An accurate higher order displacement model with shear and normal deformations effects for functionally graded plates

International Nuclear Information System (INIS)

Jha, D.K.; Kant, Tarun; Srinivas, K.; Singh, R.K.

2013-01-01

Highlights: • We model through-thickness variation of material properties in functionally graded (FG) plates. • Effect of material grading index on deformations, stresses and natural frequency of FG plates is studied. • Effect of higher order terms in displacement models is studied for plate statics. • The benchmark solutions for the static analysis and free vibration of thick FG plates are presented. -- Abstract: Functionally graded materials (FGMs) are the potential candidates under consideration for designing the first wall of fusion reactors with a view to make best use of potential properties of available materials under severe thermo-mechanical loading conditions. A higher order shear and normal deformations plate theory is employed for stress and free vibration analyses of functionally graded (FG) elastic, rectangular, and simply (diaphragm) supported plates. Although FGMs are highly heterogeneous in nature, they are generally idealized as continua with mechanical properties changing smoothly with respect to spatial coordinates. The material properties of FG plates are assumed here to vary through thickness of plate in a continuous manner. Young's modulii and material densities are considered to be varying continuously in thickness direction according to volume fraction of constituents which are mathematically modeled here as exponential and power law functions. The effects of variation of material properties in terms of material gradation index on deformations, stresses and natural frequency of FG plates are investigated. The accuracy of present numerical solutions has been established with respect to exact three-dimensional (3D) elasticity solutions and the other models’ solutions available in literature

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.

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)

Characterization of graded iron / tungsten layers for the first wall of fusion reactors

International Nuclear Information System (INIS)

Heuer, Simon

2017-01-01

The nuclear fusion has great potential to enable a CO 2 -neutral energy supply of future generations. The technical utilization of this energy source has hitherto been a challenge. In particular, high thermal loads and neutron-induced damage lead to extreme demands on the choice of materials for plasma-facing components (PFCs). These are therefore, as currently understood, made from a tungsten protective layer which is joined to a structure of low activation ferritic-martensitic (LAFM) steel. Due to the discrete transition of material properties at the LAFM-W joining zone as well as thermal loads, macroscopic stresses and plastic strains arise here. A feasible way to reduce this is to implement an intermediate layer with graded LAFM / W ratio, a so-called functional graded material (FGM). In the present work, macro-stresses and strains in the first wall of the fusion reactor DEMO are examined and evaluated by means of a finite element simulation. In this framework model components with and without graded interlayer are taken into account and the advantage of a FGM is emphasized. Parameter studies serve as a constructive guideline for the structural implementation of FGMs and components of the first wall. In addition, the feasibility of four methods (magnetron sputtering, liquid phase infiltration, modified atmospheric plasma spraying and electrodischarge sintering) with respect to the fabrication of FGMs is being studied. The resulting layers are microstructurally, thermo-physically and mechanically examined in detail. Based on this characterization and the finite element simulation, their suitability as a graded layer in the first wall of DEMO is evaluated and finally compared with alternative joining systems that are currently being tested in the research environment. [de

Thermoelastic analysis of non-uniform pressurized functionally graded cylinder with variable thickness using first order shear deformation theory(FSDT) and perturbation method

Science.gov (United States)

Khoshgoftar, M. J.; Mirzaali, M. J.; Rahimi, G. H.

2015-11-01

Recently application of functionally graded materials(FGMs) have attracted a great deal of interest. These materials are composed of various materials with different micro-structures which can vary spatially in FGMs. Such composites with varying thickness and non-uniform pressure can be used in the aerospace engineering. Therefore, analysis of such composite is of high importance in engineering problems. Thermoelastic analysis of functionally graded cylinder with variable thickness under non-uniform pressure is considered. First order shear deformation theory and total potential energy approach is applied to obtain the governing equations of non-homogeneous cylinder. Considering the inner and outer solutions, perturbation series are applied to solve the governing equations. Outer solution for out of boundaries and more sensitive variable in inner solution at the boundaries are considered. Combining of inner and outer solution for near and far points from boundaries leads to high accurate displacement field distribution. The main aim of this paper is to show the capability of matched asymptotic solution for different non-homogeneous cylinders with different shapes and different non-uniform pressures. The results can be used to design the optimum thickness of the cylinder and also some properties such as high temperature residence by applying non-homogeneous material.

Functionally graded material of 304L stainless steel and inconel 625 fabricated by directed energy deposition: Characterization and thermodynamic modeling

International Nuclear Information System (INIS)

Carroll, Beth E.; Otis, Richard A.; Borgonia, John Paul; Suh, Jong-ook; Dillon, R. Peter; Shapiro, Andrew A.; Hofmann, Douglas C.; Liu, Zi-Kui; Beese, Allison M.

2016-01-01

Many engineering applications, particularly in extreme environments, require components with properties that vary with location in the part. Functionally graded materials (FGMs), which possess gradients in properties such as hardness or density, are a potential solution to address these requirements. The laser-based additive manufacturing process of directed energy deposition (DED) can be used to fabricate metallic parts with a gradient in composition by adjusting the volume fraction of metallic powders delivered to the melt pool as a function of position. As this is a fusion process, secondary phases may develop in the gradient zone during solidification that can result in undesirable properties in the part. This work describes experimental and thermodynamic studies of a component built from 304L stainless steel incrementally graded to Inconel 625. The microstructure, chemistry, phase composition, and microhardness as a function of position were characterized by microscopy, energy dispersive spectroscopy, X-ray diffraction, and microindentation. Particles of secondary phases were found in small amounts within cracks in the gradient zone. These were ascertained to consist of transition metal carbides by experimental results and thermodynamic calculations. The study provides a combined experimental and thermodynamic computational modeling approach toward the fabrication and evaluation of a functionally graded material made by DED additive manufacturing.

Coupled DQ-FE methods for two dimensional transient heat transfer analysis of functionally graded material

Energy Technology Data Exchange (ETDEWEB)

Golbahar Haghighi, M.R.; Eghtesad, M. [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Malekzadeh, P. [Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Boushehr 75169-13798 (Iran, Islamic Republic of)], E-mail: malekzadeh@pgu.ac.ir

2008-05-15

In this paper, a mixed finite element (FE) and differential quadrature (DQ) method as a simple, accurate and computationally efficient numerical tool for two dimensional transient heat transfer analysis of functionally graded materials (FGMs) is developed. The method benefits from the high accuracy, fast convergence behavior and low computational efforts of the DQ in conjunction with the advantages of the FE method in general geometry, loading and systematic boundary treatment. Also, the boundary conditions at the top and bottom surfaces of the domain can be implemented more precisely and in strong form. The temporal derivatives are discretized using an incremental DQ method (IDQM), whose numerical stability is not sensitive to time step size. The effects of non-uniform convective-radiative conditions on the boundaries are investigated. The accuracy of the proposed method is demonstrated by comparing its results with those available in the literature. It is shown that using few grid points, highly accurate results can be obtained.

Parametric study of development of Inconel-steel functionally graded materials by laser direct metal deposition

International Nuclear Information System (INIS)

Shah, Kamran; Haq, Izhar ul; Khan, Ashfaq; Shah, Shaukat Ali; Khan, Mushtaq; Pinkerton, Andrew J

2014-01-01

Highlights: • Functionally graded steel and nickel super-alloy structures have been developed. • Mechanical properties of FGMs can be controlled by process input parameters. • SDAS is strongly dependent on the laser power and powder mass flow rate. • Carbides provide a mechanism to control the hardness and wear resistance of FGM. • Tensile strength of FGM is dependent on the laser power and powder mass flow rate. - Abstract: Laser direct metal deposition (LDMD) has developed from a prototyping to a single and multiple metals manufacturing technique. It offers an opportunity to produce graded components, with differing elemental composition, phase and microstructure at different locations. In this work, continuously graded Stainless Steel 316L and Inconel 718 thin wall structures made by direct laser metal deposition process have been explored. The paper considers the effects of process parameters including laser power levels and powder mass flow rates of SS316L and Inconel 718 during the deposition of the Steel–Ni graded structures. Microstructure characterisation and phase identification are performed by optical microscopy and X-ray diffraction techniques. Mechanical testing, using methods such as hardness, wear resistance and tensile testing have been carried out on the structures. XRD results show the presence of the NbC and Fe 2 Nb phases formed during the deposition. The effect of experimental parameters on the microstructure and physical properties are determined and discussed. Work shows that mechanical properties can be controlled by input parameters and generation of carbides provides an opportunity to selectively control the hardness and wear resistance of the functionally graded material

Orientation of Al3Ti platelets in Al-Al3Ti functionally graded material manufactured by centrifugal method

International Nuclear Information System (INIS)

Watanabe, Y.; Fukui, Y.

1997-01-01

Al-Al 3 Ti functionally graded materials (FGMs) were manufactured by the centrifugal method with a commercial ingot of Al-5 mass% Ti master alloy. The alloy was melted at a liquid/solid coexisting temperature, at which Al 3 Ti remains as a solid, and then it was cast into a thick-walled ring. It was found that the Al-Al 3 Ti functionally graded material can be successfully fabricated by the centrifugal method. It was also found that the volume fraction of the Al 3 Ti can be increased by repetition of the centrifugal method. Since the shape of Al 3 Ti particles in a commercial alloy ingot is that of a platelet, the Al 3 Ti particles are arranged with their platelet planes nearly perpendicular to the radial direction. The orientation effects become stronger when the G number becomes larger. Although the final centrifugal casting was conducted under a very large centrifugal force for the specimen cast three times, the orientation effects were weaker than those in the specimen cast one time. From these observations, it is concluded that the origin of orientation of Al 3 Ti platelets can be attributed to the angular velocity gradient of the melt along the radial direction produced by the difference in the viscosity. (orig.)

Corrosion and wear behavior of functionally graded Al2024/SiC composites produced by hot pressing and consolidation

Energy Technology Data Exchange (ETDEWEB)

Erdemir, Fatih; Canakci, Aykut, E-mail: aykut@ktu.edu.tr; Varol, Temel; Ozkaya, Serdar

2015-09-25

Highlights: • Functionally graded Al2024/SiC composites were produced by hot pressing. • Effect of the number of graded layers was investigated on the corrosion behavior. • Functionally graded composites has the most corrosion resistant than composites. • Wear mechanisms of Al2024/SiC composites were explained. - Abstract: Functionally graded Al2024/SiC composites (FGMs) with varying percentage of SiC (30–60%) were produced by hot pressing and consolidation method. The effects of SiC content and number of layers of Al2024/SiC FGMs on the corrosion and wear behaviors were investigated. The microstructures of these composites were characterized by a scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The corrosion performances of composites were evaluated by potentiodynamic polarization scans in 3.5% NaCl solution. Corrosion experiments shows that corrosion rate (1109 mpy) of two layered FGMs which containing 50 wt.% SiC were much higher than Al2024 matrix (2569 mpy) and Al2024/50 wt.% SiC composite (2201 mpy). Mechanical properties of these composites were evaluated by microhardness measurements and ball-on-disk wear tests. As the applied load change from 15 to 20 N, the wear rates of the Al2024 increased significantly and wear mechanism transformed from mild to severe wear regime. It has been shown that Al2024/40 wt.% SiC composite has lower wear rate where adhesive and abrasive wear mechanisms play a major role.

Characterization of graded iron / tungsten layers for the first wall of fusion reactors; Charakterisierung gradierter Eisen/Wolfram-Schichten fuer die erste Wand von Fusionsreaktoren

Energy Technology Data Exchange (ETDEWEB)

Heuer, Simon

2017-07-01

The nuclear fusion has great potential to enable a CO{sub 2}-neutral energy supply of future generations. The technical utilization of this energy source has hitherto been a challenge. In particular, high thermal loads and neutron-induced damage lead to extreme demands on the choice of materials for plasma-facing components (PFCs). These are therefore, as currently understood, made from a tungsten protective layer which is joined to a structure of low activation ferritic-martensitic (LAFM) steel. Due to the discrete transition of material properties at the LAFM-W joining zone as well as thermal loads, macroscopic stresses and plastic strains arise here. A feasible way to reduce this is to implement an intermediate layer with graded LAFM / W ratio, a so-called functional graded material (FGM). In the present work, macro-stresses and strains in the first wall of the fusion reactor DEMO are examined and evaluated by means of a finite element simulation. In this framework model components with and without graded interlayer are taken into account and the advantage of a FGM is emphasized. Parameter studies serve as a constructive guideline for the structural implementation of FGMs and components of the first wall. In addition, the feasibility of four methods (magnetron sputtering, liquid phase infiltration, modified atmospheric plasma spraying and electrodischarge sintering) with respect to the fabrication of FGMs is being studied. The resulting layers are microstructurally, thermo-physically and mechanically examined in detail. Based on this characterization and the finite element simulation, their suitability as a graded layer in the first wall of DEMO is evaluated and finally compared with alternative joining systems that are currently being tested in the research environment. [German] Die Kernfusion besitzt grosses Potenzial eine CO{sub 2}-neutrale Energieversorgung zukuenftiger Generationen zu ermoeglichen. Dabei stellt die technische Nutzbarmachung dieser

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.

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.

Study on the preparation of the SiCp/Al-20Si-3Cu functionally graded material using spray deposition

International Nuclear Information System (INIS)

Su, B.; Yan, H.G.; Chen, G.; Shi, J.L.; Chen, J.H.; Zeng, P.L.

2010-01-01

Research highlights: → The SiCp/Al-20Si-3Cu functionally gradient material (FGM) was successfully prepared via the spray deposition technique. → The SiCp/Al-20Si-3Cu functionally gradient material (FGM) was successfully prepared via the spray deposition technique. → In the experimental setup, the novel devices play an important role in adjusting the output of SiCp to prepare the FGM. → The experiment results reveal that the SiCp weight fraction of the as-deposited preform from the top to the bottom ranges almost continuously from 0% to 30%. → The fraction of SiC particles has no obvious influence on the phase constitutions of the SiCp/Al-20Si-3Cu FGM. - Abstract: The SiCp/Al-20Si-3Cu functionally gradient material (FGMs) was successfully prepared via the spray deposition technique accompanied with an automatic control system. The results reveal that the SiCp weight fraction of the as-deposited preform from the top to the bottom ranges almost continuously from 0% to 30%. The part with the higher SiCp weight fraction exhibits a relatively smaller density than that with the lower SiCp weight fraction. However, the microhardness and the porosity increase with the increasing SiCp weight fraction in the as-deposited preform. The X-ray diffraction results exhibit that the secondary phases in the regions with the different amount of SiC particles are the same such as Al 2 Cu and AlCuMg. The spray deposition technology is promising to produce a wide range of other FGMs.

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

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.

Cracks in functionally graded materials

International Nuclear Information System (INIS)

Bahr, H.-A.; Balke, H.; Fett, T.; Hofinger, I.; Kirchhoff, G.; Munz, D.; Neubrand, A.; Semenov, A.S.; Weiss, H.-J.; Yang, Y.Y.

2003-01-01

The weight function method is described to analyze the crack growth behavior in functionally graded materials and in particular materials with a rising crack growth resistance curve. Further, failure of graded thermal barrier coatings (TBCs) under cyclic surface heating by laser irradiation is modeled on the basis of fracture mechanics. The damage of both graded and non-graded TBCs is found to develop in several distinct stages: vertical cracking→delamination→blistering→spalling. This sequence can be understood as an effect of progressive shrinkage due to sintering and high-temperature creep during thermal cycling, which increases the energy-release rate for vertical cracks which subsequently turn into delamination cracks. The results of finite element modeling, taking into account the TBC damage mechanisms, are compatible with experimental data. An increase of interface fracture toughness due to grading and a decrease due to ageing have been measured in a four-point bending test modified by a stiffening layer. Correlation with the damage observed in cyclic heating is discussed. It is explained in which way grading is able to reduce the damage

Functionally Graded Material: An overview

CSIR Research Space (South Africa)

Mahamood, RM

2012-07-01

Full Text Available -3146. [50] X. Jin, L. Wu, L. Guo, H. Yu, and Y. Sun, ?Experimental investigation of the mixed-mode crack propagation in ZrO2/NiCr functionally graded materials,? Engineering Fracture Mechanics, vol. 76(12), (2009), pp. 1800-1810. [51] Z. Cheng, D. Gao... by stable crack growth,? Engineering Fracture Mechanics, vol.72(15), (2005), pp. 2359-2372. [47] Z.-H. Jin, and R.H. Dodds Jr, ?Crack growth resistance behavior of a functionally graded material: computational studies,? Engineering Fracture Mechanics...

Dynamic propagation of a weak-discontinuous interface crack between two dissimilar functionally graded layers under anti-plane shear

International Nuclear Information System (INIS)

Shin, Jeong Woo; Lee, Young Shin

2011-01-01

The dynamic propagation of an interface crack between two functionally graded material (FGM) layers under anti-plane shear is analyzed using the integral transform method. The properties of the FGM layers vary continuously along their thicknesses. The properties of the two FGM layers vary and the two layers are connected weak-discontinuously. A constant velocity Yoffe-type moving crack is considered. The Fourier transform is used to reduce the problem to a dual integral equation, which is then expressed to a Fredholm integral equation of the second kind. Numerical values on the dynamic energy release rate (DERR) are presented for the FGM to show the effect of the gradient of material properties, crack moving velocity, and thickness of FGM layers. The following are helpful to increase resistance to interface crack propagation in FGMs: a) increasing the gradient of material properties, b) an increase of shear modulus and density from the interface to the upper and lower free surface, and c) increasing the thickness of the FGM layer. The DERR increases or decreases with increase of the crack moving velocity

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.

Free Vibration Analysis of Functionally Graded Porous Doubly-Curved Shells Based on the First-Order Shear Deformation Theory

Directory of Open Access Journals (Sweden)

Farajollah Zare Jouneghani

2017-12-01

Full Text Available Due to some technical issues that can appear during the manufacturing process of Functionally Graded Materials (FGMs, it can be extremely difficult to produce perfect materials. Indeed, one of the biggest problems is the presence of porosities. For this purpose, the vibrational behavior of doubly-curved shells made of FGM including porosities is investigated in this paper. With respect to previous research, the porosity has been added to the mechanical model that characterizes the through-the-thickness distribution of the graded constituents and applied to doubly-curved shell structures. Few papers have been published on this topic. In fact, it is easier to find works related to one-dimensional structures and beam models that take account the effect of porosities. The First-order Shear Deformation Theory (FSDT is considered as the theoretical framework. In addition, the mechanical properties of the constituents vary along the thickness direction. For this purpose, two power-law distributions are employed to characterize their volume fraction. Strain components are established in an orthogonal curvilinear coordinate system and the governing equations are derived according to the Hamilton’s principle. Finally, Navier’s solution method is used and the numerical results concerning three different types of shell structures are presented.

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.

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.

Fracture Analysis of Functionally Graded Materials

International Nuclear Information System (INIS)

Zhang, Ch.; Gao, X. W.; Sladek, J.; Sladek, V.

2010-01-01

This paper reports our recent research works on crack analysis in continuously non-homogeneous and linear elastic functionally graded materials. A meshless boundary element method is developed for this purpose. Numerical examples are presented and discussed to demonstrate the efficiency and the accuracy of the present numerical method, and to show the effects of the material gradation on the crack-opening-displacements and the stress intensity factors.

Controlling Thermal Conduction by Graded Materials

Science.gov (United States)

Ji, Qin; Huang, Ji-Ping

2018-04-01

Manipulating thermal conductivities are fundamentally important for controlling the conduction of heat at will. Thermal cloaks and concentrators, which have been extensively studied recently, are actually graded materials designed according to coordinate transformation approaches, and their effective thermal conductivity is equal to that of the host medium outside the cloak or concentrator. Here we attempt to investigate a more general problem: what is the effective thermal conductivity of graded materials? In particular, we perform a first-principles approach to the analytic exact results of effective thermal conductivities of materials possessing either power-law or linear gradation profiles. On the other hand, by solving Laplace’s equation, we derive a differential equation for calculating the effective thermal conductivity of a material whose thermal conductivity varies along the radius with arbitrary gradation profiles. The two methods agree with each other for both external and internal heat sources, as confirmed by simulation and experiment. This work provides different methods for designing new thermal metamaterials (including thermal cloaks and concentrators), in order to control or manipulate the transfer of heat. Support by the National Natural Science Foundation of China under Grant No. 11725521, by the Science and Technology Commission of Shanghai Municipality under Grant No. 16ZR1445100

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 the basis of the same type of information which is normally collected as a part of the quality control procedures and furthermore, how the efficiency of different control procedures may be quantified and compared. The tail behavior of the probability distributions of timber material characteristics plays...... such that they may readily be applied in structural reliability analysis and their format appears to be appropriate for codification purposes of quality control and selection for grading procedures....

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...

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…

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.

German 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 German 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 German Language and Culture Nine-year…

Punjabi 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 Punjabi 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 Punjabi Language and Culture Nine-year…

The Application of materials attractiveness in a graded approach to nuclear materials security

International Nuclear Information System (INIS)

Ebbinghaus, B.; Bathke, C.; Dalton, D.; Murphy, J.

2013-01-01

The threat from terrorist groups has recently received greater attention. In this paper, material quantity and material attractiveness are addressed through the lens of a minimum security strategy needed to prevent the construction of a nuclear explosive device (NED) by an adversary. Nuclear materials are placed into specific security categories (3 or 4 categories) , which define a number of security requirements to protect the material. Materials attractiveness can be divided into four attractiveness levels, High, Medium, Low, and Very Low that correspond to the utility of the material to the adversary and to a minimum security strategy that is necessary to adequately protect the nuclear material. We propose a graded approach to materials attractiveness that recognizes for instance substantial differences in attractiveness between pure reactor-grade Pu oxide (High attractiveness) and fresh MOX fuel (Low attractiveness). In either case, an adversary's acquisition of a Category I quantity of plutonium would be a major incident, but the acquisition of Pu oxide by the adversary would be substantially worse than the acquisition of fresh MOX fuel because of the substantial differences in the time and complexity required of the adversary to process the material and fashion it into a NED

Job Grading Standard for Materials Expediter WG-6705.

Science.gov (United States)

Civil Service Commission, Washington, DC. Bureau of Policies and Standards.

The standard is used to grade nonsupervisory jobs involved in routing and expediting the movement of parts, end items, supplies, and materials within production and repair facilities to meet priority needs. The work requires knowledge of material characteristics, uses, condition, industrial production shop procedures, shop layout, and internal…

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)

The Application of materials attractiveness in a graded approach to nuclear materials security

Energy Technology Data Exchange (ETDEWEB)

Ebbinghaus, B. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Bathke, C. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Dalton, D.; Murphy, J. [National Nuclear Security Administration, US Department of Energy, 1000 Independent Ave., S. W. Washington, DC 20585 (United States)

2013-07-01

The threat from terrorist groups has recently received greater attention. In this paper, material quantity and material attractiveness are addressed through the lens of a minimum security strategy needed to prevent the construction of a nuclear explosive device (NED) by an adversary. Nuclear materials are placed into specific security categories (3 or 4 categories) , which define a number of security requirements to protect the material. Materials attractiveness can be divided into four attractiveness levels, High, Medium, Low, and Very Low that correspond to the utility of the material to the adversary and to a minimum security strategy that is necessary to adequately protect the nuclear material. We propose a graded approach to materials attractiveness that recognizes for instance substantial differences in attractiveness between pure reactor-grade Pu oxide (High attractiveness) and fresh MOX fuel (Low attractiveness). In either case, an adversary's acquisition of a Category I quantity of plutonium would be a major incident, but the acquisition of Pu oxide by the adversary would be substantially worse than the acquisition of fresh MOX fuel because of the substantial differences in the time and complexity required of the adversary to process the material and fashion it into a NED.

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.

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.

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

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 ...

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

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 ...

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.

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

Y2O3-W Continuous Graded Materials by Co-sedimentation

Directory of Open Access Journals (Sweden)

WANG Shi-yang

2017-09-01

Full Text Available The raw Y2O3 powder was classified and graded based on modified co-sedimentation mathematical model,using the size distribution of W particles as the known condition. Y2O3-W continuous graded materials with the composition distribution index P values of 1.0, 0.7, 0.3 and 0.1 were prepared by co-sedimentation and hot-pressing. The results show that the Y2O3 powder consistent with the design requirements can be obtained by graduation method. The gradient continuity of materials can be verified by microstructure observation and hardness testing.

Functionally graded materials for impedance matching in elastic media

International Nuclear Information System (INIS)

Chen, Shi; Zhang, Yinhong; Hao, Changchun; Lin, Shuyu; Fu, Zhiqiang

2014-01-01

When functionally graded material layers are inserted between two impedance mismatching media, passbands with extremely large bandwidths can appear in these layered systems. An accurate and effective iterative method is developed to deal with these layered systems with extremely large layer number.

Functionally graded materials for impedance matching in elastic media

Energy Technology Data Exchange (ETDEWEB)

Chen, Shi; Zhang, Yinhong, E-mail: zyh5337@163.com; Hao, Changchun; Lin, Shuyu; Fu, Zhiqiang

2014-01-03

When functionally graded material layers are inserted between two impedance mismatching media, passbands with extremely large bandwidths can appear in these layered systems. An accurate and effective iterative method is developed to deal with these layered systems with extremely large layer number.

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

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.

The compatibility approach in the classical theory of thermoelectricity seen from the perspective of variational calculus

Energy Technology Data Exchange (ETDEWEB)

Seifert, Wolfgang [Institute of Physics, Martin Luther University, Halle-Wittenberg (Germany); Zabrocki, Knud; Mueller, Eckhard [Institute of Materials Research, German Aerospace Center (DLR), 51170 Koeln (Germany); Snyder, G.J. [California Institute of Technology, Pasadena, California 91125 (United States)

2010-03-15

The compatibility approach introduced by Snyder and Ursell opens a new pathway for the improvement of thermoelectric (TE) device performance. It has been shown that sufficient compatibility is - besides an increase of the averaged figure of merit Z - essential for efficient operation of a TE device, and that compatibility will facilitate rational materials selection, device design, and the engineering of functionally graded materials (FGMs). In this paper, the authors give an overview of the fundamental results and present a new approach from the perspective of variational calculus. A particular focus is on the role of ideal self-compatibility, i.e., adjusting compatibility locally at any position along a TE leg. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

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)

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.

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

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.)

Preparation of Al/Si functionally graded materials using ultrasonic separation method

Directory of Open Access Journals (Sweden)

Zhang Zhongtao

2008-08-01

Full Text Available Functionally graded materials (FGM have been widely used in many industries such as aerospace, energy and electronics. In this experimental study of fabricating FGM, an approach was developed to prepare Al/Si FGM using power ultrasonic separation method. Material sample with continuously changing composition and performance/properties was successfully produced. Results showed that the microstructure of the FGM sample transited, from its top to bottom, from the hypereutectic structure with a large quantity of primary Si gradually to the eutectic, and fi nally to the hypoeutectic with numerous primary Al dendrites. The distribution of primary Si and microhardness of the FGM sample also presented graded characteristics, resulting that the wear resistance of the FGM sample decreased from top to bottom. Preliminary discussion was made on the mechanism of the formation of Al/Si FGM.

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

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.)

Design of an Online Fission Gas Monitoring System for Post-irradiation Examination Heating Tests of Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

Energy Technology Data Exchange (ETDEWEB)

Dawn Scates

2010-10-01

A new Fission Gas Monitoring System (FGMS) has been designed at the Idaho National Laboratory (INL) for use of monitoring online fission gas-released during fuel heating tests. The FGMS will be used with the Fuel Accident Condition Simulator (FACS) at the Hot Fuels Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) within the INL campus. Preselected Advanced Gas Reactor (AGR) TRISO (Tri-isotropic) fuel compacts will undergo testing to assess the fission product retention characteristics under high temperature accident conditions. The FACS furnace will heat the fuel to temperatures up to 2,000ºC in a helium atmosphere. Released fission products such as Kr and Xe isotopes will be transported downstream to the FGMS where they will accumulate in cryogenically cooledcollection traps and monitored with High Purity Germanium (HPGe) detectors during the heating process. Special INL developed software will be used to monitor the accumulated fission products and will report data in near real-time. These data will then be reported in a form that can be readily available to the INL reporting database. This paper describes the details of the FGMS design, the control and acqusition software, system calibration, and the expected performance of the FGMS. Preliminary online data may be available for presentation at the High Temperature Reactor (HTR) conference.

Thermal behavior of the duct applied functionally graded material

Energy Technology Data Exchange (ETDEWEB)

Park, Jung Sun; Yoon, Dong Young; Im, Jong Bin [Hankuk Aviation Univ., Goyang (Korea, Republic of)

2004-07-01

In Unmanned Aerial Vehicles (UAV), the high temperature results from friction among the air, combustion of fuel in engine and combustion gas of a nozzle. The high temperature may cause serious damages in UAV structure. The Functionally Graded Material(FGM) is chosen as a material of the engine duct structure. Thermal stress analysis of FGM is performed in this paper. FGM is composed of two constituent materials that are mixed up according to the specific volume fraction distribution in order to withstand high temperature. Therefore, hoop stress, axial stress and shear stress of duct with 2 layers, 4 layers and 8 layers FGM are compared and analyzed respectively. In addition, the creep behavior of FGM used in duct structure of an engine is analyzed for better understanding of FGM characteristics.

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.

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

Micromechanical models for graded composite materials

DEFF Research Database (Denmark)

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

1997-01-01

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...... fields are predicted by Mori-Tanaka estimates. On the other hand, the response of graded materials with a skeletal microstructure in a wide transition zone between clearly defined matrix phases is better approximated by the self-consistent estimates. Certain exceptions are noted for loading by overall...... transverse shear stress; The results suggest that the averaging methods originally developed for statistically homogeneous aggregates may be selectively applied, with a reasonable degree of confidence, to aggregates dth composition gradients, subjected to both uniform and nonuniform overall loads. (C) 1997...

Content, format, gender and grade level differences in elementary students' ability to read science materials as measured by the cloze procedure

Science.gov (United States)

Williams, Richard L.; Yore, Larry D.

Present instructional trends in science indicate a need to reexamine a traditional concern in science education: the readability of science textbooks. An area of reading research not well documented is the effect of color, visuals, and page layout on readability of science materials. Using the cloze readability method, the present study explored the relationships between page format, grade level, sex, content, and elementary school students ability to read science material. Significant relationships were found between cloze scores and both grade level and content, and there was a significant interaction effect between grade and sex in favor of older males. No significant relationships could be attributed to page format and sex. In the area of science content, biological materials were most difficult in terms of readability followed by earth science and physical science. Grade level data indicated that grade five materials were more difficult for that level than either grade four or grade six materials were for students at each respective level. In eight of nine cases, the science text materials would be classified at or near the frustration level of readability. The implications for textbook writers and publishers are that science reading materials need to be produced with greater attention to readability and known design principles regarding visual supplements. The implication for teachers is that students need direct instruction in using visual materials to increase their learning from text material. Present visual materials appear to neither help nor hinder the student to gain information from text material.

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.

An Overview of Promising Grades of Tool Materials Based on the Analysis of their Physical-Mechanical Characteristics

Science.gov (United States)

Kudryashov, E. A.; Smirnov, I. M.; Grishin, D. V.; Khizhnyak, N. A.

2018-06-01

The work is aimed at selecting a promising grade of a tool material, whose physical-mechanical characteristics would allow using it for processing the surfaces of discontinuous parts in the presence of shock loads. An analysis of the physical-mechanical characteristics of most common tool materials is performed and the data on a possible provision of the metal-working processes with promising composite grades are presented.

Deposition and Characterization of HVOF Thermal Sprayed Functionally Graded Coatings Deposited onto a Lightweight Material

Science.gov (United States)

Hasan, M.; Stokes, J.; Looney, L.; Hashmi, M. S. J.

2009-02-01

There is a significant interest in lightweight materials (like aluminum, magnesium, titanium, and so on) containing a wear resistance coating, in such industries as the automotive industry, to replace heavy components with lighter parts in order to decrease vehicle weight and increase fuel efficiency. Functionally graded coatings, in which the composition, microstructure, and/or properties vary gradually from the bond coat to the top coat, may be applied to lightweight materials, not only to decrease weight, but also to enhance components mechanical properties by ensuring gradual microstructural (changes) together with lower residual stress. In the current work, aluminum/tool-steel functionally graded coatings were deposited onto lightweight aluminum substrates. The graded coatings were then characterized in terms of residual stress and hardness. Results show that residual stress increased with an increase in deposition thickness and a decrease in number of layers. However, the hardness also increased with an increase in deposition thickness and decrease in number of layers. Therefore, an engineer must compromise between the hardness and stress values while designing a functionally graded coating-substrate system.

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

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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.

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,…

Elasto-Plastic Stress Analysis in Rotating Disks and Pressure Vessels Made of Functionally Graded Materials

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Amir T. Kalali

Full Text Available Abstract A new elastio-plastic stress solution in axisymmetric problems (rotating disk, cylindrical and spherical vessel is presented. The rotating disk (cylindrical and spherical vessel was made of a ceramic/metal functionally graded material, i.e. a particle-reinforced composite. It was assumed that the material's plastic deformation follows an isotropic strain-hardening rule based on the von-Mises yield criterion. The mechanical properties of the graded material were modeled by the modified rule of mixtures. By assuming small strains, Hencky's stress-strain relation was used to obtain the governing differential equations for the plastic region. A numerical method for solving those differential equations was then proposed that enabled the prediction of stress state within the structure. Selected finite element results were also presented to establish supporting evidence for the validation of the proposed approach.

Nutrition Education Materials: Grades Preschool through 6. 1979-March 1987. Quick Bibliography Series.

Science.gov (United States)

Irving, Holly Berry

The citations in this annotated bibliography are of audiovisuals and books focusing on basic nutrition education for children in preschool through the sixth grade. There are 306 citations derived from online searches of the AGRICOLA database. Information is provided on obtaining the materials. (JD)

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

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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  |

Analysis of the conductivity of commercial easy sintering grade 3 mol% Y{sub 2}O{sub 3}-ZrO{sub 2} materials

Energy Technology Data Exchange (ETDEWEB)

Badwal, Sukhvinder P.S.; Ciacchi, Fabio T.; Giampietro, Kristine M. [CSIRO, Manufacturing and Infrastructure Technology, Private Bag 33, Clayton South 3169, Victoria (Australia)

2005-01-14

Fine grain zirconia-yttria materials are required for enhanced performance in solid oxide fuel cells and related devices and in applications requiring good thermo-mechanical properties. Materials with about 3 mol% Y{sub 2}O{sub 3}-ZrO{sub 2} composition are good electrolyte materials for solid oxide fuel cell, ceramic membrane oxygen separation and a number of related devices because of their superior mechanical properties and ease of fabrication into thin self-supporting structures in comparison with a material in the 8-10 mol% Y{sub 2}O{sub 3}-ZrO{sub 2} composition range. In this study, sintering behaviour, impedance studies, four-probe DC conductivity measurements and microstructure analysis has been performed on various easy sintering grade materials from two commercial powder suppliers. These materials achieve near theoretical density at sintering temperatures as low as 1350-1400C. For direct comparison of the conductivity and impedance behaviour in easy sintering grade materials, several other 3 mol% Y{sub 2}O{sub 3}-ZrO{sub 2} powders were also investigated. The total ionic conductivity at 850C in easy sintering grade materials is comparable with normal-grade commercial materials of similar composition despite a slightly higher grain boundary impedance at lower temperatures (below circa 450C). There were no obvious differences in the grain boundary thickness, calculated from the impedance data, of normal and easy sintering grade materials.

Will bottle-grade PET demand lure fiber-grade capacity?

International Nuclear Information System (INIS)

Coeyman, M.

1993-01-01

As demand for bottle-grade polyethylene terephthalate (PET) continues strong and new capacity hastens to meet it, some industry observers wonder if conversions to bottle-grade from fiber-grade capacity will become an industry trend. Taiwan's Nan Ya Plastics was recently said to be considering such a switch, but company sources say it has no such plans. Peter Driscoll, senior partner at PCI Fibres ampersand Raw Materials (Crawley, UK), says that while it is true that demand for the bottle-grade material remains unsatisfied, he doubts that many conversions will take place. You must remember, says Driscoll, that it is not always possible to switch, and that even where it is possible there are limitations

Chemical vapor deposition of refractory metals and ceramics III

International Nuclear Information System (INIS)

Gallois, B.M.; Lee, W.Y.; Pickering, M.A.

1995-01-01

The papers contained in this volume were originally presented at Symposium K on Chemical Vapor Deposition of Refractory Metals and Ceramics III, held at the Fall Meeting of the Materials Research Society in Boston, Massachusetts, on November 28--30, 1994. This symposium was sponsored by Morton International Inc., Advanced Materials, and by The Department of Energy-Oak Ridge National Laboratory. The purpose of this symposium was to exchange scientific information on the chemical vapor deposition (CVD) of metallic and ceramic materials. CVD technology is receiving much interest in the scientific community, in particular, to synthesize new materials with tailored chemical composition and physical properties that offer multiple functionality. Multiphase or multilayered films, functionally graded materials (FGMs), ''smart'' material structures and nanocomposites are some examples of new classes of materials being produced via CVD. As rapid progress is being made in many interdisciplinary research areas, this symposium is intended to provide a forum for reporting new scientific results and addressing technological issues relevant to CVD materials and processes. Thirty four papers have been processed separately for inclusion on the data base

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…

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)

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

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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.

Elaboration of functionally graded materials for plasma facing components of the thermonuclear machines

International Nuclear Information System (INIS)

Autissier, Emmanuel

2014-01-01

The objective of this study was to develop a Functionally Graded Material (FGM) W/Cu to replace the compliance layer (Cu-OFHC) in the plasma facing components of thermonuclear fusion reactor like ITER. The peculiarity of this work is to elaborate these materials without exceeding the melting temperature of copper in order to control its microstructure. The co-sintering is the most attractive solution to achieve this goal. The first phase of this study has been to decrease the sintering temperature of the tungsten to achieve this co-sintering. The elaboration of a Functionally Graded Materials being delicate, thermomechanical calculations were performed in order to determine the number and chemical composition in order to increase the lifespan of Plasma Facing Components. Spark Plasma Sintering conditions were optimized in order to achieve maximum density of W x Cu 1-x composites. The effect of copper content and density of the W x Cu 1-x composites on thermal and mechanical properties was investigated. The SPS conditions were applied for W/CuCrZr assemblies with a compliance layer composed of several interlayers. The importance of time for the integrity of assemblies thereof has been highlighted. The study of the dwell time during W/CuCrZr assembly leads to identify a parameter to characterize the integrity of the interface regardless of the composition and the nature of the layer of compliance. Moreover, the phenomena associated with the formation of the interface assembly have been identified. The interface W/W x Cu 1-x is formed by the extrusion of the copper layer of the W x Cu 1-x inside the tungsten porosities. The W y Cu 1-y /CuCrZr interface is formed by copper migration of CuCrZr layer inside the W y Cu 1-y layer. Finally optimization assembly conditions showed that the mechanical stresses due to the densification of the Functionally Graded Materials can be limited by sintering the FGM before the assembly. (author)

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.

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)

Stress Distribution in Graded Cellular Materials Under Dynamic Compression

Directory of Open Access Journals (Sweden)

Peng Wang

Full Text Available Abstract Dynamic compression behaviors of density-homogeneous and density-graded irregular honeycombs are investigated using cell-based finite element models under a constant-velocity impact scenario. A method based on the cross-sectional engineering stress is developed to obtain the one-dimensional stress distribution along the loading direction in a cellular specimen. The cross-sectional engineering stress is contributed by two parts: the node-transitive stress and the contact-induced stress, which are caused by the nodal force and the contact of cell walls, respectively. It is found that the contact-induced stress is dominant for the significantly enhanced stress behind the shock front. The stress enhancement and the compaction wave propagation can be observed through the stress distributions in honeycombs under high-velocity compression. The single and double compaction wave modes are observed directly from the stress distributions. Theoretical analysis of the compaction wave propagation in the density-graded honeycombs based on the R-PH (rigid-plastic hardening idealization is carried out and verified by the numerical simulations. It is found that stress distribution in cellular materials and the compaction wave propagation characteristics under dynamic compression can be approximately predicted by the R-PH shock model.

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…

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...

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…

Boundary element method for normal non-adhesive and adhesive contacts of power-law graded elastic materials

Science.gov (United States)

Li, Qiang; Popov, Valentin L.

2018-03-01

Recently proposed formulation of the boundary element method for adhesive contacts has been generalized for contacts of power-law graded materials with and without adhesion. Proceeding from the fundamental solution for single force acting on the surface of an elastic half space, first the influence matrix is obtained for a rectangular grid. The inverse problem for the calculation of required stress in the contact area from a known surface displacement is solved using the conjugate-gradient technique. For the transformation between the stresses and displacements, the Fast Fourier Transformation is used. For the adhesive contact of graded material, the detachment criterion based on the energy balance is proposed. The method is validated by comparison with known exact analytical solutions as well as by proving the independence of the mesh size and the grid orientation.

Fracture of functionally graded materials: application to hydrided zircaloy

International Nuclear Information System (INIS)

Perales, F.

2005-12-01

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)

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.

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…

Stresses and Displacements in Functionally Graded Materials of Semi-Infinite Extent Induced by Rectangular Loadings

Directory of Open Access Journals (Sweden)

Zhong-Qi Yue

2012-01-01

Full Text Available This paper presents the stress and displacement fields in a functionally graded material (FGM caused by a load. The FGM is a graded material of Si3N4-based ceramics and is assumed to be of semi-infinite extent. The load is a distributed loading over a rectangular area that is parallel to the external surface of the FGM and either on its external surface or within its interior space. The point-load analytical solutions or so-called Yue’s solutions are used for the numerical integration over the distributed loaded area. The loaded area is discretized into 200 small equal-sized rectangular elements. The numerical integration is carried out with the regular Gaussian quadrature. Weak and strong singular integrations encountered when the field points are located on the loaded plane, are resolved with the classical methods in boundary element analysis. The numerical integration results have high accuracy.

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....

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.

General thermo-elastic solution of radially heterogeneous, spherically isotropic rotating sphere

Energy Technology Data Exchange (ETDEWEB)

Bayat, Yahya; EkhteraeiToussi, THamid [Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2015-06-15

A thick walled rotating spherical object made of transversely isotropic functionally graded materials (FGMs) with general types of thermo-mechanical boundary conditions is studied. The thermo-mechanical governing equations consisting of decoupled thermal and mechanical equations are represented. The centrifugal body forces of the rotation are considered in the modeling phase. The unsymmetrical thermo-mechanical boundary conditions and rotational body forces are expressed in terms of the Legendre series. The series method is also implemented in the solution of the resulting equations. The solutions are checked with the known literature and FEM based solutions of ABAQUS software. The effects of anisotropy and heterogeneity are studied through the case studies and the results are represented in different figures. The newly developed series form solution is applicable to the rotating FGM spherical transversely isotropic vessels having nonsymmetrical thermo-mechanical boundary condition.

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.

Functionally Graded Mo sintered steels

Directory of Open Access Journals (Sweden)

Manuel Cisneros-Belmonte

2016-12-01

Full Text Available Functionally graded materials (FGM, the multi-materials, strive to satisfy the numerous requirements demanded of parts in a given combination of compositions and microstructures. The required material compatibility lead the manufacturing process and the achieving of an interface, not always diffuse. Powder metallurgy is one of the techniques used in manufacturing functionally graded materials, in particular the compaction matrix of the possible techniques for forming these materials. In this paper, a process of forming a functionally graded steel based on the use of a high molybdenum steel with cooper and other steel with copper, without molybdenum, is proposed with the aim of concentrating this element to the surface of the workpiece, increasing the mechanical strength. The study is completed with the evaluation of physical properties (density and porosity distribution, mechanical properties (hardness, tensile strength and elongation and microstructural analysis by optical and scanning electron microscopy.

Accuracy of a Flash Glucose Monitoring System in Diabetic Dogs

OpenAIRE

Corradini, S.; Pilosio, B.; Dondi, F.; Linari, G.; Testa, S.; Brugnoli, F.; Gianella, P.; Pietra, M.; Fracassi, F.

2016-01-01

Background A novel flash glucose monitoring system (FGMS) (FreeStyle Libre, Abbott, UK) was recently developed for humans. It continuously measures the interstitial glucose (IG) concentrations for 14 days. Objectives To assess the clinical and analytical accuracy of the FGMS in diabetic dogs. Animals Ten client?owned diabetic dogs on insulin treatment. Methods Prospective and observational study. The FGMS was placed on the neck for up to 14 days. During the 1st?2nd, 6?7th, and 13?14th days fr...

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).

Bulk solar grade silicon: how chemistry and physics play to get a benevolent microstructured material

Energy Technology Data Exchange (ETDEWEB)

Pizzini, S. [University of Milano-Bicocca, Department of Materials Science, Milan (Italy); Nedsilicon SpA, Osimo, Ancona (Italy)

2009-07-15

The availability of low-cost alternatives to electronic grade silicon has been and still is the condition for the extensive use of photovoltaics as an efficient sun harvesting system. The first step towards this objective was positively carried out in the 1980s and resulted in the reduction in cost and energy of the growth process using as feedstock electronic grade scraps and a variety of solidification procedures, all of which deliver a multi-crystalline material of high photovoltaic quality. The second step was an intense R and D activity aiming at defining and developing at lab scale a new variety of silicon, called ''solar grade'' silicon, which should fulfil the requirement of both cost effectiveness and high conversion efficiency. The third step involved and still involves the development of cost-effective technologies for the manufacture of solar grade silicon, in alternative to the classical Siemens route, which relays, as is well-known, to the pyrolitic decomposition of high-purity trichlorosilane and which is, also in its more advanced versions, extremely energy intensive. Aim of this paper is to give the author's viewpoint about some open questions concerning bulk solar silicon for PV applications and about challenges and chances of novel feedstocks of direct metallurgical origin. (orig.)

Processing of W-Cu functionally graded materials (FGM) through the powder metallurgy route: application as plasma facing components for ITER-like thermonuclear fusion reactor

International Nuclear Information System (INIS)

Raharijaona, J.J.

2009-11-01

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 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)

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.

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.

A quick in-situ estimating method for grading stone products as radiation protection standard of building materials

International Nuclear Information System (INIS)

Nanping, Wang; Shengli, Hou; Yexun, Chen

2002-01-01

Natural stone is word-widely used as building and decorating material, which is made of marble, granite or other kinds of rocks. Normally they are cut into rectangle with 20 mm thickness. In order to grade small size stone plank as radioactive protection standard (China Standard GB6566-2001), a quick in-situ technique and a special kind of portable -ray detector is developed. The detector is made of NaI (Tl) ( 30x50mm) with a shield (Model ZDD3901, China Patent No. 992080045). The difference modeling was established for small-size stone planks grading. About 96.3% stone plank samples which size are more than 300x300x20 mm could be determined radiation levels by in-situ techniques, by which the grading results (A, B or C) are coincided with quantity analysis in lab

A quick in-situ estimating method for grading stone products as radiation protection standard of building materials

Energy Technology Data Exchange (ETDEWEB)

Nanping, Wang; Shengli, Hou; Yexun, Chen [China Univ. of Geosciences, Bijing (China)

2002-07-01

Natural stone is word-widely used as building and decorating material, which is made of marble, granite or other kinds of rocks. Normally they are cut into rectangle with 20 mm thickness. In order to grade small size stone plank as radioactive protection standard (China Standard GB6566-2001), a quick in-situ technique and a special kind of portable -ray detector is developed. The detector is made of NaI (Tl) ( 30x50mm) with a shield (Model ZDD3901, China Patent No. 992080045). The difference modeling was established for small-size stone planks grading. About 96.3% stone plank samples which size are more than 300x300x20 mm could be determined radiation levels by in-situ techniques, by which the grading results (A, B or C) are coincided with quantity analysis in lab.

Study of thermal conductivity and thermal rectification in exponential mass graded lattices

Energy Technology Data Exchange (ETDEWEB)

Shah, Tejal N. [Bhavan' s Sheth R.A. College of Science, Khanpur, Ahmedabad 380 001, Gujarat (India); Gajjar, P.N., E-mail: pngajjar@rediffmail.com [Department of Physics, University School of Sciences, Gujarat University, Ahmedabad 380 009, Gujarat (India)

2012-01-09

Concept of exponential mass variation of oscillators along the chain length of N oscillators is proposed in the present Letter. The temperature profile and thermal conductivity of one-dimensional (1D) exponential mass graded harmonic and anharmonic lattices are studied on the basis of Fermi–Pasta–Ulam (FPU) β model. Present findings conclude that the exponential mass graded chain provide higher conductivity than that of linear mass graded chain. The exponential mass graded anharmonic chain generates the thermal rectification of 70–75% which is better than linear mass graded materials, so far. Thus instead of using linear mass graded material, the use of exponential mass graded material will be a better and genuine choice for controlling the heat flow at nano-scale. -- Highlights: ► In PRE 82 (2010) 040101, use of mass graded material as a thermal devices is explored. ► Concept of exponential mass graded material is proposed. ► The rectification obtained is about 70–75% which is better than linear mass graded materials. ► The exponential mass graded material will be a better choice for the thermal devices at nano-scale.

Modeling Diesel engine combustion using pressure dependent Flamelet Generated Manifolds

NARCIS (Netherlands)

Bekdemir, C.; Somers, L.M.T.; Goey, de L.P.H.

2011-01-01

Flamelet Generated Manifolds (FGMs) are constructed and applied to simulations of a conventional compression ignition engine cycle. To study the influence of pressure and temperature variations on the ignition process after the compression stroke, FGMs with several pressure levels are created. These

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.

Accuracy of a Flash Glucose Monitoring System in Diabetic Dogs.

Science.gov (United States)

Corradini, S; Pilosio, B; Dondi, F; Linari, G; Testa, S; Brugnoli, F; Gianella, P; Pietra, M; Fracassi, F

2016-07-01

A novel flash glucose monitoring system (FGMS) (FreeStyle Libre, Abbott, UK) was recently developed for humans. It continuously measures the interstitial glucose (IG) concentrations for 14 days. To assess the clinical and analytical accuracy of the FGMS in diabetic dogs. Ten client-owned diabetic dogs on insulin treatment. Prospective and observational study. The FGMS was placed on the neck for up to 14 days. During the 1st-2nd, 6-7th, and 13-14th days from application, the IG measurements were compared with the plasma (EDTA) glucose (PG) concentrations analyzed by a reference hexokinase based method. The application and the use of the FGMS were apparently painless, easy, and well tolerated by all dogs. Mild erythema at the site of the application was found in 5/10 dogs at the end of the wearing period. A good correlation between IG and PG concentrations (rho = 0.94; P blood glucose concentrations. Mean ± standard deviation difference from the reference method was 2.3 ± 46.8 mg/dL. The FGMS is easy to use and is accurate for IG glucose measurement in diabetic dogs. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

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

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…

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).

Material development for grade X80 heavy-wall hot induction bends

Energy Technology Data Exchange (ETDEWEB)

Wang Xu [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); CNPC Bohai Petroleum Equipment Manufacture Co. Ltd., Qingxian 062658 (China); Xiao Furen, E-mail: frxiao@ysu.edu.cn [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Fu Yanhong [CNPC Bohai Petroleum Equipment Manufacture Co. Ltd., Qingxian 062658 (China); Chen Xiaowei [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); CNPC Bohai Petroleum Equipment Manufacture Co. Ltd., Qingxian 062658 (China); Liao Bo, E-mail: cyddjyjs@263.net [Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

2011-12-15

Highlights: Black-Right-Pointing-Pointer The new material for X80 heavy wall thickness hot induction bend was designed. Black-Right-Pointing-Pointer The continuous cooling transformation (CCT) diagrams were determined. Black-Right-Pointing-Pointer The steel adapts to manufacture of X80 heavy-wall thickness hot induction bend. Black-Right-Pointing-Pointer The optimum manufactural processes were obtained. Black-Right-Pointing-Pointer The bending temperature is about 990 Degree-Sign C, and tempering is about 600 Degree-Sign 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.

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.

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…

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications

Science.gov (United States)

Eliaz, Noam; Metoki, Noah

2017-01-01

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs. PMID:28772697

Material properties of Grade 91 steel at elevated temperature and their comparison with a design code

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyeong Yeon; Kim, Woo Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Han Sang; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of)

2013-10-15

In this study, the material properties of tensile strength, creep properties, and creep crack growth model for Gr.91 steel at elevated temperature were obtained from material tests at KAERI, and the test data were compared with those of the French elevated temperature design code, RCC-MRx. The conservatism of the material properties in the French design code is highlighted. Mod.9Cr-1Mo (ASME Grade 91; Gr.91) steel is widely adopted as candidate material for Generation IV nuclear systems as well as for advanced thermal plants. In a Gen IV sodium-cooled fast reactor of the PGSFR (Prototype Gen IV Sodium-cooled Fast Reactor) being developed by KAERI (Korea Atomic Energy Research Institute), Gr.91 steel is selected as the material for the steam generator, secondary piping, and decay heat exchangers. However, as this material has a relatively shorter history of usage in an actual plant than austenitic stainless steel, there are still many issues to be addressed including the long-term creep rupture life extrapolation and ratcheting behavior with cyclic softening characteristics.

Transverse Vibration of Axially Moving Functionally Graded Materials Based on Timoshenko Beam Theory

Directory of Open Access Journals (Sweden)

Suihan Sui

2015-01-01

Full Text Available The transverse free vibration of an axially moving beam made of functionally graded materials (FGM is investigated using a Timoshenko beam theory. Natural frequencies, vibration modes, and critical speeds of such axially moving systems are determined and discussed in detail. The material properties are assumed to vary continuously through the thickness of the beam according to a power law distribution. Hamilton’s principle is employed to derive the governing equation and a complex mode approach is utilized to obtain the transverse dynamical behaviors including the vibration modes and natural frequencies. Effects of the axially moving speed and the power-law exponent on the dynamic responses are examined. Some numerical examples are presented to reveal the differences of natural frequencies for Timoshenko beam model and Euler beam model. Moreover, the critical speed is determined numerically to indicate its variation with respect to the power-law exponent, axial initial stress, and length to thickness ratio.

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.

Fatigue Characterization of Functionally Graded Metallic Alloys

International Nuclear Information System (INIS)

Silva, F. S.

2008-01-01

Functionally graded components exhibit spatial variations of mechanical properties in contrast with, and as an alternative to, purely homogeneous components. A large class of graded materials, however, are in fact mostly homogeneous materials with property variations (chemical or mechanical) restricted to a specific area or layer produced by applying for example a coating or by introducing sub-surface residual stresses. However, it is also possible to obtain graded materials with a smooth transition of mechanical properties along the entire component, for example in a 40 mm component. This is possible, for example, by using centrifugal casting technique or incremental melting and solidification technique. In this paper we will study fully metallic functionally graded components with a smooth gradient, focusing on fatigue crack propagation. Fatigue propagation will be assessed in the direction parallel to the gradation (in different homogeneous layers of the functionally graded component) to assess what would be fatigue crack propagation on the direction perpendicular to the gradation. Fatigue crack growth rate (standard mode I fatigue crack growth) will be correlated to the mode I stress intensity factor range. Other mechanical properties of different layers of the component (Young's modulus) will also be considered in this analysis. The effect of residual stresses along the component gradation on crack propagation will also be taken into account. A qualitative analysis of the effects of some important features, present in functionally graded materials, will be made based on the obtained results

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.

Optimum material gradient composition for the functionally graded ...

African Journals Online (AJOL)

user

To this end, various static tests for functionally graded ... different poling directions, high stress concentrations are usually appeared at the layer interfaces under ...... Use of classical plate finite elements for the analysis of electroactive ...

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.

Interdisciplinary Student/Teacher Materials in Energy, the Environment, and the Economy: 6, The Energy We Use, Grade 1.

Science.gov (United States)

Bloch, Lenore; And Others

This instructional unit contains a set of nine lessons on energy for grade one. Each lesson contains complete teacher and student materials. Reading skills and language experiences are reinforced in each activity. The lessons cover such topics as energy from food, energy from the sun, fossil fuels, the wind, moving water, and energy conservation.…

Effect of Different Concrete Grade on Radiation Linear Attenuation Coefficient (μ)

International Nuclear Information System (INIS)

Noor Azreen Masenwat; Mohammad Shahrizan Samsu; Mohamad Pauzi Ismail; Suhairy Sani; Ismail Mustapha; Nasharuddin Isa; Mohamad Haniza Mahmud

2014-01-01

In calculating the quantity of absorption of radiation and its relationship with the thickness of a material, linear attenuation coefficient (μ) of the material is one of the parameters to be taken into account. For normal concrete, the (μ) varies depending on the type of radiation used, 0.105 cm -1 for Co-60 and 0.123 cm -1 for Cs-137. Value (μ) is used in the calculation of the radiation absorption for concrete material does not take into account factors such concrete grades. In this research, concrete with different grades (Grade 15, Grade 20, Grade 25, Grade 30, Grade 35, Grade 40) are designed and manufactured with reference to the mixing method described in British Standard. Then, the linear attenuation (μ) for each grade are measured using the radiation from the source Co-60 and Cs-137 sources. This paper describes and discusses the impact of differences in concrete grade of linear attenuation (μ) for Co-60 source/ source Cs-137 and its relationship with the compressive strength. (author)

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).

High Efficient Enrichment and Activated Dissolution of Refractory Low Grade Rh-containing Material

Institute of Scientific and Technical Information of China (English)

WU Xiaofeng; DONG Haigang; TONG Weifeng; ZHAO Jiachun; ZENG Rui

2012-01-01

Aiming to the low-grade rhodium-containing waste materials,a new process was proposed to enrich and activate rhodium by smelting using iron oxide as a trapping agent and activator.A rhodium concentrate was obtained by the separation of base metals and precious metals.The concentrate was reacted with dilute aqua regia to obtain rhodium solution.The factors influencing the enrichment and activation effects were discussed in this paper.The results showed that the dissolution rate is greater than 99％ under the optimum conditions.In this process,the activation of rhodium was finished in the enrichment process.The iron oxide is both a trapping agent and activator,which simplifies the process and reduce the cost.

Fabrication of tubed functionally graded material by slurry dipping process. Thickness control of dip-coated layer

International Nuclear Information System (INIS)

Watanabe, Ryuzo

1997-03-01

In order to obtain long life fuel cladding tubes for the fast breeder reactor, the concept of functionally graded material was applied for the material combination of Molybdenum/stainless steel/Titanium, in which Titanium and Molybdenum were placed at the inner and outer sides, respectively. Slurry dipping method was employed because of its capability of shape forming and microstructural control. We have hitherto reported the design criteria for the graded layers, preparation of the slurry, and microstructural control of the dip-coated layers. In the present report, the thickness control of the dip-coated layer is described in detail. The thickness of the dip-coated layer depends primarily on the viscosity of the slurry. Nevertheless, for the stable dispersion of the powder in the slurry, which dominates the microstructural homogeneity, an optimum viscosity value is present for the individual slurries. With stable slurries of Ti, Mo, stainless steel powders and their mixtures, the thicknesses of dip-coated layers were controlled in dependence of their viscosities and yield values. For Ti and stainless steel powders and their mixture a PAANa was used as a dispersing agent. A NaHMP was found to be effective for the dispersion of Mo powder and Mo/stainless steel powder mixture. For all slurries tested in the present investigation PVA addition was helpful for the viscosity control. Dip-coating maps have been drawn for the stabilization of the slurries and for the formation of films with a sufficient strength for further manipulation for the slurries with low viscosity (∼10 mPa s). The final film thickness for the low-viscosity slurry with the optimum condition was about 200 μm. The slurries with high viscosities of several hundreds mPa s had a good stability and the yield value was easy to be controlled. The film thickness was able to be adjusted in the size range between several tens and several hundreds μm. The final thickness of the graded layer was determined

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

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhong-Min, E-mail: wangzhongm@xaut.edu.cn; Liu, Yan-Zhuang

2016-03-15

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.

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.

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.

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

Nonlinear analysis of thermally and electrically actuated functionally graded material microbeam.

Science.gov (United States)

Li, Yingli; Meguid, S A; Fu, Yiming; Xu, Daolin

2014-02-08

In this paper, we provide a unified and self-consistent treatment of a functionally graded material (FGM) microbeam with varying thermal conductivity subjected to non-uniform or uniform temperature field. Specifically, it is our objective to determine the effect of the microscopic size of the beam, the electrostatic gap, the temperature field and material property on the pull-in voltage of the microbeam under different boundary conditions. The non-uniform temperature field is obtained by integrating the steady-state heat conduction equation. The governing equations account for the microbeam size by introducing an internal material length-scale parameter that is based on the modified couple stress theory. Furthermore, it takes into account Casimir and van der Waals forces, and the associated electrostatic force with the first-order fringing field effects. The resulting nonlinear differential equations were converted to a coupled system of algebraic equations using the differential quadrature method. The outcome of our work shows the dramatic effect and dependence of the pull-in voltage of the FGM microbeam upon the temperature field, its gradient for a given boundary condition. Specifically, both uniform and non-uniform thermal loading can actuate the FGM microbeam even without an applied voltage. Our work also reveals that the non-uniform temperature field is more effective than the uniform temperature field in actuating a FGM cantilever-type microbeam. For the clamped-clamped case, care must be taken to account for the effective use of thermal loading in the design of microbeams. It is also observed that uniform thermal loading will lead to a reduction in the pull-in voltage of a FGM microbeam for all the three boundary conditions considered.

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.

Comparison of the reliability of two hydronephrosis grading systems: The Society for Foetal Urology grading system vs. the Onen grading system

International Nuclear Information System (INIS)

Kim, S.-Y.; Kim, M.-J.; Yoon, C.S.; Lee, M.S.; Han, K.H.; Lee, M.-J.

2013-01-01

Aim: To compare the reliability of the conventional ultrasonography grading system for hydronephrosis as suggested by the Society for Fetal Urology (SFU) in 1993 and that developed by Onen in 2007. Materials and methods: One hundred and eighty kidneys in 90 paediatric patients were assessed by four radiologists using each of the two grading systems twice. The SFU system was graded 0–4 (0 = no hydronephrosis; 1 = visualized only renal pelvis; 2 = plus a few caliceal dilatation; 3 = all calyceal dilatation; 4 = plus parenchymal thinning). The Onen system was graded 0–4 (0 = no hydronephrosis; 1 = only renal pelvic dilatation; 2 = plus caliceal dilatation; 3 = plus 50% renal parenchymal loss). Cohen's kappa statistic was used to estimate intra- and interobserver agreement. The weighted least-squares approach was used to compare the intra-observer agreement, and bootstrapping was used to compare the interobserver agreement between the two systems. Results: Intra-observer agreement was substantial to almost perfect in both the SFU (κ 0.79–0.95) and the Onen (κ 0.66–0.97) grading system without difference. The overall interobserver agreement was substantial in both the SFU (κ 0.61–0.68) and the Onen (κ 0.66–0.76) grading system. However, interobserver agreement was fair to moderate for SFU grades 1 and 2 and Onen grades 2 and 3. Conclusion: Both the SFU and Onen grading system are reliable with good intra- and interobserver agreement. However, decreased interobserver agreement was demonstrated for SFU grades 1 and 2 and Onen grades 2 and 3

Analysis of material flow in a utillzation technology of low grade manganese ore and sulphur coal complementary

Science.gov (United States)

Wang, Bo-Zhi; Deng, Biao; Su, Shi-Jun; Ding, Sang-Lan; Sun, Wei-Yi

2018-03-01

Electrolytic manganese is conventionally produced through low-grade manganese ore leaching in SO2, with the combustion of high sulfur coal. Subsequently the coal ash and manganese slag, produced by the combustion of high sulfur coal and preparation of electrolytic manganese, can be used as raw ingredients for the preparation of sulphoaluminate cement. In order to realize the `coal-electricity-sulfur-manganese-building material' system of complementary resource utilization, the conditions of material inflow and outflow in each process were determined using material flow analysis. The material flow models in each unit and process can be obtained by analyzed of material flow for new technology, and the input-output model could be obtained. Through the model, it is possible to obtain the quantity of all the input and output material in the condition of limiting the quantity of a substance. Taking one ton electrolytic manganese as a basis, the quantity of other input material and cements can be determined with the input-output model. The whole system had thusly achieved a cleaner production level. Therefore, the input-output model can be used for guidance in practical production.

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…

Design optimization of cementless metal-backed cup prostheses using the concept of functionally graded material

Energy Technology Data Exchange (ETDEWEB)

Hedia, H S; El-Midany, T T; Shabara, M A N; Fouda, N [Production Engineering and M/C Design Department, Faculty of Engineering, Mansoura University, Mansoura (Egypt)

2006-09-15

Metal backing has been widely used in acetabular cup design. A stiff backing for a polyethylene liner was initially believed to be mechanically favourable. Yet, recent studies of the load transfer around acetabular cups have shown that a stiff backing causes two problems. It generates higher stress peaks around the acetabular rim than those caused by full polyethylene cups and reduces the stresses transferred to the dome of the acetabulum causing stress shielding. The aim of this study is to overcome these two problems by improving the design of cementless metal-backed acetabular cups using the two-dimensional functionally graded material (FGM) concept through finite-element analysis and optimization techniques. It is found that the optimal 2D FGM model must have three bioactive materials of hydroxyapatite, Bioglass and collagen. This optimal material reduces the stress shielding at the dome of the acetabulum by 40% and 37% compared with stainless steel and titanium metal backing shells, respectively. In addition, using the 2D FGM model reduces the maximum interface shear stress in the bone by 31% compared to the titanium metal backing shell.

Strand I: Physical Health Nutrition. Health Curriculum Materials. Grades 4-6.

Science.gov (United States)

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

GRADES OR AGES: Grades 4-6. SUBJECT MATTER: Physical health and nutrition. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into five sections: factors determining what people eat, the role of food in growth and development, the uses of nutrients in food, selection of foods to meet bodily needs, and food in the history of man. The…

Dynamic fracture toughness of ASME SA508 Class 2a ASME SA533 grade A Class 2 base and heat affected zone material and applicable weld metals

International Nuclear Information System (INIS)

Logsdon, W.A.; Begley, J.A.; Gottshall, C.L.

1978-03-01

The ASME Boiler and Pressure Vessel Code, Section III, Article G-2000, requires that dynamic fracture toughness data be developed for materials with specified minimum yield strengths greater than 50 ksi to provide verification and utilization of the ASME specified minimum reference toughness K/sub IR/ curve. In order to qualify ASME SA508 Class 2a and ASME SA533 Grade A Class 2 pressure vessel steels (minimum yield strengths equal 65 kip/in. 2 and 70 kip/in. 2 , respectively) per this requirement, dynamic fracture toughness tests were performed on these materials. All dynamic fracture toughness values of SA508 Class 2a base and HAZ material, SA533 Grade A Class 2 base and HAZ material, and applicable weld metals exceeded the ASME specified minimum reference toughness K/sub IR/ curve

7 CFR 52.1855 - Grades of Sultana raisins.

Science.gov (United States)

2010-01-01

... § 52.1855 Grades of Sultana raisins. (a) “U.S. Grade A” is the quality of Sultana Raisins that have... in Table IV of this subpart. (b) “U.S. Grade B” is the quality of Sultana Raisins that have similar... than materially affected. Grit, sand, or silt None of any consequence may be present that affects the...

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.

STRUCTURAL OPTIMIZATION OF FUNCTIONALLY GRADED MATERIALS WITH SMALL CONCENTRATION OF INCLUSIONS

Directory of Open Access Journals (Sweden)

DISKOVSKY A. A.

2017-01-01

Full Text Available Raising of problem.With an optimal design of inner structure of functionally graded material (FGM based on the classical method of homogenization procedure, in cases of low concentration of inclusions, when the size of inclusions is essentially less than the distance between them, leads to computational difficulties. Purpose – the research to develop a homogenization procedure, allowing solving effectively the problem of optimizing the internal structure of FGM at low concentrations of inclusions and illustration with specific examples. Conclusion. The proposed method allows solving tasks of calculation and optimal design of the internal structure of FGM structures with variable inclusions and with a variable step between them using the same methodology. The optimization is performed using two mechanisms. The first allocation is fixed at the edges of the border areas in which inclusions are absent. The second optimization mechanism is the distribution of inclusions sizes under the law, coinciding with the distribution law of an external load. Alternate step for the step should be reduced in areas with greater intensity of the external load.

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.

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.

Functionally Graded Adhesives for Composite Joints

Science.gov (United States)

Stapleton, Scott E.; Waas, Anthony M.; Arnold, Steven M.

2012-01-01

Adhesives with functionally graded material properties are being considered for use in adhesively bonded joints to reduce the peel stress concentrations located near adherend discontinuities. Several practical concerns impede the actual use of such adhesives. These include increased manufacturing complications, alterations to the grading due to adhesive flow during manufacturing, and whether changing the loading conditions significantly impact the effectiveness of the grading. An analytical study is conducted to address these three concerns. An enhanced joint finite element, which uses an analytical formulation to obtain exact shape functions, is used to model the joint. Furthermore, proof of concept testing is conducted to show the potential advantages of functionally graded adhesives. In this study, grading is achieved by strategically placing glass beads within the adhesive layer at different densities along the joint.

Graded/Gradient Porous Biomaterials

Directory of Open Access Journals (Sweden)

Xigeng Miao

2009-12-01

Full Text Available Biomaterials include bioceramics, biometals, biopolymers and biocomposites and they play important roles in the replacement and regeneration of human tissues. However, dense bioceramics and dense biometals pose the problem of stress shielding due to their high Young’s moduli compared to those of bones. On the other hand, porous biomaterials exhibit the potential of bone ingrowth, which will depend on porous parameters such as pore size, pore interconnectivity, and porosity. Unfortunately, a highly porous biomaterial results in poor mechanical properties. To optimise the mechanical and the biological properties, porous biomaterials with graded/gradient porosity, pores size, and/or composition have been developed. Graded/gradient porous biomaterials have many advantages over graded/gradient dense biomaterials and uniform or homogenous porous biomaterials. The internal pore surfaces of graded/gradient porous biomaterials can be modified with organic, inorganic, or biological coatings and the internal pores themselves can also be filled with biocompatible and biodegradable materials or living cells. However, graded/gradient porous biomaterials are generally more difficult to fabricate than uniform or homogenous porous biomaterials. With the development of cost-effective processing techniques, graded/gradient porous biomaterials can find wide applications in bone defect filling, implant fixation, bone replacement, drug delivery, and tissue engineering.

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.

Potential of Reinforced Indonesian Glulam Beams Using Grade I (Bengkirai, Grade II (Kamper, Grade III (Nyatoh Woods for Use in Structural Wood Design

Directory of Open Access Journals (Sweden)

Saptahari Sugiri

2016-05-01

Full Text Available Wood is a natural resource that is renewable and available in various species in tropical countries. Its abundancy in nature makes it easy to obtain, thus making it a nature friendly material for use in construction. Indonesia is the most important source of tropical wood in the world after Brazil, making the use of wood for structural elements very desirable. It is estimated that 4000 different varieties of wood exist in Indonesia. This estimate is based on the herbarium species collected by the Forestry Research Institute, currently counting nearly 4000 types of trees with a diameter of more than 40 cm. In the Indonesian wood structure code, the strength of woods is divided into 3 grades (grade I, II and III. This paper presents an evaluation of the mechanical properties of glulam wood sourced from native Indonesian timber: Bengkirai wood (grade I, Kamper wood (grade II, and Nyatoh wood (grade III, thus proving the potential for Indonesian wood as industrial structural elements in wooden constructions.

Low grade heat driven adsorption system for cooling and power generation using advanced adsorbent materials

International Nuclear Information System (INIS)

Al-Mousawi, Fadhel Noraldeen; Al-Dadah, Raya; Mahmoud, Saad

2016-01-01

Highlights: • Adsorption system based on water and advanced physical adsorbents has the potential of producing cooling and power. • Adding an expander to physisorption system enhances efficiency by up to 11%. • MIL101Cr MOF can produce 95 W/kg and 1357 W/kg of specific power and cooling. • AQSOA Z02 can produce 73 W/kg and 640 W/kg of specific power and cooling. - Abstract: Globally there is abundance of low grade heat sources (around 150 °C) from renewables like solar energy or from industrial waste heat. The exploitation of such low grade heat sources will reduce fossil fuel consumption and CO_2 emissions. Adsorption technology offers the potential of using such low grade heat to generate cooling and power. In this work, the effect of using advanced adsorbent materials like AQSOA-Z02 (SAPO-34) zeolite and MIL101Cr Metal Organic Framework (MOF) at various operating conditions on power and cooling performance compared to that of commonly used silica-gel was investigated using water as refrigerant. A mathematical model for a two bed adsorption cooling cycle has been developed with the cycle modified to produce power by incorporating an expander between the desorber and the condenser. Results show that it is possible to produce power and cooling at the same time without affecting the cooling output. Results also show that for all adsorbents used as the heat source temperature increases, the cooling effect and power generated increase. As for increasing the cold bed temperature, this will decrease the cooling effect and power output except for SAPO-34 which shows slightly increasing trend of cooling and power output. As the condenser cooling temperature increases, the cooling effect and power output will decrease while for the chilled water temperature, the cooling load and power generated increased as the temperature increased. The maximum values of average specific power generation (SP), specific cooling power (SCP) and cycle efficiency are 73 W

Application of the Materials-by-Design Methodology to Redesign a New Grade of the High-Strength Low-Alloy Class of Steels with Improved Mechanical Properties and Processability

Science.gov (United States)

Grujicic, M.; Snipes, J. S.; Ramaswami, S.

2016-01-01

An alternative to the traditional trial-and-error empirical approach for the development of new materials is the so-called materials-by-design approach. Within the latter approach, a material is treated as a complex system and its design and optimization is carried out by employing computer-aided engineering analyses, predictive tools, and available material databases. In the present work, the materials-by-design approach is utilized to redesign a grade of high-strength low-alloy (HSLA) class of steels with improved mechanical properties (primarily strength and fracture toughness), processability (e.g., castability, hot formability, and weldability), and corrosion resistance. Toward that end, a number of material thermodynamics, kinetics of phase transformations, and physics of deformation and fracture computational models and databases have been developed/assembled and utilized within a multi-disciplinary, two-level material-by-design optimization scheme. To validate the models, their prediction is compared against the experimental results for the related steel HSLA100. Then the optimization procedure is employed to determine the optimal chemical composition and the tempering schedule for a newly designed grade of the HSLA class of steels with enhanced mechanical properties, processability, and corrosion resistance.

Thermoelastic Theory for the Response of Materials Functionally Graded in Two Directions with Applications to the Free-Edge Problem

Science.gov (United States)

Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, Steven M.

1995-01-01

A recently developed micromechanical theory for the thermoelastic response of functionally graded composites with nonuniform fiber spacing in the through-thickness direction is further extended to enable analysis of material architectures characterized by arbitrarily nonuniform fiber spacing in two directions. In contrast to currently employed micromechanical approaches applied to functionally graded materials, which decouple the local and global effects by assuming the existence of a representative volume element at every point within the composite, the new theory explicitly couples the local and global effects. The analytical development is based on volumetric averaging of the various field quantities, together with imposition of boundary and interfacial conditions in an average sense. Results are presented that illustrate the capability of the derived theory to capture local stress gradients at the free edge of a laminated composite plate due to the application of a uniform temperature change. It is further shown that it is possible to reduce the magnitude of these stress concentrations by a proper management of the microstructure of the composite plies near the free edge. Thus by an appropriate tailoring of the microstructure it is possible to reduce or prevent the likelihood of delamination at free edges of standard composite laminates.

Low grade uranium ores as potential sources of raw material

International Nuclear Information System (INIS)

Venzlaff, H.

1976-01-01

Reports on the uranium requirement and the uranium reserves show that, even if the demand were to be stretched out slightly, the rate of new discoveries of uranium would have to be doubled or even tripled within a few years in order to ensure supply. Despite some spectacular discoveries of large scale deposits in Australia it must be said that only very few truly new uranium provinces have been discovered over the past twenty years. In this situation more attention is now being devoted to low grade uranium depositis, to findings whose concentration does not exceed 1,000 ppm. These deposits contain quantities of uranium many times larger than the deposits that can now be mined at prices up to 30/lb of U 3 O 8 . Even now low grade uranium ore is being mined as a byproduct, with the actual valuable mineral producing most of the income from mining activities. However, if one strikes a balance in this situation, one finds that only part of the requirement can be met in this way. Hence, all possibilities must be exhausted to mine uranium as a byproduct, new techniques of uranium production from low grade ores must be developed, and also conventional prospection must be intensified, if the continuity of supply of the nuclear power stations in the eighties and nineties is to be guaranteed. (orig.) [de

Analysis of students’ incorrect answers at triangle materials in the fifth-grade of primary school

Science.gov (United States)

Shintawati, E.; Jupri, Al

2018-05-01

This research aims to analyse the comparison of the predictions made by the author between learning methods with the reality that occur in the class and to analyse students' responses toward questions given by teachers at triangle materials. The method used in this research is the descriptive-qualitative method. The subjects of this research are all fifth-grade students from a primary school in the city of Bandung. The results of this research indicated that there are some influences between learning methods and students' responses shown by the way students answer the question. In reality, there are many students’ responses produced beyond the predictions of the author. It shows that as the good teachers, besides setting up learning methods, they should also make predictions toward the responses of the students in answering the questions given. The results of the predictions could be used as a lesson for teachers to run the learning processes as good as possible so the students' responses could being accordance with the concept of materials presented and could also achieve the expected learning goals. Based on this research’s results, as a teacher must have techniques and strategies to overcome things that are not expected during the learning so that learning can be conducive so that students can focus on learning and enjoy learning so that learning outcomes is the ability of students to increase in understanding the material and can construct the concept of material provided.

Kinder Lernen Deutsch Materials Evaluation Project: Grades K-8.

Science.gov (United States)

American Association of Teachers of German.

The Kinder Lernen Deutsch (Children Learn German) project, begun in 1987, is designed to promote German as a second language in grades K-8. The project is premised on the idea that the German program will contribute to the total development of the child and the child's personality. Included in this guide are a selection of recommended core…

Revisions of the Learning Mastery Systems for the Harper and Row Grades One and Two and the Macmillan Bank Street Grade One Reading Series.

Science.gov (United States)

Maeder, Jacqueline; And Others

The revisions on the Learning Mastery Systems (LMSs) for the Harper & Row grade-one and grade-two and the Macmillan Bank Street grade-one reading programs are outlined in this document. A rationale for the revisions is presented. An LMS is a set of materials and procedures prepared by the southwest Regional Laboratory (SWRL) as an…

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)

Development of Bi-Sb-Te ternary alloy with compositionally graded structure

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, A; Ohta, T

1997-07-01

Compositionally graded p-type Bi-Sb-Te thermoelectric material was synthesized by PIES (Pulverized and Intermixed Elements Sintering) method. The materials consisted of three segmented regions of different alloy composition, i.e., y = 0.8/0.825/0.9 in (Bi{sub 2}Te{sub 3}){sub 1{minus}y} (Sb{sub 2}Te{sub 3}){sub y} system. It was found that the electrical power output of the compositionally graded material was larger than that of the best single composition material when the temperature difference was the designed value.

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.

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...

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.

Wear resistance and electrical properties of functionally graded epoxy-resin/silica composites

International Nuclear Information System (INIS)

Rihan, Y. A.; Abd El-Bary, B.

2012-12-01

In this paper graded Silica/Epoxy composite fabricated by controlled mold filling to obtain a stepwise graded structure. The generated graded structure was controlled by the w 1% content of silica particulates of size range from (45 μm-250 μm). Microstructural characterization was conducted using Scanning Electron Microscope (SEM). Electrical properties were conducted in High Voltage-Lab using Sphere-Plate Electrode System and Insulating resistance equipment s. Wear characteristics were studied using Block-on-Ring wear testing machine for the different layers of the graded silica/epoxy composites, The prepared materials are used as coating materials for the floors of chemical laboratories. (Author)

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.

Commercial-grade motors in safety-related applications: Final report

International Nuclear Information System (INIS)

Holzman, P.M.

1988-04-01

The objective of this project was to discuss the process necessary to utilize commercial grade equipment in safety related applications and to provide utilities with guidance for accepting commercial grade motors for safety-related applications. The generic commercial-grade concepts presented in this report can be successfully applied to motors. Commercial grade item utilization has the greatest applicability to motors in ''mild'' environments, because these motors are essentially similar to commercial grade motors in materials, construction methods, and capabilities. The acceptance process is less applicable to motors that are subject to ''harsh'' environments during postulated accidents, because of the unique design features and testing required to qualify these motors

Role of cytologic grading in prognostication of invasive breast carcinoma

Directory of Open Access Journals (Sweden)

Khan Nazoora

2009-01-01

Full Text Available Background: Evaluation of cytologic features is indispensable in the preoperative diagnosis and grading of infiltrating ductal breast carcinoma (CA in fine-needle aspiration cytology (FNAC material and this method can also provide additional information regarding intrinsic features of the tumor as well as its prognosis. Aim: This study has been done to evaluate comparatively the cytologic and histomorphologic grading of infiltrating ductal carcinoma of breast with specific reference to lymph node metastasis and its role in prognostication. Materials and Methods: Forty three patients who underwent FNAC and mastectomy for infiltrating ductal carcinoma were cytologically and histologically graded (employing Robinson′s cytologic grading system and Elston′s modification of Bloom-Richardson system, respectively. Statistical analysis was done employing ′z′ test and c2 test to compare the two grading system and to examine the degree of correlation between the cytologic and histologic grades. Multiple regression analysis was done to assess the significance of every cytologic and histologic parameter. All 43 cases, graded cyto-histologically were also evaluated for presence or absence of metastasis to the regional lymph nodes employing c2 test. Results: With histologic grade taken as the standard, cytology was found to be fairly comparable, for grading breast carcinoma (overall sensitivity 89.1%, specificity 100%. Further comparison of the two grading systems by Z-test showed that difference between the cytologic and histologic grading was insignificant in all the three grade (p > 0.05. Of the six parameters studied, cell dissociation, nucleoli and chromatin pattern were the most influential features (p < 0.001. The statistically significant difference (p < 0.001 was found in incidences of axillary lymph node metastatic rate in three cytologic grades (15.4% in grade I vs. 83.3% in grade III as well. Conclusions: Apart from being simple and

Comparison of Crack Growth Test Results at Elevated Temperature and Design Code Material Properties for Grade 91 Steel

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyeong-Yeon; Kim, Woo-Gon; Kim, Nak-Hyun [Korea Atomic Energy Reserach Institute, Daejeon (Korea, Republic of)

2015-01-15

The material properties of crack growth models at an elevated temperature were derived from the results of numerous crack growth tests for Mod.9Cr-1Mo (ASME Grade 91) steel specimens under fatigue loading and creep loading at an elevated temperature. These crack growth models were needed for defect assessment under creep-fatigue loading. The mathematical crack growth rate models for fatigue crack growth (FCG) and creep crack growth (CCG) were determined based on the test results, and the models were compared with those of the French design code RCCMRx to investigate the conservatism of the code. The French design code RCC-MRx provides an FCG model and a CCG model for Grade 91 steel in Section III Tome 6. It was shown that the FCG model of RCC-MRx is conservative, while the CCG model is non-conservative compared with the present test data. Thus, it was shown that further validation of the property was required. Mechanical strength tests and creep tests were also conducted, and the test results were compared with those of RCC-MRx.

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.

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.)

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...

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

77 FR 51581 - Request for a License To Export Nuclear Grade Graphite

Science.gov (United States)

2012-08-24

... NUCLEAR REGULATORY COMMISSION Request for a License To Export Nuclear Grade Graphite Pursuant to... 27, 2012, graphite for of nuclear grade graphite to the XMAT424, 11006032. nuclear end use. graphite. Shanghai Institute of Applied Physics in China to test various types of nuclear grade graphite material in...

Typing and grading of cytological category C5 breast lesions

International Nuclear Information System (INIS)

Zafar, N.; Jamal, S.; Mamoon, N.; Luqman, M.; Anwar, M.

2005-01-01

Objective: To determine the tumour type, cytological grade and nuclear grade on fine-needle aspiration smears in cytological category C5 breast lesions and compare them with histopathological findings. Subjects and Methods: Out of all patients referred to AFIP, Rawalpindi for fine-needle aspiration of breast masses, those adjudged C5 (malignant) were chosen for this study. History, clinical details and mammographic findings were noted. Aspirated smears were examined and an attempt was made to ascertain tumour type, cytological grade and nuclear grade. On excision of these lesions, the cytological findings were compared with those on paraffin-embedded histological sections. Results: A total of 71 patients were included in this study. Of these, 64 (90.14%) were cytologically diagnosed as ductal carcinoma, 4 (5.63%) lobular carcinoma, 2 (2.82%) mucinous carcinoma and 1 (1.41%) as medullary carcinoma. Seventy (98.60%) tumours were correctly typed on aspiration smears. Sixty-eight (95.77%) cases were cytologically graded with accuracy. Nuclear grading was even better on cytology and, excluding one malignant lymphoma, all 70 (100%) smears were assessed correctly. Conclusion: Overall efficiency of the tumour typing, cytological grading and nuclear grading on aspirated material turned out to be quite accurate. In expert hands, cytological examination can be of great help in pre-operative planning and in cases where tumour morphology in paraffin-embedded material has been distorted by neo-adjuvant therapy prior to excision. (author)

Fast plasma sintering delivers functional graded materials components with macroporous structures and osseointegration properties.

Science.gov (United States)

Godoy, R F; Coathup, M J; Blunn, G W; Alves, A L; Robotti, P; Goodship, A E

2016-04-13

We explored the osseointegration potential of two macroporous titanium surfaces obtained using fast plasma sintering (FPS): Ti macroporous structures with 400-600 µmØ pores (TiMac400) and 850-1000 µmØ pores (TiMac850). They were compared against two surfaces currently in clinical use: Ti-Growth® and air plasma spray (Ti-Y367). Each surface was tested, once placed over a Ti-alloy and once onto a CoCr bulk substrate. Implants were placed in medial femoral condyles in 24 sheep. Samples were explanted at four and eight weeks after surgery. Push-out loads were measured using a material-testing system. Bone contact and ingrowth were assessed by histomorphometry and SEM and EDX analyses. Histology showed early osseointegration for all the surfaces tested. At 8 weeks, TiMac400, TiMac850 and Ti-Growth® showed deep bone ingrowth and extended colonisation with newly formed bone. The mechanical push-out force was equal in all tested surfaces. Plasma spray surfaces showed greater bone-implant contact and higher level of pores colonisation with new bone than FPS produced surfaces. However, the void pore area in FPS specimens was significantly higher, yet the FPS porous surfaces allowed a deeper osseointegration of bone to implant. FPS manufactured specimens showed similar osseointegration potential to the plasma spray surfaces for orthopaedic implants. FPS is a useful technology for manufacturing macroporous titanium surfaces. Furthermore, its capability to combine two implantable materials, using bulk CoCr with macroporous titanium surfaces, could be of interest as it enables designers to conceive and manufacture innovative components. FPS delivers functional graded materials components with macroporous structures optimised for osseointegration.

Integration of a functionally graded W/Cu transition for divertor components of fusion facilities

International Nuclear Information System (INIS)

Pintsuk, G.

2004-01-01

One of the most difficult topics in the design and development of future fusion devices, e.g. ITER (Latin for ''the way'') is the field of plasma facing components for the divertor. In steady-state mode these will be exposed to heat fluxes up to 20 MW/m 2 . The favored design-option is a component made out of tungsten and copper-alloys. Since these materials differ in their thermal expansion coefficient and their elastic modulus a temperature gradient within the component, caused by thermal loads, results in stresses at the interface. An alternative design-option for divertor-components deals with the insertion of a functionally graded material (FGM) between tungsten and copper. This establishes a continuous change of material properties and therefore minimize the stresses and optimize the thermal behavior of the component. Low pressure plasma-spraying and direct laser-sintering are introduced as possible production-methods of graded W/Cu-composites. Based on preliminary investigations both are used for fabricating W/Cu-composite materials with different mixing ratios. Thermo-mechanical and thermo-physical material properties will be determined on these composites and extrapolated to all mixing ratios. For laser-sintering these are limited to Cu-contents of ∝20 to 100 Vol%. Therefore the plasma-spraying process is favored. In finite-element-analyses the graded material and its material properties will be implemented into a 2-D simulation-model of a divertor component. The composition and the design of the graded W/Cu-composite will be optimized. Best results are obtained by high contents of tungsten within the graded layer, which are still improved by a macro-brush design with dimensions of 4.5 x 4.5 mm 2 . This results in a transfer of critical stresses from the mechanical bonded interface between the plasma facing and the graded material to the diffusion bonded interface between the graded material and copper. The joining of tungsten, a plasma-sprayed graded W

Consumer Law-Related Education Materials (Grades 4-7). Okeechobee County.

Science.gov (United States)

Allen, Rodney F., Ed.; Landry, Russell H., Ed.

These teacher-developed learning activities for grades 4-7 deal with consumer law-related topics. The self-contained activities are organized into five sections. Section one contains a role-playing card game that helps students examine rules and feelings. For example, one role-playing situation involves a confrontation between a student and a bus…

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.

Production of nuclear grade zirconium: A review

Energy Technology Data Exchange (ETDEWEB)

Xu, L., E-mail: L.Xu-2@tudelft.nl [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110004 (China); Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD (Netherlands); Xiao, Y. [Department of Metallurgical Engineering, Anhui University of Technology, Ma' anshan 243002 (China); Zr-Hf-Ti Metallurgie B.V., Den Haag 2582 SB (Netherlands); Sandwijk, A. van [Zr-Hf-Ti Metallurgie B.V., Den Haag 2582 SB (Netherlands); Xu, Q. [School of Materials Science and Metallurgy, Northeastern University, Shenyang 110004 (China); Yang, Y. [Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD (Netherlands)

2015-11-15

Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium as a fuel cladding material. This paper provides an overview of the processes for nuclear grade zirconium production with emphasis on the methods of Zr–Hf separation. The separation processes are roughly classified into hydro- and pyrometallurgical routes. The known pyrometallurgical Zr–Hf separation methods are discussed based on the following reaction features: redox characteristics, volatility, electrochemical properties and molten salt–metal equilibrium. In the present paper, the available Zr–Hf separation technologies are compared. The advantages and disadvantages as well as future directions of research and development for nuclear grade zirconium production are discussed.

Classical entropy generation analysis in cooled homogenous and functionally graded material slabs with variation of internal heat generation with temperature, and convective–radiative boundary conditions

International Nuclear Information System (INIS)

Torabi, Mohsen; Zhang, Kaili

2014-01-01

This article investigates the classical entropy generation in cooled slabs. Two types of materials are assumed for the slab: homogeneous material and FGM (functionally graded material). For the homogeneous material, the thermal conductivity is assumed to be a linear function of temperature, while for the FGM slab the thermal conductivity is modeled to vary in accordance with the rule of mixtures. The boundary conditions are assumed to be convective and radiative concurrently, and the internal heat generation of the slab is a linear function of temperature. Using the DTM (differential transformation method) and resultant temperature fields from the DTM, the local and total entropy generation rates within slabs are derived. The effects of physically applicable parameters such as the thermal conductivity parameter for the homogenous slab, β, the thermal conductivity parameter for the FGM slab, γ, gradient index, j, internal heat generation parameter, Q, Biot number at the right side, Nc 2 , conduction–radiation parameter, Nr 2 , dimensionless convection sink temperature, δ, and dimensionless radiation sink temperature, η, on the local and total entropy generation rates are illustrated and explained. The results demonstrate that considering temperature- or coordinate-dependent thermal conductivity and radiation heat transfer at both sides of the slab have great effects on the entropy generation. - Highlights: • The paper investigates entropy generation in a slab due to heat generation and convective–radiative boundary conditions. • Both homogeneous material and FGM (functionally graded material) were considered. • The calculations are carried out using the differential transformation method which is a well-tested analytical technique

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.

Leveraging comprehensive baseline datasets to quantify property variability in nuclear-grade graphites

Energy Technology Data Exchange (ETDEWEB)

Carroll, Mark C., E-mail: mark.carroll@inl.gov [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2213 (United States); Windes, William E.; Rohrbaugh, David T. [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2213 (United States); Strizak, Joseph P.; Burchell, Timothy D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6088 (United States)

2016-10-15

Highlights: • An effort is underway to fully quantify the properties of nuclear-grade graphites. • Physical and mechanical properties of graphite are best characterized by distributions. • The Weibull distribution is most representative of graphite based on goodness-of-fit. • Fine-grained isomolded grades exhibit higher Weibull modulus values, indicative of more homogeneous properties. - Abstract: The full characterization of the physical and mechanical properties of candidate nuclear-grade graphites is highly dependent upon an understanding of the distribution of values that are inherent to graphite. Not only do the material properties of graphites vary considerably between grades owing to the raw materials sources, filler particle type and size, methods of compaction, and production process parameters, but variability is observed between billets of the same grade from a single batch and even across spatial positions within a single billet. Properly enveloping the expected properties of interest requires both a substantial amount of data to statistically capture this variability and a representative distribution capable of accurately describing the range of values. A two-parameter Weibull distribution is confirmed to be representative of the distribution of physical (density, modulus) and mechanical (compressive, flexure, and tensile strength) values in five different nuclear-grades of graphite. The fine-grained isomolded grades tend toward higher Weibull modulus and characteristic strength values, while the extruded grade being examined exhibits relatively large distributions in property values. With the number of candidate graphite specimens that can undergo full irradiation exposure and subsequent testing having limited feasibility with regard to economics and timely evaluations, a proper capture of the raw material variability in an unirradiated state can provide crucial supplementary resolution to the limited amount of available data on irradiated

INAA of polyacrylic hydrogels of pharmaceutical grade

International Nuclear Information System (INIS)

Ponta, C.; Salagean, M.; Pantelica, A.; Georgescu, I.I.

1998-01-01

Polyacrylic acid (PA) and its salts are promising biomaterials used in the pharmaceutical industry. They could be used as pharmaceutical additives, as a burn dressing and also in the slow released implants or trans-derma patch formulations. Polyacrylic acid of pharmaceutical grade can be obtained by gamma irradiation polymerization. The influence of the raw materials and of the technological procedure on the final product purity has been investigated by Instrumental Neutron Activation Analysis (INAA) method. The following materials have been analyzed by INAA: 1) acrylic acid of technical grade; 2) acrylic acid purified by double crystallisation; 3) NaOH of analytical grade; 4) CaCl-2·6H 2 O of pharmaceutical grade; 5) CaCl 2 ·2H 2 O of analytical grade; 6) granulated PANa; 7) ungranulated PANa; 8) ungranulated PANaCa; 9) PANaCa granulated by milling in IFIN-HH using the mill nr. 1; 10) PANaCa granulated by milling in Institute of Chemical and Pharmaceutical Research (ICPR); 11) PANaCa granulated by milling in IFIN-HH using the mill nr. 2. The first five samples, marked from 1 to 5, are raw materials and the other six samples, marked from 6 to 11, are the final polyacrylic structures processed by various technological procedures. The samples together with the appropriate reference materials have been irradiated at WWR-S reactor in a neutron flux of 2.5·10 12 cm -2 s -1 and the induced radioactivity was registered by a HPGe detector (EG/G ORTEC) of 30% efficiency and 2.1 keV resolution. The concentrations of As, Br, Ce, Co, Cr, Fe, La, Sb, Sc, Zn have been determined. For the final polyacrylic structures, except for granulated PANa (sample 6), only the elements Co, Cr, Fe, Sc, Zn were found at the following concentration levels: tens of ppm (Co), ppm (Zn), hundreds of ppb (Cr), tens of ppb (Co), ppb (Co, Sc), 10 -1 ppb (Sc). In the granulated PANa, in comparison with the other analyzed final products, similar concentration values were found for Fe, Sc and Zn

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.

Design and Fabrication of Al2O3-(W, TiC-TiN-Mo-Ni Nano-composite Cermet Tool Materials with Graded Structures

Directory of Open Access Journals (Sweden)

NI Xiu-ying

2018-02-01

Full Text Available Based on the analysis on temperature and stress distributions, as well as fatigue crack propagation in cutting tools, a model for designing compositional distribution and microstructure with graded characteristics was proposed. The addition of ductile phase and the introduction of the graded structure are beneficial to slow down the fatigue crack propagation rate and improve tool life.Al2O3-(W,TiC-TiN-Mo-Ni nano-composite tool material with graded structures was fabricated via two stage hot pressing sintering process, and the microstructure and mechanical properties were studied. The results show that the surface hardness, fracture toughness of inner layer and bending strength of the cermet with sintered gradient structure reach 19.258GPa, 10.015MPa·m1/2 and 1017.475MPa,respectively.The performance requirements to cutting tools were met. The dimple cleavage and torn edge of the binding phase in the fracture surfaces can be beneficial to the improvement of the fracture toughness and bending strength,so the resistance to fatigue crack propagation of tools is improved.

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....

A Modified Kirchhoff plate theory for Free Vibration analysis of functionally graded material plates using meshfree method

Science.gov (United States)

Nguyen Van Do, Vuong

2018-04-01

In this paper, a modified Kirchhoff theory is presented for free vibration analyses of functionally graded material (FGM) plate based on modified radial point interpolation method (RPIM). The shear deformation effects are taken account into modified theory to ignore the locking phenomenon of thin plates. Due to the proposed refined plate theory, the number of independent unknowns reduces one variable and exists with four degrees of freedom per node. The simulated free vibration results employed by the modified RPIM are compared with the other analytical solutions to verify the effectiveness and the accuracy of the developed mesh-free method. Detail parametric studies of the proposed method are then conducted including the effectiveness of thickness ratio, boundary condition and material inhomogeneity on the sample problems of square plates. Results illustrated that the modified mesh-free RPIM can effectively predict the numerical calculation as compared to the exact solutions. The obtained numerical results are indicated that the proposed method are stable and well accurate prediction to evaluate with other published analyses.

Love-type waves in functionally graded piezoelectric material (FGPM) sandwiched between initially stressed layer and elastic substrate

Science.gov (United States)

Saroj, Pradeep K.; Sahu, S. A.; Chaudhary, S.; Chattopadhyay, A.

2015-10-01

This paper investigates the propagation behavior of Love-type surface waves in three-layered composite structure with initial stress. The composite structure has been taken in such a way that a functionally graded piezoelectric material (FGPM) layer is bonded between initially stressed piezoelectric upper layer and an elastic substrate. Using the method of separation of variables, frequency equation for the considered wave has been established in the form of determinant for electrical open and short cases on free surface. The bisection method iteration technique has been used to find the roots of the dispersion relations which give the modes for electrical open and short cases. The effects of gradient variation of material constant and initial stress on the phase velocity of surface waves are discussed. Dependence of thickness on each parameter of the study has been shown explicitly. Study has been also done to show the existence of cut-off frequency. Graphical representation has been done to exhibit the findings. The obtained results are significant for the investigation and characterization of Love-type waves in FGPM-layered media.

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.)

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

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

Faecal glucocorticoid metabolites and body temperature in Australian merino ewes (Ovis aries) during summer artificial insemination (AI) program

Science.gov (United States)

Sawyer, Gregory; Parisella, Simone

2018-01-01

Reproductive wastage is a key issue for sheep producers, both regionally and globally. The reproductive output of farm animals can be influenced by physiological and environmental factors. Rapid and reliable quantification of physiological stress can provide a useful tool for designing and testing on-farm management interventions to improve farm animal welfare and productivity. In this study, we quantified physiological stress non-invasively using faecal glucocorticoid metabolites-FGMs analysis and body temperature measurements of 15 superovulated donor merino ewes (Ovis aries) during participation in artificial insemination (AI) program conducted during 2015/2016 Australian summer. We hypothesized that low percentage transferable embryos in donor merino ewes will be associated positively with higher body temperature and/or higher FGMs in these ewes. Temperature humidity index (THI) was calculated and found within high thermal stress range during the two AI trials. Overall, results showed none of the factors (ewe ID, AI trial no., THI or FGMs) were significant for reduced percentage transferrable embryos, except ewe body temperature was highly significant (p = 0.014). Within AI trial comparisons showed significant positive associations between higher FGMs and body temperature with reduced transferrable embryos. These results suggest that Australian merino ewes participating in summer AI trials can experience physiological stress. Prolonged activation of the stress endocrine response and high body temperature (e.g. ensued from heat stress) could impact on ewe reproductive output. Therefore, future research should apply minimally invasive physiological tools to gather baseline information on physiological stress in merino sheep to enable the development of new farm-friendly methods of managing stress. PMID:29381759

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...

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

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

Recovery of uranium from low-grade sandstone ores and phosphate rock

Energy Technology Data Exchange (ETDEWEB)

Kennedy, R H [United States Atomic Energy Commission, Washington, D. C. (United States)

1967-06-15

This paper is concerned principally with commercial-scale experience in the United States in the recovery of uranium from low-grade sources. Most of these operations have been conducted by the operators of uranium mills as an alternative to processing normal-grade ores. The operations have been generally limited, therefore, to the treatment of low-grade materials generated in the course of mining normal-grade ores. In some circumstances such materials can be treated by simplified procedures as an attractive source of additional production. The experience gained in uranium recovery from phosphate rock will be treated in some detail. The land pebble phosphate rock of central Florida generally contains about 0.01 to 0.02% U{sub 3}O{sub 8}. While no uranium is being recovered from this source at the present time, it does represent a significant potential source of by-product uranium production because of the large tonnages being mined. (author)

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.

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.

Interference studies with two hospital-grade and two home-grade glucose meters.

Science.gov (United States)

Lyon, Martha E; Baskin, Leland B; Braakman, Sandy; Presti, Steven; Dubois, Jeffrey; Shirey, Terry

2009-10-01

Interference studies of four glucose meters (Nova Biomedical [Waltham, MA] StatStrip [hospital grade], Roche Diagnostics [Indianapolis, IN] Accu-Chek Aviva [home grade], Abbott Diabetes Care [Alameda, CA] Precision FreeStyle Freedom [home grade], and LifeScan [Milpitas, CA] SureStep Flexx [hospital grade]) were evaluated and compared to the clinical laboratory plasma hexokinase reference method (Roche Hitachi 912 chemistry analyzer). These meters were chosen to reflect the continuum of care from hospital to home grade meters commonly seen in North America. Within-run precision was determined using a freshly prepared whole blood sample spiked with concentrated glucose to give three glucose concentrations. Day-to-day precision was evaluated using aqueous control materials supplied by each vendor. Common interferences, including hematocrit, maltose, and ascorbate, were tested alone and in combination with one another on each of the four glucose testing devices at three blood glucose concentrations. Within-run precision for all glucose meters was glucose meters. Ascorbate caused differences (percentage change from a sample without added interfering substances) of >5% with pyrroloquinolinequinone (PQQ)-glucose dehydrogenase-based technologies (Aviva and Freestyle) and the glucose oxidase-based Flexx meter. Maltose strongly affected the PQQ-glucose dehydrogenase-based meter systems. When combinations of interferences (ascorbate, maltose, and hematocrit mixtures) were tested, the extent of the interference was up to 193% (Aviva), 179% (FreeStyle), 25.1% (Flexx), and 5.9% (StatStrip). The interference was most pronounced at low glucose (3.9-4.4 mmol/L). All evaluated glucose meter systems demonstrated varying degrees of interference by hematocrit, ascorbate, and maltose mixtures. PQQ-glucose dehydrogenase-based technologies showed greater susceptibility than glucose oxidase-based systems. However, the modified glucose oxidase-based amperometric method (Nova StatStrip) was

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…

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...

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

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.

Supply of equipment and components, materials of dedicated commercial grade, other services; Suministro de equipos y respuestos. Materiales de grado comercial dedicados. Otros servicios

Energy Technology Data Exchange (ETDEWEB)

Perdices, D.; Perez Medina, E.

2014-10-01

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)

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 (<1% porosity) and porous (approx. 5% porosity) zirconia areas to combine different properties in one component. T3DP opens the door to the AM of further ceramic-based 4D components, such as multi-color, multi-material, or especially, multi-functional components.

ABALONE (HALIOTIS SQUAMATA ANESTHESIA WITH ETHANOL ON GRADING PROCESS

Directory of Open Access Journals (Sweden)

Fanni N.A.

2018-02-01

Full Text Available An abalone is a group of marine molluscs that have high economic value. To increase abalone production, such cultivation needs to be done considering that abalone production still dominating. However, there are still obstacles in the cultivation which is the high mortality rates on the grading process of juvenile abalone. The fatality occurs due to the traditional grading process by gouging abalone to separate abalone that is attached to the substrate. The use of ethanol as an anesthetic material is expected to minimize the mortality and increase the survival rate of abalone. In this study, the use of ethanol by 30 ml/L as an anesthetic material can separate the abalone from its substrate 447.67 seconds faster than the dose of 10 ml/L. However, the 30 ml/L dose also showed the lowest survival rate of 86.67%. The best recovery test is at 10 ml/L with the fastest recovery time of 143.33 seconds which has a high survival rate of 98.33%. The success of anesthesia by using ethanol in this study can also be done in the grading process of abalone seed and can minimize death due to the traditional grading process.

Non-invasive monitoring of adrenocortical activity in captive African Penguin (Spheniscus demersus) by measuring faecal glucocorticoid metabolites.

Science.gov (United States)

Ozella, L; Anfossi, L; Di Nardo, F; Pessani, D

2015-12-01

Measurement of faecal glucocorticoid metabolites (FGMs) has become a useful and widely-accepted method for the non-invasive evaluation of stress in vertebrates. In this study we assessed the adrenocortical activity of five captive African Penguins (Spheniscus demersus) by means of FGM evaluation following a biological stressor, i.e. capture and immobilization. In addition, we detected individual differences in secretion of FGMs during a stage of the normal biological cycle of penguins, namely the breeding period, without any external or induced causes of stress. Our results showed that FGM concentrations peaked 5.5-8h after the induced stress in all birds, and significantly decreased within 30 h. As predictable, the highest peak of FGMs (6591 ng/g) was reached by the youngest penguin, which was at its first experience with the stressor. This peak was 1.8-2.7-fold higher compared to those of the other animals habituated to the stimulus. For the breeding period, our results revealed that the increase in FGMs compared to ordinary levels, and the peaks of FGMs, varied widely depending on the age and mainly on the reproductive state of the animal. The bird which showed the lowest peak (2518 ng/g) was an old male that was not in a reproductive state at the time of the study. Higher FGM increases and peaks were reached by the two birds which were brooding (male: 5552%, 96,631 ng/g; female: 1438%, 22,846 ng/g) and by the youngest bird (1582%, 39,700 ng/g). The impact of the reproductive state on FGM levels was unexpected compared to that produced by the induced stress. The EIA used in this study to measure FGM levels proved to be a reliable tool for assessing individual and biologically-relevant changes in FGM concentrations in African Penguin. Moreover, this method allowed detection of physiological stress during the breeding period, and identification of individual differences in relation to the reproductive status. The increase in FGM levels as a response to capture and

CHARACTERIZATION OF METAL GRADES IN A STOCKPILE OF AN IRON MINE (CASE STUDY- CHOGHART IRON MINE, IRAN

Directory of Open Access Journals (Sweden)

Francesco Tinti

2018-01-01

Full Text Available In any mining operation due to the cut-off grade (economic criteria, materials classify into the ore and waste. The material with grade equal to or higher than the cut-off grade is considered as ore and the material with grade less than the cut-off grade is transported as wastes to the waste dumps. However, because of increasing metal demand, depleting of in situ ore reserves and so the reduction of cut-off grades for many metals, the mentioned waste dumps were considered as valuable ore reserves named stockpiles. In this paper, multivariate geostatistics was used to estimate the iron grades of two stockpiles following the sequential of piling procedures from the main source - the ore deposit - to the piling field. One stockpile is characterized by phosphorous concentration ((P % > 0.6 %, while the other by iron concentration ((Fe %< 50%. Since economic and physical constraints made sampling physically and economically problematic, the grade distribution and variability were estimated on the basis of primary blast-hole data from the main ore body and the mine’s long-term planning policy. A geostatistical model was applied to the excavated part of the iron deposit and the stockpile, by reconstructing ore selection, haulage and piling method. Results were validated through spatial variability of iron and phosphorous concentrations by comparing grade variability (Fe and P with mining and pilling units. This methodology allows characterizing the iron grades within stockpiles without any extra sampling.

Structural and Morphological Difference Between Ti/TiN/TiCN Coatings Grown in Multilayer and Graded Form

International Nuclear Information System (INIS)

Restrepo, E.; Baena, A.; Agudelo, C.; Castillo, H.; Devia, A.; Marino, A.

2006-01-01

Thin films can be grown in super-lattice, multilayers and graded form, having each one advantages and disadvantages. The difference between multilayer and graded coatings is the interface. In multilayers the interface is abrupt and in graded coatings it is diffuse. The interface influences many chemical and physical properties of the materials, and its choice depends on the application. Graded coatings have the advantage of having gradual properties such as thermal expansion coefficient and lattice parameter, avoiding adherence problems due to good match between their component materials. In this work the comparison between some properties of coatings grown as multilayer and graded is performed. The materials are produced using the sputtering DC technique because of its facility to control the deposition parameters and generate a slow growth. The target is a disc of titanium and the samples are made of stainless steel 304. The working gases are argon, nitrogen and methane, which are mixed according to the material to be produced, i.e. Ti layer is grown with argon, the TiN film is produced with a mixture of argon and nitrogen, and the TiCN material is obtained mixing argon, nitrogen and methane. These materials are characterized with AFM in order to determine grain size and with XPS studying the chemical composition and performing depth profiles

Flash glucose monitoring system may benefit children and adolescents with type 1 diabetes during fasting at Ramadan.

Science.gov (United States)

Al-Agha, Abdulmoein E; Kafi, Shahd E; Zain Aldeen, Abdullah M; Khadwardi, Raghdah H

2017-04-01

To assess the benefit of using the flash glucose monitoring system (FGMS) in children and adolescents with type 1 diabetes mellitus (T1DM) during Ramadan fasting. Methods: A prospective pilot study of 51 participants visited the pediatric diabetes clinic at King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia from between June until and July 2016. The FreeStyle® Libre™ FGMS (Abbott Diabetes Care, Alameda, CA, USA) was used. Hypoglycemia was defined as glucose values of less than 70 mg/dL, while hyperglycemia as glucose values of more than 150 mg/dL for all participants based on our institute's protocol. Results: Participants were able to fast for 67.0% of the total days eligible for fasting, whereas they did not fast on 33% of the days due to either hypoglycemia (15.4%) or non-diabetes-related reasons (17.6 %). None of the participants developed severe hypoglycemia. The mean number of hyperglycemic episodes during fasting hours was 1.29, per day, which was higher than that of hypoglycemic episodes (0.7). None of the participants developed diabetic ketoacidosis (DKA). Glycemic control with mean of estimated hemoglobin A1C reading during Ramadan (8.16 ± 1.64% [pre study]) to 8.2 ± 1.63% [post study] p=0.932. Conclusions: Children and adolescents with T1DM who use the FGMS could fast without the risk of life-threatening episodes of severe hypoglycemia (namely seizure, coma), or DKA during Ramadan. Adequate education and good glycemic control prior to Ramadan are important strategies in combination with the use of an FGMS to achieve better outcome.

Flash glucose monitoring system may benefit children and adolescents with type 1 diabetes during fasting at Ramadan

Directory of Open Access Journals (Sweden)

Abdulmoein E. Al-Agha

2017-04-01

Full Text Available Objectives: To assess the benefit of using the flash glucose monitoring system (FGMS in children and adolescents with type 1 diabetes mellitus (T1DM during Ramadan fasting. Methods: A prospective pilot study of 51 participants visited the pediatric diabetes clinic at King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia from between June until and July 2016. The FreeStyle® Libre™ FGMS (Abbott Diabetes Care, Alameda, CA, USA was used. Hypoglycemia was defined as glucose values of less than 70 mg/dL, while hyperglycemia as glucose values of more than 150 mg/dL for all participants based on our institute’s protocol. Results: Participants were able to fast for 67.0% of the total days eligible for fasting, whereas they did not fast on 33% of the days due to either hypoglycemia (15.4% or non-diabetes-related reasons (17.6 %. None of the participants developed severe hypoglycemia. The mean number of hyperglycemic episodes during fasting hours was 1.29, per day, which was higher than that of hypoglycemic episodes (0.7. None of the participants developed diabetic ketoacidosis (DKA. Glycemic control with mean of estimated hemoglobin A1C reading during Ramadan (8.16 ± 1.64% [pre study] to 8.2 ± 1.63% [post study] p=0.932. Conclusions: Children and adolescents with T1DM who use the FGMS could fast without the risk of life-threatening episodes of severe hypoglycemia (namely seizure, coma, or DKA during Ramadan. Adequate education and good glycemic control prior to Ramadan are important strategies in combination with the use of an FGMS to achieve better outcome.

Laboratory study on subgrade soil stabilization using RBI grade 81

Science.gov (United States)

Cynthia, J. Bernadette; Kamalambikai, B.; Prasanna Kumar, R.; Dharini, K.

2017-07-01

The present study investigates the effect of reinforcing the sub grade soils with RBI 81 material. A soil nearby was collected and preliminary tests were conducted to classify the soil and it was found from the results that the sample collected was a poorly graded clay. Subsequently Tests such as Proctor Compaction, CBR, and UCC were conducted to study the various engineering properties of the identified soil. In addition to the above tests were also conducted on the soil by reinforcing with varying percentages of RBI 81. From the analysis of test results it was found that this material (RBI 81) will significantly improve the CBR value of the soil.

Analysis, manufacture and characterization of Ni/Cu functionally graded structures

International Nuclear Information System (INIS)

Rubio, Wilfredo Montealegre; Paulino, Glaucio H.; Silva, Emilio Carlos Nelli

2012-01-01

Highlights: ► Functionally graded structures (FGSs) of nickel and copper can be manufactured. ► The hardness curve of FGS can be used for approximating the gradation function of elastic properties. ► The graded finite element approaches with great accuracy the FGS resonance frequencies obtained experimentally. -- Abstract: In this work, an experimental and numerical analysis and characterization of functionally graded structures (FGSs) is developed. Nickel (Ni) and copper (Cu) materials are used as basic materials in the numerical modeling and experimental characterization. For modeling, a MATLAB finite element code is developed, which allows simulation of harmonic and modal analysis considering the graded finite element formulation. For experimental characterization, Ni–Cu FGSs are manufactured by using spark plasma sintering technique. Hardness and Young’s modulus are found by using microindentation and ultrasonic measurements, respectively. The effective gradation of Ni/Cu FGS is addressed by means of optical microscopy, energy dispersive spectrometry, scanning electron microscopy and hardness testing. For the purpose of comparing modeling and experimental results, the hardness curve, along the gradation direction, is used for identifying the gradation profile; accordingly, the experimental hardness curve is used for approximating the Young’s modulus variation and the graded finite element modeling is used for verification. For the first two resonance frequency values, a difference smaller than 1% between simulated and experimental results is obtained.

Microstructure-property relationships and constitutive response of plastically graded case hardened steels

Science.gov (United States)

Klecka, Michael A.

Case hardened materials, popularly used in many demanding engineering applications such as bearings, gears, and wear/impact surfaces, have high surface hardness and a gradient in material properties (hardness, yield strength, etc.) as a function of depth; therefore, they behave as plastically graded materials. In the current study, two different commercially available case carburized steels along with two through hardened steels are characterized to obtain relationships among the volume fraction of subsurface carbides, indentation hardness, elastic modulus, and yield strength as a function of depth. A variety of methods including microindentation, nanoindentation, ultrasonic measurements, compression testing, rule of mixtures, and upper and lower bound models are used to determine the relationships for elastic modulus and compare the experimental results with model predictions. In addition, the morphology, composition, and properties of the carbide particles are also determined. The gradient in hardness with depth in graded materials is commonly determined using microindentation on the cross-section of the material which contains the gradation in microstructure or composition. In the current study, a novel method is proposed to predict the hardness gradient profile using solely surface indentations at a range of loads. The method does not require the graded material to be sectioned, and has practical utility in the surface heat-treatment industry. For a material with a decreasing gradient in hardness, higher indent loads result in a lower measured hardness due to the influence of the softer subsurface layers. A power-law model is presented which relates the measured surface indentation hardness under increasing load to the subsurface gradient in hardness. A coordinated experimental and numerical study is presented to extract the constitutive response of graded materials, utilizing relationships between hardness, plastic deformation, and strain hardening response

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...

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.

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.

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.

Influence of grade on the reliability of corroding pipelines

International Nuclear Information System (INIS)

Maes, M.A.; Dann, M.; Salama, M.M.

2008-01-01

This paper focuses on a comparative analysis of the reliability associated with the evolution of corrosion between normal and high-strength pipe material. The use of high strength steel grades such as X100 and X120 for high pressure gas pipeline in the arctic is currently being considered. To achieve this objective, a time-dependent reliability analysis using variable Y/T ratios in a multiaxial finite strain analysis of thin-walled pipeline is performed. This analysis allows for the consideration of longitudinal grooves and the presence of companion axial tension and bending loads. Limit states models are developed based on suitable strain hardening models for the ultimate behavior of corroded medium and high strength pipeline material. In an application, the evolution of corrosion is modeled in pipelines of different grades that have been subjected to an internal corrosion inspection after a specified time which allows for a Bayesian updating of long-term corrosion estimates and, hence, the derivation of annual probabilities of failure as a function of time. The effect of grade and Y/T is clearly demonstrated

Investigation of free vibration analysis of functionally graded annular piezoelectric plate using COMSOL

Science.gov (United States)

Sharma, Trivendra Kumar; Parashar, Sandeep Kumar

2018-05-01

In the present age functionally graded piezoelectric materials (FGPM) are increasingly being used as actuators and sensors. In spite of the fact that the piezoelectric coupling coefficient for shear d15 has much higher value in comparison to d31 or d33, it is far less utilized for the applications due to complex nature of the shear induced vibrations. In this work three dimensional free vibration analysis of functionally graded piezoelectric material annular plates with free-free boundary conditions is presented. The annular FGPM plate is polarized along the radial direction while the electric field is applied along the thickness direction inducing flexural vibrations of the plate due to d15 effect of functionally graded piezoelectric materials. The material properties are assumed to have a power law variation along the thickness. COMSOL Multiphysics is used to obtain the natural frequencies and modeshapes. Detailed numerical study is performed to ascertain the effect of variation in power law index and various geometrical parameters. The results presented shall be helpful in optimizing the existing applications and developing the new ones utilizing the FGPM annular plates.

Evaluation of material dispersion using a nanosecond optical pulse radiator.

Science.gov (United States)

Horiguchi, M; Ohmori, Y; Miya, T

1979-07-01

To study the material dispersion effects on graded-index fibers, a method for measuring the material dispersion in optical glass fibers has been developed. Nanosecond pulses in the 0.5-1.7-microm region are generated by a nanosecond optical pulse radiator and grating monochromator. These pulses are injected into a GeO(2)-P(2)0(5)-doped silica graded-index fiber. Relative time delay changes between different wavelengths are used to determine material dispersion, core glass refractive index, material group index, and optimum profile parameter of the graded-index fiber. From the measured data, the optimum profile parameter on the GeO(2)-P(2)O(5)-doped silica graded-index fiber could be estimated to be 1.88 at 1.27 microm of the material dispersion free wavelength region and 1.82 at 1.55 microm of the lowest-loss wavelength region in silica-based optical fiber waveguides.

Plane strain analytical solutions for a functionally graded elastic-plastic pressurized tube

International Nuclear Information System (INIS)

Eraslan, Ahmet N.; Akis, Tolga

2006-01-01

Plane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the tube material are assumed to vary radially according to two parametric parabolic forms. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behaviour. Elastic, partially plastic and fully plastic stress states are investigated. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected significantly by the material nonhomogeneity. Different modes of plasticization may take place unlike the homogeneous case. It is also shown mathematically that the nonhomogeneous elastoplastic solution presented here reduces to that of a homogeneous one by appropriate choice of the material parameters

Strand V: Education for Survival. First Aid and Survival Education. Health Curriculum Materials Grades 10-12.

Science.gov (United States)

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

GRADES OR AGES: Grades 10-12. SUBJECT MATTER: First aid and survival education. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into six sections: transportation of the injured, automobile accidents, conditions resulting from nuclear explosion, chemical warfare, natural catastrophes, and psychological first aid. The publication format…

Design of cost-effective M 25 grade of self compacting concrete

International Nuclear Information System (INIS)

Guru Jawahar, J.; Sashidhar, C.; Ramana Reddy, I.V.; Annie Peter, J.

2013-01-01

Highlights: ► Design of cost-effective M 25 grade of self compacting concrete is done. ► Mechanical properties of SCC compared with M 25 grade of conventional concrete. ► Effect of class F fly ash is studied on the SCC mechanical properties. ► Cost analysis is done between M 25 grade of CC and SCC. ► Recommendation of M 25 grade of SCC for normal building constructions. - Abstract: This investigation is mainly focused on the development of cost-effective normal strength M 25 grade of self compacting concrete (SCC) for the use of normal building constructions. Keeping in view of the normal strength, cost, quality and durability of SCC and greenhouse gas emissions, a combination type of SCC was developed with 35% replacement of cement with class F fly ash. This study recommended a SCC mix with moderate fines to obtain a cost-effective normal strength SCC for the normal building constructions. Studies also revealed that further reduction in fines content in SCC with the same replacement level of fly ash decreased the SCC strength and its performance. Cost analysis has been done between M 25 grade of SCC and conventional concrete (CC). Results shown that the SCC material cost is slightly higher than that of CC of the same strength class, but the savings in labour cost and construction time and quality of SCC would offset the SCC material cost and reduce the total life cycle cost of SCC

Experimental Tape Casting of Adjacently Graded Materials for Magnetic Refrigeration

DEFF Research Database (Denmark)

Bulatova, Regina

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...... of the side-by-side tape casting technique: recognising critical parameters which affect the quality of a graded tape, shape and position of the interface area. Studied parameters can be divided into two categories: operational parameters and slurry formulation optimisation. The operational parameters...

Method of dry distillation of low-grade fuels

Energy Technology Data Exchange (ETDEWEB)

Hellsing, G H; Wengstrom, R O.A.

1920-05-20

A method of dry distillation of low-grade fuels is characterized by having the process take place in a furnace that is charged alternately by partly cooled, red-hot, and fresh raw materials. The patent has one more claim.

Digital fabrication of multi-material biomedical objects

Energy Technology Data Exchange (ETDEWEB)

Cheung, H H; Choi, S H, E-mail: shchoi@hku.h [Department of Industrial and Manufacturing Systems Engineering, University of Hong Kong, Pokfulam Road (Hong Kong)

2009-12-15

This paper describes a multi-material virtual prototyping (MMVP) system for modelling and digital fabrication of discrete and functionally graded multi-material objects for biomedical applications. The MMVP system consists of a DMMVP module, an FGMVP module and a virtual reality (VR) simulation module. The DMMVP module is used to model discrete multi-material (DMM) objects, while the FGMVP module is for functionally graded multi-material (FGM) objects. The VR simulation module integrates these two modules to perform digital fabrication of multi-material objects, which can be subsequently visualized and analysed in a virtual environment to optimize MMLM processes for fabrication of product prototypes. Using the MMVP system, two biomedical objects, including a DMM human spine and an FGM intervertebral disc spacer are modelled and digitally fabricated for visualization and analysis in a VR environment. These studies show that the MMVP system is a practical tool for modelling, visualization, and subsequent fabrication of biomedical objects of discrete and functionally graded multi-materials for biomedical applications. The system may be adapted to control MMLM machines with appropriate hardware for physical fabrication of biomedical objects.

Digital fabrication of multi-material biomedical objects

International Nuclear Information System (INIS)

Cheung, H H; Choi, S H

2009-01-01

This paper describes a multi-material virtual prototyping (MMVP) system for modelling and digital fabrication of discrete and functionally graded multi-material objects for biomedical applications. The MMVP system consists of a DMMVP module, an FGMVP module and a virtual reality (VR) simulation module. The DMMVP module is used to model discrete multi-material (DMM) objects, while the FGMVP module is for functionally graded multi-material (FGM) objects. The VR simulation module integrates these two modules to perform digital fabrication of multi-material objects, which can be subsequently visualized and analysed in a virtual environment to optimize MMLM processes for fabrication of product prototypes. Using the MMVP system, two biomedical objects, including a DMM human spine and an FGM intervertebral disc spacer are modelled and digitally fabricated for visualization and analysis in a VR environment. These studies show that the MMVP system is a practical tool for modelling, visualization, and subsequent fabrication of biomedical objects of discrete and functionally graded multi-materials for biomedical applications. The system may be adapted to control MMLM machines with appropriate hardware for physical fabrication of biomedical objects.

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.

MRI differentiation of low-grade from high-grade appendicular chondrosarcoma

International Nuclear Information System (INIS)

Douis, Hassan; Singh, Leanne; Saifuddin, Asif

2014-01-01

To identify magnetic resonance imaging (MRI) features which differentiate low-grade chondral lesions (atypical cartilaginous tumours/grade 1 chondrosarcoma) from high-grade chondrosarcomas (grade 2, grade 3 and dedifferentiated chondrosarcoma) of the major long bones. We identified all patients treated for central atypical cartilaginous tumours and central chondrosarcoma of major long bones (humerus, femur, tibia) over a 13-year period. The MRI studies were assessed for the following features: bone marrow oedema, soft tissue oedema, bone expansion, cortical thickening, cortical destruction, active periostitis, soft tissue mass and tumour length. The MRI-features were compared with the histopathological tumour grading using univariate, multivariate logistic regression and receiver operating characteristic curve (ROC) analyses. One hundred and seventy-nine tumours were included in this retrospective study. There were 28 atypical cartilaginous tumours, 79 grade 1 chondrosarcomas, 36 grade 2 chondrosarcomas, 13 grade 3 chondrosarcomas and 23 dedifferentiated chondrosarcomas. Multivariate analysis demonstrated that bone expansion (P = 0.001), active periostitis (P = 0.001), soft tissue mass (P < 0.001) and tumour length (P < 0.001) were statistically significant differentiating factors between low-grade and high-grade chondral lesions with an area under the ROC curve of 0.956. On MRI, bone expansion, active periostitis, soft tissue mass and tumour length can reliably differentiate high-grade chondrosarcomas from low-grade chondral lesions of the major long bones. (orig.)

MRI differentiation of low-grade from high-grade appendicular chondrosarcoma

Energy Technology Data Exchange (ETDEWEB)

Douis, Hassan; Singh, Leanne; Saifuddin, Asif [The Royal National Orthopaedic Hospital NHS Trust, Department of Radiology, Stanmore, Middlesex (United Kingdom)

2014-01-15

To identify magnetic resonance imaging (MRI) features which differentiate low-grade chondral lesions (atypical cartilaginous tumours/grade 1 chondrosarcoma) from high-grade chondrosarcomas (grade 2, grade 3 and dedifferentiated chondrosarcoma) of the major long bones. We identified all patients treated for central atypical cartilaginous tumours and central chondrosarcoma of major long bones (humerus, femur, tibia) over a 13-year period. The MRI studies were assessed for the following features: bone marrow oedema, soft tissue oedema, bone expansion, cortical thickening, cortical destruction, active periostitis, soft tissue mass and tumour length. The MRI-features were compared with the histopathological tumour grading using univariate, multivariate logistic regression and receiver operating characteristic curve (ROC) analyses. One hundred and seventy-nine tumours were included in this retrospective study. There were 28 atypical cartilaginous tumours, 79 grade 1 chondrosarcomas, 36 grade 2 chondrosarcomas, 13 grade 3 chondrosarcomas and 23 dedifferentiated chondrosarcomas. Multivariate analysis demonstrated that bone expansion (P = 0.001), active periostitis (P = 0.001), soft tissue mass (P < 0.001) and tumour length (P < 0.001) were statistically significant differentiating factors between low-grade and high-grade chondral lesions with an area under the ROC curve of 0.956. On MRI, bone expansion, active periostitis, soft tissue mass and tumour length can reliably differentiate high-grade chondrosarcomas from low-grade chondral lesions of the major long bones. (orig.)

Numerical simulation of thermal fracture in functionally graded

Indian Academy of Sciences (India)

Numerical simulation of thermal fracture in functionally graded materials using element-free ... Initially, the temperature distribution over the domain is obtained by solving the heat transfer problem. ... Department of Mechanical Engineering, National Institute of Technology, Hamirpur 177005, India ... Contact | Site index.

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...

Optimization of BI test parameters to investigate mechanical properties of Grade 92 steel

Science.gov (United States)

Barbadikar, Dipika R.; Vincent, S.; Ballal, Atul R.; Peshwe, Dilip R.; Mathew, M. D.

2018-04-01

The ball indentation (BI) testing is used to evaluate the tensile properties of materials namely yield strength, strength coefficient, ultimate tensile strength, and strain hardening exponent. The properties evaluated depend on a number of BI test parameters. These parameters include the material constants like yield slope (YS), constraint factor (CF), yield offset parameter (YOP). Number of loading/unloading cycles, preload, indenter size and depth of penetration of indenter also affects the properties. In present investigation the effect of these parameters on the stress-strain curve of normalized and tempered Grade 92 steel is evaluated. Grade 92 is a candidate material for power plant application over austenitic stainless steel and derives its strength from M23C6, MX precipitates and high dislocation density. CF, YS and YOP changed the strength properties considerably. Indenter size effect resulted in higher strength for smaller indenter. It is suggested to use larger indenter diameter and higher number of loading cycles for GRADE 92 steel to get best results using BI technique.

Preparation and characterization of PMMA graded microporous foams via one-step supercritical carbon dioxide foaming

International Nuclear Information System (INIS)

Yuan Huan; Li Junguo; Xiong Yuanlu; Luo Guoqiang; Shen Qiang; Zhang Lianmeng

2013-01-01

Supercritical carbon dioxide (ScCO 2 ) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were foamed by PMMA matrix after an unstable saturation process which was done under supercritical condition of 28MPa and 50 °C. The scanning electron microscopy (SEM) was utilized to observe the morphology of the graded foam. A gas adsorption model was proposed to predict the graded gas concentration in the different region of the polymer matrix. The SEM results showed that the solid and foam region of the graded foam can be connected without laminated layers. With the increasing thickness position of the graded microporous foam, the cell size increased from 3.4 to 27.5 μm, while the cell density decreased from 1.04 × 10 9 to 1.96 × 10 7 cells/cm 3 . It also found that the gradient microporous structure of the foam came from graded gas concentration which was obtained in the initial saturation process.

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).

Readability of Online Patient Education Materials From the AAOS Web Site

Science.gov (United States)

Badarudeen, Sameer; Unes Kunju, Shebna

2008-01-01

One of the goals of the American Academy of Orthopaedic Surgeons (AAOS) is to disseminate patient education materials that suit the readability skills of the patient population. According to standard guidelines from healthcare organizations, the readability of patient education materials should be no higher than the sixth-grade level. We hypothesized the readability level of patient education materials available on the AAOS Web site would be higher than the recommended grade level, regardless when the material was available online. Readability scores of all articles from the AAOS Internet-based patient information Web site, “Your Orthopaedic Connection,” were determined using the Flesch-Kincaid grade formula. The mean Flesch-Kincaid grade level of the 426 unique articles was 10.43. Only 10 (2%) of the articles had the recommended readability level of sixth grade or lower. The readability of the articles did not change with time. Our findings suggest the majority of the patient education materials available on the AAOS Web site had readability scores that may be too difficult for comprehension by a substantial portion of the patient population. PMID:18324452

Differentiation between grade 3 and grade 4 articular cartilage defects of the knee: Fat-suppressed proton density-weighted versus fat-suppressed three-dimensional gradient-echo MRI

Energy Technology Data Exchange (ETDEWEB)

Lee, So Yeon; Jee, Won-Hee; Kim, Sun Ki (Dept. of Radiology, Seoul St Mary' s Hospital, Catholic Univ. of Korea, Seoul (Korea)), e-mail: whjee@catholic.ac.kr; Koh, In-Jun (Dept. of Joint Reconstruction Center, Seoul National Univ. Bundang Hospital, Seoul (Korea)); Kim, Jung-Man (Dept. of Orthopedic Surgery, Seoul St Mary' s Hospital, Catholic Univ. of Korea, Seoul (Korea))

2010-05-15

Background: Fat-suppressed (FS) proton density (PD)-weighted magnetic resonance imaging (MRI) and FS three-dimensional (3D) gradient-echo imaging such as spoiled gradient-recalled (SPGR) sequence have been established as accurate methods for detecting articular cartilage defects. Purpose: To retrospectively compare the diagnostic efficacy between FS PD-weighted and FS 3D gradient-echo MRI for differentiating between grade 3 and grade 4 cartilage defects of the knee with arthroscopy as the standard of reference. Material and Methods: Twenty-one patients who had grade 3 or 4 cartilage defects in medial femoral condyle at arthroscopy and knee MRI were included in this study: grade 3, >50% cartilage defects; grade 4, full thickness cartilage defects exposed to the bone. Sagittal FS PD-weighted MR images and FS 3D gradient-echo images with 1.5 T MR images were independently graded for the cartilage abnormalities of medial femoral condyle by two musculoskeletal radiologists. Statistical analysis was performed by Fisher's exact test. Inter-observer agreement in grading of cartilage was assessed using ? coefficients. Results: Arthroscopy revealed grade 3 defects in 17 patients and grade 4 defects in 4 patients in medial femoral condyles. For FS 3D gradient-echo images grade 3 defects were graded as grade 3 (n=15) and grade 4 (n=2), and all grade 4 defects (n=4) were correctly graded. However, for FS PD-weighted MR images all grade 3 defects were misinterpreted as grade 1 (n=1) and grade 4 (n=16), whereas all grade 4 defects (n=4) were correctly graded. FS 3D gradient-echo MRI could differentiate grade 3 from grade 4 defects (P=0.003), whereas FS PD-weighted imaging could not (P=1.0). Inter-observer agreement was substantial (?=0.70) for grading of cartilage using FS PD-weighted imaging, whereas it was moderate (?=0.46) using FS 3D gradient-echo imaging. Conclusion: FS 3D gradient-echo MRI is more helpful for differentiating between grade 3 and grade 4 cartilage

[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.

Man's Basic Needs. Resource Units, Grade 1. Providence Social Studies Curriculum Project.

Science.gov (United States)

Providence Public Schools, RI.

GRADES OR AGES: Grade 1. SUBJECT MATTER: Social studies; man's basic needs. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into 11 chapters, five of which outline the basic curriculum subunits. These five chapters are laid out in three columns, one each for topics, activities, and materials. Other chapters are in list form. The guide…

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...

Most American Academy of Orthopaedic Surgeons' online patient education material exceeds average patient reading level.

Science.gov (United States)

Eltorai, Adam E M; Sharma, Pranav; Wang, Jing; Daniels, Alan H

2015-04-01

Advancing health literacy has the potential to improve patient outcomes. The American Academy of Orthopaedic Surgeons' (AAOS) online patient education materials serve as a tool to improve health literacy for orthopaedic patients; however, it is unknown whether the materials currently meet the National Institutes of Health/American Medical Association's recommended sixth grade readability guidelines for health information or the mean US adult reading level of eighth grade. The purposes of this study were (1) to evaluate the mean grade level readability of online AAOS patient education materials; and (2) to determine what proportion of the online materials exceeded recommended (sixth grade) and mean US (eighth grade) reading level. Reading grade levels for 99.6% (260 of 261) of the online patient education entries from the AAOS were analyzed using the Flesch-Kincaid formula built into Microsoft Word software. Mean grade level readability of the AAOS patient education materials was 9.2 (SD ± 1.6). Two hundred fifty-one of the 260 articles (97%) had a readability score above the sixth grade level. The readability of the AAOS articles exceeded the sixth grade level by an average of 3.2 grade levels. Of the 260 articles, 210 (81%) had a readability score above the eighth grade level, which is the average reading level of US adults. Most of the online patient education materials from the AAOS had readability levels that are far too advanced for many patients to comprehend. Efforts to adjust the readability of online education materials to the needs of the audience may improve the health literacy of orthopaedic patients. Patient education materials can be made more comprehensible through use of simpler terms, shorter sentences, and the addition of pictures. More broadly, all health websites, not just those of the AAOS, should aspire to be comprehensible to the typical reader.

Stress corrosion cracking of L-grade stainless steels in boiling water reactor (BWR) plants

International Nuclear Information System (INIS)

Suzuki, Shunichi; Fukuda, Toshihiko; Yamashita, Hironobu

2004-01-01

L-grade stainless steels as 316NG, SUS316L and SUS304L have been used for the BWR reactor internals and re-circulation pipes as SCC resistant materials. However, SCC of the L-grade material components were reported recently in many Japanese BWR plants. The detail investigation of the components showed the fabrication process such as welding, machining and surface finishing strongly affected SCC occurrence. In this paper, research results of SCC of L-grade stainless steels, metallurgical investigation of core shrouds and re-circulation pipings, and features of SCC morphology were introduced. Besides, the structural integrity of components with SCC, countermeasures for SCC and future R and D planning were introduced. (author)

Status Report from Czechoslovakia [Processing of Low-Grade Uranium Ores

Energy Technology Data Exchange (ETDEWEB)

Civin, V; Belsky, M [Research and Development Laboratory No.3 of the Uranium Industry, Prague, Czechoslovakia (Czech Republic)

1967-06-15

The present paper deals with the fundamental problems and the main routes followed in processing low-grade uranium ores in CSSR. In this connection it may be useful to discuss the definition of low-grade ore. In our country this term is applied to uraniferous material with a very low content of uranium (of the order of 0.01%) whose treatment causes no particular difficulty. However, the same term is also used to designate those materials whose processibility lies on the verge of economic profitability. In our view, this classification, of an ore using two independent criteria (i.e. uranium content and processing economy) is useful from the standpoint of technology. The treatment of both such ore types is as a rule carried out by specific technological processes. Consequently, low-grade uranium ores can be divided into two groups: (1) Ores with a low uranium content. To this category belong in our country uraniferous materials which originate as a by-product of technological processes used in processing other materials. This is primarily gangue and tailings of various physical or physico-chemical pretreatment operations to which the ore is subjected at the mining site. Mention should be made in this connection of mine waters, which represent a useful complementary source of uranium despite their low uranium content (of the order of milligrams per litre). (2) Ores whose economical treatment is problematic. To this category belong deposits of conventional ore types with a uranium content on the limit of profitable treatment. Also, those deposits containing atypical materials possessing such properties which impair the economy of their treatment. This includes ores with a considerable amount of components which are difficult to separate and which at the same time consume the leaching agents. Finally, it covers uranium-bearing materials in refractory forms which are difficult to dissolve and also some special materials, such as lignites, uranium-bearing shales, loams

Compressive evaluation of homogeneous and graded epoxy-glass particulate composites.

Science.gov (United States)

Seaglar, J; Rousseau, C-E

2015-04-01

The propagation of stress waves in epoxy-glass particulate composites and graded materials was studied experimentally. Materials tested in this study consisted of an epoxy matrix with various concentrations of spherical glass particles having a mean diameter of 42μm. Plate impact experiments were performed using a gas gun. Embedded within the specimens were manganin stress gauges used to record propagating compressive longitudinal stress waves through the material. High strain rate experiments using a Split Hopkinson Pressure Bar (SHPB) apparatus were also performed to evaluate the dynamic strength of the specimens, while quasi-static compression tests were undertaken to characterize their quasi-static behavior. Ultrasonic wave speed measurements were carried-out in order to obtain additional material properties and characterize the gradation in functionally graded materials (FGM). It was found that low volume fractions of particles are detrimental to the performance of the material under impact loading, while concentrations in the range of about 30 to 45% by volume exhibit characteristics of higher degrees of scattering. This suggests that materials in this latter range would be more effective in the thwarting of destructive shock waves than the homogeneous matrix material. Impact testing of FGM specimens suggests that impact loading on the stiff (high volume fraction) face results in much higher levels of scattering. Therefore, such materials would be effective for use in light weight armor or as shielding materials due to their effective attenuation of mechanical impulses. Copyright © 2015 Elsevier B.V. All rights reserved.

Finite element analysis of functionally graded bone plate at femur bone fracture site

Science.gov (United States)

Satapathy, Pravat Kumar; Sahoo, Bamadev; Panda, L. N.; Das, S.

2018-03-01

This paper focuses on the analysis of fractured Femur bone with functionally graded bone plate. The Femur bone is modeled by using the data from the CT (Computerized Tomography) scan and the material properties are assigned using Mimics software. The fracture fixation plate used here is composed of Functionally Graded Material (FGM). The functionally graded bone plate is considered to be composed of different layers of homogeneous materials. Finite element method approach is adopted for analysis. The volume fraction of the material is calculated by considering its variation along the thickness direction (z) according to a power law and the effective properties of the homogeneous layers are estimated. The model developed is validated by comparing numerical results available in the literature. Static analysis has been performed for the bone plate system by considering both axial compressive load and torsional load. The investigation shows that by introducing FG bone plate instead of titanium, the stress at the fracture site increases by 63 percentage and the deformation decreases by 15 percentage, especially when torsional load is taken into consideration. The present model yields better results in comparison with the commercially available bone plates.

High maneuverability guidewire with functionally graded properties using new superelastic alloys.

Science.gov (United States)

Sutou, Y; Yamauchi, K; Suzuki, M; Furukawa, A; Omori, T; Takagi, T; Kainuma, R; Nishida, M; Ishida, K

2006-01-01

Nitinol shape memory alloys (SMAs) are attracting considerable attention as core materials for medical guidewires because of their excellent flexibility and shape retention. However, since Nitinol guidewires possess low rigidity, the pushability and torquability of the guidewires are insufficient. On the other hand, although guidewires made of stainless steel have high pushability, plastic deformation occurs easily. We have developed a new class of superelastic guidewires with functionally graded properties from the tip to the end by using new SMA core materials such as Cu-Al-Mn-based or Ni-free Ti-Mo-Sn SMAs. The tip portion of the guidewire shows excellent superelasticity (SE), while the body portion possesses high rigidity. These functionally graded characteristics can be realized by microstructural control. These guidewires with functionally graded properties show excellent pushability and torquability and are considerably easier to handle than conventional guidewires with Nitinol or stainless steel cores. Moreover, a metallic catheter using a Ni-free Ti-based SMA with high biocompatibility is introduced.

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…

Hardwood log grades and lumber grade yields for factory lumber logs

Science.gov (United States)

Leland F. Hanks; Glenn L. Gammon; Robert L. Brisbin; Everette D. Rast

1980-01-01

The USDA Forest Service Standard Grades for Hardwood Factory Lumber Logs are described, and lumber grade yields for 16 species and 2 species groups are presented by log grade and log diameter. The grades enable foresters, log buyers, and log sellers to select and grade those log suitable for conversion into standard factory grade lumber. By using the apropriate lumber...

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)

Health Literacy: Readability of ACC/AHA Online Patient Education Material.

Science.gov (United States)

Kapoor, Karan; George, Praveen; Evans, Matthew C; Miller, Weldon J; Liu, Stanley S

To determine whether the online patient education material offered by the American College of Cardiology (ACC) and the American Heart Association (AHA) is written at a higher level than the 6th-7th grade level recommended by the National Institute of Health (NIH). Online patient education material from each website was subjected to reading grade level (RGL) analysis using the Readability Studio Professional Edition. One-sample t testing was used to compare the mean RGLs obtained from 8 formulas to the NIH-recommended 6.5 grade level and 8th grade national mean. In total, 372 articles from the ACC website and 82 from the AHA were studied. Mean (±SD) RGLs for the 454 articles were 9.6 ± 2.1, 11.2 ± 2.1, 11.9 ± 1.6, 10.8 ± 1.6, 9.7 ± 2.1, 10.8 ± 0.8, 10.5 ± 2.6, and 11.7 ± 3.5 according to the Flesch-Kincaid grade level (FKGL), Simple Measure of Gobbledygook (SMOG Index), Coleman-Liau Index (CLI), Gunning-Fog Index (GFI), New Dale-Chall reading level formula (NDC), FORCAST, Raygor Readability Estimate (RRE), and Fry Graph (Fry), respectively. All analyzed articles had significantly higher RGLs than both the NIH-recommended grade level of 6.5 and the national mean grade level of 8 (p education material provided on the ACC and AHA websites is written above the NIH-recommended 6.5 grade level and 8th grade national mean reading level. Additional studies are required to demonstrate whether lowering the RGL of this material improves outcomes among patients with cardiovascular disease. © 2017 S. Karger AG, Basel.

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

OpenAIRE

Aulia Nur Arivina; Masrukan Masrukan; Ardhi Prabowo

2017-01-01

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 o...

Non-linear buckling of an FGM truncated conical shell surrounded by an elastic medium

International Nuclear Information System (INIS)

Sofiyev, A.H.; Kuruoglu, N.

2013-01-01

In this paper, the non-linear buckling of the truncated conical shell made of functionally graded materials (FGMs) surrounded by an elastic medium has been studied using the large deformation theory with von Karman–Donnell-type of kinematic non-linearity. A two-parameter foundation model (Pasternak-type) is used to describe the shell–foundation interaction. The FGM properties are assumed to vary continuously through the thickness direction. The fundamental relations, the modified Donnell type non-linear stability and compatibility equations of the FGM truncated conical shell resting on the Pasternak-type elastic foundation are derived. By using the Superposition and Galerkin methods, the non-linear stability equations for the FGM truncated conical shell is solved. Finally, influences of variations of Winkler foundation stiffness and shear subgrade modulus of the foundation, compositional profiles and shell characteristics on the dimensionless critical non-linear axial load are investigated. The present results are compared with the available data for a special case. -- Highlights: • Nonlinear buckling of FGM conical shell surrounded by elastic medium is studied. • Pasternak foundation model is used to describe the shell–foundation interaction. • Nonlinear basic equations are derived. • Problem is solved by using Superposition and Galerkin methods. • Influences of various parameters on the nonlinear critical load are investigated

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…

In-service behavior of creep strength enhanced ferritic steels Grade 91 and Grade 92 – Part 1 parent metal

International Nuclear Information System (INIS)

Parker, Jonathan

2013-01-01

In creep strength enhanced ferritic steels, such as Grade 91 and Grade 92, control of both composition and heat treatment of the parent steel is necessary to avoid producing components which have creep strength below the minimum expected by applicable ASME and other International Codes. These efforts are required to ensure that the steel develops a homogeneous fully tempered martensitic microstructure, with the appropriate distribution of precipitates and the required dislocation substructure. In-service creep related problems with Grade 91 steel have been reported associated with factors such as incorrect microstructure and heat treatment, welded connections in headers and piping, dissimilar metal welds as well as the manufacture and performance of castings. Difficulties associated with remediation of in-service damage include challenges over detection and removal of damaged material as well as the selection and qualification of appropriate methodologies for repair. Since repeated heat treatment leads to continued tempering, and a potential degradation of properties, specific procedures for performing and then lifing repair welds are a key aspect of Asset Management. This paper presents a summary of in-service experience with Grade 91 steel and outlines approaches for repair welding. Highlights: ► The steel alloy known as Grade 91 is widely used to fabricate critical pressure part components. ► Designers favor Grade 91 because it provides superior elevated temperature strength at substantially lower cost than the austenitic stainless steels. ► Service experience has confirmed that early failures can occur. ► Life management solutions involved attention to detail at Purchase, during design and all stages of fabrication.

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...

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

references. The technical assessment is supplemented by an evaluation of practical application and overall energy balance. Applying the developed method to 4 references and 18 unproven low-grade potential fuels, indicated that one of these unproven candidates was most likely unsuited for Pyroneer...... 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...

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)

Using learning materials for design-based interventions

DEFF Research Database (Denmark)

Gissel, Stig Toke

2015-01-01

This article considers a methodological issue concerning the use of learning materials for interventions in design-based research. When the researcher uses existing or creates new didacticised learning materials for research purposes and tests their applicability in authentic contexts, many...... variables are in play. When using or designing a learning material a lot of choices have to be made and effects are difficult to isolate. The advantage of using learning materials for interventions is that results could have high ecological validity. In the article this methodological issue is exemplified...... through a research project using and developing digital learning materials for developing literacy in the early grades. One of many important choices to be made in elaborating this learning material concerns which texts should be used for supporting students’ literacy development in the lower grades...

Effect of concrete strength gradation to the compressive strength of graded concrete, a numerical approach

Science.gov (United States)

Pratama, M. Mirza Abdillah; Aylie, Han; Gan, Buntara Sthenly; Umniati, B. Sri; Risdanareni, Puput; Fauziyah, Shifa

2017-09-01

Concrete casting, compacting method, and characteristic of the concrete material determine the performance of concrete as building element due to the material uniformity issue. Previous studies show that gradation in strength exists on building member by nature and negatively influence the load carrying capacity of the member. A pilot research had modeled the concrete gradation in strength with controllable variable and observed that the weakest material determines the strength of graded concrete through uniaxial compressive loading test. This research intends to confirm the recent finding by a numerical approach with extensive variables of strength disparity. The finite element analysis was conducted using the Strand7 nonlinear program. The results displayed that the increase of strength disparity in graded concrete models leads to the slight reduction of models strength. A substantial difference in displacement response is encountered on the models for the small disparity of concrete strength. However, the higher strength of concrete mix in the graded concrete models contributes to the rise of material stiffness that provides a beneficial purpose for serviceability of building members.

Three-dimensional free vibration of functionally graded truncated conical shells subjected to thermal environment

Energy Technology Data Exchange (ETDEWEB)

Malekzadeh, P., E-mail: p_malekz@yahoo.com [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Fiouz, A.R.; Sobhrouyan, M. [Department of Civil Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of)

2012-01-15

A three-dimensional (3D) free vibration analysis of the functionally graded (FG) truncated conical shells subjected to thermal environment is presented. The material properties are assumed to be temperature-dependent and graded in the radius direction, which can vary according to a simple power law distribution. The initial thermal stresses are obtained accurately by solving the thermoelastic equilibrium equations and by considering the two-dimensional axisymmetric temperature distribution in the shell. The differential quadrature method (DQM) as an efficient and accurate numerical tool is adopted to solve the thermal and thermo-mechanical governing equations. For this purpose, a mapping technique is employed to transform the cross section of the shell into the computational domain of DQM. The convergence behavior of the method is numerically demonstrated and comparison studies with the available solutions in the literature are performed. The effects of temperature dependence of material properties, geometrical parameters, material graded index, thermal and mechanical boundary conditions on the frequency parameters of the FG truncated conical shells are carried out. - Highlights: Black-Right-Pointing-Pointer 3D free vibration analysis of the functionally graded truncated conical shells is presented. Black-Right-Pointing-Pointer Two-dimensional axisymmetric temperature distribution in the shell is assumed. Black-Right-Pointing-Pointer The material properties are assumed to be temperature-dependent. Black-Right-Pointing-Pointer Initial thermal stresses due to thermal environment are evaluated accurately and included. Black-Right-Pointing-Pointer Representing the effects of different parameters on the non-dimensional frequencies.

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

AGC 2 Irradiated Material Properties Analysis

Energy Technology Data Exchange (ETDEWEB)

Rohrbaugh, David Thomas [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-05-01

The Advanced Reactor Technologies Graphite Research and Development Program is conducting an extensive graphite irradiation experiment to provide data for licensing of a high temperature reactor (HTR) design. In past applications, graphite has been used effectively as a structural and moderator material in both research and commercial high temperature gas cooled reactor designs. , Nuclear graphite H 451, used previously in the United States for nuclear reactor graphite components, is no longer available. New nuclear graphite grades have been developed and are considered suitable candidates for new HTR reactor designs. To support the design and licensing of HTR core components within a commercial reactor, a complete properties database must be developed for these current grades of graphite. Quantitative data on in service material performance are required for the physical, mechanical, and thermal properties of each graphite grade, with a specific emphasis on data accounting for the life limiting effects of irradiation creep on key physical properties of the HTR candidate graphite grades. Further details on the research and development activities and associated rationale required to qualify nuclear grade graphite for use within the HTR are documented in the graphite technology research and development plan.

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.

Readability assessment of online urology patient education materials.

Science.gov (United States)

Colaco, Marc; Svider, Peter F; Agarwal, Nitin; Eloy, Jean Anderson; Jackson, Imani M

2013-03-01

The National Institutes of Health, American Medical Association, and United States Department of Health and Human Services recommend that patient education materials be written at a fourth to sixth grade reading level to facilitate comprehension. We examined and compared the readability and difficulty of online patient education materials from the American Urological Association and academic urology departments in the Northeastern United States. We assessed the online patient education materials for difficulty level with 10 commonly used readability assessment tools, including the Flesch Reading Ease Score, Flesch-Kincaid Grade Level, Simple Measure of Gobbledygook, Gunning Frequency of Gobbledygook, New Dale-Chall Test, Coleman-Liau index, New Fog Count, Raygor Readability Estimate, FORCAST test and Fry score. Most patient education materials on the websites of these programs were written at or above the eleventh grade reading level. Urological online patient education materials are written above the recommended reading level. They may need to be simplified to facilitate better patient understanding of urological topics. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

A new MRI grading system for chondromalacia patellae.

Science.gov (United States)

Özgen, Ali; Taşdelen, Neslihan; Fırat, Zeynep

2017-04-01

Background Chondromalacia patellae is a very common disorder. Although magnetic resonance imaging (MRI) is widely used to investigate patellar cartilage lesions, there is no descriptive MRI-based grading system for chondromalacia patellae. Purpose To propose a new MRI grading system for chondromalacia patellae with corresponding high resolution images which might be useful in precisely reporting and comparing knee examinations in routine daily practice and used in predicting natural course and clinical outcome of the patellar cartilage lesions. Material and Methods High resolution fat-saturated proton density (FS PD) images in the axial plane with corresponding T2 mapping images were reviewed. A detailed MRI grading system covering the deficiencies of the existing gradings has been set and presented on these images. Two experienced observers blinded to clinical data examined 44 knee MR images and evaluated patellar cartilage changes according to the proposed grading system. Inter- and intra-rater validity testing using kappa statistics were calculated. Results A descriptive and detailed grading system with corresponding FS PD and T2 mapping images has been presented. Inter-rater agreement was 0.80 (95% confidence interval [CI], 0.71-0.89). Intra-rater agreements were 0.83 (95% CI, 0.74-0.91) for observer A and 0.79 (95% CI, 0.70-0.88) for observer B (k-values). Conclusion We present a new MRI grading system for chondromalacia patellae with corresponding images and good inter- and intra-rater agreement which might be useful in reporting and comparing knee MRI examinations in daily practice and may also have the potential for using more precisely predicting prognosis and clinical outcome of the patients.

Characterization of food-grade titanium dioxide: the presence of nanosized particles.

Science.gov (United States)

Yang, Yu; Doudrick, Kyle; Bi, Xiangyu; Hristovski, Kiril; Herckes, Pierre; Westerhoff, Paul; Kaegi, Ralf

2014-06-03

Titanium dioxide (TiO2) is widely used in food products, which will eventually enter wastewater treatment plants and terrestrial or aquatic environments, yet little is known about the fraction of this TiO2 that is nanoscale, or the physical and chemical properties of TiO2 that influence its human and environmental fate or toxicity. Instead of analyzing TiO2 properties in complex food or environmental samples, we procured samples of food-grade TiO2 obtained from global food suppliers and then, using spectroscopic and other analytical techniques, quantified several parameters (elemental composition, crystal structure, size, and surface composition) that are reported to influence environmental fate and toxicity. Another sample of nano-TiO2 that is generally sold for catalytic applications (P25) and widely used in toxicity studies, was analyzed for comparison. Food-grade and P25 TiO2 are engineered products, frequently synthesized from purified titanium precursors, and not milled from bulk scale minerals. Nanosized materials were present in all of the food-grade TiO2 samples, and transmission electron microscopy showed that samples 1-5 contained 35, 23, 21, 17, and 19% of nanosized primary particles (average hydrodynamic diameter of >100 nm. Food-grade samples contained phosphorus (P), with concentrations ranging from 0.5 to 1.8 mg of P/g of TiO2. The phosphorus content of P25 was below inductively coupled plasma mass spectrometry detection limits. Presumably because of a P-based coating detected by X-ray photoelectron spectroscopy, the ζ potential of the food-grade TiO2 suspension in deionized water ranged from -10 to -45 mV around pH 7, and the iso-electric point for food-grade TiO2 (grade materials, and although the presence of amorphous TiO2 could not be ruled out, it is unlikely on the basis of Raman analysis. The food-grade TiO2 was solar photoactive. Cationic dyes adsorbed more readily to food-grade TiO2 than P25, indicating very different potentials for

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

Using Cut-off grade isograms to delineate ore body and calculate parameter

International Nuclear Information System (INIS)

Yu Yongfeng; Zhu Xiaobing; Deng Yonghui

2014-01-01

Taking a uranium mine for an example, using cut-off grade isograms to achieve automatic delineation of ore body and calculation of parameters are explored. With center line of catalog sampling as baseline, the number of sampling and length of sampling constructing rectangular grid and grade as elevation value, isograms of cut-off grade were drawn, thus achieving the delineation of the ore body. Then, the other parameters of the ore body can be calculated. Compared with the traditional hand drawing method, the work efficiency was greatly improved, and the material inquiry was more convenient. (authors)

DECS tries out instructional materials on AIDS prevention education.

Science.gov (United States)

1994-01-01

A national try-out of the newly developed print and non-print instructional materials on AIDS Education is being conducted by the Department of Education, Culture and Sports (DECS) this school year 1993-to 1994. To determine the effectiveness of these materials, various public and private schools in Region IV (Southern Tagalog), VII (Central Visayas) XI (Southern Mindanao) and National Capital Region (Metro, Manila) were chosen as try-out institutions. The AIDS education materials will be tried out in different subjects in some grade and year levels such as civics and culture (grade one); science and health (grades three and six); home economics and livelihood education (grade five); physical education, health and music (second year) and Pilipino Language (third year). The materials for the elementary level consist of posters, cut-out pictures, voice tapes, jingles, talking books and slides, while the secondary school level utilizes modules. For the tertiary level, a Resource Book on AIDS Prevention Education is used by the Teacher Training Institutions and the Non-Formal Education employs the Facilitator's Guide for Levels I-III. These materials will be tried out in both urban and rural schools, with control school and experimental school at each level. full text

Non-invasive tryptophan fluorescence measurements as a novel method of grading cataract

DEFF Research Database (Denmark)

Erichsen, Jesper Høiberg; Mensah, Aurore; Kessel, Line

2017-01-01

. 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, R2 = 0.515. Our experiment showed that preoperative optical grading of cataracts by Scheimpflug imaging may......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...

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.

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.

Biological response of human mesenchymal stromal cells to titanium grade 4 implants coated with PCL/ZrO2 hybrid materials synthesized by sol–gel route: in vitro evaluation

International Nuclear Information System (INIS)

Catauro, M.; Bollino, F.; Papale, F.; Mozetic, P.; Rainer, A.; Trombetta, M.

2014-01-01

The surface modification of implantable materials in order to improve their biological proprieties, including tissue tolerance and osseointegration ability, by means of functional coating deposition is a promising strategy to provide a firm fixation of the implants. In this study, organic/inorganic hybrid materials consisting of an inorganic zirconia-based matrix, in which a biocompatible polymer, poly(ε-caprolactone) (PCL), has been incorporated at different percentages, have been synthesized via sol–gel route. Developed materials have been used to coat titanium grade 4 substrates by means of dip coating technique. Scanning electron microscopy (SEM) analysis of the obtained coatings has shown that films crack-free can be obtained for high levels of PCL. Chemical composition and interactions between organic and inorganic moieties have been studied by Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy. The bone-bonding capability of the nanocomposite films has been evaluated in vitro by examining the appearance of an apatite layer on their surface when soaked in a simulated body fluid by means of SEM equipped with EDS microanalysis. In vitro biocompatibility assessment was performed in combination with human mesenchymal stromal cells (hMSCs). Materials were found to be non-toxic and supporting cell proliferation. Additionally, the coating material was not hampering the differentiation of hMSCs in an osteogenic medium. - Highlights: • ZrO 2 /PCL hybrid coatings on Ti grade 4 were obtained by sol–gel dip coating process. • The PCL acts as a plasticizer and allows us to prepare crack-free coatings. • Independent of PCL amount, the films improve the titanium substrates' bioactivity. • The coatings are non-toxic and supportive of cell proliferation at all compositions. • The coatings don't hamper hMSC differentiation in an osteogenic medium

Finite Element Analysis of the Deformation of Functionally Graded Plates under Thermomechanical Loads

Directory of Open Access Journals (Sweden)

A. E. Alshorbagy

2013-01-01

Full Text Available The first-order shear deformation plate model, accounting for the exact neutral plane position, is exploited to investigate the uncoupled thermomechanical behavior of functionally graded (FG plates. Functionally graded materials are mainly constructed to operate in high temperature environments. Also, FG plates are used in many applications (such as mechanical, electrical, and magnetic, where an amount of heat may be generated into the FG plate whenever other forms of energy (electrical, magnetic, etc. are converted into thermal energy. Several simulations are performed to study the behavior of FG plates, subjected to thermomechanical loadings, and focus the attention on the effect of the heat source intensity. Most of the previous studies have considered the midplane neutral one, while the actual position of neutral plane for functionally graded plates is shifted and should be firstly determined. A comparative study is performed to illustrate the effect of considering the neutral plane position. The volume fraction of the two constituent materials of the FG plate is varied smoothly and continuously, as a continuous power function of the material position, along the thickness of the plate.

Secondary Schools Curriculum Guide, Mathematics, Grades 10-12. Revised.

Science.gov (United States)

Cranston School Dept., RI.

Behavioral objectives for grades 10 through 12 are specified for plane geometry, algebra, general mathematics, computer mathematics, slide rule mathematics, basic college mathematics, trigonometry, analytic geometry, calculus and probability. Most sections present material in terms of portions of a school year. At least one major objective is…

Grade Inflation in Medical Student Radiation Oncology Clerkships: Missed Opportunities for Feedback?

International Nuclear Information System (INIS)

Grover, Surbhi; Swisher-McClure, Samuel; Sosnowicz, Stasha; Li, Jiaqi; Mitra, Nandita; Berman, Abigail T.; Baffic, Cordelia; Vapiwala, Neha; Freedman, Gary M.

2015-01-01

Purpose: To test the hypothesis that medical student radiation oncology elective rotation grades are inflated and cannot be used to distinguish residency applicants. Methods and Materials: The records of 196 applicants to a single radiation oncology residency program in 2011 and 2012 were retrospectively reviewed. The grades for each rotation in radiation oncology were collected and converted to a standardized 4-point grading scale (honors, high pass, pass, fail). Pass/fail grades were scored as not applicable. The primary study endpoint was to compare the distribution of applicants' grades in radiation oncology with their grades in medicine, surgery, pediatrics, and obstetrics/gynecology core clerkships. Results: The mean United States Medical Licensing Examination Step 1 score of the applicants was 237 (range, 188-269), 43% had additional Masters or PhD degrees, and 74% had at least 1 publication. Twenty-nine applicants were graded for radiation oncology rotations on a pass/fail basis and were excluded from the final analysis. Of the remaining applicants (n=167), 80% received the highest possible grade for their radiation oncology rotations. Grades in radiation oncology were significantly higher than each of the other 4 clerkships studied (P<.001). Of all applicants, 195 of 196 matched into a radiation oncology residency. Higher grades in radiation oncology were associated with significantly higher grades in the pediatrics core clerkship (P=.002). However, other medical school performance metrics were not significantly associated with higher grades in radiation oncology. Conclusions: Although our study group consists of a selected group of radiation oncology applicants, their grades in radiation oncology clerkships were highly skewed toward the highest grades when compared with grades in other core clerkships. Student grading in radiation oncology clerkships should be re-evaluated to incorporate more objective and detailed performance metrics to allow for

Low-grade hardwood lumber production, markets, and issues

Science.gov (United States)

Dan Cumbo; Robert Smith; Philip A. Araman

2003-01-01

Due to recent downturn in the economy and changes in traditional hardwood markets. U.S. hardwood manufacturers are facing significant difficulties. In particular, markets for low-grade lumber have been diminishing, while increased levels of the material are being produced at hardwood sawmills in the United States. A nationwide survey of hardwood lumber manufacturers...

A New Class of Functionally Graded Cearamic-Metal Composites for Next Generation Very High Temperature Reactors

International Nuclear Information System (INIS)

Jain, Mohit; Skandan, Ganesh; Khose, Gordon E.; Maro, Judith

2008-01-01

Generation IV Very High Temperature power generating nuclear reactors will operate at temperatures greater than 900 C. At these temperatures, the components operating in these reactors need to be fabricated from materials with excellent thermo-mechanical properties. Conventional pure or composite materials have fallen short in delivering the desired performance. New materials, or conventional materials with new microstructures, and associated processing technologies are needed to meet these materials challenges. Using the concept of functionally graded materials, we have fabricated a composite material which has taken advantages of the mechanical and thermal properties of ceramic and metals. Functionally-graded composite samples with various microstructures were fabricated. It was demonstrated that the composition and spatial variation in the composition of the composite can be controlled. Some of the samples were tested for irradiation resistance to neutrons. The samples did not degrade during initial neutron irradiation testing.

"A New Class od Functionally Graded Cearamic-Metal Composites for Next Generation Very High Temperature Reactors"

Energy Technology Data Exchange (ETDEWEB)

Dr. Mohit Jain; Dr. Ganesh Skandan; Dr. Gordon E. Khose; Mrs. Judith Maro, Nuclear Reactor Laboratory, MIT

2008-05-01

Generation IV Very High Temperature power generating nuclear reactors will operate at temperatures greater than 900 oC. At these temperatures, the components operating in these reactors need to be fabricated from materials with excellent thermo-mechanical properties. Conventional pure or composite materials have fallen short in delivering the desired performance. New materials, or conventional materials with new microstructures, and associated processing technologies are needed to meet these materials challenges. Using the concept of functionally graded materials, we have fabricated a composite material which has taken advantages of the mechanical and thermal properties of ceramic and metals. Functionally-graded composite samples with various microstructures were fabricated. It was demonstrated that the composition and spatial variation in the composition of the composite can be controlled. Some of the samples were tested for irradiation resistance to neutrons. The samples did not degrade during initial neutron irradiation testing.

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...

Graded gauge theory

International Nuclear Information System (INIS)

Kerner, R.

1983-01-01

The mathematical background for a graded extension of gauge theories is investigated. After discussing the general properties of graded Lie algebras and what may serve as a model for a graded Lie group, the graded fiber bundle is constructed. Its basis manifold is supposed to be the so-called superspace, i.e. the product of the Minkowskian space-time with the Grassmann algebra spanned by the anticommuting Lorentz spinors; the vertical subspaces tangent to the fibers are isomorphic with the graded extension of the SU(N) Lie algebra. The connection and curvature are defined then on this bundle; the two different gradings are either independent of each other, or may be unified in one common grading, which is equivalent to the choice of the spin-statistics dependence. The Yang-Mills lagrangian is investigated in the simplified case. The conformal symmetry breaking is discussed, as well as some other physical consequences of the model. (orig.)

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.

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)

Teachers' Grading Decision Making

Science.gov (United States)

Isnawati, Ida; Saukah, Ali

2017-01-01

This study investigated teachers' grading decision making, focusing on their beliefs underlying their grading decision making, their grading practices and assessment types, and factors they considered in grading decision making. Two teachers from two junior high schools applying different curriculum policies in grade reporting in Indonesian…

Readability of Written Materials for CKD Patients: A Systematic Review.

Science.gov (United States)

Morony, Suzanne; Flynn, Michaela; McCaffery, Kirsten J; Jansen, Jesse; Webster, Angela C

2015-06-01

The "average" patient has a literacy level of US grade 8 (age 13-14 years), but this may be lower for people with chronic kidney disease (CKD). Current guidelines suggest that patient education materials should be pitched at a literacy level of around 5th grade (age 10-11 years). This study aims to evaluate the readability of written materials targeted at patients with CKD. Systematic review. Patient information materials aimed at adults with CKD and written in English. Patient education materials designed to be printed and read, sourced from practices in Australia and online at all known websites run by relevant international CKD organizations during March 2014. Quantitative analysis of readability using Lexile Analyzer and Flesch-Kincaid tools. We analyzed 80 materials. Both Lexile Analyzer and Flesch-Kincaid analyses suggested that most materials required a minimum of grade 9 (age 14-15 years) schooling to read them. Only 5% of materials were pitched at the recommended level (grade 5). Readability formulas have inherent limitations and do not account for visual information. We did not consider other media through which patients with CKD may access information. Although the study covered materials from the United States, United Kingdom, and Australia, all non-Internet materials were sourced locally, and it is possible that some international paper-based materials were missed. Generalizability may be limited due to exclusion of non-English materials. These findings suggest that patient information materials aimed at patients with CKD are pitched above the average patient's literacy level. This issue is compounded by cognitive decline in patients with CKD, who may have lower literacy than the average patient. It suggests that information providers need to consider their audience more carefully when preparing patient information materials, including user testing with a low-literacy patient population. Copyright © 2015 National Kidney Foundation, Inc. Published by

GREEN OAK AS A SUSTAINABLE BUILDING MATERIAL

Science.gov (United States)

Technical documentation necessary for a project demonstrating the viability of green oak as a contemporary structural material. These will include material grading guidelines, mechanical testing, architectural construction documents and details, specifications, engineering cal...

Development of functionally graded materials by ultrasonic consolidation

CSIR Research Space (South Africa)

Kumar, S

2010-08-01

Full Text Available parameters for welding various combinations of materials have been found for making a sample of aminimumo f62 foils of width 2” and length 3”. Optical microscopy and mirohardness test have been performed thereupon for the characterization....

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...

Geometrically non linear analysis of functionally graded material ...

African Journals Online (AJOL)

The nonlinear algebraic equations are solved using Newton Raphson iterative method. The numerical results are obtained for various boundary conditions, material variation parameter, aspect ratio, side to thickness ratio and compared with the available solutions. The effect of shear deformation and nonlinearity response ...

Prognostic significance of multiple kallikreins in high-grade astrocytoma

International Nuclear Information System (INIS)

Drucker, Kristen L.; Gianinni, Caterina; Decker, Paul A.; Diamandis, Eleftherios P.; Scarisbrick, Isobel A.

2015-01-01

Kallikreins have clinical value as prognostic markers in a subset of malignancies examined to date, including kallikrein 3 (prostate specific antigen) in prostate cancer. We previously demonstrated that kallikrein 6 is expressed at higher levels in grade IV compared to grade III astrocytoma and is associated with reduced survival of GBM patients. In this study we determined KLK1, KLK6, KLK7, KLK8, KLK9 and KLK10 protein expression in two independent tissue microarrays containing 60 grade IV and 8 grade III astrocytoma samples. Scores for staining intensity, percent of tumor stained and immunoreactivity scores (IR, product of intensity and percent) were determined and analyzed for correlation with patient survival. Grade IV glioma was associated with higher levels of kallikrein-immunostaining compared to grade III specimens. Univariable Cox proportional hazards regression analysis demonstrated that elevated KLK6- or KLK7-IR was associated with poor patient prognosis. In addition, an increased percent of tumor immunoreactive for KLK6 or KLK9 was associated with decreased survival in grade IV patients. Kaplan-Meier survival analysis indicated that patients with KLK6-IR < 10, KLK6 percent tumor core stained < 3, or KLK7-IR < 9 had a significantly improved survival. Multivariable analysis indicated that the significance of these parameters was maintained even after adjusting for gender and performance score. These data suggest that elevations in glioblastoma KLK6, KLK7 and KLK9 protein have utility as prognostic markers of patient survival. The online version of this article (doi:10.1186/s12885-015-1566-5) contains supplementary material, which is available to authorized users

Biological response of human mesenchymal stromal cells to titanium grade 4 implants coated with PCL/ZrO{sub 2} hybrid materials synthesized by sol–gel route: in vitro evaluation

Energy Technology Data Exchange (ETDEWEB)

Catauro, M., E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Bollino, F.; Papale, F. [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Mozetic, P.; Rainer, A.; Trombetta, M. [Tissue Engineering Lab, Center for Integrated Research, “Università Campus Bio-Medico di Roma”, via Alvaro del Portillo, 00128 Rome (Italy)

2014-12-01

The surface modification of implantable materials in order to improve their biological proprieties, including tissue tolerance and osseointegration ability, by means of functional coating deposition is a promising strategy to provide a firm fixation of the implants. In this study, organic/inorganic hybrid materials consisting of an inorganic zirconia-based matrix, in which a biocompatible polymer, poly(ε-caprolactone) (PCL), has been incorporated at different percentages, have been synthesized via sol–gel route. Developed materials have been used to coat titanium grade 4 substrates by means of dip coating technique. Scanning electron microscopy (SEM) analysis of the obtained coatings has shown that films crack-free can be obtained for high levels of PCL. Chemical composition and interactions between organic and inorganic moieties have been studied by Attenuated Total Reflectance Fourier Transform InfraRed spectroscopy. The bone-bonding capability of the nanocomposite films has been evaluated in vitro by examining the appearance of an apatite layer on their surface when soaked in a simulated body fluid by means of SEM equipped with EDS microanalysis. In vitro biocompatibility assessment was performed in combination with human mesenchymal stromal cells (hMSCs). Materials were found to be non-toxic and supporting cell proliferation. Additionally, the coating material was not hampering the differentiation of hMSCs in an osteogenic medium. - Highlights: • ZrO{sub 2}/PCL hybrid coatings on Ti grade 4 were obtained by sol–gel dip coating process. • The PCL acts as a plasticizer and allows us to prepare crack-free coatings. • Independent of PCL amount, the films improve the titanium substrates' bioactivity. • The coatings are non-toxic and supportive of cell proliferation at all compositions. • The coatings don't hamper hMSC differentiation in an osteogenic medium.

The Readability of AAOS Patient Education Materials: Evaluating the Progress Since 2008.

Science.gov (United States)

Roberts, Heather; Zhang, Dafang; Dyer, George S M

2016-09-07

The Internet has become a major resource for patients; however, patient education materials are frequently written at relatively high levels of reading ability. The purpose of this study was to evaluate the readability of patient education materials on the American Academy of Orthopaedic Surgeons (AAOS) web site. Readability scores were calculated for all patient education articles on the AAOS web site using 5 algorithms: Flesch Reading Ease, Flesch-Kincaid Grade Level, SMOG (Simple Measure of Gobbledygook) Grade, Coleman-Liau Index, and Gunning-Fog Index. The mean readability scores were compared across the anatomic categories to which they pertained. Using a liberal measure of readability, the Flesch-Kincaid Grade Level, 3.9% of articles were written at or below the recommended sixth-grade reading level, and 84% of the articles were written above the eighth-grade reading level. Articles in the present study had a lower mean Flesch-Kincaid Grade Level than those available in 2008 (p readability levels of AAOS articles are higher than generally recommended. Although the mean Flesch-Kincaid Grade Level was lower in the present study than it was in 2008, a need remains to improve the readability of AAOS patient education articles. Ensuring that online patient education materials are written at an appropriate reading grade level would be expected to improve physician-patient communication. Copyright © 2016 by The Journal of Bone and Joint Surgery, Incorporated.

Growth of optical grade germanium crystals

International Nuclear Information System (INIS)

Waris, M.; Akhtar, M.J.; Mehmood, N.; Ashraf, M.; Siddique, M.

2011-01-01

A novel design of Czochralski( CZ ) growth station in a low frequency induction furnace is described and growth of optical grade Ge crystal as a test material is performed achieving a flat solid-liquid interface shape. Grown Ge crystals are annealed in air at 450 -500 deg. C for 4 hrs and then characterized by determination of crystallographic orientation by Laue (back-reflection of X-rays) method, dislocation density studies by etch-pits formation, measuring electrical resistivity by 4-probe technique, conductivity type determination by hot probe method, measurement of hardness on Moh's scale and optical transmission measurement in IR region. The results obtained are compared to those reported in the literature. The use of this growth station for other materials is suggested. (author)

Kinder Lernen Deutsch. Materials Project Part I. Revised.

Science.gov (United States)

American Association of Teachers of German.

The Kinder Lernen Deutsch (LKD) materials evaluation project identifies materials appropriate for the elementary school German classrooms in grades K-8. This guide consists of an annotated bibliography, with ratings, of these materials. The guiding principles by which the materials were assessed were: use of the communicative approach; integration…

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.

Readability evaluation of Internet-based patient education materials related to the anesthesiology field.

Science.gov (United States)

De Oliveira, Gildasio S; Jung, Michael; Mccaffery, Kirsten J; McCarthy, Robert J; Wolf, Michael S

2015-08-01

The main objective of the current investigation was to assess the readability of Internet-based patient education materials related to the field of anesthesiology. We hypothesized that the majority of patient education materials would not be written according to current recommended readability grade level. Online patient education materials describing procedures, risks, and management of anesthesia-related topics were identified using the search engine Google (available at www.google.com) using the terms anesthesia, anesthesiology, anesthesia risks, and anesthesia care. Cross-sectional evaluation. None. Assessments of content readability were performed using validated instruments (Flesch-Kincaid Grade Formulae, the Gunning Frequency of Gobbledygook, the New Dale-Chall Test, the Fry graph, and the Flesch Reading Ease score). Ninety-six Web sites containing Internet patient education materials (IPEMs) were evaluated. The median (interquartile range) readability grade level for all evaluated IPEMs was 13.5 (12.0-14.6). All the evaluated documents were classified at a greater readability level than the current recommended readability grade, P Internet-based patient education materials related to the field of anesthesiology are currently written far above the recommended readability grade level. High complexity of written education materials likely limits access of information to millions of American patients. Redesign of online content of Web sites that provide patient education material regarding anesthesia could be an important step in improving access to information for patients with poor health literacy. Copyright © 2015 Elsevier Inc. All rights reserved.

[Qualitative characteristics and classification study on commodity specification and grade standard of Panax notoginseng].

Science.gov (United States)

Liu, Da-Hui; Xu, Na; Guo, Lan-Ping; Jin, Yan; Cui, Xiu-Ming; Yang, Ye; Zhu, Xin-Yan; Zhan, Zhi-Lai; Huang, Lu-Qi

2016-03-01

Through the markets investigations and literature surveying, this paper investigates and analyzes the qualitative characteristics and commodity condition of Panax notoginseng. And the samples collected from market and origin were analyzed in order to revise the commodity specification and grade standard of P. notoginseng combined with production practice. In this paper, the authors divide the P. notoginseng into 4 commodity specification which are root (including Cunqi and Dongqi ), Rhizome and rootlet according to different parts and harvest time. And the root were divided into 8 grade which are 20, 30, 40, 60, 80, 120, countless and substandard. The density and internal components between the different commodity specification and grade of P. notoginseng were also compared. As well as the effect of different producing area, cultivation years and harvesting time on the commodity specification and grade of P. notoginseng were researched. On this basis, we revise and improve the commodity specification and grade standard of P. notoginseng. Moreover, we suggest the quality control indexes of P. notoginseng should be developed according to the different medicinal part and commodity specification in CHP. In order to guide the standardized production of traditional Chinese medicine and ensure the quality of medicinal materials, the cultivation years and density of each medicinal materials should also be indicated in CHP. Copyright© by the Chinese Pharmaceutical Association.

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.

Comparative analysis of online patient education material pertaining to hepatitis and its complications.

Science.gov (United States)

Gulati, Rishabh; Nawaz, Mohammad; Pyrsopoulos, Nikolaos T

2016-05-01

Approximately 50% of patients leave the doctor's office with a poor understanding of their diagnosis. Online patient education websites are becoming a major source of information for many of the patients. Here, we determine the reading grade level of online patient education materials on hepatitis B, hepatitis C, cirrhosis, and hepatocellular cancer and compare it with the National Institutes of Health-recommended reading grade level of sixth to seventh grade or under. A Google search was performed to retrieve patient reading materials. Text was modified to remove medical terms that were defined within the article. Documents were then divided into categories of introduction, risk factors, symptoms, diagnosis, treatment, and prevention. Each document was then analyzed using six validated readability tests to determine the grade level and complexity on the basis of the number of words, syllables, or number of uncommon words. Modified documents had a mean readability score of 10.23, although the recommended score is less than 7.0. Cirrhosis had the highest reading grade level, with a median of 11.3, whereas hepatitis B and hepatocellular carcinoma had the easiest readability, with a median of 9.5. Furthermore, treatment subsection was the most difficult, with a median score of 10.8. Patient reading materials reviewed in this study were written well above the recommended reading grade level. These findings suggest review of patient education materials in an effort to close the gap between the average reading level and the reading materials.

Readability of Patient Education Materials From the Web Sites of Orthopedic Implant Manufacturers.

Science.gov (United States)

Yi, Meghan M; Yi, Paul H; Hussein, Khalil I; Cross, Michael B; Della Valle, Craig J

2017-12-01

Prior studies indicate that orthopedic patient education materials are written at a level that is too high for the average patient. The purpose of this study was to assess the readability of online patient education materials provided by orthopedic implant manufacturers. All patient education articles available in 2013 from the web sites of the 5 largest orthopedic implant manufacturers were identified. Each article was evaluated with the Flesch-Kincaid (FK) readability test. The number of articles with readability ≤ the eighth-grade level (average reading ability of US adults) and the sixth-grade level (recommended level for patient education materials) was determined. Mean readability levels of each company's articles were compared using analysis of variance (significance set at P articles were reviewed from the 5 largest implant manufacturers. The mean overall FK grade level was 10.9 (range, 3.8-16.1). Only 58 articles (10%) were written ≤ the eighth-grade level, and only 13 (2.2%) were ≤ the sixth-grade level. The mean FK grade level was significantly different among groups (Smith & Nephew = 12.0, Stryker = 11.6, Biomet = 11.3, DePuy = 10.6, Zimmer = 10.1; P education materials from implant manufacturers are written at a level too high to be comprehended by the average patient. Future efforts should be made to improve the readability of orthopedic patient education materials. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Grade control and the determination of ore reserves at a low-grade uranium mine

International Nuclear Information System (INIS)

Reid, J.A.F.; Robertson, B.

1982-01-01

In 1966 an intensive exploration programme was conducted by Rio Tinto South Africa Ltd, involving airborne and ground radiometric surveys, percussion and diamond drilling, and pilot-plant tests. This investigation established the presence of a large deposit of low-grade uranium that could be mined on a large scale by open-pitting. Soon after production started in June 1974, it was realized that the original presentation of the ore reserves did not give a true reflection of the orebody. A comparison between the estimates and the ore mined from reserve blocks over the period 1975 to 1977 showed that the reserve grades were over-optimistic. In 1977 Rio Tinto Zinc Consultants were commissioned to re-evaluate the ore reserves from exploration diamond-drill data with the help of The Centre de Geostatistique at Fontainebleau, France. A new global reserve using disjunctive kriging techniques was developed, and is now the long-term reserve used for planning purposes at the Roessing Mine. For short-term planning, ore-reserve data are replaced by information from an intermediate drilling programme and blast-hole assays if these are available. A computerized short-term planning system has been established that reconciles the ore mined against the reserve blocks, as well as a system by which composited blast-hole assays are analysed for grade-control purposes. Owing to the complexity of the orebody, additional monitoring is achieved by the scanning of each truckload of ore with a group of scintillation crystal heads that evaluate the material mined

PDGF-metronidazole-encapsulated nanofibrous functional layers on collagen membrane promote alveolar ridge regeneration

Directory of Open Access Journals (Sweden)

Ho MH

2017-08-01

Full Text Available Ming-Hua Ho,1 Hao-Chieh Chang,2,3 Yu-Chia Chang,3 Jeiannete Claudia,1 Tzu-Chiao Lin,2 Po-Chun Chang2,3 1Department of Chemical Engineering, College of Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 2Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan; 3Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan Abstract: This study aimed to develop a functionally graded membrane (FGM to prevent infection and promote tissue regeneration. Poly(L-lactide-co-D,L-lactide encapsulating platelet-derived growth factor (PDLLA-PDGF or metronidazole (PDLLA-MTZ was electrospun to form a nanofibrous layer on the inner or outer surface of a clinically available collagen membrane, respectively. The membrane was characterized for the morphology, molecule release profile, in vitro and in vivo biocompatibility, and preclinical efficiency for alveolar ridge regeneration. The PDLLA-MTZ and PDLLA-PDGF nanofibers were 800–900 nm in diameter, and the thicknesses of the functional layers were 20–30 µm, with sustained molecule release over 28 days. All of the membranes tested were compatible with cell survival in vitro and showed good tissue integration with minimal fibrous capsule formation or inflammation. Cell proliferation was especially prominent on the PDLLA-PDGF layer in vivo. On the alveolar ridge, all FGMs reduced wound dehiscence compared with the control collagen membrane, and the FGM with PDLLA-PDGF promoted osteogenesis significantly. In conclusion, the FGMs with PDLLA-PDGF and PDLLA-MTZ showed high biocompatibility and facilitated wound healing compared with conventional membrane, and the FGM with PDLLA-PDGF enhanced alveolar ridge regeneration in vivo. The design represents a beneficial modification, which may be easily adapted for future clinical use. Keywords: tissue engineering, platelet-derived growth factor, metronidazole, alveolar process

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure

Directory of Open Access Journals (Sweden)

Liying Jiang

2011-12-01

Full Text Available In this work, the problem of a curved functionally graded piezoelectric (FGP actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure.

Science.gov (United States)

Yan, Zhi; Zaman, Mostafa; Jiang, Liying

2011-12-12

In this work, the problem of a curved functionally graded piezoelectric (FGP) actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g 31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

Sonographic features of invasive ductal breast carcinomas predictive of malignancy grade

Directory of Open Access Journals (Sweden)

Kanika Gupta

2018-01-01

Full Text Available Context: Assessment of individual sonographic features provides vital clues about the biological behavior of breast masses and can assist in determining histological grade of malignancy and thereby prognosis. Aims: Assessment of individual sonographic features of biopsy proven invasive ductal breast carcinomas as predictors of malignancy grade. Settings and Design: A retrospective analysis of sonographic findings of 103 biopsy proven invasive ductal breast carcinomas. Materials and Methods: Tumor characteristics on gray-scale ultrasound and color flow were assessed using American College of Radiology (ACR Breast Imaging Reporting and Data System (BI-RADS Atlas Fifth Edition. The sonographic findings of masses were individually correlated with their histopathologic grades. Statistical Analysis Used: Chi square test, ordinal regression, and Goodman and Kruskal tau test. Results: Breast mass showing reversal/lack of diastolic flow has a high probability of belonging to histological high grade tumor ( β 1.566, P 0.0001. The masses with abrupt interface boundary are more likely grade 3 ( β 1.524, P 0.001 in comparison to masses with echogenic halos. The suspicious calcifications present in and outside the mass is a finding associated with histologically high grade tumors. The invasive ductal carcinomas (IDCs with complex solid and cystic echotexture are more likely to be of high histological grade ( β 1.146, P 0.04 as compared to masses with hypoechoic echotexture. Conclusions: Certain ultrasound features are associated with tumor grade on histopathology. If the radiologist is cognizant of these sonographic features, ultrasound can be a potent modality for predicting histopathological grade of IDCs of the breast, especially in settings where advanced tests such as receptor and molecular analyses are limited.

A semi-analytical three-dimensional free vibration analysis of functionally graded curved panels

Energy Technology Data Exchange (ETDEWEB)

Zahedinejad, P. [Department of Mechanical Engineering, Islamic Azad University, Branch of Shiraz, Shiraz (Iran, Islamic Republic of); Malekzadeh, P., E-mail: malekzadeh@pgu.ac.i [Department of Mechanical Engineering, Persian Gulf University, Persian Gulf University Boulevard, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of); Farid, M. [Department of Mechanical Engineering, Islamic Azad University, Branch of Shiraz, Shiraz (Iran, Islamic Republic of); Karami, G. [Department of Mechanical Engineering and Applied Mechanics, North Dakota State University, Fargo, ND 58105-5285 (United States)

2010-08-15

Based on the three-dimensional elasticity theory, free vibration analysis of functionally graded (FG) curved thick panels under various boundary conditions is studied. Panel with two opposite edges simply supported and arbitrary boundary conditions at the other edges are considered. Two different models of material properties variations based on the power law distribution in terms of the volume fractions of the constituents and the exponential distribution of the material properties through the thickness are considered. Differential quadrature method in conjunction with the trigonometric functions is used to discretize the governing equations. With a continuous material properties variation assumption through the thickness of the curved panel, differential quadrature method is efficiently used to discretize the governing equations and to implement the related boundary conditions at the top and bottom surfaces of the curved panel and in strong form. The convergence of the method is demonstrated and to validate the results, comparisons are made with the solutions for isotropic and FG curved panels. By examining the results of thick FG curved panels for various geometrical and material parameters and subjected to different boundary conditions, the influence of these parameters and in particular, those due to functionally graded material parameters are studied.

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 ...

Transient Stress Intensity Factors of Functionally Graded Hollow Cylinders with Internal Circumferential Cracks

Directory of Open Access Journals (Sweden)

Iman Eshraghi

Full Text Available Abstract In this paper, transient thermomechanical stress intensity factors for functionally graded cylinders with complete internal circumferential cracks are obtained using the weight function method. The finite difference method is used to calculate the time dependent temperature distribution and thermal stresses along the cylinder thickness. Furthermore, finite element analysis is performed to determine the weight function coefficients and to investigate the accuracy of the predicted stress intensity factors from the weight functions. Variation of the stress intensity factors with time and effects of the material gradation on the results are investigated, as well. It is shown that the proposed technique can be used to accurately predict transient thermomechanical stress intensity factors for functionally graded cylinders with arbitrary material gradation.

Plasmonic color-graded nanosystems with achromatic sub-wavelength architectures for light filtering and advanced SERS detection

KAUST Repository

Proietti Zaccaria, Remo

2016-03-09

Plasmonic colour-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale colour filters; their typical size is small enough to allow integration with miniaturized electronic circuits paving the way to realize novel nanophotonic devices. Currently, most plasmonic colour-graded systems are intrinsically discrete, as their chromatic response exploits the tailored plasmon resonance of micro-architectures characterized by different size and/or geometry for each target colour. Here we report the realization of multifunctional plasmon-graded devices where continuously-graded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength, but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, like photovoltaic efficiency boosters or colour routers await, and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.

Plasmonic color-graded nanosystems with achromatic sub-wavelength architectures for light filtering and advanced SERS detection

KAUST Repository

Proietti Zaccaria, Remo; Bisio, Francesco; Das, Gobind; Maidecchi, Giulia; Caminale, Michael; Vu, Chinh Duc; De Angelis, Francesco; Di Fabrizio, Enzo M.; Toma, Andrea; Canepa, Maurizio

2016-01-01

Plasmonic colour-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale colour filters; their typical size is small enough to allow integration with miniaturized electronic circuits paving the way to realize novel nanophotonic devices. Currently, most plasmonic colour-graded systems are intrinsically discrete, as their chromatic response exploits the tailored plasmon resonance of micro-architectures characterized by different size and/or geometry for each target colour. Here we report the realization of multifunctional plasmon-graded devices where continuously-graded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength, but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, like photovoltaic efficiency boosters or colour routers await, and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.

Readability of patient education materials on the American Orthopaedic Society for Sports Medicine website.

Science.gov (United States)

Eltorai, Adam E M; Han, Alex; Truntzer, Jeremy; Daniels, Alan H

2014-11-01

The recommended readability of patient education materials by the American Medical Association (AMA) and National Institutes of Health (NIH) should be no greater than a sixth-grade reading level. However, online resources may be too complex for some patients to understand, and poor health literacy predicts inferior health-related quality of life outcomes. This study evaluated whether the American Orthopaedic Society for Sports Medicine (AOSSM) website's patient education materials meet recommended readability guidelines for medical information. We hypothesized that the readability of these online materials would have a Flesch-Kincaid formula grade above the sixth grade. All 65 patient education entries of the AOSSM website were analyzed for grade level readability using the Flesch-Kincaid formula, a widely used and validated tool to evaluate the text reading level. The average (standard deviation) readability of all 65 articles was grade level 10.03 (1.44); 64 articles had a readability score above the sixth-grade level, which is the maximum level recommended by the AMA and NIH. Mean readability of the articles exceeded this level by 4.03 grade levels (95% CI, 3.7-4.4; P reading level of US adults. Mean readability of the articles exceeded this level by 2.03 grade levels (95% CI, 1.7-2.4; P online AOSSM patient education materials exceeds the readability level recommended by the AMA and NIH, and is above the average reading level of the majority of US adults. This online information may be of limited utility to most patients due to a lack of comprehension. Our study provides a clear example of the need to improve the readability of specific education material in order to maximize the efficacy of multimedia sources.

Size-dependent electro-magneto-elastic bending analyses of the shear-deformable axisymmetric functionally graded circular nanoplates

Science.gov (United States)

Arefi, Mohammad; Zenkour, Ashraf M.

2017-10-01

This paper develops nonlocal elasticity equations and magneto-electro-elastic relations to size-dependent electro-magneto-elastic bending analyses of the functionally graded axisymmetric circular nanoplates based on the first-order shear deformation theory. All material properties are graded along the thickness direction based on exponential varying. It is assumed that a circular nanoplate is made from piezo-magnetic materials. The energy method and Ritz approach is employed for the derivation of governing equations of electro-magneto-elastic bending and the solution of the problem, respectively. The nanoplate is subjected to applied electric and magnetic potentials at top and transverse loads while it is rested on Pasternak's foundation. Some important numerical results are presented in various figures to show the influence of applied electric and magnetic potentials, small scale parameter and inhomogeneous index of an exponentially graded nanoplate.

Sugar cane leaf: a potential raw material for cheap grades of paper and board

Energy Technology Data Exchange (ETDEWEB)

Tiwary, K. N.; Kulkarni, A. Y.

1980-03-15

About 6 to 7 million tons of sugar cane leaves are available per year as agricultural residue and can be utilized for manufacture of cheap grades of paper and board. An unbleached yield of 56% could be obtained using 10% NaOH at a temperature of 170/sup 0/C with a bath ratio of 1 to 4 and cooking time of 10 min. Sulfate pulping with equivalent conditions gave a bleached pulp with comparatively higher brightness values, other properties remaining almost same. Bleaching of 10% soda pulp with 10 and 12% chlorine have given 42 and 40% yields at 71 to 72 and 77 to 78% Elrepho brightness, respectively. In case of 9% sulfate pulp the yields are 36 to 37% at 77 to 79% brightness when bleached with the same sequence as above with 10 to 10.5% chlorine. The pulps are strong for preparation of cheap grades of bleached as well as unbleached varieties of paper. Double fold and tear are however medium to low and hence need long fibered pulp blending to improve these characteristics.

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.

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…

Transient response of rotating laminated functionally graded cylindrical shells in thermal environment

International Nuclear Information System (INIS)

Malekzadeh, P.; Heydarpour, Y.; Haghighi, M.R. Golbahar; Vaghefi, M.

2012-01-01

Based on the elasticity theory, the transient analysis of dynamically pressurized rotating multi-layered functionally graded (FG) cylindrical shells in thermal environment is presented. The variations of the field variables across the shell thickness are accurately modeled by dividing the shell into a set of co-axial mathematical layers in the radial direction. The initial thermo-mechanical stresses are obtained by solving the thermoelastic equilibrium equations. The differential quadrature method and Newmark's time integration scheme are employed to discretize the obtained governing equations of each mathematical layer. After performing the convergence and comparison studies, parametric studies for two common types of FG sandwich shells, namely, the shell with homogeneous inner/outer layers and FG core and the shell with FG inner/outer layers and homogeneous core are carried out. The influences of the temperature dependence of material properties, material graded index, the convective heat transfer coefficient, the angular velocity, the boundary condition and the geometrical parameters (length and thickness to outer radius ratios) on the dynamic response of the FG shells are investigated. Highlights: ► As a first endeavor, transient analysis of rotating laminated functionally graded cylinders. ► Employing an elasticity based discrete layer-differential quadrature method. ► Evaluating and including the initial thermo-mechanical stresses accurately. ► Considering the temperature-dependence of the material properties. ► Presenting some new results, which can be used as benchmark solution for future works.

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.

Initial Comparison of Baseline Physical and Mechanical Properties for the VHTR Candidate Graphite Grades

Energy Technology Data Exchange (ETDEWEB)

Carroll, Mark C. [Idaho National Lab. (INL), Idaho Falls, ID (United States). VHTR Program

2014-09-01

High-purity graphite is the core structural material of choice in the Very High Temperature Reactor (VHTR) design, a graphite-moderated, helium-cooled configuration capable of producing thermal energy for power generation as well as process heat for industrial applications that require temperatures higher than the outlet temperatures of present nuclear reactors. The Baseline Graphite Characterization Program is establishing accurate as-manufactured mechanical and physical property distributions in nuclear-grade graphites by providing comprehensive data that captures the level of variation in measured values. In addition to providing a thorough comparison between these values in different graphite grades, the program is also carefully tracking individual specimen source, position, and orientation information in order to provide comparisons both in specific properties and in the associated variability between different lots, different billets, and different positions from within a single billet. This report is a preliminary comparison between each of the grades of graphite that are considered “candidate” grades from four major international graphite producers. These particular grades (NBG-18, NBG-17, PCEA, IG-110, and 2114) are the major focus of the evaluations presently underway on irradiated graphite properties through the series of Advanced Graphite Creep (AGC) experiments. NBG-18, a medium-grain pitch coke graphite from SGL from which billets are formed via vibration molding, was the favored structural material in the pebble-bed configuration. NBG-17 graphite from SGL is essentially NBG-18 with the grain size reduced by a factor of two. PCEA, petroleum coke graphite from GrafTech with a similar grain size to NBG-17, is formed via an extrusion process and was initially considered the favored grade for the prismatic layout. IG-110 and 2114, from Toyo Tanso and Mersen (formerly Carbone Lorraine), respectively, are fine-grain grades produced via an isomolding

Neutron irradiation behavior of ITER candidate beryllium grades

Energy Technology Data Exchange (ETDEWEB)

Kupriyanov, I.B.; Gorokhov, V.A.; Nikolaev, G.N. [A.A.Bochvar All-Russia Scientific Research Inst. of Inorganic Materials (VNIINM), Moscow (Russian Federation); Melder, R.R.; Ostrovsky, Z.E.

1998-01-01

Beryllium is one of the main candidate materials both for the neutron multiplier in a solid breeding blanket and for the plasma facing components. That is why its behaviour under the typical for fusion reactor loading, in particular, under the neutron irradiation is of a great importance. This paper presents mechanical properties, swelling and microstructure of six beryllium grades (DshG-200, TR-30, TshG-56, TRR, TE-30, TIP-30) fabricated by VNIINM, Russia and also one - (S-65) fabricated by Brush Wellman, USA. The average grain size of the beryllium grades varied from 8 to 25 {mu}m, beryllium oxide content was 0.8-3.2 wt. %, initial tensile strength was 250-680 MPa. All the samples were irradiated in active zone of SM-3 reactor up to the fast neutron fluence (5.5-6.2) {center_dot} 10{sup 21} cm{sup -2} (2.7-3.0 dpa, helium content up to 1150 appm), E > 0.1 MeV at two temperature ranges: T{sub 1} = 130-180degC and T{sub 2} = 650-700degC. After irradiation at 130-180degC no changes in samples dimensions were revealed. After irradiation at 650-700degC swelling of the materials was found to be in the range 0.1-2.1 %. Beryllium grades TR-30 and TRR, having the smallest grain size and highest beryllium oxide content, demonstrated minimal swelling, which was no more than 0.1 % at 650-700degC and fluence 5.5 {center_dot} 10{sup 21} cm{sup -2}. Tensile and compression test results and microstructure parameters measured before and after irradiation are also presented. (author)

High temperature material characterization and advanced materials development

International Nuclear Information System (INIS)

Ryu, Woo Seog; Kim, D. H.; Kim, S. H. and others

2005-03-01

The study is to characterize the structural materials under the high temperature, one of the most significant environmental factors in nuclear systems. And advanced materials are developed for high temperature and/or low activation in neutron irradiation. Tensile, fatigue and creep properties have been carried out at high temperature to evaluate the mechanical degradation. Irradiation tests were performed using the HANARO. The optimum chemical composition and heat treatment condition were determined for nuclear grade 316NG stainless steel. Nitrogen, aluminum, and tungsten were added for increasing the creep rupture strength of FMS steel. The new heat treatment method was developed to form more stable precipitates. By applying the novel whiskering process, high density SiC/SiC composites with relative density above 90% could be obtained even in a shorter processing time than the conventional CVI process. Material integrated databases are established using data sheets. The databases of 6 kinds of material properties are accessible through the home page of KAERI material division

From Russian weapons grade plutonium to MOX fuel

International Nuclear Information System (INIS)

Braehler, G.; Kudriavtsev, E.G.; Seyve, C.

1997-01-01

The April 1996, G7 Moscow Summit on nuclear matters provided a political framework for one of the most current significant challenges: ensuring a consistent answer to the weapons grade fissile material disposition issue resulting from the disarmament effort engaged by both the USA and Russia. International technical assessments have showed that the transformation of Weapons grade Plutonium in MOX fuel is a very efficient, safe, non proliferant and economically effective solution. In this regard, COGEMA and SIEMENS, have set up a consistent technical program properly addressing incineration of weapons grade plutonium in MOX fuels. The leading point of this program would be the construction of a Weapons grade Plutonium dedicated MOX fabrication plant in Russia. Such a plant would be based on the COGEMA-SIEMENS industrial capabilities and experience. This facility would be operated by MINATOM which is the partner for COGEMA-SIEMENS. MINATOM is in charge of coordination of the activity of the Russian research and construction institutes. The project take in account international standards for non-proliferation, safety and waste management. France and Germany officials reasserted this position during their last bilateral summits held in Fribourg in February and in Dijon in June 1996. MINATOM and the whole Russian nuclear community have already expressed their interest to cooperate with COGEMA-SIEMENS in the MOX field. This follows governmental-level agreements signed in 1992 by French, German and Russian officials. For years, Russia has been dealing with research and development on MOX fabrication and utilization. So, the COGEMA-SIEMENS MOX proposal gives a realistic answer to the management of weapons grade plutonium with regard to the technical, industrial, cost and schedule factors. (author)

Standard specification for nuclear-grade beryllium oxide powder

International Nuclear Information System (INIS)

Anon.

1984-01-01

This specification defines the physical and chemical requirements of nuclear-grade beryllium oxide (BeO) powder to be used in fabricating nuclear components. This specification does not include requirements for health and safety. It recognizes the material as a Class B poison and suggests that producers and users become thoroughly familiar with and comply to applicable federal, state and local regulations and handling guidelines. Special tests and procedures are given

Implementation of GPS Machine Controlled Grading - Phase III (2008) and Technical Training

Science.gov (United States)

2009-02-01

Beginning in 2006, WisDOT and the Construction Material and Support Center (CMSC) at UW-Madison worked together to develop the specifications and the QA/QC procedures for GPS machine guidance on highway grading projects. These specifications and proc...

Vibration analysis of a functionally graded piezoelectric cylindrical actuator

International Nuclear Information System (INIS)

Zhang, T T; Shi, Z F; Spencer, B F Jr

2008-01-01

This paper focuses on the response of a functionally graded piezoelectric cylindrical actuator placed in a harmonic electric field based on elastic membrane theory and shell theory. The actuator is polarized in the radial direction with its piezoelectric coefficient d 31 varying linearly along the axial direction. In the present investigation, non-dimensional expressions are introduced, and analytical solutions for this class of actuator are obtained. The results provided in the present study are compared with other investigations, with good agreement being found. The major differences between a functionally graded actuator and an actuator with homogeneous material properties are identified, and the advantages of the former are demonstrated. In the last section of this paper, limitations of membrane theory and shell theory models are discussed

Readability of patient education materials in ophthalmology: a single-institution study and systematic review.

Science.gov (United States)

Williams, Andrew M; Muir, Kelly W; Rosdahl, Jullia A

2016-08-03

Patient education materials should be written at a level that is understandable for patients with low health literacy. The aims of this study are (1) to review the literature on readability of ophthalmic patient education materials and (2) to evaluate and revise our institution's patient education materials about glaucoma using evidence-based guidelines on writing for patients with low health literacy. A systematic search was conducted on the PubMed/MEDLINE database for studies that have evaluated readability level of ophthalmic patient education materials, and the reported readability scores were assessed. Additionally, we collected evidence-based guidelines for writing easy-to-read patient education materials, and these recommendations were applied to revise 12 patient education handouts on various glaucoma topics at our institution. Readability measures, including Flesch-Kincaid Grade Level (FKGL), and word count were calculated for the original and revised documents. The original and revised versions of the handouts were then scored in random order by two glaucoma specialists using the Suitability Assessment of Materials (SAM) instrument, a grading scale used to evaluate suitability of health information materials for patients. Paired t test was used to analyze changes in readability measures, word count, and SAM score between original and revised handouts. Finally, five glaucoma patients were interviewed to discuss the revised materials, and patient feedback was analyzed qualitatively. Our literature search included 13 studies that evaluated a total of 950 educational materials. Among the mean FKGL readability scores reported in these studies, the median was 11 (representing an eleventh-grade reading level). At our institution, handouts' readability averaged a tenth-grade reading level (FKGL = 10.0 ± 1.6), but revising the handouts improved their readability to a sixth-grade reading level (FKGL = 6.4 ± 1.2) (p readability and suitability of

Bespoke Materials For Bespoke Textile Architecture

DEFF Research Database (Denmark)

Tamke, Martin; Baranovskaya, Yuliya; Holden Deleuran, Anders

2016-01-01

Membrane architecture uses currently off the shelf materials and produces the shapes and details through cutting and laborsome joining of textile patterns. This paper discusses investigations into an alternative material practice - knit - which engages bespoke membrane materials. A practice which...... allows for customised and graded material properties, the direct fabrication of shaped patterns and the integration of detailing directly into the membrane material. Based on two demonstrators built as hybrids of bespoke CNC knit and bending active GFRP rods this paper discusses the affordances...

Assessment of long-term creep strength of grade 91 steel

Energy Technology Data Exchange (ETDEWEB)

Kimura, Kazuhiro; Sawada, Kota; Kushima, Hideaki [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan)

2010-07-01

In 2004 and 2005 long-term creep rupture strength of ASME Grade 91 type steels of plate, pipe, forging and tube materials was evaluated in Japan by means of region splitting analysis method in consideration of 50% of 0.2% offset yield stress. According to the evaluated 100,000h creep rupture strength of 94MPa for plate, pipe and forging steels and 92MPa for tube steel at 600 C, allowable tensile stress of the steels regulated in the Interpretation for the Technical Standard for Thermal Power Plant was slightly reduced. New creep rupture data of the steels obtained in the long-term indicate further reduction of long-term creep rupture strength. Not only creep rupture strength, but also creep deformation property of the ASME Grade 91 steel was investigated and need of reevaluation of long-term creep strength of Grade 91 steel was indicated. A refinement of region splitting analysis method for creep rupture like prediction was discussed. (orig.)

The Factor Structure of Coordination Abilities Development in 5th-7th Grade Boys

Directory of Open Access Journals (Sweden)

В. В. Приходько

2017-12-01

Full Text Available The objective is to determine the structure of coordination abilities development in 5th-7th grade boys. Materials and methods. The participants in the study were boys of the 5th grade (n=21, 6th grade (n=20, and 7th grade (n=19. The paper used analysis and generalization of the scientific and methodological literature data, general scientific methods of theoretical level, namely: analogy, analysis, synthesis, abstracting, induction, as well as general scientific methods of empirical level: observation, testing, experiment. To evaluate of the motor preparedness, the results of motor tests, height and body weight were recorded. The materials of the study were processed in the statistical analysis program IBM SPSS 20. Factor analysis was carried out using a model of the principal components with the rotation method: Variamax with Kaiser normalization. Results. Analysis of the similarities shows that the most informative in the structure of the 5th grade boys’ motor preparedness are Test 9 “Static Equilibrium Evaluation by E. Ya. Bondarevsky’s Method” (,999, Test 2 “Standing Long Jump (cm” (,998, Test 10 “Dynamic Equilibrium Evaluation by Bess Method” (,916; for the 6th grade boys such are Test 9 “Static Equilibrium Evaluation by E. Ya. Bondarevsky’s Method” (1.0, Test 2 “Standing Long Jump (cm” (,999, Test 5 “Sit-Up for 30 sec.” (,968, Test 10 “Dynamic Equilibrium Evaluation by Bess Method” (,918; for the 7th grade boys such are Test 2 “Standing Long Jump (cm” (,994, Test 9 “Static Equilibrium Evaluation by E. Ya. Bondarevsky’s Method” (,987, Test 10 “Dynamic Equilibrium Evaluation by Bess Method” (,945. Conclusions. The most informative in the structure of 5th-7th grade boys’ coordination abilities is vestibular tolerance. For pedagogical control of 5th-7th grade boys’ motor preparedness the following can be recommended: Test 2 “Standing Long Jump (cm”, Test 9 “Static Equilibrium

Correlation between aging grade of T91 steel and spectral characteristics of the laser-induced plasma

Energy Technology Data Exchange (ETDEWEB)

Li, Jun [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Dai, Yuan [Electric Power Research Institute of Guangdong Power Grid Company, Guangzhou 510080 (China); Dong, Meirong [Power Electric College in South China University of Technology, Guangzhou 510640 (China); Zhong, Wanli [Electric Power Research Institute of Guangdong Power Grid Company, Guangzhou 510080 (China); Yao, Shunchun [Power Electric College in South China University of Technology, Guangzhou 510640 (China)

2015-08-15

Highlights: • Laser-induced breakdown spectroscopy (LIBS) was first employed to estimate the aging grade of T91 steel. • The differences from the ionic-to-atomic ratio of the same elements indicated that the grade is the reason to cause the difference of the plasma characteristics. • Good unique value correlations between the peak intensity ratio of CrI/FeI, MoI/FeI and the aging grade were found. • The research indicates that LIBS technique is a potential way to estimate the aging grade of T91 steel. - Abstract: T91 steel with favorable mechanical performance has become the representative heat-resistant steel used as heat exchange surfaces in supercritical and ultra-supercritical boilers. The organizational structure and mechanical properties change during the service period, called material aging, which affects the service life and the equipment safety. To develop a fast and easy aging predictive technique of heat exchange metal surfaces, laser-induced breakdown spectroscopy (LIBS) was applied to investigate the plasma characteristics of T91 steel specimens with different aging grades. The metallographic structure, mechanical properties and spectral characteristics of the specimens were analyzed. Then, the correlations between the spectral characteristics and the aging grade were established. The analysis results show that the martensite substructure disappears, and the dimension of the carbide particles among the crystal lattices increases with aging. At the same time, the hardness of the samples gradually decreases. The peak intensities of both the matrix and the alloying element increases then decreases with aging, owing to the change of the metallography structure and mechanical properties. Furthermore, good unique value correlations between the intensity ratio of CrI/FeI, MoI/FeI and the aging grade are found. This demonstrates that LIBS is a possible new way to estimate the aging grade of metal materials.

Correlation between aging grade of T91 steel and spectral characteristics of the laser-induced plasma

International Nuclear Information System (INIS)

Li, Jun; Lu, Jidong; Dai, Yuan; Dong, Meirong; Zhong, Wanli; Yao, Shunchun

2015-01-01

Highlights: • Laser-induced breakdown spectroscopy (LIBS) was first employed to estimate the aging grade of T91 steel. • The differences from the ionic-to-atomic ratio of the same elements indicated that the grade is the reason to cause the difference of the plasma characteristics. • Good unique value correlations between the peak intensity ratio of CrI/FeI, MoI/FeI and the aging grade were found. • The research indicates that LIBS technique is a potential way to estimate the aging grade of T91 steel. - Abstract: T91 steel with favorable mechanical performance has become the representative heat-resistant steel used as heat exchange surfaces in supercritical and ultra-supercritical boilers. The organizational structure and mechanical properties change during the service period, called material aging, which affects the service life and the equipment safety. To develop a fast and easy aging predictive technique of heat exchange metal surfaces, laser-induced breakdown spectroscopy (LIBS) was applied to investigate the plasma characteristics of T91 steel specimens with different aging grades. The metallographic structure, mechanical properties and spectral characteristics of the specimens were analyzed. Then, the correlations between the spectral characteristics and the aging grade were established. The analysis results show that the martensite substructure disappears, and the dimension of the carbide particles among the crystal lattices increases with aging. At the same time, the hardness of the samples gradually decreases. The peak intensities of both the matrix and the alloying element increases then decreases with aging, owing to the change of the metallography structure and mechanical properties. Furthermore, good unique value correlations between the intensity ratio of CrI/FeI, MoI/FeI and the aging grade are found. This demonstrates that LIBS is a possible new way to estimate the aging grade of metal materials

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…

High-grade and low-grade gliomas: differentiation by using perfusion MR imaging

International Nuclear Information System (INIS)

Hakyemez, B.; Erdogan, C.; Ercan, I.; Ergin, N.; Uysal, S.; Atahan, S.

2005-01-01

AIM: Relative cerebral blood volume (rCBV) is a commonly used perfusion magnetic resonance imaging (MRI) technique for the evaluation of tumour grade. Relative cerebral blood flow (rCBF) has been less studied. The goal of our study was to determine the usefulness of these parameters in evaluating the histopathological grade of the cerebral gliomas. METHODS: This study involved 33 patients (22 high-grade and 11 low-grade glioma cases). MRI was performed for all tumours by using a first-passage gadopentetate dimeglumine T2*-weighted gradient-echo single-shot echo-planar sequence followed by conventional MRI. The rCBV and rCBF were calculated by deconvolution of an arterial input function. The rCBV and rCBF ratios of the lesions were obtained by dividing the values obtained from the normal white matter of the contralateral hemisphere. For statistical analysis Mann-Whitney testing was carried out. A p value of less than 0.05 indicated a statistically significant difference. Receiver operating characteristic curve (ROC) analysis was performed to assess the relationship between the rCBV and rCBF ratios and grade of gliomas. Their cut-off value permitting discrimination was calculated. The correlation between rCBV and CBF ratios and glioma grade was assessed using Pearson correlation analysis. RESULTS: In high-grade gliomas, rCBV and rCBF ratios were measured as 6.50±4.29 and 3.32±1.87 (mean±SD), respectively. In low-grade gliomas, rCBV and rCBF ratios were 1.69±0.51 and 1.16±0.38, respectively. The rCBV and rCBF ratios for high-grade gliomas were statistically different from those of low-grade gliomas (p 0.05). The cut-off value was taken as 1.98 in the rCBV ratio and 1.25 in the rCBF ratio. There was a strong correlation between the rCBV and CBF ratios (Pearson correlation = 0.830, p<0.05). CONCLUSION: Perfusion MRI is useful in the preoperative assessment of the histopathologicalal grade of gliomas; the rCBF ratio in addition to the rCBV ratio can be incorporated

Modified Graded Repair of Cerebrospinal Fluid Leaks in Endoscopic Endonasal Transsphenoidal Surgery

Science.gov (United States)

Park, Jae-Hyun; Choi, Jai Ho; Kim, Young-Il; Kim, Sung Won

2015-01-01

Objective Complete sellar floor reconstruction is critical to avoid postoperative cerebrospinal fluid (CSF) leakage during transsphenoidal surgery. Recently, the pedicled nasoseptal flap has undergone many modifications and eventually proved to be valuable and efficient. However, using these nasoseptal flaps in all patients who undergo transsphenoidal surgery, including those who had none or only minor CSF leakage, appears to be overly invasive and time-consuming. Methods Patients undergoing endoscopic endonasal transsphenoidal tumor surgery within a 5 year-period were reviewed. Since 2009, we classified the intraoperative CSF leakage into grades from 0 to 3. Sellar floor reconstruction was tailored to each leak grade. We did not use any tissue grafts such as abdominal fat and did not include any procedures of CSF diversions such as lumbar drainage. Results Among 200 cases in 188 patients (147 pituitary adenoma and 41 other pathologies), intraoperative CSF leakage was observed in 27.4% of 197 cases : 14.7% Grade 1, 4.6% Grade 2a, 3.0% Grade 2b, and 5.1% Grade 3. Postoperative CSF leakage was observed in none of the cases. Septal bone buttress was used for Grade 1 to 3 leakages instead of any other foreign materials. Pedicled nasoseptal flap was used for Grades 2b and 3 leakages. Unused septal bones and nasoseptal flaps were repositioned. Conclusion Modified classification of intraoperative CSF leaks and tailored repair technique in a multilayered fashion using an en-bloc harvested septal bone and vascularized nasoseptal flaps is an effective and reliable method for the prevention of postoperative CSF leaks. PMID:26279811

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…

GRADE Equity Guidelines 3

DEFF Research Database (Denmark)

Welch, Vivian A; Akl, Elie A; Pottie, Kevin

2017-01-01

OBJECTIVE: The aim of this paper is to describe a conceptual framework for how to consider health equity in the GRADE (Grading Recommendations Assessment and Development Evidence) guideline development process. STUDY DESIGN AND SETTING: Consensus-based guidance developed by the GRADE working grou...

In the assessment of supratentorial glioma grade: The combined role of multivoxel proton MR spectroscopy and diffusion tensor imaging

International Nuclear Information System (INIS)

Zou, Q.-G.; Xu, H.-B.; Liu, F.; Guo, W.; Kong, X.-C.; Wu, Y.

2011-01-01

Aim: To detect a difference in the parameters derived from proton magnetic resonance spectroscopy ( 1 H-MRS) and diffusion tensor imaging (DTI) between low-grade and high-grade gliomas, and to evaluate whether the combination of these two techniques can improve the diagnostic accuracy of conventional magnetic resonance imaging (MRI) in supratentorial glioma grading. Materials and methods: Thirty patients with histologically proved supratentorial brain gliomas (12 low grade, 18 high grade) were prospectively evaluated with contrast material-enhanced MRI, DTI, and multivoxel 1 H-MRS (135 ms echo time). The tumour grades determined using the three methods were then compared with those obtained at histopathology. Receiver operating characteristic (ROC) analyses were performed to determine the optimum thresholds for glioma grading. Independent sample t-test, Spearman's rank correlation, and the Fisher's exact test were also carried out for statistical analysis. p -6 mm 2 /s for the calculated ADC value, corresponding to the maximum Youden index from the ROC curve of the above-selected parameters, the resultant sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Kappa values were all higher and the fraction of misclassified tumour was lower when compared with conventional MRI. However, only NAA/Cho and ADC calculation contributed to the significant difference (p < 0.01) in the assessment of glioma grade compared to conventional MRI alone, and the grading results of statistical tests comparing those two parameters were highly consistent (kappa value = 0.798). Conclusion: Thresholds for NAA/Cho and calculated ADC values, corresponding to maximum Youden index from ROC curve analyses, helped to improve the accuracy of supratentorial glioma grading when compared with conventional MRI alone. In addition, a combination of NAA/Cho and ADC calculation were more useful together than each alone in a clinical setting to evaluate

A simplified analytical approach to calculation of the electromagnetic behavior of left-handed metamaterials with a graded refractive index profile

Directory of Open Access Journals (Sweden)

Dalarsson N.

2007-01-01

Full Text Available We investigated the spectral properties of a new class of nanostructured artificial composite materials with tailored electromagnetic response, i.e. negative refractive index materials, also known as "left-handed" metamaterials. We analyzed structures incorporating both ordinary positive index media and negative refractive index metamaterials where the interface may be graded to an arbitrary degree. Utilizing a modified version of the Rosen-Morse function, we derived analytical expressions for the field intensity and spectral reflection and transmission through a graded interface between positive and negative index materials. We compared our results to numerical solutions obtained using the transfer matrix technique. .

Get on Board the Underground Railroad: A Sample Unit for Fifth-Grade History Students.

Science.gov (United States)

Ferguson, Phyllis M.; Young, Terrell A.

1996-01-01

Reviews the materials and procedures used in a fifth-grade history unit on the Underground Railroad. The unit integrated a variety of teaching methods and materials making extensive use of historical literature, K-W-L (what we Know, what we Want to find out, what we Learned) charts, and activities aimed at different learning styles. (MJP)

Probabilistic Modelling of Timber Material Properties

DEFF Research Database (Denmark)

Nielsen, Michael Havbro Faber; Köhler, Jochen; Sørensen, John Dalsgaard

2001-01-01

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 grading of timber in the production line. It is shown how statistical models may be established...... on the basis of the same type of information which is normally collected as a part of the quality control procedures and furthermore, how the efficiency of different control procedures may be compared. The tail behavior of the probability distributions of timber material characteristics play an important role...... such that they may readily be applied in structural reliability analysis and the format appears to be appropriate for codification purposes of quality control and selection for grading procedures...

Titrimetric determination of uranium in low-grade ores by the ferrous ion-phosphoric acid reduction method

International Nuclear Information System (INIS)

Hitchen, A.; Zechanowitsch, G.

1980-01-01

The modification and extension of the U.S.A.E.C. ferrous ion-phosphoric acid reduction method for the determination of uranium in high-grade or relatively pure material to a method for the determination of uranium with a high accuracy and precision, in ores containing 0.004 to 7% U is described. It is simple, rapid and requires no prior separations from elements that, in other methods, frequently interfere. For sample materials having very high concentrations of interfering elements, a prior concentration step using extraction with tri-n-octylphosphine oxide is described, but it is shown that, for most low-grade ores, this step is unnecessary. (author)

Automated grading of wood-slabs. The development of a prototype system

DEFF Research Database (Denmark)

Ersbøll, Bjarne Kjær; Conradsen, Knut

1992-01-01

This paper proposes a method for automatically grading small beechwood slabs. The method involves two classification steps: the first step detects defects based on local visual texture; the second step utilizes the relative distribution of defects to perform a final grading assessment. At a major...... as much as possible. A vast range of types of defects has to be considered when the grading is done. This and the fact that wood is a 'natural' material means it is not easily described using ordinary vision systems. The proposed method assumes a 3-D feature space which depends on local texture......-based measures of 'lightness', 'speckle' and 'dark deviation'. These measures are calculated for each pixel in an image of a slab. The feature space is separated into 12 decision regions corresponding to 12 'defect types'; these 'defects' are labeled as clear wood, wavy grain, split, black knots, ingrown bark...

Three-dimensional dynamo-thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers by DQ-FD coupled

International Nuclear Information System (INIS)

Akbari Alashti, R.; Khorsand, M.

2012-01-01

Three-dimensional elastic analysis is carried out for functionally graded cylindrical shells bonded with piezoelectric layers subjected to dynamic and thermal loads. Material properties are assumed to be graded in the radial direction obeying a simple power law with constant Poisson's ratio. Two versions of differential quadrature (DQ) method coupled with the finite difference (FD) method are employed to discretize the governing differential equations in space and time domains. The convergence is studied and results of the axisymmetric loadings are verified with reported results. Effects of the grading index of material properties, thermal gradient, boundary conditions, thickness of piezoelectric layers and electric excitation on stress, displacement, electric and temperature fields are presented. Highlights: ► Dynamo-thermo-elastic analysis of an FGM shell with piezoelectric layer is carried out. ► Governing equations are solved by DQ-FD coupled. ► Effects of grading index, temperature difference and piezoelectric thickness are presented.

A practical MRI grading system for osteoarthritis of the knee: Association with Kellgren–Lawrence radiographic scores

Energy Technology Data Exchange (ETDEWEB)

Park, Hee-Jin, E-mail: parkhiji@gmail.com [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Department of Radiology, Kangwon National University School of Medicine, Baengnyeong-ro 156, Chuncheon-Si, Gangwon-Do Kangwon National University Hospital 200-722 (Korea, Republic of); Kim, Sam Soo, E-mail: samskim@kangwon.ac.kr [Department of Radiology, Kangwon National University School of Medicine, Baengnyeong-ro 156, Chuncheon-Si, Gangwon-Do Kangwon National University Hospital 200-722 (Korea, Republic of); Lee, So-Yeon, E-mail: parkhiji@kwandong.ac.kr [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Park, Noh-Hyuck, E-mail: nhpark904@kwandong.ac.kr [Department of Radiology, Myongji Hospital, Kwandong University, College of Medicine, 697-24 Hwajung-dong, Dukyang-ku, Koyang, Kyunggi 412-270 (Korea, Republic of); Park, Ji-Yeon, E-mail: zzzz3@hanmail.net [Department of Radiology, Myongji Hospital, Kwandong University, College of Medicine, 697-24 Hwajung-dong, Dukyang-ku, Koyang, Kyunggi 412-270 (Korea, Republic of); Choi, Yoon-Jung, E-mail: yoonchoi99@gmail.com [Department of Radiology, Sungkyunkwan University School of Medicine, Kangbuk Samsung Hospital, #108 Pyung-dong, Jongno-gu, Seoul 110-746 (Korea, Republic of); Jeon, Hyun-Jun, E-mail: ostrich-13@hanmail.net [Department of Occupational Medicine, Dongsan Medical Center, Keimyung University School of Medicine, 194 Dongsan-Dong, Jung-ku, Taegu (Korea, Republic of)

2013-01-15

Purpose: To propose a reproducible and constant MR grading system for osteoarthritis of the knee joint that provides high interobserver and intraoberver agreement and that does not require complicated calculation procedures. Materials and methods: This retrospective study sample included 44 men and 65 women who underwent both MRI and plain radiography of the knee at our institution. All patients were older than 50 years of age (mean 57.7) and had clinically suspected osteoarthritis of the knee. The standard of 4 grades on the MR grade scale was based mainly on cartilage injury and additional findings. Kellgren–Lawrence grades were assessed for the same patient group. The relationship between the results was determined. Statistical analyses were performed including kappa statistics, categorical regression analysis and nonparametric correlation analysis. Results: The interobserver and intraoberver agreements between the two readers in the grading of osteoarthritis were found to be almost perfect. Interobserver and intraobserver agreements were slightly lower for the MR grading system than for the Kellgren–Lawrence grading scale. The correlation between the MR grade and Kellgren–Lawrence grade was very high and did not differ with patient age. The MR grades were highly correlated with the Kellgren–Lawrence grades and showed excellent interobserver and intraobserver agreements. Conclusion: This new MR grading system for osteoarthritis of the knee joint is reproducible and may be helpful for the grading of osteoarthritis of the knee without requiring reference to plain radiography.

A practical MRI grading system for osteoarthritis of the knee: Association with Kellgren–Lawrence radiographic scores

International Nuclear Information System (INIS)

Park, Hee-Jin; Kim, Sam Soo; Lee, So-Yeon; Park, Noh-Hyuck; Park, Ji-Yeon; Choi, Yoon-Jung; Jeon, Hyun-Jun

2013-01-01

Purpose: To propose a reproducible and constant MR grading system for osteoarthritis of the knee joint that provides high interobserver and intraoberver agreement and that does not require complicated calculation procedures. Materials and methods: This retrospective study sample included 44 men and 65 women who underwent both MRI and plain radiography of the knee at our institution. All patients were older than 50 years of age (mean 57.7) and had clinically suspected osteoarthritis of the knee. The standard of 4 grades on the MR grade scale was based mainly on cartilage injury and additional findings. Kellgren–Lawrence grades were assessed for the same patient group. The relationship between the results was determined. Statistical analyses were performed including kappa statistics, categorical regression analysis and nonparametric correlation analysis. Results: The interobserver and intraoberver agreements between the two readers in the grading of osteoarthritis were found to be almost perfect. Interobserver and intraobserver agreements were slightly lower for the MR grading system than for the Kellgren–Lawrence grading scale. The correlation between the MR grade and Kellgren–Lawrence grade was very high and did not differ with patient age. The MR grades were highly correlated with the Kellgren–Lawrence grades and showed excellent interobserver and intraobserver agreements. Conclusion: This new MR grading system for osteoarthritis of the knee joint is reproducible and may be helpful for the grading of osteoarthritis of the knee without requiring reference to plain radiography

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.)

Status of material development for lifetime expansion of beryllium reflector

Energy Technology Data Exchange (ETDEWEB)

Dorn, C [Materion Brush Beryllium and Composites, California (United States); Tsuchiya, Kunihiko; Kawamura, Hiroshi [Japan Atomic Energy Agency, Oarai Research and Development Center, Oarai, Ibaraki (Japan); Hatano, Y [Univ. of Toyama, Toyama (Japan); Chakrov, P [INP-KNNC, Almaty (Kazakhstan); Kodama, M [Nippon Nuclear Fuel Development Co., Ltd., Oarai, Ibaraki (Japan)

2012-03-15

Beryllium has been used as the reflector element material in the reactor, specifically S-200F structural grade beryllium manufactured by Materion Brush Beryllium and Composites (former, Brush Wellman Inc.). As a part of the reactor upgrade, the Japan Atomic Energy Agency (JAEA) also has carried out the cooperation experiments to extend the operating lifetime of the beryllium reflector elements. It will first be necessary to determine which of the material's physical, mechanical and chemical properties will be the most influential on that choice. The irradiation testing plans to evaluate the various beryllium grades are also briefly considered and prepared. In this paper, material selection, irradiation test plan and PEI development for lifetime expansion of beryllium are described for material testing reactors. (author)

Degradation modes of nickel-base alternate waste package overpack materials

International Nuclear Information System (INIS)

Pitman, S.G.

1988-07-01

The suitability of Ti Grade 12 for waste package overpacks has been questioned because of its observed susceptibility to crevice corrosion and hydrogen-assisted crack growth. For this reason, materials have been selected for evaluation as alternatives to Ti Grade 12 for use as waste package overpacks. These alternative materials, which are based on the nickel-chromium-molybdenum (Ni-Cr-Mo) alloy system, are Inconel 625, Hastelloy C-276, and Hastelloy C-22. The degradation modes of the Ni-base alternate materials have been examined at Pacific Northwest Laboratory to determine the suitability of these materials for waste package overpack applications in a salt repository. Degradation modes investigated included general corrosion, crevice corrosion, pitting, stress-corrosion cracking, and hydrogen embrittlement

WAGNER’S GRADING OF DIABETIC FOOT LESIONS-A TERTIARY CARE EXPERIENCE

Directory of Open Access Journals (Sweden)

Krishna Mohan

2015-11-01

Full Text Available PURPOSE OF STUDY: Diabetic foot is the most common complication of diabetes. Amputation which is the end result of diabetic foot disease is associated with significant morbidity and mortality. Since it is crucial to identify those at an increased risk of diabetic foot complications, a detailed study of the natural history of diabetic foot, various clinical characteristics, according to Wagner grading of lesions, their outcome and management protocol followed in our hospital was undertaken in our hospital. AIM AND OBJECTIVE: Evaluation of diabetic foot lesions based on Wagner grading system, outcome and management protocol followed in our hospital. MATERIALS AND METHODS: A prospective study done on hundred diabetic foot patients in our own hospital over a period of one and half year. Data was obtained from a questionnaire developed to record the medical history, examination details, investigations reports, treatment details and final outcome at the end of stay. Infection was classified based on Meggitt-Wagner, classification/grading. RESULTS: Diabetic foot was very common in elderly age group (>55yrs 54% and male dominant (87%. Majority of them had diabetes for more than five years (47% and complications of diabetes were present on admission in 15% of them. Grade I(29%, Grade III (27% & Grade IV (24% lesions based on Wagner’s grading accounted for majority of diabetic foot lesions. Multiple toe disarticulation/ above knee / below knee amputation accounted for a quarter (23% of surgical interventions in our hospital. The glycemic control in most of patients was very poor with RBS>200 mg/dl (70% and glycosylated hemoglobin>7g% (74% of them. A quarter of the patients stayed for at least a month in the hospital (25%. CONCLUSION: It can be concluded that diabetic foot in various forms accounts for significant morbidity in the surgical wards. Wagner’s grade I (29% Grade III (27%, Grade IV (24% constituted majority of lesions. Factors contributing

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

Possibilities for specific utilization of material properties for an optimal part design

Science.gov (United States)

Beier, T.; Gerlach, J.; Roettger, R.; Kuhn, P.

2017-09-01

High-strength, cold-formable steels offer great potential for meeting cost and safety requirements in the automotive industry. In view of strengths of up to 1200 MPa now attainable, certain aspects need to be analysed and evaluated in advance in the development process using these materials. In addition to early assessment of crash properties, it is also highly important to adapt the forming process to match the material potential. The steel making companies have widened their portfolios of cold-rolled dual-phase steels well beyond the conventional high-strength steels. There are added new grades which offer a customized selection of high energy absorption, deformation resistance or enhanced cold-forming properties. In this article the necessary components for material modelling for finite element simulation are discussed. Additionally the required tests for material model calibration are presented and the potentials of the thyssenkrupp Steel material data base are introduced. Besides classical tensile tests at different angles to rolling direction and the forming limit curve, the hydraulic bulge test is now available for a wide range of modern steel grades. Using the conventional DP-K®60/98 and the DP-K®700Y980T with higher yield strength the method for calibrating yield locus, hardening and formability is given. With reference to the examples of an A-pillar reinforcement and different crash tests the procedure is shown how the customer can evaluate an optimal steel grade for specific requirements. Although the investigated materials have different yield strengths, no large differences in the forming process between the two steel grades can be found. However some advantages of the high-yield grade can be detected in crash performance depending on the specific boundary and loading conditions.

STABILITY OF FGM BEAM UNDER ACTION OF NON-CONSERVATIVE FORCE AND THERMAL LOADS%非保守力和热载荷作用下FGM梁的稳定性

Institute of Scientific and Technical Information of China (English)

赵凤群; 王忠民

2012-01-01

The stability of a FGM beam under the action of thermal loads and a uniformly distributed tangential follower force is analyzed.The material properties(Young’s modulus and mass density) of the beam are assumed to be varied continuously through the height direction according to a simple power-law distribution in terms of volume fraction of material constituents,and to be temperature-dependent.The temperature distribution of FGMs is assumed to be varied through the height direction following a one-dimensional steady-state heat conduction equation.The variation of Young’s modulus along the thickness of the beam for different values of graded index and temperature are calculated.The governing differential equations built on Euler-Bernoulli beam theory for the FGM beam are solved by using a WDQ method.The effect of the graded index,temperature,and follower force on vibration behaviors and stability of a simple supported non-conservative FGM beam are discussed.%研究了在热载荷和切向均布随从力作用下FGM梁的稳定性问题。假设材料常数（即弹性模量和密度）随温度及沿截面高度连续变化,且材料常数按各材料的体积分数以幂率变化,温度分布满足一维热传导方程,计算了不同梯度指标和不同温度下FGM梁的弹性模量随截面高度变化情况。基于Euler-Bernoulli梁理论,建立梁的控制微分方程,用小波微分求积法（WDQ法）求解,分析了梯度指标、温度、随从力等参数对简支FGM梁振动特性与稳定性的影响。

Mechanical and biological properties of the micro-/nano-grain functionally graded hydroxyapatite bioceramics for bone tissue engineering.

Science.gov (United States)

Zhou, Changchun; Deng, Congying; Chen, Xuening; Zhao, Xiufen; Chen, Ying; Fan, Yujiang; Zhang, Xingdong

2015-08-01

Functionally graded materials (FGM) open the promising approach for bone tissue repair. In this study, a novel functionally graded hydroxyapatite (HA) bioceramic with micrograin and nanograin structure was fabricated. Its mechanical properties were tailored by composition of micrograin and nanograin. The dynamic mechanical analysis (DMA) indicated that the graded HA ceramics had similar mechanical property compared to natural bones. Their cytocompatibility was evaluated via fluorescent microscopy and MTT colorimetric assay. The viability and proliferation of rabbit bone marrow mesenchymal stem cells (BMSCs) on ceramics indicated that this functionally graded HA ceramic had better cytocompatibility than conventional HA ceramic. This study demonstrated that functionally graded HA ceramics create suitable structures to satisfy both the mechanical and biological requirements of bone tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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

Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers by differential quadrature method

Energy Technology Data Exchange (ETDEWEB)

Alashti, R. Akbari, E-mail: raalashti@nit.ac.ir [Mechanical Engineering Department, Babol University of Technology, P.O. Box 484, Shariati Avenue, Babol (Iran, Islamic Republic of); Khorsand, M. [Mechanical Engineering Department, Babol University of Technology, P.O. Box 484, Shariati Avenue, Babol (Iran, Islamic Republic of)

2011-05-15

Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers under the effect of asymmetric thermo-electro-mechanical loads is carried out. Numerical results of displacement, stress and thermal fields are obtained using two versions of the differential quadrature methods, namely polynomial and Fourier quadrature methods. Material properties of the shell are assumed to be graded in the radial direction according to a power law but the Poisson's ratio is assumed to be constant. Shells are considered to be under the effect of the pressure loading in the form of cosine and ring pressure loads, electric potentials and temperature fields. Numerical results for various boundary conditions are obtained and the effects of the thickness of piezoelectric layers, grading index of material properties and the ratio of the thickness to the radius of the shell on these results is presented. - Highlights: > A numerical study of an FGM cylindrical shell with piezoelectric layers is made. > Governing equations are solved by two versions of differential quadrature methods. > The effect of layers thickness, grading index and geometrical ratios is presented.

Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers by differential quadrature method

International Nuclear Information System (INIS)

Alashti, R. Akbari; Khorsand, M.

2011-01-01

Three-dimensional thermo-elastic analysis of a functionally graded cylindrical shell with piezoelectric layers under the effect of asymmetric thermo-electro-mechanical loads is carried out. Numerical results of displacement, stress and thermal fields are obtained using two versions of the differential quadrature methods, namely polynomial and Fourier quadrature methods. Material properties of the shell are assumed to be graded in the radial direction according to a power law but the Poisson's ratio is assumed to be constant. Shells are considered to be under the effect of the pressure loading in the form of cosine and ring pressure loads, electric potentials and temperature fields. Numerical results for various boundary conditions are obtained and the effects of the thickness of piezoelectric layers, grading index of material properties and the ratio of the thickness to the radius of the shell on these results is presented. - Highlights: → A numerical study of an FGM cylindrical shell with piezoelectric layers is made. → Governing equations are solved by two versions of differential quadrature methods. → The effect of layers thickness, grading index and geometrical ratios is presented.

Mechanical analysis of non-uniform bi-directional functionally graded intelligent micro-beams using modified couple stress theory

Science.gov (United States)

Bakhshi Khaniki, Hossein; Rajasekaran, Sundaramoorthy

2018-05-01

This study develops a comprehensive investigation on mechanical behavior of non-uniform bi-directional functionally graded beam sensors in the framework of modified couple stress theory. Material variation is modelled through both length and thickness directions using power-law, sigmoid and exponential functions. Moreover, beam is assumed with linear, exponential and parabolic cross-section variation through the length using power-law and sigmoid varying functions. Using these assumptions, a general model for microbeams is presented and formulated by employing Hamilton’s principle. Governing equations are solved using a mixed finite element method with Lagrangian interpolation technique, Gaussian quadrature method and Wilson’s Lagrangian multiplier method. It is shown that by using bi-directional functionally graded materials in nonuniform microbeams, mechanical behavior of such structures could be affected noticeably and scale parameter has a significant effect in changing the rigidity of nonuniform bi-directional functionally graded beams.

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...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... 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....

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...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... 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....

On the path of a crack near a graded interface under large scale yielding

DEFF Research Database (Denmark)

Rashid, M. M.; Tvergaard, Viggo

2003-01-01

The trajectory of a crack lying parallel to a thin graded layer between two plastically dissimilar materials is studied using the exclusion region (ER) theory of fracture. The ER theory is a theoretical framework for surface separation within which a broad range of fracture phenomenologies can...... be represented. In the present study, the direction of crack advance is determined by maximizing the resolved normal-opening force on the near-tip region, whereas separation itself is governed by the intensity of plastic deformation near the tip. A computational study was undertaken using the ER theory....... The special-purpose finite element analysis platform accommodates arbitrary-and a priori unknown-crack trajectories. The model problem considered herein involves two plastically dissimilar, but elastically identical, materials joined by a thin, graded interface layer. The initial crack lies parallel...

Study on material attractiveness aspect of spent nuclear fuel of LWR and FBR cycles based on isotopic plutonium production

International Nuclear Information System (INIS)

Permana, Sidik; Suzuki, Mitsutoshi; Saito, Masaki; Novitrian,; Waris, Abdul; Suud, Zaki

2013-01-01

Highlights: • The paper analyzes the plutonium production of recycling nuclear fuel option. • To evaluate material attractiveness based on intrinsic feature of material barrier. • Evaluation based on isotopic plutonium composition of spent fuel LWR and FBR. • Even mass number of plutonium gives a significant contribution to material barrier, in particular Pu-238 and Pu-240. • Doping MA in FBR blanket is effective to increase material barrier from weapon grade plutonium to more than MOX fuel grade. - Abstract: Recycling minor actinide (MA) as well as used uranium and plutonium can be considered to reduce nuclear waste production as well as to increase the intrinsic aspect of nuclear nonproliferation as doping material. Plutonium production as a significant aspect of recycling nuclear fuel option, gives some advantages and challenges, such as fissile material utilization of plutonium as well as production of some even mass number plutonium. The study intends to evaluate the material attractiveness based on the intrinsic feature of material barrier such as plutonium composition, decay heat and spontaneous fission neutron components from spent fuel (SF) light water reactor (LWR) and fast breeder reactor (FBR) cycles. A significant contribution has been shown by decay heat (DH) and spontaneous fission neutron (SFN) of even mass number of plutonium isotopes to the total DH and SFN of plutonium element, in particular from isotopic plutonium Pu-238 and Pu-240 contributions. Longer decay cooling time and higher burnup are effective to increase the material barrier (DH and SFN) level from reactor grade plutonium level to MOX grade plutonium level. Material barrier of plutonium element from spent fuel (SF) FBR in the core regions has similarity to the material barrier profile of SF LWR which can be categorized as MOX fuel grade plutonium. Plutonium compositions, DH and SFN components are categorized as weapon grade plutonium level for FBR blanket regions with no

Fracture toughness testing of a reactor grade graphite

Energy Technology Data Exchange (ETDEWEB)

Roeding, M.; Klein, G.; Schiffers, H.; Nickel, H.

1976-03-15

Fracture mechanics is a well established tool for the assessment of brittle fracture in metallic structural materials. In this paper an attempt is made to apply fracture mechanics to a reactor-grade graphite. The effect of several test parameters on the stress intensity factor was measured; this was found to lie in the range 25 and 50 N/mm/sup -3/2/. The results are discussed in terms of the well known mechanical characteristics of graphite.

Reactor core materials research and integrated material database establishment

International Nuclear Information System (INIS)

Ryu, Woo Seog; Jang, J. S.; Kim, D. W.

2002-03-01

Mainly two research areas were covered in this project. One is to establish the integrated database of nuclear materials, and the other is to study the behavior of reactor core materials, which are usually under the most severe condition in the operating plants. During the stage I of the project (for three years since 1999) in- and out of reactor properties of stainless steel, the major structural material for the core structures of PWR (Pressurized Water Reactor), were evaluated and specification of nuclear grade material was established. And the damaged core components from domestic power plants, e.g. orifice of CVCS, support pin of CRGT, etc. were investigated and the causes were revealed. To acquire more resistant materials to the nuclear environments, development of the alternative alloys was also conducted. For the integrated DB establishment, a task force team was set up including director of nuclear materials technology team, and projector leaders and relevant members from each project. The DB is now opened in public through the Internet

Numerical Simulation for Mechanical Behavior of Asphalt Pavement with Graded Aggregate Base

Directory of Open Access Journals (Sweden)

Dongliang He

2018-01-01

Full Text Available The performance of asphalt pavement is determined by the combination of its material properties, road structure, and loading configurations. A DEM numerical simulation study was conducted to determine stress distribution and deformation behavior of asphalt pavement with graded aggregate base under standard traffic loading. Stress contour and displacement contour were presented via a self-made program. Compressive stress concentrated area located in both sides of wheel, while tensile stress concentrated area appeared in lower part of the asphalt layer. The traffic loading transferred downward by graded aggregate base and to both sides at the same time, and has a trend to expand gradually with increasing depth within graded aggregate base. Therefore, stress was well distributed in the subgrade soil layer with a great action scope, and the value decreased obviously because of the stress dispersion of graded aggregate base. Vertical displacement was the main displacement of the asphalt layer, and on the both sides of traffic loading, displacement was downward and inclined slightly to the central of loading. Vertical and horizontal deformations included in both graded aggregate base layers, and displacement extended to both sides gradually with increasing depth corresponding to stress-distribution trends. Vertical displacement was dominated in the subgrade soil layer which was relatively small.

Weldability and microstructural analysis of nuclear-grade austenitic stainless steels

International Nuclear Information System (INIS)

Lee, C.H.

1988-01-01

This study evaluated the hot-ductility response, and hot-cracking susceptibility (fusion-zone solidification cracking and HAZ liquation cracking) of modified nuclear-grade and standard austenitic stainless steels. Extensive microstructural characterization using state-of-the-art analytical electron microscopy (TEM and STEM) as well as SEM (EDAX) and OLM was performed to correlate the material behavior with metallurgical characteristics. In addition, studies of the effect of Si, N, and rare earth elements on hot-cracking susceptibility, significance of the ductility dip phenomena and backfilled solidification cracks were also performed. Furthermore, based on the metallurgical evaluation, the possible mechanisms involved in solidification cracking and HAZ liquation cracking of the modified alloys are proposed. Finally, the optimized chemical specifications and requirements for nuclear-grade stainless steels are also suggested

An Evaluation of Grades 9 and 10 Mathematics Textbooks Vis-À-Vis ...

African Journals Online (AJOL)

An Evaluation of Grades 9 and 10 Mathematics Textbooks Vis-À-Vis Fostering Problem Solving Skills. ... Document analysis was carried out on the two textbooks using Mathematics Material Analysis Instrument (MMAI) developed by Karen (1997). Interview was held with two experts from Institute of Curriculum Development ...

Functionally graded Nylon-11/silica nanocomposites produced by selective laser sintering

International Nuclear Information System (INIS)

Chung, Haseung; Das, Suman

2008-01-01

Selective laser sintering (SLS), a layered manufacturing-based freeform fabrication approach was explored for constructing three-dimensional structures in functionally graded polymer nanocomposites. Here, we report on the processing and properties of functionally graded polymer nanocomposites of Nylon-11 filled with 0-10% by volume of 15 nm fumed silica nanoparticles. SLS processing parameters for the different compositions were developed by design of experiments (DOE). The densities and micro/nanostructures of the nanocomposites were examined by optical microscopy and transmission electron microscopy (TEM). The tensile and compressive properties for each composition were then tested. These properties exhibit a nonlinear variation as a function of filler volume fraction. Finally, two component designs exhibiting a one-dimensional polymer nanocomposite material gradient were fabricated. The results indicate that particulate-filled functionally graded polymer nanocomposites exhibiting a one-dimensional composition gradient can be successfully processed by SLS to produce three-dimensional components with spatially varying mechanical properties

Beginning German in Grade Three: MLA Teacher's Guide. A Course of Study Including Methods, Materials, and Aids for Teaching Conversational German to Third-Grade Children.

Science.gov (United States)

Wittman, Nora E.; And Others

This guide is planned to help the FLES teacher develop pleasurable language learning experiences in spoken German for children at the third-grade level. Experiences included in this guide present German in life situations, as well as insight into German culture. The guide offers suggestions for classroom procedures, and detailed directions are…

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)

Movement Coordination: Factor Structure of Development in 5th-7th Grade Girls

Directory of Open Access Journals (Sweden)

O. Ivashchenko

2018-03-01

Full Text Available The study objective is to determine the structure of coordination abilities development in 5th-7th grade girls. Materials and methods. The participants in the study were 5th grade girls (n = 20, 6th grade girls (n = 23, 7th grade girls (n = 19. The study used the following methods: analysis and collation of scientific and methodological literature, general scientific methods of theoretical level, such as analogy, analysis, synthesis, abstraction, induction, as well as general scientific methods of empirical level: observation, testing, experiment. To evaluate motor preparedness, the study recorded the results of motor tests, body height and weight. The IBM SPSS 20 statistical analysis software was used to process the study materials. A factor analysis was performed, for which the study used principal component analysis with the rotation method: Variamax with Kaiser Normalization. Results. The analysis of similarities shows that the most informative tests in the structure of motor preparedness of the 5th grade girls are the following: test 11 “Evaluation of the ability for vestibular (statokinetic stability. Running with turns” (.884, test 9 “Static equilibrium evaluation by E. Ya. Bondarevsky’s method” (.826, test 6 “Evaluation of the sense of movement speed in sprinting” (.824; of the 6th grade girls — test 11 “Evaluation of the ability for vestibular (statokinetic stability. Running with turns” (0.884, test 9 “Static equilibrium evaluation by E. Ya. Bondarevsky’s method” (.826, test 6 “Evaluation of the sense of movement speed in sprinting” (.824; of the 7th grade girls — test 8 “Evaluation of the ability to differentiate movement speed (reproduction accuracy of running speed at 90% intensity of maximum” (.902, test 11 “Evaluation of the ability for vestibular (statokinetic stability. Running with turns” (.900, test 1 “30 m running (s” (.869. Conclusions. In the structure of

Grading Scale of Radiographic Findings in the Pubic Bone and Symphysis in Athletes

International Nuclear Information System (INIS)

Besjakov, J.; Scheele, C. von; Ekberg, O.; Gentz, C. F.; Westlin, N.E.

2003-01-01

Purpose: Radiographic abnormalities in the pubic bone and symphysis are often seen in athletes with groin pain. The aim was to create a grading scale of such radiologic changes. Material and Methods: Plain radiography of the pelvic ring including the pubic bone and the symphysis was performed in 20 male athletes, age 19-35, with long-standing uni- or bilateral groin pain. We used two control groups: Control group 1: 20 healthy age-matched men who had undergone radiologic examination of the pelvis due to trauma. Control group 2: 120 adults (66 men and 54 women) in 9 age groups between 15 and 90 years of age. These examinations were also evaluated for interobserver variance. Results and Conclusion: The grading scale was based on the type and the amount of the different changes, which were classified as follows: No bone changes (grade 0), slight bone changes (grade 1), intermediate changes (grade 2), and advanced changes (grade 3). The grading scale is easy to interpret and an otherwise troublesome communication between the radiologist and the physician was avoided. There was a high interobserver agreement with a high kappa value (0.8707). Male athletes with long-standing groin pain had abnormal bone changes in the symphysis significantly more frequently and more severely (p>0.001) than their age-matched references. In asymptomatic individuals such abnormalities increased in frequency with age both in men and women

Magnetothermoelastic creep analysis of functionally graded cylinders

International Nuclear Information System (INIS)

Loghman, A.; Ghorbanpour Arani, A.; Amir, S.; Vajedi, A.

2010-01-01

This paper describes time-dependent creep stress redistribution analysis of a thick-walled FGM cylinder placed in uniform magnetic and temperature fields and subjected to an internal pressure. The material creep, magnetic and mechanical properties through the radial graded direction are assumed to obey the simple power law variation. Total strains are assumed to be the sum of elastic, thermal and creep strains. Creep strains are time, temperature and stress dependent. Using equations of equilibrium, stress-strain and strain-displacement a differential equation, containing creep strains, for displacement is obtained. Ignoring creep strains in this differential equation a closed form solution for the displacement and initial magnetothermoelastic stresses at zero time is presented. Initial magnetothermoelastic stresses are illustrated for different material properties. Using Prandtl-Reuss relation in conjunction with the above differential equation and the Norton's law for the material uniaxial creep constitutive model, the radial displacement rate is obtained and then the radial and circumferential creep stress rates are calculated. Creep stress rates are plotted against dimensionless radius for different material properties. Using creep stress rates, stress redistributions are calculated iteratively using magnetothermoelastic stresses as initial values for stress redistributions. It has been found that radial stress redistributions are not significant for different material properties, however major redistributions occur for circumferential and effective stresses.

Optimization of graded multilayer designs for astronomical x-ray telescopes

DEFF Research Database (Denmark)

Mao, P.H.; Harrison, F.A.; Windt, D.L.

1999-01-01

We developed a systematic method for optimizing the design of depth-graded multilayers for astronomical hard-x-ray and soft-gamma-ray telescopes based on the instrument's bandpass and the field of view. We apply these methods to the design of the conical-approximation Wolter I optics employed...... by the balloon-borne High Energy Focusing Telescope, using W/Si as the multilayer materials. In addition, we present optimized performance calculations of mirrors, using other material pairs that are capable of extending performance to photon energies above the W K-absorption edge (69.5 keV), including Pt/C, Ni...

The Relationship of Grade Span in 9th Grade to Math Achievement in High School

Science.gov (United States)

West, John; Miller, Mary Lou; Myers, Jim; Norton, Timothy

2015-01-01

Purpose, Scope, and Method of Study: The purpose of this study was to determine if a correlation exists between grade span for ninth grade and gains in math achievement test scores in 10th grade and 12th grade. A quantitative, longitudinal, correlational research design was employed to investigate the research questions. The population was high…

Comparing Dropout Predictors for Two State-Level Panels Using Grade 6 and Grade 8 Data

Science.gov (United States)

Franklin, Bobby J.; Trouard, Stephen B.

2016-01-01

The purpose of this study was to examine the effectiveness of dropout predictors across time. Two state-level high school graduation panels were selected to begin with the seventh and ninth grades but end at the same time. The first panel (seventh grade) contained 29,554 students and used sixth grade predictors. The second panel (ninth grade)…

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

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

Thermal emission characteristics of a graded index semitransparent medium

International Nuclear Information System (INIS)

Huang Yong; Dong Sujun; Yang Min; Wang Jun

2008-01-01

This paper develops a numerical model for thermal radiative transfer in a two-dimensional semitransparent graded index medium. A piecewise continuous refractive index model, the linear refractive index bar model, is presented. This model is established based on three hypotheses, and has a higher precision than the bar model used previously. This paper also studies the thermal emission from a two-dimensional graded index medium, which is scattering or non-scattering. We find that it can present an obvious pattern of directional distribution at times. The refractive index distribution and absorption coefficient are the two main influential factors. This finding differs from the common belief that thermal sources, such as the incandescent filament of a light bulb, emit a quasi-isotropic light. The finding also suggests that there maybe other important applications of artificial GRIN materials

Functional grading of mineral and collagen in the attachment of tendon to bone.

Science.gov (United States)

Genin, Guy M; Kent, Alistair; Birman, Victor; Wopenka, Brigitte; Pasteris, Jill D; Marquez, Pablo J; Thomopoulos, Stavros

2009-08-19

Attachment of dissimilar materials is a major challenge because high levels of localized stress may develop at their interfaces. An effective biologic solution to this problem exists at one of nature's most extreme interfaces: the attachment of tendon (a compliant, structural "soft tissue") to bone (a stiff, structural "hard tissue"). The goal of our study was to develop biomechanical models to describe how the tendon-to-bone insertion derives its mechanical properties. We examined the tendon-to-bone insertion and found two factors that give the tendon-to-bone transition a unique grading in mechanical properties: 1), a gradation in mineral concentration, measured by Raman spectroscopy; and 2), a gradation in collagen fiber orientation, measured by polarized light microscopy. Our measurements motivate a new physiological picture of the tissue that achieves this transition, the tendon-to-bone insertion, as a continuous, functionally graded material. Our biomechanical model suggests that the experimentally observed increase in mineral accumulation within collagen fibers can provide significant stiffening of the partially mineralized fibers, but only for concentrations of mineral above a "percolation threshold" corresponding to formation of a mechanically continuous mineral network within each collagen fiber (e.g., the case of mineral connectivity extending from one end of the fiber to the other). Increasing dispersion in the orientation distribution of collagen fibers from tendon to bone is a second major determinant of tissue stiffness. The combination of these two factors may explain the nonmonotonic variation of stiffness over the length of the tendon-to-bone insertion reported previously. Our models explain how tendon-to-bone attachment is achieved through a functionally graded material composition, and provide targets for tissue engineered surgical interventions and biomimetic material interfaces.

7 CFR 810.804 - Grades and grade requirements for mixed grain.

Science.gov (United States)

2010-01-01

... 7 Agriculture 7 2010-01-01 2010-01-01 false Grades and grade requirements for mixed grain. 810.804 Section 810.804 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS AND STOCKYARD ADMINISTRATION (FEDERAL GRAIN INSPECTION SERVICE), DEPARTMENT OF AGRICULTURE...

Comparison of ion irradiation damage in three grades of unalloyed molybdenum

International Nuclear Information System (INIS)

Bradley, E.R.

1976-01-01

Transmission electron microscopy has been employed to characterize the ion irradiation damage in three grades of unalloyed molybdenum. The materials were irradiated with 5 MeV Ni 2+ ions at temperatures of 900 and 1000 0 C. Major differences exist in both the void and dislocation components of the damage and are attributed to differences in the carbon content of the three materials. A model, whereby carbon atoms segregate to small loops and decrease the bias for self interstitials, is used to qualitatively explain the observed variations in microstructure

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…

Functionally Graded Ceramics Fabricated with Side-by-Side Tape Casting for Use in Magnetic Refrigeration

DEFF Research Database (Denmark)

Bulatova, Regina; Bahl, Christian; Andersen, Kjeld Bøhm

2015-01-01

Functionally graded ceramic tapes have been fabricated by a side-by-side tape casting technique. This study shows the possibility and describes the main principles of adjacent coflow of slurries resulting in formation of thin plates of graded ceramic material. Results showed that the small...... variations of solvent and binder system concentrations have a substantial effect on slurry viscosity. Varying these parameters showed that side-by-side tape casting with a well-defined interface area is possible for slurries with viscosities above 3500 mPa s at a casting shear rate of 3.3 s -1...... of developing this graded ceramic tape casting was applications of these specific magnetocaloric properties within the magnetic refrigeration technology....

Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Giannitelli, S.M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Basoli, F. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy); Mozetic, P. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Piva, P.; Bartuli, F.N.; Luciani, F. [University of Rome “Tor Vergata”, Rome (Italy); Arcuri, C. [Department of Periodontics, University of Rome “Tor Vergata”, Rome (Italy); U.O.C.C. Odontostomatology, “S. Giovanni Calibita, Fatebenefratelli” Hospital, Rome (Italy); Trombetta, M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Rainer, A., E-mail: a.rainer@unicampus.it [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Licoccia, S. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy)

2015-06-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion.

Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

International Nuclear Information System (INIS)

Giannitelli, S.M.; Basoli, F.; Mozetic, P.; Piva, P.; Bartuli, F.N.; Luciani, F.; Arcuri, C.; Trombetta, M.; Rainer, A.; Licoccia, S.

2015-01-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion

Smartphone-based grading of apple quality

Science.gov (United States)

Li, Xianglin; Li, Ting

2018-02-01

Apple quality grading is a critical issue in apple industry which is one economical pillar of many countries. Artificial grading is inefficient and of poor accuracy. Here we proposed to develop a portable, convenient, real-time, and low cost method aimed at grading apple. Color images of the apples were collected with a smartphone and the grade of sampled apple was assessed by a customized smartphone app, which offered the functions translating RGB color values of the apple to color grade and translating the edge of apple image to weight grade. The algorithms are based on modeling with a large number of apple image at different grades. The apple grade data evaluated by the smartphone are in accordance with the actual data. This study demonstrated the potential of smart phone in apple quality grading/online monitoring at gathering and transportation stage for apple industry.

Evaluation of internet-based patient education materials from internal medicine subspecialty organizations: will patients understand them?

Science.gov (United States)

Hansberry, David R; Agarwal, Nitin; John, Elizabeth S; John, Ann M; Agarwal, Prateek; Reynolds, James C; Baker, Stephen R

2017-06-01

The majority of Americans use the Internet daily, if not more often, and many search online for health information to better understand a diagnosis they have been given or to research treatment options. The average American reads at an eighth-grade level. The purpose of this study is to evaluate the readability of online patient education materials on the websites of 14 professional organizations representing the major internal medicine subspecialties. We used ten well-established quantitative readability scales to assess written text from patient education materials published on the websites of the major professional organizations representing the following subspecialty groups: allergy and immunology, cardiology, endocrinology, gastroenterology, geriatrics, hematology, hospice and palliative care, infectious disease, nephrology, oncology, pulmonology and critical care, rheumatology, sleep medicine, and sports medicine. Collectively the 540 articles analyzed were written at an 11th-grade level (SD 1.4 grade levels). The sleep medicine and nephrology websites had the most readable materials, written at an academic grade level of 8.5 ± 1.5 and 9.0 ± 0.2, respectively. Material at the infectious disease site was written at the most difficult level, with average readability corresponding to grades 13.9 ± 0.3. None of the patient education materials we reviewed conformed to the American Medical Association (AMA) and the National Institutes of Health (NIH) guidelines requiring that patient education articles be written at a third- to seventh-grade reading level. If these online resources were rewritten, it is likely that more patients would derive benefit from reading them.

Cognitive impairments in patients with low grade gliomas and high grade gliomas

Directory of Open Access Journals (Sweden)

Eliane C. Miotto

2011-08-01

Full Text Available OBJECTIVE: The relationship between brain tumors and cognitive deficits is well established in the literature. However, studies investigating the cognitive status in low and high-grade gliomas patients are scarce, particularly in patients with average or lower educational level. This study aimed at investigating the cognitive functioning in a sample of patients with low and high-grade gliomas before surgical intervention. METHOD: The low-grade (G1, n=19 and high-grade glioma (G2, n=8 patients underwent a detailed neuropsychological assessment of memory, executive functions, visuo-perceptive and visuo-spatial abilities, intellectual level and language. RESULTS: There was a significant impairment on verbal and visual episodic memory, executive functions including mental flexibility, nominal and categorical verbal fluency and speed of information processing in G2. G1 showed only specific deficits on verbal and visual memory recall, mental flexibility and processing speed. CONCLUSION: These findings demonstrated different levels of impairments in the executive and memory domains in patients with low and high grade gliomas.

Influence of Rock Properties on Wear of M and SR Grade Rubber with Varying Normal Load and Sliding Speed

Directory of Open Access Journals (Sweden)

Pal Samir Kumar

2017-09-01

Full Text Available Rubbers are interesting materials and are extensively used in many mining industries for material transportation. Wear of rubber is a very complex phenomenon to understand. The present study aims to explain the influence of rock properties on wear of M and SR grade rubber used in top cover of conveyor belts. Extensive laboratory experiments were conducted under four combinations of normal load and sliding speed. The wear of both the rubber types were analyzed based on the rock properties like shear strength, abrasivity index and fractal dimension. A fully instrumented testing set up was used to study the wear of rubber samples under different operating conditions. In general, wear was higher for M grade rubber compared to SR grade rubber. Increase in shear strength of rocks depicts decreasing trend for the wear of M and SR grade rubber at lower load conditions. Moreover, a higher load combination displays no definite trend in both the rubbers. The strong correlation between the wear of rubber and frictional power for all rubber-rock combinations has given rise to the parameter A, which reflects the relative compatibility between the rubber and rock. Increase of Cerchar’s Abrasivity Index of rocks shows gradual enhancement in wear for M grade rubber in all the load and speed combinations whereas, it fails in SR grade rubber due to its higher strength. The wear of rubber tends to decrease marginally with the surface roughness of rocks at highest normal load and sliding speed in M grade rubber. However, the wear of M and SR grade rubber is influenced by the surface roughness of rocks.

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)

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.

Comparative thermal cyclic test of different beryllium grades previously subjected to simulated disruption loads

International Nuclear Information System (INIS)

Gervash, A.; Giniyatulin, R.; Mazul, I.

1999-01-01

Considering beryllium as plasma facing armour this paper presents recent results obtained in Russia. A special process of joining beryllium to a Cu-alloy material structure is described and recent results of thermal cycling tests of such joints are presented. Summarizing the results, the authors show that a Cu-alloy heat sink structure armoured with beryllium can survive high heat fluxes (≥10 MW/m 2 ) during 1000 heating/cooling cycles without serious damage to the armour material and its joint. The principal feasibility of thermal cycling of beryllium grades and their joints directly in the core of a nuclear reactor is demonstrated and the main results of this test are presented. The paper also describes the thermal cycling of different beryllium grades having cracks initiated by previously applied high heat loads simulating plasma disruptions. (orig.)

Microstructure and kinetics of a functionally graded NiTi-TiC x composite produced by combustion synthesis

International Nuclear Information System (INIS)

Burkes, Douglas E.; Moore, John J.

2007-01-01

Production of a NiTi-TiC x functionally graded material (FGM) composite is possible through use of a combustion synthesis (CS) reaction employing the propagating mode (SHS). The NiTi-TiC x FGM combines the well-known and understood superelastic and shape memory capabilities of NiTi with the high hardness, wear and corrosion resistance of TiC x . The material layers were observed as functionally graded both in composition and porosity with distinct interfaces, while still maintaining good material interaction and bonding. XRD of the FGM composite revealed the presence of TiC x with equi-atomic NiTi and minor NiTi 2 and NiTi 3 phases. The TiC x particle size decreased with increasing NiTi content. Microindentation performed across the length of the FGM revealed a decrease in hardness as the NiTi content increased

FY17 Status Report on the Micromechanical Finite Element Modeling of Creep Fracture of Grade 91 Steel

Energy Technology Data Exchange (ETDEWEB)

Messner, M. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Truster, T. J. [Univ. of Tennessee, Knoxville, TN (United States); Cochran, K. B. [DR& C Inc.; Parks, D. M. [DR& C Inc.; Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-09-01

Advanced reactors designed to operate at higher temperatures than current light water reactors require structural materials with high creep strength and creep-fatigue resistance to achieve long design lives. Grade 91 is a ferritic/martensitic steel designed for long creep life at elevated temperatures. It has been selected as a candidate material for sodium fast reactor intermediate heat exchangers and other advanced reactor structural components. This report focuses on the creep deformation and rupture life of Grade 91 steel. The time required to complete an experiment limits the availability of long-life creep data for Grade 91 and other structural materials. Design methods often extrapolate the available shorter-term experimental data to longer design lives. However, extrapolation methods tacitly assume the underlying material mechanisms causing creep for long-life/low-stress conditions are the same as the mechanisms controlling creep in the short-life/high-stress experiments. A change in mechanism for long-term creep could cause design methods based on extrapolation to be non-conservative. The goal for physically-based microstructural models is to accurately predict material response in experimentally-inaccessible regions of design space. An accurate physically-based model for creep represents all the material mechanisms that contribute to creep deformation and damage and predicts the relative influence of each mechanism, which changes with loading conditions. Ideally, the individual mechanism models adhere to the material physics and not an empirical calibration to experimental data and so the model remains predictive for a wider range of loading conditions. This report describes such a physically-based microstructural model for Grade 91 at 600° C. The model explicitly represents competing dislocation and diffusional mechanisms in both the grain bulk and grain boundaries. The model accurately recovers the available experimental creep curves at higher stresses

Direct laser metal sintering as a new approach to fabrication of an isoelastic functionally graded material for manufacture of porous titanium dental implants.

Science.gov (United States)

Traini, T; Mangano, C; Sammons, R L; Mangano, F; Macchi, A; Piattelli, A

2008-11-01

This work focuses on a titanium alloy implants incorporating a gradient of porosity, from the inner core to the outer surface, obtained by laser sintering of metal powder. Surface appearance, microstructure, composition, mechanical properties and fractography were evaluated. All the specimens were prepared by a selective laser sintering procedure using a Ti-6Al-4V alloy powder with a particle size of 1-10 microm. The morphological and chemical analyses were performed by SEM and energy dispersive X-ray spectroscopy. The flexure strength was determined by a three-point bend test using a universal testing machine. The surface roughness was investigated using a confocal scanning laser microscope. The surface roughness variation was statistically evaluated by use of a Chi square test. A p value of metal core consisted of columnar beta grains with alpha and beta laths within the grains. The alloy was composed of 90.08% Ti, 5.67% Al and 4.25% V. The Young's modulus of the inner core material was 104+/-7.7 GPa; while that of the outer porous material was 77+/-3.5 GPa. The fracture face showed a dimpled appearance typical of ductile fracture. In conclusion, laser metal sintering proved to be an efficient means of construction of dental implants with a functionally graded material which is better adapted to the elastic properties of the bone. Such implants should minimize stress shielding effects and improve long-term performance.

Heat treatments in a conventional steel to reproduce the microstructure of a nuclear grade steel

International Nuclear Information System (INIS)

Rosalio G, M.

2014-01-01

The ferritic steels used in the manufacture of pressurized vessels of Boiling Water Reactors (BWR) suffer degradation in their mechanical properties due to damage caused by the neutron fluxes of high energy bigger to a Mega electron volt (E> 1 MeV) generated in the reactor core. The materials with which the pressurized vessels of nuclear reactors cooled by light water are built correspond to low alloy ferritic steels. The effect of neutron irradiation on these steels is manifested as an increase in hardness, mechanical strength, with the consequent decrease in ductility, fracture toughness and an increase in temperature of ductile-brittle transition. The life of a BWR is 40 years, its design must be considered sufficient margin of safety because pressure forces experienced during operation, maintenance and testing of postulated accident conditions. It is necessary that under these conditions the vessel to behave ductile and likely to propagate a fracture is minimized. The vessels of light water nuclear reactors have a bainite microstructure. Specifically, the reactor vessels of the nuclear power plant of Laguna Verde (Veracruz, Mexico) are made of a steel Astm A-533, Grade B Class 1. At present they are carrying out some welding tests for the construction of a model of a BWR, however, to use nuclear grade steel such as Astm A-533 to carry out some of the welding tests, is very expensive; perform these in a conventional material provides basic information. Although the microstructure present in the conventional material does not correspond exactly to the degree of nuclear material, it can take of reference. Therefore, it is proposed to conduct a pilot study to establish the thermal treatment that reproduces the microstructure of nuclear grade steel, in conventional steel. The resulting properties of the conventional steel samples will be compared to a JRQ steel, that is a steel Astm A-533, Grade B Class 1, provided by IAEA. (Author)

Bio-inspired composites with functionally graded platelets exhibit enhanced stiffness.

Science.gov (United States)

Tapse, Sanjay; S, Anup

2017-11-09

Unidirectional composites inspired from biological materials such as nacre, are composed of stiff platelets arranged in a staggered manner within a soft matrix. Elaborate analyses have been conducted on the aforementioned composites and they are found to have excellent mechanical properties like stiffness, strength and fracture toughness. The superior properties exhibited by these composites have been proved to be the result of its unique structure. An emerging development in the field of composite structures is Functionally Graded Composites(FGC), whose properties vary spatially and possess enhanced thermo-mechanical properties. In this paper, the platelets are functionally graded with its Young's Modulus varying parabolically along the length. Two different models - namely, Tension Shear Chain Model and Minimisation of Complementary Energy Model have been employed to obtain the stiffness of the overall composite analytically. The effect of various parameters that define the composite model such as overlapping length between any two neighbouring platelets, different gradation parameters and platelet aspect ratio on the overall mechanical properties have been studied. Composites with functionally graded platelets are found to possess enhanced stiffness (upto 14% higher) for certain values of these parameters. The obtained solutions have been validated using Finite Element Analysis. Bio-inspired composites with functionally graded platelets can be engineered for structural applications, such as in automobile, aerospace and aircraft industry, where stiffness plays a crucial role. © 2017 IOP Publishing Ltd.

Youth Solid Waste Educational Materials List, November 1991.

Science.gov (United States)

Cornell Univ., Ithaca, NY. Cooperative Extension Service.

This guide provides a brief description and ordering information for approximately 300 educational materials for grades K-12 on the subject of solid waste. The materials cover a variety of environmental issues and actions related to solid waste management. Entries are divided into five sections including audiovisual programs, books, magazines,…

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. Amarnath. Articles written in Bulletin of Materials Science. Volume 26 Issue 4 June 2003 pp 435-439 Biomaterials. Effect of heat treatments on the hydrogen embrittlement susceptibility of API X-65 grade line-pipe steel · G Ananta Nagu Amarnath T K G Namboodhiri.

The Auto Industry. Grade Nine. Resource Unit (Unit IV). Project Social Studies.

Science.gov (United States)

Minnesota Univ., Minneapolis. Project Social Studies Curriculum Center.

Unit four of this curriculum plan for ninth grade social studies outlines a study of the automobile industry in the United States. Objectives state the desired generalizations, skills, and attitudes to be developed. A condensed outline of course content precedes expanded guidelines for teaching procedures and suggested resource materials. A…

Classroom: Efficient Grading

Science.gov (United States)

Shaw, David D.; Pease, Leonard F., III.

2014-01-01

Grading can be accelerated to make time for more effective instruction. This article presents specific time management strategies selected to decrease administrative time required of faculty and teaching assistants, including a multiple answer multiple choice interface for exams, a three-tier grading system for open ended problem solving, and a…

This paper describes farmer's perception towards potential adoption

African Journals Online (AJOL)

ademola

2013-12-23

Dec 23, 2013 ... We assessed the perception of farmers towards potential adoption of genetic modification (GM) technology for improving health, food security and agricultural productivity using a semi-structured interview. A total sample of 54 small-scale farmers participated in 6 focus group meetings (FGMs) and.

The Essence, Classification and Quality of the Different Grades of Information

Directory of Open Access Journals (Sweden)

Kun Wu

2012-09-01

Full Text Available I define information from a philosophical perspective as a category that indicates the presence of indirect existence, which is a self-display by material entities (with direct existence of the status and trajectory of that existence. In this paper, based in part on articles published only in Chinese over the last 30 years, information is shown to include three basic forms: In-itself, for-itself and regenerated information, which is constituted by the first two. Information in these three basic forms establishes the essence of information which is further developed in a fourth form—social information. Information is further characterized by the qualities of its three different grades, corresponding to these forms: The quality of first-grade information demonstrates direct objective existence and indirect objective existence; the quality of second-grade information demonstrates multiple levels of direct objective and indirect objective existence; the quality of third-grade information is that of the subjective relationships in human understanding that are encoded as information. The grounding of information in the ontological structure of the world gives it a central role in the approach to knowledge, constituting a new and necessary critique of the classical separation of the academic disciplines and the bases of modern philosophy.

Nanoindentation of Functionally Graded Polymer Nanocomposites: Assessment of the Strengthening Parameters through Experiments and Modeling

Directory of Open Access Journals (Sweden)

Tommaso eNardi

2015-08-01

Full Text Available NNanoindentation tests were carried out on the surface of polymer nanocomposites exhibiting either graded or homogeneous distributions of Fe3O4@silica core-shell nanoparticles in a photocurable polymeric matrix. The results reveal a complex interplay between graded morphology, indentation depth and calculated modulus and hardness values, which was elucidated through numerical simulations. First, it was experimentally shown how for small (1 µm indentations, large increases in modulus (up to +40% and hardness (up to +93% were obtained for graded composites with respect to their homogeneous counterparts, whereas at a larger indentation depth (20 µm the modulus and hardness of the graded and homogeneous composites did not substantially differ from each other and from those of the pure polymer. Then, through a Material Point Method approach, experimental nanoindentation tests were successfully simulated, confirming the importance of the indentation depth and of the associated plastic zone as key factors for a more accurate design of graded polymer nanocomposites whose mechanical properties are able to fulfill the requirements encountered during operational life.

7 CFR 58.332 - Segregation of raw material.

Science.gov (United States)

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Segregation of raw material. 58.332 Section 58.332... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Operations and Operating Procedures § 58.332 Segregation of raw material. The milk and cream received at the dairy plant shall meet...

Reducing the cost of S-65C grade beryllium for ITER first wall applications

International Nuclear Information System (INIS)

Kaczynski, D.; Sato, K.; Savchuk, V.V.; Shestakov, V.P.

2004-01-01

Beryllium is the current material of choice for plasma-facing components in ITER. The present design is for 10 mm thick beryllium tiles bonded to an actively cooled copper substrate. Brush Wellman grade S65C beryllium is preferred grade off beryllium for these tiles. S65C has the best resistance to low-cycle thermal fatigue than any other beryllium grad in the world. S65C grade beryllium has been successfully deployed in fusion reactors for more than two decades, most recently in the JET reactor. This paper will detail a supply chain to produce the most cost-effective S65C plasma facing components for ITER. This paper will also propose some future work too demonstrate the best technology for bonding beryllium to copper. (author)

Thermoluminescence induced by X-rays in silica materials with metallic impurities

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.; Espinosa P, M.; Salas, P.; Castano, V.M.

1999-01-01

Diverse materials of silica with Fe, Cu, Mg, and Mn impurities were synthesized by the sol-gel method, using tetraethyl orthosilicate as precursor. The materials obtained were subjected to thermal treatment at 500, 700 and 1000 Centigrade also they were irradiated with X-ray generated by a X-ray diffractometer which is installed in the ININ. The thermoluminescent signal was analysed and correlated with the type of impurities that are present in the material and with the grade of crystallinity produced by the thermal treatment in them. In according to the results obtained these materials show a thermoluminescent signal which is influenced by the crystallinity grade. It was analysed the behavior of the response for different doses, with the purpose of utilizing them to quantify very intense fields of radiation. (Author)

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.

Comparison of non-electrophoresis grade with electrophoresis grade BIS in NIPAM polymer gel preparation

Science.gov (United States)

Khodadadi, Roghayeh; Khajeali, Azim; Farajollahi, Ali Reza; Hajalioghli, Parisa; Raeisi, Noorallah

2015-01-01

Introduction:The main objective of this study was to investigate the possibility of replacing electrophoresis cross-linker with non-electrophoresis N, N′-methylenebisacrylamide (BIS) in N-isopropyl acrylamide (NIPAM) polymer gel and its possible effect on dose response. Methods: NIPAM polymer gel was prepared from non-electrophoresis grade BIS and the relaxation rate (R2) was measured by MR imaging after exposing the gel to gamma radiation from Co-60 source. To compare the response of this gel with the one that contains electrophoresis grade BIS, two sets of NIPAM gel were prepared using electrophoresis and non-electrophoresis BIS and irradiated to different gamma doses. Results: It was found that the dose–response of NIPAM gel made from the non-electrophoresis grade BIS is coincident with that of electrophoresis grade BIS. Conclusion:Taken all, it can be concluded that the non-electrophoresis grade BIS not only is a suitable alternative for the electrophoresis grade BIS but also reduces the cost of gel due to its lower price. PMID:26457250

TCGA_LowerGradeGliomas

Science.gov (United States)

TCGA researchers analyzed nearly 300 cases of diffuse low- and intermediate-grade gliomas, which together comprise lower-grade gliomas. LGGs occur mainly in adults and include astrocytomas, oligodendrogliomas and oligoastrocytomas.

Readability of online patient education materials on adult reconstruction Web sites.

Science.gov (United States)

Polishchuk, Daniil L; Hashem, Jenifer; Sabharwal, Sanjeev

2012-05-01

Recommended readability of patient education materials is sixth-grade level or lower. Readability of 212 patient education materials pertaining to adult reconstruction topics available from the American Academy of Orthopaedic Surgeons, American Association of Hip and Knee Surgeons, and 3 other specialty and private practitioner Web sites was assessed using the Flesch-Kincaid grade formula. The mean Flesch-Kincaid score was 11.1 (range, 3-26.5). Only 5 (2%) articles had a readability level of sixth grade or lower. Readability of most of the articles for patient education on adult reconstruction Web sites evaluated may be too advanced for a substantial portion of patients. Further studies are needed to assess the optimal readability level of health information on the Internet. Copyright © 2012 Elsevier Inc. All rights reserved.

7 CFR 51.304 - Combination grades.

Science.gov (United States)

2010-01-01

... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Grades of Apples Grades § 51.304 Combination grades. (a) Combinations of the above grades may...

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

Readability of Educational Materials to Support Parent Sexual Communication With Their Children and Adolescents.

Science.gov (United States)

Ballonoff Suleiman, Ahna; Lin, Jessica S; Constantine, Norman A

2016-05-01

Sexual communication is a principal means of transmitting sexual values, expectations, and knowledge from parents to their children and adolescents. Many parents seek information and guidance to support talking with their children about sex and sexuality. Parent education materials can deliver this guidance but must use appropriate readability levels to facilitate comprehension and motivation. This study appraised the readability of educational materials to support parent sexual communication with their children. Fifty brochures, pamphlets, and booklets were analyzed using the Flesch-Kincaid, Gunning Fog, and Simple Measure of Gobbledygook (SMOG) index methods. Mean readability grade-level scores were 8.3 (range = 4.5-12.8), 9.7 (range = 5.5-14.9), and 10.1 (range = 6.7-13.9), respectively. Informed by National Institutes of Health-recommended 6th to 7th grade levels and American Medical Association-recommended 5th to 6th grade levels, percentages falling at or below the 7.0 grade level were calculated as 38%, 12%, and 2% and those falling at or below the 6.0 grade level were calculated as 12%, 2%, and 0% based on the Flesch-Kincaid, Gunning Fog, and SMOG methods, respectively. These analyses indicate that the majority of educational materials available online to support parents' communication with their children about sex and sexuality do not meet the needs of many or most parents. Efforts to improve the accessibility of these materials are warranted.

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

Potential benefits of genetic modification (GM) technology for food ...

African Journals Online (AJOL)