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Sample records for graded materials fgms

  1. A Review on Functionally Gradient Materials (FGMs) and Their Applications

    Science.gov (United States)

    Bhavar, Valmik; Kattire, Prakash; Thakare, Sandeep; patil, Sachin; Singh, RKP, Dr.

    2017-09-01

    Functionally gradient materials (FGM) are innovative materials in which final properties varies gradually with dimensions. It is the recent development in traditional composite materials which retains their strengths and eliminates their weaknesses. It can be formed by varying chemical composition, microstructure or design attributes from one end to other as per requirement. This feature allows FGM to have best material properties in required quantities only where it is needed. Though there are several methods available for manufacturing FGMs, additive based metal deposition (by laser, electron beam, plasma etc.) technologies are reaping particular interest owing to their recent developments. This paper presents evolution, current status and challenges of functionally gradient materials (FGMs). Various manufacturing processes of different types of FGMs are also presented. In addition, applications of FGMs in various fields including aerospace, defence, mining, power and tools manufacturing sectors are discussed in detail.

  2. Functionally Graded Materials Database

    Science.gov (United States)

    Kisara, Katsuto; Konno, Tomomi; Niino, Masayuki

    2008-02-01

    Functionally Graded Materials Database (hereinafter referred to as FGMs Database) was open to the society via Internet in October 2002, and since then it has been managed by the Japan Aerospace Exploration Agency (JAXA). As of October 2006, the database includes 1,703 research information entries with 2,429 researchers data, 509 institution data and so on. Reading materials such as "Applicability of FGMs Technology to Space Plane" and "FGMs Application to Space Solar Power System (SSPS)" were prepared in FY 2004 and 2005, respectively. The English version of "FGMs Application to Space Solar Power System (SSPS)" is now under preparation. This present paper explains the FGMs Database, describing the research information data, the sitemap and how to use it. From the access analysis, user access results and users' interests are discussed.

  3. Functionally graded materials produced by laser cladding

    NARCIS (Netherlands)

    Pei, Y.T.; Hosson, J.Th.M. De

    2000-01-01

    AlSi40 functionally graded materials (FGMs) were produced by a one-step laser cladding process on cast Al-alloy substrate as a possible solution for interfacial problems often present in laser coatings. The microstructure of the FGMs consists of a large amount of silicon primary particles surrounded

  4. A Novel Fabrication Method for Functionally Graded Materials under Centrifugal Force: The Centrifugal Mixed-Powder Method

    Directory of Open Access Journals (Sweden)

    Eri Miura-Fujiwara

    2009-12-01

    Full Text Available One of the fabrication methods for functionally graded materials (FGMs is a centrifugal solid-particle method, which is an application of the centrifugal casting technique. However, it is the difficult to fabricate FGMs containing nano-particles by the centrifugal solid-particle method. Recently, we proposed a novel fabrication method, which we have named the centrifugal mixed-powder method, by which we can obtain FGMs containing nano-particles. Using this processing method, Cu-based FGMs containing SiC particles and Al-based FGMs containing TiO2 nano-particles on their surfaces have been fabricated. In this article, the microstructure and mechanical property of Cu/SiC and Al/TiO2 FGMs, fabricated by the centrifugal mixed-powder method are reviewed.

  5. Achieving Functionally Graded Material Composition Through Bicontinuous Mesostructural Geometry in Material Extrusion Additive Manufacturing

    Science.gov (United States)

    Stoner, Brant; Bartolai, Joseph; Kaweesa, Dorcas V.; Meisel, Nicholas A.; Simpson, Timothy W.

    2018-03-01

    Functionally graded materials (FGMs) gradually change composition throughout their volume, allowing for areas of a part to be optimized for specific performance requirements. While additive manufacturing (AM) process types such as material jetting and directed energy deposition are capable of creating FGMs, design guidelines for varying the material composition in an FGM do not exist. This article presents a novel design solution for FGMs: creating the material gradient by varying the mesostructural size and thickness of bicontinuous, multi-material geometries. By using a bicontinuous structure, such as Schoen's gyroid surface or Schwarz's P and D surfaces, each component material exists as a continuous discrete structure, which allows FGMs to be fabricated by a wider range of AM processes. The gradient is created by varying the volume fraction occupied by the surface structure inside the part volume. This article explores the use of this technique to create FGMs with material extrusion AM. Properties of these bicontinuous structures are experimentally characterized and shown to outperform typical material extrusion FGMs.

  6. a Quadratic Layer Element for Analyzing Stress Waves in Fgms and its Application in Material Characterization

    Science.gov (United States)

    HAN, X.; LIU, G. R.; LAM, K. Y.; OHYOSHI, T.

    2000-09-01

    A novel method is presented for investigating elastic waves in functionally graded material (FGM) plates excited by plane pressure waves. The FGM plate is first divided into quadratic layer elements (QLEs). A general solution for the equation of motion governing the QLE has been derived. The general solution is then used together with the boundary and continuity conditions to obtain the displacement and stress in the frequency domain for an arbitrary FGM plate. The response of the plate to an incident pressure wave is obtained using the Fourier transform techniques. Results obtained by the present method are compared with an existing method using homogeneous layer elements. Numerical examples are presented to investigate stress waves in FGM plates. The relationship between the surface displacement response and the material property of quadratic FGM plates has been analytically obtained for the material characterization. A computational inverse technique is also presented for characterizing material property of an arbitrary FGM plate from the surface displacement response data, using present QLE method as forward solver and genetic algorithm as the inverse operator. This technique is utilized to reconstruct the material property of an actual SiC-C FGM.

  7. W–steel and W–WC–steel composites and FGMs produced by hot pressing

    Energy Technology Data Exchange (ETDEWEB)

    Matějíček, Jiří, E-mail: jmatejic@ipp.cas.cz [Institute of Plasma Physics, Za Slovankou 3, 18200 Praha (Czech Republic); Boldyryeva, Hanna; Brožek, Vlastimil [Institute of Plasma Physics, Za Slovankou 3, 18200 Praha (Czech Republic); Sachr, Pavel [Innovation Centre for Diagnostics and Application of Materials, Czech Technical University, Karlovo nám. 13, 12135 Praha (Czech Republic); Chráska, Tomáš [Institute of Plasma Physics, Za Slovankou 3, 18200 Praha (Czech Republic); Pala, Zdenek [Institute of Plasma Physics, Za Slovankou 3, 18200 Praha (Czech Republic); Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, Břehová 7, 11519 Praha (Czech Republic)

    2015-11-15

    Highlights: • Tungsten–steel and tungsten–WC–steel composites and FGMs were prepared by hot pressing. • Fully dense products were obtained. • Structure, thermal and mechanical properties were characterized. • Intermetallic phase formation was observed. - Abstract: Tungsten–steel composites and functionally graded materials (FGMs) are being developed for potential application in plasma facing components of fusion devices. Their role is to reduce thermal stresses at the interface between plasma facing tungsten armor and structural material. In this study, uniform composites and graded layers produced from tungsten and steel powders by hot pressing were investigated. Fully dense composites with uniform distribution and good bonding of the phases were formed. A thin layer of Fe{sub 2}W intermetallic phase was found at the interfaces. To avoid its formation, a third phase (tungsten carbide) was introduced between tungsten and steel. Structure, thermal and mechanical properties of both types of composites in the as-produced and annealed state were characterized.

  8. The Synthesis of Two- and Multilayer Functionally Graded Materials

    International Nuclear Information System (INIS)

    Varshalomidze, G.; Oniashvili, G.; Aslamazashvili, Z.; Zakharov, G.

    2008-01-01

    Two- and multilayer functionally graded materials (FGM) are produced via high-temperature self-propagated synthesis (SHS). Their 1 and 2 layers are produced using high-temperature thermo-mechanical treatment (HTTMT). One layer of the FGMs produced by SHS-compacting and tested with an original device is composed of one or two refractory compounds (borides, diborides, carbides), while the other plastic layer is composed of steels, metals or intermetallics. (author)

  9. Fabrication and characteristics of alumina-iron functionally graded materials

    DEFF Research Database (Denmark)

    He, Zeming; Ma, J.; Tan, G.E.B.

    2009-01-01

    In the present work, five-layered alumina–iron functionally graded materials (FGMs) were fabricated via a simple route of die pressing and pressureless sintering. The shrinkage differences among the layers in the FGM were minimized by particle size selection and processing control...... was achieved due to the toughening effect of iron and the crack deflection at the weak interfaces. This work provides a cost-effective manner to fabricate ceramic–metal gradient composites for armor applications....

  10. Overview of processing technologies for tungsten-steel composites and FGMs for fusion applications

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Nevrlá, Barbara; Vilémová, Monika; Boldyryeva, Hanna

    2015-01-01

    Roč. 60, č. 2 (2015), s. 267-273 ISSN 0029-5922. [Kudowa Summer School „Towards Fusion Energy“. Kudowa Zdrój, 09.06.2014-13.06.2014] R&D Projects: GA ČR(CZ) GAP108/12/1872 Institutional support: RVO:61389021 Keywords : plasma-facing components * functionally graded materials (FGMs), * tungsten * steel * plasma spraying * powder metallurgy Subject RIV: JK - Corrosion ; Surface Treatment of Materials Impact factor: 0.546, year: 2015 http://www.nukleonika.pl/#/?p=1222

  11. Free-edge stress analysis of functionally graded material layered biocomposite laminates.

    Science.gov (United States)

    Huang, Bin; Kim, Heung Soo

    2014-10-01

    A stress function based theory is proposed to obtain free-edge stress distributions for three-dimensional, orthotropic, linearly elastic rectangular biocomposite laminates with surface-bonded functionally graded materials (FGM). The assumed stress fields automatically satisfy the pointwise equilibrium equation, as well as traction-free and free edge boundary conditions. The complementary virtual work principle, followed by the general eigenvalue solution procedure, is used to obtain 3-D free edge stress states. A typical stacking sequence of composite laminate is used as numerical investigation with surface bonded FGMs. It is shown that with proper exponential factor of FGMs, the interlaminar stresses at the FGM layer interface can be reduced significantly, in return to prevent debonding of FGM layers. This approach can be useful in the design of functionally graded material layered biocomposite structures.

  12. Laser Rapid Manufacturing of Stainless Steel 316L/Inconel718 Functionally Graded Materials: Microstructure Evolution and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Dongjiang Wu

    2010-01-01

    Full Text Available Two patterns of functionally graded materials (FGMs were successfully fabricated whose compositions gradually varied from 100% stainless steel 316L to 100% Inconel718 superalloy using laser engineered net shaping process. The microstructure characterization, composition analysis, and microhardness along the graded direction were investigated. The comparison revealed the distinctions in solidification behavior, microstructure evolution of two patterns. In the end, the abrasive wear resistance of the material was investigated.

  13. Heat conduction analysis of multi-layered FGMs considering the finite heat wave speed

    International Nuclear Information System (INIS)

    Rahideh, H.; Malekzadeh, P.; Golbahar Haghighi, M.R.

    2012-01-01

    Highlights: ► Using a layerwise-incremental differential quadrature for heat transfer of FGMs. ► Superior accuracy with fewer degrees of freedom of the method with respect to FEM. ► Considering multi-layered functionally graded materials. ► Hyperbolic heat transfer analysis of thermal system with heat generation. ► Showing the effect of heat wave speed on thermal characteristic of the system. - Abstract: In this work, the heat conduction with finite wave heat speed of multi-layered domain made of functionally graded materials (FGMs) subjected to heat generation is simulated. For this purpose, the domain is divided into a set of mathematical layers, the number of which can be equal or greater than those of the physical layers. Then, in each mathematical layer, the non-Fourier heat transfer equations are employed. Since, the governing equations have variable coefficients due to FGM properties, as an efficient and accurate method the differential quadrature method (DQM) is adopted to discretize both spatial and temporal domains in each layer. This results in superior accuracy with fewer degrees of freedom than conventional finite element method (FEM). To verify this advantages through some comparison studies, a finite element solution are also obtained. After demonstrating the convergence and accuracy of the method, the effects of heat wave speed for two different set of boundary conditions on the temperature distribution and heat flux of the domain are studied.

  14. Development of W/Cu--functionally graded materials

    International Nuclear Information System (INIS)

    Pintsuk, G.; Bruenings, S.E.; Doering, J.-E.; Linke, J.; Smid, I.; Xue, L.

    2003-01-01

    Plasma facing components (PFCs) consist of a plasma facing and a heat sink material. These have to fulfil different functions that require different material properties, for example the coefficient of thermal expansion (CTE) of tungsten and copper. Joining of these materials (e.g. by brazing or HIPing) results in the formation of thermal-induced stresses at the interface. Functionally graded materials (FGMs), used as an interlayer, reduce these thermally induced stresses. Two different methods, laser sintering and plasma spraying, have been investigated as a means to produce W/Cu FGMs to be used in PFCs of next step confinement experiments. In addition to mixtures of tungsten and copper powders, 40 wt.% Cu-coated W powder was used to produce W/Cu composites with a content of either 25 or 60 vol.% Cu. The composite microstructure has been analyzed according to Cu content, particle distribution and layer structure. The difference in the behavior of powder mixtures and coated powder is outlined. A comparison of plasma sprayed to commercially produced Cu-infiltrated W samples is made and the results of thermomechanical and thermophysical testing are discussed with respect to different microstructures

  15. Transient temperature fields in functionally graded materials with different shapes under convective boundary conditions

    Science.gov (United States)

    Zhao, J.; Ai, X.; Li, Y. Z.

    2007-10-01

    This paper presents analyses of the transient temperature fields in an infinite plate, an infinite solid cylinder and a solid sphere made of functionally graded materials (FGMs) under convective boundary conditions. The composition and the thermo-physical properties of the infinite FGM plate, the infinite FGM solid cylinder and the FGM solid sphere are of planar symmetric, axially symmetric and spherically symmetric distributions, respectively. The analytical formulae of the one-dimensional transient temperature fields for the three FGM solids are obtained respectively by using the separation-of-variables method and the variable substitution method. Numerical results reveal that the transient temperature fields of the FGM components exhibit similar shape effect to that of homogeneous components. The present work provides valuable basis for the investigation of the thermal shock resistance of FGMs with various shapes.

  16. Functionally graded materials

    CERN Document Server

    Mahamood, Rasheedat Modupe

    2017-01-01

    This book presents the concept of functionally graded materials as well as their use and different fabrication processes. The authors describe the use of additive manufacturing technology for the production of very complex parts directly from the three dimension computer aided design of the part by adding material layer after layer. A case study is also presented in the book on the experimental analysis of functionally graded material using laser metal deposition process.

  17. Temperature/Stress Distributions in a Stress-Relief-Type Plate of Functionally Graded Materials under Thermal Shock

    Science.gov (United States)

    Awaji, Hideo; Takenaka, Hiromitsu; Honda, Sawao; Nishikawa, Tadahiro

    This paper presents a numerical technique for analyzing one-dimensional transient temperature and stress distributions in a stress-relief-type plate of functionally graded ceramic-metal based materials (FGMs), in relation to both the temperature-dependent thermal properties and continuous and gradual variation of the thermo-mechanical properties of the FGM. The FGM plate is assumed to be initially in steady state of temperature gradient, suffering high temperature at the ceramic side and low temperature at the metallic side associated with its in-service performance. The FGM plate is then rapidly cooled at the ceramic side of the plate by a cold medium. The transient temperature and related thermal stresses in the FGM plate are analyzed numerically for a model alumina-nickel FGM system. The proposed analytical technique for determining the temperature distribution is quite simple and widely applicable for various boundary conditions of FGMs, compared with methods recently proposed by other researchers. The optimum composition of FGMs is also discussed to reduce the thermal stresses in the FGM plate, relating to the function of the volume fraction of the metal across the thickness.

  18. Techniques for Mitigating Thermal Fatigue Degradation, Controlling Efficiency, and Extending Lifetime in a ZnO Thermoelectric Using Grain Size Gradient FGMs

    Science.gov (United States)

    Cramer, Corson L.; Li, Wenjie; Jin, Zhi-He; Wang, Jue; Ma, Kaka; Holland, Troy B.

    2018-01-01

    A functionally graded material (FGM) in terms of grain size gradation is fabricated using zinc oxide (ZnO) with spark plasma sintering and an additive manufacturing technique by diffusion bonding layers of material sintered at different temperatures to achieve a thermoelectric generator (TEG) material that can dissipate heat well and retain high energy conversion efficiency for longer-lasting and comparably efficient TEGs. This FGM is compared to a previously made FGM with continuous grain size gradation. Uniform and graded grain size conditions are modeled for thermoelectric output by using thermoelectric properties of the uniform grain size as well as the varying properties seen in the FGMs. The actual thermoelectric output of the samples is measured and compared to the simulations. The grain size has a large effect on the efficiency and efficiency range. The samples are thermally cycled with a fast heating rate to test the thermal stress robustness and degradation, and the resistance at the highest temperature is measured to indicate degradation from thermal stress. The measured efficiency after cycling shows that the FGMs survive longer lifetime than that with uniform small grains.

  19. Numerical modeling of wave propagation in functionally graded materials using time-domain spectral Chebyshev elements

    Science.gov (United States)

    Hedayatrasa, Saeid; Bui, Tinh Quoc; Zhang, Chuanzeng; Lim, Chee Wah

    2014-02-01

    Numerical modeling of the Lamb wave propagation in functionally graded materials (FGMs) by a two-dimensional time-domain spectral finite element method (SpFEM) is presented. The high-order Chebyshev polynomials as approximation functions are used in the present formulation, which provides the capability to take into account the through thickness variation of the material properties. The efficiency and accuracy of the present model with one and two layers of 5th order spectral elements in modeling wave propagation in FGM plates are analyzed. Different excitation frequencies in a wide range of 28-350 kHz are investigated, and the dispersion properties obtained by the present model are verified by reference results. The through thickness wave structure of two principal Lamb modes are extracted and analyzed by the symmetry and relative amplitude of the vertical and horizontal oscillations. The differences with respect to Lamb modes generated in homogeneous plates are explained. Zero-crossing and wavelet signal processing-spectrum decomposition procedures are implemented to obtain phase and group velocities and their dispersion properties. So it is attested how this approach can be practically employed for simulation, calibration and optimization of Lamb wave based nondestructive evaluation techniques for the FGMs. The capability of modeling stress wave propagation through the thickness of an FGM specimen subjected to impact load is also investigated, which shows that the present method is highly accurate as compared with other existing reference data.

  20. Nonlinear oscillations, bifurcations and chaos of functionally graded materials plate

    Science.gov (United States)

    Hao, Y. X.; Chen, L. H.; Zhang, W.; Lei, J. G.

    2008-05-01

    An analysis on the nonlinear dynamics of a simply supported functionally graded materials (FGMs) rectangular plate subjected to the transversal and in-plane excitations is presented in a thermal environment for the first time. Material properties are assumed to be temperature dependent. Based on Reddy's third-order plate theory, the nonlinear governing equations of motion for the FGM plates are derived using Hamilton's principle. Galerkin's method is utilized to discretize the governing partial equations to a two-degree-of-freedom nonlinear system including the quadratic and cubic nonlinear terms under combined parametric and external excitations. The resonant case considered here is 1:1 internal resonance and principal parametric resonance. The asymptotic perturbation method is utilized to obtain four-dimensional nonlinear averaged equation. The numerical method is used to find the nonlinear dynamic responses of the FGM rectangular plate. It was found that periodic, quasi-periodic solutions and chaotic motions exist for the FGM rectangular plates under certain conditions. It is believed that the forcing excitations f1 and f2 can change the form of motions for the FGM rectangular plate.

  1. Application of Functionally Graded Materials in Aircraft Structures

    Science.gov (United States)

    2005-03-01

    Matlab scripts). ABAQUS uses the Python object-oriented programming language to interface with the ABAQUS kernel (program) and allows for scripting that...and can be avoided with an advanced Python script which allows ABAQUS to query the Python script for material properties at the Gaussian points for...modeling FGMs using ABAQUS software. Conclusions drawn from FGM characterization are used to develop a patch to retrofit a cracked aircraft exhaust wash

  2. Fabrication, Characterization and Modeling of Functionally Graded Materials

    Science.gov (United States)

    Lee, Po-Hua

    In the past few decades, a number of theoretical and experimental studies for design, fabrication and performance analysis of solar panel systems (photovoltaic/thermal systems) have been documented. The existing literature shows that the use of solar energy provides a promising solution to alleviate the shortage of natural resources and the environmental pollution associated with electricity generation. A hybrid solar panel has been invented to integrate photovoltaic (PV) cells onto a substrate through a functionally graded material (FGM) with water tubes cast inside, through which water flow serves as both a heat sink and a solar heat collector. Due to the unique and graded material properties of FGMs, this novel design not only supplies efficient thermal harvest and electrical production, but also provides benefits such as structural integrity and material efficiency. In this work, a sedimentation method has been used to fabricate aluminum (Al) and high-density polyethylene (HDPE) FGMs. The size effect of aluminum powder on the material gradation along the depth direction is investigated. Aluminum powder or the mixture of Al and HDPE powder is thoroughly mixed and uniformly dispersed in ethanol and then subjected to sedimentation. During the sedimentation process, the concentration of Al and HDPE particles temporally and spatially changes in the depth direction due to the non-uniform motion of particles; this change further affects the effective viscosity of the suspension and thus changes the drag force of particles. A Stokes' law based model is developed to simulate the sedimentation process, demonstrate the effect of manufacturing parameters on sedimentation, and predict the graded microstructure of deposition in the depth direction. In order to improve the modeling for sedimentation behavior of particles, the Eshelby's equivalent inclusion method (EIM) is presented to determine the interaction between particles, which is not considered in a Stokes' law based

  3. Functionally Graded Material: An overview

    CSIR Research Space (South Africa)

    Mahamood, RM

    2012-07-01

    Full Text Available material is needed that will serve the purpose of the original bio-tissue. The ideal candidate for this application is functionally graded material. FGM has find wide range of application in dental [36] and orthopedic applications for teeth and bone... of Aluminium/Steel functionally graded material,? Materials Sciences and Applications, vol. 2, (2011), pp. 1708-1718. [15] F. Watari, A. Yokoyama, H. Matsuno, R. Miyao, M. Uo, T. Kawasaki, M. Omori, and T. Hirai, ?Fabrication of functionally graded implant...

  4. Mechanical analyses of pipeline repair and reinforcement with use of composite functionally graded materials; Analise mecanica de reforco de dutos submarinos com materiais compositos com gradacao funcional

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Marcos S.M. [Sondotecnica Engenharia de Solos S.A., Rio de Janeiro, RJ (Brazil); Roehl, Deane de Mesquita [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2008-07-01

    This work presents a methodology for design of stiffener sleeve constituted by functionally graded composite materials in offshore pipelines located in extreme-deep waters, where high mechanical resistance allied to an efficient system of thermal isolation is necessary, in view of the excellent thermomechanical behavior of composites. For the case of FGMs, due to continuous variation in its featuring, is necessary to employ an adapted model, based on a model typically adopted for conventional composites (Rule of Mixture), as the model idealized by Tamura, Tomato e Ozawa, the TTO model. In this report, the influence of geometric and materials parameters in mechanical behavior of pipelines under propagating collapse is analyzed. (author)

  5. Nonlinear dynamic response of a simply supported rectangular functionally graded material plate under the time-dependent thermal mechanical loads

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Y. X. [Beijing Information Science and Technology University, Beijing (China); Zhang, W. [Beijing University of Technology, Beijing (China); Yang, J. [RMIT University, Bundoora (Australia); Li, S. Y. [Ttianjin University of Technology and Education, Tianjin (China)

    2011-07-15

    An analysis on nonlinear dynamic characteristics of a simply supported functionally graded materials (FGMs) rectangular plate subjected to the transversal and in-plane excitations is presented in the time dependent thermal environment. Here we look the FGM Plates as isotropic materials which is assumed to be temperature dependent and graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents. The geometrical nonlinearity using Von Karman's assumption is introduced. The formulation also includes in-plane and rotary inertia effects. In the framework of Reddy's third-order shear deformation plate theory, the governing equations of motion for the FGM plate are derived by the Hamilton's principle. Then the equations of motion with two degree- of-freedom under combined the time-dependent thermomechanical loads can be obtained by using Galerkin's method. Using numerical method, the control equations are analyzed to obtain the response curves. Under certain conditions the periodic and chaotic motions of the FGM plate are found. It is found that because of the existence of the temperature which relate to the time the motions of the FGM plate show the great difference. A period motion can be changed into the chaotic motions which are affected by the time dependent temperature.

  6. Probabilistic Modeling of Graded Timber Material Properties

    DEFF Research Database (Denmark)

    Faber, M. H.; Köhler, J.; Sørensen, John Dalsgaard

    2004-01-01

    The probabilistic modeling of timber material characteristics is considered with special emphasis to the modeling of the effect of different quality control and selection procedures used as means for quality grading in the production line. It is shown how statistical models may be established on ...

  7. Thermomechanical Elastic Post-Buckling of Functionally Graded Materials Plate with Random System Properties

    Science.gov (United States)

    Jagtap, K. R.; Lal, Achchhe; Singh, B. N.

    2013-04-01

    This paper presents the stochastic post-buckling response of elastically supported FGM plate with random system properties subjected to uniform and nonuniform temperature change with temperature-dependent and -independent material properties. The FGMs plate is supported with two parameters of Pasternak foundation with Winkler cubic nonlinearity. The basic formulation is based on higher-order shear deformation theory (HSDT) with von-Karman nonlinearity using modified C0 continuity. A direct iterative-based nonlinear finite element method combined with first-order perturbation technique is used to compute the second-order statistics (mean and coefficient of variation) of post-buckling response of FGM plates.

  8. Fabrication of Al{sub 2}O{sub 3}-W Functionally Graded Materials by Slipcasting Method

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Tomoyuki; Sukenaga, Sohei; Saito, Noritaka; Nakashima, Kunihiko [Department of Materials Science and Engineering, Kyushu University, 744, Motooka, Nishiku, Fukuoka 819-0395 (Japan); Kagata, Hajime, E-mail: saito@zaiko.kyushu-u.ac.jp [Advanced Ceramic Section, TOTO Ltd., 2-1-1, Nakashima, Kokura, Kitakyushu, Fukuoka 802-8601 (Japan)

    2011-10-29

    We have successfully fabricated a functionally graded material (FGM) from tungsten and alumina powders by a slip-casting method. This FGM has applications as a sealing and conducting component for high-intensity discharge lamps (HiDLs) that have a translucent alumina envelope. Two types of W powder, with different oxidizing properties, were used as the raw powders for the Al{sub 2}O{sub 3}-W FGM. 'Oxidized W' was prepared by heat-treatment at 200 deg. C for 180 min in air. Alumina and each of the W powders were mixed in ultrapure water by ultrasonic stirring. The slurry was then cast into a cylindrical acrylic mold, which had a base of porous alumina, under controlled pressure. The green compacts were subsequently dried, and then sintered using a vacuum furnace at 1600 deg. C for a fixed time. The microstructures of the FGMs were observed by scanning electron microscopy (SEM) of the polished section. The Al{sub 2}O{sub 3}-W FGM with the 'oxidized W' powder resulted in a microscopic compositional gradient. However, the FGM with 'as-received W' showed no compositional gradient. This result was mainly attributed to the difference between the {zeta}-potentials of the W powders with the different oxidizing conditions; basically 'oxidized W' powder tends to disperse because of the larger {zeta}-potential of the oxide layer coated on the W powder core.

  9. Modeling Bamboo as a Functionally Graded Material

    Science.gov (United States)

    Silva, Emílio Carlos Nelli; Walters, Matthew C.; Paulino, Glaucio H.

    2008-02-01

    Natural fibers are promising for engineering applications due to their low cost. They are abundantly available in tropical and subtropical regions of the world, and they can be employed as construction materials. Among natural fibers, bamboo has been widely used for housing construction around the world. Bamboo is an optimized composite material which exploits the concept of Functionally Graded Material (FGM). Biological structures, such as bamboo, are composite materials that have complicated shapes and material distribution inside their domain, and thus the use of numerical methods such as the finite element method and multiscale methods such as homogenization, can help to further understanding of the mechanical behavior of these materials. The objective of this work is to explore techniques such as the finite element method and homogenization to investigate the structural behavior of bamboo. The finite element formulation uses graded finite elements to capture the varying material distribution through the bamboo wall. To observe bamboo behavior under applied loads, simulations are conducted considering a spatially-varying Young's modulus, an averaged Young's modulus, and orthotropic constitutive properties obtained from homogenization theory. The homogenization procedure uses effective, axisymmetric properties estimated from the spatially-varying bamboo composite. Three-dimensional models of bamboo cells were built and simulated under tension, torsion, and bending load cases.

  10. Optimum material gradient composition for the functionally graded ...

    African Journals Online (AJOL)

    user

    Functionally graded piezoelectric actuators can produce not only large displacements but also reduce the internal stress concentrations and consequently improve significantly the lifetime of piezoelectric actuators. Now, the functionally graded piezoelectric materials, as intelligent materials, have been used extensively in.

  11. Gradient effects on the fracture of inhomogeneous materials

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Terrence Lee [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    Functionally Graded Materials (FGMs) have a spatial variation in physical properties that can be tailored to meet the needs of a specific application and/or to minimize internal stresses arising from thermal and elastic mismatch. Modeling these materials as inhomogeneous continua allows assessment of the role of the gradient without requiring detailed knowledge of the microstructure. Motivated by the relative difficulty of obtaining analytical solutions to boundary value problems for FGMs, an accurate finite-element code is developed for obtaining numerical planar and axisymmetric linear thermoelastic solutions. In addition an approximate analytical technique for mapping homogeneous-modulus solutions to those for FGMs is assessed and classes of problems to which it applies accurately are identified. The fracture mechanics analysis of FGMs can be characterized by the classic stress intensities, KI and KII, but there has been scarce progress in understanding the role of the modulus gradient in determining fracture initiation and propagation. To address this question, a statistical fracture model is used to correlate near-tip stresses with brittle fracture initiation behavior. This describes the behavior of a material experiencing fracture initiation away from the crack tip. Widely dispersed zones of fracture initiation sites are expected. Finite-length kinks are analyzed to describe the crack path for continuous crack growth. For kink lengths much shorter than the gradient dimension, a parallel stress term describes the deviation of the kinking angle from that for homogeneous materials. For longer kinks there is a divergence of the kink angle predicted by the maximum energy release rate and the pure opening mode criteria.

  12. Design, Manufacturing and Characterization of Functionally Graded Flextensional Piezoelectric Actuators

    International Nuclear Information System (INIS)

    Amigo, R C R; Vatanabe, S L; Silva, E C N

    2013-01-01

    Previous works have been shown several advantages in using Functionally Graded Materials (FGMs) for the performance of flextensional devices, such as reduction of stress concentrations and gains in reliability. In this work, the FGM concept is explored in the design of graded devices by using the Topology Optimization Method (TOM), in order to determine optimal topologies and gradations of the coupled structures of piezoactuators. The graded pieces are manufactured by using the Spark Plasma Sintering (SPS) technique and are bonded to piezoelectric ceramics. The graded actuators are then tested by using a modular vibrometer system for measuring output displacements, in order to validate the numerical simulations. The technological path developed here represents the initial step toward the manufacturing of an integral piezoelectric device, constituted by piezoelectric and non-piezoelectric materials without bonding layers.

  13. Aeroelastic Tailoring of a Plate Wing with Functionally Graded Materials

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia; Jutte, Christine V.

    2014-01-01

    This work explores the use of functionally graded materials for the aeroelastic tailoring of a metallic cantilevered plate-like wing. Pareto trade-off curves between dynamic stability (flutter) and static aeroelastic stresses are obtained for a variety of grading strategies. A key comparison is between the effectiveness of material grading, geometric grading (i.e., plate thickness variations), and using both simultaneously. The introduction of material grading does, in some cases, improve the aeroelastic performance. This improvement, and the physical mechanism upon which it is based, depends on numerous factors: the two sets of metallic material parameters used for grading, the sweep of the plate, the aspect ratio of the plate, and whether the material is graded continuously or discretely.

  14. Geometrically non linear analysis of functionally graded material ...

    African Journals Online (AJOL)

    Geometrically non linear analysis of functionally graded material plates using higher order theory. ... International Journal of Engineering, Science and Technology. Journal Home ... The analysis of functionally graded material (FGM) plates with material variation parameter (n), boundary conditions, aspect ratios and side to ...

  15. Design and Fabrication of Aerospace-Grade Digital Composite Materials

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to advance design rules and fabrication approaches to create aerospace-grade structures from digital composite materials. Digital materials are...

  16. Thermomechanical Behavior of Functionally Graded Materials (FGM)

    National Research Council Canada - National Science Library

    Hudnut, Steven

    2001-01-01

    This final report is to document a summary of Ph.D. Student, Mr. Steven Hudnut who was supported by this ASSERT Grant, working on design of Piezo Actuators with Functionally Graded Microstructure (FGM). Mr...

  17. Micromechanical models for graded composite materials

    DEFF Research Database (Denmark)

    Reiter, T; Dvorak, G.J.; Tvergaard, Viggo

    1997-01-01

    Elastic response of selected plane-array models of graded composite microstructures is examined under both uniform and linearly varying boundary tractions and displacements, by means of detailed finite element studies of large domains containing up to several thousand inclusions. Models consisting...... of piecewise homogeneous layers with equivalent elastic properties estimated by Mori-Tanaka and self-consistent methods are also analysed under similar boundary conditions. Comparisons of the overall and local fields predicted by the discrete and homogenized models are made using a C/SiC composite system...... with very different Young's moduli of the phases, and relatively steep composition gradients. The conclusions reached from these comparisons suggest that in those parts of the graded microstructure which have a well-defined continuous matrix and discontinuous second phase, the overall properties and local...

  18. Interfacial adhesion of laser clad functionally graded materials

    NARCIS (Netherlands)

    Ocelik, V.; Pei, Y.T.; de Hosson, J.T.M.; Popoola, O; Dahotre, NB; Midea, SJ; Kopech, HM

    2003-01-01

    Two functionally graded coatings were prepared by different laser surface engineering techniques. Laser cladding of AlSi40 powder leads to the formation of functionally graded material (FGM) coating on AI-Si cast alloy substrate. Mapping of strain fields near the laser clad track using the digital

  19. Highway-rail grade crossing surface material performance.

    Science.gov (United States)

    2014-04-01

    Highway-Railroad grade crossings are an integral part of the transportation system, allowing the : two modes to operate in the same areas. Performance of the surface material at grade : crossings has been an ongoing issue. This study reviewed the lit...

  20. Development of functionally graded materials by ultrasonic consolidation

    CSIR Research Space (South Africa)

    Kumar, S

    2010-08-01

    Full Text Available Development of Functionally Graded Materials (FGM) using Ultrasonic Consolidation (UC) needs the joining of different metallic foils together. The present work deals with the joining of stainless steel, Al and Cufoils. Optimum experimental...

  1. Thermal shock analysis of functionally graded materials by micromechanical model

    International Nuclear Information System (INIS)

    Ueda, Sei

    2002-01-01

    The transient thermoelastic behavior of the functionally graded plate due to a thermal shock with temperature dependent properties is studied in this paper. The development of a micromechanical model for the functionally graded materials is presented and its application to thermoelastic analysis is discussed for the case of the W-Cu functionally graded material for the International Thermonuclear Experimental Reactor divertor plate. The divertor plate is made of a graded layer bonded between a homogeneous substrate and a homogeneous coating, and it is subjected to a cycle of heating and cooling on the coating surface of the material. The thermal and elastic properties of the material are dependent on the temperature and the position. Numerical calculations are carried out, and the results for the transient temperature and thermal stress distributions are displayed graphically. (author)

  2. Ceramic/polymer functionally graded material (FGM) lightweight armor system

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.; McClellan, K.J.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials.

  3. Chaotic dynamics of size dependent Timoshenko beams with functionally graded properties along their thickness

    Science.gov (United States)

    Awrejcewicz, J.; Krysko, A. V.; Pavlov, S. P.; Zhigalov, M. V.; Krysko, V. A.

    2017-09-01

    Chaotic dynamics of microbeams made of functionally graded materials (FGMs) is investigated in this paper based on the modified couple stress theory and von Kármán geometric nonlinearity. We assume that the beam properties are graded along the thickness direction. The influence of size-dependent and functionally graded coefficients on the vibration characteristics, scenarios of transition from regular to chaotic vibrations as well as a series of static problems with an emphasis put on the load-deflection behavior are studied. Our theoretical/numerical analysis is supported by methods of nonlinear dynamics and the qualitative theory of differential equations supplemented by Fourier and wavelet spectra, phase portraits, and Lyapunov exponents spectra estimated by different algorithms, including Wolf's, Rosenstein's, Kantz's, and neural networks. We have also detected and numerically validated a general scenario governing transition into chaotic vibrations, which follows the classical Ruelle-Takens-Newhouse scenario for the considered values of the size-dependent and grading parameters.

  4. Direct-write graded index materials realized in protein hydrogels

    Science.gov (United States)

    Kaehr, Bryan; Scrymgeour, David A.

    2016-09-01

    The ability to create optical materials with arbitrary index distributions would prove transformative for optics design and applications. However, current fabrication techniques for graded index (GRIN) materials rely on diffusion profiles and therefore are unable to realize arbitrary distribution GRIN design. Here, we demonstrate the laser direct writing of graded index structures in protein-based hydrogels using multiphoton lithography. We show index changes spanning a range of 10-2, which is comparable with laser densified glass and polymer systems. Further, we demonstrate the conversion of these written density variation structures into SiO2, opening up the possibility of transforming GRIN hydrogels to a wide range of material systems.

  5. Optimum material gradient composition for the functionally graded ...

    African Journals Online (AJOL)

    This study investigates the relation between the material gradient properties and the optimum sensing/actuation design of the functionally graded piezoelectric beams. Three-dimensional (3D) finite element analysis has been employed for the prediction of an optimum composition profile in these types of sensors and ...

  6. Geometrically non linear analysis of functionally graded material ...

    African Journals Online (AJOL)

    user

    when compared to the other engineering materials (Akhavan and Hamed, 2010). However, FGM plates under mechanical loading may undergo elastic instability. Hence, the non-linear behavior of functionally graded plates has to be understood for their optimum design. Reddy (2000) proposed the theoretical formulation ...

  7. Functionally graded materials produced with high power lasers

    NARCIS (Netherlands)

    De Hosson, J. T. M.; Ocelik, V.; Chandra, T; Torralba, JM; Sakai, T

    2003-01-01

    In this keynote paper two examples will be present of functionally graded materials produced with high power Nd:YAG lasers. In particular the conditions for a successful Laser Melt Injection (LMI) of SiC and WC particles into the melt pool of A18Si and Ti6Al4V alloys are presented. The formation of

  8. IFR starts to burn up weapons-grade material

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    With funding from different parts of the federal government, the Integral Fast Reactor (IFR) project has survived into fiscal year 1994 and is now embarking on a demonstration of how this type of liquid-metal-cooled reactor (LMR) can be used to burn fuel derived from weapons-grade plutonium. This month, an assembly made from weapons-grade material is to be loaded into Experimental Breeder Reactor-II in Idaho, which is serving as the prototype for the IFR concept. Although FY 1994 work is being funded by the DOE, this particular examination of plutonium burnup is backed by the Department of Defense

  9. Nanoadhesion of a Power-Law Graded Elastic Material

    International Nuclear Information System (INIS)

    Shao-Hua, Chen; Pei-Jian, Chen

    2010-01-01

    The Dugdale—Barenblatt model is used to analyze the adhesion of graded elastic materials at the nanoscale with Young's modulus E varying with depth z according to a power law E = E 0 (z/c 0 ) (0 0 is a referenced Young's modulus, k is the gradient exponent and c 0 is a characteristic length describing the variation rate of Young's modulus. We show that, when the size of a rigid punch becomes smaller than a critical length, the adhesive interface between the punch and the graded material detaches due to rupture with uniform stresses, rather than by crack propagation with stress concentration. The critical length can be reduced to the one for isotropic elastic materials only if the gradient exponent k vanishes

  10. Nanoadhesion of a Power-Law Graded Elastic Material

    Science.gov (United States)

    Chen, Shao-Hua; Chen, Pei-Jian

    2010-10-01

    The Dugdale—Barenblatt model is used to analyze the adhesion of graded elastic materials at the nanoscale with Young's modulus E varying with depth z according to a power law E = E0(z/c0) (0 < k < 1) while Poisson's ratio v remains a constant, where E0 is a referenced Young's modulus, k is the gradient exponent and c0 is a characteristic length describing the variation rate of Young's modulus. We show that, when the size of a rigid punch becomes smaller than a critical length, the adhesive interface between the punch and the graded material detaches due to rupture with uniform stresses, rather than by crack propagation with stress concentration. The critical length can be reduced to the one for isotropic elastic materials only if the gradient exponent k vanishes.

  11. Approximation of functionally graded plates with non-conforming finite elements

    Science.gov (United States)

    Chinosi, Claudia; Della Croce, Lucia

    2007-12-01

    In this paper rectangular plates made of functionally graded materials (FGMs) are studied. A two-constituent material distribution through the thickness is considered, varying with a simple power rule of mixture. The equations governing the FGM plates are determined using a variational formulation arising from the Reissner-Mindlin theory. To approximate the problem a simple locking-free Discontinuous Galerkin finite element of non-conforming type is used, choosing a piecewise linear non-conforming approximation for both rotations and transversal displacement. Several numerical simulations are carried out in order to show the capability of the proposed element to capture the properties of plates of various gradings, subjected to thermo-mechanical loads.

  12. Love wave propagation in functionally graded piezoelectric material layer.

    Science.gov (United States)

    Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

    2007-03-01

    An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices.

  13. Experimental Tape Casting of Adjacently Graded Materials for Magnetic Refrigeration

    DEFF Research Database (Denmark)

    Bulatova, Regina

    Functional graded materials are extensively applied in many innovative technologies, e.g. solid oxide fuel cells, solar cells, membranes, piezoactuators, capacitors, and thermoelectric systems. The synergy of advantageous combinations of composites with different composition and/or microstructure...... encompass modification of the entire tape caster into a multi chamber unit, establishment of the optimal operating parameters such as casting gap, speed, and slurry level in the tape caster reservoir, and elucidation of the impact of chamber partition design on the quality of the final tape. The second...

  14. Fatigue crack growth simulations of interfacial cracks in bi-layered FGMs using XFEM

    Science.gov (United States)

    Bhattacharya, S.; Singh, I. V.; Mishra, B. K.; Bui, T. Q.

    2013-10-01

    An investigation of fatigue crack growth of interfacial cracks in bi-layered materials using the extended finite element method is presented. The bi-material consists of two layers of dissimilar materials. The bottom layer is made of aluminium alloy while the upper one is made of functionally graded material (FGM). The FGM layer consists of 100 % aluminium alloy on the left side and 100 % ceramic (alumina) on the right side. The gradation in material property of the FGM layer is assumed to be exponential from the alloy side to the ceramic side. The domain based interaction integral approach is extended to obtain the stress intensity factors for an interfacial crack under thermo-mechanical load. The edge and centre cracks are taken at the interface of bi-layered material. The fatigue life of the interface crack plate is obtained using the Paris law of fatigue crack growth under cyclic mode-I, mixed-mode and thermal loads. This study reveals that the crack propagates into the FGM layer under all types of loads.

  15. Modelling of functionally graded materials by numerical homogenization

    Energy Technology Data Exchange (ETDEWEB)

    Schmauder, S.; Weber, U. [Stuttgart Univ. (Germany). Staatliche Materialpruefungsanstalt

    2001-03-01

    In this contribution, the mechanical behaviour of different ZrO{sub 2}/NiCr 80 20 compositions is analysed and compared with experimental findings. The microwave-sintered material is found to possess a slightly dominant ceramic matrix for intermediate volume fractions. Its thermal expansion coefficient deviates from the rule of mixture. The modulus and the stress strain behaviour can be simulated by a numerical homogenization procedure, and the influence of residual stresses is found to be negligible. A newly introduced parameter (matricity) describes the mutual circumvention of the phases and is found to strongly control the stress level of the composite, globally as well as locally. Finally, a graded component and a metal/ceramic bi-material are compared for thermal as well as mechanical loading. (orig.)

  16. Stress concentration in a finite functionally graded material plate

    Science.gov (United States)

    Yang, QuanQuan; Gao, CunFa; Chen, WenTao

    2012-07-01

    This paper is to study the two-dimensional stress distribution of a finite functionally graded material (FGM) plate with a circular hole under arbitrary constant loads. Using the method of piece-wise homogeneous layers, the stress analysis of the finite FGM plate having radial arbitrary elastic properties is made based on the complex variable method combined with the least square boundary collocation technique. Numerical results of stress distribution around the hole are then presented for different loading conditions, different material properties and different plate sizes, respectively. It is shown that the stress concentration in the finite plate is generally enhanced compared with the case of an infinite plate, but it can be significantly reduced by choosing proper change ways of the radial elastic modulus.

  17. Overview of processing technologies for tungsten-steel composites and FGMs for fusion applications

    Directory of Open Access Journals (Sweden)

    Matějíček Jiří

    2015-06-01

    Full Text Available Tungsten is a prime candidate material for the plasma-facing components in future fusion devices, e.g. ITER and DEMO. Because of the harsh and complex loading conditions and the differences in material properties, joining of the tungsten armor to the underlying construction and/or cooling parts is a complicated issue. To alleviate the thermal stresses at the joint, a sharp interface may be replaced by a gradual one with a smoothly varying composition. In this paper, several techniques for the formation of tungsten-steel composites and graded layers are reviewed. These include plasma spraying, laser cladding, hot pressing and spark plasma sintering. Structure, composition and selected thermal and mechanical properties of representative layers produced by each of these techniques are presented. A summary of advantages and disadvantages of the techniques and an assessment of their suitability for the production of plasma-facing components is provided.

  18. The Influence of Al2O3 Powder Morphology on the Properties of Cu-Al2O3 Composites Designed for Functionally Graded Materials (FGM)

    Science.gov (United States)

    Strojny-Nędza, Agata; Pietrzak, Katarzyna; Węglewski, Witold

    2016-08-01

    In order to meet the requirements of an increased efficiency applying to modern devices and in more general terms science and technology, it is necessary to develop new materials. Combining various types of materials (such as metals and ceramics) and developing composite materials seem to be suitable solutions. One of the most interesting materials includes Cu-Al2O3 composite and gradient materials (FGMs). Due to their potential properties, copper-alumina composites could be used in aerospace industry as rocket thrusters and components in aircraft engines. The main challenge posed by copper matrix composites reinforced by aluminum oxide particles is obtaining the uniform structure with no residual porosity (existing within the area of the ceramic phase). In the present paper, Cu-Al2O3 composites (also in a gradient form) with 1, 3, and 5 vol.% of aluminum oxide were fabricated by the hot pressing and spark plasma sintering methods. Two forms of aluminum oxide (αAl2O3 powder and electrocorundum) were used as a reinforcement. Microstructural investigations revealed that near fully dense materials with low porosity and a clear interface between the metal matrix and ceramics were obtained in the case of the SPS method. In this paper, the properties (mechanical, thermal, and tribological) of composite materials were also collected and compared. Technological tests were preceded by finite element method analyses of thermal stresses generated in the gradient structure, and additionally, the role of porosity in the formation process of composite properties was modeled. Based on the said modeling, technological conditions for obtaining FGMs were proposed.

  19. Bending analysis of different material distributions of functionally graded beam

    Science.gov (United States)

    Aldousari, S. M.

    2017-04-01

    Most analyses of functional graded materials (FGM) focusing on power law distribution, which presents stress concentration at the interface when material properties change rapidly. The objective of the current paper is to develop two symmetric and anti-symmetric functions and compare their effects on the static deflection and bending stresses with classical power-law distribution. The proposed distributions are a symmetric power-law and a sigmoid function which is anti-symmetric. To homogenized micromechanical properties of FGM, the effective material properties are derived on the basis of Voigt model. Kinematic relation of Euler-Bernoulli beam is assumed and virtual work is proposed to derive the equilibrium equations. A finite element model is proposed to form stiffness matrix and force vector and then solve the problem numerically. Proposed model has been validated. Numerical results presents the effect of power exponent, and elasticity ratios on a static deflection and stresses of FG beams. The most significant finding is that, the symmetric power function is more reliable and can considerably reduce the stress than the other two functions. However, the sigmoid function distribution represents the highest stress.

  20. Japanese Language and Culture: 9-Year Program Classroom Assessment Materials, Grade 4

    Science.gov (United States)

    Alberta Education, 2008

    2008-01-01

    This document is designed to provide assessment materials for specific Grade 4 outcomes in the Japanese Language and Culture Nine-year Program, Grades 4-5-6. The assessment materials are designed for the beginner level in the context of teaching for communicative competence. Grade 4 learning outcomes from the Japanese Language and Culture…

  1. Sonic Fatigue Testing of a Functionally Graded Ti/TiB Material

    Science.gov (United States)

    2008-01-01

    5 Figure 4. Backscattered SEM Images Showing the Layers of the 3-mm FGM plate .................... 7 Figure 5. Higher...TiB. The powders were sintered at 1578°K under a pressure of 13.8 MPa. The FGMs were fabricated as square plates , nominally 150 mm on a side by 3 mm...1. One of the FGM specimens, 996-1.1, broke during machining and was replaced by a specimen from another plate , 1011-1. 3 Figure 1

  2. Resistivity measurements on the neutron irradiated detector grade silicon materials

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng

    1993-11-01

    Resistivity measurements under the condition of no or low electrical field (electrical neutral bulk or ENB condition) have been made on various device configurations on detector grade silicon materials after neutron irradiation. Results of the measurements have shown that the ENB resistivity increases with neutron fluence ({Phi}{sub n}) at low {phi}{sub n} (<10{sup 13} n/cm{sup 2}) and saturates at a value between 300 and 400 k{Omega}-cm at {phi}{sub n} {approximately}10{sup 13} n/cm{sup 2}. Meanwhile, the effective doping concentration N{sub eff} in the space charge region (SCR) obtained from the C-V measurements of fully depleted p{sup +}/n silicon junction detectors has been found to increase nearly linearly with {phi}{sub n} at high fluences ({phi}{sub n} > 10{sup 13} n/cm{sup 2}). The experimental results are explained by the deep levels crossing the Fermi level in the SCR and near perfect compensation in the ENB by all deep levels, resulting in N{sub eff} (SCR) {ne} n or p (free carrier concentrations in the ENB).

  3. Bombs grade 'spent' nuclear material removed from Uzbekistan

    International Nuclear Information System (INIS)

    2006-01-01

    Full text: Spent nuclear fuel containing enough uranium to produce 2.5 nuclear weapons has been safely returned to Russia from Uzbekistan in a classified mission completed on 19 April 2006. It is the first time that fuel used in a nuclear research reactor - referred to as 'spent' - has been repatriated to Russia since the break-up of the Soviet Union. Under tight security, 63 kilograms of spent highly enriched uranium (HEU) was transported to Mayak in Russia, in four separate shipments. IAEA safeguards inspectors monitored and verified the packing of the fuel for transport over the course of 16 days. The secret operation, six years in the planning, was a joint undertaking of the IAEA, the United States, Uzbekistan, Russia and Kazakhstan as part of the Global Threat Reduction Initiative (GTRI). The aim of the GTRI is to identify, secure and recover high-risk vulnerable nuclear and radiological materials around the world. 'There was particular concern about the Uzbek spent fuel given its significant quantity and that it was no longer 'self protecting', 'the IAEA's Crosscutting Co-ordinator for Research Reactors, Mr. Pablo Adelfang, said. 'This means that the fuel has lost its high radioactivity. In other words, it would no longer injure anyone who handled it and would not deter potential thieves,' Mr. Adelfang said. 'The shipment is an important step to reduce stockpiles of high-risk, vulnerable nuclear materials. Russia, the US, Uzbekistan and Kazakhstan should be applauded for their successful cooperation. It will contribute to the security of both Uzbekistan and the international community,' he added. In Russia, the fuel will be processed so that it can not be used for atomic bombs. Russia originally supplied the nuclear fuel to Uzbekistan for use in its 10 megawatt research reactor. Located at the Institute of Nuclear Physics of Uzbekistan, 30 km from Tashkent, the reactor is currently used for research and to produce isotopes for medical purposes. The IAEA is

  4. Graded territories: Towards the design, specification and simulation of materially graded bending active structures

    DEFF Research Database (Denmark)

    Nicholas, Paul; Tamke, Martin; Ramsgaard Thomsen, Mette

    2012-01-01

    these structures, the property of bending is activated and varied through bespoke material means so as to match a desired form. Within the architectural design process, formal control depends upon design approaches for material specification and simulation that consider behavior at the level of the material...... element as well as the structure. We describe an evolving approach to material specification and simulation, and highlight the digital and material considerations that frame the process.......The ability to make materials with bespoke behavior affords new perspectives on incorporating material properties within the design process not available through natural materials. This paper reports the design and assembly of two bending-active, fibre-reinforced composite structures. Within...

  5. Determination and modeling of residual stress in functionally graded WC-Co

    Science.gov (United States)

    Tahvilian, Leila

    Gradual variations in composition and/or structure through the volume of functionally graded materials (FGMs) generally result in corresponding continuous spatial variations in mechanical/physical properties, and often in significant residual stresses that develop during processing. Due to inhomogeneous properties in these materials, residual stress measurement in FGMs can be a very challenging problem. In this study, residual stresses in functionally graded cemented tungsten carbide (FG-WC-Co) were investigated by numerical, analytical and experimental approaches by means of a layer removal technique. The numerical method consisted of finite element analysis (FEA) modeling for the FGM plate, in order to calculate residual stress distribution over the volume and to develop a method for predicting residual stress levels in closely related materials. The analytical procedure embodied a mathematical approach to determine residual stress distributions, and analytically determined values are compared with those obtained from FEA modeling and experimental results. The experimental approach consisted of fabricating and heat treating FG-WC-Co flat samples, then measuring strain changes by strain gauge after each sequential layer removal from the opposite side of the specimen from the graded region. Good agreement was found between analytical, numerical and experimental results. Furthermore, thermal residual stress distribution in FG-WC-Co hollow cylinder was examined with an emphasis on the effects of key variables, the gradient profile and the gradient thickness, on the magnitude and distribution of the stress field. An analytical direct solution based on solving the governing equations of a cylinder composed of a uniform inner core and a functionally graded outer shell was developed. The cylindrical compound was considered as two separate elements: homogeneous cylinder and functionally graded shell. Material properties, such as the elastic modulus and the coefficient of

  6. [Brief introduction of research methods of commodity specification and grade of Chinese medicinal materials].

    Science.gov (United States)

    Zhao, Hua-ye; Yan, Pei-pei; Yang, Wen-hua; Li, Chao-feng; Qi, Shu-ya; Li, Yan-qi; Cao, Jun-ling

    2015-02-01

    The commodity specification and grade of Chinese medicinal materials is a measure of the quality of traditional Chinese medicines (TCMs), which directly impacts on the safety and effectiveness of clinical medicines. It is an urgent problem to establish a set of standards which can both interpret the scientific connotation of the commodity specification and grade of Chinese medicinal materials and play a significant role on clinical medicines as well as markets. This paper reviews the research methods of the commodity specification and grade of Chinese medicinal materials such as sensory evaluation, chemical assessment, biological evaluation, and cited the applications of various methods for the classification of TCMs. It provides technical support for establishing standards of the commodity specification and grade of Chinese medicinal materials, and also constructs scientific basis for clinical rational drug use.

  7. An evaluation of the stress intensity factor in functionally graded materials

    Czech Academy of Sciences Publication Activity Database

    Ševčík, Martin; Hutař, Pavel; Náhlík, Luboš; Knésl, Zdeněk

    2009-01-01

    Roč. 3, č. 2 (2009), s. 401-410 ISSN 1802-680X R&D Projects: GA ČR GD106/09/H035; GA ČR GC101/09/J027 Institutional research plan: CEZ:AV0Z20410507 Keywords : functionally graded material * power -law material change Subject RIV: JL - Materials Fatigue, Friction Mechanics

  8. Material Design of Functionally Graded Plates with the Function of Electromagnetic Noise Suppression

    Science.gov (United States)

    Sugano, Yoshihiro; Takahashi, Satoshi

    The development of materials to suppress electromagnetic noise is in demand. In this paper, we present a method for the material design of functionally graded material (FGM) plates with the function of electromagnetic noise suppression. The FGM plates are considered to be multilayered plates in which the material properties are homogeneous inside each layer. Therefore, the approximate analytical solutions of electromagnetic fields in the FGM plates subject to electromagnetic noise are derived. The expressions for electromagnetic noise suppression are then obtained based on the above analytical solutions. Numerical calculations are carried out for epoxy resin/titanium oxide FGM plates with graded composition distribution expressed in the form of a power function. The effects of graded composition and plate thickness on the electromagnetic noise suppression are quantitatively evaluated, and the material design suitable for the suppression of electromagnetic noise is discussed.

  9. Optimal Experiment Design for Thermal Characterization of Functionally Graded Materials

    Science.gov (United States)

    Cole, Kevin D.

    2003-01-01

    The purpose of the project was to investigate methods to accurately verify that designed , materials meet thermal specifications. The project involved heat transfer calculations and optimization studies, and no laboratory experiments were performed. One part of the research involved study of materials in which conduction heat transfer predominates. Results include techniques to choose among several experimental designs, and protocols for determining the optimum experimental conditions for determination of thermal properties. Metal foam materials were also studied in which both conduction and radiation heat transfer are present. Results of this work include procedures to optimize the design of experiments to accurately measure both conductive and radiative thermal properties. Detailed results in the form of three journal papers have been appended to this report.

  10. Technical criteria for terminating or reducing domestic safeguards on low-grade special nuclear material

    International Nuclear Information System (INIS)

    Crawford, D.W.

    1996-01-01

    A graded table for terminating or reducing domestic safeguards has been developed for use by programs and facilities within the Department of Energy in decisions regarding the need for or levels of protection of low-grade nuclear materials. Contained in this table are technical criteria which can allow for complete removal of safeguards over many special nuclear material forms and concentrations of typical low-grade materials either currently located at generating or processing sites and materials which may arise from processing operations related to stabilization and disposition activities. In addition, these criteria include higher concentration levels which may warrant maintaining some level of (albeit reduced) security on low-grade materials while allowing reductions in materials control and accountability requirements. These reductions can range from complete removal of these materials from materials control and accountability requirements such as measurements, physical inventories and recordkeeping, to deferring these measurements and physical inventories until a time that either the material is removed from the site or resubmitted for processing. It is important to note that other conditions contained in current Departmental safeguards and security policy be met prior to safeguards termination or reduction

  11. Three-Dimensional Finite Element Modeling of Thermomechanical Problems in Functionally Graded Hydroxyapatite/Titanium Plate

    Directory of Open Access Journals (Sweden)

    S. N. S. Jamaludin

    2014-01-01

    Full Text Available The composition of hydroxyapatite (HA as the ceramic phase and titanium (Ti as the metallic phase in HA/Ti functionally graded materials (FGMs shows an excellent combination of high biocompatibility and high mechanical properties in a structure. Because the gradation of these properties is one of the factors that affects the response of the functionally graded (FG plates, this paper is presented to show the domination of the grading parameter on the displacement and stress distribution of the plates. A three-dimensional (3D thermomechanical model of a 20-node brick quadratic element is used in the simulation of the thermoelastic behaviors of HA/Ti FG plates subjected to constant and functional thermal, mechanical, and thermomechanical loadings. The convergence properties of the present results are examined thoroughly in order to assess the accuracy of the theory applied and to compare them with the established research results. Instead of the grading parameter, this study reveals that the loading field distribution can be another factor that reflects the thermoelastic properties of the HA/Ti FG plates. The FG structure is found to be able to withstand the thermal stresses while preserving the high toughness properties and thus shows its ability to operate at high temperature.

  12. W–steel and W–WC–steel composites and FGMs produced by hot pressing

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Boldyryeva, Hanna; Brožek, Vlastimil; Sachr, P.; Chráska, Tomáš; Pala, Zdeněk

    2015-01-01

    Roč. 100, November (2015), s. 364-370 ISSN 0920-3796 R&D Projects: GA ČR(CZ) GAP108/12/1872 EU Projects: European Commission(DE) WP11-MAT-WWALLOY Institutional support: RVO:61389021 Keywords : FGM * Composite * Tungsten * Steel * Fusion reactor material Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.301, year: 2015 http://www.sciencedirect.com/science/article/pii/S0920379615302106

  13. Prediction of the adhesive behavior of bio-inspired functionally graded materials against rough surfaces

    Directory of Open Access Journals (Sweden)

    Chen Peijian

    2014-06-01

    Full Text Available Roughness effect and adhesion properties are important characteristics to be accessed in the development of functionally graded materials for biological and biomimetic applications, particularly for the hierarchical composition in biomimetic gecko robot. A multi-asperities adhesion model to predict the adhesive forces is presented in this work. The effect of surface roughness and graded material properties, which significantly alter the adhesive strength between contact bodies, can be simultaneously considered in the generalized model. It is found that proper interfacial strength can be controlled by adjusting surface roughness σ / R, graded exponent k and material parameter E*R / Δγ. The results should be helpful in the design of new biomimetic materials and useful in application of micro functional instruments.

  14. Functionally Graded Materials by Laser Metal Deposition (PREPRINT)

    Science.gov (United States)

    2010-03-01

    composition of Fe-82 wt% V (powder-1) and Inconel - 625 (powder-2) powders are listed in Table 1. The substrate materials used for the experiment were cold...like laser power, travel speed and powder feed rate is yet to be determined to obtain a successful FGM. Inconel - 625 deposits showed macro-cracks...Composition (wt%) Powder-1: Fe-82 wt% V V (82), Al (0.68), Si (0.9), C (0.07), S (0.01), P (0.02), Fe (18) Powder-2: Inconel - 625 Ni (58), Cr (20-23

  15. Crack propagation in functionally graded materials and structures; Risswachstum in funktional gradierten Materialien und Strukturen

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, Britta

    2014-07-01

    Components with graded fracture-mechanical properties show a fundamentally different crack propagation behaviour than do homogeneous, isotropic structures. This becomes especially evident in investigations on the influence of fracture-mechanical material grading on the stage of steady fatigue crack propagation and on crack propagation speed da/dN. Theoretical findings based on the so-called TSSR concept, which was developed as part of this dissertation, indicate that it can have either positive or negative effects on crack propagation behaviour, depending on various material characteristics and grading constellations. The dissertation reports on experiments for validating theoretical statements on the influence of different structural conditions on crack propagation behaviour. These statements were largely found to be correct. The study thus contributes to the prediction of crack propagation in fracture-mechanically graded components and structures subject to static or cyclical stress.

  16. Study on the Reflection Spectra of One Dimensional Plasma Photonic Crystals Having Exponentially Graded Materials

    International Nuclear Information System (INIS)

    Prasad, S.; Singh, Vivek; Singh, A. K.

    2013-01-01

    The transfer matrix method is used to study the effect of the permittivity profile on the reflectivity of a one dimensional plasma photonic crystal having exponentially graded material. The analysis shows that the proposed structure works as a perfect mirror within a certain frequency range. These frequency ranges can be completely controlled by the permittivity profile of a graded dielectric layer. As expected we observed that these frequency ranges are also controlled by plasma parameters. (plasma technology)

  17. Deflection control of functionally graded material beams with bonded piezoelectric sensors and actuators

    International Nuclear Information System (INIS)

    Gharib, Ahmad; Salehi, Manouchehr; Fazeli, Saeed

    2008-01-01

    An analytical solution is developed for analysis of functionally graded material (FGM) beams containing two layers of piezoelectric material, used as sensor and actuator. The properties of FGM layer are functionally graded in the thickness direction according to the volume fraction power law distribution. The equations of motion are derived by using Hamilton's principle, based on the first-order shear deformation theory. By using a displacement potential function, and assumption of harmonic vibration, the equations of motion have been solved analytically. Finally, the effects of FGM constituent volume fraction in the peak responses for various volume fraction indexes have been graphically illustrated

  18. Material and Thickness Grading for Aeroelastic Tailoring of the Common Research Model Wing Box

    Science.gov (United States)

    Stanford, Bret K.; Jutte, Christine V.

    2014-01-01

    This work quantifies the potential aeroelastic benefits of tailoring a full-scale wing box structure using tailored thickness distributions, material distributions, or both simultaneously. These tailoring schemes are considered for the wing skins, the spars, and the ribs. Material grading utilizes a spatially-continuous blend of two metals: Al and Al+SiC. Thicknesses and material fraction variables are specified at the 4 corners of the wing box, and a bilinear interpolation is used to compute these parameters for the interior of the planform. Pareto fronts detailing the conflict between static aeroelastic stresses and dynamic flutter boundaries are computed with a genetic algorithm. In some cases, a true material grading is found to be superior to a single-material structure.

  19. Microstructure and properties of aluminium-aluminium oxide graded composite materials

    Science.gov (United States)

    Kamaruzaman, F. F.; Nuruzzaman, D. M.; Ismail, N. M.; Hamedon, Z.; Iqbal, A. K. M. A.; Azhari, A.

    2018-03-01

    In this research works, four-layered aluminium-aluminium oxide (Al-Al2O3) graded composite materials were fabricated using powder metallurgy (PM) method. In processing, metal-ceramic graded composite materials of 0%, 10%, 20% and 30% weight percentage of ceramic concentration were prepared under 30 ton compaction load using a cylindrical die-punch set made of steel. After that, two-step pressureless sintering was carried out at sintering temperature and time 600°C and 3 hours respectively. It was observed that the sintered cylindrical specimens of 30 mm diameter were prepared successfully. The graded composite specimens were analysed and the properties such as density, microstructure and hardness were measured. It was found that after sintering process, the diameter of the graded cylindrical structure was decreased. Using both Archimedes method and rule of mixture (ROM), he density of structure was measured. The obtained results revealed that the microvickers hardness was increased as the ceramic component increases in the graded layer. Moreover, it was observed that the interface of the graded structure is clearly distinguished within the multilayer stack and the ceramic particles are almost uniformly distributed in the Al matrix.

  20. Propagation of ultrasonic Love waves in nonhomogeneous elastic functionally graded materials.

    Science.gov (United States)

    Kiełczyński, P; Szalewski, M; Balcerzak, A; Wieja, K

    2016-02-01

    This paper presents a theoretical study of the propagation behavior of ultrasonic Love waves in nonhomogeneous functionally graded elastic materials, which is a vital problem in the mechanics of solids. The elastic properties (shear modulus) of a semi-infinite elastic half-space vary monotonically with the depth (distance from the surface of the material). The Direct Sturm-Liouville Problem that describes the propagation of Love waves in nonhomogeneous elastic functionally graded materials is formulated and solved by using two methods: i.e., (1) Finite Difference Method, and (2) Haskell-Thompson Transfer Matrix Method. The dispersion curves of phase and group velocity of surface Love waves in inhomogeneous elastic graded materials are evaluated. The integral formula for the group velocity of Love waves in nonhomogeneous elastic graded materials has been established. The effect of elastic non-homogeneities on the dispersion curves of Love waves is discussed. Two Love wave waveguide structures are analyzed: (1) a nonhomogeneous elastic surface layer deposited on a homogeneous elastic substrate, and (2) a semi-infinite nonhomogeneous elastic half-space. Obtained in this work, the phase and group velocity dispersion curves of Love waves propagating in the considered nonhomogeneous elastic waveguides have not previously been reported in the scientific literature. The results of this paper may give a deeper insight into the nature of Love waves propagation in elastic nonhomogeneous functionally graded materials, and can provide theoretical guidance for the design and optimization of Love wave based devices. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Characterization of functionally graded elastic materials using a thickness-shear mode quartz resonator

    Science.gov (United States)

    Chen, Yangyang; Wang, Ji; Du, Jianke; Yang, Jiashi

    2013-06-01

    We propose the use of a quartz crystal plate thickness-shear (TSh) mode resonator to measure material property variations in a functionally graded material (FGM). A theoretical analysis is performed on TSh vibrations of an AT-cut quartz plate carrying a layer of an FGM whose density and stiffness vary along its thickness. The effect of the material property gradient on the resonant frequencies of the two-layer plate as a compound resonator is examined. It is shown that this effect may be used to measure the material property gradient of the FGM.

  2. A Bibliography of English as a Second Language Materials: Grades K-3.

    Science.gov (United States)

    National Clearinghouse for Bilingual Education, Arlington, VA.

    This annotated bibliography of English as a second language (ESL) materials for grades K-3 is divided into four parts. The first part, ESL texts, lists a number of series or single texts that are designed to teach the spoken language and reading to the elementary school child. The second part is a list of readers that, although were mostly…

  3. Electromagnetic Spectrum. 7th and 8th Grade Agriculture Science Curriculum. Teacher Materials.

    Science.gov (United States)

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This curriculum guide, the second in a set of six, contains teacher and student materials for a unit on the electromagnetic spectrum prepared as part of a seventh- and eighth-grade agricultural science curriculum that is integrated with science instruction. The guide contains the state goals and sample learning objectives for each goal for…

  4. The Hawaiian Monarchy: Instructional Materials/Resources for Grade 7 Social Studies. Draft.

    Science.gov (United States)

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    Materials in this curriculum guide for a seventh grade social studies course focus on the development of the monarchy period in Hawaii's history. Following a course outline, 10 study units cover map skills, early historical background, and the reigns of the following kings and queens: Kamehameha, Liholiho, Kauikeaouli, Alexander Liholiho, Lot,…

  5. Dynamic properties of symmetric and asymmetric Beams made of Functionally Graded materials in bending

    Science.gov (United States)

    Diveyev, B.; Butyter, I.; Pelekh, Ya.

    2018-03-01

    A theory of dynamic bending of beams made of functionally graded materials is presented. The refined theoretical model takes into account the shear and normal strains and stresses. The distribution of stresses in the beams in cylindrical bending at different vibration frequencies is considered. Their damping properties in the frequency range are estimated.

  6. Analysis of Sigmoid Functionally Graded Material (S-FGM) Nanoscale Plates Using the Nonlocal Elasticity Theory

    OpenAIRE

    Jung, Woo-Young; Han, Sung-Cheon

    2013-01-01

    Based on a nonlocal elasticity theory, a model for sigmoid functionally graded material (S-FGM) nanoscale plate with first-order shear deformation is studied. The material properties of S-FGM nanoscale plate are assumed to vary according to sigmoid function (two power law distribution) of the volume fraction of the constituents. Elastic theory of the sigmoid FGM (S-FGM) nanoscale plate is reformulated using the nonlocal differential constitutive relations of Eringen and first-order shear defo...

  7. Manufacture of ribbon and solar cells of material of semiconductor grade

    International Nuclear Information System (INIS)

    1980-01-01

    A method is described of producing ribbon-like substantially monocrystalline bodies of silicon or other materials of semiconductor grade suitable for use in solar cells or other semiconductor devices. A tube of the material is made and a photovoltaic junction formed in it. The tube is then divided lengthwise into a number of ribbon-like bodies. The photovoltaic junction can be formed either by diffusion or by ion-implantation. (U.K.)

  8. Analysis of longitudinal cracked two-dimensional functionally graded beams exhibiting material non-linearity

    Directory of Open Access Journals (Sweden)

    Victor Rizov

    2017-07-01

    Full Text Available An analytical study of longitudinal fracture in two-dimensional functionally graded cantilever beam configurations is carried-out with taking into account the non-linear behavior of material. A longitudinal crack is located arbitrary along the beam cross-section height. The material is functionally graded along the width as well as along the height of beam. The external loading consists of a bending moment applied at the free end of lower crack arm. Fracture is studied in terms of the strain energy release rate by considering the beam complementary strain energy. The solution derived is verified by analyzing the longitudinal crack with the help of the J-integral. The distribution of J-integral value along the crack front is studied. The effects of crack location, material gradients and non-linear behavior of material on the fracture are elucidated. The analysis reveals that the material non-linearity has to be taken into account in fracture mechanics based safety design of structural members and components made of two-dimensional functionally graded materials.

  9. PENGARUH PENGGUNAAN GAS PELINDUNG ARGON GRADE A DAN GRADE C TERHADAP KEKUATAN TARIK LASAN SAMBUNGAN BUTT PADA MATERIAL KAPAL ALUMINIUM 5083

    Directory of Open Access Journals (Sweden)

    Hartono Yudo

    2012-04-01

    Full Text Available Material aluminum 5083 banyak digunakan dalam industri perkapalan khususnya sebagai material konstruksi kapal aluminium. Jika dilakukan pengelasan untuk penyambungan material aluminum 5083 akan terdapat kekurangsempurnaan hasil  pengelasanya ditinjau dari kekuatanya. Penelitian ini bertujuan mengetahui kekuatan tarik hasil las material aluminum 5083 dengan menggunakan dua jenis gas pelindung yang berbeda yakni argon grade A dan argon grade C. Pada perancangan percobaan ini menggunakan material kapal aluminium crew boat KM. Pan Maitime dengan LOA (length over all 35 m, yaitu material aluminium 5083 dengan ketebalan 6 mm dengan Elektrode ER 5356 sesuai rekomdeasi ANSI/ AWS spesification A 5 10/ A 5 10 M dengan  proses pengelasan MIG (metal inert gas. Hasil penelitian menunjukan  bahwa penggunaan gas pelindung argon grade C sebagai gas pelindung pengelasan material aluminum 5083 memiliki kekuatan tarik yang lebih besar 57,89 %  untuk spesimen sambungan las dan 19,85 %  untuk spesimen logam las (weld metal daripada gas pelindung argon grade A. Dimana kekuatan tarik (s rata-rata spesimen sambungan las menggunakan argon grade C adalah 202.5 N/mm2, dan spesimen sambungan las menggunakan argon grade A adalah 128.25 N/mm2, sedangkan untuk kekuatan tarik (s rata-rata spesimen logam las menggunakan argon grade C adalah 299,01 N/mm2, dan spesimen logam las menggunakan argon grade A adalah  249,47 N/mm2. Selain pengujian juga dilakukan analisa menggunakan software Nastran 4.5  dengan hasil tegangan spesimen 111,40 N/mm2 untuk beban tarik 7700 N yang terjadi pada sambungan las.

  10. Material Structure of a Graded Refractive Index Lens in Decapod Squid

    Science.gov (United States)

    Cai, Jing; Heiney, Paul; Sweeney, Alison

    2013-03-01

    Underwater vision with a camera-type eye that is simultaneously acute and sensitive requires a spherical lens with a graded distribution of refractive index. Squids have this type of lens, and our previous work has shown that its optical properties are likely achieved with radially variable densities of a single protein with multiple isoforms. Here we measure the spatial organization of this novel protein material in concentric layers of the lens and use these data to suggest possible mechanisms of self-assembly of the proteins into a graded refractive index structure. First, we performed small angle x-ray scattering (SAXS) to study how the protein is spatially organized. Then, molecular dynamic simulation allowed us to correlate structure to the possible dynamics of the system in different regions of the lens. The combination of simulation and SAXS data in this system revealed the likely protein-protein interactions, resulting material structure and its relationship to the observed and variable optical properties of this graded index system. We believe insights into the material properties of the squid lens system will inform the invention of self-assembling graded index devices.

  11. Research on Free Vibration Frequency Characteristics of Rotating Functionally Graded Material Truncated Conical Shells with Eccentric Functionally Graded Material Stringer and Ring Stiffeners

    Directory of Open Access Journals (Sweden)

    Dao Van Dung

    Full Text Available Abstract In this research work, an exact analytical solution for frequency characteristics of the free vibration of rotating functionally graded material (FGM truncated conical shells reinforced by eccentric FGM stringers and rings has been investigated by the displacement function method. Material properties of shell and stiffeners are assumed to be graded in the thickness direction according to a simple power law distribution. The change of spacing between stringers is considered. Using the Donnell shell theory, Leckhnisky smeared stiffeners technique and taking into account the influences of centrifugal force and Coriolis acceleration the governing equations are derived. For stiffened FGM conical shells, it is difficult that free vibration equations are a couple set of three variable coefficient partial differential equations. By suitable transformations and applying Galerkin method, this difficulty is overcome in the paper. The sixth order polynomial equation for w is obtained and it is used to analyze the frequency characteristics of rotating ES-FGM conical shells. Effects of stiffener, geometrics parameters, cone angle, vibration modes and rotating speed on frequency characteristics of the shell forward and backward wave are discussed in detail. The present approach proves to be reliable and accurate by comparing with published results available in the literature.

  12. Ductile fracture toughness of modified A 302 grade B plate materials. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D.E.; Manneschmidt, E.T.; Swain, R.L.

    1997-02-01

    The objective of this work was to develop ductile fracture toughness data in the form of J-R curves for modified A 302 grade B plate materials typical of those used in fabricating reactor pressure vessels. A previous experimental study at Materials Engineering Associates (MEA) on one particular heat of A 302 grade B plate showed decreasing J-R curves with increased specimen thickness. This characteristic has not been observed in numerous tests made on the more recent production materials of A 533 grade B and A 508 class 2 pressure vessel steels. It was unknown if the departure from norm for the MEA material was a generic characteristic for all heats of A 302 grade B steels or just unique to that one particular plate. Seven heats of modified A 302 grade B steel and one heat of vintage A 533 grade B steel were provided to this project by the General Electric Company of San Jose, California. All plates were tested for chemical content, tensile properties, Charpy transition temperature curves, drop-weight nil-ductility transition (NDT) temperature, and J-R curves. Tensile tests were made in the three principal orientations and at four temperatures, ranging from room temperature to 550{degrees}F (288{degrees}C). Charpy V-notch transition temperature curves were obtained in longitudinal, transverse, and short transverse orientations. J-R curves were made using four specimen sizes (1/2T, IT, 2T, and 4T). None of the seven heats of modified A 302 grade showed size effects of any consequence on the J-R curve behavior. Crack orientation effects were present, but none were severe enough to be reported as atypical. A test temperature increase from 180 to 550{degrees}F (82 to 288{degrees}C) produced the usual loss in J-R curve fracture toughness. Generic J-R curves and mathematical curve fits to the same were generated to represent each heat of material. This volume is a compilation of all data developed.

  13. Ductile fracture toughness of modified A 302 Grade B Plate materials, data analysis. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D.E.; Manneschmidt, E.T.; Swain, R.L.

    1997-01-01

    The goal of this work was to develop ductile fracture toughness data in the form of J-R curves for modified A302 grade B plate materials typical of those used in reactor pressure vessels. A previous experimental study on one heat of A302 grade B plate showed decreasing J-R curves with increased specimen thickness. This characteristic has not been observed in tests made on recent production materials of A533 grade B and A508 class 2 pressure vessel steels. It was unknown if the departure from norm for the material was a generic characteristic for all heats of A302 grade B steels or unique to that particular plate. Seven heats of modified A302 grade B steel and one heat of vintage A533 grade B steel were tested for chemical content, tensile properties, Charpy transition temperature curves, drop-weight nil-ductility transition (NDT) temperature, and J-R curves. Tensile tests were made in the three principal orientations and at four temperatures, ranging from room temperature to 550F. Charpy V-notch transition temperature curves were obtained in longitudinal, transverse, and short transverse orientations. J-R curves were made using four specimen sizes (1/2T, 1T, 2T, and 4T). The fracture mechanics-based evaluation method covered three test orientations and three test temperatures (80, 400, and 550F). However, the coverage of these variables was contingent upon the amount of material provided. Drop-weight NDT temperature was determined for the T-L orientation only. None of the heats of modified A302 grade B showed size effects of any consequence on the J-R curve behavior. Crack orientation effects were present, but none were severe enough to be reported as atypical. A test temperature increase from 180 to 550F produced the usual loss in J-R curve fracture toughness. Generic J-R curves and curve fits were generated to represent each heat of material. This volume deals with the evaluation of data and the discussion of technical findings. 8 refs., 18 figs., 8 tabs.

  14. Ductile fracture toughness of modified A 302 grade B plate materials. Volume 2

    International Nuclear Information System (INIS)

    McCabe, D.E.; Manneschmidt, E.T.; Swain, R.L.

    1997-02-01

    The objective of this work was to develop ductile fracture toughness data in the form of J-R curves for modified A 302 grade B plate materials typical of those used in fabricating reactor pressure vessels. A previous experimental study at Materials Engineering Associates (MEA) on one particular heat of A 302 grade B plate showed decreasing J-R curves with increased specimen thickness. This characteristic has not been observed in numerous tests made on the more recent production materials of A 533 grade B and A 508 class 2 pressure vessel steels. It was unknown if the departure from norm for the MEA material was a generic characteristic for all heats of A 302 grade B steels or just unique to that one particular plate. Seven heats of modified A 302 grade B steel and one heat of vintage A 533 grade B steel were provided to this project by the General Electric Company of San Jose, California. All plates were tested for chemical content, tensile properties, Charpy transition temperature curves, drop-weight nil-ductility transition (NDT) temperature, and J-R curves. Tensile tests were made in the three principal orientations and at four temperatures, ranging from room temperature to 550 degrees F (288 degrees C). Charpy V-notch transition temperature curves were obtained in longitudinal, transverse, and short transverse orientations. J-R curves were made using four specimen sizes (1/2T, IT, 2T, and 4T). None of the seven heats of modified A 302 grade showed size effects of any consequence on the J-R curve behavior. Crack orientation effects were present, but none were severe enough to be reported as atypical. A test temperature increase from 180 to 550 degrees F (82 to 288 degrees C) produced the usual loss in J-R curve fracture toughness. Generic J-R curves and mathematical curve fits to the same were generated to represent each heat of material. This volume is a compilation of all data developed

  15. Ductile fracture toughness of modified A 302 Grade B Plate materials, data analysis. Volume 1

    International Nuclear Information System (INIS)

    McCabe, D.E.; Manneschmidt, E.T.; Swain, R.L.

    1997-01-01

    The goal of this work was to develop ductile fracture toughness data in the form of J-R curves for modified A302 grade B plate materials typical of those used in reactor pressure vessels. A previous experimental study on one heat of A302 grade B plate showed decreasing J-R curves with increased specimen thickness. This characteristic has not been observed in tests made on recent production materials of A533 grade B and A508 class 2 pressure vessel steels. It was unknown if the departure from norm for the material was a generic characteristic for all heats of A302 grade B steels or unique to that particular plate. Seven heats of modified A302 grade B steel and one heat of vintage A533 grade B steel were tested for chemical content, tensile properties, Charpy transition temperature curves, drop-weight nil-ductility transition (NDT) temperature, and J-R curves. Tensile tests were made in the three principal orientations and at four temperatures, ranging from room temperature to 550F. Charpy V-notch transition temperature curves were obtained in longitudinal, transverse, and short transverse orientations. J-R curves were made using four specimen sizes (1/2T, 1T, 2T, and 4T). The fracture mechanics-based evaluation method covered three test orientations and three test temperatures (80, 400, and 550F). However, the coverage of these variables was contingent upon the amount of material provided. Drop-weight NDT temperature was determined for the T-L orientation only. None of the heats of modified A302 grade B showed size effects of any consequence on the J-R curve behavior. Crack orientation effects were present, but none were severe enough to be reported as atypical. A test temperature increase from 180 to 550F produced the usual loss in J-R curve fracture toughness. Generic J-R curves and curve fits were generated to represent each heat of material. This volume deals with the evaluation of data and the discussion of technical findings. 8 refs., 18 figs., 8 tabs

  16. Determination of the Local Thermal Conductivity of Functionally Graded Materials by a Laser Flash Method

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub; Heiselberg, Per

    2013-01-01

    Determination of thermal conductivity of construction materials is essential to estimate their insulation capabilities. In most cases, homogenous materials are used and well developed methods exist for measurements of their thermal conductivity. The task becomes more challenging when dealing...... by scanning them point by point and determining the thermal conductivity as a function of the spatial dimensions. The method proves to be repeatable and of reasonable accuracy and can be used to determine the local thermal properties on a scale of millimeters. In this study, the method was successfully...... applied to create a map of thermal conductivity of a functionally graded material sample....

  17. Vibration and buckling characteristics of functionally graded nanoplates subjected to thermal loading based on surface elasticity theory

    Science.gov (United States)

    Ansari, R.; Ashrafi, M. A.; Pourashraf, T.; Sahmani, S.

    2015-04-01

    The buckling and vibration responses of nanoplates made of functionally graded materials (FGMs) subjected to thermal loading are studied in prebuckling domain with considering the effect of surface stress. To accomplish this purpose, Gurtin-Murdoch elasticity theory is incorporated into the classical plate theory to develop a non-classical plate model including the surface effects. The material properties of FGM nanoplate are considered to be graded in the thickness direction on the basis of the power law function. Hamilton's principle is utilized to derive size-dependent governing differential equations of motion and associated boundary conditions. Selected numerical results are presented to indicate the importance of surface stress effect. It is revealed that in the presence of surface stress effect, the influence of material property gradient index on the critical thermal buckling load is more prominent for FGM nanoplates with lower length-to-thickness ratios. Also, by increasing the natural frequency of FGM nanoplate, the role of surface stress effect in the value of critical thermal buckling load is more prominent.

  18. Method and apparatus for determination of mechanical properties of functionally-graded materials

    Science.gov (United States)

    Giannakopoulos, Antonios E.; Suresh, Subra

    1999-01-01

    Techniques for the determination of mechanical properties of homogenous or functionally-graded materials from indentation testing are presented. The technique is applicable to indentation on the nano-scale through the macro-scale including the geological scale. The technique involves creating a predictive load/depth relationship for a sample, providing an experimental load/depth relationship, comparing the experimental data to the predictive data, and determining a physical characteristic from the comparison.

  19. Supply of equipment and components, materials of dedicated commercial grade, other services

    International Nuclear Information System (INIS)

    Perdices, D.; Perez Medina, E.

    2014-01-01

    The following article describes the course of action of Tecnatom as Procurement Agent and Manufacturing Manager for the supply materials, equipment and components for the Spanish Nuclear Power Plants. We have devoted a special mention to the supply of dedicated commercial grade items (CGI), bringing together the services of Manufacturing Manager, Engineering service and testing facilities, simplifying the control of the supply chain with total warranty. (Author)

  20. Static Response of Functionally Graded Material Plate under Transverse Load for Varying Aspect Ratio

    Directory of Open Access Journals (Sweden)

    Manish Bhandari

    2014-01-01

    Full Text Available Functionally gradient materials (FGM are one of the most widely used materials in various applications because of their adaptability to different situations by changing the material constituents as per the requirement. Nowadays it is very easy to tailor the properties to serve specific purposes in functionally gradient material. Most structural components used in the field of engineering can be classified as beams, plates, or shells for analysis purposes. In the present study the power law, sigmoid law and exponential distribution, is considered for the volume fraction distributions of the functionally graded plates. The work includes parametric studies performed by varying volume fraction distributions and aspect ratio. The FGM plate is subjected to transverse UDL (uniformly distributed load and point load and the response is analysed.

  1. Weapons-grade nuclear material - open questions of a safe disposal

    International Nuclear Information System (INIS)

    Closs, K.D.; Giraud, J.P.; Grill, K.D.; Hensing, I.; Hippel, F. von; Holik, J.; Pellaud, B.

    1995-01-01

    There are suitable technologies available for destruction of weapons-grade uranium and plutonium. Weapons-grade uranium, consisting to 90% of the isotope U-235, can be diluted with the uranium isotope U-238 to make it non-weapons-grade, but it will then still be a material that can be used as a fuel in civil nuclear reactors. For safe plutonium disposal, several options are under debate. There is for instance a process called ''reverse reprocessing'', with the plutonium being blended with high-level radioactive fission products and then being put into a waste form accepted for direct ultimate disposal. The other option is to convert weapons-grade plutonium into MOX nuclear fuel elements and then ''burn'' them in civil nuclear power reactors. This is an option favoured by many experts. Such fuel elements should stay for a long time in the reactor core in order to achieve high burnups, and should then be ready for ultimate disposal. This disposal pathway offers essential advantages: the plutonium is used up or depleted as a component of reactor fuel, and thus is no longer available for illegal activities, and it serves as an energy source for power generation. (orig./HP) [de

  2. Thermal Stress Analysis of W/Cu Functionally Graded Materials by Using Finite Element Method

    Science.gov (United States)

    Yang, Zhenxiao; Liu, Min; Deng, Chunming; Zhang, Xiaofeng; Deng, Changguang

    2013-03-01

    Copper alloys with tungsten coating shows an excellent plasma irradiation resistance, however, the difference of coefficient thermal expansion between W and Cu makes it really a difficult job to prepare over 1 mm W coating with high adhesive strength. Functionally graded material (FGM) seems to be an effective method to improve the adhesive strength of thick W coating. This paper focused on the finite element simulation on thermal stress for W/Cu FGM with different graded layers, composition and thicknesses. In addition, the variance of stresses for functionally graded coatings with the steady state heat flux were simulated by finite element analysis (ANSYS Workbench). The results showed that the W/Cu FGM was effectively beneficial for the stress relief of W coating. Meanwhile, the maximum von mises stress decreased approximately by 52.8 % compared to monolithic W plasma facing material. And the four-layer FGM with a compositional exponent of 2 was optimum for 1.5 mm W coating.

  3. Optimization of Natural Frequencies and Sound Power of Beams Using Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Nabeel T. Alshabatat

    2014-01-01

    Full Text Available This paper presents a design method to optimize the material distribution of functionally graded beams with respect to some vibration and acoustic properties. The change of the material distribution through the beam length alters the stiffness and the mass of the beam. This can be used to alter a specific beam natural frequency. It can also be used to reduce the sound power radiated from the vibrating beam. Two novel volume fraction laws are used to describe the material volume distributions through the length of the FGM beam. The proposed method couples the finite element method (for the modal and harmonic analysis, Lumped Parameter Model (for calculating the power of sound radiation, and an optimization technique based on Genetic Algorithm. As a demonstration of this technique, the optimization procedure is applied to maximize the fundamental frequency of FGM cantilever and clamped beams and to minimize the sound radiation from vibrating clamped FGM beam at a specific frequency.

  4. Analysis of macro and micro residual stresses in functionally graded materials by diffraction methods

    CERN Document Server

    Dantz, D; Reimers, W

    1999-01-01

    The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO/sub 2//Ni and 8Y-ZrO/sub 2//NiCr8020, respectively, was analysed by non- destructive diffraction methods. In $9 order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using $9 conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion $9 (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. (7 refs).

  5. Chemical characterization of detector grade materials: facilities and expertise at CCCM

    International Nuclear Information System (INIS)

    Kumar, Sunil Jai.

    2009-01-01

    High purity materials at present being analysed at CCCM are Ga, Ge, Te, In, Sb, Cd at ultra trace analysis and SiO 2 , As 2 O 3 at bulk analysis facilities. The methods adopted use clean lab technology with wet chemical processing. Detection limits obtained in these methods are in parts per billion which is suitable for analysis of 99.9999 (6N) to 99.99999 (7N) pure materials. Analysis of detector grade single crystals places new challenges as the purity levels are an order or more than the above materials. The conventional methods may not work. Therefore newer methods preferably without any sample preparation with very high sensitivity has to be explored and applied. (author)

  6. A novel method for characterizing the impact response of functionally graded plates

    Science.gov (United States)

    Larson, Reid A.

    Functionally graded material (FGM) plates are advanced composites with properties that vary continuously through the thickness of the plate. Metal-ceramic FGM plates have been proposed for use in thermal protection systems where a metal-rich interior surface of the plate gradually transitions to a ceramic-rich exterior surface of the plate. The ability of FGMs to resist impact loads must be demonstrated before using them in high-temperature environments in service. This dissertation presents a novel technique by which the impact response of FGM plates is characterized for low-velocity, low- to medium-energy impact loads. An experiment was designed where strain histories in FGM plates were collected during impact events. These strain histories were used to validate a finite element simulation of the test. A parameter estimation technique was developed to estimate local material properties in the anisotropic, non-homogenous FGM plates to optimize the finite element simulations. The optimized simulations captured the physics of the impact events. The method allows research & design engineers to make informed decisions necessary to implement FGM plates in aerospace platforms.

  7. Rayleigh wave behavior in functionally graded magneto-electro-elastic material

    Science.gov (United States)

    Ezzin, Hamdi; Mkaoir, Mohamed; Amor, Morched Ben

    2017-12-01

    Piezoelectric-piezomagnetic functionally graded materials, with a gradual change of the mechanical and electromagnetic properties have greatly applying promises. Based on the ordinary differential equation and stiffness matrix methods, a dynamic solution is presented for the propagation of the wave on a semi-infinite piezomagnetic substrate covered with a functionally graded piezoelectric material (FGPM) layer. The materials properties are assumed to vary in the direction of the thickness according to a known variation law. The phase and group velocity of the Rayleigh wave is numerically calculated for the magneto-electrically open and short cases, respectively. The effect of gradient coefficients on the phase velocity, group velocity, coupled magneto-electromechanical factor, on the stress fields, the magnetic potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the hetero-structure PZT-5A/CoFe2O4; the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Rayleigh wave propagation behavior.

  8. An exact solution of mechanical buckling for functionally graded material bimorph circular plates

    Directory of Open Access Journals (Sweden)

    Jafar Eskandari Jam

    2013-03-01

    Full Text Available Presented herein is the exact solution of mechanical buckling response of FGM (Functionally Graded Material bimorph circular plates, performed under uniform radial compression, by means of the classic theory and the non-linear Von-Karman assumptions, for both simply supported and clamped boundary conditions. Material properties are assumed to be symmetric with respect to the middle surface and are graded in the thickness direction according to a simple power law, in a way that the middle surface is pure metal and the two sides are pure ceramic. Using the energy method the non-linear equilibrium equations are derived and the stability equations have been used, so as to determine the critical buckling pressure, considering the adjacent equilibrium criterion, and finally a closed-form solution has been achieved for it. The effect of different factors, including thickness to radius variation rate of the plate, volumetric percentage of material index, and Poisson's ratio on the critical buckling compression have been investigated for two simply supported and clamped boundary conditions, and the results

  9. Semi-analytical Vibration Characteristics of Rotating Timoshenko Beams Made of Functionally Graded Materials

    Directory of Open Access Journals (Sweden)

    Farzad Ebrahimia

    Full Text Available AbstractFree vibration analysis of rotating functionally graded (FG thick Timoshenko beams is presented. The material properties of FG beam vary along the thickness direction of the constituents according to power law model. Governing equations are derived through Hamilton's principle and they are solved applying differential transform method. The good agreement between the results of this article and those available in literature validated the presented approach. The emphasis is placed on investigating the effect of several beam parameters such as constituent volume fractions, slenderness ratios, rotational speed and hub radius on natural frequencies and mode shapes of the rotating thick FG beam.

  10. Enriched Element-Free Galerkin Method for Fracture Analysis of Functionally Graded Piezoelectric Materials

    Directory of Open Access Journals (Sweden)

    Guang Wei Meng

    2015-01-01

    Full Text Available A new method using the enriched element-free Galerkin method (EEFGM to model functionally graded piezoelectric materials (FGPMs with cracks was presented. To improve the solution accuracy, extended terms were introduced into the approximation function of the conventional element-free Galerkin method (EFGM to describe the displacement and electric fields near the crack. Compared with the conventional EFGM, the new approach requires smaller domain to describe the crack-tip singular field. Additionally, the domain of the nodes was not affected by the crack. Therefore, the visibility method and the diffraction method were no longer needed. The mechanical response of FGPM was discussed, when its material parameters changed exponentially in a certain direction. The modified J-integrals for FGPM were deduced, whose results were compared with the results of the conventional EFGM and the analytical solution. Numerical example results illustrated that this method is feasible and precise.

  11. Three-dimensional vibration analysis of functionally graded material plates in thermal environment

    Science.gov (United States)

    Li, Q.; Iu, V. P.; Kou, K. P.

    2009-07-01

    Free vibration of functionally graded material rectangular plates with simply supported and clamped edges in the thermal environment is studied based on the three-dimensional linear theory of elasticity. Simply supported and clamped FGM plates with temperature-dependent material properties subjected to uniform temperature rise, linear temperature rise and nonlinear temperature rise are considered. The three displacements of the plates are expanded by a series of Chebyshev polynomials multiplied by appropriate functions to satisfy the essential boundary conditions. The natural frequencies are obtained by Ritz method. The numerical results of the present approach are compared with the results of other researchers for the validation. Parametric study is performed for supported conditions, temperature fields, volume fraction indices of FGM plates.

  12. Energy trapping of thickness-shear vibration modes of elastic plates with functionally graded materials.

    Science.gov (United States)

    Wang, Ji; Yang, Jiashi; Li, Jiangyu

    2007-03-01

    Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly.

  13. Synthesis and Characterization of High Aluminum Zeolite X from Technical Grade Materials

    Directory of Open Access Journals (Sweden)

    Seyed Kamal Masoudian

    2013-06-01

    Full Text Available Zeolites are widely used as ion exchangers, adsorbents, separation materials and catalyst due to their well-tailored and highly-reproducible structures; therefore, the synthesis of zeolite from low grade resources can be interested. In the present work, high aluminum zeolite X was prepared from mixing technical grade sodium aluminate and sodium silicate solutions at temperatures between 70°C and 100°C. The synthesized zeolite X was characterized by SEM and X-ray methods according to ASTM standard procedures. The results showed that aging of the synthesis medium at the room temperature considerably increased the selectivity of zeolite X formation. On the other hand, high temperature of reaction mixture during crystallization formed zeolite A in the product; therefore, it decreased the purity of zeolite X. In addition, it was found that increasing H2O/Na2O and decreasing Na2O/SiO2 molar ratios in the reaction mixture resulted product with higher purity. © 2013 BCREC UNDIP. All rights reservedReceived: 7th January 2013; Revised: 7th April 2013; Accepted: 19th April 2013[How to Cite: Masoudian, S. K., Sadighi, S., Abbasi, A. (2013. Synthesis and Characterization of High Alu-minum Zeolite X from Technical Grade Materials. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 54-60. (doi:10.9767/bcrec.8.1.4321.54-60][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4321.54-60] | View in  |

  14. Functionally graded ceramic materials for high temperature applications for space planes

    Energy Technology Data Exchange (ETDEWEB)

    Laux, T.; Auweter-Kurtz, M. [Stuttgart Univ. (Germany). Inst. for Space Syst.; Killinger, A.; Gadow, R.; Wilhelmi, H.

    1999-10-01

    Whether it is possible to develop a fully reusable space vehicle essentially depends, according to the current point of view, on the success of developing appropriate thermal protection materials. Functionally graded materials are being developed for this purpose. This paper presents first results of the manufacturing of graded coatings and their investigation under high enthalpy flow conditions. The materials were manufactured by atmospheric plasma spraying (APS) at the Institute for Manufacturing Technologies of Ceramic Components and Composites (IFKB). The TPS is made up of principally three layers: a substrate, an intermediate layer and the appropriate thermal protection layer. The substrate is the high melting alloy Inconel 625. In addition to the improvement of the adhesive power between the top layer and the substrate the intermediate layer acts as an oxygen barrier. Cr{sub 3}C{sub 2}-NiCr, NiCrAlY and Mo-MoSi{sub 2} are investigated as intermediate layer materials. ZrO{sub 2} and TiO{sub 2} are used for the TPS surface. First investigations of the selection of surface and intermediate layers were carried out. The investigation of the erosion behaviour was performed within a plasma wind tunnel at the Institute for Space Systems (IRS). The circular samples are loaded by a high enthalpy flow produced by a magnetoplasmadynamic generator (MPG). The test conditions were determined by measurements of the heat flux and the Pitot pressure. The surface temperature of the test sample is measured by pyrometers. The effects of thermal and chemical loads on the sample are presented. (orig.) 15 refs.

  15. Source separation for materials recovery guidelines. Part 246. [High-grade paper, corrugated container, and residential materials recovery

    Energy Technology Data Exchange (ETDEWEB)

    1976-04-23

    These guidelines are issued under the Authority of Section 209(a) of the Solid Waste Disposal Act of 1965 (PL 89-272), as amended by the Resource Recovery Act of 1970 (PL 91-512). Chapter I of Title 40 of the Code of Federal Regulations is amended effective May 24, 1976 by adding a new Part 246. The guidelines are applicable to the source separation of residential, commercial, and institutional solid wastes. Explicitly excluded are mining, agricultural, and industrial solid wastes; hazardous wastes; sludges; construction and demolition wastes; infectious wastes; classified waste. Specific requirements and recommended procedures for high-grade paper recovery, residential materials recovery, and corrugated container recovery are included in Part 246. (MCW)

  16. Solid freeform fabrication of biological materials

    Science.gov (United States)

    Wang, Jiwen

    This thesis investigates solid freeform fabrication of biological materials for dental restoration and orthopedic implant applications. The basic approach in this study for solid freeform fabrication of biological materials is micro-extrusion of single or multiple slurries for 3D components and inkjet color printing of multiple suspensions for functionally graded materials (FGMs). Common issues associated with micro-extrusion and inkjet color printing are investigated. These common issues include (i) formulation of stable slurries with a pseudoplastic property, (ii) cross-sectional geometry of the extrudate as a function of the extrusion parameters, (iii) fabrication path optimization for extrusion process, (iv) extrusion optimization for multi-layer components, (v) composition control in functionally graded materials, and (vi) sintering optimization to convert the freeform fabricated powder compact to a dense body for biological applications. The present study clearly shows that the rheological and extrusion behavior of dental porcelain slurries depend strongly on the pH value of the slurry and extrusion conditions. A slurry with pseudoplastic properties is a basic requirement for obtaining extruded lines with rectangular cross-sections. The cross-sectional geometry of the extrudate is also strongly affected by extrusion parameters including the extrusion nozzle height, nozzle moving speed, extrusion rate, and critical nozzle height. Proper combinations of these extrusion parameters are necessary in order to obtain single line extrudates with near rectangular cross-sections and 3D objects with dimensional accuracy, uniform wall thickness, good wall uprightness, and no wall slumping. Based on these understandings, single-wall, multi-wall, and solid teeth have been fabricated via micro-extrusion of the dental slurry directly from a CAD digital model in 30 min. Inkjet color printing using stable Al2O3 and ZrO 2 aqueous suspensions has been developed to fabricate

  17. Transverse vibration of pipe conveying fluid made of functionally graded materials using a symplectic method

    International Nuclear Information System (INIS)

    Wang, Zhong-Min; Liu, Yan-Zhuang

    2016-01-01

    Highlights: • We investigate the transverse vibration of FGM pipe conveying fluid. • The FGM pipe conveying fluid can be classified into two cases. • The variations between the frequency and the power law exponent are obtained. • “Case 1” is relatively more reasonable than “case 2”. - Abstract: Problems related to the transverse vibration of pipe conveying fluid made of functionally graded material (FGM) are addressed. Based on inside and outside surface material compositions of the pipe, FGM pipe conveying fluid can be classified into two cases. It is hypothesized that the physical parameters of the material along the direction of the pipe wall thickness change in the simple power law. A differential equation of motion expressed in non-dimensional quantities is derived by using Hamilton's principle for systems of changing mass. Using the assuming modal method, the pipe deflection function is expanded into a series, in which each term is expressed to admissible function multiplied by generalized coordinate. Then, the differential equation of motion is discretized into the two order differential equations expressed in the generalized coordinates. Based on symplectic elastic theory and the introduction of dual system and dual variable, Hamilton's dual equations are derived, and the original problem is reduced to eigenvalue and eigenvector problem in the symplectic space. Finally, a symplectic method is employed to analyze the vibration and stability of FGM pipe conveying fluid. For a clamped–clamped FGM pipe conveying fluid in “case 1” and “case 2”, the dimensionless critical flow velocity for first-mode divergence and the critical coupled-mode flutter flow velocity are obtained, and the variations between the real part and imaginary part of dimensionless complex frequency and fluid velocity, mass ratio and the power law exponent (or graded index, volume fraction) for FGM pipe conveying fluid are analyzed.

  18. PREFACE: 12th International Symposium on Multiscale, Multifunctional and Functionally Graded Materials (FGM 2012)

    Science.gov (United States)

    Zhou, Zhangjian; Li, Jingfeng; Zhang, Lianmeng; Ge, Changchun

    2013-03-01

    The 12th International Symposium on Multiscale, Multifunctional and Functionally Graded Materials (FGM-2012) was held in Beijing, China, from 22-36 October 2012. This was part of a series of conferences organized every two years endorsed by International Advisory Committee for FGM's, which serves as a forum for scientists, educators, engineers and young students interested in the development of functionally graded materials (FGM). The series continues from the previous international symposium on FGM held in Sendai, Japan (1990), San Francisco, USA (1992), Lausanne, Switzerland (1994), Tsukuba, Japan (1996), Dresden, Germany (1998), Estes Park, USA (2000), Beijing, China (2002), Leuven, Belgium (2004), Hawaii, USA (2006), Sendai, Japan (2008) and Guimaraes, Portugal (2010). Functionally graded materials are non-uniform materials which are designed with embodied continuous spatial variations in composition and microstructure for the specific purpose of adjusting their thermal, structural, mechanical, biological or functional response to specific application conditions. Such multi-phase materials cover a range of space and time scales, and are best understood by means of a comprehensive multiscale, multiphysics approach. These kinds of materials are presently in the forefront of materials research, receiving worldwide attention. They have a broad range of applications including for example, biomedical, biomechanical, automotive, aerospace, mechanical, civil, nuclear, and naval engineering. New applications are continuously being discovered and developed. The objective of the FGM-2012 intends to provide opportunities for exchanging ideas and discussing state-of-the-art theories, techniques and applications in the fields of multiscale, multifunctional and FGM, through invited lectures, oral and poster presentations. FGM-2012 was organized and hosted by University of Science and Technology Beijing, China, together with Tsing-hua University and Wuhan University of

  19. Study of high temperature oxidation of duplex and functionally graded materials of thermal barrier coating (FGM TBC)

    International Nuclear Information System (INIS)

    Saeedi, B.; Sabour, A. R.; Khodami, A. M.

    2008-01-01

    Although the number and the severity of thermal barrier coatings applications on hot section components have dramatically increased in the past decade, premature spallation failure of thermal barrier coatings , due to mismatch of thermal expansion at the metal/ceramic interface of the two coating layers, during service is still an overriding concern. Therefore, functionally graded materials with a gradual compositional variation have been introduced. In this study, comparison of properties of two different types of thermal barrier coatings was made to improve the surface characteristics on high temperature components. These thermal barrier coatings consisted of a duplex thermal barrier coatings and a five layered functionally graded thermal barrier coatings . In both coatings, Yttria partially stabilized Zirconia topcoat was deposited by air plasma spraying and Ni Cr Al Y bond coat was deposited by high velocity oxy fuel spraying. In functionally graded materials coating, functionally graded layer was sprayed by air plasma process by varying the feeding ratio of YSZ/Ni Cr Al Y powders using two separate powder feeders. Then, isothermal oxidation was carried out at 950 d eg C in atmosphere to obtain the plot of mass change vs. time to study oxidation kinetic. Microstructural and compositional changes of coating, oxides formed during service were examined by optical microscope and scanning electron microscopy with EDS. functionally graded materials coating failed after 2100 h and duplex coating failed after 1700 h. Finally, it was found that functionally graded materials coating is more qualified than duplex thermal barrier coatings and stands for a longer time

  20. Materials and Techniques for Teaching the Esperanto Language in the Elementary Grades [and] 1996 Packet for Teachers.

    Science.gov (United States)

    Jones, Kent

    Materials presented here include a variety of resources for teachers of Esperanto: a brief guide to Esperanto teaching, including suggested teacher qualifications, a listing of instructional materials and resources, including serials, with details of publication, activities in preparation for teaching, grade-level class activities, notes on…

  1. Buckling Analysis of Functionally Graded Material Plates Using Higher Order Shear Deformation Theory

    Directory of Open Access Journals (Sweden)

    B. Sidda Reddy

    2013-01-01

    Full Text Available The prime aim of the present study is to present analytical formulations and solutions for the buckling analysis of simply supported functionally graded plates (FGPs using higher order shear deformation theory (HSDT without enforcing zero transverse shear stresses on the top and bottom surfaces of the plate. It does not require shear correction factors and transverse shear stresses vary parabolically across the thickness. Material properties of the plate are assumed to vary in the thickness direction according to a power law distribution in terms of the volume fractions of the constituents. The equations of motion and boundary conditions are derived using the principle of virtual work. Solutions are obtained for FGPs in closed-form using Navier’s technique. Comparison studies are performed to verify the validity of the present results from which it can be concluded that the proposed theory is accurate and efficient in predicting the buckling behavior of functionally graded plates. The effect of side-to-thickness ratio, aspect ratio, modulus ratio, the volume fraction exponent, and the loading conditions on the critical buckling load of FGPs is also investigated and discussed.

  2. Effects of high gamma doses on the bulk etch rate of two grade CR-39 materials

    International Nuclear Information System (INIS)

    Brahimi, S.; Lounis-Mokrani, Z.; Imatoukene, D.; Badreddine, A.; Abdelaziz, F.Z.; Allab, M.

    2008-01-01

    In this study, the effect of gamma pre-treatment on etching rates has been investigated on CR-39 detectors manufactured by Pershore Mouldings (PM) as standard grade and (PM355) as dosimetry grade. The detectors have been exposed to 60 Co gamma rays at absorbed dose ranging from 0 to 10 5 Gy. The chemical etching was carried out in four PEW solutions (potassium ethanol in water) with various concentrations (KOH 6.25 N with 0%, 20%, 40% and 60% of ethanol). The results show that the effect of gamma rays on CR-39 etching characteristics is more pronounced when the ethanol concentration increases in the etching solution especially in the region ranging from 10 3 to 10 4 Gy. In this range, V B etching rate decreases till values less than those observed for virgin material. The structural alterations (cross linking or main chain scissions) produced by gamma rays in this plastic detector have been determined using UV-visible and FTIR spectroscopy and compared to those induced by proton irradiation

  3. Material development for grade X80 heavy-wall hot induction bends

    International Nuclear Information System (INIS)

    Wang Xu; Xiao Furen; Fu Yanhong; Chen Xiaowei; Liao Bo

    2011-01-01

    Highlights: ► The new material for X80 heavy wall thickness hot induction bend was designed. ► The continuous cooling transformation (CCT) diagrams were determined. ► The steel adapts to manufacture of X80 heavy-wall thickness hot induction bend. ► The optimum manufactural processes were obtained. ► The bending temperature is about 990 °C, and tempering is about 600 °C. - Abstract: A new steel for grade X80 heavy wall thickness hot induction bends was designed based on the chemical compositions of commercial X80 steels in this work. Then, its continuous cooling transformation (CCT) diagram was determined with Gleeble-3500 thermo-mechanical simulator. Furthermore, the effects of heat treatment technology on its microstructure and mechanical property were investigated, and the technology parameters of the heat treatment were optimized. The results show that the acicular ferrite and/or bainite transformations are promoted, the polygonal ferrite and pearlite transformation are restrained, because proper amount of alloying elements were added into the new steel. Therefore, the strength of this new steel is improved markedly, even if the cooling rate is lower, which ensure the higher strength distribution along cross section of the heavy wall thickness. It is significant for the manufacture of grade X80 heavy wall thickness hot induction bends in the second West-to-East gas transportation pipeline project of China.

  4. Buckling of rectangular functionally graded material plates subjected to nonlinearly distributed in-plane edge loads

    Science.gov (United States)

    Chen, X. L.; Liew, K. M.

    2004-12-01

    In this paper, the buckling behavior of functionally graded material (FGM) rectangular plates subjected to pin loads, partial uniform loads and parabolic loads is studied using the mesh-free method based on the radial basis function. The proposed mesh-free method approximates displacements based on scattered nodes, thus it can avoid the disadvantages that arise in the finite element method (FEM) from the use of elements. Variational forms of the system equations for the calculation of non-uniform prebuckling stress distribution and buckling loads of the plate are established. Two-step solution procedures are implemented. First the non-uniform prebuckling stresses are obtained based on a two-dimensional (2D) elastic plane stress problem. Then buckling loads of plates with the predetermined non-uniform prebuckling stresses are calculated based on Mindlin's plate assumption. Selected numerical examples are presented to validate the proposed mesh-free method.

  5. Three-dimensional vibration analysis of functionally graded material sandwich plates

    Science.gov (United States)

    Li, Q.; Iu, V. P.; Kou, K. P.

    2008-03-01

    Free vibration of functionally graded material sandwich rectangular plates with simply supported and clamped edges is studied based on the three-dimensional linear theory of elasticity. Two common types of FGM sandwich plates, namely, the sandwich with FGM facesheet and homogeneous core and the sandwich with homogeneous facesheet and FGM core, are considered. The three displacements of the plates are expanded by a series of Chebyshev polynomials multiplied by appropriate functions to satisfy the essential boundary conditions. The natural frequencies are obtained by Ritz method. Rapid convergence is observed in this study. The natural frequencies of simply supported power-law FGM sandwich plates are compared with results from different two-dimensional plate theories. Parametric study is performed for varying volume fraction, layer thickness ratios, thickness-length ratios and aspect ratios of the sandwich plates.

  6. A meshfree radial point interpolation method for analysis of functionally graded material (FGM) plates

    Science.gov (United States)

    Dai, K. Y.; Liu, G. R.; Lim, K. M.; Han, X.; Du, S. Y.

    A meshfree model is presented for the static and dynamic analyses of functionally graded material (FGM) plates based on the radial point interpolation method (PIM). In the present method, the mid-plane of an FGM plate is represented by a set of distributed nodes while the material properties in its thickness direction are computed analytically to take into account their continuous variations from one surface to another. Several examples are successfully analyzed for static deflections, natural frequencies and dynamic responses of FGM plates with different volume fraction exponents and boundary conditions. The convergence rate and accuracy are studied and compared with the finite element method (FEM). The effects of the constituent fraction exponent on static deflection as well as natural frequency are also investigated in detail using different FGM models. Based on the current material gradient, it is found that as the volume fraction exponent increases, the mechanical characteristics of the FGM plate approach those of the pure metal plate blended in the FGM.

  7. Geometrically Nonlinear Static Analysis of Edge Cracked Timoshenko Beams Composed of Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Şeref Doğuşcan Akbaş

    2013-01-01

    Full Text Available Geometrically nonlinear static analysis of edge cracked cantilever Timoshenko beams composed of functionally graded material (FGM subjected to a nonfollower transversal point load at the free end of the beam is studied with large displacements and large rotations. Material properties of the beam change in the height direction according to exponential distributions. The cracked beam is modeled as an assembly of two subbeams connected through a massless elastic rotational spring. In the study, the finite element of the beam is constructed by using the total Lagrangian Timoshenko beam element approximation. The nonlinear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. The convergence study is performed for various numbers of finite elements. In the study, the effects of the location of crack, the depth of the crack, and various material distributions on the nonlinear static response of the FGM beam are investigated in detail. Also, the difference between the geometrically linear and nonlinear analysis of edge cracked FGM beam is investigated in detail.

  8. An analysis of surface acoustic wave propagation in a plate of functionally graded materials with a layered model

    Science.gov (United States)

    Gao, Liming; Ji, Wang; Zheng, Zhong; Jianke, Du

    2008-02-01

    In a homogeneous plate, Rayleigh waves will have a symmetric and anti-symmetric mode regarding to the mid-plane with different phase velocities. If plate properties vary along the thickness, or the plate is of functionally graded material (FGM), the symmetry of modes and frequency behavior will be modified, thus producing different features for engineering applications such as amplifying or reducing the velocity and deformation. This kind of effect can also be easily realized by utilizing a layered structure with desired material properties that can produce these effects in terms of velocity and displacements, since Rayleigh waves in a solid with general material property grading schemes are difficult to analyze with known methods. Solutions from layered structures with exponential and polynomial property grading schemes are obtained from the layered model and comparisons with known analytical results are made to validate the method and examine possible applications of such structures in engineering.

  9. Investigation of trapped thickness-twist waves induced by functionally graded piezoelectric material in an inhomogeneous plate

    International Nuclear Information System (INIS)

    Li, Peng; Jin, Feng; Cao, Xiao-Shan

    2013-01-01

    The effect of functional graded piezoelectric materials on the propagation of thickness-twist waves is investigated through equations of the linear theory of piezoelectricity. The elastic and piezoelectric coefficients, dielectric permittivity, and mass density are assumed to change in a linear form but with different graded parameters along the wave propagation direction. We employ the power-series technique to solve the governing differential equations with variable coefficients attributed to the different graded parameters and prove the correction and convergence of this method. As a special case, the functional graded middle layer resulting from piezoelectric damage and material bonding is investigated. Piezoelectric damaged material can facilitate energy trapping, which is impossible in perfect materials. The increase in the damaged length and the reduction in the piezoelectric coefficient decrease the resonance frequency but increase the number of modes. Higher modes of thickness-twist waves appear periodically along the damaged length. Moreover, the displacement of the center of the damaged portion is neither symmetric nor anti-symmetric, unlike the non-graded plate. The conclusions are theoretically and practically significant for wave devices. (paper)

  10. Mechanical and Fatigue Properties of Functionally Graded Aluminium Silicon Alloys =

    Science.gov (United States)

    Maricel, Chirita Georgel

    Many structural components encounter service conditions and, hence, required materials performance, which vary with location within the component. It is well known that abrupt transitions in materials composition and properties within a component often result in sharp local concentrations of stress, whether the stress is internal or applied externally. It is also known that these stress concentrations are greatly reduced if the transition from one material to the other is made gradual. By definition, functionally graded materials are used to produce components featuring engineered gradual transitions in microstructure and/or composition, the presence of which is motivated by functional performance requirements that vary with location within a part. With functionally graded materials, these requirements are met in a manner that optimizes the overall performance of the component. The research on functionally graded materials (FGMs) is encouraged by the need for properties that are unavailable in any single material and the need for graded properties to offset adverse effects of discontinuities for layered materials. Centrifugal casting is a very common method for obtaining functionally graded materials, mainly composite materials or metallic materials which has high differences of density and low solubility on different phases or different materials of the same alloy. The present work is emphasizing the fact that the centrifugal process could be successfully used for obtaining functionally graded materials also for metallic materials (alloys) with moderate solubility and small differences of density of the different phases, as is the case of most aluminum alloys. The first approach of the problem was to isolate the effects of the centrifugal casting technique (the centrifugal pressure effect, the fluid dynamics and the inherent vibration effects) in order to identify the reason of mechanical properties improving. To have a reference for comparison, castings obtained

  11. Wsbnd Cu functionally graded material: Low temperature fabrication and mechanical characterization

    Science.gov (United States)

    Yusefi, Ali; Parvin, Nader; Mohammadi, Hossein

    2018-04-01

    In this study, we fabricated and characterized a Wsbnd Cu functionally graded material (FGM) with 11 layers, including a pure copper layer. Samples were prepared by mixing a mechanically alloyed Nisbnd Mnsbnd Cu powder with W and Cu powders, stacking the powders, pressing the stacked layers, and finally sintering at 1000 °C. The utilization of a Nisbnd Mnsbnd Cu system may reduce the cost but without losing the good sintering behavior and physical and mechanical properties. The composition of the material was analyzed based on scanning electron microscopy images and by energy dispersive X-ray spectroscopy mapping, which indicated that in the presence of Ni and Mn, the Cu atoms could diffuse into the W particles. All of the layers had a very high relative density, thereby indicating their densification and excellent sintering behavior. We also found that the porosity values in the Cu phase remained unchanged at approximately 2.39% across the FGM. Mechanical measurements showed that the hardness (72%), modulus of elasticity (61%), and ultimate tensile strength (58%) increased with the W content across the Wsbnd Cu FGM, whereas the fracture toughness (KIC) varied in the opposite manner (minimum of 4.52 MPa/m0.5).

  12. Analysis of Sigmoid Functionally Graded Material (S-FGM Nanoscale Plates Using the Nonlocal Elasticity Theory

    Directory of Open Access Journals (Sweden)

    Woo-Young Jung

    2013-01-01

    Full Text Available Based on a nonlocal elasticity theory, a model for sigmoid functionally graded material (S-FGM nanoscale plate with first-order shear deformation is studied. The material properties of S-FGM nanoscale plate are assumed to vary according to sigmoid function (two power law distribution of the volume fraction of the constituents. Elastic theory of the sigmoid FGM (S-FGM nanoscale plate is reformulated using the nonlocal differential constitutive relations of Eringen and first-order shear deformation theory. The equations of motion of the nonlocal theories are derived using Hamilton’s principle. The nonlocal elasticity of Eringen has the ability to capture the small scale effect. The solutions of S-FGM nanoscale plate are presented to illustrate the effect of nonlocal theory on bending and vibration response of the S-FGM nanoscale plates. The effects of nonlocal parameters, power law index, aspect ratio, elastic modulus ratio, side-to-thickness ratio, and loading type on bending and vibration response are investigated. Results of the present theory show a good agreement with the reference solutions. These results can be used for evaluating the reliability of size-dependent S-FGM nanoscale plate models developed in the future.

  13. Optimum gradient material for a functionally graded dental implant using metaheuristic algorithms.

    Science.gov (United States)

    Sadollah, Ali; Bahreininejad, Ardeshir

    2011-10-01

    Despite dental implantation being a great success, one of the key issues facing it is a mismatch of mechanical properties between engineered and native biomaterials, which makes osseointegration and bone remodeling problematical. Functionally graded material (FGM) has been proposed as a potential upgrade to some conventional implant materials such as titanium for selection in prosthetic dentistry. The idea of an FGM dental implant is that the property would vary in a certain pattern to match the biomechanical characteristics required at different regions in the hosting bone. However, matching the properties does not necessarily guarantee the best osseointegration and bone remodeling. Little existing research has been reported on developing an optimal design of an FGM dental implant for promoting long-term success. Based upon remodeling results, metaheuristic algorithms such as the genetic algorithms (GAs) and simulated annealing (SA) have been adopted to develop a multi-objective optimal design for FGM implantation design. The results are compared with those in literature. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Porosity-dependent nonlinear forced vibration analysis of functionally graded piezoelectric smart material plates

    Science.gov (United States)

    Qing Wang, Yan; Zu, Jean W.

    2017-10-01

    This work investigates the porosity-dependent nonlinear forced vibrations of functionally graded piezoelectric material (FGPM) plates by using both analytical and numerical methods. The FGPM plates contain porosities owing to the technical issues during the preparation of FGPMs. Two types of porosity distribution, namely, even and uneven distribution, are considered. A modified power law model is adopted to describe the material properties of the porous FGPM plates. Using D’Alembert’s principle, the out-of-plane equation of motion is derived by taking into account the Kármán nonlinear geometrical relations. After that, the Galerkin method is used to discretize the equation of motion, resulting in a set of ordinary differential equations with respect to time. These ordinary differential equations are solved analytically by employing the harmonic balance method. The approximate analytical results are verified by using the adaptive step-size fourth-order Runge-Kutta method. By means of the perturbation technique, the stability of approximate analytical solutions is examined. An interesting nonlinear broadband vibration phenomenon is detected in the FGPM plates with porosities. Nonlinear frequency-response characteristics of the present smart structures are investigated for various system parameters including the porosity type, the porosity volume fraction, the electric potential, the external excitation, the damping and the constituent volume fraction. It is found that these parameters have significant effects on the nonlinear vibration characteristics of porous FGPM plates.

  15. Love waves in functionally graded piezoelectric materials by stiffness matrix method.

    Science.gov (United States)

    Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

    2011-04-01

    A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Development of Functionally Graded Materials for Manufacturing Tools and Dies and Industrial Processing Equipment

    Energy Technology Data Exchange (ETDEWEB)

    Lherbier, Louis, W.; Novotnak, David, J.; Herling, Darrell, R.; Sears, James, W.

    2009-03-23

    Hot forming processes such as forging, die casting and glass forming require tooling that is subjected to high temperatures during the manufacturing of components. Current tooling is adversely affected by prolonged exposure at high temperatures. Initial studies were conducted to determine the root cause of tool failures in a number of applications. Results show that tool failures vary and depend on the operating environment under which they are used. Major root cause failures include (1) thermal softening, (2) fatigue and (3) tool erosion, all of which are affected by process boundary conditions such as lubrication, cooling, process speed, etc. While thermal management is a key to addressing tooling failures, it was clear that new tooling materials with superior high temperature strength could provide improved manufacturing efficiencies. These efficiencies are based on the use of functionally graded materials (FGM), a new subset of hybrid tools with customizable properties that can be fabricated using advanced powder metallurgy manufacturing technologies. Modeling studies of the various hot forming processes helped identify the effect of key variables such as stress, temperature and cooling rate and aid in the selection of tooling materials for specific applications. To address the problem of high temperature strength, several advanced powder metallurgy nickel and cobalt based alloys were selected for evaluation. These materials were manufactured into tooling using two relatively new consolidation processes. One process involved laser powder deposition (LPD) and the second involved a solid state dynamic powder consolidation (SSDPC) process. These processes made possible functionally graded materials (FGM) that resulted in shaped tooling that was monolithic, bi-metallic or substrate coated. Manufacturing of tooling with these processes was determined to be robust and consistent for a variety of materials. Prototype and production testing of FGM tooling showed the

  17. Analysis of Dynamic Fracture Parameters in Functionally Graded Material Plates with Cracks by Graded Finite Element Method and Virtual Crack Closure Technique

    Directory of Open Access Journals (Sweden)

    Li Ming Zhou

    2016-01-01

    Full Text Available Based on the finite element software ABAQUS and graded element method, we developed a dummy node fracture element, wrote the user subroutines UMAT and UEL, and solved the energy release rate component of functionally graded material (FGM plates with cracks. An interface element tailored for the virtual crack closure technique (VCCT was applied. Fixed cracks and moving cracks under dynamic loads were simulated. The results were compared to other VCCT-based analyses. With the implementation of a crack speed function within the element, it can be easily expanded to the cases of varying crack velocities, without convergence difficulty for all cases. Neither singular element nor collapsed element was required. Therefore, due to its simplicity, the VCCT interface element is a potential tool for engineers to conduct dynamic fracture analysis in conjunction with commercial finite element analysis codes.

  18. Size-Dependent Bending, Buckling and Free Vibration Analyses of Microscale Functionally Graded Mindlin Plates Based on the Strain Gradient Elasticity Theory

    Directory of Open Access Journals (Sweden)

    R. Ansari

    Full Text Available Abstract In this paper, a size-dependent microscale plate model is developed to describe the bending, buckling and free vibration behaviors of microplates made of functionally graded materials (FGMs. The size effects are captured based on the modified strain gradient theory (MSGT, and the formulation of the paper is on the basis of Mindlin plate theory. The presented model accommodates the models based upon the classical theory (CT and the modified couple stress theory (MCST if all or two scale parameters are set to zero, respectively. By using Hamilton's principle, the governing equations and related boundary conditions are derived. The bending, buckling and free vibration problems are considered and are solved through the generalized differential quadrature (GDQ method. A detailed parametric and comparative study is conducted to evaluate the effects of length scale parameter, material gradient index and aspect ratio predicted by the CT, MCST and MSGT on the deflection, critical buckling load and first natural frequency of the microplate. The numerical results indicate that the model developed herein is significantly size-dependent when the thickness of the microplate is on the order of the material scale parameters.

  19. Stochastic Finite element analysis of the free vibration of functionally graded material plates

    Science.gov (United States)

    Shaker, Afeefa; Abdelrahman, Wael; Tawfik, Mohammad; Sadek, Edward

    2008-02-01

    The superior properties of functionally graded materials (FGM) are usually accompanied by randomness in their properties due to difficulties in tailoring the gradients during manufacturing processes. Using the stochastic finite element method (SFEM) proved to be a powerful tool in studying the sensitivity of the static response of FGM plates to uncertainties in their material properties. This tool is yet to be used in studying free vibration of FGM plates. The aim of this work is to use both a First Order Reliability Method (FORM) and the Second Order Reliability Method (SORM), combined with a nine-noded isoparametric Lagrangian element based on the third order shear deformation theory to investigate sensitivity of the fundamental frequency of FGM plates to material uncertainties. These include the effect of uncertainties on both the metal and ceramic constituents. The basic random variables include ceramic and metal Young’s modulus and Poisson’s ratio, their densities and ceramic volume fraction. The developed code utilizes MATLAB capabilities to derive the derivatives of the stiffness and mass matrices symbolically with a considerable reduction in calculation time. Calculating the eigenvectors at the mean values of the variables proves to be a reasonable simplification which significantly increases solution speed. The stochastic finite element code is validated using available data in the literature, in addition to comparisons with results of the well-established Monte Carlo simulation technique with importance sampling. Results show that SORM is an excellent rapid tool in the stochastic analysis of free vibration of FGM plates, when compared to the slower Monte Carlo simulation techniques.

  20. DEVELOPING SIGNS AND SONGS MATERIALS DEALING WITH THE 2013 CURRICULUM FOR THE SEVENTH GRADE STUDENTS IN MTSN BALANG-BALANG

    Directory of Open Access Journals (Sweden)

    Mardiana

    2016-04-01

    Full Text Available This research aimed to develop Signs and Songs Materials based on 2013 curriculum for the Seventh Grade Student at MTsN. BalangBalang, Gowa. It was Research and Development (R&D applied ADDIE model standing for Analysis, Design, Develop, Implement, and Evaluate. The procedures were; 1 analyzing materials needed by students; 2designing the blueprint; 3 developing the materials through the syllabus of 2013 Curriculum; 4 implementing the product (try-out product; and 5 evaluating the product. The product was tried out to the seventh grade students at MTsN Balang-balang. Type of data obtained in this study was qualitative. The instruments used in this study were questionnaire and rubrics for teacher and expert. Then, the teacher and expert were involved in order to validate the product. They validated three systematic aspects of the product, namely; the organization of the Materials, English Teaching strategies or method, and the content of the materials. Finally, based on the teacher and expert judgment as well as try-out design result, it was found that the developed materials were applicable to be taught for the Seventh Grade of Junior High School as additional learning and teaching materials which help both students and teachers in learning process based on 2013 Curriculum.

  1. ‘Big Books’ as Mother Tongue-Based Instructional Materials in Bicol for Grade One Pupils

    Directory of Open Access Journals (Sweden)

    Magdalena M. Ocbian,

    2015-11-01

    Full Text Available Language experts claim that it is easier for pupils to learn when the mother tongue is used in the teaching learning process including the learning of a second language. This study determined the reading comprehension level of Grade I pupils in Bulusan Central School for school year 2013-2014 as input in developing big books written in the vernacular that can be used as reading materials for Grade 1 pupils. Results of the evaluation revealed that they belong to the frustration and instructional levels in the literal skill; mostly are frustration readers along interpretative and evaluative skills; but are independent readers along applied skills; hence, they have low level of reading comprehension. Based on the result of the study, three big books as MTB-MLE instructional materials in Bicol were produced to develop or enhance Grade 1 pupils’ reading comprehension. Teaching guides were likewise developed.

  2. Thermal stresses in functionally graded materials caused by a laser thermal shock

    Science.gov (United States)

    Elperin, T.; Rudin, G.

    Mathematical simulation of a thermal shock method for reliability testing of functionally graded material (FGM) is performed with the end to determine operating parameters of the testing device (power of a laser, laser beam radius, duration of heating) and to investigate the effect of the composition of FGM on a magnitude of thermal stresses in a coating. An analytical method for solution of the thermal elasticity problem is developed whereby the approach of a multilayer plate is used for determining temperature and thermal stresses distributions in a coating. We considered the limiting case of the obtained solution when the thickness of a layer is infinitesimally small and the number of layers tends to infinity. This procedure allowed us to obtain the thermal stresses distribution in a FGM coating. The results for the FGM coating composed of WC (tungsten carbide) ceramics and HS-steel are presented. It is showed that variation of the volume content of ceramics strongly affects thermal stresses in a coating and they decrease significantly in the case of the uniform spatial distribution of ceramics.

  3. The First Cycle of Developing Teaching Materials for Fractions in Grade Five Using Realistic Mathematics Education

    Directory of Open Access Journals (Sweden)

    Hongki Julie

    2013-07-01

    Full Text Available There are three questions that will be answered in this study, namely (1 what are the contexts that can be used to introduce the meaning of multiplication of two fractions and to find the result of multiplying two fractions, (2 how to use these contexts to help students construct the understanding of the meaning of multiplication of two fractions and find the result of multiplying two fractions, and (3 what is the impact of the teaching-learning process that has been designed by researchers on the process of students' knowledge construction. Learning approach which was used in developing teaching materials about fractions is realistic mathematics approach. Lesson plan was created for fifth grade elementary school students. The type of research used is developmental research. According to Gravemeijer and Cobb (in Akker, Gravemeijer, McKeney, and Nieveen, 2006 there are three phases in development research, namely (1 preparation of the trial design, (2 the trial design, and (3 retrospective analysis. This paper presents the results of the first cycle of three cycles that have been planned.Key words: fractions, realistic mathematics education, design research. DOI: http://dx.doi.org/10.22342/jme.4.2.415.172-187

  4. Computer Assisted Educational Material Preparation for Fourth Grade Primary School Students' English Language Class in Teaching Numbers

    Science.gov (United States)

    Yüzen, Abdulkadir; Karamete, Aysen

    2016-01-01

    In this study, using ADDIE instructional design model, it is aimed to prepare English language educational material for 4th grade primary students to teach them numbers. At the same time, ARCS model of motivation's attention, relevance and satisfaction phases are also taken into consideration. This study also comprises of Design Based Research…

  5. Mitigating the Effects of the Space Radiation Environment: A Novel Approach of Using Graded-Z Materials

    Science.gov (United States)

    Atwell, William; Rojdev, Kristina; Aghara, Sukesh; Sriprisan, Sirikul

    2013-01-01

    In this paper we present a novel space radiation shielding approach using various material lay-ups, called "Graded-Z" shielding, which could optimize cost, weight, and safety while mitigating the radiation exposures from the trapped radiation and solar proton environments, as well as the galactic cosmic radiation (GCR) environment, to humans and electronics. In addition, a validation and verification (V&V) was performed using two different high energy particle transport/dose codes (MCNPX & HZETRN). Inherently, we know that materials having high-hydrogen content are very good space radiation shielding materials. Graded-Z material lay-ups are very good trapped electron mitigators for medium earth orbit (MEO) and geostationary earth orbit (GEO). In addition, secondary particles, namely neutrons, are produced as the primary particles penetrate a spacecraft, which can have deleterious effects to both humans and electronics. The use of "dopants," such as beryllium, boron, and lithium, impregnated in other shielding materials provides a means of absorbing the secondary neutrons. Several examples of optimized Graded-Z shielding layups that include the use of composite materials are presented and discussed in detail. This parametric shielding study is an extension of some earlier pioneering work we (William Atwell and Kristina Rojdev) performed in 20041 and 20092.

  6. Strand I: Physical Health Nutrition. Health Curriculum Materials. Grades 7-9.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    GRADES OR AGES: Grades 7, 8, and 9. SUBJECT MATTER: Physical health and nutrition. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into five sections: nutritional states, adequate diet, nutrition in adolescence, the achievement and maintainance of correct weight, and environmental factors which affect nutritional health. The publication…

  7. A Novel Higher-Order Shear and Normal Deformable Plate Theory for the Static, Free Vibration and Buckling Analysis of Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    Shi-Chao Yi

    2017-01-01

    Full Text Available Closed-form solution of a special higher-order shear and normal deformable plate theory is presented for the static situations, natural frequencies, and buckling responses of simple supported functionally graded materials plates (FGMs. Distinguished from the usual theories, the uniqueness is the differentia of the new plate theory. Each individual FGM plate has special characteristics, such as material properties and length-thickness ratio. These distinctive attributes determine a set of orthogonal polynomials, and then the polynomials can form an exclusive plate theory. Thus, the novel plate theory has two merits: one is the orthogonality, where the majority of the coefficients of the equations derived from Hamilton’s principle are zero; the other is the flexibility, where the order of the plate theory can be arbitrarily set. Numerical examples with different shapes of plates are presented and the achieved results are compared with the reference solutions available in the literature. Several aspects of the model involving relevant parameters, length-to-thickness, stiffness ratios, and so forth affected by static and dynamic situations are elaborate analyzed in detail. As a consequence, the applicability and the effectiveness of the present method for accurately computing deflection, stresses, natural frequencies, and buckling response of various FGM plates are demonstrated.

  8. S1-ZGV Modes of a Linear and Nonlinear Profile for Functionally Graded Material Using Power Series Technique

    Directory of Open Access Journals (Sweden)

    M. Zagrouba

    2014-01-01

    Full Text Available The present work deals with functionally graded materials (FGM isotropic plates in the neighborhood of the first-order symmetric zero group velocity (S1-ZGV point. The mechanical properties of functionally graded material (FGM are assumed to vary continuously through the thickness of the plate and obey a power law of the volume fraction of the constituents. Governing equations for the problem are derived, and the power series technique (PST is employed to solve the recursive equations. The impact of the FGM basic materials properties on S1-ZGV frequency of FGM plate is investigated. Numerical results show that S1-ZGV frequency is comparatively more sensitive to the shear modulus. The gradient coefficient p does not affect the linear dependence of ZGV frequency fo as function of cut-off frequency fc; only the slope is slightly varied.

  9. Convective–radiative radial fins with convective base heating and convective–radiative tip cooling: Homogeneous and functionally graded materials

    International Nuclear Information System (INIS)

    Aziz, A.; Torabi, Mohsen; Zhang, Kaili

    2013-01-01

    Highlights: • Convective–radiative radial fins with base convective heating were analyzed. • Homogeneous material and functionally graded material fins were investigated. • Fin efficiency and the effects of dimensionless parameters in fins were analyzed. - Abstract: This paper studies a radial fin of uniform thickness with convective heating at the base and convective–radiative cooling at the tip. The fin is assumed to experience uniform internal heat generation. The exposed surfaces of the fin lose heat by simultaneous convection and radiation to the surroundings. Two types of fin materials are investigated: homogeneous material and functionally graded material (FGM). For the homogeneous material, the thermal conductivity is assumed to be a linear function of temperature, while for the FGM fin the thermal conductivity is modeled as a linear function of the dimensionless radial coordinate. The analysis is conducted using the differential transformation method (DTM). The accuracy of DTM is verified by comparing the results for the simplified versions of the present model with an exact analytical solution derived here. Once the accuracy of DTM is authenticated, the method is used to generate results for the general problem formulated here. These results illustrate the effects of various dimensionless parameters on the thermal performance of homogeneous material fins and FGM fins

  10. Impact of interfacial imperfection on transverse wave in a functionally graded piezoelectric material structure with corrugated boundaries

    Science.gov (United States)

    Kumar Singh, Abhishek; Kumar, Santan; Kumari, Richa

    2018-03-01

    The propagation behavior of Love-type wave in a corrugated functionally graded piezoelectric material layered structure has been taken into account. Concretely, the layered structure incorporates a corrugated functionally graded piezoelectric material layer imperfectly bonded to a functionally graded piezoelectric material half-space. An analytical treatment has been employed to determine the dispersion relation for both cases of electrically open condition and electrically short condition. The phase velocity of the Love-type wave has been computed numerically and its dependence on the wave number has been depicted graphically for a specific type of corrugated boundary surfaces for both said conditions. The crux of the study lies in the fact that the imperfect bonding of the interface, the corrugated boundaries present in the layer, and the material properties of the layer and the half-space strongly influence the phase velocity of the Love-type wave. It can be remarkably noted that the imperfect bonding of the interface reduces the phase velocity of the Love-type wave significantly. As a special case of the problem, it is noticed that the procured dispersion relation for both cases of electrically open and electrically short conditions is in accordance with the classical Love wave equation.

  11. Graded approach for establishment of QA requirements for Type B packaging of radioactive material

    International Nuclear Information System (INIS)

    Fabian, R.R.; Woodruff, K.C.

    1988-01-01

    A study that was conducted by the Nuclear Regulatory Commission for the U.S. Congress to assess the effectiveness of quality assurance (QA) activities has demonstrated a need to modify and improve the application of QA requirements for the nuclear industry. As a result, the packaging community, along with the nuclear industry as a whole, has taken action to increase the efficacy of the QA function. The results of the study indicate that a graded approach for establishing QA requirements is the preferred method. The essence of the graded approach is the establishment of applicable QA requirements to an extent consistent with the importance to safety of an item, component, system, or activity. This paper describes the process that is used to develop the graded approach for QA requirements pertaining to Type B packaging

  12. Elasto-plastic damage analysis of functionally graded material disks subjected to thermal shock and thermal cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Myung; Toi, Yutaka [Tokyo Univ. (Japan). Inst. of Industrial Science

    2001-03-01

    The elasto-plastic damage behaviors of functionally graded materials (FGM) subjected to thermal loading are analyzed by the finite element method using continuum damage mechanics. The Lemaitre's damage model is employed to analyze the damage behavior of a FGM disk subjected to thermal shock and a FGM coating subjected to thermal cycle. The effect of FGM on the thermal damage is discussed through some numerical examples for industrial materials. Numerical results show the validity of the present method for the evaluation and the development of new FGM. (author)

  13. The Grading Entropy-based Criteria for Structural Stability of Granular Materials and Filters

    Directory of Open Access Journals (Sweden)

    Janos Lőrincz

    2015-05-01

    Full Text Available This paper deals with three grading entropy-based rules that describe different soil structure stability phenomena: an internal stability rule, a filtering rule and a segregation rule. These rules are elaborated on the basis of a large amount of laboratory testing and from existing knowledge in the field. Use is made of the theory of grading entropy to derive parameters which incorporate all of the information of the grading curve into a pair of entropy-based parameters that allow soils with common behaviours to be grouped into domains on an entropy diagram. Applications of the derived entropy-based rules are presented by examining the reason of a dam failure, by testing against the existing filter rules from the literature, and by giving some examples for the design of non-segregating grading curves (discrete particle size distributions by dry weight. A physical basis for the internal stability rule is established, wherein the higher values of base entropy required for granular stability are shown to reflect the closeness between the mean and maximum grain diameters, which explains how there are sufficient coarser grains to achieve a stable grain skeleton.

  14. Functionally Graded Thermoelectric Material though One Step Band Gap and Dopant Engineering

    DEFF Research Database (Denmark)

    Jensen, Ellen Marie; Borup, Kasper Andersen; Cederkrantz, Daniel

    gradients. It has previously been shown that a large functionally graded thermoelectric single crystal can be synthesized by the Czochralski method (1). Utilizing element gradients inherent to the Czochralski process we have synthesized a Ge1-xSix:B crystal with a continuously varying x, band gap...

  15. Screening of various low-grade biomass materials for low temperature gasification: Method development and application

    DEFF Research Database (Denmark)

    Thomsen, Tobias Pape; Ravenni, Giulia; Holm, Jens Kai

    2015-01-01

    method and the subsequent use of the method to identify promising e but currently unproven, low-grade biomass resources for conversion in Pyroneer systems. The technical assessment is conducted by comparing the results from a series of physical-mechanical and thermochemical experiments to a set of proven...

  16. Development of Integrated Natural Science Teaching Materials Webbed Type with Applying Discourse Analysis on Students Grade VIII in Physics Class

    Science.gov (United States)

    Sukariasih, Luh

    2017-05-01

    This study aims to produce teaching materials integrated natural science (IPA) webbed type of handout types are eligible for use in integrated science teaching. This type of research IS a kind of research and development / Research and Development (R & D) with reference to the 4D development model that is (define, design, develop, and disseminate). Data analysis techniques used to process data from the results of the assessment by the validator expert, and the results of the assessment by teachers and learners while testing is limited (12 students of class VIII SMPN 10 Kendari) using quantitative descriptive data analysis techniques disclosed in the distribution of scores on the scale of five categories grading scale that has been determined. The results of due diligence material gain votes validator material in the category of “very good” and “good”, of the data generated in the feasibility test presentation obtained the category of “good” and “excellent”, from the data generated in the feasibility of graphic test obtained the category of “very good “and” good “, as well as of the data generated in the test the feasibility of using words and language obtained the category of“very good “and” good “, so with qualifications gained the teaching materials IPA integrated type webbed by applying discourse analysis on the theme of energy and food for Junior High School (SMP) grade VIII suitable as teaching materials. In limited testing, data generated in response to a science teacher at SMPN 10 Kendari to product instructional materials as “excellent”, and from the data generated while testing is limited by the 12 students of class VIII SMPN 10 Kendari are more students who score indicates category “very good”, so that the qualification obtained by the natural science (IPA) teaching material integrated type webbed by applying discourse analysis on the theme of energy and food for SMP / class VIII fit for use as teaching material.

  17. The Effect of Material Property on the Critical Velocity of Randomly Excited Nonlinear Axially Travelling Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    M. Abedi

    Full Text Available Abstract In this paper, the critical axial speeds of three types of sigmoid, power law and exponential law functionally graded plates for both isotropic and orthotropic cases are obtained via a completely analytic method. The plates are subjected to lateral white noise excitation and show evidence of large deformations. Due to randomness, the conventional deterministic methods fail and a statistical approach must be selected. Here, the probability density function is evaluated analytically for prescribed plates and used to investigate the critical axial velocity of them. Specifically the effect of in-plane forces, mean value of lateral load and the material property on the critical axial speed are studied and discussed for both isotropic and orthotropic functionally graded plates. Since the governing equation is transformed to a non dimensional format, the results can be used for a wide range of plate dimensions. It is shown that the material heterogeneity palys an essential and significant role in increasing or decreasing the critical speed of both isotropic and orthotropic functionally graded plates.

  18. Analytical solution for wave propagation through a graded index interface between a right-handed and a left-handed material.

    Science.gov (United States)

    Dalarsson, Mariana; Tassin, Philippe

    2009-04-13

    We have investigated the transmission and reflection properties of structures incorporating left-handed materials with graded index of refraction. We present an exact analytical solution to Helmholtz' equation for a graded index profile changing according to a hyperbolic tangent function along the propagation direction. We derive expressions for the field intensity along the graded index structure, and we show excellent agreement between the analytical solution and the corresponding results obtained by accurate numerical simulations. Our model straightforwardly allows for arbitrary spectral dispersion.

  19. Analytical solution for wave propagation through a graded index interface between a right-handed and a left-handed material

    OpenAIRE

    Dalarsson, Mariana; Tassin, Philippe

    2012-01-01

    We have investigated the transmission and reflection properties of structures incorporating left-handed materials with graded index of refraction. We present an exact analytical solution to Helmholtz' equation for a graded index profile changing according to a hyperbolic tangent function along the propagation direction. We derive expressions for the field intensity along the graded index structure, and we show excellent agreement between the analytical solution and the corresponding results o...

  20. Embedding Designed Deformation: towards the computational design of graded material components

    DEFF Research Database (Denmark)

    Nicholas, Paul

    2011-01-01

    Recognising that the process of making materials affords opportunities not available when using existing natural or off-the-shelf materials, the focus of this paper is upon abstraction strategies by which the mechanical properties of composite materials might be engaged within digital architectur...

  1. Analysis of elastic field in functionally graded material beams with square cross-section

    Science.gov (United States)

    Agrawal, Manish; Ahsan, Mohammad Al; Afsar Ali, Md.

    2017-12-01

    A square and simply supported functionally graded beam of medium thickness, subjected to a point load, has been investigated. Young's modulus of elasticity is assumed to vary following linear, exponential and power function along the thickness direction. Numerical Results show the variation of flexural stress and position of neutral axis with the change of the ratio of Young's modulus of elasticity of the top and bottom surfaces.

  2. Study of one-dimensional nanolayered graded photonic crystal consisting of birefringent and dielectric materials

    Science.gov (United States)

    Kumar, Rajeev; Kumar, Dhananjay; Kushwaha, Angad S.; Srivastava, S. K.

    2018-02-01

    In the present paper, we have studied a comparison between dielectric-dielectric photonic crystal (PhC) and birefringent-dielectric PhC structure with, and without, gradation in the thickness of the layers of the proposed structure. Graded birefringent-dielectric PhC has a linear change in the thickness of the layers. With the help of the transfer matrix method, the proposed structures have been extensively investigated. It is found that photonic band gap (PBG) width and omnidirectional reflection band width has been widely enhanced, in graded birefringent-dielectric PhC structure as compared to the non-graded birefringent-dielectric PhC structure, for both TE and TM polarizations. We have also found that the gradation in the thickness of the birefringent layer is more effective, as compare the gradation in the thickness of the dielectric layer, for enhancement of reflection band width. The results obtained are quite good and thus, it may be widely used as broad band optical and omnidirectional reflector.

  3. Application of the Reverberation-Ray Matrix to the Non-Fourier Heat Conduction in Functionally Graded Materials

    Science.gov (United States)

    Zhou, Feng-xi

    2016-02-01

    The method of the reverberation-ray matrix has been developed and successfully applied to analyse the wave propagation in a multibranched framed structure or in a layered medium. However, the method is confined to the case of mechanical loads applied at the medium until now. This paper aims to extend the formulation of the reverberation-ray matrix to cases of thermal propagation and diffusion. The thermal response in functionally graded materials (FGM) with the non-Fourier heat conduction model is analysed. In the present work, it is assumed that the material properties of an FG plate vary only in the thickness direction by following the power law function. The effect of non-Fourier and material inhomogeneity in the plate subjected to a periodic thermal disturbance is investigated. The present approach is validated by comparing it with the solutions obtained by other methods.

  4. METHOD OF DIMENSIONALITY REDUCTION IN CONTACT MECHANICS AND FRICTION: A USER'S HANDBOOK. II. POWER-LAW GRADED MATERIALS

    Directory of Open Access Journals (Sweden)

    Markus Hess

    2016-12-01

    Full Text Available Until recently, the only way of solving contact problems was to applythree-dimensional contact theories. However, this presupposes higher mathematical and numerical knowledge, which usually only research groups possess. This has changed drastically with the development of the method of dimensionality reduction (MDR, which allows every practically oriented engineer an access to the solution of contact problems. The simple and contact-type dependent rules are summarized in the first part of the user manual; they require contacts between elastically homogeneous materials. The present paper forms the second part of the user handbook and is dedicated to the solution of contact problems between power-law graded materials. All the MDR-rules are listed with which normal, tangential and adhesive contacts between such high-performance materials can be calculated in a simple manner.

  5. Suitability of Different Food Grade Materials for the Encapsulation of Some Functional Foods Well Reported for Their Advantages and Susceptibility.

    Science.gov (United States)

    Wani, Touseef Ahmed; Shah, Adil Gani; Wani, Sajad Mohd; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad; Nissar, Nazia; Shagoo, Mudasir Ahmad

    2016-11-17

    Functional foods find a very important place in the modern era, where different types of cancer, diabetes, cardiovascular diseases, etc. are on a high. Irrespective of the abundance of bioactive components in different fruits and vegetables, their low solubility in aqueous solution, vulnerability to destruction in different environmental and gastrointestinal conditions and a low intestinal absorption becomes a concern. Because it is quite difficult to commercialize non food materials for the food encapsulation purposes due to their safety concerns in the human body, scientists in the recent times have come up with the idea of encapsulating the different bioactive components in different food grade materials that are able to safeguard these bioactive components against the different environmental and gastrointestinal conditions and ensure their safe and targeted delivery at their absorption sites. Different food grade encapsulation materials including various oligosaccharides, polysaccharides (starch, cyclodextrins, alginates, chitosan, gum arabic, and carboxymethyl cellulose) and proteins and their suitability for encapsulating various bioactive components like flavonoids (catechins, rutin, curcumin, hesperetin, and vanillin), nonflavonoids (resveratrol), carotenoids (β-carotene, lycopene, and lutein), and fatty acids (fish oil, flaxseed oil, and olive oil) of high medical and nutritional value are reviewed here.

  6. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Among the...

  7. Advanced Thermal Protection Systems (ATPS), Aerospace Grade Carbon Bonded Carbon Fiber Material, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Carbon bonded carbon fiber (CBCF) insulating material is the basis for several highly successful NASA developed thermal protection systems (TPS). Included among...

  8. Exposure of W-TiC/Cu Functionally Graded Materials in the Edge Plasma of HT-7 Tokamak

    International Nuclear Information System (INIS)

    Liu Yang; Zhu Dahuan; Chen Junling; Yan Rong; Zhou Zhangjian

    2012-01-01

    Six-layered W-TiC/Cu functionally graded materials were fabricated by resistance sintering under ultra-high pressure and exposed in the edge plasma of HT-7 tokamak. Microstructure morphologies show that the TiC particles distribute homogeneously in the W matrix, strengthening the grain boundary, while gradient layers provide a good compositional transition from W-TiC to Cu. After about 360 shots in the HT-7 tokamak, clear surface modification can be observed after plasma exposure, and the addition of nano TiC particles is beneficial to the improvement of plasma loads resistance of W.

  9. THE INFLUENCE OF MATERIAL-TECHNICAL CONDITIONS ON SPEED MEASUREMENT OF FEMALE STUDENTS IN LOWER PRIMARY SCHOOL GRADES

    Directory of Open Access Journals (Sweden)

    Živorad Marković

    2011-03-01

    Full Text Available The goal of this research was to determine the influence of material-technical conditions on speed evaluation of female students in lower primery school grades, in the conditions of most frequent floors (grass, asphalt, parquet. The research was realized in primary school “Jovan Jovanovic Zmaj” in Svilajnac, republic of Serbia in the first term of 2009/2010 school year. The sample consisted of 45 female students in fourth grade of primary school. The speed of female students was evaluated by the use of two standardized movement tasks: a 30 meter running from high start and shuttle running 3x10 meters. For the evaluation of the results the following methods were used: descriptive statistics, multivariant analysis of the variance, discriminative analysis and univariant analysis of the variance. The results indicate statistically significant differences of the results of female students for both researched variables in relation to the floor. The results enable more adequate planning and content realization of physical education in lower grades of primary school.

  10. Next Generation Solar Cells Based on Graded Bandgap Device Structures Utilising Rod-Type Nano-Materials

    Directory of Open Access Journals (Sweden)

    Imyhamy M. Dharmadasa

    2015-06-01

    Full Text Available Current solar cells under research and development utilise mainly one absorber layer limiting the photon harvesting capabilities. In order to develop next generation solar cells, research should move towards effective photon harvesting methods utilising low-cost solar energy materials. This will lead to reduce the $W−1 figure for direct solar energy conversion to electrical energy. In this work, a graded bandgap solar cell has been designed to absorb all photons from the UV, visible and IR regions. In addition, impurity PV effect and impact ionisation have been incorporated to enhance charge carrier creation within the same device. This new design has been experimentally tested using the most researched MOCVD grown GaAs/AlGaAs system, in order to confirm its validity. Devices with high Voc ~ 1175 mV and the highest possible FF ~ (0.85–0.87 have been produced, increasing the conversion efficiency to ~20% within only two growth runs. These devices were also experimentally tested for the existence of impurity PV effect and impact ionisation. The devices are PV active in complete darkness producing over 800 mV, Voc indicating the harvesting of IR radiation from the surroundings through impurity PV effect. The quantum efficiency measurements show over 140% signal confirming the contribution to PV action from impact ionisation. Since the concept is successfully proven, the low-cost and scalable electrodeposited semiconducting layers are used to produce graded bandgap solar cell structures. The utilisation of nano- and micro-rod type materials in graded bandgap devices are also presented and discussed in this paper. Preliminary work on glass/FTO/n-ZnS/n-CdS/n-CdTe/Au graded bandgap devices show 10%–12% efficient devices indicating extremely high Jsc values ~48 mA·cm−2, showing the high potential of these devices in achieving higher efficiencies. The detailed results on these low-cost and novel graded bandgap devices are presented in a separate

  11. Analysis of Subject Material and Material Presentation of 7th Grade Mathematics Books Viewed from Mathematics Learning Objectives

    Directory of Open Access Journals (Sweden)

    Anindya Gita Maharani

    2017-03-01

    Full Text Available Penelitian ini bertujuan untuk mengetahui bagaimanakah kesesuaian materi dan penyajian buku pelajaran yang diterbikan oleh Erlangga ditinjau dari tujuan pembelajaran Matematika. Objek penelitian ini adalah buku teks pelajaran Matematika SMP yang digunakan di sekolah yaitu Matematika SMP kurikulum 2013 kelas VII semester II karangan M.Cholik Adinawan dan Sugijono yang diterbitkan oleh Erlangga tahun 2013. Buku Siswa terbitan Depdiknas tahun 2014 digunakan sebagai data pembanding. Data diperoleh dengan metode dokumentasi dan observasi. Analisis data yang digunakan adalah kajian isi melalui penskoran dengan menelah dan membandingkan kesesuaian materi dan penyajian buku teks ditinjau dari tujuan pembelajaran Matematika. Hasil penelitian menunjukkan bahwa: (1 Materi pada buku teks pelajaran Matematika SMP kelas VII terbitan Erlangga yang digunakan dalam kegiatan belajar mengajar di sekolah-sekolah di Kabupaten Pacitan secara umum sudah sesuai dengan tujuan pembelajaran Matematika. (2 Penyajian pada buku teks pelajaran Matematika SMP kelas VII terbitan Erlangga yang digunakan dalam kegiatan belajar mengajar di sekolah-sekolah di Kabupaten Pacitan secara umum sudah sesuai dengan tujuan pembelajaran Matematika.   The purpose of this research is to determine how the suitability of the material and the presentation of textbooks published by Erlangga terms of learning objectives Mathematics. The object of this research is a mathematics textbooks used in junior high school curriculum 2013 is class VII 2013 second semester essay M.Cholik Adinawan and Sugijono published by Erlangga 2013. Student Book published by the National Education Ministry in 2014 was used as comparative data. Data obtained by the method of documentation and observation. Analysis of the data used is the study of the contents through the scoring with a predict and compare the suitability of the material and the presentation of textbooks in terms of learning objectives Mathematics. The

  12. FGM (Functionally Graded Material) Thermal Barrier Coatings for Hypersonic Structures - Design and Thermal Structural Analysis

    National Research Council Canada - National Science Library

    Ho, Sook-Ying; Kotousov, Andrei; Nguyen, Phuc; Harding, Steven; Codrington, John; Tsukamoto, Hideaki

    2007-01-01

    .... It utilizes a pressurized spray gun to spray a slurry mixture of the powdered coating material suspended in a liquid solution directly onto a substrate surface followed by sintering using an oxyacetylene torch...

  13. Micromechanical modelling of functionally graded W-Cu materials for divertor plate components in a fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gasik, M.M. [Helsinki Univ. of Technol. (Finland); Ueda, S.

    1999-10-01

    Thermonuclear fusion process implementation has many materials problems and one of them is related to removal of impurities from plasma. In the International thermonuclear experimental reactor (ITER), a divertor concept has been incorporated for this purpose. In this work, the development of a micromechanical model for FGM is presented and its application to thermal-elasto-plastic analysis is discussed for the case of W-Cu FGM for ITER divertor plates. The model allows the prediction of basic properties of 3-D FGM, computations of thermal stresses, and, in some limits, it may be used for pre-design evaluation of dynamic strain/stress distribution and inelastic behaviour. The model is found to be very useful at the first stages of graded materials design and computation of properties in the nodal points for more detailed numerical analysis. (orig.) 10 refs.

  14. Optical and spectroscopic characterizations of Algerian silica raw material to predict high quality solar-grade silicon

    Science.gov (United States)

    Kheloufi, A.; Bobocioiu, E.; Kerkar, F.; Kefaifi, A.; Anas, S.; Medjahed, S. A.; Belkacem, Y.; Keffous, A.

    2017-03-01

    We assess the potential use as raw material for photovoltaics of Algerian silica samples from the quartz veins of the Tirek deposit and quartz sandstones of the Ain Barda deposit. With 97-98% purity, they all require enrichment before their industrial utilization. Acid leaching and gravimetric separation are used to remove the impurities at the grain boundaries and within the crystal lattice. We obtain course, middle, and fine products. The acid leaching process and the gravimetric separation increase the content of SiO2 up to 99.68%; the residue concentration of iron, alumina and zirconium is decreased to 70, 72 and 58 ppm respectively. These values are in agreement with requirements for silica as raw material destined for solar-grade silicon production.

  15. Three-Dimensional Elasticity Solutions for Sound Radiation of Functionally Graded Materials Plates considering State Space Method

    Directory of Open Access Journals (Sweden)

    Tieliang Yang

    2016-01-01

    Full Text Available This paper presents an analytical study for sound radiation of functionally graded materials (FGM plate based on the three-dimensional theory of elasticity. The FGM plate is a mixture of metal and ceramic, and its material properties are assumed to have smooth and continuous variation in the thickness direction according to a power-law distribution in terms of volume fractions of the constituents. Based on the three-dimensional theory of elasticity and state space method, the governing equations with variable coefficients of the FGM plate are derived. The sound radiation of the vibration plate is calculated with Rayleigh integral. Comparisons of the present results with those of solutions in the available literature are made and good agreements are achieved. Finally, some parametric studies are carried out to investigate the sound radiation properties of FGM plates.

  16. The Effectiveness of E-Writing Materials to Teach Writing Skill for Second Grade Students of Junior High School

    Directory of Open Access Journals (Sweden)

    Hanif Maulaniam Sholah

    2017-01-01

    Full Text Available The Practice of writing is very important for students. The more students practice, the more their skill improves. To make students eager in writing either paragraph or essay, they need a media which can attract them to write over and over. Recently, the media provided by school is only handbook or module. Students are boring with those media. They are not enthusiastic to write. Here, researcher wants to experiments a software media developed by Dianne Zairina. This software media is an E-Writing Materials. Researcher wants to know whether E-Writing materials can attract students motivation or not. This research belongs to quasi experimental research design with two groups samples which are not randomized. This research was conducted in SMP Al-Munawwariyyah. The population was second grade students where each class consisted of 32 students in average. The samples were taken from class A as experimental group and class B as control group. The result showed that experimental group had better writing achievement than control group. Based on the post test, mean scores of control group maintain in 77.44 while mean scores in experimental group increase to 82.44. In addition, the response about E-Writing materials from students based on researcher observation was good. Students enjoyed E-Writing Materials. It can be concluded that E-Writing materials is effective media to improve writing skill for English teacher at school

  17. Analysis of Functionally Graded Material Plates Using Triangular Elements with Cell-Based Smoothed Discrete Shear Gap Method

    Directory of Open Access Journals (Sweden)

    S. Natarajan

    2014-01-01

    Full Text Available A cell-based smoothed finite element method with discrete shear gap technique is employed to study the static bending, free vibration, and mechanical and thermal buckling behaviour of functionally graded material (FGM plates. The plate kinematics is based on the first-order shear deformation theory and the shear locking is suppressed by the discrete shear gap method. The shear correction factors are evaluated by employing the energy equivalence principle. The material property is assumed to be temperature dependent and graded only in the thickness direction. The effective properties are computed by using the Mori-Tanaka homogenization method. The accuracy of the present formulation is validated against available solutions. A systematic parametric study is carried out to examine the influence of the gradient index, the plate aspect ratio, skewness of the plate, and the boundary conditions on the global response of the FGM plates. The effect of a centrally located circular cutout on the global response is also studied.

  18. Experimental Investigation on Material Transfer Mechanism in WEDM of Pure Titanium (Grade-2

    Directory of Open Access Journals (Sweden)

    Anish Kumar

    2013-01-01

    Full Text Available This research work mainly focused on experimental investigation on material transfer mechanism in WEDM of pure titanium. The effects of machining parameters such as pulse on time, pulse off time, peak current, spark gap voltage, wire feed, and wire tension on the material removal rate (MRR, overcut, and surface roughness for pure titanium in WEDM process were explored. The selected machined samples were analyzed using energy dispersive X-ray analysis, scanning electron microscope, and X-ray diffraction techniques. It was observed from the results that a significant material transfer occurred from the dielectric, as well as tool, electrode on the work surface either in free form and/or in compound form. Also the multiresponse optimization of process parameters was done using desirability approach. The predictions from this model were validated by conducting experiments.

  19. Affects of Microgravity on the Polymerization and Material Properties of Biomedical Grade Polymers

    Science.gov (United States)

    Crane, Deborah J.

    2002-01-01

    the material of choice in the production of acetabular cups for hip and tibial cradles for knee orthopeadic implant components for over 30 years. Although UHMWPE is used for more than 1.5 million implants a year in the United States alone and more than 3 million implant surgeries a year worldwide, problems with debris particle formation, pitting and fracture continue to induce premature failure of implant components. chains produced during polymerization are capable of packing into crystalline structures called lamellae, which are embedded within randomly oriented amorphous regions. Crosslinks, or tie molecules bridge the crystalline structures, which contribute to the materials' toughness and strength as a biomedical material. Research has been conducted providing evidence that a crosslinked gradient at the articulating surface of the polymer component provides resistance to surface degradation and subsequent debris formation. Recently, the introduction of highly crosslinked UHMWPE had proven to reduce some of the problems associated with the applications of this polymer as a biomedical material and was seen as the answer to solving the continuing problems associated with UHMWPE implant components. Yet current research into the fatigue characteristics of highly crosslinked UHMWPE has shown that subsurface crack propagation and subsequent delamination continues to produce problematic debris generation. Studies have shown that various sterilization and accelerated aging (to emulate natural oxidation rates) protocols adversely effects the material properties. Additional research has shown that alignment of the lamellae, caused by processing technique, fabrication or surface articulation may be the precursor to debris particle formation. Processing techniques performed under high pressure has proven to effect the width of the crystalline lamellae and therefore, the material's response to wear and fracture. UHMWP due to a microgravity environment, which could be

  20. Materials characterization and fracture mechanics of a space grade dielectric silicone insulation

    Science.gov (United States)

    Abdel-Latif, A. I.; Tweedie, A. T.

    1982-01-01

    The present investigation is concerned with the DC 93-500 high voltage silicone insulation material employed to pot the gun and the collector end of a traveling wave tube (TWT) used on the Landsat D Satellite. The fracture mechanics behavior of the silicone resin was evaluated by measuring the slow crack velocity as a function of the opening mode of the stress intensity factor at +25 and -10 C, taking into account various uniaxial discrete strain values. It was found that the silicone resins slow crack growth is faster than that for a high voltage insulation polyurethane material at the same stress intensity factor value and room temperature.

  1. Membranes for periodontal regeneration: From commercially available to spatially designed and functionally graded materials

    Science.gov (United States)

    Bottino, Marco Cicero

    The aging of the global population will lead to a considerable increase in the number of surgical and restorative procedures related to oral rehabilitation or periodontal regeneration. Periodontitis is one of the most aggressive pathologies that concern the integrity of the periodontal system that can lead to the destruction of the periodontium. Guided tissue and guided bone regeneration (GTR/GBR) have been used for the repair and regeneration of periodontal tissues by utilizing an occlusive membrane. The goal of this dissertation is to advance the knowledge in the area of periodontal regeneration by investigating the properties of a commercially available freeze-dried collagen-based graft (AlloDermRTM) and by designing/fabricating a functionally graded membrane (FGM) via multilayer electrospinning. The effects of different rehydration times and of a simultaneous rehydration/crosslinking procedure on the biomechanical properties and matrix stability of the commercially available membrane were investigated. The results revealed that there are significant changes on the biomechanical properties of the graft as rehydration time increases. Moreover, it was demonstrated that the simultaneous rehydration/crosslinking protocol has a synergistic effect in terms of enhancing biomechanical properties. A FGM consisting of a core-layer (CL) and two functional surface-layers (SL) was fabricated via sequential electrospinning. Hydroxyapatite nanoparticles (n-HAp) were incorporated to enhance bone formation (SL facing bone defect), and metronidazole benzoate (MET) was added to prevent bacterial colonization (SL facing the epithelial tissue). Degradation studies performed on both the CL and the FGM confirmed that the design holds promise in terms of providing the required mechanical stability to avoid membrane collapse and, therefore, enhance bone regeneration. Finally, it was demonstrated that MET incorporation into the SL that would face epithelial tissue is effective in

  2. Three-dimensional free vibration analysis of functionally graded material plates resting on an elastic foundation

    Science.gov (United States)

    Amini, M. H.; Soleimani, M.; Rastgoo, A.

    2009-08-01

    This paper describes a method for three-dimensional free vibration analysis of rectangular FGM plates resting on an elastic foundation using Chebyshev polynomials and Ritz's method. The thickness can vary from thin to very thick. The elastic foundation is considered as a Winkler model. The analysis is based on a linear, small-strain, three-dimensional elasticity theory. The proposed technique yields very accurate natural frequencies and mode shapes of rectangular plates with arbitrary boundary conditions. A simple and general programme has been used for this purpose. For a plate with geometric symmetry, the vibration modes can be classified into symmetric and antisymmetric ones in that direction. In such a case, the computational cost can be greatly reduced while maintaining the same level of accuracy. Convergence studies and a comparison have been carried out using isotropic and FGM square plates with four simply-supported and clamped edges as examples. The results show that the present method enables rapid convergence, stable numerical operation and very high computational accuracy. Parametric investigations are presented for two-constituent metal-ceramic functionally graded clamped square plates on an elastic foundation with respect to different thickness-side ratios, gradient indexes and foundation stiffnesses.

  3. Three-dimensional free vibration analysis of functionally graded material plates resting on an elastic foundation

    International Nuclear Information System (INIS)

    Amini, M H; Soleimani, M; Rastgoo, A

    2009-01-01

    This paper describes a method for three-dimensional free vibration analysis of rectangular FGM plates resting on an elastic foundation using Chebyshev polynomials and Ritz's method. The thickness can vary from thin to very thick. The elastic foundation is considered as a Winkler model. The analysis is based on a linear, small-strain, three-dimensional elasticity theory. The proposed technique yields very accurate natural frequencies and mode shapes of rectangular plates with arbitrary boundary conditions. A simple and general programme has been used for this purpose. For a plate with geometric symmetry, the vibration modes can be classified into symmetric and antisymmetric ones in that direction. In such a case, the computational cost can be greatly reduced while maintaining the same level of accuracy. Convergence studies and a comparison have been carried out using isotropic and FGM square plates with four simply-supported and clamped edges as examples. The results show that the present method enables rapid convergence, stable numerical operation and very high computational accuracy. Parametric investigations are presented for two-constituent metal–ceramic functionally graded clamped square plates on an elastic foundation with respect to different thickness–side ratios, gradient indexes and foundation stiffnesses

  4. The First Cycle of Developing Teaching Materials for Fractions in Grade Five Using Realistic Mathematics Education

    Directory of Open Access Journals (Sweden)

    Hongki Julie

    2013-07-01

    Full Text Available There are 3 questions that will be answered in this study, namely (1what are the contexts that can be used to introduce the meaning ofmultiplication of two fractions and to find the result of multiplying two fractions, (2 how to use these contexts to help students construct the understanding of the meaning of multiplication of two fractions and find the result of multiplying two fractions, and (3 what is the impact of the teaching-learning process that has been designed by researchers on the process of students’ knowledge construction.Learning approach which was used in developing teaching materialsabout fractions is realistic mathematics approach. Lesson plan wascreated for fifth grade elementary school students. The type of research used is development research. According to Gravemeijer and Cobb (in Akker, Gravemeijer, McKeney, and Nieveen, 2006 there are three phases in development research, namely (1 preparation of the trial design, (2 the trial design, and (3 a retrospective analysis. This paper presents the results of the first cycle of three cycles that have been planned.

  5. Direct laser metal deposition of WC/Co/Cr powder by means of the functionally graded materials strategy

    Science.gov (United States)

    Angelastro, A.; Campanelli, S. L.

    2017-12-01

    One of the many applications of direct laser metal deposition (DLMD) is the realization of multilayer thick coatings having particular mechanical characteristics, such as high hardness. The objective of this work was to obtain a thick, very hard and wear resistant coating, containing a high percentage of tungsten carbide (WC), on an AISI 304 stainless steel substrate. In order to achieve this result, a tungsten carbide-cobalt-chrome (WC/Co/Cr) powder was processed by the DLMD method. WC/Co/Cr is a composite widely used as a wear-resistant material for cutting tools, molds, coatings and other severe applications. Because of its high hardness, poor ductility and low thermal expansion coefficient, depositing this material directly on the stainless steel substrate is very difficult. In order to overcome this problem, the strategy of functionally graded materials (FGM) was used. Colmonoy 227-F nickel alloy was chosen for this purpose in order to generate a mixture with the WC/Co/Cr powder. Four different materials were deposited, layer by layer, by mixing Colmonoy 227-F with an increasing amount of WC/Co/Cr powders, until obtaining a thick surface coating with a maximum amount of WC of 77.4 wt%. For each powder mixture, a mathematical model was applied to calculate optimal values of translation speed and overlap percentages. A metallographic examination was performed in order to detect macro- and micro-structures of the different materials. Finally, Vickers micro-hardness was measured at various locations along the transverse section to appreciate the gradual increase of the FGM hardness, starting from the substrate and culminating at the top surface of the last deposited material.

  6. Investigation on the corrosion behavior of nuclear grade stainless cladding materials

    International Nuclear Information System (INIS)

    Qiu Shaoyu; Sun Danqi; Li Yanling; He Yanchun; Zheng Jian

    2002-01-01

    Tests of pitting corrosion and intergranular corrosion of two Chinese stainless cladding materials are carried out according to standards of GB4334.7-84 and French RCC-M MC1310. Under the water chemistry condition simulating pressurized water reactors (PWRs) coolant (temperature, 345 degree C; B,800 mg/L; Li,2 mg/L), their stress corrosion and uniform corrosion behaviors are studied. The results show that no stress corrosion cracking in U-shape samples is found and average static uniform corrosion rate is less than 2 mg/dm 2 after testing in high temperature borated water for 5000 h. Both of stainless cladding materials have better corrosion resistance

  7. Irradiation effects of hydrogen and helium plasma on different grade tungsten materials

    Directory of Open Access Journals (Sweden)

    X. Liu

    2017-08-01

    Full Text Available Fine-grain tungsten alloys could be one of the solutions for the plasma facing materials of future DEMO reactors. In order to evaluate the service performances of the newly developed W alloys under edge plasma irradiation and the synergetic effect of fusion plasma together with high heat flux, both low energy He ions and high energy H, H/He mixed neutral beam irradiation on W-ZrC, W-K, W-Y2O3, W-La2O3 and CVD-W coating were performed respectively at a liner plasma facility (Dalian Nationality University, China and the neutral beam facility GLADIS (IPP, Germany. Surface damages were characterized, and the crack formation and extension behaviors under ELM-like transient loading after H and H/He mixed beam irradiation were also investigated in the 60kW EMS-60 facility (Electron beam Materials testing Scenario at SWIP (Southwestern Institute of Physics, China. The experimental results indicated that surface damages induced by low or high energy H/He ion/neutral beam didn't closely correlate with the type of tungsten materials. However, H/He (6at% He concentration neutral beam induced more significant surface damages of the tested W materials than only H neutral beam irradiation under the similar irradiation conditions. Similarly, the mixed H/He pre-exposure remarkably reduced the critical power of crack initiation compared with the un-irradiated samples under 100 repetitive loads of 1ms pulse, while no significant degeneration for the case of only H beam irradiation was observed.

  8. Effect of Projectile Materials on Foreign Object Damage of a Gas-Turbine Grade Silicon Nitride

    Science.gov (United States)

    Choi, Sung R.; Racz, Zsolt; Bhatt, Ramakrishna T.; Brewer, David N.; Gyekenyesi, John P.

    2005-01-01

    Foreign object damage (FOD) behavior of AS800 silicon nitride was determined using four different projectile materials at ambient temperature. The target test specimens rigidly supported were impacted at their centers by spherical projectiles with a diameter of 1.59 mm. Four different types of projectiles were used including hardened steel balls, annealed steel balls, silicon nitride balls, and brass balls. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to better understand the severity of local impact damage. The critical impact velocity where target specimens fail upon impact was highest with brass balls, lowest with ceramic ball, and intermediate with annealed and hardened steel balls. Degree of strength degradation upon impact followed the same order as in the critical impact velocity with respect to projectile materials. For steel balls, hardened projectiles yielded more significant impact damage than annealed counterparts. The most important material parameter affecting FOD was identified as hardness of projectiles and was correlated in terms of critical impact velocity, impact deformation, and impact load.

  9. Be-Cu gradient materials through controlled segregation. Basic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Muecklich, F.; Lorinser, M.; Hartmann, S.; Beinstingel, S. [Saarland Univ., Saarbruecken (Germany); Linke, J.; Roedig, M.

    1998-01-01

    The joining of materials has a fundamental problematic nature: Creating a sharp interface between two different materials causes a more or less extreme jump in the properties at this point. This may result in the failure of the component under mechanical or thermal loads. In some cases there are further difficulties caused by using a third component (e.g. the transformation of Ag-lead into Cd by neutron beams). The solution may be the creating of a functionally gradient material (FGM) Be-Cu. We discuss the advantage of such a FGM and the probabilities of an new procedure for manufacturing 1-dimensional FGMs. (author)

  10. Evaluation of casting textures in Al/Al{sub 3}Ti platelet functionally graded material fabricated by a centrifugal solid-particle method

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Y.; Eryu, H.; Yamamoto, T. [Dept. of Functional Machinery and Mechanics, Shinshu Univ., Ueda (Japan); Andiarwanto, S.; Miura, H. [Dept. of Mechanical Engineering and Intelligent Systems, The Univ. of Electro-Communications, Tokyo (Japan)

    2002-07-01

    In this study, crystal orientation of the Al matrix in Al/Al{sub 3}Ti FGMs fabricated by the centrifugal solid-particle method was investigated by using orientation image microscopy (OIM). It was found that strong orientation of the Al{sub 3}Ti platelets was developed in the FGM fabricated under large G number, which is the ratio of the centrifugal force to the gravity. Contrarily to the expectation, strong texture of the Al matrix was not developed in the FGM even by solidification under strong centrifugal force, Moreover, there exists no specific relationship of crystallographical orientation between Al matrix and Al{sub 3}Ti platelets. Therefore, it would be concluded that nucleation and growth of Al matrix grains keeping specific orientation relationship with the pre-existing solid platelets seem to be difficult under dynamic casting with centrifugal force. (orig.)

  11. Free vibration analysis of a rotary smart two directional functionally graded piezoelectric material in axial symmetry circular nanoplate

    Science.gov (United States)

    Mahinzare, Mohammad; Ranjbarpur, Hosein; Ghadiri, Majid

    2018-02-01

    In this article, free vibration of a rotating circular nanoplate made of two directional functionally graded piezo materials (two directional FGPM) is modeled based on the first shear deformation theory (FSDT). Based on the power-law model, electro-elastic properties of two directional FGP rotating circular nanoplates are supposed to change continuously along the thickness and radius. Employing the modified couple stress theory, the small size effect of the equations of the plate is considered. The governing equations of the first shear deformation theory (FSDT) for the studied plate are obtained based on Hamilton's principle; these equations are solved using differential quadrature method (DQM). It is shown that the vibration behavior of the plate is significantly affected by angular velocity, external electric voltage, size dependency and power-law index (thickness and radial directions).

  12. Vibration control of a functionally graded material plate patched with piezoelectric actuators and sensors under a constant electric charge

    Science.gov (United States)

    Kargarnovin, M. H.; Najafizadeh, M. M.; Viliani, N. S.

    2007-08-01

    In this paper active vibration control of functionally graded material (FGM) plates using piezoelectric sensor/actuator patches is studied. A simply supported FGM rectangular plate which is bonded with a piezoelectric rectangular patch (patches) on the top and/or bottom surface(s) as actuators/sensors is considered. When a constant electric charge is imposed, the governing differential equations of the motion are derived using classical laminated plate theory (CLPT). The solution for the motion equation is obtained using a Fourier series method and the effect of feedback gain and FGM volume fraction on the plate frequency and displacement (w) are studied. It is noticed that increasing the feedback gain leads to the reduction of frequency and displacement and therefore a better control of the plate's vibration. Moreover, by increasing the value of the FGM volume fraction the resonant frequency decreases.

  13. The modelling and design of smart structures using functionally graded materials and piezoelectrical sensor/actuator patches

    Science.gov (United States)

    Liew, K. M.; Sivashanker, S.; He, X. Q.; Y Ng, T.

    2003-08-01

    Finite element formulations are derived for static and dynamic analysis and the control of functionally graded material (FGM) plates under environments subjected to a temperature gradient, using linear piezoelectricity theory and first-order shear deformation theory. The multi-input-multi-output (MIMO) system with four collocated sensors and actuators is applied to provide active feedback control of the integrated FGM plate in a closed loop system. The distributed piezoelectrical sensors monitor the structural deformation due to the direct piezoelectrical effect and the distributed actuators control the deformation via the converse piezoelectrical effect. Numerical results for the static and dynamic control have been presented for the FGM plate, which consists of zirconia and aluminum. The purpose of the examples, which consist of a FGM plate with four collocated sensors and actuators used as MIMO system, is to determine the optimum configurations of the sensor/actuator pairs under various thermal and mechanical load fields.

  14. Green’s Function Approach to Solution of Transient Temperature for Thermal Stresses of Functionally Graded Material

    Science.gov (United States)

    Kim, Kui-Seob; Noda, Naotake

    The transient temperature solution for a functionally graded material (FGM) is formulated by Green’s function based on the Galerkin method. An approximate solution that satisfies the homogeneous boundary condition is substituted into the governing equation to yield an eigenvalue problem. To solve the eigenvalue problem, the eigenfunctions are approximated by a series of polynomials satisfying the homogeneous boundary condition. The Galerkin method is used to determine the coefficients of eigenfunctions. The transient temperature solution for a general heat conduction equation with a source and nonhomogeneous boundary conditions is obtained by using Green’s function, which is expressed by eigenvalues and corresponding eigenfunctions. Transient thermal stresses in a FGM plate and a FGM hollow circular cylinder are discussed.

  15. Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer.

    Science.gov (United States)

    Qian, Zheng-Hua; Jin, Feng; Lu, Tianjian; Kishimoto, Kikuo; Hirose, Sohichi

    2010-01-01

    The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.

  16. Analysis instrument test on mathematical power the material geometry of space flat side for grade 8

    Science.gov (United States)

    Kusmaryono, Imam; Suyitno, Hardi; Dwijanto, Karomah, Nur

    2017-08-01

    The main problem of research to determine the quality of test items on the material side of flat geometry to assess students' mathematical power. The method used is quantitative descriptive. The subjects were students of class 8 as many as 20 students. The object of research is the quality of test items in terms of the power of mathematics: validity, reliability, level of difficulty and power differentiator. Instrument mathematical power ratings are tested include: written tests and questionnaires about the disposition of mathematical power. Data were obtained from the field, in the form of test data on the material geometry of space flat side and questionnaires. The results of the test instrument to the reliability of the test item is influenced by many factors. Factors affecting the reliability of the instrument is the number of items, homogeneity test questions, the time required, the uniformity of conditions of the test taker, the homogeneity of the group, the variability problem, and motivation of the individual (person taking the test). Overall, the evaluation results of this study stated that the test instrument can be used as a tool to measure students' mathematical power.

  17. Green Chemistry: Effect of Microwave Irradiationon Synthesis of Chitosan for Biomedical Grade Applications of Biodegradable Materials

    Directory of Open Access Journals (Sweden)

    Amri Setyawati

    2016-10-01

    Full Text Available Microwave assisted chitosan synthesis as biodegradable material for biomedical application has been done. The purpose of this research is to synthesis of chitosan with high DD and low molecular weight using microwave energy, the study of reaction conditions include parameters of power and reaction time. Chitosan was prepared by deacetylation of chitin with 60% NaOH solution. Conventional method has been done by reflux for 90minutes, resulting chitosan with DD of 79.5%, 72.6% yields and molecular weight 6051 g/mol. Green chemistry method using microwave radiation at 800 Watts for 5 minutes has produced chitosan with highest DD, yield and molecular weight of 86%, 75% and 3797 g/mole respectively. Synthesis of Chitosan by microwave radiation method can save 10x electrical energy for the reaction, also rapidly and effectively to produce chitosan with low molecular weight compared to conventional methods

  18. Development of a WebQuest as instructional material in teaching biodiversity for grade 8 learners

    Science.gov (United States)

    Genovia, Jerson A.; Eslit, April Rose C.; Tamse, Agnes Lera G.; Barquilla, Manuel B.

    2018-01-01

    WebQuest is an inquiry-based learning activity that allows students to learn the lesson using the information provided in the internet resources. The study aimed to develop and implement the WebQuest on Biodiversity. Primarily, this research determines the students' performances in the achievement test after WebQuest was implemented to them. Secondly, it is also to investigate on their attitudes towards Biology before and after the activity as well as the level of development of their 21st Century Skills. This research utilized Quasi-experimental Non-randomized One Group Pretest/Posttest Design. The developed WebQuest that is based from the K-12 curriculum competencies were evaluated by selected experts in the Content (2), Pedagogy (2) and ICT (2) to assess the said activity in terms of content, pedagogy and ICT effects. It was then implemented in an intact group of grade 8 students. Findings revealed that the developed WebQuest was rated "Excellent" for Content, Pedagogy and TCT effects. After utilizing the WebQuest activity on Biodiversity, students acquired more knowledge on the topic shows by the mean difference of 2.42, which is highly significant based on t-test result. The overall students' attitude towards Biology as a subject changed positively after they did the activity due to novelty effects and the WebQuest itself with the mean difference of 0.46. Moreover, results shows that the students can developed 21st century skills considering that the Likert scale survey was given only to the students after the activity. Based on the result, 97% of total responses favored to have developed Critical Thinking skills, 98% on Collaboration skills, 97% on Creativity and Innovative skills, 94% on Communication skills, 97% on Self-Decision skills, and 97% on ICT skills. The concentration of percentage of responses differed in two classes because Class A was composed of highlyselected students who underwent an entrance examination upon admission in school and Class B

  19. Non-linear panel flutter for temperature-dependent functionally graded material panels

    Science.gov (United States)

    Ibrahim, Hesham Hamed; Tawfik, Mohammad; Al-Ajmi, Mohammed

    2008-01-01

    The non-linear flutter and thermal buckling of an FGM panel under the combined effect of elevated temperature conditions and aerodynamic loading is investigated using a finite element model based on the thin plate theory and von Karman strain-displacement relations to account for moderately large deflection. The aerodynamic pressure is modeled using the quasi-steady first order piston theory. The governing non-linear equations are obtained using the principal of virtual work adopting an approach based on the thermal strain being a cumulative physical quantity to account for temperature dependent material properties. This system of non-linear equations is solved by Newton-Raphson numerical technique. It is found that the temperature increase has an adverse effect on the FGM panel flutter characteristics through decreasing the critical dynamic pressure. Decreasing the volume fraction enhances flutter characteristics but this is limited by structural integrity aspect. The presence of aerodynamic flow results in postponing the buckling temperature and in suppressing the post buckling deflection while the temperature increase gives way for higher limit cycle amplitude.

  20. Fracture of functionally graded materials: application to hydrided zircaloy; Fissuration des materiaux a gradient de proprietes: application au zircaloy hydrure

    Energy Technology Data Exchange (ETDEWEB)

    Perales, F

    2005-12-15

    This thesis is devoted to the dynamic fracture of functionally graded materials. More particularly, it deals with the toughness of nuclear cladding at high burnup submitted to transient loading. The fracture is studied at local scale using cohesive zone model in a multi body approach. Cohesive zone models include frictional contact to take into account mixed mode fracture. Non smooth dynamics problems are treated within the Non-Smooth Contact Dynamics framework. A multi scale study is necessary because of the dimension of the clad. At microscopic scale, the effective properties of surface law, between each body, are obtained by periodic numerical homogenization. A two fields Finite Element formulation is so written. An extended formulation of the NSCD framework is obtained. The associated software allows to simulate, in finite deformation, from the crack initiation to post-fracture behavior in heterogeneous materials. At microscopic scale, random RVE calculations are made to determine effective properties. At macroscopic scale, calculations of part of clad are made to determine the role of the mean hydrogen concentration and gradient of hydrogen parameters in the toughness of the clad under dynamic loading. (author)

  1. THE FOOTWEAR DESIGNING SESSION USING CRISPIN DYNAMICS ENGINEER. PART II: Creating the parts, Estimating the material consumption, Grading

    Directory of Open Access Journals (Sweden)

    IOVAN-DRAGOMIR Alina

    2015-05-01

    Full Text Available The diversification and customization of products are important characteristic of the modern economy and especially of the fashion industry. Because of this, the lifetime of the footwear product is very short and result the necessity to cut the design and production time. By classic methodology, designing footwear is a very complex and laborious activity. That is because classic methodology requires many graphic executions using manual means, which consume a lot of the producer’s time. With CRISPIN Dynamics, one can visualize a range of designs on-screen; work out the costs of a new style and even cut out sample shoe components. Reliance on manual skills is largely eliminated, so the staff can work creatively, but with increased accuracy and productivity. One can even send designs to a distant office or manufacturing centre in a matter of minutes. This paper presents the basic function of CRISPIN Dynamics CAD Suite Engineer for footwear design. The process of new product development has six stapes: digitized form of the medium copy, last flatting, model drawing, creation and management of individual parts, estimation of material consumption, multiplying the designed footwear product’s pattern. This product has been developed for shoemakers who wish to ensure that their business remains competitive by increasing the efficiency, speed and accuracy of pattern development and grading.

  2. Comparative study of the shear bond strength of various veneering materials on grade II commercially pure titanium.

    Science.gov (United States)

    Lee, Eun-Young; Jun, Sul-Gi; Wright, Robert F; Park, Eun-Jin

    2015-02-01

    To compare the shear bond strength of various veneering materials to grade II commercially pure titanium (CP-Ti). Thirty specimens of CP-Ti disc with 9 mm diameter and 10 mm height were divided into three experimental groups. Each group was bonded to heat-polymerized acrylic resin (Lucitone 199), porcelain (Triceram), and indirect composite (Sinfony) with 7 mm diameter and 2 mm height. For the control group (n=10), Lucitone 199 were applied on type IV gold alloy castings. All samples were thermocycled for 5000 cycles in 5-55℃ water. The maximum shear bond strength (MPa) was measured with a Universal Testing Machine. After the shear bond strength test, the failure mode was assessed with an optic microscope and a scanning electron microscope. Statistical analysis was carried out with a Kruskal-Wallis Test and Mann-Whitney Test. The mean shear bond strength and standard deviations for experimental groups were as follows: Ti-Lucitone 199 (12.11 ± 4.44 MPa); Ti-Triceram (11.09 ± 1.66 MPa); Ti-Sinfony (4.32 ± 0.64 MPa). All of these experimental groups showed lower shear bond strength than the control group (16.14 ± 1.89 MPa). However, there was no statistically significant difference between the Ti-Lucitone 199 group and the control group, and the Ti-Lucitone 199 group and the Ti-Triceram group. Most of the failure patterns in all experimental groups were adhesive failures. The shear bond strength of veneering materials such as heat-polymerized acrylic resin, porcelain, and indirect composite to CP-Ti was compatible to that of heatpolymerized acrylic resin to cast gold alloy.

  3. Health Curriculum Materials: Grades 4, 5, and 6, Strand I, Physical Health; Disease Prevention and Control. Special Edition for Evaluation and Discussion.

    Science.gov (United States)

    Johnstone, Robert H.; And Others

    This publication contains curriculum material and suggestions for teaching disease prevention and control in grades four, five and six. Objectives of this program include; 1) an understanding of the basic differences between communicable and non-communicable disease syndromes, and a familiarity with representative diseases from each of these…

  4. Gender-Based Content of Educational Materials for the Study of Serbian Language in Lower-Stage Grades of Elementary Education

    Science.gov (United States)

    Trifunovic, Vesna; Petrovic, Ruzica

    2014-01-01

    This paper presents the results of analysis of educational materials for the study of Serbian language in lower-stage grades of elementary education (intended for students from 7 through 11 years old) from gender perspective. The first part of the paper presents the process of institutionalization of gender-based education in the Republic of…

  5. Strand V: Education for Survival. First Aid and Survival Education. Health Curriculum Materials. Grades 7-9.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    GRADES OR AGES: Grades 7-9. SUBJECT MATTER: First aid and survival education. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into five sections: bandaging skills, control of bleeding, conditions caused by extremes in temperatures, foreign substances in body openings, and other common emergencies. The publication format of four columns…

  6. The Content Analysis, Material Presentation, and Readability of Curriculum 2013 Science Textbook for 1st Semester of Junior High School 7th Grade

    Directory of Open Access Journals (Sweden)

    Endik Deni Nugroho

    2017-07-01

    Full Text Available Based on the early observation by researchers of the two Science textbooks 7thGrade about biological material, 1stand 2ndsemester of curriculum 2013, there were errors in the material presentation and legibility. This study aimed to compare and find the contents suitability of the book based on standard of competence and basic competences, readability, materials presentation and supporting material in the science textbook VII grade, 1st and 2nd semester and measured student legibility. This study used a qualitative descriptive approach by using document analysis. The data resources were obtained by using purposive, the data collection was triangulation, data analysis was inductive/qualitative and the results emphasized the meaning. This research results showed that the Integrated Sciences and Sciences textbook 1st and 2nd semester meet the standards of the core competencies and basic competence on the syllabus curriculum 2013 and also meet the books standart. The results of the analysis conducted in misstatement concept and principles and material llustration in the Integrated Science textbook 1st semester were found 5 misstatement concept, for the presentation of the principles and material illustration was found no error. In the book Integrated Sciences there was no delivery errors concept, principle, and material illustration. Science textbook 1st semester found 8 concepts misstatements and 8 illustration material misstatements. In general, Integrated Sciences and Sciences textbooks 1st and 2nd semester are illegibility so not appropriate for students.

  7. The properties of thickness-twist (TT) wave modes in a rotated Y-cut quartz plate with a functionally graded material top layer.

    Science.gov (United States)

    Wang, Bin; Qian, Zhenghua; Li, Nian; Sarraf, Hamid

    2016-01-01

    We propose the use of thickness-twist (TT) wave modes of an AT-cut quartz crystal plate resonator for measurement of material parameters, such as stiffness, density and material gradient, of a functionally graded material (FGM) layer on its surface, whose material property varies exponentially in thickness direction. A theoretical analysis of dispersion relations for TT waves is presented using Mindlin's plate theory, with displacement mode shapes plotted, and the existence of face-shear (FS) wave modes discussed. Through numerical examples, the effects of material parameters (stiffness, density and material gradient) on dispersion curves, cutoff frequencies and mode shapes are thoroughly examined, which can act as a theoretical reference for measurements of unknown properties of FGM layer. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Two-dimensional model for subthreshold current and subthreshold swing of graded-channel dual-material double-gate (GCDMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Kumar, Sanjay; Singh, Balraj; Singh, Kunal; Jit, Satyabrata

    2017-06-01

    The subthreshold performance of graded-channel dual-material double-gate (GCDMDG) MOSFETs is examined through two-dimensional (2D) analytical modeling of subthreshold-current (SC) and subthreshold-swing (SS). The potential function obtained by using the parabolic approach to solve the 2D Poisson's equation, has been used to formulate SC and SS characteristics of the device. The variations of SS against different device parameters have been obtained with the help of effective conduction path parameter. The SC and SS characteristics of the GCDMDG MOS transistor have been compared with those of the dual-material double-gate (DMDG) and simple graded-channel double-gate (GCDG) MOS structures to show its better subthreshold characteristics over the latter two devices. The results of the developed model are well-agreed with the commercially available SILVACO ATLAS™ simulator data.

  9. The Development Of Scientific Approach-oriented Science Learning Materials On Biotechnology And Food Production Topics For Grade IX Junior High School

    OpenAIRE

    Febrina, Ririn Febrina Ririn; Natalina, Mariani Natalina Mariani; Suryawati, Evi Suryawati Evi

    2015-01-01

    The aim of this research was to develop scientific approach-oriented science learning materials on biotechnology and food production topic for grade IX junior high school. The developments consisted of syllabus, lesson plans, worksheets, authentic assessment (paper and pencil test, attitude assessment, performance assessment, product assessment, project assessment, self-assessment and portofolio assessment). The development was conducted at Biology Education University of Riau and the pilot t...

  10. Localized corrosion studies on materials proposed for a safety-grade sodium-to-air decay-heat removal system for fast breeder reactors

    International Nuclear Information System (INIS)

    Mudali, U.K.; Khatak, H.S.; Dayal, R.K.; Gnanamoorthy, J.B.

    1993-01-01

    The present investigation was carried out to assess the localized corrosion resistance of materials proposed for the construction of the safety-grade sodium-to-air decay-heat removal system for fast breeder reactors. The materials, such as Alloy 800, 9Cr-1 Mo steel, and type 316LN stainless steel, in different microstructural conditions were assessed for pitting and stress-corrosion cracking resistances in a chloride medium. The results indicated that 9Cr-1Mo steel in the normalized and tempered condition can be considered for the above application from the standpoint of corrosion resistance

  11. Ceramic-Based 4D Components: Additive Manufacturing (AM) of Ceramic-Based Functionally Graded Materials (FGM) by Thermoplastic 3D Printing (T3DP).

    Science.gov (United States)

    Scheithauer, Uwe; Weingarten, Steven; Johne, Robert; Schwarzer, Eric; Abel, Johannes; Richter, Hans-Jürgen; Moritz, Tassilo; Michaelis, Alexander

    2017-11-28

    In our study, we investigated the additive manufacturing (AM) of ceramic-based functionally graded materials (FGM) by the direct AM technology thermoplastic 3D printing (T3DP). Zirconia components with varying microstructures were additively manufactured by using thermoplastic suspensions with different contents of pore-forming agents (PFA), which were co-sintered defect-free. Different materials were investigated concerning their suitability as PFA for the T3DP process. Diverse zirconia-based suspensions were prepared and used for the AM of single- and multi-material test components. All of the samples were sintered defect-free, and in the end, we could realize a brick wall-like component consisting of dense (material, or especially, multi-functional components.

  12. Effects of Analogical vs. Schematic Illustrations on Initial Learning and Retention of Technical Material by Eighth-Grade Students.

    Science.gov (United States)

    McAlister, Brian K.

    The effects of analogical and schematic illustrations on the comprehension and retention of expository prose were compared. The population was 191 eighth-grade students at Mahomet Junior High School, Illinois; 134 students' scores were used. Subjects were assigned to two groups through the random distribution of treatment booklets that included a…

  13. Micro-mechanical investigation of the effect of fine content on mechanical behavior of gap graded granular materials using DEM

    Directory of Open Access Journals (Sweden)

    Taha Habib

    2017-01-01

    Full Text Available In this paper, we present a micro-mechanical study of the effect of fine content on the behavior of gap graded granular samples by using numerical simulations performed with the Discrete Element Method. Different samples with fine content varied from 0% to 30% are simulated. The role of fine content in reinforcing the granular skeleton and in supporting the external deviatoric stress is then brought into the light.

  14. Mathematical Communication Ability by Grade VII Students Using a Themed Problem Based Learning with Scaffolding on Rectangle Materials

    OpenAIRE

    Didik Adi Saputro; Masrukan Masrukan; Arief Agoestanto

    2017-01-01

    The aim of research to test students' mathematical communication used themed of PBL with scaffolding, themed of PBL and PBL achieve mastery learning;to test students' mathematical communication that used the themed of PBL with scaffolding, themed of PBL and PBL; and to test students' mathematical communication for the low, medium group, and a high-group themed of PBL with scaffolding, themed of PBL and PBL. This type of research is quantitative research. The Population is seventh grade studen...

  15. Effect of gradient dielectric coefficient in a functionally graded material (FGM) substrate on the propagation behavior of love waves in an FGM-piezoelectric layered structure.

    Science.gov (United States)

    Cao, Xiaoshan; Shi, Junping; Jin, Feng

    2012-06-01

    The propagation behavior of Love waves in a layered structure that includes a functionally graded material (FGM) substrate carrying a piezoelectric thin film is investigated. Analytical solutions are obtained for both constant and gradient dielectric coefficients in the FGM substrate. Numerical results show that the gradient dielectric coefficient decreases phase velocity in any mode, and the electromechanical coupling factor significantly increases in the first- and secondorder modes. In some modes, the difference in Love waves' phase velocity between these two types of structure might be more than 1%, resulting in significant differences in frequency of the surface acoustic wave devices.

  16. Using Space for a Better Foundation on Earth: Mechanics of Granular Materials. Educational Brief. Grades 5-8.

    Science.gov (United States)

    Alshibli, Khalid

    This publication presents a science activity and instructional information on mechanics of granular materials, interparticle friction and geometric interlocking between particles which is a fundamental concept in many fields like earthquakes. The activity described in this document focuses on the principal strength of granular materials,…

  17. Using Space for a Better Foundation on Earth: Mechanics of Granular Materials. Educational Brief. Grades 9-12.

    Science.gov (United States)

    Alshibli, Khalid

    This publication presents a science activity and instructional information on the mechanics of granular materials, interparticle friction and geometric interlocking between particles which is a fundamental concept in many fields like in the study of earthquakes. This document describes the Mechanics of Granular Materials (MGM) experiments which…

  18. Optimization of a Functionally Graded Material Stem in the Femoral Component of a Cemented Hip Arthroplasty: Influence of Dimensionality of FGM

    Directory of Open Access Journals (Sweden)

    Abdellah Ait Moussa

    2017-01-01

    Full Text Available The longevity of hip prostheses is contingent on the stability of the implant within the cavity of the femur bone. The cemented fixation was mostly adopted owing to offering the immediate stability from cement-stem and cement-bone bonding interfaces after implant surgery. Yet cement damage and stress shielding of the bone were proven to adversely affect the lifelong stability of the implant, especially among younger subjects who tend to have an active lifestyle. The geometry and material distribution of the implant can be optimized more efficiently with a three-dimensional realistic design of a functionally graded material (FGM. We report an efficient numerical technique for achieving this objective, for maximum performance stress shielding and the rate of early accumulation of cement damage were concurrently minimized. Results indicated less stress shielding and similar cement damage rates with a 2D-FGM implant compared to 1D-FGM and Titanium alloy implants.

  19. Analytical modeling of linearly graded alloy material gate recessed ultra thin body source/drain SON MOSFET

    Science.gov (United States)

    Dutta, Pranab Kishore; Manna, Bibhas; Sarkar, Subir Kumar

    2015-01-01

    An explicit analytical model of surface potential profile and threshold voltage of work function engineered gate (WFEG) recessed source/drain (Re S/D) MOSFET has been presented in this paper. A two dimensional Poisson's equation has been solved with parabolic potential approximation to establish the expressions of front and back channel surface potential distribution and the threshold voltage has been derived from the minima of such obtained potential. In this work, the benefits of linearly graded binary alloy gate and recessed source/drain structures are expected to be available simultaneously in ultra short channel SOI/SON MOSFETs structures. Analytical results are compared with those obtained from the 2D MEDICI device simulator to validate our present model.

  20. The Effect of Different Storage Conditions on the Physical Properties of Pigmented Medical Grade I Silicone Maxillofacial Material

    Science.gov (United States)

    Al-Dharrab, Ayman A.; Tayel, Seham B.; Abodaya, Mona H.

    2013-01-01

    Objective. This study aimed to evaluate the effect of different storage solutions that simulate acidic, alkaline, and sebum conditiions on the physical properties of pigmented (colorant elastomer) cosmesil M511 maxillofacial prosthetic material. Materials and Methods. Sixty specimens were prepared according to the manufacturer's instructions and were tested before and after immersion of different storage conditions for six months at 37 °C. The following tests were performed: color changes (group I), solution absorption (group II), surface roughness (group III), and scanning electron microscopy (group IV). Results. There were no significant changes observed in the color and solution absorption tests while surface roughness revealed significant difference between control group and other testing storage medium groups, and this result was supported by SEM analysis that revealed limited surface changes. Conclusions. Cosmaseil material is an acceptable cross-linked formulation that withstands storage in different solutions with variable pH. The addition of pigment cannot vary the physical properties of these materials. Surface roughness test as well as SEM microscopic study showed moderate changes indicating a limited effect on the surface of the material. PMID:23606978

  1. The English Teacher's Survival Guide: Ready-To-Use Techniques & Materials for Grades 7-12. 2nd Edition

    Science.gov (United States)

    Brandvik, Mary Lou; McKnight, Katherine S.

    2011-01-01

    This unique time-saving book is packed with tested techniques and materials to assist new and experienced English teachers with virtually every phase of their job from lesson planning to effective discipline techniques. The book includes 175 easy-to-understand strategies, lessons, checklists, and forms for effective classroom management and over…

  2. Standard test method for analysis of isotopic composition of uranium in nuclear-grade fuel material by quadrupole inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This test method is applicable to the determination of the isotopic composition of uranium (U) in nuclear-grade fuel material. The following isotopic weight percentages are determined using a quadrupole inductively coupled plasma-mass spectrometer (Q-ICP-MS): 233U, 234U, 235U, 236U, and 238U. The analysis can be performed on various material matrices after acid dissolution and sample dilution into water or dilute nitric (HNO3) acid. These materials include: fuel product, uranium oxide, uranium oxide alloys, uranyl nitrate (UNH) crystals, and solutions. The sample preparation discussed in this test method focuses on fuel product material but may be used for uranium oxide or a uranium oxide alloy. Other preparation techniques may be used and some references are given. Purification of the uranium by anion-exchange extraction is not required for this test method, as it is required by other test methods such as radiochemistry and thermal ionization mass spectroscopy (TIMS). This test method is also described i...

  3. Mathematical Communication Ability by Grade VII Students Using a Themed Problem Based Learning with Scaffolding on Rectangle Materials

    Directory of Open Access Journals (Sweden)

    Didik Adi Saputro

    2017-08-01

    Full Text Available The aim of research to test students' mathematical communication used themed of PBL with scaffolding, themed of PBL and PBL achieve mastery learning;to test students' mathematical communication that used the themed of PBL with scaffolding, themed of PBL and PBL; and to test students' mathematical communication for the low, medium group, and a high-group themed of PBL with scaffolding, themed of PBL and PBL. This type of research is quantitative research. The Population is seventh grade students of SMPN 22 Semarang and the sample class VII E, F and VII VII G. Used normality test, homogenity test, equality test on average, the proportion of one-party test, one way anova test, and scheffe test. The results showed that (1 Student’s mathematical communication ability using themed of PBLwith Scaffolding strategy,themed of PBL, and PBL achieve the completeness of learning, (2 there is a difference in the classroom using the themed of PBL with scaffolding, themed of PBL, as well as PBL, (3 For the low, medium, high and there is a difference in the classroom using the themed of PBL with scaffolding, themed of PBL and PBL.

  4. In vivo micronucleus studies with 6 titanium dioxide materials (3 pigment-grade & 3 nanoscale) in orally-exposed rats.

    Science.gov (United States)

    Donner, E M; Myhre, A; Brown, S C; Boatman, R; Warheit, D B

    2016-02-01

    Six pigment-grade (pg) or ultrafine (uf)/nanoscale (anatase and/or rutile) titanium dioxide (TiO2) particulates were evaluated for in vivo genotoxicity (OECD 474 Guidelines) in male and female rats by two different laboratories. All test materials were robustly characterized. The BET surface areas of the pg and uf samples ranged from 7 to 17 m(2)/g and 50 to 82 m(2)/g respectively. The materials were assessed for induction of micronuclei and toxicity in bone marrow by analyzing peripheral blood reticulocytes (RETs) by flow cytometry. Single oral gavage doses of 500, 1000 or 2000 mg/kg body weight (bw) of each material were implemented with concurrent negative (water) and positive controls (cyclophosphamide). Approximately 48 and 72 h after exposure, blood samples were collected and 20,000 RETs per animal were analyzed. For each of the six tests, there were no biologically or toxicologically relevant increases in the micronucleated RET frequency in any TiO2 exposed group at either time point at any dose level. In addition, there were a lack of biologically relevant decreases in %RETs among total erythrocytes. All six TiO2 test substances were negative for in vivo genotoxicity effects; however, it is noted that the exposure to target tissues was likely negligible. One pigment grade and one ultrafine material each were evaluated for potential systemic exposure/uptake from the gastrointestinal tract by analysis of TiO2 into blood and liver. No significant increases in TiO2 over controls were measured in blood (48 or 72 h) or liver (72 h) following exposures to 2000 mg/kg bw TiO2. These data indicate that there was no absorption of the test material from the gastrointestinal tract into the blood circulation and the lack of genotoxic effects is therefore attributed to a lack of exposure due to the inability of the test material to migrate from the gastrointestinal tract into the blood and then into target tissues. Copyright © 2015 Elsevier Inc. All rights

  5. A Technological Comparison of Six Processes for the Production of Reduction-Grade Alumina from Non-Bauxitic Raw Materials

    Science.gov (United States)

    Bengtson, K. B.

    The U. S. Bureau of Mines, by means of a contract with Kaiser Engineers and with Kaiser Aluminum & Chemical Corporation as a subcontractor, has sponsored a technological and an economic evaluation of six candidate processes for the manufacture of alumina from certain U. S. raw materials other than bauxite. This paper describes each process. Flow diagrams and the total energy requirement for each process are included. Important characteristics affecting the economics of producing alumina by each process are discussed, and some presently unsolved technical problems are identified. The extraction of alumina from clay via hydrochloric acid with iron separation by solvent extraction, and the crystallization of intermediate AlCl3·6H2O through the introduction of HCl gas into the pregnant mother liquor, appears to be technically feasible and the most attractive of the six raw material/process combinations.

  6. Student’s Misconception of Digestive System Materials in MTs Eight Grade of Malang City and the Role of Teacher’s Pedadogic Competency in MTs

    Directory of Open Access Journals (Sweden)

    Yuswa Istikomayanti

    2017-07-01

    Full Text Available Misconception research has important value in the development of students' thinking processes especially in science field. As the identification of important concepts that must be mastered by the students can be done, the teacher will easily able to emphasis the important or main concepts. This study aims to identify the students’ misconception in digestive system materials in eight grade of MTs and teacher pedagogic competence role. The survey was conducted in 8A (16 students and 8B (17 students MTs Muhammadiyah 1 and 8E (19 students Surya Buana Malang. The stages of research survey were: preparation of research goals (formulation, sample determination, preparation and instruments validation, data collection, and data analysis. The instruments used were: misconception test, student response questionnaire, learning observation guide, and teacher pedagogic competency form. The findings of the learning outcomes were discussed with the observer team, which then were assessed by using the assessment rubric and classified into the categories of student misconceptions. The results showed that the three teachers, neither certified nor uncertified were proved to be limited in overcoming misconceptions in the learning process; meanwhile, the results of students’ misconception test were mostly reach only level 3 (medium. Thus, the study of misconceptions of the digestive system material or other physiological material matter needs to get the attention of the teachers and educational practitioners.

  7. Materials

    CSIR Research Space (South Africa)

    Van Wyk, Llewellyn V

    2009-02-01

    Full Text Available community. The construction industry is a significantly consumer of materials, using 50 per cent of all products produced globally. Building materials is any material which is used for a construction purpose. Many of these materials are sources from natural...

  8. Francais de base. Programme de 9 ans, materiel didactique: 4e, 5e et 6e annees (Core French. Nine-Year Study Program, Instructional Materials: 4th, 5th and 6th Grades).

    Science.gov (United States)

    Manitoba Dept. of Education, Winnipeg. Bureau of French Education.

    Official instructional materials for the first three years (grades 4-6) of the Manitoba Department of Education's core French language program consist of units in geography, weather and calendars, holidays, and music designed for each of the three instructional levels. The units on geography focus on Manitoba and Canada. Units on the calendar and…

  9. Applied methodology to mineralogic/petrographic characterization and to the liberation grade of material proceeding from physics tests of uranium phosphate ores of Itataia - Ce, Brazil

    International Nuclear Information System (INIS)

    Salas, H.T.; Murta, R.L.L.

    1984-01-01

    A method, had been developed to determination of the liberation grade, was applied to uranium phosphate ore from Itataia rreserves, in Ceara, Brazil. The liberation grade was calculated from the petrographic analysis with quantitative mineralogy in special thin microscopic slides. (L.H.) [pt

  10. Applied methodology to mineralogic/petrographic characterization and to the liberation grade of material proceeding from physical tests of uranium phosphate ores of Itataia-Ce, Brazil

    International Nuclear Information System (INIS)

    Salas, H.T.; Murta, R.L.L.

    1984-01-01

    A method, had been developed to determination of the liberation grade, was applied to uranium-phosphate ore from Itataia reserves, in Ceara Brazil. The liberation grade was calculated from the petrographic analysis with quantitative mineralogy in special thin microscopic slides. (L.H.) [pt

  11. Tumor Grade

    Science.gov (United States)

    ... Peer Review and Funding Outcomes Step 4: Award Negotiation & Issuance Manage Your Award Grants Management Contacts Monitoring ... may require immediate or more aggressive treatment. The importance of tumor grade in planning treatment and determining ...

  12. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Graded geometry and Poisson reduction

    OpenAIRE

    Cattaneo, A S; Zambon, M

    2009-01-01

    The main result of [2] extends the Marsden-Ratiu reduction theorem [4] in Poisson geometry, and is proven by means of graded geometry. In this note we provide the background material about graded geometry necessary for the proof in [2]. Further, we provide an alternative algebraic proof for the main result. ©2009 American Institute of Physics

  14. Developmental toxicity studies with 6 forms of titanium dioxide test materials (3 pigment-different grade & 3 nanoscale) demonstrate an absence of effects in orally-exposed rats.

    Science.gov (United States)

    Warheit, D B; Boatman, R; Brown, S C

    2015-12-01

    Six different commercial forms and sizes of titanium dioxide particles were tested in separate developmental toxicity assays. The three pigment-grade (pg) or 3 ultrafine (uf)/nanoscale (anatase and/or rutile) titanium dioxide (TiO2) particle-types were evaluated for potential maternal and developmental toxicity in pregnant rats by two different laboratories. All studies were conducted according to OECD Guideline 414 (Prenatal Developmental Toxicity Study). In addition, all test materials were robustly characterized. The BET surface areas of the pg and uf samples ranged from 7 to 17 m(2)/g and 50-82 m(2)/g respectively (see Table 1). The test substances were formulated in sterile water. In all of the studies, the formulations were administered by oral gavage to time-mated rats daily beginning around the time of implantation and continuing until the day prior to expected parturition. In 3 of the studies (uf-1, uf-3, & pg-1), the formulations were administered to Crl:CD(SD) rats beginning on gestation day (GD) 6 through GD 20. In 3 additional studies (uf-2, and pg-2, pg-3 TiO2 particles), the formulations were administered to Wistar rats beginning on GD 5 through 19. The dose levels used in all studies were 0, 100, 300, or 1000 mg/kg/day; control group animals were administered the vehicle. During the in-life portions of the studies, body weights, food consumption, and clinical observations before and after dosing were collected on a daily basis. All dams were euthanized just prior to expected parturition (GD 21 for Crl:CD(SD) rats and GD 20 for Wistar rats). The gross necropsies included an examination and description of uterine contents including counts of corpora lutea, implantation sites, resorptions, and live and dead fetuses. All live fetuses were sexed, weighed, and examined externally and euthanized. Following euthanasia, fresh visceral and head examinations were performed on selected fetuses. The fetal carcasses were then processed and examined for skeletal

  15. Effects of two grading techniques of zirconia material on the fatigue limit of full-contour 3-unit fixed dental prostheses

    Science.gov (United States)

    Villefort, Regina Furbino; Amaral, Marina; Pereira, Gabriel Kalil Rocha; Campos, Tiago Moreira Bastos; Zhang, Yu; Bottino, Marco Antonio; Valandro, Luiz Felipe; de Melo, Renata Marques

    2017-01-01

    Objective This study evaluated the effects of two grading zirconia techniques on the fatigue limit of 3-unit fixed dental prostheses (FDPs). Methods Presintered blocks of 3Y-TZP were milled to obtain sixty-nine 3-unit FDPs, which were divided into three groups (n = 23). The control group (CTL) was sintered and glazed following manufacturer’s instructuctions. The two experimental groups presintered FDPs received a surface silica/glass infiltration treatment before the sintering process. Silica sol-gel group (SSG) was graded by the sol-gel processing route, while the glass-zirconia-glass group (GZG) was graded by an enameling technique. Graded groups did not receive a glaze layer after sintering. All FDPs were then luted with a dual-curing resin cement on composite abutments, embedded in polyurethane and stored in water for five days. The initial load of the fatigue test was calculated based on the results of the monotonic testing applied on three specimens of each group. To determine the fatigue limit, 20 samples of each group were subjected to staircase testing (100,000 cycles/5 Hz). Results The fatigue limits (in Newtons) were CTL = 1607.27, SSG = 1824.31, and GZG = 2006.57, and the Dixon and Mood test indicated statistically significant differences among groups (95% confidence interval). Significance The infiltration of silica and glass on bulk zirconia, by two different grading methods, increased the fatigue limits of monolithic zirconia FDPs. PMID:28118929

  16. Grade 6 Science Curriculum Specifications.

    Science.gov (United States)

    Alberta Dept. of Education, Edmonton. Curriculum Branch.

    This material describes curriculum specifications for grade 6 science in Alberta. Emphases recommended are: (1) process skills (50%); (2) psychomotor skills (10%); (3) attitudes (10%); and (4) subject matter (30%). Priorities within each category are identified. (YP)

  17. Interdisciplinary Student/Teacher Materials in Energy, the Environment, and the Economy: 3, Energy, Engines, and the Industrial Revolution, Grades 8, 9.

    Science.gov (United States)

    Childs, Barbara; And Others

    This instructional unit for grades 8-9 combines science and social studies in a look at the broad social and economic upheavals that took place during the industrial revolution, giving special emphasis to the role of energy. The invention and development of the steam engine is highlighted in one lesson. Other lessons show how the industrial…

  18. Health Curriculum Materials: Grades 7, 8, and 9. Strand IV, Environmental and Community Health; Consumer Health Education. Special Edition for Evaluation and Discussion.

    Science.gov (United States)

    Van Hooft, Gordon E.; And Others

    This publication contains curriculum suggestions for teaching Environmental and Community Health-Consumer Health, for grades seven, eight, and nine. Outcomes desired at this level include: 1) being aware of the practice of health quackery and being able to recognize those traits that characterize the health fraud, his techniques, and his products;…

  19. The Needs for Multicultural Knowledge in Instructional Material on Theme 7 "Beautiful Diversity in My Country" Grade 4th Elementary School

    Directory of Open Access Journals (Sweden)

    Latifatul Jannah

    2017-08-01

    Full Text Available The aims of research consist of the following (1 to know need analysis of Curriculum 2013 instructional materials in elementary school (2 to develop instructional material based on multicultural values.The study employs descriptive qualitative method which the data are collected by interview,  observation, and document analysis.The observation and interview results about instructional materials of Curriculum 2013 in some elementary school in Surakarta consist of the following (1 teachers need additional materials in order to deliver suitable material of Curriculum2013 for students. (2 teachers get difficulties in selecting suitable additional material. (3 teachers need additional material which can develop students good characters by adding Indonesian multicultural knowledge in all subjects. By enriching and developing multicultural values for students so it can be integrated in instructional materials such as tolerance, nationalism, and spirit of unity in diversities.

  20. Aerospace Grade Carbon Felt Preform, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Fiber Materials, Inc. (FMI) will develop an aerospace-grade carbon felt preform by employing application specific materials with effective processes and fabrication...

  1. On the thermal buckling of simply supported rectangular plates made of a sigmoid functionally graded Al/Al2O3 based material

    Science.gov (United States)

    Atmane, H. A.; Bedia, E. A. A.; Bouazza, M.; Tounsi, A.; Fekrar, A.

    2016-03-01

    We study the thermal buckling of a simply supported sigmoid functionally graded (SFGM) rectangular plate using first-order shear deformation theory. The S-FGM system consists of ceramic (Al2O3) and metal (Al) phases varying across the plate thickness according to a law described by two power-law functions. The effective properties of the composite are determined by the rule of mixtures, whose implementation is simpler than that of methods of micromechanics. The thermal heating is characterized by a uniform, linear, or sinusoidal temperature distribution across the plate thickness. The effects of the plate aspect ratio, the relative thickness, the gradient index, and the transverse shear on the buckling temperature difference are studied.

  2. FY17 Status Report on Testing Supporting the Inclusion of Grade 91 Steel as an Acceptable Material for Application of the EPP Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Messner, Mark C. [Argonne National Lab. (ANL), Argonne, IL (United States); Sham, Sam [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Yanli [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This report summarizes the experiments performed in FY17 on Gr. 91 steels. The testing of Gr. 91 has technical significance because, currently, it is the only approved material for Class A construction that is strongly cyclic softening. Specific FY17 testing includes the following activities for Gr. 91 steel. First, two types of key feature testing have been initiated, including two-bar thermal ratcheting and Simplified Model Testing (SMT). The goal is to qualify the Elastic – Perfectly Plastic (EPP) design methodologies and to support incorporation of these rules for Gr. 91 into the ASME Division 5 Code. The preliminary SMT test results show that Gr. 91 is most damaging when tested with compression hold mode under the SMT creep fatigue testing condition. Two-bar thermal ratcheting test results at a temperature range between 350 to 650o C were compared with the EPP strain limits code case evaluation, and the results show that the EPP strain limits code case is conservative. The material information obtained from these key feature tests can also be used to verify its material model. Second, to provide experimental data in support of the viscoplastic material model development at Argonne National Laboratory, selective tests were performed to evaluate the effect of cyclic softening on strain rate sensitivity and creep rates. The results show the prior cyclic loading history decreases the strain rate sensitivity and increases creep rates. In addition, isothermal cyclic stress-strain curves were generated at six different temperatures, and a nonisothermal thermomechanical testing was also performed to provide data to calibrate the viscoplastic material model.

  3. Student Attitudes Toward Grades and Grading Practices.

    Science.gov (United States)

    Stallings, William M.; Leslie, Elwood K.

    The result of a study designed to assess student attitudes toward grading practices are discussed. Questionnaire responses of 3439 students in three institutions were tabulated. Responses were generally negative toward conventional grading systems. (MS)

  4. Studies on the production of building material grade slag from hazardous-waste incineration plants; Untersuchungen zur Herstellung einer Schlacke mit Baustoffqualitaet aus Sondermuellverbrennungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Reich, J.; Herbel, J.D.; Pasel, C. [Duisburg Univ. (Gesamthochschule) (Germany). Fachgebiet Abfalltechnik

    1998-09-01

    In an attempt to restore the competitive power of hazardous-waste incineration within the present legal framework, plant operators have in some cases lowered disposal prices below the break-even point; in this respect there is no further room for improvement. One approach towards a new marketable solution could be to use rotary kilns not only for disposal but also as production plants. This could be achieved by means of input control and loading materials. If, for example, the slag remaining after combustion could be made to meet building material specifications, thus providing a marketable product, then rotary kilns would be able to serve as production plants for a secondary raw material. If it should prove possible in the course of manufacturing campaigns to develop slags from hazardous-waste incineration plants to a marketable product, then operators will thus have complied to the demand of the Law on Recycling and Waste Management for waste avoidance and that of the Emission Control Law for residue recycling. Targeted use of suitable loading materials for quality improvement could enable operators of hazardous-waste incineration plants to secure a new strategic position on the market as building material manufacturers and utilise existing plant capacities. [Deutsch] Um die Sonderabfallverbrennung im Rahmen der rechtlichen Vorgaben wieder konkurrenzfaehig zu machen, haben die Anlagenbetreiber die Entsorgungspreise teilweise unter die Grenze der Kostendeckung zurueckgenommen; hier besteht kein Spielraum mehr. Ein neuer, marktgerechter Ansatz koennte sich dann ergeben, wenn die Drehrohroefen statt als Beseitigungsaggregate durch Inputsteuerung und Zuschlaege eventuell auch als Produktionsanlagen einzusetzen waeren. Wenn z.B. die Schlacke, als Rueckstand aus der Verbrennung, als ein im Baustoffmarkt absetzbares Produkt nach Qualitaetskriterien gezielt hergestellt wuerde, koennte der Drehrohrofen als Produktionsanlage fuer einen Sekundaerrohstoff betrieben werden

  5. Choosing the Adequate Level of Graded Readers--Preliminary Study

    Science.gov (United States)

    Prtljaga, Jelena; Palinkaševic, Radmila; Brkic, Jovana

    2015-01-01

    Graded readers have been used as second language teaching material since the end of the Second World War. They are an important source of simplified material which provides comprehensible input on all levels. It is of crucial importance for a successful usage of graded readers in the classroom and in studies which focus on graded readers, that an…

  6. Mechanics of Graded Wrinkles

    Science.gov (United States)

    Raayai-Ardakani, Shabnam; Boyce, Mary

    2013-03-01

    Shark skin is known for its anti-fouling and self-cleaning properties. In attempts to mimic this pattern for getting similar properties, different surface patterns such as Sharklet and wrinkles have been previously introduced. Wrinkled patterns have gained importance in applications such as microfluidics, wetting and adhesion. Through buckling of a thin film of stiff material on a substrate of softer material, and maintaining symmetric geometries, ordered wrinkled patterns can be created. However, it can be shown that using the same principle, by changing the geometry of the surface, the dimensions of the wrinkles can be altered. This alteration turns ordered wrinkles into graded wrinkles which have more resemblance to shark skin than the ordered wrinkles, maintaining the same wave length while each wave having different amplitude. Here using finite element models, experiments and analytical solutions, the relations between different geometries and the resulting patterns were investigated.

  7. The effect of equal channel angular pressing on the tensile properties and microstructure of two medical implant materials: ASTM F-138 austenitic steel and Grade 2 titanium

    Science.gov (United States)

    Mendes Filho, A. de A.; Sordi, V. L.; Kliauga, A. M.; Ferrante, M.

    2010-07-01

    Titanium and F-138 stainless steel are employed in bone replacement and repair. The former material was ECAP-deformed at room temperature and at 300°C, followed in some cases by cold rolling. The steel was ECAP-deformed at room temperature only. Work-hardening behavior was studied by making use of the Kocks-mecking plots and microstructural evolution was followed by TEM. Conclusions show that for Ti, ECAP combined with cold rolling gives the best strength-ductility combination, whilst room temperature ECAP increases the tensile strength of the steel but caused substantial ductility loss.

  8. The effect of equal channel angular pressing on the tensile properties and microstructure of two medical implant materials: ASTM F-138 austenitic steel and Grade 2 titanium

    Energy Technology Data Exchange (ETDEWEB)

    Filho, A de A Mendes; Sordi, V L; Kliauga, A M; Ferrante, M, E-mail: ferrante@ufscar.b [Federal University of Sao Carlos, Materials Engineering Department, Sao Carlos, 13565-905 (Brazil)

    2010-07-01

    Titanium and F-138 stainless steel are employed in bone replacement and repair. The former material was ECAP-deformed at room temperature and at 300{sup 0}C, followed in some cases by cold rolling. The steel was ECAP-deformed at room temperature only. Work-hardening behavior was studied by making use of the Kocks-mecking plots and microstructural evolution was followed by TEM. Conclusions show that for Ti, ECAP combined with cold rolling gives the best strength-ductility combination, whilst room temperature ECAP increases the tensile strength of the steel but caused substantial ductility loss.

  9. Effects of Inhomogeneity and Thickness Parameters on the Elastic Response of a Pressurized Hyperbolic Annulus/Disc Made of Functionally Graded Material

    Directory of Open Access Journals (Sweden)

    Vebil Yıldırım

    2017-10-01

    Full Text Available A broad parametric study is carried out to investigate the effects of both the inhomogeneity parameter, and a profile index of Stodola’s hyperbolic function on the static response of such structures subjected to both the inner and outer pressures. The investigation is based on the analytical formulas lately published by the author. The effects of those parameters on the variation of the radial displacement, the radial and hoop stresses are all graphically illustrated for an annulus pressurized at its both surfaces. It is observed that, especially, the variation of the hoop stress in radial coordinate is closely sensible to variation of those parameters. For the chosen problems it was observed that one of two materials whose Young’s modulus is higher than the other is better to locate at the inner surface of the disc having divergent profile to get reasonable maximum hoop stresses. However much smaller radial displacements may be obtained by using positive inhomogeneity indexes for all discs whose surfaces host a material whose Young’s modulus is smaller than the other. To reach a final decision, analytical formulas such as those used in the present study together with a failure criteria such as Von Mises and Tresca become indispensable means in a design process.

  10. Asterisk Grade Study Report.

    Science.gov (United States)

    Kokorsky, Eileen A.

    A study was conducted at Passaic County Community College (PCCC) to investigate the operation of a grading system which utilized an asterisk (*) grade to indicate progress in a course until a letter grade was assigned. The study sought to determine the persistence of students receiving the "*" grade, the incidence of cases of students receiving…

  11. Surface mechanical properties, corrosion resistance, and cytocompatibility of nitrogen plasma-implanted nickel-titanium alloys: a comparative study with commonly used medical grade materials.

    Science.gov (United States)

    Yeung, K W K; Poon, R W Y; Chu, P K; Chung, C Y; Liu, X Y; Lu, W W; Chan, D; Chan, S C W; Luk, K D K; Cheung, K M C

    2007-08-01

    Stainless steel and titanium alloys are the most common metallic orthopedic materials. Recently, nickel-titanium (NiTi) shape memory alloys have attracted much attention due to their shape memory effect and super-elasticity. However, this alloy consists of equal amounts of nickel and titanium, and nickel is a well known sensitizer to cause allergy or other deleterious effects in living tissues. Nickel ion leaching is correspondingly worse if the surface corrosion resistance deteriorates. We have therefore modified the NiTi surface by nitrogen plasma immersion ion implantation (PIII). The surface chemistry and corrosion resistance of the implanted samples were studied and compared with those of the untreated NiTi alloys, stainless steel, and Ti-6Al-4V alloy serving as controls. Immersion tests were carried out to investigate the extent of nickel leaching under simulated human body conditions and cytocompatibility tests were conducted using enhanced green fluorescent protein mice osteoblasts. The X-ray photoelectron spectroscopy results reveal that a thin titanium nitride (TiN) layer with higher hardness is formed on the surface after nitrogen PIII. The corrosion resistance of the implanted sample is also superior to that of the untreated NiTi and stainless steel and comparable to that of titanium alloy. The release of nickel ions is significantly reduced compared with the untreated NiTi. The sample with surface TiN exhibits the highest amount of cell proliferation whereas stainless steel fares the worst. Compared with coatings, the plasma-implanted structure does not delaminate as easily and nitrogen PIII is a viable way to improve the properties of NiTi orthopedic implants.

  12. Processing of W-Cu functionally graded materials (FGM) through the powder metallurgy route: application as plasma facing components for ITER-like thermonuclear fusion reactor; Elaboration de materiaux W-Cu a gradient de proprietes fonctionnelles (FGM) par metallurgie des poudres: application en tant que composants face au plasma de machines de fusion thermonucleaire de type Iter

    Energy Technology Data Exchange (ETDEWEB)

    Raharijaona, J.J.

    2009-11-15

    The aim of this study was to study and optimize the sintering of W-Cu graded composition materials, for first wall of ITER-like thermonuclear reactor application. The graded composition in the material generates graded functional properties (Functionally Graded Materials - FGM). Rough thermomechanical calculations have shown the interest of W-Cu FGM to improve the lifetime of Plasma Facing Components (PFC). To process W-Cu FGM, powder metallurgy route was analyzed and optimized from W-CuO powder mixtures. The influence of oxide reduction on the sintering of powder mixtures was highlighted. An optimal heating treatment under He/H{sub 2} atmosphere was determined. The sintering mechanisms were deduced from the analysis of the effect of the Cu-content. Sintering of W-Cu materials with a graded composition and grain size has revealed two liquid migration steps: i) capillary migration, after the Cu-melting and, ii) expulsion of liquid, at the end of sintering, from the dense part to the porous part, due to the continuation of W-skeleton sintering. These two steps were confirmed by a model based on capillary pressure calculation. In addition, thermal conductivity measurements were conducted on sintered parts and showed values which gradually increase with the Cu-content. Hardness tests on a polished cross-section in the bulk are consistent with the composition profiles obtained and the differential grain size. (author)

  13. Asymmetric acoustic transmission in graded beam

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Li, E-mail: lj94172350@hotmail.com [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Wu, Jiu Hui, E-mail: ejhwu@mail.xjtu.edu.cn [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Guan, Dong; Lu, Kuan [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Gao, Nansha [School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Songhua, Cao [School of Mechanical Engineering and State Key laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-12-01

    We demonstrate the dynamic effective material parameters and vibration performance of a graded beam. The structure of the beam was composed of several unit cells with different fill factors. The dispersion relations and energy band structures of each unit cell were calculated using the finite element method (FEM). The dynamic effective material parameters in each unit cell of the graded beam were determined by the dispersion relations and energy band structures. Longitudinal wave propagation was investigated using a numerical method and FEM. The results show that the graded beam allows asymmetric acoustic transmission over a wide range of frequencies.

  14. Gleason grading system

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000920.htm Gleason grading system To use the sharing features on this page, ... score of between 5 and 7. Gleason Grading System Sometimes, it can be hard to predict how ...

  15. Biology Grade 10, Science Curriculum Materials.

    Science.gov (United States)

    Bloom, Samuel W.

    This teaching guide and syllabus outline is intended for use with pupils whose primary interests are in non-science fields, or who do not intend to enter college. The guide contains suggested activities, both laboratory and discussion, for a course containing the following sections: Introduction to Cells and Life; Animal Physiology; Plant…

  16. Colorado Student Assessment Program: 2001 Released Passages, Items, and Prompts. Grade 4 Reading and Writing, Grade 4 Lectura y Escritura, Grade 5 Mathematics and Reading, Grade 6 Reading, Grade 7 Reading and Writing, Grade 8 Mathematics, Reading and Science, Grade 9 Reading, and Grade 10 Mathematics and Reading and Writing.

    Science.gov (United States)

    Colorado State Dept. of Education, Denver.

    This document contains released reading comprehension passages, test items, and writing prompts from the Colorado Student Assessment Program for 2001. The sample questions and prompts are included without answers or examples of student responses. Test materials are included for: (1) Grade 4 Reading and Writing; (2) Grade 4 Lectura y Escritura…

  17. Engaging in Argument from Evidence and the Ocean Sciences Sequence for Grades 3-5: A case study in complementing professional learning experiences with instructional materials aligned to instructional goals

    Science.gov (United States)

    Schoedinger, S. E.; Weiss, E. L.

    2016-12-01

    K-5 science teachers, who often lack a science background, have been tasked with a huge challenge in implementing NGSS—to completely change their instructional approach from one that views science as a body of knowledge to be imparted to one that is epistemic in nature. We have found that providing high-quality professional learning (PL) experiences is often not enough and that teachers must have instructional materials that align with their instructional goals. We describe a case study in which the Lawrence Hall of Science (the Hall) used the Hall-developed Ocean Sciences Sequence for Grades 3-5 (OSS 3-5) to support a rigorous PL program for grade 3-5 teachers focused on the NGSS science and engineering practice, engaging in argument from evidence. Developed prior to the release of NGSS, the Ocean Literacy Framework and the NGSS precursor, A Framework for K-12 Science Education, informed the content and instructional approaches of OSS 3-5. OSS 3-5 provides a substantial focus on making evidence-based explanations (and other science practices), while building students' ocean sciences content knowledge. From 2013-2015, the Hall engaged cohorts of teachers in a rigorous PL experience focused on engaging in argument from evidence. During the summer, teachers attended a week-long institute, in which exemplar activities from OSS 3-5 were used to model instructional practices to support arguing from evidence and related practices, e.g., developing and using models and constructing explanations. Immediately afterward, teachers enacted what they'd learned during a two-week summer school practicum. Here, they team-taught the OSS 3-5 curriculum, participated in video reflection groups, and received coaching and just-in-time input from instructors. In the subsequent academic year, many teachers began by teaching OSS 3-5 so that they could practice engaging students in argumentation in curriculum they'd already used for that purpose. Throughout the year, teachers

  18. High temperature thermo-physical properties of SPS-ed W–Cu functional gradient materials

    Science.gov (United States)

    Galatanu, Magdalena; Enculescu, Monica; Galatanu, Andrei

    2018-02-01

    The divertor of a fusion reactor like DEMO requires materials able to withstand high heat fluxes and neutron irradiation for several years. For the water cooling concept of this essential part of the reactor, the most likely plasma facing material will be W, while the heatsink material considered is CuCrZr or an improved version of such a Cu-based alloy. To realize W–Cu alloy joints able to withstand thousands of thermal cycles can be difficult due to the difference between the thermal expansion coefficients of these materials. In this work we investigate the possibility to realize such joints by using W–Cu functional gradient materials (FGMs) produced from nanometric and micrometric metallic powders mixtures and consolidated by spark plasma sintering at about 900 °C. Morphological and thermal properties investigations, performed for typical compositions, shows that the best results are obtained using powders with micrometric dimensions. A resulting 1 mm thick, 3 layers W–Cu FGM produced by this simple method shows a remarkable almost constant thermal conductivity value of 200 W m‑1 K‑1, from room temperature up to 1000 °C.

  19. The Effect Of Ceramic In Combination Of Two Sigmoid Functionally Graded Rotating Disks With Variable Thickness

    DEFF Research Database (Denmark)

    Bayat, M.; Sahari, B. B.; Saleem, M.

    2012-01-01

    In this paper the elastic solutions of a disk composed of FGM – Functionaly Graded Material, is presented.......In this paper the elastic solutions of a disk composed of FGM – Functionaly Graded Material, is presented....

  20. Graded Density Carbon Bonded Carbon Fiber (CBCF) Preforms for Lightweight Ablative Thermal Protection Systems (TPS), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — FMI has developed graded density CBCF preforms for graded density phenolic impregnated carbon ablator (PICA) material to meet NASA's future exploration mission...

  1. Numerical Evaluations of Functionally Graded RC Slabs

    Directory of Open Access Journals (Sweden)

    M. Mastali

    2014-01-01

    Full Text Available Nowadays, using fibrous materials is used widely in strengthening applications such as cross-section enlargement and using functionally graded reinforced concrete. Functionally graded reinforced concrete is used as multireinforced concrete layers that can be reinforced by different fiber types. The objective of this research was to address the structural benefits of functionally graded concrete materials by performing analytical simulations. In order to achieve this purpose, in the first stage of this study, three functionally graded reinforced concretes by steel and polypropylene (PP were experimentally tested under flexural loading. Inverse analysis was applied to obtain the used material properties of reinforced concrete by FEMIX software. After obtaining the material properties, to assess the performance of proposed slabs, some other cases were proposed and numerically evaluated under flexural and shear loading. The results showed that increasing steel fiber in reinforced entire cross section led to achieve better shear and flexural performance while the best performance of reinforced functionally graded slabs was achieved for slab at 1% fiber content. In the second stage, nineteen reinforced functionally graded RC slabs with steel bars were simulated and assessed and some other cases were considered which were not experimentally tested.

  2. Dynamics of graded-composition and graded-doping semiconductor nanowires under local carrier modulation.

    Science.gov (United States)

    Deng, Wenjuan; Zou, Jijun; Peng, Xincun; Zhang, Jianbing; Wang, Weilu; Zhang, Yijun; Zhang, Daoli

    2016-10-17

    Scanning photocurrent microscopy is a powerful tool for investigating charge transfer and internal fields, which strongly influence carrier statics and dynamics in semiconductor nanowires. We performed comprehensive numerical modeling of the carrier dynamics of graded-composition and graded-doping AlGaAs nanowires to achieve a greater understanding of these nanowires. The simulation results indicated that the built-in electric field changes the shape of the scanning photocurrent microscopy profiles, which helped us to judge the dopant level, Al composition range and doping type of the material. The simulation results also assess the potential of the scanning photocurrent techniques in graded-doping and graded-composition nanowire properties.

  3. Robinson′s cytological grading on aspirates of breast carcinoma: Correlation with Bloom Richardson′s histological grading

    Directory of Open Access Journals (Sweden)

    Sinha S

    2009-01-01

    Full Text Available Background : Cytological grading (CG on aspirates of breast carcinoma is a useful tool for surgical maneuver and prognosis. Aims : An endeavor was made to use CG on aspirates of breast carcinoma using Robinson′s grade and to correlate it with Bloom Richardsons′ histopathological grading. Materials and Methods : A total of 59 patients of breast carcinoma, aged 28-57 years, were aspirated and the smears were graded using Robinson′s criteria. All the cases were correlated with Bloom Richardson′s grade on histopathology in mastectomy specimens. Lymphadenopathy in 38 cases was aspirated and stained with Papanicolaou and Romanowsky stain. Results : Robinson′s CG correlated well with Bloom Richardson′s histopathological grading. For grade I and II tumors, there was substantial strength of agreement between cytology and histopathology, while in grade III, the concordance was nearly perfect. Lymph node metastasis was found in 27 of 32 axillary nodes, three of five cervical nodes and the only palpable supraclavicular node. Lymph node metastasis was observed in three with cytological grade II, 28 of grade III and none of grade I. All grade I had stage A, two of grade II had stage B, while all grade III had either stage B or stage C disease. Conclusions : Thus, CG of breast carcinoma correlates well with histopathological grading and may well be useful as a prognostic marker.

  4. Fabrication of functionally gradient materials with internal channels in ceramics and ceramic composites

    Science.gov (United States)

    Shin, Hyea-Weon

    Functionally Gradient Materials (FGMs) are inhomogeneous materials whose compositions vary from one phase to another. By tailoring the inhomogeneous properties, FGMs can be used to reduce the stresses that are caused by severe thermal gradients. Thermal gradient loading can further be compensated by heat transfer into a cooling fluid circulating in a network of channels and manifolds. In an envisioned application, heat from a localized source is transferred to the cooling fluid, easing sharp thermal loads while minimizing the unwanted spread of heat energy to the ambient surroundings. This study reports on the fabrication of functionally gradient ceramics and the embedding of simple internal channels within these ceramics. Functional gradiency (variation of composition) is built in via the layering of different components across the thickness of a plate sample. Traditional powder processing techniques are applied to fabricate the test pieces, and recently developed methods of joining are used to build assemblies from individually sintered plate layers. For a well-formed FGM to be made, materials parameters need to be selected based on mechanical, thermal and chemical properties. As a class, ceramics are hard, wear-resistant, refractory, electrically and thermally insulative, nonmagnetic, chemically stable, and oxidation-resistant. However, because of their brittleness, ceramics with minute channels are difficult to machine. Instead, for this study, a graphite fugitive phase is used as a spacer to support channel volumes within a ceramic powder compact; during pre-sintering, the graphite burns out to expose a network of channels. Full sintering fixes the final shape. At the operating temperatures of the ovens used in our fabrication study, sintering of alumina, partially stabilized zirconia, fully stabilized zirconia and hydroxyapatite have been successful, and these ceramic powders form the basis of the present fabrication studies. Inhomogeneities inherent in the

  5. Nonlinear Vibration of the Cantilever FGM Plate Based on the Third-order Shear Deformation Plate Theory

    Science.gov (United States)

    Hao, Y. X.; Zhang, W.

    2010-05-01

    The present investigation focuses on the research of the nonlinear vibration of a cantilevered FGMs rectangular plate subjected to the transversal excitation. Materials properties of the constituents are graded in the thickness direction according to a power law distribution and are assumed to be temperature-dependent and vary along the thickness direction. In the framework of the Reddy's Third-order shear deformation plate theory, the governing equations of motion for the cantilever FGMs rectangular plate are derived by using the Hamilton's principle. The thermal effect due to one-dimensional temperature gradient is included in the analysis. The equations of motion can be reduced two-degree-of-freedom nonlinear system under the external excitations using the Galerkin's method. Using numerical method, the control equations are analyzed to obtain the response curves. A detailed parametric study is conducted to show the influences of the material properties on dynamic responses of the nonlinear vibration of the cantilever FGM plate.

  6. Spectral finite element method wave propagation, diagnostics and control in anisotropic and inhomogeneous structures

    CERN Document Server

    Gopalakrishnan, Srinivasan; Roy Mahapatra, Debiprosad

    2008-01-01

    The use of composites and Functionally Graded Materials (FGMs) in structural applications has increased. FGMs allow the user to design materials for a specified functionality and have many uses in structural engineering. However, the behaviour of these structures under high-impact loading is not well understood. This book is the first to apply the Spectral Finite Element Method (SFEM) to inhomogeneous and anisotropic structures in a unified and systematic manner. It focuses on some of the problems with this media which were previously thought unmanageable. Types of SFEM for regular and damaged 1-D and 2-D waveguides, solution techniques, methods of detecting the presence of damages and their locations, and methods for controlling the wave propagation responses are discussed. Tables, figures and graphs support the theory and case studies are included. This book is of value to senior undergraduates and postgraduates studying in this field, and researchers and practicing engineers in structural integrity.

  7. Power calculation of grading device in desintegrator

    Science.gov (United States)

    Bogdanov, V. S.; Semikopenko, I. A.; Vavilov, D. V.

    2018-03-01

    This article describes the analytical method of measuring the secondary power consumption, necessitated by the installation of a grading device in the peripheral part of the grinding chamber in the desintegrator. There is a calculation model for defining the power input of the disintegrator increased by the extra power demand, required to rotate the grading device and to grind the material in the area between the external row of hammers and the grading device. The work has determined the inertia moments of a cylindrical section of the grading device with armour plates. The processing capacity of the grading device is adjusted to the conveying capacity of the auger feeder. The grading device enables one to increase the concentration of particles in the peripheral part of the grinding chamber and the amount of interaction between particles and armour plates as well as the number of colliding particles. The perforated sections provide the output of the ground material with the proper size granules, which together with the effects of armour plates, improves the efficiency of grinding. The power demand to rotate the grading device does not exceed the admissible value.

  8. Vascular grading of angiogenesis

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Sørensen, Flemming Brandt

    2000-01-01

    The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11...... was moderately reproduced (kappa = 0.59). Vascular grade was significantly associated with axillary node involvement, tumour size, malignancy grade, oestrogen receptor status and histological type. In univariate analyses vascular grade significantly predicted recurrence free survival and overall survival for all...... impact for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer....

  9. Graded tensor calculus

    International Nuclear Information System (INIS)

    Scheunert, M.

    1982-10-01

    We develop a graded tensor calculus corresponding to arbitrary Abelian groups of degrees and arbitrary commutation factors. The standard basic constructions and definitions like tensor products, spaces of multilinear mappings, contractions, symmetrization, symmetric algebra, as well as the transpose, adjoint, and trace of a linear mapping, are generalized to the graded case and a multitude of canonical isomorphisms is presented. Moreover, the graded versions of the classical Lie algebras are introduced and some of their basic properties are described. (orig.)

  10. Learning from Graded Readers.

    Science.gov (United States)

    Wodinsky, Marilyn; Nation, Paul

    1988-01-01

    A word frequency study of two graded readers and an unsimplified text indicated that graded readers facilitated better foreign-language reading and vocabulary learning than did unsimplified texts. It was found that students needed to read several same-level texts to master vocabulary, and that vocabulary mastery was not necessary for successful…

  11. Structural kinematics based damage zone prediction in gradient structures using vibration database

    Science.gov (United States)

    Talha, Mohammad; Ashokkumar, Chimpalthradi R.

    2014-05-01

    To explore the applications of functionally graded materials (FGMs) in dynamic structures, structural kinematics based health monitoring technique becomes an important problem. Depending upon the displacements in three dimensions, the health of the material to withstand dynamic loads is inferred in this paper, which is based on the net compressive and tensile displacements that each structural degree of freedom takes. These net displacements at each finite element node predicts damage zones of the FGM where the material is likely to fail due to a vibration response which is categorized according to loading condition. The damage zone prediction of a dynamically active FGMs plate have been accomplished using Reddy's higher-order theory. The constituent material properties are assumed to vary in the thickness direction according to the power-law behavior. The proposed C0 finite element model (FEM) is applied to get net tensile and compressive displacement distributions across the structures. A plate made of Aluminum/Ziconia is considered to illustrate the concept of structural kinematics-based health monitoring aspects of FGMs.

  12. Graded coatings for thermal, wear and corrosion barriers

    International Nuclear Information System (INIS)

    Schulz, U.; Peters, M.; Bach, Fr.-W.; Tegeder, G.

    2003-01-01

    The present paper summarizes the main results generated in a German National Science Foundation (DFG) program on projects concerned with functionally graded materials applied to optimize the thermal, wear and corrosion properties of metallic and ceramic materials. Thermal barrier coatings deposited onto Cu substrates by pulsed laser deposition showed improved spallation behavior by a graded lamella microstructure with improved interface fracture toughness. A particle-hardened graded surface structure improved the wear resistance of plasma sprayed thermal barriers. By means of evaporation techniques a graded bonding area was manufactured with a high potential of lifetime improvement. For non-oxide ceramics graded coatings based on Si 3 N 4 and mullite led to improved oxidation resistance of the substrate material. Graded TiC-TiN thin films allowed to improve the wear resistance of cutting tool alloys with good adhesion to the substrate material. On light metal alloys, the limits of grading with respect to corrosion protection as well as wear were determined. Graded layers of arc-sprayed titanium with in situ produced particles or welded alloy gradients led to improved wear characteristics. Stress profiles in graded layers were analyzed with the help of a modified X-ray diffraction analysis

  13. [Crops: Classifying, Selecting, Harvesting, Grading, and Packing.] Student Materials. V.A. III. [IV-B-1 through IV-B-2; IV-C-1 through IV-C-2].

    Science.gov (United States)

    Texas A and M Univ., College Station. Vocational Instructional Services.

    Part of a series of eight student learning modules in vocational agriculture, this booklet deals with crop-related activities. The first section is on harvesting methods and equipment. The following portions address the handling, grading, and packing of crops; and the classification and selection of fruits, vegetables, and ornamental plants. There…

  14. Clinical performance of a human papillomavirus messenger RNA test (Aptima HPV Assay) on residual material from archived 3-year-old PreservCyt samples with low-grade squamous intraepithelial lesion

    DEFF Research Database (Denmark)

    Waldstrøm, Marianne; Ornskov, Dorthe

    2011-01-01

    Human papillomavirus (HPV) testing is widely used in the triage of women with a borderline smear result but the efficiency of testing women with low-grade squamous intraepithelial lesion (LSIL) is less clear, mainly because of lack of specificity. New HPV tests are emerging, which detect E6/E7...

  15. What Can Readers Read after Graded Readers?

    Science.gov (United States)

    McQuillan, Jeff

    2016-01-01

    Nation (2014) concluded that most of the vocabulary one needs to read challenging texts in English can be acquired incidentally through voluminous reading. This study examines possible texts that second language (L2) readers can use to move from controlled-vocabulary materials such as graded readers, which go up through approximately the…

  16. Seismic performance of circular reinforced concrete bridge columns constructed with grade 80 reinforcement.

    Science.gov (United States)

    2014-08-01

    This project assessed the use of ASTM A706 Grade 80 reinforcing bars in reinforced concrete columns. : Grade 80 is not currently allowed in reinforced concrete columns due to lack of information on the : material characteristics and column performanc...

  17. Nonlinear properties of a graded-index photonic heterostructure

    Indian Academy of Sciences (India)

    Abstract. The optical properties of a one-dimensional (1D) photonic heterostructure with graded- index nonlinear materials are demonstrated theoretically. The influence of the gradation profile of the graded-index nonlinear layers on the linear and nonlinear responses of the structure are analysed. It is shown that the ...

  18. Methods of graded rings

    CERN Document Server

    Nastasescu, Constantin

    2004-01-01

    The topic of this book, graded algebra, has developed in the past decade to a vast subject with new applications in noncommutative geometry and physics. Classical aspects relating to group actions and gradings have been complemented by new insights stemming from Hopf algebra theory. Old and new methods are presented in full detail and in a self-contained way. Graduate students as well as researchers in algebra, geometry, will find in this book a useful toolbox. Exercises, with hints for solution, provide a direct link to recent research publications. The book is suitable for courses on Master level or textbook for seminars.

  19. Report on the results of the fiscal 1997 international research cooperation project. `Joint R and D industrial base technology` (development of functionally graded materials); 1997 nendo kokusai kyoryoku jigyo. `Sangyo kiban gijutsu kyodo kenkyu kaihatsu` keisha kinosei zairyo no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    For the purpose of developing functionally graded materials (FGM/LB) of thermal stress relaxation heat resistant large bulk state which are adoptable to high efficiency engine members, conducted in fiscal 1997 as intermediate target were the experiment for enlargement of the sintering process of FGM/LB with bore of up to 100mm, evaluation of physical properties, the basic development of the fabricating system facility for the commercialization. In the development of heat resistance use FGM/LB fabrication technology, to obtain ZrO2(3Y) stainless steel system FGM/LB, the following were fabricated in each bore size of 50-100mm by the research use large discharge plasma sintering machine: sintered bodies of ceramics/metal single substrate materials and mixed layer single substance materials, and FGM/LB sintered bodies without separation and crack which are composed of 9 intermediate graded layers. The survey was also made on the optimal composition and optimal sintering conditions toward the enlargement without unevenness. In the evaluation of physical properties, ZrO2(3Y)/stainless steel system was selected and test pieces were fabricated to obtain basic data on texture observation, distribution of hardness, fracture toughness, high temperature abrasion resistance, thermal expansion rates, etc. 27 refs., 108 figs., 43 tabs.

  20. Graded bandgap perovskite solar cells

    Science.gov (United States)

    Ergen, Onur; Gilbert, S. Matt; Pham, Thang; Turner, Sally J.; Tan, Mark Tian Zhi; Worsley, Marcus A.; Zettl, Alex

    2017-05-01

    Organic-inorganic halide perovskite materials have emerged as attractive alternatives to conventional solar cell building blocks. Their high light absorption coefficients and long diffusion lengths suggest high power conversion efficiencies, and indeed perovskite-based single bandgap and tandem solar cell designs have yielded impressive performances. One approach to further enhance solar spectrum utilization is the graded bandgap, but this has not been previously achieved for perovskites. In this study, we demonstrate graded bandgap perovskite solar cells with steady-state conversion efficiencies averaging 18.4%, with a best of 21.7%, all without reflective coatings. An analysis of the experimental data yields high fill factors of ~75% and high short-circuit current densities up to 42.1 mA cm-2. The cells are based on an architecture of two perovskite layers (CH3NH3SnI3 and CH3NH3PbI3-xBrx), incorporating GaN, monolayer hexagonal boron nitride, and graphene aerogel.

  1. MOOC and mechanized grading

    OpenAIRE

    Queinnec, Christian

    2013-01-01

    4 pages; As many others, we too are developping a Massive Online Open Course or MOOC. This MOOC will teach recursive programming for beginnners and makes an heavy use of an already existing infrastructure for mechanical grading. This paper presents some ideas on how to combine these two components along with some (untested) incentives in order to increase students' involvement.

  2. Grades as Information

    Science.gov (United States)

    Grant, Darren

    2007-01-01

    We determine how much observed student performance in microeconomics principles can be attributed, inferentially, to three kinds of student academic "productivity," the instructor, demographics, and unmeasurables. The empirical approach utilizes an ordered probit model that relates student performance in micro to grades in prior…

  3. Purpose-Driven Grading

    Science.gov (United States)

    Carlson, Jane A. K.; Kimpton, Ann

    2010-01-01

    Allowing students to improve their grade by revising their written work may help students learn to revise, but it gives them no incentive to turn in quality work from the start. This article proposes a way to invert the process, thereby teaching students how to revise, while enforcing a more disciplined approach to good writing. (Contains 3…

  4. Cutting Class Harms Grades

    Science.gov (United States)

    Taylor, Lewis A., III

    2012-01-01

    An accessible business school population of undergraduate students was investigated in three independent, but related studies to determine effects on grades due to cutting class and failing to take advantage of optional reviews and study quizzes. It was hypothesized that cutting classes harms exam scores, attending preexam reviews helps exam…

  5. Endangered Animals. Second Grade.

    Science.gov (United States)

    Popp, Marcia

    This second grade teaching unit centers on endangered animal species around the world. Questions addressed are: What is an endangered species? Why do animals become extinct? How do I feel about the problem? and What can I do? Students study the definition of endangered species and investigate whether it is a natural process. They explore topics…

  6. Grading Classroom Participation.

    Science.gov (United States)

    Bean, John C.; Peterson, Dean

    1998-01-01

    Grading class participation can send positive signals to college students about the kind of learning and thinking an instructor values. Various structures for participation (whole-class discussion, cold-calling on students, collaborative learning, electronic mail, journals, student-faculty conferences) call for different approaches to assessment.…

  7. Thermal performance of functionally graded parabolic annular fins having constant weight

    Energy Technology Data Exchange (ETDEWEB)

    Gaba, Vivek Kumar; Tiwari, Anil Kumar; Bhowmick, Shubhankar [National Institute of Technology Raipur, Raipur (India)

    2014-10-15

    The proposed work reports the performance of parabolic annular fins of constant weight made of functionally graded materials. The work involves computation of temperature gradient, efficiency and effectiveness of such fins and compares the performances for different functionally graded parabolic fin profiles obtained by varying grading parameters and profile parameters respectively keeping the weight of the fins constant. The functional grading of thermal conductivity is based on a power function of radial co-ordinate which consists of parameters, namely grading parameters, varying which different grading combinations are studied. A general second order ordinary differential equation has been derived for all the profiles and material grading. The efficiency and effectiveness of the annular fins of different profile and grading combinations have been calculated and plotted and the results reveal the dependence of fin performance on profile and grading parameter.

  8. Production of Food Grade Yeasts

    Directory of Open Access Journals (Sweden)

    Argyro Bekatorou

    2006-01-01

    Full Text Available Yeasts have been known to humans for thousands of years as they have been used in traditional fermentation processes like wine, beer and bread making. Today, yeasts are also used as alternative sources of high nutritional value proteins, enzymes and vitamins, and have numerous applications in the health food industry as food additives, conditioners and flavouring agents, for the production of microbiology media and extracts, as well as livestock feeds. Modern scientific advances allow the isolation, construction and industrial production of new yeast strains to satisfy the specific demands of the food industry. Types of commercial food grade yeasts, industrial production processes and raw materials are highlighted. Aspects of yeast metabolism, with respect to carbohydrate utilization, nutritional aspects and recent research advances are also discussed.

  9. Cafeteria-Style Grading in General Chemistry

    Science.gov (United States)

    Goodwin, John A.; Gilbert, Brian D.

    2001-04-01

    Self-selected individual course-grade weighting schemes allow students personal choice of course components in the general chemistry sequence at Coastal Carolina University. With the availability of a wide range of commercial and academically produced pedagogical resources, students can select materials that best suit their own learning styles, social situations, and motivation level. Our students use a signed contract to indicate their preferred grade-weighting schemes for determination of the course grade. In doing so, they choose from course components that include peer-led team learning (PLTL) in the Workshop Chemistry (WSC) model, computer-assisted instruction (CAI) using the ChemSkill Builder (CSB) software, a variety of in-class quizzes and group problem-solving exercises, written exams, and the final written exam. Minimum percentage values are required of all components except WSC and CSB, which have been completely optional graded course components at CCU since the summer of 1999. Comparison of student success in the course and content learning suggests that the improvements observed with introduction of a gamut of activities increase even more when the cafeteria-style grading is implemented.

  10. Material Development and Meeting Learner's Need

    Science.gov (United States)

    Aydin, Abdullah

    2013-01-01

    In this study, the aim was to show that learners' needs can be met using simple and cheap materials that can be found everywhere in 9th to 11th grade Chemistry courses. To this end, materials were developed using simple everyday life materials for 9th to 11th grade Chemistry courses. In the research, the project method was employed. The study was…

  11. Determinants for grading Malaysian rice

    Science.gov (United States)

    ChePa, Noraziah; Yusoff, Nooraini; Ahmad, Norhayati

    2016-08-01

    Due to un-uniformity of rice grading practices in Malaysia, zones which actively producing rice in Malaysia are using their own way of grading rice. Rice grading is important in determining rice quality and its subsequent price in the market. It is an important process applied in the rice production industry with the purpose of ensuring that the rice produced for the market meets the quality requirements of consumer. Two important aspects that need to be considered in determining rice grades are grading technique and determinants to be used for grading (usually referred as rice attributes). This article proposes the list of determinants to be used in grading Malaysian rice. Determinants were explored through combination of extensive literature review and series of interview with the domain experts and practitioners. The proposed determinants are believed to be beneficial to BERNAS in improving the current Malaysian rice grading process.

  12. Buckling Response of Thick Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    BOUAZZA MOKHTAR

    2014-11-01

    Full Text Available In this paper, the buckling of a functionally graded plate is studied by using first order shear deformation theory (FSDT. The material properties of the plate are assumed to be graded continuously in the direction of thickness. The variation of the material properties follows a simple power-law distribution in terms of the volume fractions of constituents. The von Karman strains are used to construct the equilibrium equations of the plates subjected to two types of thermal loading, linear temperature rise and gradient through the thickness are considered. The governing equations are reduced to linear differential equation with boundary conditions yielding a simple solution procedure. In addition, the effects of temperature field, volume fraction distributions, and system geometric parameters are investigated. The results are compared with the results of the no shear deformation theory (classic plate theory, CPT.

  13. Let's End the Grading Game.

    Science.gov (United States)

    Edwards, Clifford H.; Edwards, Laurie

    1999-01-01

    Argues that grades have negative effects on learning and self-concept. States that while grading has a long tradition of sorting children for college entrance, there is limited evidence that grades serve a valid purpose. Argues that this practice should be abolished and an evaluation system established that provides a more valid estimate of…

  14. The Implications of Grade Inflation

    DEFF Research Database (Denmark)

    Smith, David E.; Fleisher, Steven

    2011-01-01

    The authors review current and past practices of the grade inflation controversy and present ways to return to each institution’s established grading guidelines. Students are graded based on knowledge gathered. Certain faculty members use thorough evaluative methods, such as written and oral...

  15. Axisymmetrical analysis of functionally graded circular piezoelectric plate by graded element using MATLAB

    Science.gov (United States)

    Shao, B. L.; Xu, R. Q.

    2009-07-01

    Circular piezoelectric bimorph has been successfully used in numerous types of microdevices, such as actuators for flowcontrol applications, transducers for acoustic applications, and in locomotion of robotic systems, energy harvesting and active structural health monitoring applications. Recently, the concept of the functionally graded material (FGM) is introduced to improve properties and increase lifetime by selectively grading the elastic, piezoelectric, and/or dielectric properties along the thickness of a piezoceramic. However, even for the simple case of homogeneous circular piezoelectric geometry, analytical treatments are severely limited. This study established an axisymmetric and isoparametric graded element to model the functionally graded circular piezoelectric plates. All the material properties including elastic coefficients, piezoelectric coefficients, dielectric parameters and mass density are graded in the element and interpolated using the shape functions, which is also used to render the displacements and electric potential distribution in the element. Both static and dynamic cases can be considered in this element. MATLAB is used to implement the whole FEM code and gives some numerical examples to demonstrate the presented method.

  16. New Method of Solar Grade Silicon Production

    Energy Technology Data Exchange (ETDEWEB)

    Zadde, V. V.; Pinov, A. B.; Strebkov, D. S.; Belov, E. P.; Efimov, N. K.; Lebedev, E. N.; Korobkov, E. I.; Blake, D.; Touryan, K.

    2002-08-01

    One of the main advantages of photovoltaic solar cells (PVC) is their ecological clarity of direct conversion of solar energy to electricity. For wide spreading of PV technologies it is necessary to ensure that there is no environment pollution at the stage of PVC-s manufacturing, beginning from producing of polysilicon feedstock. The objective of this project is creation of ecologically clean method for production of solar grade polysilicon feedstock (SGPF) as raw material for PVCs, and also raw material for producing monocrystalline silicon, which is used in electronic industry.

  17. Improvement of ASME NH for Grade 91

    Energy Technology Data Exchange (ETDEWEB)

    Bernard Riou

    2007-10-09

    This report has been prepared in the context of Task 3 of the ASME/DOE Gen IV material project. It has been identified that creep-fatigue evaluation procedures presently available in ASME (1) and RCC-MR (2) have been mainly developed for austenitic stainless steels and may not be suitable for cyclic softening materials such as mod 9 Cr 1 Mo steel (grade 91). The aim of this document is, starting from experimental test results, to perform a review of the procedures and, if necessary, provide recommendations for their improvements.

  18. Automated tone grading of granite

    International Nuclear Information System (INIS)

    Catalina Hernández, J.C.; Fernández Ramón, G.

    2017-01-01

    The production of a natural stone processing plant is subject to the intrinsic variability of the stone blocks that constitute its raw material, which may cause problems of lack of uniformity in the visual appearance of the produced material that often triggers complaints from customers. The best way to tackle this problem is to classify the product according to its visual features, which is traditionally done by hand: an operator observes each and every piece that comes out of the production line and assigns it to the closest match among a number of predefined classes, taking into account visual features of the material such as colour, texture, grain, veins, etc. However, this manual procedure presents significant consistency problems, due to the inherent subjectivity of the classification performed by each operator, and the errors caused by their progressive fatigue. Attempts to employ automated sorting systems like the ones used in the ceramic tile industry have not been successful, as natural stone presents much higher variability than ceramic tiles. Therefore, it has been necessary to develop classification systems specifically designed for the treatment of the visual parameters that distinguish the different types of natural stone. This paper describes the details of a computer vision system developed by AITEMIN for the automatic classification of granite pieces according to their tone, which provides an integral solution to tone grading problems in the granite processing and marketing industry. The system has been designed to be easily trained by the end user, through the learning of the samples established as tone patterns by the user. [es

  19. High-grade renal injuries are often isolated in sports-related trauma

    OpenAIRE

    Patel, Darshan P.; Redshaw, Jeffrey D.; Breyer, Benjamin N.; Smith, Thomas G.; Erickson, Bradley A.; Majercik, Sarah D.; Gaither, Thomas W.; Craig, James R.; Gardner, Scott; Presson, Angela P.; Zhang, Chong; Hotaling, James M.; Brant, William O.; Myers, Jeremy B.

    2015-01-01

    © 2015 Elsevier Ltd. All rights reserved. Introduction: Most high-grade renal injuries (American Association for Surgery of Trauma (AAST) grades III-V) result from motor vehicle collisions associated with numerous concomitant injuries. Sports-related blunt renal injury tends to have a different mechanism, a solitary blow to the flank. We hypothesized that high-grade renal injury is often isolated in sports-related renal trauma. Material and methods: We identified patients with AAST grades III...

  20. ROMI 3.1 Least-cost lumber grade mix solver using open source statistical software

    Science.gov (United States)

    Rebecca A. Buck; Urs Buehlmann; R. Edward. Thomas

    2010-01-01

    The least-cost lumber grade mix solution has been a topic of interest to both industry and academia for many years due to its potential to help wood processing operations reduce costs. A least-cost lumber grade mix solver is a rough mill decision support system that describes the lumber grade or grade mix needed to minimize raw material or total production cost (raw...

  1. Selection, development and characterisation of plasma facing materials for ITER

    International Nuclear Information System (INIS)

    Barabash, V.; Akiba, M.; Ulrickson, M.; Vieider, G.

    1996-01-01

    The current status of the selection of the armour materials for first wall, limiters and divertor are presented. The candidate armour materials are beryllium, tungsten and carbon base materials (mainly carbon fiber composites). The selection of the references grades from these material classes is discussed and the candidate grades are described. The main reasons for the selection of the reference grades are also discussed. The urgent materials R and D needs for the development of the design are described briefly. (orig.)

  2. 7 CFR 810.304 - Grades and grade requirements for canola.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for canola. 810.304... OFFICIAL UNITED STATES STANDARDS FOR GRAIN United States Standards for Canola-Terms Defined Grades and Grade Requirements § 810.304 Grades and grade requirements for canola. Grading factors Grades, U.S. Nos...

  3. Analysis of DTI-Derived Tensor Metrics in Differential Diagnosis between Low-grade and High-grade Gliomas.

    Science.gov (United States)

    Jiang, Liang; Xiao, Chao-Yong; Xu, Quan; Sun, Jun; Chen, Huiyou; Chen, Yu-Chen; Yin, Xindao

    2017-01-01

    Purpose: It is critical and difficult to accurately discriminate between high- and low-grade gliomas preoperatively. This study aimed to ascertain the role of several scalar measures in distinguishing high-grade from low-grade gliomas, especially the axial diffusivity (AD), radial diffusivity (RD), planar tensor (Cp), spherical tensor (Cs), and linear tensor (Cl) derived from diffusion tensor imaging (DTI). Materials and Methods: Fifty-three patients with pathologically confirmed brain gliomas (21 low-grade and 32 high-grade) were included. Contrast-enhanced T1-weighted images and DTI were performed in all patients. The AD, RD, Cp, Cs, and Cl values in the tumor zone, peritumoral edema zone, white matter (WM) adjacent to edema and contralateral normal-appearing white matter (NAWM) were calculated. The DTI parameters and tumor grades were statistically analyzed, and receiver operating characteristic (ROC) curve analysis was also performed. Results: The DTI metrics in the affected hemisphere showed significant differences from those in the NAWM, except for the AD values in the tumor zone and the RD values in WM adjacent to edema in the low-grade groups, as well as the Cp values in WM adjacent to edema in the high-grade groups. AD in the tumor zone as well as Cs and Cl in WM adjacent to edema revealed significant differences between the low- and high-grade gliomas. The areas under the curve (Az) of all three metrics were greater than 0.5 in distinguishing low-grade from high-grade gliomas by ROC curve analysis, and the best DTI metric was Cs in WM adjacent to edema (Az: 0.692). Conclusion: AD in the tumor zone as well as Cs and Cl in WM adjacent to edema will provide additional information to better classify gliomas and can be used as non-invasive reliable biomarkers in glioma grading.

  4. Zn graded differential calculus

    International Nuclear Information System (INIS)

    Kerner, R.

    1997-01-01

    The properties of differential algebras generated by an operator d satisfying the property d N = 0 instead of d 2 = 0 as in the usual case were investigated. The commutation relations for the generalized differentials ensuring the desired property can be put into the cyclic form a 1 a 2 a 3 ... a N = q a N a 1 a 2 ... a N-1 , where q is a primitive N-th root of unity. Examples of realizations of such differential algebras are given, either in the space of Z N -graded N x N matrix algebras, or as generalized differential calculus on manifolds. A generalization of gauge theories based on such differential calculus is briefly discussed. (author). 10 refs

  5. Uranium production from low grade Swedish shale

    International Nuclear Information System (INIS)

    Carlsson, O.

    1977-01-01

    In view of the present nuclear programmes a steep increase in uranium demand is foreseen which will pose serious problems for the uranium industry. The annual additions to uranium ore reserves must almost triple within the next 15 years in order to support the required production rates. Although there are good prospects for the discovery of further conventional deposits of uranium there is a growing interest in low grade uranium deposits. Large quantities of uranium exist in black shales, phosphates, granites, sea water and other unconventional sources. There are however factors which limit the utilization of these low grade materials. These factors include the extraction costs, the environmental constrains on mining and milling of huge amounts of ore, the development of technologies for the beneficiation of uranium and, in the case of very low grade materials, the energy balance. The availability of by-product uranium is limited by the production rate of the main product. The limitations differ very much according to types of ores, mining and milling methods and the surroundings. As an illustration a description is given of the Swedish Ranstad uranium shale project, its potential, constraints and technical solutions

  6. Vibration of Elastic Functionally Graded Thick Rings

    Directory of Open Access Journals (Sweden)

    Guang-Hui Xu

    2017-01-01

    Full Text Available The free vibration behaviors of functionally graded rings were investigated theoretically. The material graded in the thickness direction according to the power law rule and the rings were assumed to be in plane stress and plane strain states. Based on the first-order shear deformation theory and the kinetic relation of von Kárman type, the frequency equation for free vibration of functionally graded ring was derived. The derived results were verified by those in literatures which reveals that the present theory can be appropriate to predict the free vibration characteristics for quite thick rings with the radius-to-thickness ratio from 60 down to 2.09. Comparison between the plane stress case and the plane strain case indicates a slight difference. Meanwhile, the effects of the structural dimensional parameters and the material inhomogeneous parameter are examined. It is interesting that the value of the logarithmic form of vibration frequency is inversely proportional to the logarithmic form of the radius-to-thickness ratio or the mean radius.

  7. Gender discrimination in exam grading?

    DEFF Research Database (Denmark)

    Rangvid, Beatrice Schindler

    2018-01-01

    Girls, on average, obtain higher test scores in school than boys, and recent research suggests that part of this difference may be due to discrimination against boys in grading. This bias is consequential if admission to subsequent education programs is based on exam scores. This study assesses...... are scored twice (blind and non-blind). Both strategies use difference-in-differences methods. Although imprecisely estimated, the point estimates indicate a blind grading advantage for boys in essay writing of approximately 5-8% SD, corresponding to 9-15% of the gender gap in essay exam grades. The effect...... the causal effect of blind grading, exploiting two separate identification strategies. The first derives from a unique full cohort natural experiment with a grading reform, providing exogenous variation in blind grading. The other strategy derives from a field experiment where the exact same exam papers...

  8. Homogenization theory for designing graded viscoelastic sonic crystals

    International Nuclear Information System (INIS)

    Qu Zhao-Liang; Ren Chun-Yu; Pei Yong-Mao; Fang Dai-Ning

    2015-01-01

    In this paper, we propose a homogenization theory for designing graded viscoelastic sonic crystals (VSCs) which consist of periodic arrays of elastic scatterers embedded in a viscoelastic host material. We extend an elastic homogenization theory to VSC by using the elastic-viscoelastic correspondence principle and propose an analytical effective loss factor of VSC. The results of VSC and the equivalent structure calculated by using the finite element method are in good agreement. According to the relation of the effective loss factor to the filling fraction, a graded VSC plate is easily and quickly designed. Then, the graded VSC may have potential applications in the vibration absorption and noise reduction fields. (paper)

  9. Grade Retention and Unobserved Heterogeneity

    OpenAIRE

    Robert J. Gary-Bobo; Marion Gousse; Jean-Marc Robin

    2014-01-01

    We study the treatment effect of grade retention using a panel of French junior high-school students, taking unobserved heterogeneity and the endogeneity of grade repetitions into account. We specify a multistage model of human-capital accumulation with a finite number of types representing unobserved individual characteristics. Class-size and latent student-performance indices are assumed to follow finite mixtures of normal distributions. Grade retention may increase or decrea...

  10. Liquid phase sintered SiC ceramics from starting materials of different grade Cerâmicas à base de SiC sinterizadas via fase líquida a partir de matérias-primas de diferentes purezas

    Directory of Open Access Journals (Sweden)

    V. A. Izhevskyi

    2004-09-01

    Full Text Available Possibility of high performance ceramics manufactured from commercial SiC powder of technical grade has been shown. Sintering behavior and microstructure formation under conditions of liquid phase sintering (LPS with oxynitride sintering aids (AlN-Y2O3 of three SiC-based compositions have been investigated. Two of the compositions were based on Alcoa 1000 SiC powder of technical grade, and the third one, which was used as a reference, was based on H.C. Starck UF-15 fine grade commercial powder. Milling process used for Alcoa 1000 SiC powder granulometry improvement has been investigated in detail, while chemical treatment of milled SiC powders has been used for pick-up impurities removal. Dilatometric experiments showed that SiC powder of technical grade after appropriate treatment exhibits sinterability comparable with the fine grade SiC. Microstructural investigations performed on sintered samples showed that the final microstructure of the Alcoa 1000 SiC based materials was practically identical with the H.C. Starck SiC based reference ones. Preliminary investigations of hardness and fracture toughness were carried out revealing excellent results for the materials produced from cheaper, nationally produced starting powder.Neste trabalho é apresentada a possibilidade de obtenção de cerâmicas de SiC de alto desempenho a partir de matéria-prima comercial de grau técnico. Foi realizado o estudo de sinterização via fase líquida e desenvolvimento microestrutural de três composições à base de SiC tendo como aditivos de sinterização AlN e Y2O3 . Duas destas composições são à base de SiC-1000 da Alcoa, grau técnico, e a terceira, utilizada como referência, à base do UF-15 da H.C. Starck - Alemanha, pó comercial de granulometria fina. O processo de moagem do pó SiC-1000 da Alcoa foi acompanhado por medidas de distribuição granulométrica e posterior ataque químico, para remoção de impurezas. Os pós de grau técnico, ap

  11. Graded nanowire ultraviolet LEDs by polarization engineering

    Science.gov (United States)

    Carnevale, Santino D.; Kent, Thomas F.; Phillips, Patrick J.; Sarwar, A. T. M. Golam; Klie, Robert F.; Rajan, Siddharth; Myers, Roberto C.

    2012-10-01

    Given the large thermal activation energy of acceptors in high %Al AlGaN, a new approach is needed to control p-type conductivity in this material. One promising alternative to using impurity doping with thermal activation is using the intrinsic characteristics of the III-nitrides to activate dopants with polarization-induced charge in graded heterostructures. In this work polarization-induced activation of dopants is used in graded AlGaN nanowires grown by plasma-assisted molecular beam epitaxy to form ultraviolet light-emitting diodes. Electrical and optical characterization is provided, showing clear diode behavior and electroluminescent emission at 336nm. Variable temperature electrical measurements show little change in device performance at cryogenic temperatures, proving that dopant ionization is polarizationinduced rather than thermally activated.

  12. Buckling of graded coatings: A continuum model

    Science.gov (United States)

    Chiu, Tz-Cheng

    2000-12-01

    Requirements for the protection of hot section components in many high temperature applications such as earth-to-orbit winged planes and advanced turbine systems have led to the application of thermal barrier coatings (TBCs) that utilize ceramic coatings on metal substrates. An alternative concept to homogeneous ceramic coatings is the functionally graded materials (FGM) in which the composition of the coating is intentionally graded to improve the bonding strength and to reduce the magnitude of the residual and thermal stresses. A widely observed failure mode in such layered systems is known to be interface cracking that leads to spallation fracture. In most cases, the final stage of the failure process for a thin coating appears to be due to buckling instability under thermally or mechanically induced compressive stress. The objective of this study is to develop a solution to the buckling instability problem by using continuum elasticity rather than a structural mechanics approach. The emphasis in the solution will be on the investigation of the effect of material inhomogeneity in graded coatings on the instability load, the postbuckling behavior, and fracture mechanics parameters such as the stress intensity factors and strain energy release rate. In this analysis, a nonlinear continuum theory is employed to examine the interface crack problem. The analytical solution of the instability problem permits the study of the effect of material inhomogeneity upon the inception of buckling and establishes benchmark results for the numerical solutions of related problems. To study the postbuckling behavior and to calculate the stress intensity factors and strain energy release rate a geometrically nonlinear finite element procedure with enriched crack-tip element is developed. Both plane strain and axisymmetric interface crack problems in TBCs with either homogeneous or graded coating are then considered by using the finite element procedure. It is assumed that the

  13. Compositionally Graded Multilayer Ceramic Capacitors.

    Science.gov (United States)

    Song, Hyun-Cheol; Zhou, Jie E; Maurya, Deepam; Yan, Yongke; Wang, Yu U; Priya, Shashank

    2017-09-27

    Multilayer ceramic capacitors (MLCC) are widely used in consumer electronics. Here, we provide a transformative method for achieving high dielectric response and tunability over a wide temperature range through design of compositionally graded multilayer (CGML) architecture. Compositionally graded MLCCs were found to exhibit enhanced dielectric tunability (70%) along with small dielectric losses (design of miniature filters and power converters.

  14. Nonpunitive Grading Practices and Policies.

    Science.gov (United States)

    Elsner, Paul A.; Brydon, Charles W.

    Information pertaining to the overall grading standards and practices within the five Peralta Colleges is compiled and analyzed here. The report is presented in three parts. The first part deals with the historical background of traditional and non-punitive grading, the national trends toward innovation and experimentation with various forms of…

  15. Fabrication of a Ti-Al2O3 functionally graded material by dry-jet spraying of ultrafine particles and subsequent temperature-gradient sintering; Chobiryushi funsha sekisoho oyobi ondo keisha fuka shoketsuho ni yoru Ti-Al2O3 keisha kino zairyo no shisaku

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, A.; Tanizaki, H.; Iwasaki, K. [Nisshin Steel Co. Ltd., Tokyo (Japan)

    1997-04-15

    Investigations are conducted and efforts are exerted for the prevention of some problems from arising in the process of sintering of films formed by dry jet spraying of ultrafine particles. Such problems involve the exfoliation of films from the substrate, emergence of voids in the functionally graded material (FGM) when the composition of the material is altered, and initiation of cracks. A Ti-Al2O3-base stepped cylinder shape FGM is tentatively fabricated by the lamination-forming ultrafine particle dry-jet spraying method and temperature-gradient sintering method. The occurrence of defects during the sintering process may be avoided by the following steps. Addition of ultrafine hydride particles to the powder which is to be compacted into a base substrate makes the shrinkage rate of this substrate slightly higher than that of the FGM layer, and this prevents cracks due to difference in shrinkage rate. The size of pores in the FGM can be reduced if the high shrinkage rate range r=1 through r=0.5 (r=Ti/(Ti+Al2O3)) is skipped in the laminate deposition process. When the compacting pressure is appropriately chosen after lamination, cracks are prevented from occurring in parts of extraordinary shape of the substrate before it is subjected to sintering. 7 refs., 10 figs.

  16. Predictors of grade {>=}2 and grade {>=}3 radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with three-dimensional conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Jun; Li, Guang; Ma, Lianghua; Han, Chong; Zhang, Shuo; Yao, Lei [Dept. of Radiation Oncology, The First Hospital of China Medical Univ., Shenyang (China)], e-mail: gl1963516@yahoo.cn; Diao, Rao [Dept. of Experimental Technology Center, China Medical Univ., Shenyang (China); Zang, Shuang [Dept. of Nursing, China Medical Univ., Shenyang (China)

    2013-08-15

    Grade {>=}3 radiation pneumonitis (RP) is generally severe and life-threatening. Predictors of grade {>=}2 are usually used for grade {>=}3 RP prediction, but it is unclear whether these predictors are appropriate. In this study, predictors of grade {>=}2 and grade {>=}3 RP were investigated separately. The increased risk of severe RP in elderly patients compared with younger patients was also evaluated. Material and methods: A total of 176 consecutive patients with locally advanced non-small cell lung cancer were followed up prospectively after three-dimensional conformal radiotherapy. RP was graded according to Common Terminology Criteria for Adverse Events version 3.0. Results: Mean lung dose (MLD), mean heart dose, ratio of planning target volume to total lung volume (PTV/Lung), and dose-volume histogram comprehensive value of both heart and lung were associated with both grade {>=}2 and grade {>=}3 RP in univariate analysis. In multivariate logistic regression analysis, age and MLD were predictors of both grade {>=}2 RP and grade {>=}3 RP; receipt of chemotherapy predicted grade {>=}3 RP only; and sex and PTV/Lung predicted grade {>=}2 RP only. Among patients who developed high-grade RP, MLD and PTV/Lung were significantly lower in patients aged {>=}70 years than in younger patients (p<0.05 for both comparisons). Conclusions: The predictors were not completely consistent between grade {>=}2 RP and grade {>=}3 RP. Elderly patients had a higher risk of severe RP than younger patients did, possibly due to lower tolerance of radiation to the lung.

  17. Evaluation of issues around road materials for sustainable transport

    CSIR Research Space (South Africa)

    Steyn, WJVDM

    2009-07-01

    Full Text Available supplies - specifically the use of marginal materials and waste materials, effect of continuous reuse / recycling on the engineering properties of existing materials (i.e. grading, plasticity, etc) and perpetual roads cost and extraneous effects...

  18. Progressive problems higher grade physics

    CERN Document Server

    Kennedy, William

    2001-01-01

    This book fully covers all three Units studied in Scotland's Higher Grade Physics course, providing a systematic array of problems (from the simplest to the most difficult) to lead variously abled pupils to examination success.

  19. Zn3-graded colored supersymmetry

    International Nuclear Information System (INIS)

    Le Roy, B.

    1997-01-01

    Generalizations of the Grassmann algebras are built based on a few simple assumptions as follows: the algebras are graded, maximally symmetric, and contain an ordinary Grassmann algebra as a subalgebra. These algebras are graded by Z n 3 and display surprising properties that indicate their possible application to the modeling of quark fields. The generalized supersymmetry generators are built based on these algebras and their derivation operators. These generators are cubic roots of the usual supersymmetry generators. (author). 1 tab., 9 refs

  20. Synthesis of battery grade reduced silver powder

    International Nuclear Information System (INIS)

    Qadeer, R.; Hameed, M.; Ikram, S.; Munir, A.

    2002-01-01

    Process for production of battery grade reduced silver powder, an active positive material for zinc-silver oxide batteries, having specific characteristics has been optimized and the synthesized reduced silver powder was characterized. Results reveal that the values of bulk density (1.25 0.1 g/cm3) and activity (73.27 %) of synthesized reduced silver powder lies within the recommended range for use as battery material. It has purity ≥ 98% and contains Fe and Cu as traces in the concentration range of 30 5 ppm and 15 7 ppm respectively. Others determined values of surface and pores parameters are: surface area 2.6 .4 m2/g: pore volume 3.10 cm3/g: pore diameter 0.043 mu m and porosity 20%. XRD studies reveal that reduced silver powder has a cubic structure. (author)

  1. Inert gas atomization of chemical grade silicon

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, D.; Ferreira Neto, J.B.; Salgado, L.; Nogueira, P.F.; Poco, J.G.R. [Metallurgy Div. Cidade Univ., Inst. for Technological Research, Sao Paulo, SP (Brazil)

    2001-07-01

    The use of inert gas atomization to obtain chemical grade silicon particles was investigated. Both cooling rate and chemical composition are very important regarding a tailored microstructure, related with silicon performance during the synthesis of the silanos, an intermediary raw material in the silicone production. Previously refined silicon was used as raw material. Silicon with different aluminum contents were atomized and analyzed. The atomization temperature was set around 1520 C, and it was used a confined atomization nozzle. It was necessary to use a long atomization chamber to allow the cooling of the coarse silicon particles. After atomization, the powder was characterized and classified. The coarse fraction was milled. Two different particle size groups (different cooling rates) and the as atomized particles were investigated. The chemical behavior during the synthesis of the silanos was analyzed in a laboratory reactor. The relationship between cooling rate, aluminum content and silicon performance during the silanos synthesis is discussed. (orig.)

  2. Large renal angiomyolipomas: digital subtraction angiographic grading and presentation with bleeding

    International Nuclear Information System (INIS)

    Rimon, U.; Duvdevani, M.; Garniek, A.; Golan, G.; Bensaid, P.; Ramon, J.; Morag, B.

    2006-01-01

    AIM: To investigate whether a grading system of renal AMLs based on digital subtraction angiography (DSA) and computerized tomography (CT), could help to select patients for embolization. MATERIALS AND METHODS: Thirty patients with 35 renal angiomyolipomas (size range 4-20cm, mean 9.9cm) underwent both digital subtraction angiography (DSA) and computed tomography (CT). Based on the DSA appearance the tumours were graded into three grades: grade I, minimal vascularity; grade II, moderate vascularity; grade III, marked vascularity. RESULTS: There were seven grade I (mean 9.3cm, range 4.5-20cm), 18 grade II (mean 8.9cm, range 5-18cm) and 10 grade III tumours (mean 12.1cm, range 4-20cm). Five grade I tumours did not cause symptoms (71%) and two caused flank pain and haematuria, respectively (14.3% each). Nine of the grade II tumours were asymptomatic (50%), seven caused bleeding (39%) and two caused flank pain (11%). Four grade III tumours were asymptomatic (40%), five caused bleeding (50%) and one pain (10%). CONCLUSIONS: According to our criteria, large angiomyolipomas with minimal vascularity are less likely to bleed, and do not need prophylactic treatment. This needs to be confirmed in larger studies

  3. Developing test materials for dyscalculia

    DEFF Research Database (Denmark)

    Lindenskov, Lena; Bent, Lindhardt,

    Aims, requirements and context for the development of test materials for dyscalculia are analyzed. The test materials are to be used for Grade 4 pupils in Danish primary schools. Preliminary results are presented from focus group interview with adolescents and adults, who see themselves as being...

  4. 7 CFR 810.2204 - Grades and grade requirements for wheat.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for wheat. 810.2204... OFFICIAL UNITED STATES STANDARDS FOR GRAIN United States Standards for Wheat Principles Governing the Application of Standards § 810.2204 Grades and grade requirements for wheat. (a) Grades and grade requirements...

  5. 7 CFR 810.1604 - Grades and grade requirements for soybeans.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for soybeans. 810.1604... OFFICIAL UNITED STATES STANDARDS FOR GRAIN United States Standards for Soybeans Principles Governing the Application of Standards § 810.1604 Grades and grade requirements for soybeans. Grading factors Grades U.S...

  6. Materials for Fusion Applications

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří

    2013-01-01

    Roč. 53, č. 2 (2013), s. 197-212 ISSN 1210-2709. [Symposium on Plasma Physics and Technology/25./. Praha, 18.06.2012-21.06.2012] R&D Projects: GA ČR(CZ) GAP108/12/1872; GA MŠk 7G10072 Institutional research plan: CEZ:AV0Z20430508 Keywords : nuclear fusion * materials * plasma facing components * plasma-material interaction * functionally graded materials Subject RIV: BL - Plasma and Gas Discharge Physics http://ctn.cvut.cz/ap/download.php?id=797

  7. Dokuzuncu Sınıf Tarih Ders Kitabında Yer Alan Görseller Hakkında Öğretmen Görüşleri: Trabzon Örneği Perceptions of History Teachers about Visual Materials of Ninth Grade History Textbook

    Directory of Open Access Journals (Sweden)

    Ebru DEMİRCİOĞLU

    2013-09-01

    Full Text Available Textbooks are important tools of teaching and learning process ineducation system. There are some important criteria in preparingtextbooks. Especially visual materials which should be paid attention inthe preparation process of textbooks are important. Visual materials ofa qualified textbook should also have the following criteria which are asfollows: harmony between text and visual materials, clarity andcatching attention of students.The purpose of this thesis is to determine perceptions of historyteachers about visual materials of ninth grade history textbooks. Theresearch carried out experienced history teachers who teach history inthe city center of Trabzon and on the coast of the province of Trabzon.The purposive sampling was used in the research to choose historyteachers. A qualitative approach was used in the study and two datacollection tools which are an open-ended questionnaire and a semistructuredinterview to gather data. 49 history teachers participatedopen-ended questionnaire and semi-structured interviews carried outwith 8 teachers. In the light of the data, it seems that the great majorityof history teachers do not know how to use visual materials in historytextbooks and think that visual materials in the ninth grade historytextbooks do not explain texts properly. Furthermore, they also statedthat some visual materials in the ninth grade history textbook are notclear and understandable. Ders kitapları eğitim ve öğretim sürecinin en önemli unsurları arsında yer almaktadır. Bu materyallerin hazırlanmasında pek çok husus dikkate alınmalıdır. Ders kitabı hazırlama sürecinde dikkat edilmesi gereken hususların başında görseller gelmektedir. Nitelikli bir ders kitabında görseller metinle uyumlu olmanın yanında, açık, anlaşılır ve öğrencilerin ilgisini çekecek şekilde yapılandırılmalıdır.Bu çalışmanın amacı, Trabzon ilinde bulunan tarih öğretmenlerinin, dokuzuncu sınıf Tarih ders kitab

  8. Numerical simulation of thermal fracture in functionally graded ...

    Indian Academy of Sciences (India)

    Sahil Garg

    Abstract. In the present work, element-free Galerkin method (EFGM) has been extended and implemented to simulate thermal fracture in functionally graded materials. The thermo-elastic fracture problem is decoupled into two separate parts. Initially, the temperature distribution over the domain is obtained by solving the ...

  9. The Scrap Map: An Environmental Publication for Grades K-6.

    Science.gov (United States)

    Institute of Scrap Recycling Industries, Inc., Washington, DC.

    This document contains materials for a 10-day teaching unit on solid waste recycling for grades K-6. Included are: (1) "The Scrap Map," which shows recycling cycles for metals and paper, and a cryptic word puzzle; (2) three pamphlets on recycling paper, nonferrous scrap metals, and scrap iron and steel; (3) a list of the chapters of the Institute…

  10. Resource Unit on Egypt for the Intermediate Grades.

    Science.gov (United States)

    Husbands, Kenneth; Taylor, Bob

    Resources for teaching about modern and ancient Egypt are provided in this guide for intermediate grade social studies teachers. Material includes: a detailed outline for a unit on Egypt which contains a geographic overview followed by sections on the Nile River Valley, agriculture, the pharaohs, religion, architecture, science, hieroglyphics,…

  11. Catalogue of Videorecordings and Films, Kindergarten to Grade 6, 1993.

    Science.gov (United States)

    Manitoba Dept. of Education, Winnipeg. Instructional Resources Branch.

    This catalogue lists and indexes 2,233 videorecordings, 16mm film, and videodisc titles held by the Library, Manitoba Education and Training for borrowing; some are also available for dubbing. The catalog indexes materials intended for children in kindergarten through grade 6, and is divided into three parts: an annotated title and series index, a…

  12. Nonlinear properties of a graded-index photonic heterostructure

    Indian Academy of Sciences (India)

    index nonlinear materials are demonstrated theoretically. The influence of the gradation profile of the graded-index nonlinear layers on the linear and nonlinear responses of the structure are analysed. It is shown that the Q-factor of the defect mode and the threshold input intensity to achieve the optical bistability in the used ...

  13. Numerical simulation of thermal fracture in functionally graded ...

    Indian Academy of Sciences (India)

    In the present work, element-free Galerkin method (EFGM) has been extended and implemented to simulate thermal fracture in functionally graded materials. The thermo-elastic fracture problem is decoupled into two separate parts. Initially, the temperature distribution over the domain is obtained by solving the heat transfer ...

  14. Nonlinear properties of a graded-index photonic heterostructure

    Indian Academy of Sciences (India)

    The optical properties of a one-dimensional (1D) photonic heterostructure with gradedindex nonlinear materials are demonstrated theoretically. The influence of the gradation profile of the graded-index nonlinear layers on the linear and nonlinear responses of the structure are analysed. It is shown that the -factor of the ...

  15. Cur Wild Neighbors: Teaching Unit (Grades 1-3).

    Science.gov (United States)

    Sammut-Tovar, Dorothy

    Designed to sensitize primary grade students to the responsibilities of protecting wild animals, this teaching unit contains a variety of interdisciplinary worksheets and activities. Although focusing on wild animals indigenous to San Mateo County (California), materials are easily adaptable for use in other areas. Examples of activities are…

  16. Risk factors, ulcer grade and management outcome of diabetic foot ...

    African Journals Online (AJOL)

    Background: The objective was to determine the risk factors, ulcer grade, and management outcome of patients with diabetic foot ulcers (DFU) managed in a tropical tertiary hospital. Materials and Methods: This is a prospective observational study of all consecutive diabetes mellitus (DM) patients with DFU admitted in the ...

  17. 30 CFR 816.105 - Backfilling and grading: Thick overburden.

    Science.gov (United States)

    2010-07-01

    ... to restore the disturbed area to its approximate original contour. More than sufficient spoil and other waste materials occur where the overburden thickness times the swell factor exceeds the combined thickness of the overburden and coal bed prior to removing the coal, so that after backfilling and grading...

  18. Waste-to-Energy Laboratory. Grades 8-12.

    Science.gov (United States)

    HAZWRAP, The Hazardous Waste Remedial Actions Program.

    This brochure contains an activity for grades 8-12 students that focuses on the reuse of waste as an energy source by burning and converting it into energy. For this experiment students construct a calorimeter from simple recyclable material. The calorimeter is used to measure the amount of energy stored in paper and yard waste that could be used…

  19. Mathematics Program for Grade 1, De Soto Parish Curriculum Guide.

    Science.gov (United States)

    Elam, Helen; And Others

    A program of mathematics instruction for grade one is provided in this curriculum guide. The teaching goal of each lesson is stated in the Purpose section. Visual aids and manipulative materials useful in developing each lesson are suggested and additional teaching aids are listed. Suggestions for teaching the lessons are separated into three…

  20. A Computer Vision System for Automated Grading of Rough Hardwood Lumber Using a Knowledge-Based Approach

    Science.gov (United States)

    Tai-Hoon Cho; Richard W. Conners; Philip A. Araman

    1990-01-01

    A sawmill cuts logs into lumber and sells this lumber to secondary remanufacturers. The price a sawmiller can charge for a volume of lumber depends on its grade. For a number of species the price of a given volume of material can double in going from one grade to the next higher grade. Thus, accurately establishing the grade of a volume of hardwood lumber is very...

  1. Functionally Graded Materials using Plasma Spray with Nano Structured Ceramic

    International Nuclear Information System (INIS)

    Sioh, E L; Tok, A I Y

    2013-01-01

    In this paper, nano structured FGM was fabricated using DC plasma spray technique. Nano structured and micro structured powder were used as the feeding powder with steel substrate. The spray parameters was optimized and characterisation of nano-ceramic FGM and micro-ceramic FGM were done using bending test and micro-hardness test. Experimental results have shown that the nano-structured FGM exhibit 20% improvement flexure strength and 10% in hardness. A comparison was made between sintered micro ceramic tile and nano ceramic FGM using simple drop test method.

  2. Understanding Thermal Transport in Graded, Layered and Hybrid Materials

    Science.gov (United States)

    2014-04-01

    infrared pyrometer aimed at the sample surface. In year 2 of the effort, TEM grids were acquired from Ted Pella, which consist of perforated membrane of...calibrated infrared pyrometer aimed at the sample surface. The sputter-coated diamond substrates were characterized with electron probe microanalysis...through a pulse compressor and then through an electro- optic modulator (EOM), which imposes a square-wave pulse train with a frequency of 9.8 MHz

  3. Composites of Upgraded Metallurgical Grade (UMG) Si with Photovoltaic (PV) Grade Si

    Energy Technology Data Exchange (ETDEWEB)

    Hovel, Harold; Prettyman, Kevin; Krause, Rainer; Dipankar, Roy

    2015-03-27

    At the beginning of this project 125 wafers of UMG material blended with non-UMG were obtained in the various blends; 50/50,70/30,80/20. 90/10 and 100% UMG. Solar grade , non-UMG material was used for comparison. Many techniques for starting substrate evaluation were used including lifetime, resitivity, SEM, IPCMS. Some degree of gettering was implemented by lengthening the time of phosphorous diffusion. The UMG/solar blends resulted in 14.5% -15% efficiencies, and even 100% UMG showed 14.5% values, not less than standard cells manufactured at the time and an encouraging result for the prospects of using UMG material due to the lower $/watt. A later decline in the cost of Si and an emphasis on reaching higher efficiencies in general led to a vanishing interest in the use of UMG.

  4. Physical Characteristics. Resource Unit III, Grade 6. Providence Social Studies Curriculum Project.

    Science.gov (United States)

    Providence Public Schools, RI.

    GRADES OR AGES: Grade 6. SUBJECT MATTER: Social studies; physical geography of Latin America and Africa. ORGANIZATION AND PHYSICAL APPEARANCE: The major portion of the guide, which develops the unit, is laid out in three columns, one each for topics, activities, and materials. Other sections are in list form. The guide is mimeographed and…

  5. Eighth Grade Social Studies. An Experimental Program in Geography and Anthropology.

    Science.gov (United States)

    Hanson, James; And Others

    GRADES OR AGES: Grade 8. SUBJECT MATTER: Geography and Anthropology. ORGANIZATION AND PHYSICAL APPEARANCE: The introductory material includes descriptions of geography and anthropology as disciplines, the basic course objectives, techniques for evaluating objectives and a student self-evaluation form. The guide covers six units: 1) "What Kind of…

  6. On-Demand Grades: The Effect of Online Grade Book Access on Student Mastery and Performance Goal Orientations, Grade Orientation, Academic Self Efficacy, and Grades

    Science.gov (United States)

    Seldow, Adam Lowell

    2010-01-01

    With the widespread growth of broadband Internet access, teachers, and in many cases, schools and school districts are transitioning from traditional paper-based grade books to student accessible online (Web-based) grade books. Online grade books offer students 24/7, on demand access to grades and various other student data, and have the potential…

  7. Pharmacokinetic MRI of the prostate. Parameters for differentiating low-grade and high-grade prostate cancer

    International Nuclear Information System (INIS)

    Franiel, T.; Taupitz, M.; Asbach, P.; Beyersdorff, D.; Luedemann, L.; Rost, J.

    2009-01-01

    Purpose: to investigate whether pharmacokinetic MRI parameters ''perfusion, blood volume, mean transit time (MTT), interstitial volume, permeability, extraction coefficient, delay, and dispersion'' allow the differentiation of low-grade (Gleason score ≤ 6) and high-grade (Gleason score ≥ 7) prostate cancer. Materials and method: forty-two patients with prostate cancer verified by biopsy (PSA 2.7 to 31.4ng/ml) and scheduled for prostatectomy underwent MRI at 1.5 Tesla using the dynamic contrast-enhanced inversion-prepared dual-contrast gradient echo sequence (temporal resolution, 1.65 s) and a combined endorectal body phased array coil. Parametric maps were computed using a sequential 3-compartment model and the corresponding post-processing algorithms. A total of 41 areas of prostate cancer (15 low-grade, 26 high-grade cancers) in 32 patients were able to be correlated with the prostatectomy specimens and were included in the analysis. Results: low-grade prostate cancers had a higher mean blood volume (1.76% vs. 1.64%, p = 0.039), longer MTT (6.39 s vs. 3.25 s, p -1 vs. 3.86 min -1 , p = 0.011) than high-grade cancers. No statistically significant difference was found for perfusion (p = 0.069), interstitial volume (p = 0.849), extraction coefficient (p = 0.615), delay (p = 0.489), and dispersion (p = 0.306). (orig.)

  8. On the union of graded prime ideals

    Directory of Open Access Journals (Sweden)

    Uregen Rabia Nagehan

    2016-01-01

    Full Text Available In this paper we investigate graded compactly packed rings, which is defined as; if any graded ideal I of R is contained in the union of a family of graded prime ideals of R, then I is actually contained in one of the graded prime ideals of the family. We give some characterizations of graded compactly packed rings. Further, we examine this property on h – Spec(R. We also define a generalization of graded compactly packed rings, the graded coprimely packed rings. We show that R is a graded compactly packed ring if and only if R is a graded coprimely packed ring whenever R be a graded integral domain and h – dim R = 1.

  9. Architected Cellular Materials

    Science.gov (United States)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  10. Strategies for denaturing the weapons-grade plutonium stockpile

    International Nuclear Information System (INIS)

    Buckner, M.R.; Parks, P.B.

    1992-10-01

    In the next few years, approximately 50 metric tons of weapons-grade plutonium and 150 metric tons of highly-enriched uranium (HEU) may be removed from nuclear weapons in the US and declared excess. These materials represent a significant energy resource that could substantially contribute to our national energy requirements. HEU can be used as fuel in naval reactors, or diluted with depleted uranium for use as fuel in commercial reactors. This paper proposes to use the weapons-grade plutonium as fuel in light water reactors. The first such reactor would demonstrate the dual objectives of producing electrical power and denaturing the plutonium to prevent use in nuclear weapons

  11. The limiting efficiency of band gap graded solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rafat, Nadia H. [Faculty of Engineering, Cairo University, Giza (Egypt); Habib, S.E.D. [Faculty of electronics and communication, Cairo University, Giza (Egypt)

    1998-09-04

    Two fundamental mechanisms limit the maximum attainable efficiency of solar cells, namely the radiative recombination and Auger recombination. We show in this paper that proper band gap grading of the solar cell localizes the Auger recombination around the metallurgical junction. Two beneficial effects result from this Auger recombination localization; first the cell is less sensitive to the surface conditions, and second, the previous estimates for the limiting efficiency of solar cells by Shockley, Tiedje, and Green are revised upwardly. We calculate the optimum bandgap grading profile for several real material systems, including GaInAsP lattice matched to InP, and a-SiGe on a-Si substrate

  12. EDF specifications on nuclear grade resins

    International Nuclear Information System (INIS)

    Mascarenhas, Darren; Gressier, Frederic; Taunier, Stephane; Le-Calvar, Marc; Ranchoux, Gilles; Marteau, Herve; Labed, Veronique

    2012-09-01

    Ion exchange resins are widely used across EDF, especially within the nuclear division for the purification of water. Important applications include primary circuit, secondary circuit and effluent treatment, which require high quality nuclear grade resins to retain the dissolved species, some of which may be radioactive. There is a need for more and more efficient purification in order to decrease worker dose during maintenance but also to decrease volumes of radioactive resin waste. Resin performance is subject to several forms of degradation, including physical, chemical, thermal and radioactive, therefore appropriate resin properties have to be selected to reduce such effects. Work has been done with research institutes, manufacturers and on EDF sites to select these properties, create specifications and to continuously improve on these specifications. An interesting example of research regarding resin performance is the resin degradation under irradiation. Resins used in the CVCS circuit of EDF nuclear power plants are subject to irradiation over their lifetime. A study was carried out on the effects of total integrated doses of 0.1, 1 and 10 MGy on typically used EDF mixed bed resins in a 'mini-CVCS' apparatus to simultaneously test actual primary circuit fluid. The tests confirmed that the resins still perform efficiently after a typical CVCS radiation dose. Certain resins also need additional specifications in order to maintain the integrity of the particular circuits they are used in. Recently, EDF has updated its requirements on these high purity nuclear grade resins, produced generic doctrines for all products and materials used on site which include resins of all grades, and as a result have also updated a guide on recommended resin usage for the French fleet of reactors. An overview of the evolutions will be presented. (authors)

  13. 7 CFR 810.404 - Grades and grade requirements for corn.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for corn. 810.404... OFFICIAL UNITED STATES STANDARDS FOR GRAIN United States Standards for Corn Principles Governing the Application of Standards § 810.404 Grades and grade requirements for corn. Grade Minimum test weight per...

  14. 7 CFR 810.1804 - Grades and grade requirements for sunflower seed.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for sunflower seed. 810... AGRICULTURE OFFICIAL UNITED STATES STANDARDS FOR GRAIN United States Standards for Sunflower Seed Principles Governing the Application of Standards § 810.1804 Grades and grade requirements for sunflower seed. Grade...

  15. Instructional and Grading Practices That Change Grading Fidelity: An Action Research Study

    Science.gov (United States)

    Smith, Michael A.

    2014-01-01

    Historically, final course grades of sixth- through eighth-grade language arts, mathematics, and eighth grade science students at the primary research site, Site A (pseudonym), suggest a high degree of grade inflation or disassociation when grade point averages (GPA) were compared to actual student performance levels as measured by annual state…

  16. SCIENCE, KINDERGARTEN AND GRADE ONE.

    Science.gov (United States)

    Fresno County Schools, CA.

    A GUIDE FOR THE TEACHING OF SCIENCE IN KINDERGARTEN AND FIRST GRADE IS PRESENTED. THE PURPOSE IS TO HELP TEACHERS IN IMPLEMENTING THE COURSE REQUIREMENTS IN SCIENCE. THE MAJOR GOAL IS TEACHING CHILDREN TO THINK IN A SCIENTIFIC WAY. SUGGESTED UNITS FOR KINDERGARTEN ARE ANIMALS AND PLANTS, WEATHER, DISCOVERY, AND THE FIVE SENSES. THE UNITS FOR GRADE…

  17. The Reliability of College Grades

    Science.gov (United States)

    Beatty, Adam S.; Walmsley, Philip T.; Sackett, Paul R.; Kuncel, Nathan R.; Koch, Amanda J.

    2015-01-01

    Little is known about the reliability of college grades relative to how prominently they are used in educational research, and the results to date tend to be based on small sample studies or are decades old. This study uses two large databases (N > 800,000) from over 200 educational institutions spanning 13 years and finds that both first-year…

  18. Social Studies Curriculum: Grade Six.

    Science.gov (United States)

    Pease, Arthur

    This document outlines the content of the grade 6 social studies curriculum of the Lebanon School District, Lebanon, New Hampshire. The program is essentially a chronological review of western civilization, which includes pre-historic man, early civilization, classical civilizations of Greece and Rome, Medieval period, and the Age of Expansion.…

  19. Science Equity in Third Grade

    Science.gov (United States)

    Kohlhaas, Kay; Lin, Hsin-Hui; Chu, Kwang-Lee

    2010-01-01

    The earliest national accountability tests occur at the fourth-grade level and the outcomes are aggregated. This national study exposes the depth of science education inequities a full year earlier by disaggregating third graders' demographic data with the science performance. A full 3-way ANOVA model was applied to test the 3 main effects…

  20. Seals. Grades 3-6.

    Science.gov (United States)

    New England Aquarium, Boston, MA.

    Explanations of a marine mammal rescue program and information on seals and sea lions are presented in this curriculum package for intermediate grade teachers. Activities are highlighted which focus on the natural history of harbor seals. This unit contains: (1) pre-trip activities (including fact sheets and worksheets on the different types of…

  1. Dictionary materials engineering, materials testing

    International Nuclear Information System (INIS)

    1994-01-01

    This dictionary contains about 9,500 entries in each part of the following fields: 1) Materials using and selection; 2) Mechanical engineering materials -Metallic materials - Non-metallic inorganic materials - Plastics - Composites -Materials damage and protection; 3) Electrical and electronics materials -Conductor materials - Semiconductors - magnetic materials - Dielectric materials - non-conducting materials; 4) Materials testing - Mechanical methods - Analytical methods - Structure investigation - Complex methods - Measurement of physical properties - Non-destructive testing. (orig.) [de

  2. Energy Education Materials Inventory

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    The two volumes of the Energy Education Materials Inventory (EEMI) comprise an annotated bibliography of widely available energy education materials and reference sources. This systematic listing is designed to provide a source book which will facilitate access to these educational resources and hasten the inclusion of energy-focused learning experiences in kindergarten through grade twelve. EEMI Volume II expands Volume I and contains items that have become available since its completion in May, 1976. The inventory consists of three major parts. A core section entitled Media contains titles and descriptive information on educational materials, categorized according to medium. The other two major sections - Grade Level and Subject - are cross indexes of the items for which citations appear in the Media Section. These contain titles categorized according to grade level and subject and show the page numbers of the full citations. The general subject area covered includes the following: alternative energy sources (wood, fuel from organic wastes, geothermal energy, nuclear power, solar energy, tidal power, wind energy); energy conservation, consumption, and utilization; energy policy and legislation, environmental/social aspects of energy technology; and fossil fuels (coal, natural gas, petroleum). (RWR)

  3. Identification of ballast grading for rail track

    Directory of Open Access Journals (Sweden)

    Yifei Sun

    2017-10-01

    Full Text Available Grading has long been recognised to critically influence the mechanical behaviour of ballast. To identify the ballast grading for heavy-haul rail track, monotonic and cyclic triaxial tests are conducted to assess the performances of different gradings. Permanent deformations, aggregates degradation, resilience, shear resistance, maximum and minimum densities are recorded and analysed. The grading is found to affect the behaviour of ballast in that coarser gradings exhibit relatively better strength, resilience and therefore less permanent deformation. However, ballast degradation increases with the overall aggregate size. Therefore, to identify the grading for ballast with different performance objectives, a grey relational theory is used to convert the multi-objective into single-objective, i.e. grey relational grade. A relatively optimal grading that provides the highest grey relational grade is thus suggested for the improved ballast performance.

  4. Ability Of Mathematical Reasoning in SMK 10th Grade with LAPS- Heuristic using Performance Assessment

    Directory of Open Access Journals (Sweden)

    Aulia Nur Arivina

    2017-11-01

    Full Text Available The purposes of this research are: (1 Test the learning with LAPS-Heuristic model using performance assessment on 10th grade of Trigonometry material is complete, (2 to test the difference of students' mathematical reasoning ability on 10th grade of Trigonometry material between the learning model of LAPS-Heuristic using performance assessment, LAPS-Heuristic learning model with Expository learning model, (3 test the ability of mathematical reasoning with learning model of LAPS-Heuristik on Trigonometry material of SMK on 10th grade using performance assessment is increase. This is a quantitative research. The population is students of 10th grade of SMK 10 Semarang academic year 2016/2017 and the subject of research is selected by clustering random sampling. The results show that (1 Learning by model LAPS-Heuristic using performance assessment on 10th grade of Trigonometry material is complete (2 there are differences in students' mathematical reasoning ability on 10th grade of Trigonometry materials between LAPS-Heuristic learning model using performance assessment, LAPS-Heuristic learning model, and Expository learning model, (3 The ability of mathematical reasoning with learning model of LAPS-Heuristic on Trigonometry material of SMK class X using performance assessment increased.

  5. Maximization of the Thermoelectric Cooling of a Graded Peltier Device by Analytical Heat-Equation Resolution

    Science.gov (United States)

    Thiébaut, E.; Goupil, C.; Pesty, F.; D'Angelo, Y.; Guegan, G.; Lecoeur, P.

    2017-12-01

    Increasing the maximum cooling effect of a Peltier cooler can be achieved through material and device design. The use of inhomogeneous, functionally graded materials may be adopted in order to increase maximum cooling without improvement of the Z T (figure of merit); however, these systems are usually based on the assumption that the local optimization of the Z T is the suitable criterion to increase thermoelectric performance. We solve the heat equation in a graded material and perform both analytical and numerical analysis of a graded Peltier cooler. We find a local criterion that we use to assess the possible improvement of graded materials for thermoelectric cooling. A fair improvement of the cooling effect (up to 36%) is predicted for semiconductor materials, and the best graded system for cooling is described. The influence of the equation of state of the electronic gas of the material is discussed, and the difference in term of entropy production between the graded and the classical system is also described.

  6. 7 CFR 51.2123 - Foreign material.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Foreign material. 51.2123 Section 51.2123 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Almonds Definitions § 51.2123 Foreign material. Foreign material means...

  7. 7 CFR 51.2738 - Foreign material.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Foreign material. 51.2738 Section 51.2738 Agriculture... Standards for Grades of Shelled Spanish Type Peanuts Definitions § 51.2738 Foreign material. Foreign material means pieces or loose particles of any substance other than peanut kernels or skins. ...

  8. DUGDALE-MAUGIS ADHESIVE NORMAL CONTACT OF AXISYMMETRIC POWER-LAW GRADED ELASTIC BODIES

    Directory of Open Access Journals (Sweden)

    Emanuel Willert

    2018-02-01

    Full Text Available A closed-form general analytic solution is presented for the adhesive normal contact of convex axisymmetric power-law graded elastic bodies using a Dugdale-Maugis model for the adhesive stress. The case of spherical contacting bodies is studied in detail. The known JKR- and DMT-limits can be derived from the general solution, whereas the transition between both can be captured introducing a generalized Tabor parameter depending on the material grading. The influence of the Tabor parameter and the material grading is studied.

  9. Vascular endothelial growth factor expression and angiogenesis in various grades and subtypes of meningioma

    Directory of Open Access Journals (Sweden)

    Priya Dharmalingam

    2013-01-01

    Full Text Available Background: Vascular endothelial growth factor (VEGF expression has been extensively studied in astrocytoma, whereas relatively less literature exists on VEGF expression in meningioma. Materials and Methods: Patients operated for meningioma from 2006 to 2011 (n = 46 were included. Tumor was subtyped and graded as per WHO grading. Immunohistochemistry was performed for MIB labeling index, VEGF, and CD 34 staining. The patterns of VEGF expression in various histological subtypes and grades and its correlation with microvascular density were analyzed. Results: This series consisted of 40 Grade I meningioma, 4 Grade II tumors, and 2 Grade III tumors. While 14 (30.4% tumors showed no staining with VEGF antibody, 32 (69.6% were positive for VEGF. Sixty five percent of Grade I tumors showed VEGF positivity, while 100% of Grade II and Grade III tumors were VEGF positive (P = 0.157. The mean microvascular density in VEGF-negative tumors was 9.00, while that of VEGF-positive tumors was 17.81(P = 0.013. There was a gradual increase in microvascular density from tumors which are negative for VEGF to tumors which expressed moderate to strong VEGF, the difference being statistically significant (P = 0.009. Conclusions: VEGF expression correlated with the microvascular density in meningioma irrespective of tumor grade, with a gradual increase in microvascular density in relation to the VEGF score.

  10. [Classification study on commodity specification and grade standard of Pseudostellariae Radix].

    Science.gov (United States)

    Kang, Chuan-Zhi; Zhou, Tao; Guo, Lan-Ping; Han, Bang-Xing; Huang, Lu-Qi; Xiao, Cheng-Hong; Xiong, Hou-Xi; Chen, Xue-Mei

    2014-08-01

    To study the commodity specification and grade standard of Pseudostellaria Radix, for standardizing market order and achieving industrialization, standardization and modernization of Pseudostellariae Radix. The different areas and grade medicinal materials of Pseudostellariae Radix were respectively measured in quantitative characteristics of appearance, and the present grade classification of Pseudostellaria Radix was scientifically verified by the content of polysaccharide. Then the determination data were evaluated by spss correlation analysis, principal component analysis and cluster analysis. So combining with the actual production, the commodity grade standard of Pseudostellariae Radix was formulated. Correlation analysis indicated that the present grade classification of Pseudostellaria Radix was reasonable, and the more the grade of Pseudostellariae Radix was high, the more the content of polysaccharide was high. Meanwhile, length as a classification index was not suitable for the commodity grade standard of Pseudostellariae Radix. Using principal component analysis and cluster analysis, combining actual production, the thickest diameter, weight of single root tuber and the number of 50 g root tuber were filtrated and the grade was divided into 5 ranks: big, mid- dle, small selected goods, big ungraded goods and small ungraded goods. the commodity specification and grade standard of Pseudostellariae Radix that mainly included the thickest diameter, weight of single root tuber and the number of 50 g root tuber was formulated, the standard was divided into 5 grade. Each grade was not only consistent with the present situation of medicinal materials market, it could also reflected the intrinsic quality of Pseudostellariae Radix. In conclusion, the standard could be used as a classifica- tion basis to the commodity specification and grade.

  11. Sputtering effects on mirrors made of different tungsten grades

    Science.gov (United States)

    Voitsenya, V. S.; Ogorodnikova, O. V.; Bardamid, A. F.; Bondarenko, V. N.; Konovalov, V. G.; Lytvyn, P. M.; Marot, L.; Ryzhkov, I. V.; Shtan', A. F.; Skoryk, O. O.; Solodovchenko, S. I.

    2018-03-01

    Because tungsten (W) is used in present fusion devices and it is a reference material for ITER divertor and possible plasma-facing material for DEMO, we strive to understand the response of different W grades to ion bombardment. In this study, we investigated the behavior of mirrors made of four polycrystalline W grades under long-term ion sputtering. Argon (Ar) and deuterium (D) ions extracted from a plasma were used to investigate the effect of projectile mass on surface modification. Depending on the ion fluence, the reflectance measured at normal incidence was very different for different W grades. The lowest degradation rate of the reflectance was measured for the mirror made of recrystallized W. The highest degradation rate was found for one of the ITER-grade W samples. Pre-irradiation of a mirror with 20-MeV W6+ ions, as simulation of neutron irradiation in ITER, had no noticeable influence on reflectance degradation under sputtering with either Ar or D ions.

  12. Sliding Contact Fatigue of Graded Zirconia with External Esthetic Glass

    Science.gov (United States)

    Ren, L.; Janal, M.N.; Zhang, Y.

    2011-01-01

    Veneer chipping and fracture are common failure modes for porcelain-veneered zirconia dental restorations. We hypothesized that the graded glass/zirconia/glass with external esthetic glass (e-GZG) can increase the lifetime and improve resistance to veneer chipping and fracture relative to porcelain-veneered zirconia, while providing necessary esthetics. Previously, we have demonstrated that a graded glass-zirconia surface possesses excellent resistance to occlusal-like sliding contact fatigue. Here, we investigated the sliding contact fatigue response of this graded glass-zirconia surface with external esthetic glass. This external glass is essential for shade options, for preventing excessive wear of opposing dentition, and for protecting Y-TZP from hydrothermal degradation. e-GZG plates were bonded to composite blocks and subjected to prolonged sliding contact up to 10 million cycles at 200 N in water. The resistance to sliding contact fatigue of e-GZG matches that of monolithic Y-TZP, and both of these materials demonstrated lifetimes that were orders of magnitude longer than that of porcelain-veneered zirconia. Graded e-GZG is a promising restorative material. PMID:21666105

  13. Grading of quality assurance requirements

    International Nuclear Information System (INIS)

    1991-01-01

    The present Manual provides guidance and illustrative examples for applying a method by which graded quality assurance requirements may be determined and adapted to the items and services of a nuclear power plant in conformance with the requirements of the IAEA Nuclear Safety Standards (NUSS) Code and Safety Guides on quality assurance. The Manual replaces the previous publication IAEA-TECDOC-303 on the same subject. Various methods of grading quality assurance are available in a number of Member States. During the development of the present Manual it was not considered practical to attempt to resolve the differences between those methods and it was preferred to identify and benefit from the good practices available in all the methods. The method presented in this Manual deals with the aspects of management, documentation, control, verification and administration which affect quality. 1 fig., 4 tabs

  14. A Grade IV Isthmic Spondylolisthesis.

    Science.gov (United States)

    Kolber, Morey J; Hanney, William J

    2017-12-01

    A 15-year-old adolescent boy was referred by an orthopaedic surgeon for treatment of right gluteal and thigh pain. Following treatment that reduced his pain, he experienced acute onset of bilateral radiculopathy. He was referred back to the physician, who ordered radiographs and magnetic resonance imaging, which identified a grade IV isthmic spondylolisthesis at the L5-S1 level. J Orthop Sports Phys Ther 2017;47(12):971. doi:10.2519/jospt.2017.7547.

  15. Grade Expectations: Rationality and Overconfidence

    Directory of Open Access Journals (Sweden)

    Jan R. Magnus

    2018-01-01

    Full Text Available Confidence and overconfidence are essential aspects of human nature, but measuring (overconfidence is not easy. Our approach is to consider students' forecasts of their exam grades. Part of a student's grade expectation is based on the student's previous academic achievements; what remains can be interpreted as (overconfidence. Our results are based on a sample of about 500 second-year undergraduate students enrolled in a statistics course in Moscow. The course contains three exams and each student produces a forecast for each of the three exams. Our models allow us to estimate overconfidence quantitatively. Using these models we find that students' expectations are not rational and that most students are overconfident, in agreement with the general literature. Less obvious is that overconfidence helps: given the same academic achievement students with larger confidence obtain higher exam grades. Female students are less overconfident than male students, their forecasts are more rational, and they are also faster learners in the sense that they adjust their expectations more rapidly.

  16. Grade Expectations: Rationality and Overconfidence

    Science.gov (United States)

    Magnus, Jan R.; Peresetsky, Anatoly A.

    2018-01-01

    Confidence and overconfidence are essential aspects of human nature, but measuring (over)confidence is not easy. Our approach is to consider students' forecasts of their exam grades. Part of a student's grade expectation is based on the student's previous academic achievements; what remains can be interpreted as (over)confidence. Our results are based on a sample of about 500 second-year undergraduate students enrolled in a statistics course in Moscow. The course contains three exams and each student produces a forecast for each of the three exams. Our models allow us to estimate overconfidence quantitatively. Using these models we find that students' expectations are not rational and that most students are overconfident, in agreement with the general literature. Less obvious is that overconfidence helps: given the same academic achievement students with larger confidence obtain higher exam grades. Female students are less overconfident than male students, their forecasts are more rational, and they are also faster learners in the sense that they adjust their expectations more rapidly. PMID:29375449

  17. Materials Frontiers to Empower Quantum Computing

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Antoinette Jane [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sarrao, John Louis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Richardson, Christopher [Laboratory for Physical Sciences, College Park, MD (United States)

    2015-06-11

    This is an exciting time at the nexus of quantum computing and materials research. The materials frontiers described in this report represent a significant advance in electronic materials and our understanding of the interactions between the local material and a manufactured quantum state. Simultaneously, directed efforts to solve materials issues related to quantum computing provide an opportunity to control and probe the fundamental arrangement of matter that will impact all electronic materials. An opportunity exists to extend our understanding of materials functionality from electronic-grade to quantum-grade by achieving a predictive understanding of noise and decoherence in qubits and their origins in materials defects and environmental coupling. Realizing this vision systematically and predictively will be transformative for quantum computing and will represent a qualitative step forward in materials prediction and control.

  18. Does the Compliance of the Bladder Affect the Grade of Vesicoureteral Reflux?

    Directory of Open Access Journals (Sweden)

    Ferhat Kilinc

    2013-10-01

    Full Text Available Aim: We retrospectively reviewed videourodynamic outcomes in children with primary vesicoureteral reflux. The aim of this study to evaluate the relationship between vesicoureteral reflux grade and bladder compliance. Material and Method: Videourodynamic traces of 53 children with primary vesicoureteral reflux investigated between January 2004 and January 2012 were reviewed. The detrusor pressures of the point when the reflux started were recorded. The detrusor pressures 10 cmH2O or less at that point was accepted as normal compliance (Group 1, the detrusor pressures more than10 cm H2O was accepted as hipocompliance (Group 2. The reflux grades were divided into two grades, low-grade reflux (grades 1 and 2, high-grade reflux (grades 3, 4 and 5. Data were analyzed using the chi-square test. Results: Patients’ ages ranged between 5 and 11 years (mean 7.09±1.81 years. Of the 53 patients, 29 (54.7% had normal compliance (Group 1, 24 (45.3% had hipocompliance (Group 2. Twenty-four (82.8% patients in-group 1 had a low-grade reflux, 5 (17.2% patients had a high-grade reflux. In group 2, 8 (33.3% patients had a low-grade reflux, 16 (66.7% patients had a high-grade reflux. The detected high-grade reflux in-group 2 was significantly higher than in-group 1 (p<0.001. Discussion: The physicians should be considering the bladder compliance at the point when the reflux started in primary vesicoureteral reflux cases. The bladder hipocompliance may play a secondary role in reflux grade.

  19. Evaluation of SCC morphology on L-grade stainless steels in BWRs

    International Nuclear Information System (INIS)

    Suzuki, Shunichi; Takamori, Kenrou; Kumagai, Katsuhiko; Ooki, Suguru; Fukuda, Toshihiko; Yamashita, Hironobu; Futami, Tsuneo

    2004-01-01

    Recently, a large number of stress corrosion cracking (SCC) have been observed in core shrouds and re-circulation (PLR) pipings made of L-grade stainless steel in Japanese BWRs (Boiling Water Reactors). L-grade stainless steels, which contain less carbon to avoid the sensitization due to welding, have been developed as SCC-resistant materials after many SCC experiences on sensitized type304. As L-grade materials, especially type 316L and 316NG stainless steels have shown little susceptibility to SCC initiation in laboratory tests, it has to be considered that there exist some unknown factors excluding sensitization that cause SCC in these materials. From the detailed investigations of plant components so far, SCC of L-grade stainless steels show different characteristics from those observed on conventional sensitized type 304 especially in their crack morphology. In this paper, classification of observed cracks according to their morphology is discussed, followed by evaluation on root causes of SCC. The present conclusions are (1) crack orientations mainly depend on the maximum principal stress direction of welding residual stresses, (2) SCC susceptibility of L-grade stainless steels is enhanced by material hardening by machining or grinding, and (3) in L-grade materials SCC can propagate into the weld metal but in many case, cracks seem to be arrested near the fusion line. (author)

  20. The grading management of the quality assurance

    International Nuclear Information System (INIS)

    Ma Xiaozheng; Han Shufang; Yu Bei; Tian Xuehang

    2009-01-01

    This paper introduces the quality assurance grading management of the items, services and technology process on nuclear power plants (nuclear island, conventional island, BOP), such as the requirements and aim in the related code, guide, technical document, the requirements for the related units, the grading principle and grading, the considering method for the differences of QA requirements of the each QA grand, as well as the status and propositions in the QA grading management in China. (authors)

  1. The pathologist's mean grade is constant and individualizes the prognostic value of bladder cancer grading.

    Science.gov (United States)

    van Rhijn, Bas W G; van Leenders, Geert J L H; Ooms, Bert C M; Kirkels, Wim J; Zlotta, Alexandre R; Boevé, Egbert R; Jöbsis, Adriaan C; van der Kwast, Theo H

    2010-06-01

    A new grading system for bladder cancer (BCa) was adopted in 2004 to reduce observer variability and provide better prognostic information. We compared the World Health Organization (WHO) 1973 and 2004 systems for observer variability and prognosis. Slides of 173 primary non-muscle-invasive BCa were reviewed two times by four pathologists. Intra- and interobserver variability were assessed using κ statistics. We determined the mean grade (eg, G1/low malignant potential is 1 grade point, G2/low grade is 2 grade points) of the pathologists per grading cycle. Kaplan-Meier analyses were applied for prediction of recurrence and progression. For WHO 2004 and 1973 grading, the agreement between the pathologists was 39-74% (κ: 0.14-0.58) and 39-64% (κ: 0.15-0.41), respectively. The intraobserver agreement varied from 71% to 88% (κ: 0.55-0.81). The mean grade of a pathologist was constant (difference below 0.1 grade point) irrespective of the grading system. Conversely, mean-grade differences among the pathologists were high, up to 0.7 grade point. The mean grades for the WHO 2004 system were 0.3-0.5 grade point higher than those of WHO 1973. Mean grade distinguished low and high graders among the pathologists and was strongly linked with risk of progression in each grade category. The variation in mean grade among individual pathologists exceeded the grade shift caused by WHO 2004 grading. Knowledge of the pathologist's mean grade allows a better assessment of the prognostic value of grading. Mean grade has the potential to become a tool for quality assurance in pathology. Copyright © 2009 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  2. Registration Patterns Under Two Different Grading Systems.

    Science.gov (United States)

    Remley, Audrey W.

    In the early 1960's, Westminster College adopted a new grading system, with the traditional grade levels of A, B, C, D, and F converted to DN (Distinction), HP (High Pass), P (Pass), and NC (No Credit). NC replaced both D and F of the old system, and grade point averages were abolished, in an effort to encourage students to register in more…

  3. Grade Inflation: An Issue for Higher Education?

    Science.gov (United States)

    Caruth, Donald L.; Caruth, Gail D.

    2013-01-01

    Grade inflation impacts university credibility, student courses of study, choices of institution, and other areas. There has been an upward shift in grades without a corresponding upward shift in knowledge gained. Some of the most frequently mentioned causes of grade inflation are: (1) student evaluations of professors; (2) student teacher…

  4. Mechanical grading of round timber beams

    Science.gov (United States)

    David W. Green; Thomas M. Gorman; James W. Evans; Joseph F. Murphy

    2006-01-01

    Current procedures used to sort round timber beams into structural grades rely on visual grading methods and property assignments based on modification of clear wood properties. This study provides the technical basis for mechanical grading of 228 mm (9 in.) diameter round timbers. Test results on 225 round Engelmann spruce–alpine fir–lodgepole pine beams demonstrate...

  5. Demystify Learning Expectations to Address Grade Inflation

    Science.gov (United States)

    Hodges, Linda C.

    2014-01-01

    This article describes the subject of "grade inflation," a reference to educators giving higher grades to student work than their expectations for student achievement warrant. Of the many reasons why this practice happens, Hodges specifically discusses inflating grades as "a natural consequence" when the faculty really…

  6. Does Education Corrupt? Theories of Grade Inflation

    Science.gov (United States)

    Oleinik, Anton

    2009-01-01

    Several theories of grade inflation are discussed in this review article. It is argued that grade inflation results from the substitution of criteria specific to the search for truth by criteria of quality control generated outside of academia. Particular mechanisms of the grade inflation that occurs when a university is transformed into a…

  7. Graded core/shell semiconductor nanorods and nanorod barcodes

    Science.gov (United States)

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2010-12-14

    Graded core/shell semiconductor nanorods and shaped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  8. Standard specification for Nuclear-Grade aluminum oxide powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification provides the chemical and physical requirements for nuclear-grade aluminum oxide powder intended for fabrication into shapes for nuclear applications. Two specific uses for which this powder is intended are Al2O3 pellets and Al2O 3 − B4C composite pellets for use as thermal insulator or burnable neutron absorbers, respectively. 1.2 The material described herein shall be particulate in nature.

  9. Association of Grade Configuration with School Climate for 7th and 8th Grade Students

    Science.gov (United States)

    Malone, Marisa; Cornell, Dewey; Shukla, Kathan

    2017-01-01

    Educational authorities have questioned whether middle schools provide the best school climate for 7th and 8th grade students, and proposed that other grade configurations such as K-8th grade schools may provide a better learning environment. The purpose of this study was to compare 7th and 8th grade students' perceptions of 4 key features of…

  10. High grade glioma: Imaging combined with pathological grade defines management and predicts prognosis

    International Nuclear Information System (INIS)

    Burnet, Neil G.; Lynch, Andrew G.; Jefferies, Sarah J.; Price, Stephen J.; Jones, Phil H.; Antoun, Nagui M.; Xuereb, John H.; Pohl, Ute

    2007-01-01

    Introduction: There is ambiguity in pathological grading of high grade gliomas within the WHO 2000 classification, especially those with predominant oligodendroglial differentiation. Patients and methods: All adult high grade gliomas treated radically, 1996-2005, were assessed. Cases in which pathology was grade III but radiology suggested glioblastoma (GBM) were classified as 'grade III/IV'; their pathology was reviewed. Results: Data from 245 patients (52 grade III, 18 grade III/IV, 175 GBM) were analysed using a Cox Proportional Hazards model. On pathology review, features suggestive of more aggressive behaviour were found in all 18 grade III/IV tumours. Oligodendroglial components with both necrosis and microvascular proliferation were present in 7. MIB-1 counts for the last 8 were all above 14%, mean 27%. Median survivals were: grade III 34 months, grade III/IV 10 months, GBM 11 months. Survival was not significantly different between grade III/IV and GBM. Patients with grade III/IV tumours had significantly worse outcome than grade III, with a hazard of death 3.7 times higher. Conclusions: The results highlight the current inconsistency in pathological grading of high grade tumours, especially those with oligodendroglial elements. Patients with histological grade III tumours but radiological appearances suggestive of GBM should be managed as glioblastoma

  11. Grade Inflation Marches On: Grade Increases from the 1990s to 2000s

    Science.gov (United States)

    Kostal, Jack W.; Kuncel, Nathan R.; Sackett, Paul R.

    2016-01-01

    Grade inflation threatens the integrity of college grades as indicators of academic achievement. In this study, we contribute to the literature on grade inflation by providing the first estimate of the size of grade increases at the student level between the mid-1990s and mid-2000s. By controlling for student characteristics and course-taking…

  12. The effect of various grading scales on student grade point averages.

    Science.gov (United States)

    Barnes, Kelli D; Buring, Shauna M

    2012-04-10

    To investigate changes in and the impact of grading scales from 2005 to 2010 and explore pharmacy faculty and student perceptions of whole-letter and plus/minus grading scales on cumulative grade point averages (GPAs) in required courses. Grading scales used in 2010 at the University of Cincinnati College of Pharmacy were retrospectively identified and compared to those used in 2005. Mean GPA was calculated using a whole-letter grading scale and a plus/minus grading scale to determine the impact of scales on GPA. Faculty members and students were surveyed regarding their perceptions of plus/minus grading. Nine unique grading scales were used throughout the curriculum, including plus/minus (64%) and whole-letter (21%) grading scales. From 2005 to 2010 there was transition from use of predominantly whole-letter scales to plus/minus grading scales. The type of grading scale used did not affect the mean cumulative GPA. Students preferred use of a plus-only grading scale while faculty members preferred use of a plus/minus grading scale. The transition from whole-letter grading to plus/minus grading in courses from 2005 to 2010 reflects pharmacy faculty members' perception that plus/minus grading allows for better differentiation between students' performances.

  13. Laparoscopic adrenalectomy: Gaining experience by graded approach

    Directory of Open Access Journals (Sweden)

    Dalvi Abhay

    2006-01-01

    Full Text Available INTRODUCTION: Laparoscopic adrenalectomy (LA has become a gold standard in management of most of the adrenal disorders. Though report on the first laparoscopic adrenalectomy dates back to 1992, there is no series of LA reported from India. Starting Feb 2001, a graded approach to LA was undertaken in our center. Till March 2006, a total of 34 laparoscopic adrenalectomies were performed with success. MATERIALS AND METHODS: The endocrinology department primarily evaluated all patients. Patients were divided into Group A - unilateral LA and Group B - bilateral LA (BLA. The indications in Group A were pheochromocytoma (n=7, Conn′s syndrome (n=3, Cushing′s adenoma (n=2, incidentaloma (n=2; and in Group B, Cushing′s disease (CD following failed trans-sphenoid pituitary surgery (n = 8; ectopic ACTH- producing Cushing′s syndrome (n=1 and congenital adrenal hyperplasia (CAH (n=1. The lateral transabdominal route was used. RESULTS: The age group varied from 12-54 years, with mean age of 28.21 years. Average duration of surgery in Group A was 166.43 min (40-270 min and 190 min (150- 310 min in Group B. Average blood loss was 136.93 cc (20-400 cc in Group A and 92.5 cc (40-260 cc in Group B. There was one conversion in each group. Mean duration of surgical stay was 1.8 days (1-3 days in Group A and 2.6 days (2-4 days in Group B. All the patients in both groups were cured of their illness. Three patients in Group B developed Nelson′s syndrome. The mean follow up was of 24.16 months (4-61 months. CONCLUSION: LA though technically demanding, is feasible and safe. Graded approach to LA is the key to success.

  14. Thermal and mechanical stresses in a functionally graded thick sphere

    International Nuclear Information System (INIS)

    Eslami, M.R.; Babaei, M.H.; Poultangari, R.

    2005-01-01

    In this paper, a general solution for the one-dimensional steady-state thermal and mechanical stresses in a hollow thick sphere made of functionally graded material is presented. The temperature distribution is assumed to be a function of radius, with general thermal and mechanical boundary conditions on the inside and outside surfaces of the sphere. The material properties, except Poisson's ratio, are assumed to vary along the radius r according to a power law function. The analytical solution of the heat conduction equation and the Navier equation lead to the temperature profile, radial displacement, radial stress, and hoop stress as a function of radial direction

  15. Energy education resources: Kindergarten through 12th grade

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Energy Education Resources: Kindergarten Through 12th Grade is published by the National Energy Information Center (NEIC) a service of the Energy Information Administration (EIA), to provide students, educators, and other information users, a list of generally available free or low-cost energy-related educational materials. Each entry includes the address, telephone number, and description of the organization and the energy-related materials available. Most of the entries also include Internet (Web) and electronic mail (E-Mail) addresses. Each entry is followed by a number, which is referenced in the subject index in the back of this book.

  16. Micromechanics of Composite Materials

    CERN Document Server

    Dvorak, George

    2013-01-01

    This book presents a broad exposition of analytical and numerical methods for modeling composite materials, laminates, polycrystals and other heterogeneous solids, with emphasis on connections between material properties and responses on several length scales, ranging from the nano and microscales to the macroscale. Many new results and methods developed by the author are incorporated into a rich fabric of the subject, which has been explored by several researchers over the last 40 years.   The first  part of the book reviews anisotropic elasticity theory, and then it describes the frequently used procedures and theorems for bounding and estimating overall properties, local fields and energy changes in elastic inhomogeneities, heterogeneous media, fiber composites and functionally graded materials.  Those are caused by mechanical loads and by phase eigenstrains, such as thermal, transformation and inelastic strains, and also by cavities and cracks.    Worked examples show that the eigendeformations may...

  17. DISCUS Ninth Grade, Earth Science.

    Science.gov (United States)

    Duval County School Board, Jacksonville, FL. Project DISCUS.

    Included are instructional materials designed for use with disadvantaged students who have a limited reading ability and poor command of English. The guide is the first volume of a two volume, one year program in earth science, and contains these four units and activities: Earth Materials, 8 activities; Weather, 10 activities; Water, 4 activities;…

  18. Processing and temperature-dependent properties of plasma-sprayed tungsten-stainless steel composites

    Science.gov (United States)

    Matějíček, Jiří; Boldyryeva, Hanna

    2009-12-01

    Tungsten-stainless steel (W+SS) composites and functionally graded materials (FGMs) have a potential application as joining material in plasma facing components for nuclear fusion devices. Here, tungsten provides the heat-resistant plasma facing armor, while stainless steel is the main structural material. The composite or FGM can reduce the stress concentration at the interface by providing a gradual transition. In this study, W+SS composites of various compositions were produced by water-stabilized plasma spraying. With the help of in-flight particle and plume diagnostics, powder injection was optimized for each material, and the feed rates were adjusted to account for different deposition efficiencies. The composition, structure, and thermal and mechanical properties of the coatings were characterized. As these materials are expected to function at elevated temperatures, the evolution of their properties with temperature was also studied.

  19. Processing and temperature-dependent properties of plasma-sprayed tungsten-stainless steel composites

    International Nuclear Information System (INIS)

    Matejicek, JirI; Boldyryeva, Hanna

    2009-01-01

    Tungsten-stainless steel (W+SS) composites and functionally graded materials (FGMs) have a potential application as joining material in plasma facing components for nuclear fusion devices. Here, tungsten provides the heat-resistant plasma facing armor, while stainless steel is the main structural material. The composite or FGM can reduce the stress concentration at the interface by providing a gradual transition. In this study, W+SS composites of various compositions were produced by water-stabilized plasma spraying. With the help of in-flight particle and plume diagnostics, powder injection was optimized for each material, and the feed rates were adjusted to account for different deposition efficiencies. The composition, structure, and thermal and mechanical properties of the coatings were characterized. As these materials are expected to function at elevated temperatures, the evolution of their properties with temperature was also studied.

  20. Interface Behavior in Functionally Graded Ceramics for the Magnetic Refrigeration: Numerical Modeling

    DEFF Research Database (Denmark)

    Jabbari, Masoud; Spangenberg, Jon; Hattel, Jesper Henri

    2013-01-01

    material is needed. Tape casting is a common process in producing functional ceramics, and it has recently been established for producing side-by-side (SBS) functionally graded ceramics (FGCs). The main goal of the present work is to study the multiple material flows in SBS tape casting and analyze......The active magnetic regenerator refrigerator is currently the most common magnetic refrigeration device for near room temperature applications, and it is driven by the magnetocaloric effect in the regenerator material. In order to make this efficient, a graded configuration of the magnetocaloric...

  1. Readability Grade Levels of Selected Navy Technical School Curricula. Focus on the Trained Person.

    Science.gov (United States)

    Losa, J. W.; And Others

    The U.S. Navy conducted a study to determine the readability grade level of materials used in its technical training schools curricula as a basis for (1) establishing minimal reading competencies for those schools, (2) identifying problem textual materials used in those schools, and (3) choosing additional school curricula for readability…

  2. Stress concentration analysis in functionally graded plates with elliptic holes under biaxial

    Directory of Open Access Journals (Sweden)

    Tawakol A. Enab

    2014-09-01

    Full Text Available Stress concentration factors (SCFs at the root of an elliptic hole in unidirectional functionally graded material (UDFGM plates under uniaxial and biaxial loads are predicted. ANSYS Parametric Design Language (APDL was used to build the finite element models for the plates and to run the analysis. A parametric study is performed for several geometric and material parameters such as the elliptic hole major axis to plate width ratio, the elliptical shape factor, the gradation direction of UDFGM. It is shown that, SCF in the finite plate can be significantly reduced by choosing the proper distribution of the functionally graded materials. The present study may provide designers an efficient way to estimate the hole effect on plate structures made of functionally graded materials.

  3. Formation of helium induced nanostructure 'fuzz' on various tungsten grades

    International Nuclear Information System (INIS)

    Baldwin, M.J.; Doerner, R.P.

    2010-01-01

    The response of a variety of W material grades to nanostructure 'fuzz' formation is explored. W targets are exposed to He or D 2 -0.2He plasmas in PISCES-B at 900-1320 K to below sputter threshold He + ions of energy 25-60 eV for up to 2.2 x 10 4 s. SEM and XPS reveal nanoscopic reorganization of the W surface to a layer of 'fuzz' of porosity ∼90% as determined by a 'fuzz' removal/weight loss method. The variability of 'fuzz' growth is examined at 1120 K for 1 h durations: SR, SC and doped W grades - La 2 O 3 (1% wt.), Re (5% and 10% wt.), and TiC (1.5% wt.) developed 2-3 μm thick 'fuzz' layers, while a VPS grade developed a layer 4 μm thick. An RC grade revealed additional 'fuzz' at deep (>100 μm) grain boundaries. However, heat treatment up to 1900 K produced reintegration of 'fuzz' with the bulk and He release at ∼1000 K and ∼1400-1800 K due to depopulation from vacancy complexes.

  4. Motivation in Physical Education classes of senior high school grades

    Directory of Open Access Journals (Sweden)

    Karen Cristina Chicati

    2008-06-01

    Full Text Available The aim of the present investigation was to make a diagnosis and analyze students’ motivation in Physical Education classes of the senior high school of the public school system in the city of Maringá, state of Paraná, Brazil. This descriptive research comprised a population of 12,889 students, males and females, with 15-to-17-year average age, enrolled in the three grades of senior high school. The sample comprised 240 students randomly selected from four schools: 60 students per school, 20 from each grade, 10 males and 10 females. A questionnaire constituted by 16 mixed questions was applied to the students. The data were analyzed through frequency and percentage calculus. The results demonstrated that Physical Education classes are not so highly motivated, once the students have been given the same contents since the first grades, prevailing sports. Command and open teaching have been the most frequently used methodology, despite most of the students answering that they do what they want to in class. Evaluation comprises attendance and theoretical/practical classes. The students demonstrated a strong interest in classes, but those who are not so much interested answered that the classes were demotivating, besides backing appropriate materials and space. Thus it may be concluded that students motivation in Physical Education classes in the senior high school grades is not so clear.

  5. Strategic Materials

    National Research Council Canada - National Science Library

    Buhler, Carl; Burke, Adrian; Davis, Kirk; Gerhard, Michelle; Heil, Valerie; Hulse, Richard; Kwong, Ralph; Mahoney, Michael; Moran, Scott; Peek, Michael

    2006-01-01

    Some materials possess greater value than others. Materials that provide essential support for the nation's economic viability or enable critical military capabilities warrant special attention in security studies...

  6. New similarity search based glioma grading

    Energy Technology Data Exchange (ETDEWEB)

    Haegler, Katrin; Brueckmann, Hartmut; Linn, Jennifer [Ludwig-Maximilians-University of Munich, Department of Neuroradiology, Munich (Germany); Wiesmann, Martin; Freiherr, Jessica [RWTH Aachen University, Department of Neuroradiology, Aachen (Germany); Boehm, Christian [Ludwig-Maximilians-University of Munich, Department of Computer Science, Munich (Germany); Schnell, Oliver; Tonn, Joerg-Christian [Ludwig-Maximilians-University of Munich, Department of Neurosurgery, Munich (Germany)

    2012-08-15

    MR-based differentiation between low- and high-grade gliomas is predominately based on contrast-enhanced T1-weighted images (CE-T1w). However, functional MR sequences as perfusion- and diffusion-weighted sequences can provide additional information on tumor grade. Here, we tested the potential of a recently developed similarity search based method that integrates information of CE-T1w and perfusion maps for non-invasive MR-based glioma grading. We prospectively included 37 untreated glioma patients (23 grade I/II, 14 grade III gliomas), in whom 3T MRI with FLAIR, pre- and post-contrast T1-weighted, and perfusion sequences was performed. Cerebral blood volume, cerebral blood flow, and mean transit time maps as well as CE-T1w images were used as input for the similarity search. Data sets were preprocessed and converted to four-dimensional Gaussian Mixture Models that considered correlations between the different MR sequences. For each patient, a so-called tumor feature vector (= probability-based classifier) was defined and used for grading. Biopsy was used as gold standard, and similarity based grading was compared to grading solely based on CE-T1w. Accuracy, sensitivity, and specificity of pure CE-T1w based glioma grading were 64.9%, 78.6%, and 56.5%, respectively. Similarity search based tumor grading allowed differentiation between low-grade (I or II) and high-grade (III) gliomas with an accuracy, sensitivity, and specificity of 83.8%, 78.6%, and 87.0%. Our findings indicate that integration of perfusion parameters and CE-T1w information in a semi-automatic similarity search based analysis improves the potential of MR-based glioma grading compared to CE-T1w data alone. (orig.)

  7. New similarity search based glioma grading.

    Science.gov (United States)

    Haegler, Katrin; Wiesmann, Martin; Böhm, Christian; Freiherr, Jessica; Schnell, Oliver; Brückmann, Hartmut; Tonn, Jörg-Christian; Linn, Jennifer

    2012-08-01

    MR-based differentiation between low- and high-grade gliomas is predominately based on contrast-enhanced T1-weighted images (CE-T1w). However, functional MR sequences as perfusion- and diffusion-weighted sequences can provide additional information on tumor grade. Here, we tested the potential of a recently developed similarity search based method that integrates information of CE-T1w and perfusion maps for non-invasive MR-based glioma grading. We prospectively included 37 untreated glioma patients (23 grade I/II, 14 grade III gliomas), in whom 3T MRI with FLAIR, pre- and post-contrast T1-weighted, and perfusion sequences was performed. Cerebral blood volume, cerebral blood flow, and mean transit time maps as well as CE-T1w images were used as input for the similarity search. Data sets were preprocessed and converted to four-dimensional Gaussian Mixture Models that considered correlations between the different MR sequences. For each patient, a so-called tumor feature vector (= probability-based classifier) was defined and used for grading. Biopsy was used as gold standard, and similarity based grading was compared to grading solely based on CE-T1w. Accuracy, sensitivity, and specificity of pure CE-T1w based glioma grading were 64.9%, 78.6%, and 56.5%, respectively. Similarity search based tumor grading allowed differentiation between low-grade (I or II) and high-grade (III) gliomas with an accuracy, sensitivity, and specificity of 83.8%, 78.6%, and 87.0%. Our findings indicate that integration of perfusion parameters and CE-T1w information in a semi-automatic similarity search based analysis improves the potential of MR-based glioma grading compared to CE-T1w data alone.

  8. Finite deformations of functionally graded shell under outer pressure with steady state temperature

    Science.gov (United States)

    Sharma, Sanjeev; Panchal, Rekha; Sahni, Manoj; Sharma, Richa

    2017-10-01

    In this paper, finite elastic and plastic stresses have been determined for functionally graded shell using the concepts of transition theory and generalized measure of strain i.e. nonlinear terms in the displacements are also considered while in classical theory only infinitesimal strain theory concept has been applied. In this problem of spherical shell, temperature has been applied at the internal surface while pressure is considered to be applied at the external surface. From the detailed analysis, it has been noticed that temperature and pressure have significant effects on functionally graded shell. In this paper, it is found that external pressure required for the fully plastic state from initial yielding is on the higher side for the shell made up of highly functionally graded material as compared to the shell made up of less functionally graded material.

  9. Is the Sky Falling? Grade Inflation and the Signaling Power of Grades.

    Science.gov (United States)

    Pattison, Evangeleen; Grodsky, Eric; Muller, Chandra

    2013-06-01

    Grades are the fundamental currency of our educational system; they signal academic achievement and non-cognitive skills to parents, employers, postsecondary gatekeepers, and students themselves. Grade inflation compromises the signaling value of grades, undermining their capacity to achieve the functions for which they are intended. We challenge the 'increases in grade point average' definition of grade inflation and argue that grade inflation must be understood in terms of the signaling power of grades. Analyzing data from four nationally representative samples, we find that in the decades following 1972: (a) grades have risen at high schools and dropped at four-year colleges, in general, and selective four-year institutions, in particular; and (b) the signaling power of grades has attenuated little, if at all.

  10. Low-grade and high-grade endometrial stromal sarcoma: A National Cancer Database study.

    Science.gov (United States)

    Seagle, Brandon-Luke L; Shilpi, Arunima; Buchanan, Samuel; Goodman, Chelain; Shahabi, Shohreh

    2017-08-01

    To provide refined prognostic information from large cohorts of women with low-grade or high-grade endometrial stromal sarcoma (ESS). We performed an observational retrospective cohort analysis of women diagnosed with low-grade or high-grade ESS from the 1998-2013 National Cancer Database. Kaplan-Meier and multivariable accelerated failure time survival analyses were performed to identify prognostic factors after multiple imputation of missing data. Recursive partitioning methods were used to rank prognostic factors in high-grade ESS. Matched cohort analyses were performed to hypothesis-test effects of adjuvant treatments. We identified 2414 and 1383 women with low-grade or high-grade ESS, respectively. Women with high-grade ESS had markedly decreased survival compared to women with low-grade ESS (five-year survival (95% CI): 32.6 (30.1-35.3%) versus 90.5% (89.3-91.8%), PTR) (95% CI): 1.36 (1.17-1.58), PTR (95% CI): 1.57 (1.32-1.87), P<0.001) were associated with increased survival for high-grade ESS. The contrasting excellent versus poor prognosis of low-grade versus high-grade ESS, respectively, was confirmed. The best treatment of high-grade ESS is early and complete surgical resection including lymphadenectomy. Adjuvant chemotherapy and radiotherapy may increase survival of women with high-grade ESS. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. The opinion of gynecologists on the management of early-stage, high-grade endometrioid endometrial cancer

    NARCIS (Netherlands)

    Geels, Y.P.; Putten, L.J. van der; Steen-Banasik, E.M. van der; Snijders, M.P.M.L.; Massuger, L.F.A.G.; Pijnenborg, J.M.A.

    2015-01-01

    PURPOSE OF INVESTIGATION: There is no consensus on the management of Stage I endometrioid endometrial cancer (EEC) with grade 3 histology. This study evaluates the opinion of gynecologists in The Netherlands on the management of Stage I, grade 3 EEC. MATERIALS AND METHODS: Members of the Dutch

  12. Development of Society in the United States. American Civilization, Resource Unit II, Grade 10. Providence Social Studies Curriculum Project.

    Science.gov (United States)

    Providence Public Schools, RI.

    GRADES OR AGES: Grades 10 and 11. SUBJECT MATTER: Social studies; United States civilization. ORGANIZATION AND PHYSICAL APPEARANCE: The major portion of the guide is divided into six subunits, each of which is laid out in three columns, one each for topics, activities, and materials. Other sections are in list form. The guide is mimeographed and…

  13. Grading of Extraction and Its Relationship with Post-operative Pain and Trismus, along with Proposed Grading for Trismus

    Science.gov (United States)

    Vashisth, Shirin; Mishra, Saurabh; Singh, Surendra Pratap; Sharma, Shalini

    2014-01-01

    Background: Extraction of mandibular third molars are somewhat a matter of interest because of its malpositioning , curved roots, proximity to vital structures due to this the procedure is often associated with post operative complications like pain and trismus. The extraction of third molar was classified in four grads according to the difficulty of the procedure. Aims: The purpose of this paper is to find any significant relationship between grading of extraction and post operative complications like pain and trismus. Materials and Methods: A total number of 180 patients need to go for extraction of third molar was included in the study. The variables taken into account were grading of extraction, pain six hour post operatively trismus one day after extraction, and trismus five day after extraction. The four grades of extractions as described by Parent in 1974 were statistically analyzed by computing pearson product moment correlation coefficient with post operative pain and trismus first and fifth day to find any co relation between them. Results: The grading of extraction was found significantly correlated with post operative pain, trismus one day after and fifth day of surgery. PMID:25121055

  14. 7 CFR 51.3412 - Unusable material.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Unusable material. 51.3412 Section 51.3412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Potatoes for Processing 1 § 51.3412 Unusable material. “Unusable Material” consists...

  15. Bibliography of Legal Education Materials. PDE Working Paper.

    Science.gov (United States)

    Pennsylvania State Dept. of Education, Harrisburg. Bureau of General and Academic Education.

    This list is of print and non-print materials that may have application to legal education for elementary and secondary grades. Types of print materials include student texts, periodicals, and pamphlets, curriculum materials, and books, both hardbound and paperback. Non-print materials include sound films and filmstrips and pre-recorded tapes.…

  16. Four-Dimensional Graded Consciousness

    Science.gov (United States)

    Jonkisz, Jakub; Wierzchoń, Michał; Binder, Marek

    2017-01-01

    Both the multidimensional phenomenon and the polysemous notion of consciousness continue to prove resistant to consistent measurement and unambiguous definition. This is hardly surprising, given that there is no agreement even as regards the most fundamental issues they involve. One of the basic disagreements present in the continuing debate about consciousness pertains to its gradational nature. The general aim of this article is to show how consciousness might be graded and multidimensional at the same time. We therefore focus on the question of what it is, exactly, that is or could be graded in cases of consciousness, and how we can measure it. Ultimately, four different gradable aspects of consciousness will be described: quality, abstractness, complexity and usefulness, which belong to four different dimensions, these being understood, respectively, as phenomenal, semantic, physiological, and functional. Consequently, consciousness may be said to vary with respect to phenomenal quality, semantic abstraction, physiological complexity, and functional usefulness. It is hoped that such a four-dimensional approach will help to clarify and justify claims about the hierarchical nature of consciousness. The approach also proves explanatorily advantageous, as it enables us not only to draw attention to certain new and important differences in respect of subjective measures of awareness and to justify how a given creature may be ranked higher in one dimension of consciousness and lower in terms of another, but also allows for innovative explanations of a variety of well-known phenomena (amongst these, the interpretations of blindsight and locked-in syndrome will be briefly outlined here). Moreover, a 4D framework makes possible many predictions and hypotheses that may be experimentally tested (We point out a few such possibilities pertaining to interdimensional dependencies). PMID:28377738

  17. Pembuatan Biodiesel dari Cpo Off Grade Menggunakan Reaktor Membran (Variasi Katalis dan Fraksi Mol Umpan

    OpenAIRE

    Vovilya, Enang '; ', Syarfi '; Saputra, Edy '

    2015-01-01

    Membrane reactor is an alternative technology that is used in the manufacture of biodiesel, one of the advantages that the reaction and separation process takes place in a single stage simultaneous. This research aims to study the effect of the variation of the catalyst and mole ratio feed CPO off grade - methanol in biodiesel production, a pretreatment process performed on the raw materials that aim to reduce the FFA content CPO off grade, the results obtained pretreatment FFA content of 0.7...

  18. Halo effects in grading student projects.

    Science.gov (United States)

    Dennis, Ian

    2007-07-01

    Halo effects in rating specific pieces of work, as in educational grading, have received little attention. Grades awarded by 2 independent graders to undergraduate projects were analyzed with a correlated uniqueness model. Grades showed substantial halo despite being awarded by expert assessors at the time of reading the work. There was greater halo between different grades applying to the same section of the project than between grades applying to different sections. Supervisors who had regular contact with the student whose work they were grading showed no more halo than other graders. More reliable graders showed less within-section halo than graders of lower reliability but equal between-sections halo. The halo effects observed cannot be entirely attributable to a unitary general impression.

  19. Does Relative Grading help Male Students?

    DEFF Research Database (Denmark)

    Czibor, Eszter; Onderstal, Sander; Sloof, Randolph

    The provision of non-pecuniary incentives in education is a topic that has received much scholarly attention lately. Our paper contributes to this discussion by investigating the effectiveness of grade incentives in increasing student performance. We perform a direct comparison of the two most...... for male students than absolute grading. In the full sample, we find weak support for our hypothesis. Among the more motivated students we find evidence that men indeed score significantly higher on the test when graded on a curve. Female students, irrespective of their motivation, do not increase...... their scores under relative grading. Since women slightly outperform men under absolute grading, grading on a curve actually narrows the gender gap in performance....

  20. Processing of low-grade uranium ores

    International Nuclear Information System (INIS)

    Michel, P.

    1975-01-01

    Four types of low grade ores are studied. Low grade ores which must be extracted because they are enclosed in a normal grade deposit. Heap leaching is the processing method which is largely used. It allows to obtain solutions or preconcentrates which may be delivered at the nearest plant. Normal grade ores contained in a low amplitude deposit which can be processed using leaching as far as the operation does not need any large expensive equipment. Medium grade ores in medium amplitude deposits to which a simplified conventional process can be applied using fast heap leaching. Low grade ores in large deposits. The processing possibilities leading to use in place leaching are explained. The operating conditions of the method are studied (leaching agent, preparation of the ore deposit to obtain a good tightness with regard to the hydrological system and to have a good contact between ore and reagent) [fr

  1. Processing of low grade uranium ores

    International Nuclear Information System (INIS)

    Michel, P.

    1978-10-01

    Four types of low-grade ores are studied: (1) Low-grade ores that must be extracted because they are enclosed in a normal-grade deposit. Heap leaching is the processing method which is largely used. (2) Normal-grade ores contained in low-amplitude deposits. They can be processed using in-place leaching as far as the operation does not need any large and expensive equipment. (3) Medium-grade ores in medium-amplitude deposits. A simplified conventional process can be applied using fast heap leaching. (4) Low-grade ores in large deposits. The report explains processing possibilities leading in most cases to the use of in-place leaching. The operating conditions of this method are laid out, especially the selection of the leaching agents and the preparation of the ore deposit

  2. Peculiarities of Evaluation of Motor Abilities Development in 10th-11th-Grade Boys

    OpenAIRE

    В. М. Старченко

    2016-01-01

    The purpose of the research is to determine the main indicators of motor abilities development in the 10th-11th-grade boys. Materials and methods. To achieve the tasks set, the research relied on the following methods: analysis of scientific and methodological literature, pedagogical testing and methods of mathematical statistics. The participants in the study were 28 high-school boys (14 boys of the 10th-grade and 14 boys of the 11th-grade). Conclusions. The general level of motor re...

  3. Grades and Ranking: When Tenure Affects Assessment

    OpenAIRE

    Jean Filetti; Mary Wright; William M. King

    2010-01-01

    This article examines how a faculty member's status-'either tenured or tenure-track-'might affect the grades assigned to students in a writing class. We begin with a brief review of the research surrounding faculty to student assessment practices and follow with specific controversies regarding faculty motivation pertaining to grading practices. We interpret the grade distributions of tenured and tenure-track faculty members teaching a sophomore-level writing course in an English Department...

  4. Dual Energy Spectral CT Imaging for Colorectal Cancer Grading: A Preliminary Study.

    Directory of Open Access Journals (Sweden)

    Hong-Xia Gong

    Full Text Available To assess the diagnostic value of dual energy spectral CT imaging for colorectal cancer grading using the quantitative iodine density measurements in both arterial phase (AP and venous phase (VP.81 colorectal cancer patients were divided into two groups based on their pathological findings: a low grade group including well (n = 13 and moderately differentiated cancer (n = 24, and a high grade group including poorly differentiated (n = 42 and signet ring cell cancer (n = 2. Iodine density (ID in the lesions was derived from the iodine-based material decomposition (MD image and normalized to that in the psoas muscle to obtain normalized iodine density (NID. The difference in ID and NID between AP and VP was calculated.The ID and NID values of the low grade cancer group were, 14.65 ± 3.38 mg/mL and 1.70 ± 0.33 in AP, and 21.90 ± 3.11 mg/mL and 2.05 ± 0.32 in VP, respectively. The ID and NID values for the high grade cancer group were 20.63 ± 3.72 mg/mL and 2.95 ± 0.72 in AP, and 26.27 ± 3.10mg/mL and 3.51 ± 1.12 in VP, respectively. There was significant difference for ID and NID between the low grade and high grade cancer groups in both AP and VP (all p<0.001. ROC analysis indicated that NID of 1.92 in AP provided 70.3% sensitivity and 97.7% specificity in differentiating low grade cancer from high grade cancer.The quantitative measurement of iodine density in AP and VP can provide useful information to differentiate low grade colorectal cancer from high grade colorectal cancer with NID in AP providing the greatest diagnostic value.

  5. Multiparametric analysis of magnetic resonance images for glioma grading and patient survival time prediction

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, Benjamin (Dept. of Circulation and Medical Imaging, NTNU, Trondheim (Norway)), email: benjamin.garzon@ntnu.no; Emblem, Kyrre E. (The Interventional Center, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway); Dept. of Radiology, MGH-HST AA Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States)); Mouridsen, Kim (Center of Functionally Integrative Neuroscience, Aarhus Univ., Aarhus (Denmark)); Nedregaard, Baard; Due-Toennessen, Paulina; Nome, Terje; Hald, John K. (Dept. of Radiology and Nuclear Medicine, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway)); Bjoernerud, Atle (The Interventional Center, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway)); Haaberg, Asta K. (Dept. of Circulation and Medical Imaging, NTNU, Trondheim (Norway); Dept. of Medical Imaging, St Olav' s Hospital, Trondheim (Norway)); Kvinnsland, Yngve (NordicImagingLab, Bergen (Norway))

    2011-11-15

    Background. A systematic comparison of magnetic resonance imaging (MRI) options for glioma diagnosis is lacking. Purpose. To investigate multiple MR-derived image features with respect to diagnostic accuracy in tumor grading and survival prediction in glioma patients. Material and Methods. T1 pre- and post-contrast, T2 and dynamic susceptibility contrast scans of 74 glioma patients with histologically confirmed grade were acquired. For each patient, a set of statistical features was obtained from the parametric maps derived from the original images, in a region-of-interest encompassing the tumor volume. A forward stepwise selection procedure was used to find the best combinations of features for grade prediction with a cross-validated logistic model and survival time prediction with a cox proportional-hazards regression. Results. Presence/absence of enhancement paired with kurtosis of the FM (first moment of the first-pass curve) was the feature combination that best predicted tumor grade (grade II vs. grade III-IV; median AUC 0.96), with the main contribution being due to the first of the features. A lower predictive value (median AUC = 0.82) was obtained when grade IV tumors were excluded. Presence/absence of enhancement alone was the best predictor for survival time, and the regression was significant (P < 0.0001). Conclusion. Presence/absence of enhancement, reflecting transendothelial leakage, was the feature with highest predictive value for grade and survival time in glioma patients

  6. Multiparametric analysis of magnetic resonance images for glioma grading and patient survival time prediction

    International Nuclear Information System (INIS)

    Garzon, Benjamin; Emblem, Kyrre E.; Mouridsen, Kim; Nedregaard, Baard; Due-Toennessen, Paulina; Nome, Terje; Hald, John K.; Bjoernerud, Atle; Haaberg, Asta K.; Kvinnsland, Yngve

    2011-01-01

    Background. A systematic comparison of magnetic resonance imaging (MRI) options for glioma diagnosis is lacking. Purpose. To investigate multiple MR-derived image features with respect to diagnostic accuracy in tumor grading and survival prediction in glioma patients. Material and Methods. T1 pre- and post-contrast, T2 and dynamic susceptibility contrast scans of 74 glioma patients with histologically confirmed grade were acquired. For each patient, a set of statistical features was obtained from the parametric maps derived from the original images, in a region-of-interest encompassing the tumor volume. A forward stepwise selection procedure was used to find the best combinations of features for grade prediction with a cross-validated logistic model and survival time prediction with a cox proportional-hazards regression. Results. Presence/absence of enhancement paired with kurtosis of the FM (first moment of the first-pass curve) was the feature combination that best predicted tumor grade (grade II vs. grade III-IV; median AUC 0.96), with the main contribution being due to the first of the features. A lower predictive value (median AUC = 0.82) was obtained when grade IV tumors were excluded. Presence/absence of enhancement alone was the best predictor for survival time, and the regression was significant (P < 0.0001). Conclusion. Presence/absence of enhancement, reflecting transendothelial leakage, was the feature with highest predictive value for grade and survival time in glioma patients

  7. Improving listening in the elementary grades.

    Science.gov (United States)

    Meinders, P M; Byers, V W

    1981-11-01

    A single stratagem was taught to 36 students: 12 each in the second grade, the fourth grade, and the sixth grade, to improve their listening skills. The basic six stratagem taught the children how to ask who, what, when, where, why, and how questions. The children were seen three times a week in groups of six. The results of a pre - post test showed statistically significant improvement for the children in the listening program. The second-grade group showed an average improvement of 3.92 correct answers, a 23% improvement. The fourth-grade group showed an average improvement of 5.75 correct answers, a 23% improvement. The sixth-grade group showed an average improvement of 4.55 correct answers, a 12% improvement. Their classmates in the fourth and sixth grades, who also took the pre - post test, show no improvement in their pre - post test scores. The second-grade classroom children showed a significant improvement of 1.55 correct answers, which was a 9% improvement. The listening skills of children in the elementary grades can be improved through a direct teaching of a specific stratagem in a small group setting.

  8. Resistor grading at the NSC Pelletron

    International Nuclear Information System (INIS)

    Narayanan, M.M.; Jayan, K.M.; Ahuja, R.; Chopra, S.; Kanjilal, D.

    1997-01-01

    The cheap and robust voltage grading system, based on the point to plane corona discharge, provided in the Nuclear Science Centre (NSC) Pelletron accelerator is replaced by a grading system using high-voltage high-value resistors with appropriate spark protection for the resistors. The accelerator has been operating for more than a year now with the new grading system and the performance of the resistors has been quite satisfactory. A brief introduction followed by the work done at NSC is given. The main features and the performance of the voltage grading at NSC with resistors are also included. (author). 8 refs., 1 fig

  9. Changes and Trends in the Pallet Industry: The Use of New Wood Materials

    Science.gov (United States)

    Robert J. Bush; Philip A. Araman

    1998-01-01

    Wood has dominated the pallet industry as its principal raw material since palletized material handling began. Pallet production and use grew dramatically after World War II and wood remained the material of choice. Throughout this period the pallet industry has been an important market for lower grades of hardwood lumber and cants. Today, the demand for pallet grade...

  10. Semisolid forming of S48C steel grade

    Science.gov (United States)

    Plata, Gorka; Lozares, Jokin; Azpilgain, Zigor; Hurtado, Iñaki; Loizaga, Iñigo; Idoyaga, Zuriñe

    2017-10-01

    Steel production and component manufacturing industries have to face the challenge of globalization, trying to overcome the economic pressure to remain competitive. Moreover, the lightweighting trend of the latter years implies an even higher challenge to maintain the steel use. Therefore, advanced manufacturing processes will be the cornerstone. In this field, Semisolid forming (SSF) has demonstrated the capability of obtaining complex geometries and saving raw material and energy. Despite it is complicated the SSF of sound components, in Mondragon Unibertsitatea it has been successfully demonstrated the capability of producing strong enough automotive components with 42CrMo4 steel grade. In this work, we demonstrate the capability of SSF S48C steel grade with great mechanical properties.

  11. Levy Solution for Buckling Analysis of Functionally Graded Rectangular Plates

    Science.gov (United States)

    Mohammadi, Meisam; Saidi, Ali Reza; Jomehzadeh, Emad

    2010-04-01

    In this article, an analytical method for buckling analysis of thin functionally graded (FG) rectangular plates is presented. It is assumed that the material properties of the plate vary through the thickness of the plate as a power function. Based on the classical plate theory (Kirchhoff theory), the governing equations are obtained for functionally graded rectangular plates using the principle of minimum total potential energy. The resulting equations are decoupled and solved for rectangular plate with different loading conditions. It is assumed that the plate is simply supported along two opposite edges and has arbitrary boundary conditions along the other edges. The critical buckling loads are presented for a rectangular plate with different boundary conditions, various powers of FGM and some aspect ratios.

  12. 3D Printed Composite-Z and Graded-Z Radiation Shields (CoGZ-Rad), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Composite-Z and Graded-Z Radiation Shields (CoGZ-Rad) uses novel multi-material 3D printing techniques to fabricate a cost-effective and lightweight radiation...

  13. Peer Victimization in Fifth Grade and Health in Tenth Grade

    Science.gov (United States)

    Elliott, Marc N.; Klein, David J.; Tortolero, Susan R.; Mrug, Sylvie; Peskin, Melissa F.; Davies, Susan L.; Schink, Elizabeth T.; Schuster, Mark A.

    2014-01-01

    BACKGROUND AND OBJECTIVES: Children who experience bullying, a type of peer victimization, show worse mental and physical health cross-sectionally. Few studies have assessed these relationships longitudinally. We examined longitudinal associations of bullying with mental and physical health from elementary to high school, comparing effects of different bullying histories. METHODS: We analyzed data from 4297 children surveyed at 3 time points (fifth, seventh, and tenth grades) in 3 cities. We used multivariable regressions to test longitudinal associations of bullying with mental and physical health by comparing youth who experienced bullying in both the past and present, experienced bullying in the present only, experienced bullying in the past only, or did not experience bullying. RESULTS: Bullying was associated with worse mental and physical health, greater depression symptoms, and lower self-worth over time. Health was significantly worse for children with both past and present bullying experiences, followed by children with present-only experiences, children with past-only experiences, and children with no experiences. For example, 44.6% of children bullied in both the past and present were at the lowest decile of psychosocial health, compared with 30.7% of those bullied in the present only (P = .005), 12.1% of those bullied in the past only (P bullied (P < .001). CONCLUSIONS: Both chronic and current bullying are associated with substantially worse health. Clinicians who recognize bullying when it first starts could intervene to reverse the downward health trajectory experienced by youth who are repeated targets. PMID:24534401

  14. To Grade or Not to Grade: Student Perceptions of the Effects of Grading a Course in Work-Integrated Learning

    Science.gov (United States)

    Reddan, Gregory

    2013-01-01

    This paper aims to demonstrate the benefits of introducing the typical course grading process to a work-integrated learning course in exercise science in order to motivate students to produce their best efforts in assessment tasks relevant to their future employability. The course had incorporated a non-graded pass/fail system of assessment since…

  15. Materials Chemistry

    CERN Document Server

    Fahlman, Bradley D

    2011-01-01

    The 2nd edition of Materials Chemistry builds on the strengths that were recognized by a 2008 Textbook Excellence Award from the Text and Academic Authors Association (TAA). Materials Chemistry addresses inorganic-, organic-, and nano-based materials from a structure vs. property treatment, providing a suitable breadth and depth coverage of the rapidly evolving materials field. The 2nd edition continues to offer innovative coverage and practical perspective throughout. After briefly defining materials chemistry and its history, seven chapters discuss solid-state chemistry, metals, semiconducting materials, organic "soft" materials, nanomaterials, and materials characterization. All chapters have been thoroughly updated and expanded with, for example, new sections on ‘soft lithographic’ patterning, ‘click chemistry’ polymerization, nanotoxicity, graphene, as well as many biomaterials applications. The polymer and ‘soft’ materials chapter represents the largest expansion for the 2nd edition. Each ch...

  16. Mode Shape Analysis of Multiple Cracked Functionally Graded Timoshenko Beams

    Directory of Open Access Journals (Sweden)

    Tran Van Lien

    Full Text Available Abstract The present paper addresses free vibration of multiple cracked Timoshenko beams made of Functionally Graded Material (FGM. Cracks are modeled by rotational spring of stiffness calculated from the crack depth and material properties vary according to the power law throughout the beam thickness. Governing equations for free vibration of the beam are formulated with taking into account actual position of the neutral plane. The obtained frequency equation and mode shapes are used for analysis of the beam mode shapes in dependence on the material and crack parameters. Numerical results validate usefulness of the proposed herein theory and show that mode shapes are good indication for detecting multiple cracks in Timoshenko FGM beams.

  17. Free Vibration Analysis of Multiple Cracked Functionally Graded Timoshenko Beams

    Directory of Open Access Journals (Sweden)

    Tran Van Lien

    Full Text Available Abstract In this paper, authors present the study of free vibration of bending multiple cracked functionally graded material (FGM beam. Vibration equations of multiple cracked FGM beam were established by using the rotational spring model of cracks, dynamic stiffness method (DSM and actual position of neutral plane. The frequency equation obtained was in a simple form, that provides an effective approach to study not only free vibration of the beams but also inverse problems like identification of material and crack parameters in structure. The obtained numerical results show good agreement with other previous published results. Thence, numerical computation has been carried out to investigate the effect of each crack, the number of cracks, material and geometric parameters on the natural frequencies of multiple cracked Timoshenko FGM beams.

  18. Performance Analysis of Functionally Graded Coatings in Contact with Cylindrical Rollers

    Directory of Open Access Journals (Sweden)

    Reza Jahedi

    2015-01-01

    Full Text Available This work presents finite element analysis (FEA and results for rolling contact of a cylindrical roller on an elastic substrate coated by functionally graded material (FGM. The rolling process and the graded coating material property and layers arrangement are modeled using finite element codes which lead to a new methodology. This novel methodology provides a trend in determining surface contact stresses, deformations, contact zones, and energy dissipation through the contact area. Effects of stiffness ratio, friction, and exponentially variation of material property on the contact stresses and deformations are studied. Some of the results are verified with analytical solutions. The study results may be beneficial in graded coated cylindrical components analysis against rolling contact failure and wear.

  19. Delamination Analysis of a Multilayered Two-Dimensional Functionally Graded Cantilever Beam

    Science.gov (United States)

    Rizov, V.

    2017-11-01

    Delamination fracture behaviour of a multilayered two-dimensional functionally graded cantilever beam is analyzed in terms of the strain energy release rate. The beam is made of an arbitrary number of layers. Perfect adhesion is assumed between layers. Each layer has individual thickness and material properties. Besides, the material is two-dimensional functionally graded in the cross-section of each layer. There is a delamination crack located arbitrary between layers. The beam is loaded by a bending moment applied at the free end of the lower crack arm. The upper crack arm is free of stresses. The solution to strain energy release rate derived is applied to investigate the influence of the crack location and the material gradient on the delamination fracture. The results obtained can be used to optimize the multilayered two-dimensional functionally graded beam structure with respect to the delamination fracture behaviour.

  20. Enhanced safety in the storage of fissile materials

    International Nuclear Information System (INIS)

    Williams, G.E.; Alvares, N.J.

    1979-01-01

    A ''plastic-like'' supporting material impregnated with a neutron-absorbing agent that is suitable for ''lining'' the inner surfaces of fissile-material storage containers was fabricated. The material consists, by weight, of 50% food-grade borax, 25% coal tar, and 25% epoxy resin. It costs much less than commercially available materials, can absorb enough neutrons to isolate units of fissile material, and possesses such structural qualities as flexibility and machinability. Properties and performance of the material are discussed

  1. Superhard nanophase materials for rock drilling applications

    Energy Technology Data Exchange (ETDEWEB)

    Sadangi, R.K.; Voronov, O.A.; Tompa, G.S. [Diamond Materials Inc., Pisctaway, NJ (United States); Kear, B.H. [Rutgers Univ., Piscataway, NJ (United States)

    1997-12-31

    Diamond Materials Incorporated is developing new class of superhard materials for rock drilling applications. In this paper, we will describe two types of superhard materials, (a) binderless polycrystalline diamond compacts (BPCD), and (b) functionally graded triphasic nanocomposite materials (FGTNC). BPCDs are true polycrystalline diamond ceramic with < 0.5 wt% binders and have demonstrated to maintain their wear properties in a granite-log test even after 700{degrees}C thermal treatment. FGTNCs are functionally-graded triphasic superhard material, comprising a nanophase WC/Co core and a diamond-enriched surface, that combine high strength and toughness with superior wear resistance, making FGTNC an attractive material for use as roller cone stud inserts.

  2. Preparation of planar graded refractive index nanocomposites using microfluidics

    International Nuclear Information System (INIS)

    Baah, David; Tigner, Julaunica; Bean, Kala; Britton, Bernard; Walker, Nicole; Henderson, Gwynetta; Floyd-Smith, Tamara

    2011-01-01

    Highlights: → Preparation of planar graded refractive index nanocomposites using microfluidics → Microfluidic channels dispersed nanoparticles achieving high fidelity profiles. → A dispersion of rutile TiO 2 nanoparticles created optically functional materials. → A Δn of 0.1 and an optically transparent material were achieved. - Abstract: In this paper, a microfluidics-based approach for preparing graded refractive index polymer composites is described. These graded refractive index polymers have potential for optical applications due to the fidelity and variety of the profiles that can be achieved using microfluidics technology. In this study, microfluidic devices, fabricated in poly(dimethylsiloxane) (PDMS), dispersed TiO 2 nanoparticles in a prepolymer solution consisting of low molecular weight poly(ethylene glycol diacrylate) (PEGDA). Following dispersion of the particles to produce a controlled gradient profile in the liquid pre-polymer solution, UV light polymerized the solution to produce graded refractive index nanocomposites. Initially, as a means of understanding the flow parameters and straightforward elucidation of the gradient profiles, fluorescent polystyrene nanoparticles were dispersed. After a general method for dispersing nanoparticles was developed, anatase TiO 2 was synthesized and dispersed to produce nanocomposites. However, transmission electron microscope (TEM) analysis and optical microscopy revealed that the particles were agglomerated and, consequently, the amount of TiO 2 that would remain in the pre-polymer solution was severely limited. To address the problem of particle settling, rutile TiO 2 was synthesized using a different precursor and dispersed. Rutile TiO 2 was chosen because the synthesis scheme was expected to yield a well-dispersed solution. Also, rutile TiO 2 is less likely to cause interference with the light used both for the polymerization and for demonstrating the material for optical applications. Following

  3. The Impact of Early Exposure of Eighth Grade Math Standards on End of Grade Assessments

    Science.gov (United States)

    Robertson, Tonjai E.

    2016-01-01

    The purpose of this study was to examine the Cumberland County Schools district-wide issue surrounding the disproportional performance of eighth grade Math I students' proficiency scores on standardized end-of-grade and end-of-course assessments. The study focused on the impact of the school district incorporating eighth grade math standards in…

  4. Are Flunkers Social Outcasts? A Multilevel Study of Grade Retention Effects on Same-Grade Friendships

    Science.gov (United States)

    Demanet, Jannick; Van Houtte, Mieke

    2016-01-01

    We examine the association between grade retention and the number of same-grade friendships. Moreover, we investigate the effect of a school's proportion of retained students on these friendships and the moderating effect of this school characteristic on the relationship between retention and the number of same-grade friendships. Multilevel…

  5. GRADE Guidelines: 16. GRADE evidence to decision frameworks for tests in clinical practice and public health

    NARCIS (Netherlands)

    Schünemann, Holger J.; Mustafa, Reem; Brozek, Jan; Santesso, Nancy; Alonso-Coello, Pablo; Guyatt, Gordon; Scholten, Rob; Langendam, Miranda; Leeflang, Mariska M.; Akl, Elie A.; Singh, Jasvinder A.; Meerpohl, Joerg; Hultcrantz, Monica; Bossuyt, Patrick; Oxman, Andrew D.; Singh, Jasvinder; Lange, Stefan; Parmelli, Elena; Moberg, Jenny; Rosenbaum, Sarah; Brignardello-Petersen, Romina; Wiercioch, Wojtek; Davoli, Marina; Nowak, Artur; Dietl, Bart

    2016-01-01

    Objectives: To describe the grading of recommendations assessment, development and evaluation (GRADE) interactive evidence to decision (EtD) frameworks for tests and test strategies for clinical, public health, or coverage decisions. Study Design and Setting: As part of the GRADE Working Group's

  6. GRADE Guidelines : 16. GRADE evidence to decision frameworks for tests in clinical practice and public health

    NARCIS (Netherlands)

    Schünemann, Holger J.; Mustafa, Reem A.; Brozek, Jan; Santesso, Nancy; Alonso-Coello, Pablo; Guyatt, Gordon; Scholten, Rob; Langendam, Miranda W; Leeflang, Mariska; Akl, Elie A.; Singh, Jasvinder A.; Meerpohl, Joerg; Hultcrantz, Monica; Bossuyt, Patrick Mm; Oxman, Andrew D.; Schünemann, Holger J.; Mustafa, Reem A.; Brozek, Jan; Santesso, Nancy; Alonso-Coello, Pablo; Scholten, Rob; Langendam, Miranda W; Bossuyt, Patrick Mm; Leeflang, Mariska; Singh, Jasvinder; Meerpohl, Joerg; Hultcrantz, Monica; Guyatt, Gordon; Oxman, Andrew D.; Lange, Stefan; Parmelli, Elena; Moberg, Jenny; Rosenbaum, Sarah; Brignardello-Petersen, Romina; Wiercioch, Wojtek; Davoli, Marina; Nowak, Artur; Dietl, Bart

    2016-01-01

    Objectives To describe the grading of recommendations assessment, development and evaluation (GRADE) interactive evidence to decision (EtD) frameworks for tests and test strategies for clinical, public health, or coverage decisions. Study Design and Setting As part of the GRADE Working Group's

  7. [Reproducibility of Fuhrman nuclear grade: advantages of a two-grade system].

    Science.gov (United States)

    Letourneux, Hervé; Lindner, Véronique; Lang, Hervé; Massfelder, Thierry; Meyer, Nicolas; Saussine, Christian; Jacqmin, Didier

    2006-06-01

    The Fuhrman nuclear grade is the reference histoprognostic grading system routinely used all over the world for renal cell carcinoma. Studies measuring the inter-observer and intra-observer concordance of Fuhrman grade show poor results in terms of reproducibility and repeatability. These variations are due to a certain degree of subjectivity of the pathologist in application of the definition of tumour grade, particularly nuclear grade. Elements able to account for this subjectivity in renal cell carcinoma are identified from a review of the literature. To improve the reliability of nuclear grade, the territory occupied by the highest grade must be specified and the grades should probably be combined. At the present time, regrouping of grade 1 and 2 tumours as low grade and grade 3 and 4 tumours as high grade would achieve better reproducibility, while preserving the prognostic: value for overall survival. The development of new treatment modalities and their use in adjuvant situations will imply the use of reliable histoprognostic factors to specify, indications.

  8. What's in a Grade? Grading Policies and Practices in Principles of Economics

    Science.gov (United States)

    Walstad, William B.; Miller, Laurie A.

    2016-01-01

    Survey results from a national sample of economics instructors describe the grading policies and practices in principles of economics courses. The survey results provide insights about absolute and relative grading systems used by instructors, the course components and their weights that determine grades, and the type of assessment items used for…

  9. Teachers grading practices : an analysis of the reliability of teacher-assigned grade point average (GPA)

    NARCIS (Netherlands)

    van der Lans, R. M.; van de Grift, W. J. C. M.; van Veen, K.

    2015-01-01

    In previous research, teachers report that they use a hodgepodge of factors when grading students. This has led researchers to suspect that teacher-assigned grades are inflated by teacher-student interactions; the hodgepodge hypothesis. Teachers also are reported to differ in grading leniency; the

  10. Fifth Grade Elementary Students' Conceptions of Earthquakes

    Science.gov (United States)

    Savasci, Funda; Uluduz, Hatice

    2013-01-01

    This study intends to investigate the fifth grade students' conceptions of earthquakes. Twenty two grade 5 students (11-12 years old) from five different elementary schools in Istanbul voluntarily participated in the study. Data were collected from semi-structured interviews with each participant. Six interview questions were designed by…

  11. The Psychology of Grading Skill Learning.

    Science.gov (United States)

    Freeman, Caryl

    Many teachers use grades as a weapon or a defense--not as the powerful learning tool they can be. A grading system in which students write papers over and over until they are fully acceptable, and in which they earn checkmarks for each piece of work accepted, serves as a powerful motivator. The checkmark system adheres to six primary learning…

  12. Chemistry, Grade 13. Curriculum S-17E.

    Science.gov (United States)

    Ontario Dept. of Education, Toronto.

    GRADES OR AGES: Grade 13. SUBJECT MATTER: Chemistry. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into 15 units, each of which is in list form. It is offset printed and staple-bound with a paper cover. OBJECTIVES AND ACTIVITIES: No objectives are mentioned. Topics to be covered are listed in each unit. Most units also list several…

  13. What's ahead in automated lumber grading

    Science.gov (United States)

    D. Earl Kline; Richard Conners; Philip A. Araman

    1998-01-01

    This paper discusses how present scanning technologies are being applied to automatic lumber grading. The presentation focuses on 1) what sensing and scanning devices are needed to measure information for accurate grading feature detection, 2) the hardware and software needed to efficiently process this information, and 3) specific issues related to softwood lumber...

  14. 7 CFR 29.6028 - No Grade.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false No Grade. 29.6028 Section 29.6028 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6028 No Grade. A designation applied to a lot of tobacco classified as...

  15. Learning with Text in the Primary Grades.

    Science.gov (United States)

    Guillaume, Andrea M.

    1998-01-01

    Provides a rationale for learning-with-text experiences for primary-grade children; lists 10 general approaches to foster primary-grade content area reading; and offers a sample lesson incorporating these approaches that promotes comprehension of text and content matter. Suggests that trade books, textbooks, realistic fiction, and other print…

  16. Ninth Grade Student Attendance: Teacher Perceptional Study

    Science.gov (United States)

    Caldwell, Barbara A.

    2010-01-01

    Excessive student absenteeism among ninth graders was a major problem within a metropolitan Georgia high school. In order to solve the attendance problem and several other academic concerns, the school administration implemented a smaller learning community for ninth grade students. The Ninth Grade Academy concept implemented at the beginning of…

  17. Successful Transitions: The Sheyenne Ninth Grade Academy

    Science.gov (United States)

    Hall, Brenda S.; Holland, Carol E. Buchholz; Karsh, Lisa; Wang, Ting

    2011-01-01

    In this article, we share outcomes from the implementation of a ninth-grade academy in a large, comprehensive, Northern Plains, United States, school district. The article discusses the effectiveness of this reform in terms of the academic and social preparedness for students during the ninth-grade year and transition to high school. Findings…

  18. Consumer Preference for Graded Maple Syrup

    Science.gov (United States)

    Paul E. Sendak

    1978-01-01

    The three grades of maple syrup and a commercial table syrup containing artificial flavor and 3 percent pure maple syrup were evaluated by 1,018 women in four cities. The results indicate that differences in preference for flavor are related to how close the respondents are to a maple syrup-production region. Differences in preference among grades of pure maple syrup...

  19. Contraction of graded su(2) algebra

    International Nuclear Information System (INIS)

    Patra, M.K.; Tripathy, K.C.

    1989-01-01

    The Inoenu-Wigner contraction scheme is extended to Lie superalgebras. The structure and representations of extended BRS algebra are obtained from contraction of the graded su(2) algebra. From cohomological consideration, we demonstrate that the graded su(2) algebra is the only superalgebra which, on contraction, yields the full BRS algebra. (orig.)

  20. Guiding Readers in the Middle Grades

    Science.gov (United States)

    Morgan, Denise N.; Williams, Jeffrey L.; Clark, Barbara; Hatteberg, Scott; Hauptman, Gayle Marek; Kozel, Claudia; Paris, Joe

    2013-01-01

    Guided reading is an instructional practice commonly used in primary and intermediate grades (Ford & Opitz, 2008; Fountas & Pinnell, 2001). It is used less in middle grades settings (Allen, 2000) where "one size-fits-all instruction" prevails (Allington, 2012). While teachers can read about the principles of guided reading in…

  1. Perceptions of restaurateurs on quality grading

    Directory of Open Access Journals (Sweden)

    Joseph Roberson

    2014-01-01

    Full Text Available A restaurateur's strategic focus is to maximise wealth for the owner(s. To achieve wealth maximisation, a restaurateur could implement one or more of the following strategies: focus strategy, cost-leadership strategy and/or differentiation strategy. A management intervention a restaurateur could implement to achieve this is quality differentiation. Grading of an establishment will assist a restaurateur in becoming a market leader. Currently there no national restaurant grading system exists in South Africa. As support and participation of restaurateurs in any future quality grading system are essential, it is imperative to test their perceptions of the implementation of a quality grading scale. The aim of this paper is to gather the perceptions of restaurateurs of an envisaged scale that could be used to grade independent full-service restaurants. In this study the researcher tested the perceptions of restaurateurs using nine possible outcomes of implementing quality grading in the independent fullservice restaurant segment. The outcomes to be tested were presented to restaurateurs in a questionnaire uploaded on "survey monkey". This was emailed to 3 286 restaurateurs and 265 responses were received. Respondents who were positive regarding grading indicated that they were enthusiastic about the impact grading would have on international tourism, as well as the fact that it could contribute to an increase in the value of their establishments.

  2. Does Grading Encourage Participation? Evidence & Implications

    Science.gov (United States)

    Paff, Lolita A.

    2015-01-01

    Research on the effects of grading on participation behavior is mixed. This study adds to the literature by analyzing the motivational effects of a policy that incorporates student self-assessment, flexible course weighting of the participation grade, and an expanded definition of participation. The results suggest that in some classes, more than…

  3. Determinants of College Grade Point Averages

    Science.gov (United States)

    Bailey, Paul Dean

    2012-01-01

    Chapter 2: The Role of Class Difficulty in College Grade Point Averages. Grade Point Averages (GPAs) are widely used as a measure of college students' ability. Low GPAs can remove a students from eligibility for scholarships, and even continued enrollment at a university. However, GPAs are determined not only by student ability but also by the…

  4. Bruxism defined and graded: an international consensus

    NARCIS (Netherlands)

    Lobbezoo, F.; Ahlberg, J.; Glaros, A.G.; Kato, T.; Koyano, K.; Lavigne, G.J.; de Leeuw, R.; Manfredini, D.; Svensson, P.; Winocur, E.

    2013-01-01

    To date, there is no consensus about the definition and diagnostic grading of bruxism. A written consensus discussion was held among an international group of bruxism experts as to formulate a definition of bruxism and to suggest a grading system for its operationalisation. The expert group defined

  5. Functionally graded Ti6Al4V and Inconel 625 by Laser Metal Deposition

    Science.gov (United States)

    Pulugurtha, Syamala R.

    The objective of the current work was to fabricate a crack-free functionally graded Ti6Al4V and Inconel 625 thin wall structure by Laser Metal Deposition (LMD). One potential application for the current material system is the ability to fabricate a functionally graded alloy that can be used in a space heat exchanger. The two alloys, Inconel 625 and Ti6Al4V are currently used for aerospace applications. They were chosen as candidates for grading because functionally grading those combines the properties of high strength/weight ratio of Ti6Al4V and high temperature oxidation resistance of Inconel 625 into one multifunctional material for the end application. However, there were challenges associated with the presence of Ni-Ti intermetallic phases (IMPs). The study focused on several critical areas such as (1) understanding microstructural evolution, (2) reducing macroscopic cracking, and (3) reducing mixing between graded layers. Finite element analysis (FEA) was performed to understand the effect of process conditions on multilayer claddings for simplified material systems such as SS316L and Inconel 625 where complex microstructures did not form. The thermo-mechanical models were developed using Abaqus(TM) (and some of them experimentally verified) to predict temperature-gradients; remelt layer depths and residual stresses. Microstructure evolution along the functionally graded Ti6Al4V and Inconel 625 was studied under different processing and grading conditions. Thermodynamic modeling using Factsage (v 6.1) was used to construct phase diagrams and predict the possible equilibrium major/minor phases (verified experimentally by XRD) that may be present along the functionally graded Ti6Al4V and Inconel 625 thin wall structures.

  6. Foraminal syringomyelia: suggestion for a grading system.

    Science.gov (United States)

    Versari, P P; D'Aliberti, G; Talamonti, G; Collice, M

    1993-01-01

    The standard treatment of foraminal syringomyelia includes foramen magnum decompression and duraplasty. Improvement or stabilization of the disease are achieved in most of cases. However, at least one third of patients are reported to receive little or no benefit. In this paper we retrospectively reviewed a series of 40 consecutive foramen magnum decompressions in order to identify the possible pre-operative outcome predictors. Based on clinical evolution, neurological impairment and radiological features, a scale of severity was fixed and retrospectively tested. A pre-operative score was obtained for each patient and was correlated with the surgical results. Then a four level grading system was derived. All grade I and grade II patients achieved good results (improvement or stabilization), whereas grade III patients showed intermediate behaviour and grade IV invariably worsened. On this basis, surgical results of foramen magnum decompression might be further improved provided that a careful pre-operative selection is made.

  7. Uso da grade aradora superpesada, pesada e arado de discos na incorporação de calcário em profundidade e na produção de milho Use of the super heavy and heavy harrow and disk plow in limestone material incorporation in corn crop

    Directory of Open Access Journals (Sweden)

    Renato de M. Prado

    2004-04-01

    Full Text Available Este trabalho teve o objetivo de avaliar o efeito dos modos de incorporação de calcário na correção da acidez no perfil do solo e na produção do milho. Para tanto, foi conduzido um experimento em Latossolo Vermelho Distrófico, textura argilosa, em Uberlândia - MG, no período de maio de 1995 a março de 1997. O delineamento experimental foi em esquema de parcelas subdivididas. As parcelas principais foram constituídas pelos modos de incorporação do calcário: grade aradora pesada (14 discos de 0,86 m e grade niveladora (60 discos de 0,56 m; arado de disco (4 discos de 0,66 m e grade niveladora; grade aradora superpesada (14 discos de 0,86 m e grade niveladora; as subparcelas foram as doses de calcário dolomítico: 0; 6 e 9,2 t ha-1. O modo de incorporação do calcário afetou a eficiência da calagem no perfil do solo. A gradagem pesada não foi adequada para a incorporação do calcário. A aração com arado de disco mais gradagem niveladora teve desempenho satisfatório, atingindo até 0,20 m de profundidade. A gradagem com grade aradora superpesada proporcionou maior uniformidade e profundidade de incorporação, com neutralização da acidez do solo até 0,30 m de profundidade. O milho respondeu linearmente à aplicação do calcário, e o modo alternativo de incorporação pela gradagem com grade superpesada proporcionou maior produção.The objective of the present study was to assess the effect of the modes of lime incorporation on the correction of soil acidity and on corn production. An experiment was conducted on Typic Hapludox of clay texture in Uberlândia - MG, Brazil, from May 1995 to March 1997. The experimental design consisted of a split-plot scheme. The main plots consisted of the modes of lime incorporation: heavy harrow (14 disks of 0.86 m and leveling harrow (60 disks of 0.56 m; disk plow (4 disks of 0.66 m and a leveling harrow; super heavy harrow (14 disks of 0.86 m and a leveling harrow. The subplots were

  8. Mechanical Material

    International Nuclear Information System (INIS)

    Kim, Gap Yong; Jang, Gun Ik; Kim, Dung Jung; Kim, Ui Do

    1999-02-01

    This book introduces characteristics of metal with crystal structure and plastic deformation of metal, equilibrium diagram of alloy, steel such as constitutional diagram and structure of carbon steel, and heat treatment of steel, structural alloy steel, tool material, corrosion and anticorrosion of steel and stainless steel, heat resisting material and properties of steel against high temperature, strengthening of surface of steel, cast iron, nonferrous metal material and materials test.

  9. Magnetic Materials

    Science.gov (United States)

    Spaldin, Nicola A.

    2003-04-01

    Magnetic materials are the foundation of multi-billion dollar industries and the focus of intensive research across many disciplines. This book covers the fundamentals, basic theories and applications of magnetism and conventional magnetic materials. Based on a lecture course given by Nicola Spaldin in the Materials Department at University of California, Santa Barbara, the book is ideal for a one- semester course in magnetic materials. It contains numerous homework problems and solutions.

  10. Readability of pediatric health materials for preventive dental care

    Directory of Open Access Journals (Sweden)

    Riedy Christine A

    2006-11-01

    Full Text Available Abstract Background This study examined the content and general readability of pediatric oral health education materials for parents of young children. Methods Twenty-seven pediatric oral health pamphlets or brochures from commercial, government, industry, and private nonprofit sources were analyzed for general readability ("usability" according to several parameters: readability, (Flesch-Kincaid grade level, Flesch Reading Ease, and SMOG grade level; thoroughness, (inclusion of topics important to young childrens' oral health; textual framework (frequency of complex phrases, use of pictures, diagrams, and bulleted text within materials; and terminology (frequency of difficult words and dental jargon. Results Readability of the written texts ranged from 2nd to 9th grade. The average Flesch-Kincaid grade level for government publications was equivalent to a grade 4 reading level (4.73, range, 2.4 – 6.6; F-K grade levels for commercial publications averaged 8.1 (range, 6.9 – 8.9; and industry published materials read at an average Flesch-Kincaid grade level of 7.4 (range, 4.7 – 9.3. SMOG readability analysis, based on a count of polysyllabic words, consistently rated materials 2 to 3 grade levels higher than did the Flesch-Kincaid analysis. Government sources were significantly lower compared to commercial and industry sources for Flesch-Kincaid grade level and SMOG readability analysis. Content analysis found materials from commercial and industry sources more complex than government-sponsored publications, whereas commercial sources were more thorough in coverage of pediatric oral health topics. Different materials frequently contained conflicting information. Conclusion Pediatric oral health care materials are readily available, yet their quality and readability vary widely. In general, government publications are more readable than their commercial and industry counterparts. The criteria for usability and results of the analyses

  11. Material Programming

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Boer, Laurens; Tsaknaki, Vasiliki

    2017-01-01

    In the near future every other smart material will have computational power embedded in the form of graphene transistors or nanotubes. These will be the ultimate computational composites: materials that hold classic material qualities, such as structural durability, flexibility, texture, weight, ...

  12. Selective Oxidation of Soft Grade Carbon

    Directory of Open Access Journals (Sweden)

    Zecevic, N.

    2007-12-01

    Full Text Available Oil-furnace carbon black is produced by pyrolysis of gaseous or liquid hydrocarbons or their mixtures. The oil feedstock for the production of oil-furnace carbon black is mainly composed of high-boiling aromatic hydrocarbons, which are residues of petroleum cracking, while the gaseous raw material is commonly natural gas. Most of the oil-furnace carbon black production (> 99 % is used as a reinforcing agent in rubber compounds. Occasionally, oil-furnace carbon blacks are used in contact with other rubber compounds and fillers that have different pigments, particularly with the color white. It has been observed that frequently a migrating rubber soluble colorant would enter the white or light colored rubber composition from the adjacent carbon black filled rubber, resulting in a highly undesirable staining effect. Methods for determining non-oxidized residue on the surface of the oil-furnace carbon black include extraction of carbon black with the appropriate organic solvent, and measuring the color of the organic solvent by means of a colorimeter on 425 nm (ASTM D 1618-99. Transmittance values of 85 % or more are indicative of a practically non-staining carbon black, while transmittance values below 50 % generally lead to a carbon black with pronounced staining characteristics. Many oil-furnace carbon blacks, particularly those with a larger particle size (dp > 50 nm which are produced by pyrolysis, have strongly adsorbed non-reacted oil on their surfaces. Upon incorporation in a rubber compound, the colored materials are gradually dissolved by the rubber matrix and migrate freely into adjacent light colored rubber compounds, causing a highly objectionable staining effect. Adjusting furnace parameters in the industrial process of producing specific soft grades of carbon black cannot obtain minimal values of toluene discoloration. The minimal value of toluene discoloration is very important in special applications. Therefore, after-treatment of

  13. Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Discrete functionally graded composites are the novel composites which have high potential in the brake friction material applications. In this paper, we have prepared discrete functional graded Cu/10%SiC/20%graphite(Gr)/10%boron nitride (h-BN) hybrid composites by the layer stacking compaction and pressure sintering ...

  14. Electrically active defects in solar grade multicrystalline silicon

    DEFF Research Database (Denmark)

    Dahl, Espen

    2013-01-01

    Shortage in high purity silicon feedstock, as a result of the formidable increased demand for solar cell devices during the last two decades, can be mitigated by the introduction of cheaper feedstock of solar grade (So-G) quality. Silicon produced through the metallurgical process route has shown...... the potential to be such a feedstock. However, this feedstock has only few years of active commercial history and the detailed understanding of the nature of structural defects in this material still has fundamental shortcomings. In this thesis the electrical activity of structural defects, commonly associated...

  15. Stochastic Investigation of Natural Frequency for Functionally Graded Plates

    Science.gov (United States)

    Karsh, P. K.; Mukhopadhyay, T.; Dey, S.

    2018-03-01

    This paper presents the stochastic natural frequency analysis of functionally graded plates by applying artificial neural network (ANN) approach. Latin hypercube sampling is utilised to train the ANN model. The proposed algorithm for stochastic natural frequency analysis of FGM plates is validated and verified with original finite element method and Monte Carlo simulation (MCS). The combined stochastic variation of input parameters such as, elastic modulus, shear modulus, Poisson ratio, and mass density are considered. Power law is applied to distribute the material properties across the thickness. The present ANN model reduces the sample size and computationally found efficient as compared to conventional Monte Carlo simulation.

  16. Composite Materials

    DEFF Research Database (Denmark)

    Nielsen, Lauge Fuglsang

    This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. "Composite Materials" provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the significance of phase geometry....... The book enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties. A number of examples are presented: Special composite properties considered are stiffness, shrinkage, hygro-thermal behavior...... materials. Numerical procedures are outlined which facilitate the practical analysis of any feature considered in this book. Examples are presented which illustrate the analysis of well-known materials such as concrete, hardening cement paste, ceramics, tile, wood, impregnated and reinforced materials...

  17. Aerospace materials and material technologies

    CERN Document Server

    Wanhill, R

    2017-01-01

    This book is a comprehensive compilation of chapters on materials (both established and evolving) and material technologies that are important for aerospace systems. It considers aerospace materials in three Parts. Part I covers Metallic Materials (Mg, Al, Al-Li, Ti, aero steels, Ni, intermetallics, bronzes and Nb alloys); Part II deals with Composites (GLARE, PMCs, CMCs and Carbon based CMCs); and Part III considers Special Materials. This compilation has ensured that no important aerospace material system is ignored. Emphasis is laid in each chapter on the underlying scientific principles as well as basic and fundamental mechanisms leading to processing, characterization, property evaluation and applications. A considerable amount of materials data is compiled and presented in appendices at the end of the book. This book will be useful to students, researchers and professionals working in the domain of aerospace materials.

  18. [Formation and evolution of commodity specification and grade of traditional Chinese medicine].

    Science.gov (United States)

    Li, Peng-Ying; Wang, Hai-Yang; Li, Jian; Zhan, Zhi-Lai; Yang, Guang

    2016-03-01

    As an important reference index to evaluate the quality of Chinese medicinal materials, the commodity specification and grade of traditional Chinese medicine has an effect on the medicinal material's price, can promote "high quality and high price" of the traditional Chinese medicine, prompt market transactions more convenient and standard, and has a great significance to the development of the whole traditional Chinese medicine industry. The formation of traditional Chinese medicine specifications and grades experienced a long historical development process. In order to provide the reference for modification of the product specifications and grades standards and management of traditional Chinese medicine products, the author consulted a large number of materia medica books and related references, sorted and analyzed the historical development process. The author divided the formation and development process into four stages, including germination stage before the Southern and Northern Dynasties, development stage of Tang and Song Dynasty, mature period of the Ming and Qing Dynasties and the inheritance development stage since the foundation of the People's Republic. The author believes that the clinical curative effect is the driving force to promote the development of commodity specifications and grades. In addition, the national pharmaceutical policy, international status, the level of science and technology also influence the development of commodity specifications and grades in some extents. Finally, the author provides three piece of suggestions for the modification of the product specifications and grades standards, according to the historical development rule. Copyright© by the Chinese Pharmaceutical Association.

  19. Readability of Online Materials for Rhinoplasty.

    Science.gov (United States)

    Santos, Pauline Joy F; Daar, David A; Paydar, Keyianoosh Z; Wirth, Garrett A

    2018-01-01

    Rhinoplasty is a popular aesthetic and reconstructive surgical procedure. However, little is known about the content and readability of online materials for patient education. The recommended grade level for educational materials is 7th to 8th grade according to the National Institutes of Health (NIH). This study aims to assess the readability of online patient resources for rhinoplasty. The largest public search engine, Google, was queried using the term "rhinoplasty" on February 26, 2016. Location filters were disabled and sponsored results excluded to avoid any inadvertent search bias. The 10 most popular websites were identified and all relevant, patient-directed information within one click from the original site was downloaded and saved as plain text. Readability was analyzed using five established analyses (Readability-score.com, Added Bytes, Ltd., Sussex, UK). Analysis of ten websites demonstrates an average grade level of at least 12 th grade. No material was at the recommended 7 th to 8 th grade reading level (Flesch-Kincaid, 11.1; Gunning-Fog, 14.1; Coleman-Liau, 14.5; SMOG 10.4; Automated Readability, 10.7; Average Grade Level, 12.2). Overall Flesch-Kincaid Reading Ease Index was 43.5, which is rated as "difficult." Online materials available for rhinoplasty exceed NIH-recommended reading levels, which may prevent appropriate decision-making in patients considering these types of surgery. Outcomes of this study identify that Plastic Surgeons should be cognizant of available online patient materials and make efforts to develop and provide more appropriate materials. Readability results can also contribute to marketing strategy and attracting a more widespread interest in the procedure.

  20. Comparative thermal buckling analysis of functionally graded plate

    Directory of Open Access Journals (Sweden)

    Čukanović Dragan V.

    2017-01-01

    Full Text Available A thermal buckling analysis of functionally graded thick rectangular plates accord¬ing to von Karman non-linear theory is presented. The material properties of the functionally graded plate, except for the Poisson’s ratio, were assumed to be graded in the thickness direction, according to a power-law distribution, in terms of the volume fractions of the metal and ceramic constituents. Formulations of equilibrium and stability equations are derived using the high order shear deformation theory based on different types of shape functions. Analytical method for determination of the critical buckling temperature for uniform increase of temperature, linear and non-linear change of temperature across thickness of a plate is developed. Numeri¬cal results were obtained in МATLAB software using combinations of symbolic and numeric values. The paper presents comparative results of critical buckling tempera¬ture for different types of shape functions. The accuracy of the formulation presented is verified by comparing to results available from the literature.

  1. Machine vision for timber grading singularities detection and applications

    Science.gov (United States)

    Hittawe, Mohamad Mazen; Sidibé, Désiré; Beya, Ouadi; Mériaudeau, Fabrice

    2017-11-01

    This article deals with machine vision techniques applied to timber grading singularities. Timber used for architectural purposes must satisfy certain mechanical requirements, and, therefore, must be mechanically graded to ensure the manufacturer that the product complies with the requirements. However, the timber material has many singularities, such as knots, cracks, and presence of juvenile wood, which influence its mechanical behavior. Thus, identifying those singularities is of great importance. We address the problem of timber defects segmentation and classification and propose a method to detect timber defects such as cracks and knots using a bag-of-words approach. Extensive experimental results show that the proposed methods are efficient and can improve grading machines performances. We also propose an automated method for the detection of transverse knots, which allows the computation of knot depth ratio (KDR) images. Finally, we propose a method for the detection of juvenile wood regions based on tree rings detection and the estimation of the tree's pith. The experimental results show that the proposed methods achieve excellent results for knots detection, with a recall of 0.94 and 0.95 on two datasets, as well as for KDR image computation and juvenile timber detection.

  2. GRADE INFLATION: An Issue for Higher Education?

    Directory of Open Access Journals (Sweden)

    Donald L. CARUTH,

    2013-01-01

    Full Text Available Grade inflation impacts university credibility, student courses of study, choices of institution, and other areas. There has been an upward shift in grades without a corresponding upward shift in knowledge gained. Some of the most frequently mentioned causes of grade inflation are: Ø student evaluations of professors, Ø student teacher dynamics, Ø merit-based financial aid, and Ø student expectations. Ø Among the reasons for higher student grades on the part of professors are: Ø fear of student evaluations, Ø avoidance of bad relations with students, Ø below average teaching skills,Ø lack of experience, Ø a lack of clearly stated objectives, and Ø job security. While grades are not a perfect answer to assessing student performance in a course they are still the best answer we have for evaluating students. In order to evaluate students more accurately, universities must identify the problems in grading and grading practices. Once this is accomplished new practices can be designed and policies implemented.

  3. Making the GRADE: CHEST Updates Its Methodology.

    Science.gov (United States)

    Diekemper, Rebecca L; Patel, Sheena; Mette, Stephen A; Ornelas, Joseph; Ouellette, Daniel R; Casey, Kenneth R

    2018-03-01

    The American College of Chest Physicians (CHEST) has been at the forefront of evidence-based clinical practice guideline development for more than 2 decades. In 2006, CHEST adopted a modified system of Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to support their rigorous guideline development methodology. The evolution of CHEST's Living Guidelines Model, as well as their collaborative efforts with other organizations, has necessitated improvements in their guideline development methodology. CHEST has made the decision to transition to the standard GRADE method for rating the certainty of evidence and grading recommendations in their evidence-based clinical practice guidelines, a deviation from the modified approach that was adopted in 2006. The standard GRADE approach will be used to grade recommendations in all CHEST guidelines, including updates to previously published guidelines. CHEST's adoption of a standard GRADE approach will ensure that its guideline development methodology is more consistent with that used by other organizations, will better align evidence synthesis methods, and will result in more explicit and easy to understand recommendations. Copyright © 2016 American College of Chest Physicians. All rights reserved.

  4. Grades and Ranking: When Tenure Affects Assessment

    Directory of Open Access Journals (Sweden)

    Jean Filetti

    2010-10-01

    Full Text Available This article examines how a faculty member's status-'either tenured or tenure-track-'might affect the grades assigned to students in a writing class. We begin with a brief review of the research surrounding faculty to student assessment practices and follow with specific controversies regarding faculty motivation pertaining to grading practices. We interpret the grade distributions of tenured and tenure-track faculty members teaching a sophomore-level writing course in an English Department at a small, public liberal arts university in Virginia, examine the relationship between grade distributions and faculty rank, and conclude that tenure-track faculty grade more leniently than their tenured colleagues, primarily in the number of - A- grades assigned. The results of this study suggest that tenured professors tend to award fewer - As- than tenure-track professors. We posit that at universities where emphasis is placed upon teaching, two specific patterns emerge: reciprocity may be an unspoken agreement between some faculty and students with regard to the exchange of good grades for good evaluations, or with experience comes rigor.

  5. Assessment of Lean Grade Duplex Stainless Steels for Nuclear Power Applications

    Science.gov (United States)

    Young, George A.; Tucker, Julie D.; Lewis, Nathan; Plesko, Eric; Sander, Paul

    This research assesses the thermal stability of lean grades of duplex stainless steel relative to standard grade alloys. Both hot rolled plate and gas-tungsten-arc weld deposits of selected alloys were isothermally aged in the temperature regime of α-α' phase separation (T = 800°F / 427°C) for times up to 1,000 hours. The degree of embrittlement was assessed via changes in hardness and Charpy impact energy. Additionally, the materials were characterized by light optical microscopy, electron microprobe analysis (EMPA), analytical electron microscopy (AEM), and x-ray diffraction (XRD) to better understand the factors that affect embrittlement. Impact testing shows that at equivalent thermal exposure, small changes in alloy composition have a significant effect on the degree of embrittlement. Microscopy reveals that spinodal decomposition of the ferrite occurs in all the alloys tested at 800°F (427°C). Additionally, transmission electron microscopy shows complex intermetallic formation, likely G phase, in the standard grade weld metal. Relative to their standard grade counterparts, both the lean grade plate and the lean grade weld deposit display 10X slower embrittlement kinetics for the conditions studied. Despite the relatively complex metallurgy of these alloys, this research indicates that lean grade duplex stainless steels could have broad applicability to lower temperature components in nuclear power systems.

  6. 7 CFR 28.451 - Below Color Grade Cotton.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Below Color Grade Cotton. 28.451 Section 28.451... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Color Grade Cotton § 28.451 Below Color Grade Cotton. Below color grade cotton is American Upland cotton which is lower in color grade than Good...

  7. 7 CFR 28.471 - Below Leaf Grade Cotton.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Below Leaf Grade Cotton. 28.471 Section 28.471... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Below Leaf Grade Cotton § 28.471 Below Leaf Grade Cotton. Below leaf grade cotton is American Upland cotton which is lower in leaf grade than Leaf...

  8. Does Relative Grading help Male Students?

    DEFF Research Database (Denmark)

    Czibor, Eszter; Onderstal, Sander; Sloof, Randolph

    for male students than absolute grading. In the full sample, we find weak support for our hypothesis. Among the more motivated students we find evidence that men indeed score significantly higher on the test when graded on a curve. Female students, irrespective of their motivation, do not increase......The provision of non-pecuniary incentives in education is a topic that has received much scholarly attention lately. Our paper contributes to this discussion by investigating the effectiveness of grade incentives in increasing student performance. We perform a direct comparison of the two most...

  9. Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

    Directory of Open Access Journals (Sweden)

    Muljani Srie

    2016-01-01

    Full Text Available Potassium silicate fertilizer grade were successfully produced by direct fusion of silica (SiO2 and potasium (KOH and K2CO3 in furnaces at temperatures up to melting point of mixture. The geothermal sludge (98% SiO2 and the pyrophyllite (95% SiO2 were used as silica sources. The purposes of the study was to synthesise potassium silicate fertilizer grade having solids concentrations in the range of 31-37% K2O, and silica in the range of 48-54% SiO2. The weight ratio of silicon dioxide/potasium solid being 1:1 to 5:1. Silica from geothermal sludge is amorphous, whereas pyrophylite is crystalline phase. The results showed that the amount of raw materials needed to get the appropriate molar ratio of potassium silicate fertilizer grade are different, as well as the fusion temperature of the furnace. Potassium silicate prepared from potassium hydroxide and geothermal sludge produced a low molar ratio (2.5: 1 to 3: 1. The potassium required quite small (4:1 in weight ratio, and on a fusion temperature of about 900 °C. Meanwhile, the potassium silicate prepared from pyrophyllite produced a high molar ratio (1.4 - 9.4 and on a fusion temperature of about 1350 °C, so that potassium needed large enough to meet the required molar ratio for the fertilizer grade. The product potassium silicate solid is amorphous with a little trace of crystalline.

  10. Design and evaluation of foamed asphalt base materials : [research summary].

    Science.gov (United States)

    2013-05-01

    Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), : recycled concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt : binder to produce a partially stabilized base material. Although widely used, most :...

  11. Design and evaluation of foamed asphalt base materials.

    Science.gov (United States)

    2013-05-01

    Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP), recycled : concrete (RC), and/or graded aggregate base (GAB) with a foamed asphalt binder to produce a : partially stabilized base material. The objectives of this study...

  12. Non-invasive tryptophan fluorescence measurements as a novel method of grading cataract.

    Science.gov (United States)

    Erichsen, Jesper Høiberg; Mensah, Aurore; Kessel, Line

    2017-12-01

    Development of non-invasive treatments for cataract calls for a sensitive diagnostic assay. We conducted a study to test whether the ratio of folded tryptophan to non-tryptophan fluorescence emission (F-factor) may be used for grading cataracts in human lenses. The F-factor was measured on aspirated lens material from eyes undergoing femtosecond laser assisted cataract surgery (FLACS) and was compared to a preoperative optical grading of cataract using Scheimpflug imaging. The preoperative optical grading allocated the cataracts to 1 of 4 categories according to the density of the cataract. All cataracts were age-related. Lens material from 16 eyes of 14 patients was included in the study. Cataracts were preoperatively graded in categories 1, 2 and 3. No lenses were category 4. For nuclear cataracts mean values of F-factor were 52.9 (SD 12.2), 61.7 (SD 5.3) and 75.7 (SD 8.9) for categories 1, 2 and 3 respectively. Linear regression on F-factor as a function of preoperative grading category showed increasing values of F-factor with increasing preoperative grading category, R 2  = 0.515. Our experiment showed that preoperative optical grading of cataracts by Scheimpflug imaging may correlate to measures of tryptophan and non-tryptophan fluorescence in human lenses. Based on our results we find that measuring the ratio between tryptophan- and non-tryptophan fluorescence may be a future tool for grading cataracts, but further research is needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Nano Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jin, In Ju; Lee, Ik Mo; Kwon, Yeung Gu; and others

    2006-02-15

    This book introduces background of nano science such as summary, plenty room at the bottom, access way to nano technique, nanoparticles using bottom-up method which are a marvel of nature, and modern alchemy : chemical synthesis of artificial nano structure, understanding of quantum mechanics, STM/AFM, nano metal powder, ceramic nanoparticles, nano structure film, manufacture of nanoparticles using reverse micelle method, carbon nano tube, sol-gel material, nano energy material, nano catalyst nano bio material technology and spintronics.

  14. Nano Materials

    International Nuclear Information System (INIS)

    Jin, In Ju; Lee, Ik Mo; Kwon, Yeung Gu

    2006-02-01

    This book introduces background of nano science such as summary, plenty room at the bottom, access way to nano technique, nanoparticles using bottom-up method which are a marvel of nature, and modern alchemy : chemical synthesis of artificial nano structure, understanding of quantum mechanics, STM/AFM, nano metal powder, ceramic nanoparticles, nano structure film, manufacture of nanoparticles using reverse micelle method, carbon nano tube, sol-gel material, nano energy material, nano catalyst nano bio material technology and spintronics.

  15. Material Systems

    DEFF Research Database (Denmark)

    Jensen, Mads Brath; Mortensen, Henrik Rubæk; Mullins, Michael

    2009-01-01

    This paper describes and reflects upon the results of an investigative project which explores the setting up of a material system - a parametric and generative assembly consisting of and taking into consideration material properties, manufacturing constraints and geometric behavior. The project...... approaches the subject through the construction of a logic-driven system aiming to explore the possibilities of a material system that fulfills spatial, structural and performative requirements concurrently and how these are negotiated in situations where they might be conflicting....

  16. Material focus

    DEFF Research Database (Denmark)

    Sokoler, Tomas; Vallgårda, Anna K. A.

    2009-01-01

    In this paper we build on the notion of computational composites, which hold a material perspective on computational technology. We argue that a focus on the material aspects of the technology could be a fruitful approach to achieve new expressions and to gain a new view on the technology's role...... in design. We study two of the computer's material properties: computed causality and connectability and through developing two computational composites that utilize these properties we begin to explore their potential expressions....

  17. Transition from low-grade endometrial stromal sarcoma to high-grade endometrial stromal sarcoma.

    Science.gov (United States)

    Ohta, Yoshiki; Suzuki, Takao; Omatsu, Mutsuko; Hamatani, Shigeharu; Shiokawa, Akira; Kushima, Miki; Ota, Hidekazu

    2010-07-01

    We report on a case of a primary low-grade endometrial stromal sarcoma (ESS) that progressed to a secondary high-grade ESS. In the secondary tumor, the immunohistochemical profile and focal tumor cell proliferation pattern suggested that this tumor was not truly undifferentiated, but possessed features of endometrial stroma. Low-grade ESS of our patient's primary tumor showed p53 protein overexpression, which is unusual in low-grade ESS, and her secondary high-grade ESS showed more prominent p53 immunoreactivity. This indicates that low-grade ESS that shows p53 immunoreactivity might progress to high-grade ESS, and it is considered that such cases of low-grade ESS should pay attention to the prognosis. Immunoreactivity for epidermal growth factor receptor was observed in both tumors, suggesting a relationship between the primary and secondary tumors in our case. Further study requires more immunohistochemical data for cases in which low-grade ESS transitions to high-grade ESS; in particular, data on epidermal growth factor receptor expression are necessary to define new therapeutic strategies for ESS.

  18. MATERIAL CONTROL ACCOUNTING INMM

    Energy Technology Data Exchange (ETDEWEB)

    Hasty, T.

    2009-06-14

    Since 1996, the Mining and Chemical Combine (MCC - formerly known as K-26), and the United States Department of Energy (DOE) have been cooperating under the cooperative Nuclear Material Protection, Control and Accounting (MPC&A) Program between the Russian Federation and the U.S. Governments. Since MCC continues to operate a reactor for steam and electricity production for the site and city of Zheleznogorsk which results in production of the weapons grade plutonium, one of the goals of the MPC&A program is to support implementation of an expanded comprehensive nuclear material control and accounting (MC&A) program. To date MCC has completed upgrades identified in the initial gap analysis and documented in the site MC&A Plan and is implementing additional upgrades identified during an update to the gap analysis. The scope of these upgrades includes implementation of MCC organization structure relating to MC&A, establishing material balance area structure for special nuclear materials (SNM) storage and bulk processing areas, and material control functions including SNM portal monitors at target locations. Material accounting function upgrades include enhancements in the conduct of physical inventories, limit of error inventory difference procedure enhancements, implementation of basic computerized accounting system for four SNM storage areas, implementation of measurement equipment for improved accountability reporting, and both new and revised site-level MC&A procedures. This paper will discuss the implementation of MC&A upgrades at MCC based on the requirements established in the comprehensive MC&A plan developed by the Mining and Chemical Combine as part of the MPC&A Program.

  19. Hunger: The World Food Crisis. An NSTA Environmental Materials Guide.

    Science.gov (United States)

    Fowler, Kathryn Mervine

    This document provides a materials guide containing annotated bibliographies of literature for teachers and students, a film guide, and a curriculum materials guide for educational sources relating to hunger, food, and the world food crisis. Materials span the range from pre-school to grade 12. (SL)

  20. Materials characterisation

    International Nuclear Information System (INIS)

    Azali Muhammad

    2005-01-01

    Various nuclear techniques have been developed and employed by technologies and scientists worldwide to physically and chemically characterise the material particularly those that have applications in industry. These include small angle neutron scattering (SANS), x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) for the internal structural study of material, whereas, the x-ray fluorescence (XRF) for the chemical analysis, while the Moessbauer spectroscopy for the study on the magnetic properties and structural identity of material. Basic principle and instrumentations of the techniques are discussed in this chapter. Example of their applications in various disciplines particularly in characterisation of industrial materials also described