers of E-glass (roving and Kevlar 49 fabrics stacked with epoxy resin. The layers formulation was set up by hand layup method. Impregnationsof epoxy resin of commercial grade (601A in fabrics were accomplished by VRTM (Vacuum Bagging Resin Transfer Molding technique. Layup placementof Glass fibers/ Kevlar at 0°/90°, 45°/45° and 30°/60° were set for this work. Mechanical properties such as impact strength, bear resistance and break resistance were analyzed by usingASTM D-256 and D-3763 standard.Experimental investigation was conducted using instrumented Dart impact and Izod Impact test. E-glass/Kevlar 49 at layup 0°/90°and 30°/60°exhibited improvedimpact strength than 45°/45°. The surface morphology and fractography were also investigated by capturing different images of Specimens by using the SEM (Scanning Electron Microscopy. The fiberreinforcement and matrix fracture were also observed by using SEM.The SEM images suggest that epoxy resin tightly bonded with Kevlar fibers whereas Glass fibers were pulled out from laminations.

  6. Evaluation of impact strength of epoxy based hybrid composites reinforced with e-glass/kevlar 49

    International Nuclear Information System (INIS)

    Jogi, S.A.; Memon, I.A.; Baloch, M.; Chandio, A.D.

    2017-01-01

    In hybridization different fibers are stacked layer by layer to produce laminates have specific strength and stiffness and employed in light weight high strength applications. Physically mean fabricated hybrid composites used in aerospace, under water, body armors and armed forces establishment. In present work drop-weight impact response of hybrid composites were investigated by making laminates of hybrid composites. In Hybridization layers of E-glass (roving) and Kevlar 49 fabrics stacked with epoxy resin. The layers formulation was set up by hand layup method. Impregnations of epoxy resin of commercial grade (601A) in fabrics were accomplished by VRTM (Vacuum Bagging Resin Transfer Molding) technique. Layup placementof Glass fibers/ Kevlar at 0 degree/90 degree, 45 degree/45 degree and 30 degree/60 degree were set for this work. Mechanical properties such as impact strength, bear resistance and break resistance were analyzed by using ASTM D-256 and D-3763 standard. Experimental investigation was conducted using instrumented Dart impact and Izod Impact test. E-glass/Kevlar 49 at layup 0 degree/90 degree and 30 degree/60 degree exhibited improvedimpact strength than 45 degree/45 degree. The surface morphology and fractography were also investigated by capturing different images of Specimens by using the SEM (Scanning Electron Microscopy). The fiberreinforcement and matrix fracture were also observed by using SEM.The SEM images suggest that epoxy resin tightly bonded with Kevlar fibers whereas Glass fibers were pulled out from laminations. (author)

  7. High strength nanostructured Al-based alloys through optimized processing of rapidly quenched amorphous precursors.

    Science.gov (United States)

    Kim, Song-Yi; Lee, Gwang-Yeob; Park, Gyu-Hyeon; Kim, Hyeon-Ah; Lee, A-Young; Scudino, Sergio; Prashanth, Konda Gokuldoss; Kim, Do-Hyang; Eckert, Jürgen; Lee, Min-Ha

    2018-01-18

    We report the methods increasing both strength and ductility of aluminum alloys transformed from amorphous precursor. The mechanical properties of bulk samples produced by spark-plasma sintering (SPS) of amorphous Al-Ni-Co-Dy powders at temperatures above 673 K are significantly enhanced by in-situ crystallization of nano-scale intermetallic compounds during the SPS process. The spark plasma sintered Al 84 Ni 7 Co 3 Dy 6 bulk specimens exhibit 1433 MPa compressive yield strength and 1773 MPa maximum strength together with 5.6% plastic strain, respectively. The addition of Dy enhances the thermal stability of primary fcc Al in the amorphous Al-TM -RE alloy. The precipitation of intermetallic phases by crystallization of the remaining amorphous matrix plays important role to restrict the growth of the fcc Al phase and contributes to the improvement of the mechanical properties. Such fully crystalline nano- or ultrafine-scale Al-Ni-Co-Dy systems are considered promising for industrial application because their superior mechanical properties in terms of a combination of very high room temperature strength combined with good ductility.

  8. Reliability, Validity, and Sensitivity of a Novel Smartphone-Based Eccentric Hamstring Strength Test in Professional Football Players.

    Science.gov (United States)

    Lee, Justin W Y; Cai, Ming-Jing; Yung, Patrick S H; Chan, Kai-Ming

    2018-05-01

    To evaluate the test-retest reliability, sensitivity, and concurrent validity of a smartphone-based method for assessing eccentric hamstring strength among male professional football players. A total of 25 healthy male professional football players performed the Chinese University of Hong Kong (CUHK) Nordic break-point test, hamstring fatigue protocol, and isokinetic hamstring strength test. The CUHK Nordic break-point test is based on a Nordic hamstring exercise. The Nordic break-point angle was defined as the maximum point where the participant could no longer support the weight of his body against gravity. The criterion for the sensitivity test was the presprinting and postsprinting difference of the Nordic break-point angle with a hamstring fatigue protocol. The hamstring fatigue protocol consists of 12 repetitions of the 30-m sprint with 30-s recoveries between sprints. Hamstring peak torque of the isokinetic hamstring strength test was used as the criterion for validity. A high test-retest reliability (intraclass correlation coefficient = .94; 95% confidence interval, .82-.98) was found in the Nordic break-point angle measurements. The Nordic break-point angle significantly correlated with isokinetic hamstring peak torques at eccentric action of 30°/s (r = .88, r 2  = .77, P hamstring strength measures among male professional football players.

  9. Fracture Strength of Aged Monolithic and Bilayer Zirconia-Based Crowns

    Directory of Open Access Journals (Sweden)

    Deborah Pacheco Lameira

    2015-01-01

    Full Text Available The purpose of this study was to evaluate the effect of design and surface finishing on fracture strength of yttria-tetragonal zirconia polycrystal (Y-TZP crowns in monolithic (1.5 mm thickness and bilayer (0.8 mm zirconia coping and 0.7 mm porcelain veneer configuration after artificial aging. Bovine incisors received crown preparation and Y-TZP crowns were manufactured using CAD/CAM technique, according to the following groups (n=10: Polished monolithic zirconia crowns (PM; Glazed monolithic zirconia crowns (GM; Bi-layer crowns (BL. Crowns were cemented with resin cement, submitted to artificial aging in a chewing simulator (2.5 million cycles/80 N/artificial saliva/37°C, and tested for fracture strength. Two remaining crowns referring to PM and GM groups were submitted to a chemical composition analysis to measure the level of yttrium after aging. One-way ANOVA and Tukey’s test (P=.05 indicated that monolithic zirconia crowns presented similar fracture strength (PM=3476.2 N ± 791.7; GM=3561.5 N ± 991.6, which was higher than bilayer crowns (2060.4 N ± 810.6. There was no difference in the yttrium content among the three surfaces evaluated in the monolithic crowns. Thus, monolithic zirconia crowns present higher fracture strength than bilayer veneered zirconia after artificial aging and surface finishing does not affect their fracture strength.

  10. Reliability, failure probability, and strength of resin-based materials for CAD/CAM restorations

    Directory of Open Access Journals (Sweden)

    Kiatlin Lim

    Full Text Available ABSTRACT Objective: This study investigated the Weibull parameters and 5% fracture probability of direct, indirect composites, and CAD/CAM composites. Material and Methods: Discshaped (12 mm diameter x 1 mm thick specimens were prepared for a direct composite [Z100 (ZO, 3M-ESPE], an indirect laboratory composite [Ceramage (CM, Shofu], and two CAD/CAM composites [Lava Ultimate (LU, 3M ESPE; Vita Enamic (VE, Vita Zahnfabrik] restorations (n=30 for each group. The specimens were polished, stored in distilled water for 24 hours at 37°C. Weibull parameters (m= modulus of Weibull, σ0= characteristic strength and flexural strength for 5% fracture probability (σ5% were determined using a piston-on-three-balls device at 1 MPa/s in distilled water. Statistical analysis for biaxial flexural strength analysis were performed either by both one-way ANOVA and Tukey's post hoc (α=0.05 or by Pearson's correlation test. Results: Ranking of m was: VE (19.5, LU (14.5, CM (11.7, and ZO (9.6. Ranking of σ0 (MPa was: LU (218.1, ZO (210.4, CM (209.0, and VE (126.5. σ5% (MPa was 177.9 for LU, 163.2 for CM, 154.7 for Z0, and 108.7 for VE. There was no significant difference in the m for ZO, CM, and LU. VE presented the highest m value and significantly higher than ZO. For σ0 and σ5%, ZO, CM, and LU were similar but higher than VE. Conclusion: The strength characteristics of CAD/ CAM composites vary according to their composition and microstructure. VE presented the lowest strength and highest Weibull modulus among the materials.

  11. Learning Styles of Baccalaureate Nursing Students and Attitudes toward Theory-Based Nursing.

    Science.gov (United States)

    Laschinger, Heather K.; Boss, Marvin K.

    1989-01-01

    The personal and environmental factors related to undergraduate and post-RN nursing students' attitudes toward theory-based nursing from Kolb's experiential learning theory perspective were investigated. Learning style and environmental press perceptions were found to be related to attitudes toward theory-based nursing. (Author/MLW)

  12. Critical Theory-Based Approaches in Geography Teaching Departments in Turkey

    Science.gov (United States)

    Bilgili, Münür

    2018-01-01

    The aim of this study is to understand the relationships between critical theory-based approaches and its implementations in geography teaching departments in Turkey. Critical theory dates back to 1930s and has developed over time aiming to deal with institutions, culture and society through critical lens. Currently, critical theory-based research…

  13. Influence of Graphene Nanosheets on Rheology, Microstructure, Strength Development and Self-Sensing Properties of Cement Based Composites

    Directory of Open Access Journals (Sweden)

    Sardar Kashif Ur Rehman

    2018-03-01

    Full Text Available In this research, Graphene oxide (GO, prepared by modified hammer method, is characterized using X-ray Diffraction (XRD, Fourier Transform Infrared (FT-IR Spectrometry and Raman spectra. The dispersion efficiency of GO in aqueous solution is examined by Ultraviolet–visible spectroscopy and it is found that GO sheets are well dispersed. Thereafter, rheological properties, flow diameter, hardened density, compressive strength and electrical properties of GO based cement composite are investigated by incorporating 0.03% GO in cement matrix. The reasons for improvement in strength are also discussed. Rheological results confirm that GO influenced the flow behavior and enhanced the viscosity of the cement based system. From XRD and Thermogravimetric Analysis (TGA results, it is found that more hydration occurred when GO was incorporated in cement based composite. The GO based cement composite improves the compressive strength and density of mortar by 27% and 1.43%, respectively. Electrical properties results showed that GO–cement based composite possesses self-sensing characteristics. Hence, GO is a potential nano-reinforcement candidate and can be used as self-sensing sustainable construction material.

  14. Evolutionary game theory using agent-based methods.

    Science.gov (United States)

    Adami, Christoph; Schossau, Jory; Hintze, Arend

    2016-12-01

    Evolutionary game theory is a successful mathematical framework geared towards understanding the selective pressures that affect the evolution of the strategies of agents engaged in interactions with potential conflicts. While a mathematical treatment of the costs and benefits of decisions can predict the optimal strategy in simple settings, more realistic settings such as finite populations, non-vanishing mutations rates, stochastic decisions, communication between agents, and spatial interactions, require agent-based methods where each agent is modeled as an individual, carries its own genes that determine its decisions, and where the evolutionary outcome can only be ascertained by evolving the population of agents forward in time. While highlighting standard mathematical results, we compare those to agent-based methods that can go beyond the limitations of equations and simulate the complexity of heterogeneous populations and an ever-changing set of interactors. We conclude that agent-based methods can predict evolutionary outcomes where purely mathematical treatments cannot tread (for example in the weak selection-strong mutation limit), but that mathematics is crucial to validate the computational simulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. The Operation Method of Smarter City Based on Ecological Theory

    Science.gov (United States)

    Fan, C.; Fan, H. Y.

    2017-10-01

    As the city and urbanization’s accelerated pace has caused galloping population, the urban framework is extending with increasingly complex social problems. The urban management tends to become complicated and the governance seems more difficult to pursue. exploring the urban management’s new model has attracted local governments’ urgent attention. tcombines the guiding ideology and that management’s practices based on ecological theory, explains the Smarter city Ecology Managementmodel’s formation, makes modern urban management’s comparative analysis and further defines the aforesaid management mode’s conceptual model. Based on the smarter city system theory’s ecological carrying capacity, the author uses mathematical model to prove the coordination relationship between the smarter city Ecology Managementmode’s subsystems, demonstrates that it can improve the urban management’s overall level, emphasizes smarter city management integrity, believing that urban system’s optimization is based on each subsystem being optimized, attaching the importance to elements, structure, and balance between each subsystem and between internal elements. Through the establishment of the smarter city Ecology Managementmodel’s conceptual model and theoretical argumentation, it provides a theoretical basis and technical guidance to that model’s innovation.

  16. Evaluation of the strengths and weaknesses of community-based education from the viewpoint of students

    Directory of Open Access Journals (Sweden)

    SEDIGHEH MOKHTARPOUR

    2016-10-01

    Full Text Available Introduction: Responsive medicine is an appropriate training method which trains the graduates who can act effectively in initial and secondary aspects of health issues in the society. Methods: This was a cross-sectional descriptive-analytic study which was done using quantitative method. The target population of this study was all the students of the Nutrition and Health School of Shiraz University of Medical Sciences. The sample was randomly selected in this study and 75 students were selected based on the methodologist’s comments and similar studies and randomnumber table from a list obtained from the school’s department of education. This questionnaire was a researcher-made one which consisted of 23 questions in 2 sections with 21 closedended questions and 2 open-ended questions; 70 questionnaires were completed correctly. The closed-ended questions had 4 aspects (completely agree to completely disagree answered in 5-point Likert scale type. Its face validity was confirmed by 4 faculty members. The construct validity of the questionnaire was analyzed by factor analysis test and its reliability was assessed by a pilot on 20 students with a Cronbach’s alpha of 0.85. The data were analyzed using descriptive statistical tests (mean, standard deviation, … and the Pearson coefficient (p<0.001. Results: The results of this study showed that the maximum mean score was 3.58±0.65 which was related to the context of these courses and the minimum mean was 2.66±1.14 which was related to the logbook implementation. The 2 open-ended questions indicated that the most important strengths were the use of logbooks as a guide and determining the minimum training; of the weaknesses was the mismatch between the theoretical education and the practical activities. Also, developing the minimum training that an expert should know and using the common topics related to theoretical education were the most important points mentioned by the respondents

  17. A density functional theory-based chemical potential equalisation ...

    Indian Academy of Sciences (India)

    Unknown

    ties both of which can be calculated through the evaluation of ... used widely for the understanding of chemical binding, reactivity ... lent binding. There have ..... where ε represents a measure of the dielectric con- stant of the ..... field strength.

  18. Nonlinear modeling, strength-based design, and testing of flexible piezoelectric energy harvesters under large dynamic loads for rotorcraft applications

    Science.gov (United States)

    Leadenham, Stephen; Erturk, Alper

    2014-04-01

    There has been growing interest in enabling wireless health and usage monitoring for rotorcraft applications, such as helicopter rotor systems. Large dynamic loads and acceleration fluctuations available in these environments make the implementation of vibration-based piezoelectric energy harvesters a very promising choice. However, such extreme loads transmitted to the harvester can also be detrimental to piezoelectric laminates and overall system reliability. Particularly flexible resonant cantilever configurations tuned to match the dominant excitation frequency can be subject to very large deformations and failure of brittle piezoelectric laminates due to excessive bending stresses at the root of the harvester. Design of resonant piezoelectric energy harvesters for use in these environments require nonlinear electroelastic dynamic modeling and strength-based analysis to maximize the power output while ensuring that the harvester is still functional. This paper presents a mathematical framework to design and analyze the dynamics of nonlinear flexible piezoelectric energy harvesters under large base acceleration levels. A strength-based limit is imposed to design the piezoelectric energy harvester with a proof mass while accounting for material, geometric, and dissipative nonlinearities, with a focus on two demonstrative case studies having the same linear fundamental resonance frequency but different overhang length and proof mass values. Experiments are conducted at different excitation levels for validation of the nonlinear design approach proposed in this work. The case studies in this work reveal that harvesters exhibiting similar behavior and power generation performance at low excitation levels (e.g. less than 0.1g) can have totally different strength-imposed performance limitations under high excitations (e.g. above 1g). Nonlinear modeling and strength-based design is necessary for such excitation levels especially when using resonant cantilevers with no

  19. Evaluation of bond strength of silorane and methacrylate based restorative systems to dentin using different cavity models

    Directory of Open Access Journals (Sweden)

    Stephano Zerlottini Isaac

    2013-09-01

    Full Text Available OBJECTIVE: The aim of this in vitro study was to evaluate the microtensile bond strength (µTBS to dentin of two different restorative systems: silorane-based (P90, and methacrylate-based (P60, using two cavity models. MATERIAL AND METHODS: Occlusal enamel of 40 human third molars was removed to expose flat dentin surface. Class I cavities with 4 mm mesial-distal width, 3 mm buccal-lingual width and 3 mm depth (C-factor=4.5 were prepared in 20 teeth, which were divided into two groups (n=10 restored with P60 and P90, bulk-filled after dentin treatment according to manufacturer's instructions. Flat buccal dentin surfaces were prepared in the 20 remaining teeth (C-factor=0.2 and restored with resin blocks measuring 4x3x3 mm using the two restorative systems (n=10. The teeth were sectioned into samples with area between 0.85 and 1.25 mm2 that were submitted to µTBS testing, using a universal testing machine (EMIC at speed of 0.5 mm/min. Fractured specimens were analyzed under stereomicroscope and categorized according to fracture pattern. Data were analyzed using ANOVA and Tukey Kramer tests. RESULTS: For flat surfaces, P60 obtained higher bond strength values compared with P90. However, for Class I cavities, P60 showed significant reduction in bond strength (p0.05, or between Class I Cavity and Flat Surface group, considering P90 restorative system (p>0.05. Regarding fracture pattern, there was no statistical difference among groups (p=0.0713 and 56.3% of the fractures were adhesive. CONCLUSION: It was concluded that methacrylate-based composite µTBS was influenced by cavity models, and the use of silorane-based composite led to similar bond strength values compared to the methacrylate-based composite in cavities with high C-factor.

  20. Investigation of the effect of base strength on the antifungal activity and chemical composition of the fish scales hydrolyzates

    International Nuclear Information System (INIS)

    Niaz, S.; Dil, S.

    2016-01-01

    The effect of base strength on the antifungal activity of the fish scale hydrolyzate was investigated for six types of samples prepared from the scales of Cyprinus carpio using sodium hydroxide in the range of 1-11 percent strength in the aqueous solution. Each of the sample was analyzed for its acid-base content using titration against HCl in addition to the spot test analysis for phenolic compounds. Each of these samples was analyzed using FTIR spectroscopy. Variation in chemical composition and functional group were observed with variation in the base strength. The in vitro antifungal activity of the fish scale hydrolyzates was tested against four pathogenic fungi including Acremonium, Pythium, Verticillium, and Alternaria. The antifungal assay was carried out using agar well diffusion methods. The sterilization was carried out using streptomycin while ketoconazole was used as the standard antifungal agent. Minimum inhibitory concentration was determined for the most active hydrolyzate which was obtained by 9 percent base solution. The cause of this antifungal activity was also discussed in this communication. (author)

  1. Discovery and validation of information theory-based transcription factor and cofactor binding site motifs.

    Science.gov (United States)

    Lu, Ruipeng; Mucaki, Eliseos J; Rogan, Peter K

    2017-03-17

    Data from ChIP-seq experiments can derive the genome-wide binding specificities of transcription factors (TFs) and other regulatory proteins. We analyzed 765 ENCODE ChIP-seq peak datasets of 207 human TFs with a novel motif discovery pipeline based on recursive, thresholded entropy minimization. This approach, while obviating the need to compensate for skewed nucleotide composition, distinguishes true binding motifs from noise, quantifies the strengths of individual binding sites based on computed affinity and detects adjacent cofactor binding sites that coordinate with the targets of primary, immunoprecipitated TFs. We obtained contiguous and bipartite information theory-based position weight matrices (iPWMs) for 93 sequence-specific TFs, discovered 23 cofactor motifs for 127 TFs and revealed six high-confidence novel motifs. The reliability and accuracy of these iPWMs were determined via four independent validation methods, including the detection of experimentally proven binding sites, explanation of effects of characterized SNPs, comparison with previously published motifs and statistical analyses. We also predict previously unreported TF coregulatory interactions (e.g. TF complexes). These iPWMs constitute a powerful tool for predicting the effects of sequence variants in known binding sites, performing mutation analysis on regulatory SNPs and predicting previously unrecognized binding sites and target genes. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Game Theory Based Security in Wireless Body Area Network with Stackelberg Security Equilibrium.

    Science.gov (United States)

    Somasundaram, M; Sivakumar, R

    2015-01-01

    Wireless Body Area Network (WBAN) is effectively used in healthcare to increase the value of the patient's life and also the value of healthcare services. The biosensor based approach in medical care system makes it difficult to respond to the patients with minimal response time. The medical care unit does not deploy the accessing of ubiquitous broadband connections full time and hence the level of security will not be high always. The security issue also arises in monitoring the user body function records. Most of the systems on the Wireless Body Area Network are not effective in facing the security deployment issues. To access the patient's information with higher security on WBAN, Game Theory with Stackelberg Security Equilibrium (GTSSE) is proposed in this paper. GTSSE mechanism takes all the players into account. The patients are monitored by placing the power position authority initially. The position authority in GTSSE is the organizer and all the other players react to the organizer decision. Based on our proposed approach, experiment has been conducted on factors such as security ratio based on patient's health information, system flexibility level, energy consumption rate, and information loss rate. Stackelberg Security considerably improves the strength of solution with higher security.

  3. Game Theory Based Security in Wireless Body Area Network with Stackelberg Security Equilibrium

    Science.gov (United States)

    Somasundaram, M.; Sivakumar, R.

    2015-01-01

    Wireless Body Area Network (WBAN) is effectively used in healthcare to increase the value of the patient's life and also the value of healthcare services. The biosensor based approach in medical care system makes it difficult to respond to the patients with minimal response time. The medical care unit does not deploy the accessing of ubiquitous broadband connections full time and hence the level of security will not be high always. The security issue also arises in monitoring the user body function records. Most of the systems on the Wireless Body Area Network are not effective in facing the security deployment issues. To access the patient's information with higher security on WBAN, Game Theory with Stackelberg Security Equilibrium (GTSSE) is proposed in this paper. GTSSE mechanism takes all the players into account. The patients are monitored by placing the power position authority initially. The position authority in GTSSE is the organizer and all the other players react to the organizer decision. Based on our proposed approach, experiment has been conducted on factors such as security ratio based on patient's health information, system flexibility level, energy consumption rate, and information loss rate. Stackelberg Security considerably improves the strength of solution with higher security. PMID:26759829

  4. A new approach to sperm preservation based on bioenergetic theory.

    Science.gov (United States)

    Froman, D P; Feltmann, A J

    2010-04-01

    To date, attempts to preserve chicken sperm have been based on a trial-and-error experimental approach. The present work outlines the development of an alternative approach based on empiricism and bioenergetic theory. In previous work, we found fowl sperm motility to be dependent on mitochondrial calcium cycling, phospholipase A(2), and long-chain fatty acids as an endogenous energy source. It is noteworthy that fowl sperm reside within the sperm storage tubules (SST) of the oviduct over an interval of days to weeks after insemination. In this regard, a model for in vivo sperm storage was developed and tested in additional previous research. Sperm penetration of the SST, sperm residence within the SST, and sperm egress from the SST can be explained in terms mitochondrial function. Understanding sperm function and longevity in terms of bioenergetics presented the possibility that sperm could be inactivated by disrupting mitochondrial calcium cycling and could thereby be preserved. However, this possibility also posed a problem: maintenance of the inner membrane potential of the mitochondrion within inactivated sperm. This report describes a series of experiments in which fowl sperm were inactivated by treatment with the calcium chelator tetrasodium 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, and then reactivated by treatment with calcium ions. The effect of tetrasodium 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid on mitochondrial calcium cycling was confirmed by flow cytometry and confocal microscopy. When treated sperm were cooled to 10 degrees C, inactivated sperm could be reactivated throughout a 5-h storage interval. When stored sperm were held for 3 h before reactivation and insemination, fertility was 88% of the control. Storage did not affect hatchability. In summary, short-term storage was realized by manipulating mitochondrial function. We propose that 1) complex V consumes ATP within inactivated sperm and, by doing so, maintains

  5. High strength Ni based composite reinforced by solid solution W(Al) obtained by powder metallurgy

    International Nuclear Information System (INIS)

    Zhao Bo; Zhu Changjun; Ma Xianfeng; Zhao Wei; Tang Huaguo; Cai Shuguang; Qiao Zhuhui

    2007-01-01

    The solid-solution-particle reinforced W(Al)-Ni composites were successfully fabricated by using mechanical alloying (MA) and hot-pressing (HP) technique when the content of Ni is between 45 wt% and 55 wt%. Besides, samples of various original component ratio of Al 50 W 50 to Ni have been fabricated, and the corresponding microcomponents and mechanical properties such as microhardness, ultimate tensile strength and elongation were characterized and discussed. The optimum ultimate tensile strength under the experiment conditions is 1868 MPa with elongation of 10.21% and hardness of 6.62 GPa. X-ray diffraction (XRD), FE-SEM and energy dispersive analysis of X-rays (EDS) were given to analysis the components and morphology of the composite bulk specimens

  6. Strength of "Light" Ferritic and Austenitic Steels Based on the Fe - Mn - Al - C System

    Science.gov (United States)

    Kaputkina, L. M.; Svyazhin, A. G.; Smarygina, I. V.; Kindop, V. E.

    2017-01-01

    The phase composition, the hardness, the mechanical properties at room temperature, and the resistance to hot (950 - 1000°C) and warm (550°C) deformation are studied for cast deformable "light" ferritic and austenitic steels of the Fe - (12 - 25)% Mn - (0 - 15)% Al - (0 - 2)% C system alloyed additionally with about 5% Ni. The high-aluminum high-manganese low-carbon and carbonless ferritic steels at a temperature of about 0.5 T melt have a specific strength close to that of the austenitic steels and may be used as weldable scale-resistant and wear-resistant materials. The high-carbon Fe - (20 - 24)% Mn - (5 - 9)% Al - 5% Ni - 1.5% C austenitic steels may be applied as light high-strength materials operating at cryogenic temperatures after a solution treatment and as scale- and heat-resistant materials in an aged condition.

  7. Bond Strength Mechanism of Fly Ash Based Geopolymer Mortars: A Review

    Science.gov (United States)

    Zailani, W. W. A.; Abdullah, M. M. A. B.; Razak, R. A.; Zainol, M. R. R. M. A.; Tahir, M. F. M.

    2017-11-01

    Geopolymer possess many excellent properties such as high compressive and bond strength, long term durability, better acid resistance and also known as a “Sustainable Material” due to its low carbon emission and low energy consumption. Thus, it is a good opportunity to develop and explore not only for cement and concrete but also as geopolymeric repair materials. This reviews showed that good bonding properties between geopolymeric repair material and concrete substrate is important in order to acquire an enhanced resistance against penetration of harmful substances and avoiding respalling of the repair material by understanding the bonding behaviour. Bond strength depends to the properties of the repair materials itself and also the surface preparations of concrete substrate.

  8. Dynamic strength behavior of a Zr-based bulk metallic glass under shock loading

    International Nuclear Information System (INIS)

    Yu Yu-Ying; Xi Feng; Dai Cheng-Da; Cai Ling-Cang; Tan Ye; Li Xue-Mei; Wu Qiang; Tan Hua

    2015-01-01

    Dynamic strength behavior of Zr 51 Ti 5 Ni 10 Cu 25 Al 9 bulk metallic glass (BMG) up to 66 GPa was investigated in a series of plate impact shock-release and shock-reload experiments. Particle velocity profiles measured at the sample/LiF window interface were used to estimate the shear stress, shear modulus, and yield stress in shocked BMG. Beyond confirming the previously reported strain-softening of shear stress during the shock loading process for BMGs, it is also shown that the softened Zr-BMG still has a high shear modulus and can support large yield stress when released or reloaded from the shocked state, and both the shear modulus and the yield stress appear as strain-hardening behaviors. The work provides a much clearer picture of the strength behavior of BMGs under shock loading, which is useful to comprehensively understand the plastic deformation mechanisms of BMGs. (paper)

  9. Is a school-based physical activity intervention effective for increasing tibial bone strength in boys and girls?

    Science.gov (United States)

    Macdonald, Heather M; Kontulainen, Saija A; Khan, Karim M; McKay, Heather A

    2007-03-01

    This 16-month randomized, controlled school-based study compared change in tibial bone strength between 281 boys and girls participating in a daily program of physical activity (Action Schools! BC) and 129 same-sex controls. The simple, pragmatic intervention increased distal tibia bone strength in prepubertal boys; it had no effect in early pubertal boys or pre or early pubertal girls. Numerous school-based exercise interventions have proven effective for enhancing BMC, but none have used pQCT to evaluate the effects of increased loading on bone strength during growth. Thus, our aim was to determine whether a daily program of physical activity, Action Schools! BC (AS! BC) would improve tibial bone strength in boys and girls who were pre- (Tanner stage 1) or early pubertal (Tanner stage 2 or 3) at baseline. Ten schools were randomized to intervention (INT, 7 schools) or control (CON, 3 schools). The bone-loading component of AS! BC included a daily jumping program (Bounce at the Bell) plus 15 minutes/day of classroom physical activity in addition to regular physical education. We used pQCT to compare 16-month change in bone strength index (BSI, mg2/mm4) at the distal tibia (8% site) and polar strength strain index (SSIp, mm3) at the tibial midshaft (50% site) in 281 boys and girls participating in AS! BC and 129 same-sex controls. We used a linear mixed effects model to analyze our data. Children were 10.2+/-0.6 years at baseline. Intervention boys tended to have a greater increase in BSI (+774.6 mg2/mm4; 95% CI: 672.7, 876.4) than CON boys (+650.9 mg2/mm4; 95% CI: 496.4, 805.4), but the difference was only significant in prepubertal boys (p=0.03 for group x maturity interaction). Intervention boys also tended to have a greater increase in SSIp (+198.6 mm3; 95% CI: 182.9, 214.3) than CON boys (+177.1 mm3; 95% CI: 153.5, 200.7). Change in BSI and SSIp was similar between CON and INT girls. Our findings suggest that a simple, pragmatic program of daily activity

  10. Switching theory-based steganographic system for JPEG images

    Science.gov (United States)

    Cherukuri, Ravindranath C.; Agaian, Sos S.

    2007-04-01

    Cellular communications constitute a significant portion of the global telecommunications market. Therefore, the need for secured communication over a mobile platform has increased exponentially. Steganography is an art of hiding critical data into an innocuous signal, which provide answers to the above needs. The JPEG is one of commonly used format for storing and transmitting images on the web. In addition, the pictures captured using mobile cameras are in mostly in JPEG format. In this article, we introduce a switching theory based steganographic system for JPEG images which is applicable for mobile and computer platforms. The proposed algorithm uses the fact that energy distribution among the quantized AC coefficients varies from block to block and coefficient to coefficient. Existing approaches are effective with a part of these coefficients but when employed over all the coefficients they show there ineffectiveness. Therefore, we propose an approach that works each set of AC coefficients with different frame work thus enhancing the performance of the approach. The proposed system offers a high capacity and embedding efficiency simultaneously withstanding to simple statistical attacks. In addition, the embedded information could be retrieved without prior knowledge of the cover image. Based on simulation results, the proposed method demonstrates an improved embedding capacity over existing algorithms while maintaining a high embedding efficiency and preserving the statistics of the JPEG image after hiding information.

  11. Effect of etching with distinct hydrofluoric acid concentrations on the flexural strength of a lithium disilicate-based glass ceramic.

    Science.gov (United States)

    Prochnow, Catina; Venturini, Andressa B; Grasel, Rafaella; Bottino, Marco C; Valandro, Luiz Felipe

    2017-05-01

    This study examined the effects of distinct hydrofluoric acid concentrations on the mechanical behavior of a lithium disilicate-based glass ceramic. Bar-shaped specimens were produced from ceramic blocks (e.max CAD, Ivoclar Vivadent). The specimens were polished, chamfered, and sonically cleaned in distilled water. The specimens were randomly divided into five groups (n = 23). The HF1, HF3, HF5, and HF10 specimens were etched for 20 s with acid concentrations of 1%, 3%, 5%, and 10%, respectively, while the SC (control) sample was untreated. The etched surfaces were evaluated using a scanning electron microscope and an atomic force microscope. Finally, the roughness was measured, and 3-point bending flexural tests were performed. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey's test (α = 0.05). The Weibull modulus and characteristic strength were also determined. No statistical difference in the roughness and flexural strength was determined among the groups. The structural reliabilities (Weilbull moduli) were similar for the tested groups; however, the characteristic strength of the HF1 specimen was greater than that of the HF10 specimen. Compared with the untreated ceramic, the surface roughness and flexural strength of the ceramic were unaffected upon etching, regardless of the acid concentration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 885-891, 2017. © 2016 Wiley Periodicals, Inc.

  12. Microstructure, characterizations, functionality and compressive strength of cement-based materials using zinc oxide nanoparticles as an additive

    Energy Technology Data Exchange (ETDEWEB)

    Nochaiya, Thanongsak [Department of Physics, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); Sekine, Yoshika [Department of Chemistry, School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Choopun, Supab [Applied Physics Research Laboratory, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Chaipanich, Arnon, E-mail: arnon.chaipanich@cmu.ac.th [Advanced Cement-Based Materials Research Unit, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2015-05-05

    Highlights: • Nano zinc oxide was used as an additive material. • Microstructure and phase characterization of pastes were characterized using SEM and XRD. • TGA and FTIR were also used to determine the hydration reaction. • Compressive strength of ZnO mixes was found to increase at 28 days. - Abstract: Zinc oxide nanoparticles as a nanophotocatalyst has great potential for self-cleaning applications in concrete structures, its effects on the cement hydration, setting time and compressive strength are also important when using it in practice. This paper reports the effects of zinc oxide nanoparticles, as an additive material, on properties of cement-based materials. Setting time, compressive strength and porosity of mortars were investigated. Microstructure and morphology of pastes were characterized using scanning electron microscope and X-ray diffraction (XRD), respectively. Moreover, thermal gravimetric analysis (TGA) and Fourier-transform infrared spectrometer (FTIR) were also used to determine the hydration reaction. The results show that Portland cement paste with additional ZnO was found to slightly increase the water requirement while the setting time presented prolongation period than the control mix. However, compressive strength of ZnO mixes was found to be higher than that of PC mix up to 15% (at 28 days) via filler effect. Microstructure, XRD and TGA results of ZnO pastes show less hydration products before 28 days but similar at 28 days. In addition, FTIR results confirmed the retardation when ZnO was partially added in Portland cement pastes.

  13. Microstructure, characterizations, functionality and compressive strength of cement-based materials using zinc oxide nanoparticles as an additive

    International Nuclear Information System (INIS)

    Nochaiya, Thanongsak; Sekine, Yoshika; Choopun, Supab; Chaipanich, Arnon

    2015-01-01

    Highlights: • Nano zinc oxide was used as an additive material. • Microstructure and phase characterization of pastes were characterized using SEM and XRD. • TGA and FTIR were also used to determine the hydration reaction. • Compressive strength of ZnO mixes was found to increase at 28 days. - Abstract: Zinc oxide nanoparticles as a nanophotocatalyst has great potential for self-cleaning applications in concrete structures, its effects on the cement hydration, setting time and compressive strength are also important when using it in practice. This paper reports the effects of zinc oxide nanoparticles, as an additive material, on properties of cement-based materials. Setting time, compressive strength and porosity of mortars were investigated. Microstructure and morphology of pastes were characterized using scanning electron microscope and X-ray diffraction (XRD), respectively. Moreover, thermal gravimetric analysis (TGA) and Fourier-transform infrared spectrometer (FTIR) were also used to determine the hydration reaction. The results show that Portland cement paste with additional ZnO was found to slightly increase the water requirement while the setting time presented prolongation period than the control mix. However, compressive strength of ZnO mixes was found to be higher than that of PC mix up to 15% (at 28 days) via filler effect. Microstructure, XRD and TGA results of ZnO pastes show less hydration products before 28 days but similar at 28 days. In addition, FTIR results confirmed the retardation when ZnO was partially added in Portland cement pastes

  14. Determination of strength exercise intensities based on the load-power-velocity relationship.

    Science.gov (United States)

    Jandačka, Daniel; Beremlijski, Petr

    2011-06-01

    The velocity of movement and applied load affect the production of mechanical power output and subsequently the extent of the adaptation stimulus in strength exercises. We do not know of any known function describing the relationship of power and velocity and load in the bench press exercise. The objective of the study is to find a function modeling of the relationship of relative velocity, relative load and mechanical power output for the bench press exercise and to determine the intensity zones of the exercise for specifically focused strength training of soccer players. Fifteen highly trained soccer players at the start of a competition period were studied. The subjects of study performed bench presses with the load of 0, 10, 30, 50, 70 and 90% of the predetermined one repetition maximum with maximum possible speed of movement. The mean measured power and velocity for each load (kg) were used to develop a multiple linear regression function which describes the quadratic relationship between the ratio of power (W) to maximum power (W) and the ratios of the load (kg) to one repetition maximum (kg) and the velocity (m•s(-1)) to maximal velocity (m•s(-1)). The quadratic function of two variables that modeled the searched relationship explained 74% of measured values in the acceleration phase and 75% of measured values from the entire extent of the positive power movement in the lift. The optimal load for reaching maximum power output suitable for the dynamics effort strength training was 40% of one repetition maximum, while the optimal mean velocity would be 75% of maximal velocity. Moreover, four zones: maximum power, maximum velocity, velocity-power and strength-power were determined on the basis of the regression function.

  15. Ductile failure analysis of high strength steel in hot forming based on micromechanical damage model

    OpenAIRE

    Ying Liang; Liu Wenquan; Wang Dantong; Hu Ping

    2016-01-01

    The damage evolution of high strength steel at elevated temperature is investigated by using the Gurson-Tvergaard-Needleman (GTN) model. A hybrid method integrated thermal tensile test and numerical technique is employed to identify the damage parameters. The analysis results show that the damage parameters are different at different temperature as the variation of tested material microstructure. Furthermore, the calibrated damage parameters are implemented to simulate a bugling forming at el...

  16. Future directions in psychological assessment: combining evidence-based medicine innovations with psychology's historical strengths to enhance utility.

    Science.gov (United States)

    Youngstrom, Eric A

    2013-01-01

    Assessment has been a historical strength of psychology, with sophisticated traditions of measurement, psychometrics, and theoretical underpinnings. However, training, reimbursement, and utilization of psychological assessment have been eroded in many settings. Evidence-based medicine (EBM) offers a different perspective on evaluation that complements traditional strengths of psychological assessment. EBM ties assessment directly to clinical decision making about the individual, uses simplified Bayesian methods explicitly to integrate assessment data, and solicits patient preferences as part of the decision-making process. Combining the EBM perspective with psychological assessment creates a hybrid approach that is more client centered, and it defines a set of applied research topics that are highly clinically relevant. This article offers a sequence of a dozen facets of the revised assessment process, along with examples of corollary research studies. An eclectic integration of EBM and evidence-based assessment generates a powerful hybrid that is likely to have broad applicability within clinical psychology and enhance the utility of psychological assessments.

  17. Experimental Investigation of the Peak Shear Strength Criterion Based on Three-Dimensional Surface Description

    Science.gov (United States)

    Liu, Quansheng; Tian, Yongchao; Ji, Peiqi; Ma, Hao

    2018-04-01

    The three-dimensional (3D) morphology of joints is enormously important for the shear mechanical properties of rock. In this study, three-dimensional morphology scanning tests and direct shear tests are conducted to establish a new peak shear strength criterion. The test results show that (1) surface morphology and normal stress exert significant effects on peak shear strength and distribution of the damage area. (2) The damage area is located at the steepest zone facing the shear direction; as the normal stress increases, it extends from the steepest zone toward a less steep zone. Via mechanical analysis, a new formula for the apparent dip angle is developed. The influence of the apparent dip angle and the average joint height on the potential contact area is discussed, respectively. A new peak shear strength criterion, mainly applicable to specimens under compression, is established by using new roughness parameters and taking the effects of normal stress and the rock mechanical properties into account. A comparison of this newly established model with the JRC-JCS model and the Grasselli's model shows that the new one could apparently improve the fitting effect. Compared with earlier models, the new model is simpler and more precise. All the parameters in the new model have clear physical meanings and can be directly determined from the scanned data. In addition, the indexes used in the new model are more rational.

  18. Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C.S., E-mail: cst311@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kashyap, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kim, D.H. [Center for Non-Crystalline Materials, Department of Metallurgical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2015-07-15

    Developments of aluminum alloys that can retain strength at and above 250 °C present a significant challenge. In this paper we report an ultrafine scale Al–Fe–Ni eutectic alloy with less than 3.5 at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6–8%. The yield stress under compression at 300 °C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al–Al{sub 3}Ni rod eutectic with spacing of ~90 nm enveloped by a lamellar eutectic of Al–Al{sub 9}FeNi (~140 nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al–Al{sub 3}Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al{sub 3}Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

  19. Flexural strength and modulus of elasticity of different types of resin-based composites.

    Science.gov (United States)

    Rodrigues Junior, Sinval Adalberto; Zanchi, Cesar Henrique; Carvalho, Rodrigo Varella de; Demarco, Flávio Fernando

    2007-01-01

    The aim of the study was to test whether the filler composition of resin composites influences their flexural strength and modulus of elasticity. Flexural strength and modulus of elasticity were obtained through a three-point bending test. Twelve bar shaped specimens of 5 commercially available composites--Supreme (3M/ESPE), a universal nanofilled composite; Esthet-X (Dentsply), Z-250 (3M/ESPE), Charisma (Heraeus Kulzer), universal hybrid composites; and Helio Fill (Vigodent), a microfine composite--were confectioned according to the ISO 4049/2000 specifications. The test was performed after a 7-days storage time using a universal test machine with a crosshead speed of 1 mm/min. The filler weight content was determined by the ashing technique. The data obtained on the mechanical properties were submitted to ANOVA and Tukey test (p elasticity results were observed among the universal hybrid composites. The nanofilled composite presented intermediary results. Within the limitations of this in vitro study, it could be concluded that the filler content significantly interfered in the flexural strength and modulus of elasticity of the composites tested.

  20. Effects of framework design and layering material on fracture strength of implant-supported zirconia-based molar crowns.

    Science.gov (United States)

    Kamio, Shingo; Komine, Futoshi; Taguchi, Kohei; Iwasaki, Taro; Blatz, Markus B; Matsumura, Hideo

    2015-12-01

    To evaluate the effects of framework design and layering material on the fracture strength of implant-supported zirconia-based molar crowns. Sixty-six titanium abutments (GingiHue Post) were tightened onto dental implants (Implant Lab Analog). These abutment-implant complexes were randomly divided into three groups (n = 22) according to the design of the zirconia framework (Katana), namely, uniform-thickness (UNI), anatomic (ANA), and supported anatomic (SUP) designs. The specimens in each design group were further divided into two subgroups (n = 11): zirconia-based all-ceramic restorations (ZAC group) and zirconia-based restorations with an indirect composite material (Estenia C&B) layered onto the zirconia framework (ZIC group). All crowns were cemented on implant abutments, after which the specimens were tested for fracture resistance. The data were analyzed with the Kruskal-Wallis test and the Mann-Whitney U-test with the Bonferroni correction (α = 0.05). The following mean fracture strength values (kN) were obtained in UNI design, ANA design, and SUP design, respectively: Group ZAC, 3.78, 6.01, 6.50 and Group ZIC, 3.15, 5.65, 5.83. In both the ZAC and ZIC groups, fracture strength was significantly lower for the UNI design than the other two framework designs (P = 0.001). Fracture strength did not significantly differ (P > 0.420) between identical framework designs in the ZAC and ZIC groups. A framework design with standardized layer thickness and adequate support of veneer by zirconia frameworks, as in the ANA and SUP designs, increases fracture resistance in implant-supported zirconia-based restorations under conditions of chewing attrition. Indirect composite material and porcelain perform similarly as layering materials on zirconia frameworks. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. On the Relation of Setting and Early-Age Strength Development to Porosity and Hydration in Cement-Based Materials

    OpenAIRE

    Lootens, Didier; Bentz, Dale P.

    2016-01-01

    Previous research has demonstrated a linear relationship between compressive strength (mortar cubes and concrete cylinders) and cumulative heat release normalized per unit volume of (mixing) water for a wide variety of cement-based mixtures at ages of 1 d and beyond. This paper utilizes concurrent ultrasonic reflection and calorimetry measurements to further explore this relationship from the time of specimen casting to 3 d. The ultrasonic measurements permit a continuous evaluation of thicke...

  2. Machine-Learning-Based Future Received Signal Strength Prediction Using Depth Images for mmWave Communications

    OpenAIRE

    Okamoto, Hironao; Nishio, Takayuki; Nakashima, Kota; Koda, Yusuke; Yamamoto, Koji; Morikura, Masahiro; Asai, Yusuke; Miyatake, Ryo

    2018-01-01

    This paper discusses a machine-learning (ML)-based future received signal strength (RSS) prediction scheme using depth camera images for millimeter-wave (mmWave) networks. The scheme provides the future RSS prediction of any mmWave links within the camera's view, including links where nodes are not transmitting frames. This enables network controllers to conduct network operations before line-of-sight path blockages degrade the RSS. Using the ML techniques, the prediction scheme automatically...

  3. TO THE SOLUTION OF PROBLEMS ABOUT THE RAILWAYS CALCULATION FOR STRENGTH TAKING INTO ACCOUNT UNEQUAL ELASTICITY OF THE SUBRAIL BASE

    Directory of Open Access Journals (Sweden)

    D. M. Kurhan

    2014-11-01

    Full Text Available Purpose. The module of elasticity of the subrail base is one of the main characteristics for an assessment intense the deformed condition of a track. Need for different cases to consider unequal elasticity of the subrail base repeatedly was considered, however, results contained rather difficult mathematical approaches and the obtained decisions didn't keep within borders of standard engineering calculation of a railway on strength. Therefore the purpose of this work is obtaining the decision within this document. Methodology. It is offered to consider a rail model as a beam which has the distributed loading of such outline corresponding to value of the module of elasticity that gives an equivalent deflection at free seating on bearing parts. Findings. The method of the accounting of gradual change of the module of elasticity of the subrail base by means of the correcting coefficient in engineering calculation of a way on strength was received. Expansion of existing calculation of railways strength was developed for the accounting of sharp change of the module of elasticity of the subrail base (for example, upon transition from a ballast design of a way on the bridge. The characteristic of change of forces operating from a rail on a basis, depending on distance to the bridge on an approach site from a ballast design of a way was received. The results of the redistribution of forces after a sudden change in the elastic modulus of the base under the rail explain the formation of vertical irregularities before the bridge. Originality. The technique of engineering calculation of railways strength for performance of calculations taking into account unequal elasticity of the subrail base was improved. Practical value. The obtained results allow carrying out engineering calculations for an assessment of strength of a railway in places of unequal elasticity caused by a condition of a way or features of a design. The solution of the return task on

  4. MaxEnt-Based Ecological Theory: A Template for Integrated Catchment Theory

    Science.gov (United States)

    Harte, J.

    2017-12-01

    The maximum information entropy procedure (MaxEnt) is both a powerful tool for inferring least-biased probability distributions from limited data and a framework for the construction of complex systems theory. The maximum entropy theory of ecology (METE) describes remarkably well widely observed patterns in the distribution, abundance and energetics of individuals and taxa in relatively static ecosystems. An extension to ecosystems undergoing change in response to disturbance or natural succession (DynaMETE) is in progress. I describe the structure of both the static and the dynamic theory and show a range of comparisons with census data. I then propose a generalization of the MaxEnt approach that could provide a framework for a predictive theory of both static and dynamic, fully-coupled, eco-socio-hydrological catchment systems.

  5. The Influence of No-Primer Adhesives and Anchor Pylons Bracket Bases on Shear Bond Strength of Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Andrea Scribante

    2013-01-01

    Full Text Available Objective. The aim of this study was to compare the shear bond strength (SBS and adhesive remnant index (ARI scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP with different bracket bases (anchor pylons and 80-gauge mesh were bonded to the teeth using a conventional adhesive (Transbond XT and two different no-primer adhesive (Ortho Cem; Heliosit systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs, Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs.

  6. IMMAN: free software for information theory-based chemometric analysis.

    Science.gov (United States)

    Urias, Ricardo W Pino; Barigye, Stephen J; Marrero-Ponce, Yovani; García-Jacas, César R; Valdes-Martiní, José R; Perez-Gimenez, Facundo

    2015-05-01

    The features and theoretical background of a new and free computational program for chemometric analysis denominated IMMAN (acronym for Information theory-based CheMoMetrics ANalysis) are presented. This is multi-platform software developed in the Java programming language, designed with a remarkably user-friendly graphical interface for the computation of a collection of information-theoretic functions adapted for rank-based unsupervised and supervised feature selection tasks. A total of 20 feature selection parameters are presented, with the unsupervised and supervised frameworks represented by 10 approaches in each case. Several information-theoretic parameters traditionally used as molecular descriptors (MDs) are adapted for use as unsupervised rank-based feature selection methods. On the other hand, a generalization scheme for the previously defined differential Shannon's entropy is discussed, as well as the introduction of Jeffreys information measure for supervised feature selection. Moreover, well-known information-theoretic feature selection parameters, such as information gain, gain ratio, and symmetrical uncertainty are incorporated to the IMMAN software ( http://mobiosd-hub.com/imman-soft/ ), following an equal-interval discretization approach. IMMAN offers data pre-processing functionalities, such as missing values processing, dataset partitioning, and browsing. Moreover, single parameter or ensemble (multi-criteria) ranking options are provided. Consequently, this software is suitable for tasks like dimensionality reduction, feature ranking, as well as comparative diversity analysis of data matrices. Simple examples of applications performed with this program are presented. A comparative study between IMMAN and WEKA feature selection tools using the Arcene dataset was performed, demonstrating similar behavior. In addition, it is revealed that the use of IMMAN unsupervised feature selection methods improves the performance of both IMMAN and WEKA

  7. Predicting Folding Sequences Based on the Maximum Rock Strength and Mechanical Equilibrium

    Science.gov (United States)

    Cubas, N.; Souloumiac, P.; Maillot, B.; Leroy, Y. M.

    2007-12-01

    The objective is to propose and validate simple procedures, compared to the finite-element method, to select and optimize the dominant mode of folding in fold-and-thrust belts and accretionary wedges, and to determine its stress distribution. Mechanical equilibrium as well as the constraints due to the limited rock strength of the bulk material and of major discontinuities, such as décollements, are accounted for. The first part of the proposed procedure, which is at the core of the external approach of classical limit analysis, consists in estimating the least upper bound on the tectonic force by minimisation of the internal dissipation and part of the external work. The new twist to the method is that the optimization is also done with respect to the geometry of the evolving fold. If several folding events are possible, the dominant mode is the one leading to the least upper bound. The second part of the procedure is based on the Equilibrium Element Method, which is an application of the internal approach of limit analysis. The optimum stress field, obtained by spatial discretisation of the fold, provides the best lower bound on the tectonic force. The difference between the two bounds defines an error estimate of the exact unknown tectonic force. To show the merits of the proposed procedure, its first part is applied to predict the life span of a thrust within an accretionary prism, from its onset, its development with a relief build up and its arrest because of the onset of a more favorable new thrust (Cubas et al., 2007). This life span is sensitive to the friction angles over the ramp and the décollement. It is shown how the normal sequence of thrusting in a supercritical wedge is ended with the first out-of sequence event. The second part of the procedure provides the stress state over each thrust showing that the active back thrust is a narrow fan which dip is sensitive to the friction angle over the ramp and the amount of relief build up (Souloumiac et

  8. Empirical source strength correlations for rans-based acoustic analogy methods

    Science.gov (United States)

    Kube-McDowell, Matthew Tyndall

    JeNo is a jet noise prediction code based on an acoustic analogy method developed by Mani, Gliebe, Balsa, and Khavaran. Using the flow predictions from a standard Reynolds-averaged Navier-Stokes computational fluid dynamics solver, JeNo predicts the overall sound pressure level and angular spectra for high-speed hot jets over a range of observer angles, with a processing time suitable for rapid design purposes. JeNo models the noise from hot jets as a combination of two types of noise sources; quadrupole sources dependent on velocity fluctuations, which represent the major noise of turbulent mixing, and dipole sources dependent on enthalpy fluctuations, which represent the effects of thermal variation. These two sources are modeled by JeNo as propagating independently into the far-field, with no cross-correlation at the observer location. However, high-fidelity computational fluid dynamics solutions demonstrate that this assumption is false. In this thesis, the theory, assumptions, and limitations of the JeNo code are briefly discussed, and a modification to the acoustic analogy method is proposed in which the cross-correlation of the two primary noise sources is allowed to vary with the speed of the jet and the observer location. As a proof-of-concept implementation, an empirical correlation correction function is derived from comparisons between JeNo's noise predictions and a set of experimental measurements taken for the Air Force Aero-Propulsion Laboratory. The empirical correlation correction is then applied to JeNo's predictions of a separate data set of hot jets tested at NASA's Glenn Research Center. Metrics are derived to measure the qualitative and quantitative performance of JeNo's acoustic predictions, and the empirical correction is shown to provide a quantitative improvement in the noise prediction at low observer angles with no freestream flow, and a qualitative improvement in the presence of freestream flow. However, the results also demonstrate

  9. Viscosity Prediction of Hydrocarbon Mixtures Based on the Friction Theory

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Cisneros, Sergio; Stenby, Erling Halfdan

    2001-01-01

    The application and capability of the friction theory (f-theory) for viscosity predictions of hydrocarbon fluids is further illustrated by predicting the viscosity of binary and ternary liquid mixtures composed of n-alkanes ranging from n-pentane to n-decane for wide ranges of temperature and from...

  10. Screen-based sedentary behavior and associations with functional strength in 6-15 year-old children in the United States.

    Science.gov (United States)

    Edelson, Lisa R; Mathias, Kevin C; Fulgoni, Victor L; Karagounis, Leonidas G

    2016-02-04

    Physical strength is associated with improved health outcomes in children. Heavier children tend to have lower functional strength and mobility. Physical activity can increase children's strength, but it is unknown how different types of electronic media use impact physical strength. Data from the NHANES National Youth Fitness Survey (NNYFS) from children ages 6-15 were analyzed in this study. Regression models were conducted to determine if screen-based sedentary behaviors (television viewing time, computer/video game time) were associated with strength measures (grip, leg extensions, modified pull-ups, plank) while controlling for potential confounders including child age, sex, BMI z-score, and days per week with 60+ minutes of physical activity. Grip strength and leg extensions divided by body weight were analyzed to provide measures of relative strength together with pull-ups and plank, which require lifting the body. The results from the regression models showed the hypothesized inverse association between TV time and all strength measures. Computer time was only significantly inversely associated with the ability to do one or more pull-ups. This study shows that television viewing, but not computer/videogames, is inversely associated with measures of child strength while controlling for child characteristics and physical activity. These findings suggest that "screen time" may not be a unified construct with respect to strength outcomes and that further exploration of the potential benefits of reducing television time on children's strength and related mobility is needed.

  11. Towards evidence based strength training: a comparison of muscle forces during deadlifts, goodmornings and split squats.

    Science.gov (United States)

    Schellenberg, Florian; Taylor, William R; Lorenzetti, Silvio

    2017-01-01

    To ensure an efficient and targeted adaptation with low injury risk during strength exercises, knowledge of the participant specific internal loading conditions is essential. The goal of this study was to calculate the lower limb muscles forces during the strength exercises deadlifts, goodmornings and splits squats by means of musculoskeletal simulation. 11 participants were assessed performing 10 different variations of split squats by varying the step length as well as the maximal frontal tibia angle, and 13 participants were measured performing deadlift and goodmorning exercises. Using individualised musculoskeletal models, forces of the Quadriceps ( four parts), Hamstrings (four parts) and m. gluteus maximus (three parts) were computed. Deadlifts resulted highest loading for the Quadriceps, especially for the vasti (18-34 N/kg), but not for the rectus femoris (8-10 N/kg), which exhibited its greatest loading during split squats (13-27 N/kg) in the rear limb. Hamstrings were loaded isometrically during goodmornings but dynamically during deadlifts. For the m. gluteus maximus , the highest loading was observed during split squats in the front limb (up to 25 N/kg), while deadlifts produced increasingly, large loading over large ranges of motion in hip and knee. Acting muscle forces vary between exercises, execution form and joint angle. For all examined muscles, deadlifts produced considerable loading over large ranges of motion, while split squats seem to be highly dependent upon exercise variation. This study provides key information to design strength-training programs with respect to loading conditions and ranges of motion of lower extremity muscles.

  12. Influence of increment thickness on dentin bond strength and light transmission of composite base materials.

    Science.gov (United States)

    Omran, Tarek A; Garoushi, Sufyan; Abdulmajeed, Aous A; Lassila, Lippo V; Vallittu, Pekka K

    2017-06-01

    Bulk-fill resin composites (BFCs) are gaining popularity in restorative dentistry due to the reduced chair time and ease of application. This study aimed to evaluate the influence of increment thickness on dentin bond strength and light transmission of different BFCs and a new discontinuous fiber-reinforced composite. One hundred eighty extracted sound human molars were prepared for a shear bond strength (SBS) test. The teeth were divided into four groups (n = 45) according to the resin composite used: regular particulate filler resin composite: (1) G-ænial Anterior [GA] (control); bulk-fill resin composites: (2) Tetric EvoCeram Bulk Fill [TEBF] and (3) SDR; and discontinuous fiber-reinforced composite: (4) everX Posterior [EXP]. Each group was subdivided according to increment thickness (2, 4, and 6 mm). The irradiance power through the material of all groups/subgroups was quantified (MARC® Resin Calibrator; BlueLight Analytics Inc.). Data were analyzed using two-way ANOVA followed by Tukey's post hoc test. SBS and light irradiance decreased as the increment's height increased (p composite used. EXP presented the highest SBS in 2- and 4-mm-thick increments when compared to other composites, although the differences were not statistically significant (p > 0.05). Light irradiance mean values arranged in descending order were (p composites. Discontinuous fiber-reinforced composite showed the highest value of curing light transmission, which was also seen in improved bonding strength to the underlying dentin surface. Discontinuous fiber-reinforced composite can be applied safely in bulks of 4-mm increments same as other bulk-fill composites, although, in 2-mm thickness, the investigated composites showed better performance.

  13. Complete theory of symmetry-based indicators of band topology.

    Science.gov (United States)

    Po, Hoi Chun; Vishwanath, Ashvin; Watanabe, Haruki

    2017-06-30

    The interplay between symmetry and topology leads to a rich variety of electronic topological phases, protecting states such as the topological insulators and Dirac semimetals. Previous results, like the Fu-Kane parity criterion for inversion-symmetric topological insulators, demonstrate that symmetry labels can sometimes unambiguously indicate underlying band topology. Here we develop a systematic approach to expose all such symmetry-based indicators of band topology in all the 230 space groups. This is achieved by first developing an efficient way to represent band structures in terms of elementary basis states, and then isolating the topological ones by removing the subset of atomic insulators, defined by the existence of localized symmetric Wannier functions. Aside from encompassing all earlier results on such indicators, including in particular the notion of filling-enforced quantum band insulators, our theory identifies symmetry settings with previously hidden forms of band topology, and can be applied to the search for topological materials.Understanding the role of topology in determining electronic structure can lead to the discovery, or appreciation, of materials with exotic properties such as protected surface states. Here, the authors present a framework for identifying topologically distinct band-structures for all 3D space groups.

  14. Cognitive performance modeling based on general systems performance theory.

    Science.gov (United States)

    Kondraske, George V

    2010-01-01

    General Systems Performance Theory (GSPT) was initially motivated by problems associated with quantifying different aspects of human performance. It has proved to be invaluable for measurement development and understanding quantitative relationships between human subsystem capacities and performance in complex tasks. It is now desired to bring focus to the application of GSPT to modeling of cognitive system performance. Previous studies involving two complex tasks (i.e., driving and performing laparoscopic surgery) and incorporating measures that are clearly related to cognitive performance (information processing speed and short-term memory capacity) were revisited. A GSPT-derived method of task analysis and performance prediction termed Nonlinear Causal Resource Analysis (NCRA) was employed to determine the demand on basic cognitive performance resources required to support different levels of complex task performance. This approach is presented as a means to determine a cognitive workload profile and the subsequent computation of a single number measure of cognitive workload (CW). Computation of CW may be a viable alternative to measuring it. Various possible "more basic" performance resources that contribute to cognitive system performance are discussed. It is concluded from this preliminary exploration that a GSPT-based approach can contribute to defining cognitive performance models that are useful for both individual subjects and specific groups (e.g., military pilots).

  15. Statistical lamb wave localization based on extreme value theory

    Science.gov (United States)

    Harley, Joel B.

    2018-04-01

    Guided wave localization methods based on delay-and-sum imaging, matched field processing, and other techniques have been designed and researched to create images that locate and describe structural damage. The maximum value of these images typically represent an estimated damage location. Yet, it is often unclear if this maximum value, or any other value in the image, is a statistically significant indicator of damage. Furthermore, there are currently few, if any, approaches to assess the statistical significance of guided wave localization images. As a result, we present statistical delay-and-sum and statistical matched field processing localization methods to create statistically significant images of damage. Our framework uses constant rate of false alarm statistics and extreme value theory to detect damage with little prior information. We demonstrate our methods with in situ guided wave data from an aluminum plate to detect two 0.75 cm diameter holes. Our results show an expected improvement in statistical significance as the number of sensors increase. With seventeen sensors, both methods successfully detect damage with statistical significance.

  16. STUDENTS’ GEOMETRIC THINKING BASED ON VAN HIELE’S THEORY

    Directory of Open Access Journals (Sweden)

    Harina Fitriyani

    2018-02-01

    Full Text Available The current study aims to identify the development level of students’ geometric thinking in mathematics education department, Universitas Ahmad Dahlan based on van Hiele’s theory. This is a descriptive qualitative research with the respondents as many as 129 students. In addition to researchers, the instrument used in this study is a test consisting of 25 items multiple choice questions. The data is analyzed by using Milles and Huberman model. The result shows that there were 30,65% of students in pre-visualization level, 21,51% of students in visualizes level, and 29,03% of students in analyze level, 16,67% of students in informal deduction level, 2,15% of students in deduction level, and 0,00% of student in rigor level. Furthermore, findings indicated a transition level among development levels of geometric thinking in pre-analyze, pre-informal deduction, pre-deduction, and pre-rigor that were 20%; 13,44%; 6,45%; 1,08% respectively. The other findings were 40,32% of students were difficult to determine and 4,3% of students cannot be identified.

  17. Feature extraction algorithm for space targets based on fractal theory

    Science.gov (United States)

    Tian, Balin; Yuan, Jianping; Yue, Xiaokui; Ning, Xin

    2007-11-01

    In order to offer a potential for extending the life of satellites and reducing the launch and operating costs, satellite servicing including conducting repairs, upgrading and refueling spacecraft on-orbit become much more frequently. Future space operations can be more economically and reliably executed using machine vision systems, which can meet real time and tracking reliability requirements for image tracking of space surveillance system. Machine vision was applied to the research of relative pose for spacecrafts, the feature extraction algorithm was the basis of relative pose. In this paper fractal geometry based edge extraction algorithm which can be used in determining and tracking the relative pose of an observed satellite during proximity operations in machine vision system was presented. The method gets the gray-level image distributed by fractal dimension used the Differential Box-Counting (DBC) approach of the fractal theory to restrain the noise. After this, we detect the consecutive edge using Mathematical Morphology. The validity of the proposed method is examined by processing and analyzing images of space targets. The edge extraction method not only extracts the outline of the target, but also keeps the inner details. Meanwhile, edge extraction is only processed in moving area to reduce computation greatly. Simulation results compared edge detection using the method which presented by us with other detection methods. The results indicate that the presented algorithm is a valid method to solve the problems of relative pose for spacecrafts.

  18. System of marketing deciding support based on game theory

    Directory of Open Access Journals (Sweden)

    Gordana Dukić

    2008-12-01

    Full Text Available Quantitative methods and models can be applied in numerous spheres of marketing deciding. The choice of optimal strategy in product advertising is one of the problems that the marketing-management often meets. The use of models developed within the framework of game theory makes significantly easier to find out the solutions of conflict situations that appear herewith. The system of deciding support presented in this work is based on the supposition that two opposed sides take part in the game. With the aim of deciding process promotion, the starting model incorporates computer simulation of percentile changes in the market share that represent elements of payment matrix. The supposition is that the random variables that represent them follow the normal division. It is necessary to carry out the evaluation of their parameters because of relevant data. Information techniques, computer and the adequate program applications take the special position in solving and analysis of the suggested model. This kind of their application represents the basic characteristic of the deciding support system.

  19. Modeling Sensor Reliability in Fault Diagnosis Based on Evidence Theory

    Directory of Open Access Journals (Sweden)

    Kaijuan Yuan

    2016-01-01

    Full Text Available Sensor data fusion plays an important role in fault diagnosis. Dempster–Shafer (D-R evidence theory is widely used in fault diagnosis, since it is efficient to combine evidence from different sensors. However, under the situation where the evidence highly conflicts, it may obtain a counterintuitive result. To address the issue, a new method is proposed in this paper. Not only the statistic sensor reliability, but also the dynamic sensor reliability are taken into consideration. The evidence distance function and the belief entropy are combined to obtain the dynamic reliability of each sensor report. A weighted averaging method is adopted to modify the conflict evidence by assigning different weights to evidence according to sensor reliability. The proposed method has better performance in conflict management and fault diagnosis due to the fact that the information volume of each sensor report is taken into consideration. An application in fault diagnosis based on sensor fusion is illustrated to show the efficiency of the proposed method. The results show that the proposed method improves the accuracy of fault diagnosis from 81.19% to 89.48% compared to the existing methods.

  20. Yield strength prediction in Ni-base alloy 718Plus based on thermo-kinetic precipitation simulation

    International Nuclear Information System (INIS)

    Ahmadi, M.R.; Povoden-Karadeniz, E.; Whitmore, L.; Stockinger, M.; Falahati, A.; Kozeschnik, E.

    2014-01-01

    The yield strength of Allvac ® 718Plus ™ during aging is computed using integrated physical models that take into account intrinsic, grain boundary, solid solution and precipitate strengthening contributions. Precipitation strengthening of γ′ has the main effect on the final yield strength in this alloy during aging, with the coherency and anti-phase boundary effects providing the major strengthening contributions. We utilize transmission electron microscopy to obtain the unknown physical parameters entering the strengthening models and compare precipitate size and distribution with the simulation results

  1. Nonlinear Fatigue Damage Model Based on the Residual Strength Degradation Law

    Science.gov (United States)

    Yongyi, Gao; Zhixiao, Su

    In this paper, a logarithmic expression to describe the residual strength degradation process is developed in order to fatigue test results for normalized carbon steel. The definition and expression of fatigue damage due to symmetrical stress with a constant amplitude are also given. The expression of fatigue damage can also explain the nonlinear properties of fatigue damage. Furthermore, the fatigue damage of structures under random stress is analyzed, and an iterative formula to describe the fatigue damage process is deduced. Finally, an approximate method for evaluating the fatigue life of structures under repeated random stress blocking is presented through various calculation examples.

  2. Ductile failure analysis of high strength steel in hot forming based on micromechanical damage model

    Directory of Open Access Journals (Sweden)

    Ying Liang

    2016-01-01

    Full Text Available The damage evolution of high strength steel at elevated temperature is investigated by using the Gurson-Tvergaard-Needleman (GTN model. A hybrid method integrated thermal tensile test and numerical technique is employed to identify the damage parameters. The analysis results show that the damage parameters are different at different temperature as the variation of tested material microstructure. Furthermore, the calibrated damage parameters are implemented to simulate a bugling forming at elevated temperature. The experimental results show the availability of GTN damage model in analyzing sheet formability in hot forming.

  3. Rutting Prediction in Asphalt Pavement Based on Viscoelastic Theory

    Directory of Open Access Journals (Sweden)

    Nahi Mohammed Hadi

    2016-01-01

    Full Text Available Rutting is one of the most disturbing failures on the asphalt roads due to the interrupting it is caused to the drivers. Predicting of asphalt pavement rutting is essential tool leads to better asphalt mixture design. This work describes a method of predicting the behaviour of various asphalt pavement mixes and linking these to an accelerated performance testing. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating the laboratory testing of asphalt mixes in Hamburg Wheel Rut Tester (HWRT for rutting. The creep parameters C1, C2 and C3 are developed from the triaxial repeated load creep test at 50°C and at a frequency of 1 Hz and the modulus of elasticity and Poisson’ s ratio determined at the same temperature. Viscoelastic model (creep model is adopted using a FE simulator (ANSYS in order to calculate the rutting for various mixes under a uniform loading pressure of 500 kPa. An eight-node with a three Degrees of Freedom (UX, UY, and UZ Element is used for the simulation. The creep model developed for HWRT tester was verified by comparing the predicted rut depths with the measured one and by comparing the rut depth with ABAQUS result from literature. Reasonable agreement can be obtained between the predicted rut depths and the measured one. Moreover, it is found that creep model parameter C1 and C3 have a strong relationship with rutting. It was clear that the parameter C1 strongly influences rutting than the parameter C3. Finally, it can be concluded that creep model based on finite element method can be used as an effective tool to analyse rutting of asphalt pavements.

  4. The Development of an Attribution-Based Theory of Motivation: A History of Ideas

    Science.gov (United States)

    Weiner, Bernard

    2010-01-01

    The history of ideas guiding the development of an attribution-based theory of motivation is presented. These influences include the search for a "grand" theory of motivation (from drive and expectancy/value theory), an attempt to represent how the past may influence the present and the future (as Thorndike accomplished), and the…

  5. Theory-Based Evaluation Meets Ambiguity: The Role of Janus Variables

    Science.gov (United States)

    Dahler-Larsen, Peter

    2018-01-01

    As theory-based evaluation (TBE) engages in situations where multiple stakeholders help develop complex program theory about dynamic phenomena in politically contested settings, it becomes difficult to develop and use program theory without ambiguity. The purpose of this article is to explore ambiguity as a fruitful perspective that helps TBE face…

  6. Evaluating the shear bond strength of enamel and dentin with or without etching: A comparative study between dimethacrylate-based and silorane-based adhesives

    Science.gov (United States)

    Hajizadeh, Hila; Nasseh, Atefeh; Rahmanpour, Naim

    2015-01-01

    Background Silorane-based composites and their specific self-etch adhesive were introduced to conquest the polymerization shrinkage of methacrylate-based composites. It has been shown that additional etching of enamel and dentin can improve the bond strength of self-etch methacrylate-based adhesives but this claim is not apparent about silorane-based adhesives. Our objective was to compare the shear bond strength (SBS) of enamel and dentin between silorane-based adhesive resin and a methacrylate-based resin with or without additional etching. Material and Methods 40 sound human premolars were prepared and divided into two groups: 1- Filtek P60 composite and Clearfil SE Bond adhesive; 2- Filtek P90 composite and Silorane adhesive. Each group divided into two subgroups: with or without additional etching. For additional etching, 37% acid phosphoric was applied before bonding procedure. A cylinder of the composite was bonded to the surface. After 24 hours storage and 500 thermo cycling between 5-55°C, shear bond strength was assessed with the cross head speed of 0.5 mm/min. Then, bonded surfaces were observed under stereomicroscope to determine the failure mode. Data were analyzed with two-way ANOVA and Fischer exact test. Results Shear bond strength of Filtek P60 composite was significantly higher than Filtek P90 composite both in enamel and dentin surfaces (Penamel or dentin for each of the composites (P>0.05). There was no interaction between composite type and additional etching (P>0.05). Failure pattern was mainly adhesive and no significant correlation was found between failure and composite type or additional etching (P>0.05). Conclusions Shear bond strength of methacrylate-based composite was significantly higher than silorane-based composite both in enamel and dentin surfaces and additional etching had no significant effect on shear bond strength in enamel or dentin for each of the composites. The mode of failure had no meaningful relation to the type of

  7. Analysis of the physical properties of trehalose-water-lithium iodide based on the bond strength coordination number fluctuation model

    International Nuclear Information System (INIS)

    Sahara; Jean L Ndeugueu; Masaru Aniya

    2010-01-01

    The temperature dependence of the viscosity of trehalose-water-lithium iodide system has been investigated by the mean of the Bond Strength Coordination Number Fluctuation (BSCNF) model. The result indicates that by increasing the trehalose content, maintaining the content of LiI constant, the fragility decreases due to the increase of the connectivity between the structural units. Our analysis suggests also that the fragility of the system is controlled by the amount of water in the composition. By increasing the water content, the total bond strength decreases and its fluctuation increases, resulting in the increase of the fragility. Based on the analysis of the obtained parameters of the BSCNF model, a physical interpretation of the VFT parameters reported in a previous study has been given. (author)

  8. THE BIODEGRADABILITY AND MECHANICAL STRENGTH OF NUTRITIVE POTS FOR VEGETABLE PLANTING BASED ON LIGNOCELLULOSE COMPOSITE MATERIALS

    Directory of Open Access Journals (Sweden)

    Petronela Nechita

    2010-04-01

    Full Text Available Considering the mild degradation strength and the fact that it may be an organic matter reserve for the soil, in the past years lignocellulosic materials have been used as fibrous raw materials in the manufacture of biodegradable nutritive pots for the seedling in vegetable containerized production. This paper analyses the behavior of the nutritive pots made from biodegradable composites for the vegetable seedling production process, focusing on their mechanical strength properties and biodegradability. It was found that the biodegradability of composite materials obtained from a mixture of secondary cellulosic fibers, peat, and additives, is strongly influenced by the presence or absence of the rhizosphere effect and the synergistic relations set in the culture substrate between the plant roots and microorganisms, which develop permanently the recycling and solubilization of mineral nutrients. The results showed that the presence in the substrate of some complex populations made by heterotrophic bacteria favors full degradation of the pulp and lignin contained in the substrate and pots composition. Therefore, unlike the reference sample (plant-free, cultivated versions exhibited an intense biodegradation on the account of rhizosphere effect.

  9. The tensile strength test of thermoplastic materials based on poly(butylene terephtalate

    Directory of Open Access Journals (Sweden)

    Rzepecka Anna

    2017-01-01

    Full Text Available Thermoplastic composites go toward making an increasingly greater percentage of all manufacturing polymer composites. They have a lot of beneficial properties and their manufacturing using injecting and extrusion methods is a very easy and cheap process. Their properties significantly overtake the properties of traditional materials and it is the reason for their use. Scientists are continuously carrying out research to find new applications of composites materials in new industries, not only in the automotive or aircraft industry. When thermoplastic composites are manufactured a very important factor is the appropriate accommodation of tensile strength to their predestination. Scientists need to know the behaviour of these materials during the impact of different forces, and the factors of working in normal conditions too. The main aim of this article was macroscopic and microscopic analysis of the structure of thermoplastic composites after static tensile strength test. Materials which were analysed were thermoplastic materials which have poly(butylene terephthalate – PBT matrix reinforced with different content glass fibres – from 10% for 30%. In addition, research showed the necessary force to receive fracture and set their distinguishing characteristic down.

  10. Entrepreneurship education: A strength-based approach to substance use and suicide prevention for American Indian adolescents.

    Science.gov (United States)

    Tingey, Lauren; Larzelere-Hinton, Francene; Goklish, Novalene; Ingalls, Allison; Craft, Todd; Sprengeler, Feather; McGuire, Courtney; Barlow, Allison

    2016-01-01

    American Indian (AI) adolescents suffer the largest disparities in substance use and suicide. Predominating prevention models focus primarily on risk and utilize deficit-based approaches. The fields of substance use and suicide prevention research urge for positive youth development frameworks that are strength based and target change at individual and community levels. Entrepreneurship education is an innovative approach that reflects the gap in available programs. This paper describes the development and evaluation of a youth entrepreneurship education program in partnership with one AI community. We detail the curriculum, process evaluation results, and the randomized controlled trial evaluating its efficacy for increasing protective factors. Lessons learned may be applicable to other AI communities.

  11. Learning Theory Bases of Communicative Methodology and the Notional/Functional Syllabus

    OpenAIRE

    Jacqueline D., Beebe

    1992-01-01

    This paper examines the learning theories that underlie the philosophy and practices known as communicative language teaching methodology. These theories are identified first as a reaction against the behavioristic learning theory of audiolingualism. Approaches to syllabus design based on both the "weak" version of communicative language teaching-learning to use the second language-and the "strong" version-using the second language to learn it-are examined. The application of cognitive theory...

  12. The Application of Carl Rogers' Person-Centered Learning Theory to Web-Based Instruction.

    Science.gov (United States)

    Miller, Christopher T.

    This paper provides a review of literature that relates research on Carl Rogers' person-centered learning theory to Web-based learning. Based on the review of the literature, a set of criteria is described that can be used to determine how closely a Web-based course matches the different components of Rogers' person-centered learning theory. Using…

  13. Achievable Strength-Based Signal Detection in Quantity-Constrained PAM OOK Concentration-Encoded Molecular Communication.

    Science.gov (United States)

    Mahfuz, Mohammad Upal

    2016-10-01

    In this paper, the expressions of achievable strength-based detection probabilities of concentration-encoded molecular communication (CEMC) system have been derived based on finite pulsewidth (FP) pulse-amplitude modulated (PAM) on-off keying (OOK) modulation scheme and strength threshold. An FP-PAM system is characterized by its duty cycle α that indicates the fraction of the entire symbol duration the transmitter remains on and transmits the signal. Results show that the detection performance of an FP-PAM OOK CEMC system significantly depends on the statistical distribution parameters of diffusion-based propagation noise and intersymbol interference (ISI). Analytical detection performance of an FP-PAM OOK CEMC system under ISI scenario has been explained and compared based on receiver operating characteristics (ROC) for impulse (i.e., spike)-modulated (IM) and FP-PAM CEMC schemes. It is shown that the effects of diffusion noise and ISI on ROC can be explained separately based on their communication range-dependent statistics. With full duty cycle, an FP-PAM scheme provides significantly worse performance than an IM scheme. The paper also analyzes the performance of the system when duty cycle, transmission data rate, and quantity of molecules vary.

  14. A curvature theory for discrete surfaces based on mesh parallelity

    KAUST Repository

    Bobenko, Alexander Ivanovich; Pottmann, Helmut; Wallner, Johannes

    2009-01-01

    We consider a general theory of curvatures of discrete surfaces equipped with edgewise parallel Gauss images, and where mean and Gaussian curvatures of faces are derived from the faces' areas and mixed areas. Remarkably these notions are capable

  15. Pre-Game-Theory Based Information Technology (GAMBIT) Study

    National Research Council Canada - National Science Library

    Polk, Charles

    2003-01-01

    .... The generic GAMBIT scenario has been characterized as Dynamic Hierarchical Gaming (DHG). Game theory is not yet ready to fully support analysis of DHG, though existing partial analysis suggests that a full treatment is practical in the midterm...

  16. State variable theories based on Hart's formulation

    Energy Technology Data Exchange (ETDEWEB)

    Korhonen, M.A.; Hannula, S.P.; Li, C.Y.

    1985-01-01

    In this paper a review of the development of a state variable theory for nonelastic deformation is given. The physical and phenomenological basis of the theory and the constitutive equations describing macroplastic, microplastic, anelastic and grain boundary sliding enhanced deformation are presented. The experimental and analytical evaluation of different parameters in the constitutive equations are described in detail followed by a review of the extensive experimental work on different materials. The technological aspects of the state variable approach are highlighted by examples of the simulative and predictive capabilities of the theory. Finally, a discussion of general capabilities, limitations and future developments of the theory and particularly the possible extensions to cover an even wider range of deformation or deformation-related phenomena is presented.

  17. Effect of Reinforcement Using Stainless Steel Mesh, Glass Fibers, and Polyethylene on the Impact Strength of Heat Cure Denture Base Resin - An In Vitro Study.

    Science.gov (United States)

    Murthy, H B Mallikarjuna; Shaik, Sharaz; Sachdeva, Harleen; Khare, Sumit; Haralur, Satheesh B; Roopa, K T

    2015-06-01

    The impact strength of denture base resin is of great concern and many approaches have been made to strengthen acrylic resin dentures. The objective of this study was to compare the impact strength of the denture base resin with and without reinforcement and to evaluate the impact strength of denture base resin when reinforced with stainless steel mesh, glass fiber, and polyethylene fibers in the woven form. The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat cured polymethyl methacrylate resin. The specimens were divided into four groups (n = 10). Group I specimens or control group were not reinforced. Group II specimens were reinforced with stainless steel mesh and Group III and Group IV specimens were reinforced with three percent by weight of glass fibers and polyethylene fibers in weave form respectively. All the specimens were immersed in water for 1-week before testing. The impact strength was measured with falling weight impact testing machine. One-way analysis of variance and Tukey's post-hoc test were used for statistical analysis. Highest impact strength values were exhibited by the specimens reinforced with polyethylene fibers followed by glass fibers, stainless steel mesh, and control group. Reinforcement of maxillary complete dentures showed a significant increase in impact strength when compared to unreinforced dentures. Polyethylene fibers exhibit better impact strength followed by glass fibers and stainless steel mesh. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs) the impact strength of the denture bases can be increased effectively.

  18. Multicriteria decision-making analysis based methodology for predicting carbonate rocks' uniaxial compressive strength

    Directory of Open Access Journals (Sweden)

    Ersoy Hakan

    2012-10-01

    Full Text Available

    ABSTRACT

    Uniaxial compressive strength (UCS deals with materials' to ability to withstand axially-directed pushing forces and especially considered to be rock materials' most important mechanical properties. However, the UCS test is an expensive, very time-consuming test to perform in the laboratory and requires high-quality core samples having regular geometry. Empirical equations were thus proposed for predicting UCS as a function of rocks' index properties. Analytical hierarchy process and multiple regression analysis based methodology were used (as opposed to traditional linear regression methods on data-sets obtained from carbonate rocks in NE Turkey. Limestone samples ranging from Devonian to late Cretaceous ages were chosen; travertine-onyx samples were selected from morphological environments considering their surface environmental conditions Test results from experiments carried out on about 250 carbonate rock samples were used in deriving the model. While the hierarchy model focused on determining the most important index properties affecting on UCS, regression analysis established meaningful relationships between UCS and index properties; 0. 85 and 0. 83 positive coefficient correlations between the variables were determined by regression analysis. The methodology provided an appropriate alternative to quantitative estimation of UCS and avoided the need for tedious and time consuming laboratory testing


    RESUMEN

    La resistencia a la compresión uniaxial (RCU trata con la capacidad de los materiales para soportar fuerzas empujantes dirigidas axialmente y, especialmente, es considerada ser uno de las más importantes propiedades mecánicas de

  19. Two-body perturbation theory versus first order perturbation theory: A comparison based on the square-well fluid.

    Science.gov (United States)

    Mercier Franco, Luís Fernando; Castier, Marcelo; Economou, Ioannis G

    2017-12-07

    We show that the Zwanzig first-order perturbation theory can be obtained directly from a truncated Taylor series expansion of a two-body perturbation theory and that such truncation provides a more accurate prediction of thermodynamic properties than the full two-body perturbation theory. This unexpected result is explained by the quality of the resulting approximation for the fluid radial distribution function. We prove that the first-order and the two-body perturbation theories are based on different approximations for the fluid radial distribution function. To illustrate the calculations, the square-well fluid is adopted. We develop an analytical expression for the two-body perturbed Helmholtz free energy for the square-well fluid. The equation of state obtained using such an expression is compared to the equation of state obtained from the first-order approximation. The vapor-liquid coexistence curve and the supercritical compressibility factor of a square-well fluid are calculated using both equations of state and compared to Monte Carlo simulation data. Finally, we show that the approximation for the fluid radial distribution function given by the first-order perturbation theory provides closer values to the ones calculated via Monte Carlo simulations. This explains why such theory gives a better description of the fluid thermodynamic behavior.

  20. Justifying Design Decisions with Theory-based Design Principles

    OpenAIRE

    Schermann, Michael;Gehlert, Andreas;Pohl, Klaus;Krcmar, Helmut

    2014-01-01

    Although the role of theories in design research is recognized, we show that little attention has been paid on how to use theories when designing new artifacts. We introduce design principles as a new methodological approach to address this problem. Design principles extend the notion of design rationales that document how a design decision emerged. We extend the concept of design rationales by using theoretical hypotheses to support or object to design decisions. At the example of developing...

  1. Evaluation of SF6-alternative gas C5-PFK based on arc extinguishing performance and electric strength

    Science.gov (United States)

    Wu, Yi; Wang, Chunlin; Sun, Hao; Rong, Mingzhe; Murphy, Anthony Bruce; Li, Tianwei; Zhong, Jianying; Chen, Zhexin; Yang, Fei; Niu, Chunpin

    2017-09-01

    characteristics of the molecule. Based on the analysis of the molecular surface electrostatic potential and electric strength of C5-PFK, SF6, CF4, CO2, and N2, it is found that the positive potential area of the molecular surface has a strong correlation with the electric strength and is expected to be one of the predictors of electric strength. To verify this phenomenon, 36 kinds of particles were used for the correlation analysis. The correlation coefficient between the positive potential area and electric strength is up to 0.9 which means strong correlation.

  2. Strength Analysis of the Carbon-Fiber Reinforced Polymer Impeller Based on Fluid Solid Coupling Method

    Directory of Open Access Journals (Sweden)

    Jinbao Lin

    2014-01-01

    Full Text Available Carbon-fiber reinforced polymer material impeller is designed for the centrifugal pump to deliver corrosive, toxic, and abrasive media in the chemical and pharmaceutical industries. The pressure-velocity coupling fields in the pump are obtained from the CFD simulation. The stress distribution of the impeller couple caused by the flow water pressure and rotation centrifugal force of the blade is analyzed using one-way fluid-solid coupling method. Results show that the strength of the impeller can meet the requirement of the centrifugal pumps, and the largest stress occurred around the blades root on a pressure side of blade surface. Due to the existence of stress concentration at the blades root, the fatigue limit of the impeller would be reduced greatly. In the further structure optimal design, the blade root should be strengthened.

  3. CALCULATION METHOD OF ELECTRIC POWER LINES MAGNETIC FIELD STRENGTH BASED ON CYLINDRICAL SPATIAL HARMONICS

    Directory of Open Access Journals (Sweden)

    A.V. Erisov

    2016-05-01

    Full Text Available Purpose. Simplification of accounting ratio to determine the magnetic field strength of electric power lines, and assessment of their environmental safety. Methodology. Description of the transmission lines of the magnetic field by using techniques of spatial harmonic analysis in the cylindrical coordinate system is carried out. Results. For engineering calculations of electric power lines magnetic field with sufficient accuracy describes their first spatial harmonic magnetic field. Originality. Substantial simplification of the definition of the impact of the construction of transmission line poles on the value of its magnetic field and the bands of land alienation sizes. Practical value. The environmentally friendly projection electric power lines on the level of the magnetic field.

  4. Optimum Mix for Pervious Geopolymer Concrete (GEOCRETE Based on Water Permeability and Compressive Strength

    Directory of Open Access Journals (Sweden)

    Abdulsalam Arafa Salaheddin

    2017-01-01

    Full Text Available The production of ordinary Portland cement (OPC consumes considerable natural resources and energy, and it also affects the emission of a significant quantity of CO2 in the atmosphere. This pervious geopolymer concrete study aims to explore an alternative binder without OPC. Pervious geopolymer concretes were prepared from fly ash (FA, sodium silicate (NaSiO3, sodium hydroxide (NaOH solution, and coarse aggregate (CA. The effects of pervious geopolymer concrete parameters that affect water permeability and compressive strength are evaluated. The FA to CA ratios of 1:6, 1:7,1:8, and 1:9 by weight, CA sizes of 5–10, 10–14, and 14–20 mm, constant NaSiO3/NaOH ratio of 2.5, alkaline liquid to fly ash (AL/FA ratios of 0.4, 0.5, and 0.6, and NaOH concentrations of 8, 10, and 12 M were the pervious geopolymer concrete mix proportions. The curing temperature of 80 °C for 24 h was used. The results showed that a pervious geopolymer concrete with CA of 10 mm achieved water permeability of 2.3 cm/s and compressive strength of 20 MPa with AL/FA ratio of 0.5, NaOH concentration of 10 M, and FA:CA of 1:7. GEOCRETE is indicated to have better engineering properties than does pervious concrete that is made of ordinary Portland cement.

  5. Screen-Based Sedentary Behavior, Physical Activity, and Muscle Strength in the English Longitudinal Study of Ageing

    Science.gov (United States)

    Hamer, Mark; Stamatakis, Emmanuel

    2013-01-01

    Background Sarcopenia is associated with loss of independence and ill-health in the elderly although the causes remain poorly understood. We examined the association between two screen-based leisure time sedentary activities (daily TV viewing time and internet use) and muscle strength. Methods and Results We studied 6228 men and women (aged 64.9±9.1 yrs) from wave 4 (2008-09) of the English Longitudinal Study of Ageing, a prospective study of community dwelling older adults. Muscle strength was assessed by a hand grip test and the time required to complete five chair rises. TV viewing and internet usage were inversely associated with one another. Participants viewing TV ≥6hrs/d had lower grip strength (Men, B = −1.20 kg, 95% CI, −2.26, −0.14; Women, −0.75 kg, 95% CI, −1.48, −0.03) in comparison to behavior. PMID:23755302

  6. A prediction method based on grey system theory in equipment condition based maintenance

    International Nuclear Information System (INIS)

    Yan, Shengyuan; Yan, Shengyuan; Zhang, Hongguo; Zhang, Zhijian; Peng, Minjun; Yang, Ming

    2007-01-01

    Grey prediction is a modeling method based on historical or present, known or indefinite information, which can be used for forecasting the development of the eigenvalues of the targeted equipment system and setting up the model by using less information. In this paper, the postulate of grey system theory, which includes the grey generating, the sorts of grey generating and the grey forecasting model, is introduced first. The concrete application process, which includes the grey prediction modeling, grey prediction, error calculation, equal dimension and new information approach, is introduced secondly. Application of a so-called 'Equal Dimension and New Information' (EDNI) technology in grey system theory is adopted in an application case, aiming at improving the accuracy of prediction without increasing the amount of calculation by replacing old data with new ones. The proposed method can provide a new way for solving the problem of eigenvalue data exploding in equal distance effectively, short time interval and real time prediction. The proposed method, which was based on historical or present, known or indefinite information, was verified by the vibration prediction of induced draft fan of a boiler of the Yantai Power Station in China, and the results show that the proposed method based on grey system theory is simple and provides a high accuracy in prediction. So, it is very useful and significant to the controlling and controllable management in safety production. (authors)

  7. Screen-based sedentary behavior, physical activity, and muscle strength in the English longitudinal study of ageing.

    Directory of Open Access Journals (Sweden)

    Mark Hamer

    Full Text Available Sarcopenia is associated with loss of independence and ill-health in the elderly although the causes remain poorly understood. We examined the association between two screen-based leisure time sedentary activities (daily TV viewing time and internet use and muscle strength.We studied 6228 men and women (aged 64.9 ± 9.1 yrs from wave 4 (2008-09 of the English Longitudinal Study of Ageing, a prospective study of community dwelling older adults. Muscle strength was assessed by a hand grip test and the time required to complete five chair rises. TV viewing and internet usage were inversely associated with one another. Participants viewing TV ≥ 6 hrs/d had lower grip strength (Men, B = -1.20 kg, 95% CI, -2.26, -0.14; Women, -0.75 kg, 95% CI, -1.48, -0.03 in comparison to <2 hrs/d TV, after adjustment for age, physical activity, smoking, alcohol, chronic disease, disability, depressive symptoms, social status, and body mass index. In contrast, internet use was associated with higher grip strength (Men, B = 2.43 kg, 95% CI, 1.74, 3.12; Women, 0.76 kg, 95% CI, 0.32, 1.20. These associations persisted after mutual adjustment for both types of sedentary behaviour.In older adults, the association between sedentary activities and physical function is context specific (TV viewing vs. computer use. Adverse effects of TV viewing might reflect the prolonged sedentary nature of this behavior.

  8. The effect of aerobic versus strength-based training on high-sensitivity C-reactive protein in older adults.

    Science.gov (United States)

    Martins, Raul A; Neves, Ana P; Coelho-Silva, Manuel J; Veríssimo, Manuel T; Teixeira, Ana Maria

    2010-09-01

    Increased levels of inflammatory markers, namely, high-sensitive C-reactive protein (hs-CRP), have been associated with several chronic diseases including atherosclerosis, type 2 diabetes and hypertension. Forty-five women and men aged >64 years participated in the study and were randomly assigned to two exercise intervention groups and a non-exercising control group. The participants assigned to the exercising groups followed a 16-week exercise protocol based either on aerobic training (AT) or strength training (ST) followed by a further 16 weeks off-training period. The control group (C) remained sedentary throughout the study. Evaluation of body mass, BMI, waist circumference, aerobic endurance, lower-body strength, upper-body strength, triglycerides, total cholesterol, LDL-cholesterol, HDL-cholesterol and hs-CRP were performed at baseline, after 16 weeks (post-training for the exercise groups) and at 32 weeks (follow-up). Both, AT and ST groups significantly increased functional fitness at the end of the exercise programs when compared to baseline values. hs-CRP concentrations were maintained throughout the study for the C group, while decreasing 10% at 16 weeks and 51% at 32 weeks for the AT group. In the ST group the hs-CRP concentrations decreased by 11 and 39% at 16 and 32 weeks, respectively. Decreases in hs-CRP concentrations were statistically significant for the AT and ST groups at the 32-week evaluation when compared to baseline. Reduction in hs-CRP concentrations seemed to be associated with strength gains and adiposity loss.

  9. Hip and knee strength is not affected in 12-16 year old adolescents with patellofemoral pain - a cross-sectional population-based study

    DEFF Research Database (Denmark)

    Rathleff, Camilla Rams; Baird, William Neill; Olesen, Jens Lykkegaard

    2013-01-01

    One of the rationales behind using strength training in the treatment of adolescents with Patellofemoral Pain (PFP) is that reduced strength of the lower extremity is a risk factor for PFP and a common deficit. This rationale is based on research conducted on adolescents >15 years of age but has...

  10. Wavelet-based linear-response time-dependent density-functional theory

    Science.gov (United States)

    Natarajan, Bhaarathi; Genovese, Luigi; Casida, Mark E.; Deutsch, Thierry; Burchak, Olga N.; Philouze, Christian; Balakirev, Maxim Y.

    2012-06-01

    Linear-response time-dependent (TD) density-functional theory (DFT) has been implemented in the pseudopotential wavelet-based electronic structure program BIGDFT and results are compared against those obtained with the all-electron Gaussian-type orbital program DEMON2K for the calculation of electronic absorption spectra of N2 using the TD local density approximation (LDA). The two programs give comparable excitation energies and absorption spectra once suitably extensive basis sets are used. Convergence of LDA density orbitals and orbital energies to the basis-set limit is significantly faster for BIGDFT than for DEMON2K. However the number of virtual orbitals used in TD-DFT calculations is a parameter in BIGDFT, while all virtual orbitals are included in TD-DFT calculations in DEMON2K. As a reality check, we report the X-ray crystal structure and the measured and calculated absorption spectrum (excitation energies and oscillator strengths) of the small organic molecule N-cyclohexyl-2-(4-methoxyphenyl)imidazo[1, 2-a]pyridin-3-amine.

  11. Theory of Planned Behavior in School-Based Adolescent Problem Gambling Prevention: A Conceptual Framework.

    Science.gov (United States)

    St-Pierre, Renée A; Temcheff, Caroline E; Derevensky, Jeffrey L; Gupta, Rina

    2015-12-01

    Given its serious implications for psychological and socio-emotional health, the prevention of problem gambling among adolescents is increasingly acknowledged as an area requiring attention. The theory of planned behavior (TPB) is a well-established model of behavior change that has been studied in the development and evaluation of primary preventive interventions aimed at modifying cognitions and behavior. However, the utility of the TPB has yet to be explored as a framework for the development of adolescent problem gambling prevention initiatives. This paper first examines the existing empirical literature addressing the effectiveness of school-based primary prevention programs for adolescent gambling. Given the limitations of existing programs, we then present a conceptual framework for the integration of the TPB in the development of effective problem gambling preventive interventions. The paper describes the TPB, demonstrates how the framework has been applied to gambling behavior, and reviews the strengths and limitations of the model for the design of primary prevention initiatives targeting adolescent risk and addictive behaviors, including adolescent gambling.

  12. Buckling analysis of orthotropic protein microtubules under axial and radial compression based on couple stress theory.

    Science.gov (United States)

    Beni, Yaghoub Tadi; Zeverdejani, M Karimi; Mehralian, Fahimeh

    2017-10-01

    Protein microtubules (MTs) are one of the important intercellular components and have a vital role in the stability and strength of the cells. Due to applied external loads, protein microtubules may be involved buckling phenomenon. Due to impact of protein microtubules in cell reactions, it is important to determine their critical buckling load. Considering nature of protein microtubules, various parameters are effective on microtubules buckling. The small size of microtubules and also lack of uniformity of MTs properties in different directions caused the necessity of accuracy in the analysis of these bio-structure. In fact, microtubules must be considered as a size dependent cylinder, which behave as an orthotropic material. Hence, in the present work using first-order shear deformation model (FSDT), the buckling equations of anisotropic MTs are derived based on new modified couple stress theory (NMCST). After solving the stability equations, the influences of various parameters are measured on the MTs critical buckling load. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Approach to the nonrelatiVistic scattering theory based on the causality superposition and unitarity principles

    International Nuclear Information System (INIS)

    Gajnutdinov, R.Kh.

    1983-01-01

    Possibility is studied to build the nonrelativistic scattering theory on the base of the general physical principles: causality, superposition, and unitarity, making no use of the Schroedinger formalism. The suggested approach is shown to be more general than the nonrelativistic scattering theory based on the Schroedinger equation. The approach is applied to build a model ofthe scattering theory for a system which consists of heavy nonrelativistic particles and a light relativistic particle

  14. Magma explains low estimates of lithospheric strength based on flexure of ocean island loads

    Science.gov (United States)

    Buck, W. Roger; Lavier, Luc L.; Choi, Eunseo

    2015-04-01

    One of the best ways to constrain the strength of the Earth's lithosphere is to measure the deformation caused by large, well-defined loads. The largest, simple vertical load is that of the Hawaiian volcanic island chain. An impressively detailed recent analysis of the 3D response to that load by Zhong and Watts (2013) considers the depth range of seismicity below Hawaii and the seismically determined geometry of lithospheric deflection. These authors find that the friction coefficient for the lithosphere must be in the normal range measured for rocks, but conclude that the ductile flow strength has to be far weaker than laboratory measurements suggest. Specifically, Zhong and Watts (2013) find that stress differences in the mantle lithosphere below the island chain are less than about 200 MPa. Standard rheologic models suggest that for the ~50 km thick lithosphere inferred to exist below Hawaii yielding will occur at stress differences of about 1 GPa. Here we suggest that magmatic accommodation of flexural extension may explain Hawaiian lithospheric deflection even with standard mantle flow laws. Flexural stresses are extensional in the deeper part of the lithosphere below a linear island load (i.e. horizontal stresses orthogonal to the line load are lower than vertical stresses). Magma can accommodate lithospheric extension at smaller stress differences than brittle and ductile rock yielding. Dikes opening parallel to an island chain would allow easier downflexing than a continuous plate, but wound not produce a freely broken plate. The extensional stress needed to open dikes at depth depends on the density contrast between magma and lithosphere, assuming magma has an open pathway to the surface. For a uniform lithospheric density ρL and magma density ρM the stress difference to allow dikes to accommodate extension is: Δσxx (z) = g z (ρM - gρL), where g is the acceleration of gravity and z is depth below the surface. For reasonable density values (i.e.

  15. Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

    OpenAIRE

    Kurzawa A.; Kaczmar J.W.

    2017-01-01

    The paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3 particles of 3-6μm with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by ...

  16. Compressive Strength of EN AC-44200 Based Composite Materials Strengthened with α-Al2O3 Particles

    OpenAIRE

    Kurzawa A.; Kaczmar J. W.

    2017-01-01

    The paper presents results of compressive strength investigations of EN AC-44200 based aluminum alloy composite materials reinforced with aluminum oxide particles at ambient and at temperatures of 100, 200 and 250°C. They were manufactured by squeeze casting of the porous preforms made of α-Al2O3 particles with liquid aluminum alloy EN AC-44200. The composite materials were reinforced with preforms characterized by the porosities of 90, 80, 70 and 60 vol. %, thus the alumina content in the co...

  17. Effect of repair resin type and surface treatment on the repair strength of heat-polymerized denture base resin.

    Science.gov (United States)

    Alkurt, Murat; Yeşil Duymuş, Zeynep; Gundogdu, Mustafa

    2014-01-01

    Acrylic resin denture fracture is common in prosthodontic practice. When fractured denture bases are repaired, recurrent fractures frequently occur at the repair surface interface or adjacent areas. The purpose of this study was to evaluate the effect of different surface treatments on the flexural strength of the acrylic resin denture base repaired with heat-polymerized acrylic resin, autopolymerizing resin, and light-polymerized acrylic resin. Ninety-six specimens of heat-polymerized acrylic resin were prepared according to the American Dental Association Specification No. 12 (65.0 × 10.0 × 2.5 mm) and sectioned into halves to create a repair gap (3.0 × 10 × 2.5 mm). The sectioned specimens were divided into 3 groups according to their repair materials. The specimens from each group were divided into 4 subgroups according to their surface treatments: a control group without any surface treatment; an experimental group treated with methyl methacrylate monomer (MMA group); an experimental group treated with airborne-particle abrasion with aluminum oxide particles of 250-μm particle size (abrasion group); and an experimental group treated with erbium:yttrium-aluminum-garnet laser (laser group). After the surface treatments, the 3 materials were placed into the repair gaps and then polymerized. After all of the specimens had been ground and polished, they were stored in distilled water at 37°C for 1 week and subjected to a 3-point bend test. Data were analyzed with a 2-way analysis of variance, and the Tukey honestly significant difference test was performed to identify significant differences (α=.05). The effects of the surface treatments and repair resins on the surface of the denture base resin were examined with scanning electron microscopy. Significant differences were found among the groups in terms of repair resin type (P<.001). All surface-treated specimens had higher flexural strength than controls, except the surface treated with the methyl

  18. Practice what you preach: developing person-centred culture in inpatient mental health settings through strengths-based, transformational leadership.

    Science.gov (United States)

    Beckett, Paul; Field, John; Molloy, Luke; Yu, Nickolas; Holmes, Douglas; Pile, Emily

    2013-08-01

    The experience of nursing staff and consumers in inpatient mental health wards is often reported as being negative. Efforts to improve culture and practice have had limited success, with ineffective leadership, staff resistance, and unresponsive organisational culture identified as common barriers to change. Practice development has been promoted as an approach to developing person-centred culture that enables professional development through participation, learning and empowerment. For person-centred practice to flourish, organisational leadership at all levels must reflect the same principles. In preparation for the opening of a new integrated mental health service, an inpatient mental health team participated in a practice development project. An action research approach was used to facilitate a series of "away days," initially with the nursing team and then other members of the multidisciplinary team (MDT). Transformational leadership principles were adopted in the facilitation of team activities underpinned by strengths and solution-focused practices. Evaluation of the project by staff members was very positive and there was a high level of participation in practice development activities. The project resulted in the creation of a development plan for the ward, which prioritised five key themes: person-centred care, personal recovery, strengths-based principles, and evidence-based and values-based care. The project outcomes highlight the importance of leadership, which parallels the ideals promoted for clinical practice.

  19. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.

    Science.gov (United States)

    Dang, B; Zhang, X; Chen, Y Z; Chen, C X; Wang, H T; Liu, F

    2016-08-09

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

  20. Chlorhexidine and proanthocyanidin enhance the long-term bond strength of resin-based endodontic sealer

    Directory of Open Access Journals (Sweden)

    Thaís Fantinato Trindade

    2018-05-01

    Full Text Available Abstract The aim of this study was to evaluate the effects of proanthocyanidin (PA and chlorhexidine (CHX on the bond strength (BS, failure pattern, and resin-dentin interface morphology of the endodontic sealers EndoREZ and AH Plus after 24 h and 6 months of water storage. A total of 120 prepared bovine roots were divided into six groups: AH Plus, CHX+AH Plus, PA+AH Plus, EndoREZ, CHX+EndoREZ, and PA+EndoREZ. Dentin was treated for 1 or 5 min with 2% CHX or 15% PA, respectively. Roots were filled and stored in water for 24 h or 6 months (n = 10. Root slices were subjected to push-out test and scanning electron microscopy (SEM. Data were compared using two-way ANOVA and student's t-test (α = 5%. BS decreased over time for AH Plus and untreated EndoREZ (p 0.05. At 6 months, EndoREZ had higher BS values for CHX and PA than control (p 0.05. Cohesive and mixed failures were observed in all groups. SEM revealed sealer tags in the root dentin. In conclusion, BS decreased with time and AH Plus had higher BS than EndoREZ in untreated dentin; however, CHX or PA enhanced long-term BS of EndoREZ. Overall, dentin treatment affected failure pattern and resin-dentin interface morphology, particularly for EndoREZ.

  1. Strength, leachability and microstructure characteristics of cement-based solidified plating sludge

    International Nuclear Information System (INIS)

    Asavapisit, Suwimol; Naksrichum, Siripat; Harnwajanawong, Naraporn

    2005-01-01

    The solidification of the stabilized zinc-cyanide plating sludge was carried out using ordinary Portland cement (OPC) and pulverized fuel ash (PFA) as solidification binders. The plating sludge were used at the level of 0%, 10%, 20% and 30% dry weight, and PFA was used to replace OPC at 0%, 10%, 20% and 30% dry weight, respectively. Experimental results showed that a significant reduction in strength was observed when the plating sludge was added to both the OPC and OPC/PFA binders, but the negative effect was minimized when PFA was used as part substitute for OPC. SEM observation reveals that the deposition of the plating sludge on the surface of the clinkers and PFA could be the cause for hydration retardation. In addition, calcium zinc hydroxide hydrate complex and the unreacted di- and tricalcium silicates were the major phases in X-ray diffraction (XRD) patterns of the solidified plating waste hydrated for 28 days, although the retardation effect on hydration reactions but Cr concentration in toxicity characteristic leaching procedure (TCLP) leachates was lower than the U.S. EPA regulatory limit

  2. Enhancing Student Learning in Knowledge-Based Courses: Integrating Team-Based Learning in Mass Communication Theory Classes

    Science.gov (United States)

    Han, Gang; Newell, Jay

    2014-01-01

    This study explores the adoption of the team-based learning (TBL) method in knowledge-based and theory-oriented journalism and mass communication (J&MC) courses. It first reviews the origin and concept of TBL, the relevant theories, and then introduces the TBL method and implementation, including procedures and assessments, employed in an…

  3. Theory of sampling and its application in tissue based diagnosis

    Directory of Open Access Journals (Sweden)

    Kayser Gian

    2009-02-01

    Full Text Available Abstract Background A general theory of sampling and its application in tissue based diagnosis is presented. Sampling is defined as extraction of information from certain limited spaces and its transformation into a statement or measure that is valid for the entire (reference space. The procedure should be reproducible in time and space, i.e. give the same results when applied under similar circumstances. Sampling includes two different aspects, the procedure of sample selection and the efficiency of its performance. The practical performance of sample selection focuses on search for localization of specific compartments within the basic space, and search for presence of specific compartments. Methods When a sampling procedure is applied in diagnostic processes two different procedures can be distinguished: I the evaluation of a diagnostic significance of a certain object, which is the probability that the object can be grouped into a certain diagnosis, and II the probability to detect these basic units. Sampling can be performed without or with external knowledge, such as size of searched objects, neighbourhood conditions, spatial distribution of objects, etc. If the sample size is much larger than the object size, the application of a translation invariant transformation results in Kriege's formula, which is widely used in search for ores. Usually, sampling is performed in a series of area (space selections of identical size. The size can be defined in relation to the reference space or according to interspatial relationship. The first method is called random sampling, the second stratified sampling. Results Random sampling does not require knowledge about the reference space, and is used to estimate the number and size of objects. Estimated features include area (volume fraction, numerical, boundary and surface densities. Stratified sampling requires the knowledge of objects (and their features and evaluates spatial features in relation to

  4. Models for Theory-Based M.A. and Ph.D. Programs.

    Science.gov (United States)

    Botan, Carl; Vasquez, Gabriel

    1999-01-01

    Presents work accomplished at the 1998 National Communication Association Summer Conference. Outlines reasons for theory-based education in public relations. Presents an integrated model of student outcomes, curriculum, pedagogy, and assessment for theory-based master's and doctoral programs, including assumptions made and rationale for such…

  5. Application of γ field theory based calculation method to the monitoring of mine nuclear radiation environment

    International Nuclear Information System (INIS)

    Du Yanjun; Liu Qingcheng; Liu Hongzhang; Qin Guoxiu

    2009-01-01

    In order to find the feasibility of calculating mine radiation dose based on γ field theory, this paper calculates the γ radiation dose of a mine by means of γ field theory based calculation method. The results show that the calculated radiation dose is of small error and can be used to monitor mine environment of nuclear radiation. (authors)

  6. Automatic Trading Agent. RMT Based Portfolio Theory and Portfolio Selection

    Science.gov (United States)

    Snarska, M.; Krzych, J.

    2006-11-01

    Portfolio theory is a very powerful tool in the modern investment theory. It is helpful in estimating risk of an investor's portfolio, arosen from lack of information, uncertainty and incomplete knowledge of reality, which forbids a perfect prediction of future price changes. Despite of many advantages this tool is not known and not widely used among investors on Warsaw Stock Exchange. The main reason for abandoning this method is a high level of complexity and immense calculations. The aim of this paper is to introduce an automatic decision-making system, which allows a single investor to use complex methods of Modern Portfolio Theory (MPT). The key tool in MPT is an analysis of an empirical covariance matrix. This matrix, obtained from historical data, biased by such a high amount of statistical uncertainty, that it can be seen as random. By bringing into practice the ideas of Random Matrix Theory (RMT), the noise is removed or significantly reduced, so the future risk and return are better estimated and controlled. These concepts are applied to the Warsaw Stock Exchange Simulator {http://gra.onet.pl}. The result of the simulation is 18% level of gains in comparison with respective 10% loss of the Warsaw Stock Exchange main index WIG.

  7. Effective Contraceptive Use: An Exploration of Theory-Based Influences

    Science.gov (United States)

    Peyman, N.; Oakley, D.

    2009-01-01

    The purpose of this study was to explore factors that influence oral contraceptive (OC) use among women in Iran using the Theory of Planned Behavior (TPB) and concept of self-efficacy (SE). The study sample consisted of 360 married OC users, aged 18-49 years recruited at public health centers of Mashhad, 900 km east of Tehran. SE had the strongest…

  8. Videogames, Tools for Change: A Study Based on Activity Theory

    Science.gov (United States)

    Méndez, Laura; Lacasa, Pilar

    2015-01-01

    Introduction: The purpose of this study is to provide a framework for analysis from which to interpret the transformations that take place, as perceived by the participants, when commercial video games are used in the classroom. We will show how Activity Theory (AT) is able to explain and interpret these changes. Method: Case studies are…

  9. Strength evaluation code STEP for brittle materials

    International Nuclear Information System (INIS)

    Ishihara, Masahiro; Futakawa, Masatoshi.

    1997-12-01

    In a structural design using brittle materials such as graphite and/or ceramics it is necessary to evaluate the strength of component under complex stress condition. The strength of ceramic materials is said to be influenced by the stress distribution. However, in the structural design criteria simplified stress limits had been adopted without taking account of the strength change with the stress distribution. It is, therefore, important to evaluate the strength of component on the basis of the fracture model for brittle material. Consequently, the strength evaluation program, STEP, on a brittle fracture of ceramic materials based on the competing risk theory had been developed. Two different brittle fracture modes, a surface layer fracture mode dominated by surface flaws and an internal fracture mode by internal flaws, are treated in the STEP code in order to evaluate the strength of brittle fracture. The STEP code uses stress calculation results including complex shape of structures analyzed by the generalized FEM stress analysis code, ABAQUS, so as to be possible to evaluate the strength of brittle fracture for the structures having complicate shapes. This code is, therefore, useful to evaluate the structural integrity of arbitrary shapes of components such as core graphite components in the HTTR, heat exchanger components made of ceramics materials etc. This paper describes the basic equations applying to the STEP code, code system with a combination of the STEP and the ABAQUS codes and the result of the verification analysis. (author)

  10. The Electrophysiological Signature of Remember-Know Is Confounded with Memory Strength and Cannot Be Interpreted as Evidence for Dual-process Theory of Recognition.

    Science.gov (United States)

    Brezis, Noam; Bronfman, Zohar Z; Yovel, Galit; Goshen-Gottstein, Yonatan

    2017-02-01

    The quantity and nature of the processes underlying recognition memory remains an open question. A majority of behavioral, neuropsychological, and brain studies have suggested that recognition memory is supported by two dissociable processes: recollection and familiarity. It has been conversely argued, however, that recollection and familiarity map onto a single continuum of mnemonic strength and hence that recognition memory is mediated by a single process. Previous electrophysiological studies found marked dissociations between recollection and familiarity, which have been widely held as corroborating the dual-process account. However, it remains unknown whether a strength interpretation can likewise apply for these findings. Here we describe an ERP study, using a modified remember-know (RK) procedure, which allowed us to control for mnemonic strength. We find that ERPs of high and low mnemonic strength mimicked the electrophysiological distinction between R and K responses, in a lateral positive component (LPC), 500-1000 msec poststimulus onset. Critically, when contrasting strength with RK experience, by comparing weak R to strong K responses, the electrophysiological signal mapped onto strength, not onto subjective RK experience. Invoking the LPC as support for dual-process accounts may, therefore, be amiss.

  11. Theory and theory-based models for the pedestal, edge stability and ELMs in tokamaks

    International Nuclear Information System (INIS)

    Guzdar, P.N.; Mahajan, S.M.; Yoshida, Z.; Dorland, W.; Rogers, B.N.; Bateman, G.; Kritz, A.H.; Pankin, A.; Voitsekhovitch, I.; Onjun, T.; Snyder, S.

    2005-01-01

    Theories for equilibrium and stability of H-modes, and models for use within integrated modeling codes with the objective of predicting the height, width and shape of the pedestal at the edge of H-mode plasmas in tokamaks, as well as the onset and frequency of Edge Localized Modes (ELMs), are developed. A theory model for relaxed plasma states with flow, which uses two-fluid Hall-MHD equations, predicts that the natural scale length of the pedestal is the ion skin depth and the pedestal width is larger than the ion poloidal gyro-radius, in agreement with experimental observations. Computations with the GS2 code are used to identify micro-instabilities, such as electron drift waves, that survive the strong flow shear, diamagnetic flows, and magnetic shear that are characteristic of the pedestal. Other instabilities on the pedestal and gyro-radius scale, such as the Kelvin-Helmholtz instability, are also investigated. Time-dependent integrated modeling simulations are used to follow the transition from L-mode to H-mode and the subsequent evolution of ELMs as the heating power is increased. The flow shear stabilization that produces the transport barrier at the edge of the plasma reduces different modes of anomalous transport and, consequently, different channels of transport at different rates. ELM crashes are triggered in the model by pressure-driven ballooning modes or by current-driven peeling modes. (author)

  12. 3D Progressive Damage Modeling for Laminated Composite Based on Crack Band Theory and Continuum Damage Mechanics

    Science.gov (United States)

    Wang, John T.; Pineda, Evan J.; Ranatunga, Vipul; Smeltzer, Stanley S.

    2015-01-01

    A simple continuum damage mechanics (CDM) based 3D progressive damage analysis (PDA) tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code. This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al.'s formulation to incorporate the degrading material properties into the damaged stiffness matrix. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions. This CDM based PDA tool is implemented as a user defined material (VUMAT) to link with the Abaqus/Explicit code. Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads.

  13. The influence of different bracket base surfaces on tensile and shear bond strength

    NARCIS (Netherlands)

    Algera, T.J.; Kleverlaan, C.J.; Prahl-Andersen, B.; Feilzer, A.J.

    2008-01-01

    Fracture of the bracket-cement-enamel system usually takes place between the bracket and the cement. Especially for glass ionomer-based materials, it is helpful if this part of the system can be improved. The aim of this in vitro study was to investigate the influence of different bracket base

  14. Impact Strength of Composite Materials Based on EN AC-44200 Matrix Reinforced with Al2O3 Particles

    Directory of Open Access Journals (Sweden)

    Kurzawa A.

    2017-09-01

    Full Text Available The paper presents the results of research of impact strength of aluminum alloy EN AC-44200 based composite materials reinforced with alumina particles. The research was carried out applying the materials produced by the pressure infiltration method of ceramic preforms made of Al2O3 particles of 3-6μm with the liquid EN AC-44200 Al alloy. The research was aimed at determining the composite resistance to dynamic loads, taking into account the volume of reinforcing particles (from 10 to 40% by volume at an ambient of 23°C and at elevated temperatures to a maximum of 300°C. The results of this study were referred to the unreinforced matrix EN AC-44200 and to its hardness and tensile strength. Based on microscopic studies, an analysis and description of crack mechanics of the tested materials were performed. Structural analysis of a fracture surface, material structures under the crack surfaces of the matrix and cracking of the reinforcing particles were performed.

  15. Determination of the electric field strength of filamentary DBDs by CARS-based four-wave mixing

    Science.gov (United States)

    Böhm, P.; Kettlitz, M.; Brandenburg, R.; Höft, H.; Czarnetzki, U.

    2016-10-01

    It is demonstrated that a four-wave mixing technique based on coherent anti-Stokes Raman spectroscopy (CARS) can determine the electric field strength of a pulsed-driven filamentary dielectric barrier discharge (DBD) of 1 mm gap, using hydrogen as a tracer medium in nitrogen at atmospheric pressure. The measurements are presented for a hydrogen admixture of 10%, but even 5% H2 admixture delivers sufficient infrared signals. The lasers do not affect the discharge by photoionization or by other radiation-induced processes. The absolute values of the electric field strength can be determined by the calibration of the CARS setup with high voltage amplitudes below the ignition threshold of the arrangement. This procedure also enables the determination of the applied breakdown voltage. The alteration of the electric field is observed during the internal polarity reversal and the breakdown process. One advantage of the CARS technique over emission-based methods is that it can be used independently of emission, e.g. in the pre-phase and in between two consecutive discharges, where no emission occurs at all.

  16. Dike Strength Analysis on a Regional Scale Based On a Stochastic Subsoil Model

    Science.gov (United States)

    Koelewijn, A. R.; Vastenburg, E. W.

    2013-12-01

    [Knoeff et al. 2011] J.G. Knoeff, E.W. Vastenburg, G.A. van den Ham & J. Lopez de la Cruz, Automated levee flood risk management, 5th Int. Conf. on Flood Management, Tokyo, 2011 [Koelewijn et al. 2011] A.R. Koelewijn, G.A.M. Kruse & J. Pruiksma, Stochastic subsoil modelling - first set-up of the model and reliability analyses, report 12042000-002-HYE-0001, Deltares, Delft, 2011 [In Dutch] [Lam et al. 2013] K.S. Lam, P.W. Gill & L.W.A. Zwang, Implementation of new levee strength modules for continuous safety assessments, Comprehensive Flood Risk Managment, Taylor & Francis, London, 2013, 317-326. Dike sections with stochastic subsoil profiles.

  17. Detection of network attacks based on adaptive resonance theory

    Science.gov (United States)

    Bukhanov, D. G.; Polyakov, V. M.

    2018-05-01

    The paper considers an approach to intrusion detection systems using a neural network of adaptive resonant theory. It suggests the structure of an intrusion detection system consisting of two types of program modules. The first module manages connections of user applications by preventing the undesirable ones. The second analyzes the incoming network traffic parameters to check potential network attacks. After attack detection, it notifies the required stations using a secure transmission channel. The paper describes the experiment on the detection and recognition of network attacks using the test selection. It also compares the obtained results with similar experiments carried out by other authors. It gives findings and conclusions on the sufficiency of the proposed approach. The obtained information confirms the sufficiency of applying the neural networks of adaptive resonant theory to analyze network traffic within the intrusion detection system.

  18. Stability of boundary layer flow based on energy gradient theory

    Science.gov (United States)

    Dou, Hua-Shu; Xu, Wenqian; Khoo, Boo Cheong

    2018-05-01

    The flow of the laminar boundary layer on a flat plate is studied with the simulation of Navier-Stokes equations. The mechanisms of flow instability at external edge of the boundary layer and near the wall are analyzed using the energy gradient theory. The simulation results show that there is an overshoot on the velocity profile at the external edge of the boundary layer. At this overshoot, the energy gradient function is very large which results in instability according to the energy gradient theory. It is found that the transverse gradient of the total mechanical energy is responsible for the instability at the external edge of the boundary layer, which induces the entrainment of external flow into the boundary layer. Within the boundary layer, there is a maximum of the energy gradient function near the wall, which leads to intensive flow instability near the wall and contributes to the generation of turbulence.

  19. THE RESPONSIBILITY TO PROTECT. A JUST WAR THEORY BASED ANALYSIS

    Directory of Open Access Journals (Sweden)

    Andreea IANCU

    2014-11-01

    Full Text Available This paper analyzes the Responsibility to protect principle as the paradigm that reinforces the just war theory in the current international relations. The importance of this analysis is given by the fact that in the current change of source of international conflicts, the Responsibility to protect principle affirms the responsibility of the international community to protect all the citizens of the world. In this context we witness a translation toward a Post-Westphalian international system, which values the individual as a security referent. This article discusses the origins of the responsibility to protect principle and problematizes (discusses the legitimacy of use of violence and force in the current international system. Moreover, the paper analyzes the possible humanization of the current international relations and, simultaneously, the persistency of conflict and warfare in the international system. The conclusion of this research states that the Responsibility to protect principle revises the just war theory by centering it on the individual.

  20. Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins

    Directory of Open Access Journals (Sweden)

    Nour M. Ajaj-ALKordy

    2014-01-01

    Conclusion: Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture.