Sample records for knoop hardness values

  1. Measurement of surface hardness of primary carious lesions in extracted human enamel -measurement of Knoop hardness using Cariotester.

    PubMed

    Shimizu, Akihiko; Yamamoto, Takatsugu; Nakashima, Syozi; Nikaido, Toru; Sugawara, Toyotaro; Momoi, Yasuko

    2015-01-01

    The clinical feasibility of a novel device called a Cariotester was investigated by measuring the Knoop hardness (KHN) of white spot lesions diagnosed as ICDAS code 1, 2 or 3. To obtain an equation for converting the Cariotester indentation depth into the KHN, a regression analysis was performed between the depth and measured KHN for human enamel. The Cariotester was then used to measure the indentation depth for white spots (ICDAS code 1, 2 or 3) in extracted teeth, and the KHN values were determined using the above equation. The KHN was 219.9±19.7, 162.4±24.0 and 31.7±17.5 for code 1, 2 and 3 lesions, respectively, which was 30, 49 and 90% lower than that for healthy enamel. Using the formula reported in the literature, the mineral density was calculated to be 87.7 vol.% for healthy enamel, and 75.1, 66.1 and 35.5 vol.% for code 1, 2 and 3 lesions, respectively. PMID:25740310

  2. Newly developed hardness testing system, "Cariotester": measurement principles and development of a program for measuring Knoop hardness of carious dentin.

    PubMed

    Shimizu, Akihiko; Nakashima, Syozi; Nikaido, Toru; Sugawara, Toyotaro; Yamamoto, Takatsugu; Momoi, Yasuko

    2013-01-01

    We previously discovered that when a cone-shaped indenter coated with paint was pressed into an object, the paint disappeared in accordance with the depth of the indentation. Based on this fact, we developed the Cariotester, a portable system for measuring the Knoop hardness (KHN) of carious dentin. The Cariotester is composed of a handpiece with an indenter, a microscope, and a computer. In this system, the painted indenter is forced into the material with a 150-gf load, and the indentation depth (CT depth) is obtained from the paint disappearance. The CT depth by the Cariotester and the KHN by a microhardness tester were determined at 14 dentin regions. From the data, a program was created to convert the CT depth of the carious dentin into the KHN. As a result, if the CT depth is measured with this system, the KHN of carious dentin can be displayed in real time. PMID:23903648

  3. Does an additional UV LED improve the degree of conversion and Knoop Hardness of light-shade composite resins?

    PubMed Central

    Giorgi, Maria Cecília Caldas; Aguiar, Flávio Henrique Baggio; Soares, Luís Eduardo Silva; Martin, Airton Abrahão; Liporoni, Priscila Christiane Suzy; Paulillo, Luís Alexandre Maffei Sartini

    2012-01-01

    Objective: The purpose of this study was to evaluate the degree of conversion (DC) using FT-Raman spectroscopy and the Knoop hardness (KHN) of composites cured by second and third-generation LED light curing-units (LCU), Radii Cal and Ultralume 5. Methods: Three composites (Filtek Supreme XT, Filtek Z350, and Esthet X) were selected for this study. KHN testing (n=10) was performed with 10 indentations for the top (T) and bottom (B) surfaces. For DC (n=10), both the T and B surfaces were analyzed. Results: For KHN, the three composites differed in hardens. There was a “LCU-surface” interaction, in which Radii Cal showed significantly greater hardens in the B surface. For DC, there was a “composite-surface-LCU” interaction. For the “composite” factor, there was no significant difference between the groups, except for Supreme XT-Radii Cal (T or B surfaces). For the “LCU” factor there was a significant difference for Supreme XT T surface, Ultralume 5 obtained a higher DC. For the Z350 T surface, a significant difference in the DC in which Radii Cal obtained better results. For the “surface” factor, all groups presented T surfaces with a higher DC than the B surfaces, the sole exceptions involved Esthet X-Radii Cal and Z350-Ultralume 5. Conclusion: Knowledge regarding composite composition and the characteristics of LCUs are important for effective polymerization. PMID:23077419

  4. Influence of different indentation load and dwell time on Knoop microhardness tests for composite materials

    Microsoft Academic Search

    Oguz Yoldas; Tolga Akova; Hakan Uysal

    2004-01-01

    Various microhardness test methods with different indentation loads and dwell times have been used to evaluate the hardness of composite materials. However, there is still no agreement on the ideal test method for composites. The aim of this study was to determine the influence of different indentation load and dwell time on Knoop Hardness Number (KHN) of three different kinds

  5. Elasticity and hardness of nano-polycrystalline boron nitrides: The apparent Hall-Petch effect

    SciTech Connect

    Nagakubo, A.; Ogi, H., E-mail: ogi@me.es.osaka-u.ac.jp; Hirao, M. [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Sumiya, H. [Advanced Materials R and D Laboratories, Sumitomo Electric Industries, Ltd., Itami, Hyogo 664-0016 (Japan)

    2014-08-25

    Nano-polycrystalline boron nitride (BN) is expected to replace diamond as a superhard and superstiff material. Although its hardening was reported, its elasticity remains unclear and the as-measured hardness could be significantly different from the true value due to the elastic recovery. In this study, we measured the longitudinal-wave elastic constant of nano-polycrystalline BNs using picosecond ultrasound spectroscopy and confirmed the elastic softening for small-grain BNs. We also measured Vickers and Knoop hardness for the same specimens and clarified the relationship between hardness and stiffness. The Vickers hardness significantly increased as the grain size decreased, while the Knoop hardness remained nearly unchanged. We attribute the apparent increase in Vickers hardness to the elastic recovery and propose a model to support this insight.

  6. Contact values for disparate-size hard-sphere mixtures

    Microsoft Academic Search

    Andres Santos; Santos B. Yuste; Mariano Lopez de Haro; Morad Alawneh; Douglas Henderson

    2009-01-01

    A universality ansatz for the contact values of a multicomponent mixture of additive hard spheres is used to propose new formulae for the case of disparate-size binary mixtures. A comparison with simulation data and with a recent proposal by Alawneh and Henderson for binary mixtures shows reasonably good agreement with the predictions for the contact values of the large-large radial

  7. Contact values for disparate-size hard-sphere mixtures

    E-print Network

    Santos, A; de Haro, M López; Alawneh, M; Henderson, D

    2009-01-01

    A universality ansatz for the contact values of a multicomponent mixture of additive hard spheres is used to propose new formulae for the case of disparate-size binary mixtures. A comparison with simulation data and with a recent proposal by Alawneh and Henderson for binary mixtures shows reasonably good agreement with the predictions for the contact values of the large-large radial distribution functions. A discussion on the usefulness and limitations of the new proposals is also presented.

  8. Contact values for disparate-size hard-sphere mixtures

    E-print Network

    A. Santos; S. B. Yuste; M. López de Haro; M. Alawneh; D. Henderson

    2009-05-22

    A universality ansatz for the contact values of a multicomponent mixture of additive hard spheres is used to propose new formulae for the case of disparate-size binary mixtures. A comparison with simulation data and with a recent proposal by Alawneh and Henderson for binary mixtures shows reasonably good agreement with the predictions for the contact values of the large-large radial distribution functions. A discussion on the usefulness and limitations of the new proposals is also presented.

  9. Determination of the Mechanical Properties of Plasma-Sprayed Hydroxyapatite Coatings Using the Knoop Indentation Technique

    NASA Astrophysics Data System (ADS)

    Hasan, Md. Fahad; Wang, James; Berndt, Christopher

    2015-06-01

    The microhardness and elastic modulus of plasma-sprayed hydroxyapatite coatings were evaluated using Knoop indentation on the cross section and on the top surface. The effects of indentation angle, testing direction, measurement location and applied load on the microhardness and elastic modulus were investigated. The variability and distribution of the microhardness and elastic modulus data were statistically analysed using the Weibull modulus distribution. The results indicate that the dependence of microhardness and elastic modulus on the indentation angle exhibits a parabolic shape. Dependence of the microhardness values on the indentation angle follows Pythagoras's theorem. The microhardness, Weibull modulus of microhardness and Weibull modulus of elastic modulus reach their maximum at the central position (175 µm) on the cross section of the coatings. The Weibull modulus of microhardness revealed similar values throughout the thickness, and the Weibull modulus of elastic modulus shows higher values on the top surface compared to the cross section.

  10. Determination of the Mechanical Properties of Plasma-Sprayed Hydroxyapatite Coatings Using the Knoop Indentation Technique

    NASA Astrophysics Data System (ADS)

    Hasan, Md. Fahad; Wang, James; Berndt, Christopher

    2015-04-01

    The microhardness and elastic modulus of plasma-sprayed hydroxyapatite coatings were evaluated using Knoop indentation on the cross section and on the top surface. The effects of indentation angle, testing direction, measurement location and applied load on the microhardness and elastic modulus were investigated. The variability and distribution of the microhardness and elastic modulus data were statistically analysed using the Weibull modulus distribution. The results indicate that the dependence of microhardness and elastic modulus on the indentation angle exhibits a parabolic shape. Dependence of the microhardness values on the indentation angle follows Pythagoras's theorem. The microhardness, Weibull modulus of microhardness and Weibull modulus of elastic modulus reach their maximum at the central position (175 µm) on the cross section of the coatings. The Weibull modulus of microhardness revealed similar values throughout the thickness, and the Weibull modulus of elastic modulus shows higher values on the top surface compared to the cross section.

  11. Traceability in hardness measurements: from the definition to industry

    NASA Astrophysics Data System (ADS)

    Germak, Alessandro; Herrmann, Konrad; Low, Samuel

    2010-04-01

    The measurement of hardness has been and continues to be of significant importance to many of the world's manufacturing industries. Conventional hardness testing is the most commonly used method for acceptance testing and production quality control of metals and metallic products. Instrumented indentation is one of the few techniques available for obtaining various property values for coatings and electronic products in the micrometre and nanometre dimensional scales. For these industries to be successful, it is critical that measurements made by suppliers and customers agree within some practical limits. To help assure this measurement agreement, a traceability chain for hardness measurement traceability from the hardness definition to industry has developed and evolved over the past 100 years, but its development has been complicated. A hardness measurement value not only requires traceability of force, length and time measurements but also requires traceability of the hardness values measured by the hardness machine. These multiple traceability paths are needed because a hardness measurement is affected by other influence parameters that are often difficult to identify, quantify and correct. This paper describes the current situation of hardness measurement traceability that exists for the conventional hardness methods (i.e. Rockwell, Brinell, Vickers and Knoop hardness) and for special-application hardness and indentation methods (i.e. elastomer, dynamic, portables and instrumented indentation).

  12. Working Hard or Hardly Working? An Exploration of the Achievement Values of African American Youth.

    ERIC Educational Resources Information Center

    Taylor, April Z.; And Others

    This study investigated African American adolescents' achievement values. One hundred and forty-six male and 161 female African American sixth graders at a middle school in the Los Angeles (California) area nominated classmates according to 3 criteria: those whom they most admired, respected, and wanted to be like. These nominations were combined…

  13. RESEARCH ARTICLE Contact values for disparate-size hard-sphere mixtures

    Microsoft Academic Search

    Andres Santos; Santos B. Yuste; Mariano Lopez de Haro; Morad Alawneh; Douglas Henderson

    A universality ansatz for the contact values of a multicomponent mixture of additive hard spheres is used to propose new formulae for the case of disparate-size binary mixtures. A comparison with simulation data and with a recent proposal by Alawneh and Henderson for binary mixtures shows reasonably good agreement with the predictions for the contact values of the large-large radial

  14. The fertilizing value of livestock waste is hardly determined considering its initial variability, the

    E-print Network

    Paris-Sud XI, Université de

    it is exchanged, manure is mainly in this form. The quantity of solid waste can be estimated with the classicalThe fertilizing value of livestock waste is hardly determined considering its initial variability measurements of liquid waste outflows and Near Infrared spectrometry technique have been implemented

  15. Molecular dynamics and theory for the contact values of the radial distribution functions of hard-disk uid mixtures

    E-print Network

    Luding, Stefan

    Molecular dynamics and theory for the contact values of the radial distribution functions of hard of the radial distribution functions of binary additive mixtures of hard disks. The simulation data are compared is measured by the radial distribution function (RDF) g ij (r; #23;; x; #27;). The contact values #31; ij (#23

  16. 443R. Bock and V. Knoop (eds.), Genomics of Chloroplasts and Mitochondria, Advances in Photosynthesis and Respiration 35, pp. 443458,

    E-print Network

    Hamel, Patrice

    443R. Bock and V. Knoop (eds.), Genomics of Chloroplasts and Mitochondria, Advances+Business Media B.V. 2012 Chapter 19 Transformation and Nucleic Acid Delivery to Mitochondria Claire Remacle and RNA Delivery into Plant Mitochondria

  17. Singular Values of Products of Ginibre Random Matrices, Multiple Orthogonal Polynomials and Hard Edge Scaling Limits

    NASA Astrophysics Data System (ADS)

    Kuijlaars, Arno B. J.; Zhang, Lun

    2014-12-01

    Akemann, Ipsen and Kieburg recently showed that the squared singular values of products of M rectangular random matrices with independent complex Gaussian entries are distributed according to a determinantal point process with a correlation kernel that can be expressed in terms of Meijer G-functions. We show that this point process can be interpreted as a multiple orthogonal polynomial ensemble. We give integral representations for the relevant multiple orthogonal polynomials and a new double contour integral for the correlation kernel, which allows us to find its scaling limits at the origin (hard edge). The limiting kernels generalize the classical Bessel kernels. For M = 2 they coincide with the scaling limits found by Bertola, Gekhtman, and Szmigielski in the Cauchy-Laguerre two-matrix model, which indicates that these kernels represent a new universality class in random matrix theory.

  18. Applying critical thinking skills to character education and values clarification with students who are deaf or hard of hearing.

    PubMed

    Easterbrooks, Susan R; Scheetz, Nanci A

    2004-01-01

    Students who are deaf or hard of hearing must learn to think critically. Character education (CE) refers to the effort to teach basic values and moral reasoning (Doyle & Ponder, 1977). Values clarification (VC) is the process of examining one's basic values and moral reasoning (Rokeach, 1973). Character education and values clarification as subject matter foster the development of critical thinking (CT), a tool used both to develop and to modify values and moral reasoning. These three areas mutually support one another. The development of a set of values and their underlying moral reasoning is the foundation for thinking critically about values. The authors examine the components of critical thinking, character education, and values clarification, summarize the literature, and provide a template for appropriate lesson plans. They also describe strategies that promote the development of critical thinking, character education, and values clarification. PMID:15552336

  19. Molecular dynamics and theory for the contact values of the radial distribution functions of hard-disk fluid mixtures

    Microsoft Academic Search

    Stefan Luding; Andrés Santos

    2004-01-01

    We report molecular dynamics results for the contact values of the radial distribution functions of binary additive mixtures of hard disks. The simulation data are compared with theoretical predictions from expressions proposed by Jenkins and Mancini [J. Appl. Mech. 54, 27 (1987)] and Santos et al. [J. Chem. Phys. 117, 5785 (2002)]. Both theories agree quantitatively within a very small

  20. Analysis of pyramid indentation of pressure-sensitive hard metals and ceramics

    Microsoft Academic Search

    A. E. Giannakopoulos; P.-L. Larsson

    1997-01-01

    In the last two decades, pyramid micro and nano-indentation tests such as Vickers (tetragonal base), Berkovich (trigonal base), and Knoop (rhomboid base) have been used on pressure sensitive materials, including hard metals, glasses and ceramics, and were found to give valuable mechanical and other physical information which may be otherwise difficult to obtain. Such indentation experiments are attractive because they

  1. Hardness, polymerization depth, and internal adaptation of Class II silorane composite restorations as a function of polymerization protocol

    PubMed Central

    Bechtold, Janaina; dos Santos, Priscila Jaques; Anido-Anido, Andrea; Di Hipólito, Vinícius; Alonso, Roberta Caroline Bruschi; D’Alpino, Paulo Henrique Perlatti

    2012-01-01

    Objectives: To evaluate the influence of various photoactivation techniques on the internal gap, Knoop-hardness, and polymerization depth of silorane- and methacrylate-based composites in Class II restorations. Methods: Preparations were made in third molars (n = 10), according to composites (Filtek P60: methacrylate; Filtek P90: silorane) and photoactivation techniques (OC: occlusal photoactivation (control); OBL: occlusal+buccal+lingual photoactivation; and BLO: buccal+lingual+occlusal photoactivation (transdental)). Composites were inserted in two increments, both individually photoactivated for 20s. After 24h, specimens were sectioned and the ratio of internal gaps to interface length (%) recorded. Hardness was tested across the transversal section of restorations (1–4 mm below the surface). Results: Silorane restorations showed significantly lower gaps compared with methacrylate, regardless of polymerization technique (P<.05). Supplementary energy dose in OBL and BLO protocols caused significant increase in gaps in silorane restorations (P<.05). For methacrylate restorations, OBL activation caused significantly higher gap formation (P<.05). Significantly lower hardness values were seen for silorane than for methacrylate composites (P<.05), regardless of depth and photoactivation. Significantly higher hardness values were seen in BLO activation for methacrylate restorations compared with control (P<.05); for silorane, no differences were observed. Significantly higher hardness values were observed at 1 and 3 mm compared to 2 and 4 mm for both composites. Conclusions: Internal gaps and hardness are affected by composite type and photoactivation. Despite the reduced values, hardness of silorane is not influenced by photoactivation or by depth. Internal gaps are dependent on the energy dose for both composites, with silorane showing lower internal gaps. PMID:22509115

  2. Computation of the Shapley Value of Minimum Cost Spanning Tree Games: #P-Hardness and

    E-print Network

    RIMS-1690 Computation of the Shapley Value of Minimum Cost Spanning Tree Games: #P UNIVERSITY, Kyoto, Japan #12;Computation of the Shapley Value of Minimum Cost Spanning Tree Games: #P minimum cost spanning tree game can be computed in O(n4) time, where n is the number of players. 1

  3. Molecular dynamics and theory for the contact values of the radial distribution functions of hard-disk fluid mixtures

    E-print Network

    Stefan Luding; Andres Santos

    2004-07-01

    We report molecular dynamics results for the contact values of the radial distribution functions of binary additive mixtures of hard disks. The simulation data are compared with theoretical predictions from expressions proposed by Jenkins and Mancini [J. Appl. Mech. \\textbf{54}, 27 (1987)] and Santos et al. [J. Chem. Phys. \\textbf{117}, 5785 (2002)]. Both theories agree quantitatively within a very small margin, which renders the former still a very useful and simple tool to work with. The latter (higher-order and self-consistent) theory provides a small qualitative correction for low densities and is superior especially in the high-density domain.

  4. Contact values of the radial distribution functions of additive hard-sphere mixtures in d dimensions: A new proposal

    E-print Network

    A. Santos; S. B. Yuste; M. Lopez de Haro

    2002-07-01

    The contact values $g_{ij}(\\sigma_{ij})$ of the radial distribution functions of a $d$-dimensional mixture of (additive) hard spheres are considered. A `universality' assumption is put forward, according to which $g_{ij}(\\sigma_{ij})=G(\\eta, z_{ij})$, where $G$ is a common function for all the mixtures of the same dimensionality, regardless of the number of components, $\\eta$ is the packing fraction of the mixture, and $z_{ij}$ is a dimensionless parameter that depends on the size distribution and the diameters of spheres $i$ and $j$. For $d=3$, this universality assumption holds for the contact values of the Percus--Yevick approximation, the Scaled Particle Theory, and, consequently, the Boublik--Grundke--Henderson--Lee--Levesque approximation. Known exact consistency conditions are used to express $G(\\eta,0)$, $G(\\eta,1)$, and $G(\\eta,2)$ in terms of the radial distribution at contact of the one-component system. Two specific proposals consistent with the above conditions (a quadratic form and a rational form) are made for the $z$-dependence of $G(\\eta,z)$. For one-dimensional systems, the proposals for the contact values reduce to the exact result. Good agreement between the predictions of the proposals and available numerical results is found for $d=2$, 3, 4, and 5.

  5. A Terrible Predicament: The De-Evolution of Values in Flannery O'Connor's "A Good Man Is Hard to Find."

    ERIC Educational Resources Information Center

    Tietz, Stephen; Logsdon, Loren

    2001-01-01

    Addresses problems concerning the ways Flannery O'Connor's fiction has been read. Proposes an alternate reading of "A Good Man Is Hard to Find." Suggests the primary theme of the story is the idea that each generation has the responsibility to pass on values to the next. (PM)

  6. Comparative evaluation of surface hardness and depth of cure of silorane and methacrylate-based posterior composite resins: An in vitro study

    PubMed Central

    Agrawal, Abhishek; Manwar, Narendra U; Hegde, Shubha G; Chandak, Manoj; Ikhar, Anuja; Patel, Aditya

    2015-01-01

    Aim: This in vitro study was carried out to compare the effect of LED light curing system on polymerization and hardness of silorane-based and methacrylate-based posterior composite resin. Materials and Methods: A total of 40 samples, 20 of silorane-based composite Filtek P-90 and 20 of methacrylate-based composite Heliomolar HB measuring 2 mm thickness and 8 mm diameter were prepared using Teflon molds and cured using LED curing light. The samples were polished and tested in Knoop hardness tester using a 50-gram load and dwell time of 15 seconds on top and bottom surfaces. The percentage depth of cure was calculated, and statistical analysis was performed using two-way ANOVA test and Student t- test. Results: Higher statistically significant values were seen for both the top and bottom surface hardness in silorane-based resins than methacrylate-based resins on LED light curing. Conclusion: Greater depth of cure was achieved in silorane-based posterior composite than in methacrylate-based posterior composite resins with a statistically significant difference. PMID:25829693

  7. A Case Study on Investigating the Effect of Genetic Algorithm Operators on Predicting the Global Minimum Hardness Value of Biomaterial Extrudate

    SciTech Connect

    Shankar, T.J. [University of British Columbia, Vancouver; Sokhansanj, Shahabaddine [ORNL

    2010-02-01

    Crossover and mutation are the main search operators of genetic algorithm, one of the most important features which distinguish it from other search algorithms like simulated annealing. A genetic algorithm adopts crossover and mutation as their main genetic operators. The present work was aimed to see the effect of genetic algorithm operators like crossover and mutation (Pc & Pm), population size (n), and number of iterations (I) on predicting the minimum hardness (N) of the biomaterial extrudate. The second order polynomial regression equation developed for the extrudate property hardness in terms of the independent variables like barrel temperature, screw speed, fish content of the feed, and feed moisture content was used as the objective function in the GA analysis. A simple genetic algorithm (SGA) with a crossover and mutation operators was used in the present study. A program was developed in C language for a SGA with a rank based fitness selection method. The upper limit of population and iterations were fixed at 100. It was observed that increasing population and iterations the prediction of function minimum improved drastically. Minimum predicted hardness values were achievable with a medium population of 50, iterations of 50 and crossover and mutation probabilities of 50 % and 0.5 %. Further the Pareto charts indicated that the effect of Pc was found to be more significant when population is 50 and Pm played a major role at low population ( 10). A crossover probability of 50 % and mutation probability of 0.5 % are the threshold values for the convergence of GA to reach a global search space. A minimum predicted hardness value of 3.82 (N) was observed for n = 60 and I = 100 and Pc & Pm of 85 % and 0.5 %.

  8. Values.

    ERIC Educational Resources Information Center

    Chapel Hill City Schools, NC.

    GRADES OR AGES: Grades 1-12. SUBJECT MATTER: Values. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is intended to define the development of the valuing process and contains ideas for classroom teachers. It is not a conventional curriculum guide but is recommended for use with the guide on drug education (SP 007 318). It contains the following…

  9. Hardness and fracture toughness of moissanite

    Microsoft Academic Search

    J. Qian; L. L. Daemen; Y. Zhao

    2005-01-01

    Disparities prevail among the reported hardness and fracture toughness values for hard and brittle materials. A better understanding of the physical nature of hardness and fracture toughness and a standardized technique for reliable measurements of these quantities is urgently needed. We strongly recommend the use of the measured hardness after the bend in the hardness versus load (H?FLoad) curve, when

  10. Ormosils of high hardness

    SciTech Connect

    Iwamoto, Takashi; Mackenzie, J.D. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering

    1994-12-31

    Organically modified silicates (ormosils) of high hardness were prepared by the reactions of tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) aided by ultrasonic irradiation. The mechanisms leading to the hard ormosil formation were investigated by liquid state {sup 29}Si NMR spectroscopy. PDMS chains were found to be broken into shorter chains and/or 4-membered siloxane rings during the reaction and finally, all PDMS chains were chemically incorporated as short chains into silica networks. Vickers hardnesses of the hard ormosils were measured and compared with those of the hardest transparent plastics. Whereas the hardest transparent plastics have Vickers hardness values of less than 25 kg/mm{sup 2}, the hard ormosils have Vickers hardnesses tip to higher than 150 kg/mm{sup 2}. A theoretical model was developed for the calculation of Vickers hardnesses of the hard ormosils and agreed well with experimental results. Predictions based on this theory indicate that even harder ormosils can be made when Al{sub 2}O{sub 3}, ZrO{sub 2} and TiO{sub 2} are substituted for SiO{sub 2}. Results based on these new ormosils are also presented.

  11. Must "Hard Problems" Be Hard?

    ERIC Educational Resources Information Center

    Kolata, Gina

    1985-01-01

    To determine how hard it is for computers to solve problems, researchers have classified groups of problems (polynomial hierarchy) according to how much time they seem to require for their solutions. A difficult and complex proof is offered which shows that a combinatorial approach (using Boolean circuits) may resolve the problem. (JN)

  12. Effect of rolling and annealing processes on the hardness and electrical conductivity values of Cu–13.5%Mn–4%Ni alloy

    Microsoft Academic Search

    Sh. Raygan; H. Ehsanian Mofrad; M. Pourabdoli; F. K. Ahadi

    2011-01-01

    It was found that the dendritic microstructure of an as-cast alloy was changed to an almost equiaxed alloy after 480min of annealing at 700°C. The electrical conductivity of as-cast and hot rolled samples increased from 27.36 and 30.51% IACS to 30.67 and 32.1% IACS after 480min of annealing at 700°C. The dendritic microstructure and the electrical conductivity values of an

  13. SUPER HARD SURFACED POLYMERS

    SciTech Connect

    Mansur, Louis K [ORNL] [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL] [ORNL; Clemons, Art [ORNL] [ORNL; Eberle, Cliff [ORNL] [ORNL; Evans, H B [UES, Incorporated, Dayton, OH] [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL] [ORNL; Jolly, Brian C [ORNL] [ORNL; Lee, E H [Consultant, Milpitas, CA] [Consultant, Milpitas, CA; Leonard, Keith J [ORNL] [ORNL; Trejo, Rosa M [ORNL] [ORNL; Rivard, John D [ORNL] [ORNL

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  14. BOOKSHELF Hard Disk Drive

    E-print Network

    Benmei, Chen

    » BOOKSHELF Hard Disk Drive Servo Systems, 2nd edition by B.M. CHEN, T.H. LEE, K. PENG, and V- widths ever higher as higher frequency disturbances become relevant. THE BOOK Hard Disk Drive Servo I of Hard Disk Drive Servo Systems briefly discusses the history of hard drive control and the disk

  15. Investigations on The Surface Properties of 4-Methoxy N-Methyl 4-Stilbazolium Tosylate Single Crystal

    NASA Astrophysics Data System (ADS)

    Gill, Amirdha Sher; Kalainathan, S.

    2011-07-01

    The mechanical properties of crystals are evaluated by mechanical testing which reveals certain surface characteristics. The fastest and simplest type of mechanical testing is hardness measurement. The Vickers and Knoop microhardness studies have been carried out on 4-methoxy benzaldehyde N-methyl 4-stilbazolium tosylate crystals grown by slow evaporation technique over a load range of 10-100 g. The Vickers hardness number (Hv) and the Knoop microhardness number (Hk) were found to increase with the increase in load. The Meyer's index number 'n' was calculated from Hv. The Young's modulus was calculated using the Knoop hardness values. Hardness anisotropy has been observed in accordance with the orientation of the crystal. Laser damage threshold studies have been carried out for the crystal using a Q-switched Nd:YAG laser of ns pulses. The surface of the grown crystal was analyzed with etching. The results are discussed in detail.

  16. Hardness testing. 2nd edition

    SciTech Connect

    Chandler, H. [ed.

    1999-07-01

    This basic book provides a comprehensive overview of hardness testing, including the various methods and equipment used, testing applications, and the selection of testing methods. The revised and updated second edition features expanded information on microhardness testing, specialized hardness tests; and hardness testing standards. Contents include: introduction to hardness testing; brinell testing; rockwell hardness testing; vickers hardness testing; microhardness testing; scleroscope and leeb hardness testing; hardness testing applications; and selection of hardness testing methods.

  17. Wear of hard materials by hard particles

    SciTech Connect

    Hawk, Jeffrey A.

    2003-10-01

    Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

  18. "We Can Get Everything We Want if We Try Hard": Young People, Celebrity, Hard Work

    ERIC Educational Resources Information Center

    Mendick, Heather; Allen, Kim; Harvey, Laura

    2015-01-01

    Drawing on 24 group interviews on celebrity with 148 students aged 14-17 across six schools, we show that "hard work" is valued by young people in England. We argue that we should not simply celebrate this investment in hard work. While it opens up successful subjectivities to previously excluded groups, it reproduces neoliberal…

  19. How Hard is Chocolate?

    NSDL National Science Digital Library

    2007-12-20

    Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

  20. Session: Hard Rock Penetration

    SciTech Connect

    Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

    1992-01-01

    This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

  1. Memory Hard Drive Peripherals

    E-print Network

    Stojmenovic, Ivan

    1! CSI3131 Topics CPU Memory Hard Drive Peripherals Computing Systems OS Overview StructureDeadlocks M em ory M anagem ent Basic Memory Managermtn Virtual Memory Storage and I/O File Systems Hard Drive Management Swap I/O Management 2 Module 7: Memory Management Reading: Chapter 8 § To provide a detailed

  2. The hard metal diseases.

    PubMed

    Cugell, D W

    1992-06-01

    Hard metal is a mixture of tungsten carbide and cobalt, to which small amounts of other metals may be added. It is widely used for industrial purposes whenever extreme hardness and high temperature resistance are needed, such as for cutting tools, oil well drilling bits, and jet engine exhaust ports. Cobalt is the component of hard metal that can be a health hazard. Respiratory diseases occur in workers exposed to cobalt--either in the production of hard metal, from machining hard metal parts, or from other sources. Adverse pulmonary reactions include asthma, hypersensitivity pneumonitis, and interstitial fibrosis. A peculiar, almost unique form of lung fibrosis, giant cell interstitial pneumonia, is closely linked with cobalt exposure. PMID:1511554

  3. Laser quench hardening of steel: Effects of superimposed elastic pre-stress on the hardness and residual stress distribution

    NASA Astrophysics Data System (ADS)

    Meserve, Justin

    Cold drawn AISI 4140 beams were LASER surface hardened with a 2 kW CO2 LASER. Specimens were treated in the free state and while restrained in a bending fixture inducing surface tensile stresses of 94 and 230 MPa. Knoop hardness indentation was used to evaluate the through thickness hardness distribution, and a layer removal methodology was used to evaluate the residual stress distribution. Results showed the maximum surface hardness attained was not affected by pre-stress during hardening, and ranged from 513 to 676 kg/mm2. The depth of effective hardening varied at different magnitudes of pre-stress, but did not vary proportionately to the pre-stress. The surface residual stress, coinciding with the maximum compressive residual stress, increased as pre-stress was increased, from 1040 MPa for the nominally treated specimens to 1270 MPa for specimens pre-stressed to 230 MPa. The maximum tensile residual stress observed in the specimens decreased from 1060 MPa in the nominally treated specimens to 760 MPa for specimens pre-stressed to 230 MPa. Similarly, thickness of the compressive residual stress region increased and the depth at which maximum tensile residual stress occurred increased as the pre-stress during treatment was increased Overall, application of tensile elastic pre-stress during LASER hardening is beneficial to the development of compressive residual stress in AISI 4140, with minimal impact to the hardness attained from the treatment. The newly developed approach for LASER hardening may support efforts to increase both the wear and fatigue resistance of parts made from hardenable steels.

  4. Hardness of oxynitride glasses: topological origin.

    PubMed

    Paraschiv, Georgiana L; Gomez, Sinue; Mauro, John C; Wondraczek, Lothar; Yue, Yuanzheng; Smedskjaer, Morten M

    2015-03-12

    Oxynitride glasses are mixed-anion systems, in which the 2-fold coordinated oxygen atoms have been partially substituted by 3-fold coordinated nitrogen atoms. This so-called nitridation process introduces additional bonds and thereby constrains and compacts the glass network and consequently alters the glass hardness. To explore how and why hardness varies with the degree of nitridation, we have derived a topological model of oxynitride glass hardness using temperature-dependent constraint theory, by which the scaling of glass hardness with nitrogen content can be predicted. A linear model has been derived based on the assumption that the substitution of oxygen atoms with nitrogen atoms is responsible for the hardness increase due to the increase in the number (n) of bond-bending and bond-angular constraints. It turns out that the model agrees with the experimental observation, i.e., an approximate positive linear trend of the hardness change with nitrogen content is observed for a wide range of glass compositions. The topological model may thus be useful for designing new oxynitride glass compositions with targeted hardness values. PMID:25692458

  5. Novel hard compositions and methods of preparation

    DOEpatents

    Sheinberg, H.

    1981-02-03

    Novel very hard compositions of matter are prepared by using in all embodiments only a minor amount of a particular carbide (or materials which can form the carbide in situ when subjected to heat and pressure); and no strategic cobalt is needed. Under a particular range of conditions, densified compositions of matter of the invention are prepared having hardnesses on the Rockwell A test substantially equal to the hardness of pure tungsten carbide and to two of the hardest commercial cobalt-bonded tungsten carbides. Alternately, other compositions of the invention which have slightly lower hardnesses than those described above in one embodiment also possess the advantage of requiring no tungsten and in another embodiment possess the advantage of having a good fracture toughness value.

  6. Organizing Your Hard Disk.

    ERIC Educational Resources Information Center

    Stocker, H. Robert; Hilton, Thomas S. E.

    1991-01-01

    Suggests strategies that make hard disk organization easy and efficient, such as making, changing, and removing directories; grouping files by subject; naming files effectively; backing up efficiently; and using PATH. (JOW)

  7. Counting coins and value

    NSDL National Science Digital Library

    Mrs. Christian

    2007-03-21

    Students will identify and add up coins. Please complete the games in order. You must finish each game before going on to the next one. Game #1: Counting Money - Values of coins Game #2:Counting Money (harder) Game #3: Let s Compare (hardest) Game #4: Money Hard Game #5: Cash Out--Very Difficult Math Game ...

  8. Benchmarking for maximum value.

    PubMed

    Baldwin, Ed

    2009-03-01

    Speaking at the most recent Healthcare Estates conference, Ed Baldwin, of international built asset consultancy EC Harris LLP, examined the role of benchmarking and market-testing--two of the key methods used to evaluate the quality and cost-effectiveness of hard and soft FM services provided under PFI healthcare schemes to ensure they are offering maximum value for money. PMID:19344004

  9. Implementing QML for radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; M. D. Terry; M. R. Shaneyfelt

    1990-01-01

    The US government has proposed a qualified manufacturers list (QML) methodology to qualify integrated circuits for high reliability and radiation hardness. An approach to implementing QML for single-event upset (SEU) immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates is demonstrated. It is seen that the process capability indices, Cp and Cpk, for the

  10. Implementing QML for radiation hardness assurance

    Microsoft Academic Search

    P. S. Winokur; F. W. Sexton; D. M. Fleetwood; M. D. Terry; M. R. Shaneyfelt; P. V. Dressendorfer; J. R. Schwank

    1990-01-01

    The US government has proposed a qualified manufacturers list (QML) methodology to qualify integrated circuits for high reliability and radiation hardness. An approach to implementing QML for single-event upset (SEU) immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates is demonstrated. It is seen that the process capability indices, Cp and C pk, for

  11. Electronegativities and hardnesses of open shell atoms

    Microsoft Academic Search

    José L. Gázquez; Elba Ortiz

    1984-01-01

    A Taylor series expansion of the energy of an atomic system around the neutral atom value, which introduces the first and second derivatives of the energy with respect to the number of electrons (electronegativity ?, and hardness &eegr;, respectively) is proposed. The relaxed first derivative and the unrelaxed second derivative of the X? and hyper-Hartree–Fock methods are used to relate

  12. Implementing QML for radiation hardness assurance

    SciTech Connect

    Winokur, P.S.; Sexton, F.W.; Fleetwood, D.M.; Terry, M.D.; Shaneyfelt, M.R.; Dressendorfer, P.V.; Schwank, J.R. (Sandia National Labs., Albuquerque, NM (USA))

    1990-12-01

    Statistical process control (SPC) of technology parameters relevant to radiation hardness, test structure to IC correlation, and extrapolation from laboratory to threat scenarios are keys to implementing QML for radiation hardness assurance {ital in a cost-effective manner}. Data from approximately 300 wafer lots fabricated in a 4/3-{mu}m and CMOS IIIA (2-{mu}m) technologies are used to demonstrate approaches to, and highlight issues associated with, implementing QML for radiation-hardened CMOS in space applications. An approach is demonstrated to implement QML for single-event upset (SEU) immunity on 16 k SRAMs that involves relating values of feedback resistance to system error rates.

  13. Work Hard. Be Nice

    ERIC Educational Resources Information Center

    Mathews, Jay

    2009-01-01

    In 1994, fresh from a two-year stint with Teach for America, Mike Feinberg and Dave Levin inaugurated the Knowledge Is Power Program (KIPP) in Houston with an enrollment of 49 5th graders. By this Fall, 75 KIPP schools will be up and running, setting children from poor and minority families on a path to college through a combination of hard work,…

  14. Soft Skills, Hard Science

    E-print Network

    Wu, Mingshen

    Soft Skills, Hard Science: A Program to Improve Job Placement of STEM Graduates with Disabilities 2013 Women & Science Conference1 Wednesday, May 22, 13 #12;Why focus on soft skills? What comes to mind rated recent grads on same skills Perception Reality 8 Wednesday, May 22, 13 #12;what are soft skills

  15. Hard (and Soft) Facts.

    ERIC Educational Resources Information Center

    Kennedy, Mike

    1999-01-01

    Provides guidelines to help schools maintain hard floors and carpets, including special areas in schools and colleges that need attention and the elements needed to have a successful carpet-maintenance program. The importance of using heavy equipment to lessen time and effort is explained as are the steps maintenance workers can take to make the…

  16. Color stability and hardness in dental composites after accelerated aging

    Microsoft Academic Search

    Karen A Schulze; Sally J Marshall; Stuart A Gansky; Grayson W Marshall

    2003-01-01

    Objectives. To investigate the color and microhardness changes of five chemically- and five light-curing composites as a function of accelerated aging from light exposure.Materials and methods. From each material five composite specimens were embedded in epoxy resin prior to determining the Knoop microhardness of the surface. For analyzing the color ?E?=f((L?a?b?)) with a spectrophotometer, three discs per composite were prepared.

  17. Effects of hard particles on friction coefficients and particle embedment in brake system during hard braking

    NASA Astrophysics Data System (ADS)

    Abdul Hamid, M. K.; Stachowiak, G. W.; Syahrullail, S.

    2012-06-01

    The effects of hard particles on the friction coefficients and particle embedment during hard braking were investigated. Silica sands grit of the size between 180 to 355 ?m were used during the experiments. The results were compared to the results obtained without the grit particles present in order to determine the change in friction coefficient, the fluctuation of frictional oscillation amplitude, and the percentage of particle embedment. Different sliding speeds were applied to investigate the relationship between particle embedment with friction coefficient and friction oscillation amplitude. Presence of hard particles of different grit size is found to significantly affect the friction coefficient and standard deviation of friction oscillation amplitude values. The friction coefficient and standard deviation values of friction oscillation amplitude increase with particle embedment due to the rapid changes of the effective contact area and the abrasion mode operating in the gap interface. Also, particle embedment tends to increase the disc surface roughness and influence the stopping time of the disc.

  18. Local hardness equalization and the principle of maximum hardness.

    PubMed

    Gázquez, José L; Vela, Alberto; Chattaraj, Pratim K

    2013-06-01

    The chemical potential, hardness, and hyperhardnesses equalization principles are used to show that the leading term associated with charge transfer in the total interaction energy among the fragments in which a molecule is divided is directly proportional to minus the hardness of the molecule in its ground state, as established by the principle of maximum hardness. The additional terms in the interaction energy, associated with the changes in the external potential of the fragments, provide explanation for deviations between the point of maximum hardness and the point of minimum energy. It is also found that the dual descriptor plays a very important role in hardness equalization. PMID:23758354

  19. Hardness measurement of CVD diamond coatings on SiC substrates

    Microsoft Academic Search

    S. Chowdhury; E. de Barra; M. T. Laugier

    2005-01-01

    Hardness of CVD diamond coatings was determined by CSM™ nanohardness tester (NHT) and Vickers microhardness tester. Nanoindentation measurements were performed with loads from 50 to 300 mN and measured hardness and elastic modulus values were about 105 and 1147 GPa, respectively. These values were compared with the values found from the Vickers microhardness tester. This work justifies the use of

  20. Hard metal composition

    DOEpatents

    Sheinberg, Haskell (Los Alamos, NM)

    1986-01-01

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 weight percent boron carbide and the remainder a metal mixture comprising from 70 to 90 percent tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 to 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  1. Hardness of Materials- Introduction

    NSDL National Science Digital Library

    This lesson plan from Edmonds Community College will serve as an excellent introduction to the hardness of materials. The module illustrates the differences in properties between different materials. Students will determine property differences between different types of materials, observe property differences between materials of the same class, measure, record and report their results and observe differences in results due to operator error. Student, instructor and course evaluation questions are included. This document will serve as a framework for instructors and may be downloaded in PDF format.

  2. Hard metal composition

    DOEpatents

    Sheinberg, H.

    1983-07-26

    A composition of matter having a Rockwell A hardness of at least 85 is formed from a precursor mixture comprising between 3 and 10 wt % boron carbide and the remainder a metal mixture comprising from 70 to 90% tungsten or molybdenum, with the remainder of the metal mixture comprising nickel and iron or a mixture thereof. The composition has a relatively low density of between 7 and 14 g/cc. The precursor is preferably hot pressed to yield a composition having greater than 100% of theoretical density.

  3. Evaluation of mechanical properties of some glycine complexes

    SciTech Connect

    Nagaraju, D. [Department of Physics, PG Centre, Lal Bahadur College, Warangal - 506007 (India); Raja Shekar, P. V., E-mail: pvrsleo@gmail.com [Department of Physics, SR Engineering College, Warangal - 506371 (India); Chandra, Ch. Sateesh [Department of Physics, Kakatiya Institute of Technology and Sciences, Warangal - 506015 (India); Rao, K. Kishan; Krishna, N. Gopi [Department of Physics, Kakatiya University, Warangal - 506009 (India)

    2014-04-24

    The variation of Vickers hardness with load for (101) glycine zinc chloride (GZC), (001) glycine lithium sulphate (GLS), (001) triglycine sulphate (TGS) and (010) glycine phosphite (GPI) crystals was studied. From the cracks initiated along the corners of the indentation impression, crack lengths were measured and the fracture toughness value and brittle index number were determined. The hardness related parameters viz. yield strength and Young’s modulus were also estimated. The anisotropic nature of the crystals was studied using Knoop indentation technique.

  4. Valued Constraint Satisfaction Problems: Hard and Easy Problems

    Microsoft Academic Search

    Thomas Schiex; Hélène Fargier; Gérard Verfaillie

    1995-01-01

    In order to deal with over-constrained Constraint Satisfaction Problems, various extensions of the CSP framework have been considered by taking into account costs, uncertainties, preferences, pri­ orities...Each extension uses a specific mathemat­ ical operator (+, max...) to aggregate constraint violations. In this paper, we consider a simple algebraic frame­ work, related to Partial Constraint Satisfaction, which subsumes most of these

  5. Hard Metal Disease

    PubMed Central

    Bech, A. O.; Kipling, M. D.; Heather, J. C.

    1962-01-01

    In Great Britain there have been no published reports of respiratory disease occurring amongst workers in the hard metal (tungsten carbide) industry. In this paper the clinical and radiological findings in six cases and the pathological findings in one are described. In two cases physiological studies indicated mild alveolar diffusion defects. Histological examination in a fatal case revealed diffuse pulmonary interstitial fibrosis with marked peribronchial and perivascular fibrosis and bronchial epithelial hyperplasia and metaplasia. Radiological surveys revealed the sporadic occurrence and low incidence of the disease. The alterations in respiratory mechanics which occurred in two workers following a day's exposure to dust are described. Airborne dust concentrations are given. The industrial process is outlined and the literature is reviewed. The toxicity of the metals is discussed, and our findings are compared with those reported from Europe and the United States. We are of the opinion that the changes which we would describe as hard metal disease are caused by the inhalation of dust at work and that the component responsible may be cobalt. Images PMID:13970036

  6. Expected Value

    NSDL National Science Digital Library

    Siegrist, Kyle

    This online, interactive lesson on expected value provides examples, exercises, and applets in which students will explore relationships between the expected value of real-valued random variables and the center of the distribution. Students will also examine how expected values can be used to measure spread and correlation.

  7. Connectivity percolation in suspensions of hard platelets

    E-print Network

    Maneesh Mathew; Tanja Schilling; Martin Oettel

    2012-04-13

    We present a study on connectivity percolation in suspensions of hard platelets by means of Monte Carlo simulation. We interpret our results using a contact-volume argument based on an effective single--particle cell model. It is commonly assumed that the percolation threshold of anisotropic objects scales as their inverse aspect ratio. While this rule has been shown to hold for rod-like particles, we find that for hard plate-like particles the percolation threshold is non-monotonic in the aspect ratio. It exhibits a shallow minimum at intermediate aspect ratios and then saturates to a constant value. This effect is caused by the isotropic-nematic transition pre-empting the percolation transition. Hence the common strategy to use highly anisotropic, conductive particles as fillers in composite materials in order to produce conduction at low filler concentration is expected to fail for plate-like fillers such as graphene and graphite nanoplatelets.

  8. Concept Mapping: Soft Science or Hard Art?

    NSDL National Science Digital Library

    William Trochim

    In this paper the scientific side of concept mapping is viewed as "soft science" and the artistic one as "hard art" to imply that the process has some qualities of both, but probably does not fall exclusively within either's domain. In the spirit of hard art, a "gallery" of final concept maps from twenty projects is presented, partly to illustrate more examples of the process when used in a variety of subject areas and for different purposes, and partly for their aesthetic value alone. In the spirit of soft science, two major issues are considered. First, the evidence for the validity and reliability of concept mapping is introduced, along with some suggestions for further research which might be undertaken to examine those characteristics. Second, the role of concept mapping is discussed, with special emphasis on its use in a pattern matching framework. This document is intended for use by novice evaluators and professional evaluators in workshops and conferences.

  9. Maximum Chemical and Physical Hardness

    Microsoft Academic Search

    Ralph G. Pearson

    1999-01-01

    Density functional theory (DFT) is briefly reviewed, especially concepts such as the electronic chemical potential and the hardness of the electron density function. There is much evidence, and a mathematical proof, that this chemical hardness is a maximum for an equilibrium system. The proof is based on a combination of statistical mechanics, the fluctuation-dissipation theorem, and correlation functions. In MO

  10. Measuring the Hardness of Minerals

    ERIC Educational Resources Information Center

    Bushby, Jessica

    2005-01-01

    The author discusses Moh's hardness scale, a comparative scale for minerals, whereby the softest mineral (talc) is placed at 1 and the hardest mineral (diamond) is placed at 10, with all other minerals ordered in between, according to their hardness. Development history of the scale is outlined, as well as a description of how the scale is used…

  11. Subjective hardness of compliant materials

    Microsoft Academic Search

    Roland Harper; S. S. Stevens

    1964-01-01

    The apparent hardness and softness of nine samples of compliant materials were scaled by direct magnitude estimation and by cross-modal matches to the apparent force exerted on a hand dynamometer and a finger dynamometer, and to the loudness of a band of white noise. The physical hardness (force\\/indentation) of the compliant specimens covered a range of more than 100 to

  12. Cyclic strength of hard metals

    SciTech Connect

    Sereda, N.N.; Gerikhanov, A.K.; Koval'chenko, M.S.; Pedanov, L.G.; Tsyban', V.A.

    1986-02-01

    The authors study the strength of hard-metal specimens and structural elements under conditions of cyclic loading since many elements of processing plants, equipment, and machines are made of hard metals. Fatigue tests were conducted on KTS-1N, KTSL-1, and KTNKh-70 materials, which are titanium carbide hard metals cemented with nickel-molybdenum, nickelcobalt-chromium, and nickel-chromium alloys, respectively. As a basis of comparison, the standard VK-15 (WC+15% Co) alloy was used. Some key physicomechanical characteristics of the materials investigated are presented. On time bases not exceeding 10/sup 6/ cycles, titanium carbide hard metals are comparable in fatigue resistance to the standard tungstencontaining hard metals.

  13. Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements.

    PubMed

    Calgaro, Patricia Angélica Milani; Furuse, Adilson Yoshio; Correr, Gisele Maria; Ornaghi, Bárbara Pick; Gonzaga, Carla Castiglia

    2013-01-01

    This study evaluated: I) the effect of photo-activation through ceramics on the degree of conversion (DC) and on the Knoop hardness (KHN) of light- and dual-cured resin cements; and II) two different protocols for obtaining the spectra of uncured materials, to determine the DC of a dual-cured resin cement. Thin films of cements were photo-activated through ceramics [feldspathic porcelain (FP); lithium disilicate glass-ceramics of low translucency (e.max-LT), medium opacity (e.max-MO) and high translucency (e.max-HT); glass-infiltrated alumina composite (IC) and polycrystalline zirconia (ZR)] with thicknesses of 1.5 and 2.0 mm. DC was analyzed by Fourier transform infrared (FTIR) spectroscopy. Two protocols were used to obtain the spectra of the uncured materials: I) base and catalyst pastes were mixed, and II) thin films of base and catalyst pastes were obtained separately, and an average was obtained. KHN assessment was performed with cylindrical specimens. The results were analyzed by ANOVA and Tukey's test (?= 0.05). The light-cured cement showed higher DC (61.9%) than the dual-cured cement (55.7%). The DC varied as follows: FP (65.4%), e.max-HT (65.1%), e.max-LT (61.8%), e.max-MO (60.9%), ZR (54.8%), and IC (44.9%). The light-cured cement showed lower KHN (22.0) than the dual-cured (25.6) cement. The cements cured under 1.5 mm spacers showed higher KHN (26.2) than when polymerized under 2.0 mm ceramics (21.3). Regarding the two protocols, there were significant differences only in three groups. Thus, both methods can be considered appropriate. The physical and mechanical properties of resin cements may be affected by the thickness and microstructure of the ceramic material interposed during photo-activation. PMID:24036978

  14. Exchange-spring mechanism of soft and hard ferrite nanocomposites

    SciTech Connect

    Manjura Hoque, S., E-mail: manjura_hoque@yahoo.com [Materials Science Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission (Bangladesh); Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Srivastava, C.; Kumar, V.; Venkatesh, N. [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Das, H.N.; Saha, D.K. [Materials Science Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission (Bangladesh); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore (India)

    2013-08-01

    Graphical abstract: - Highlights: • Exchange-spring behaviour of soft and hard ferrites was studied. • XRD patterns indicated soft and hard ferrites as fcc and hcp structure. • Hysteresis loops indicate wide difference in coercivity of soft and hard phases. • Nanocomposites produced convex hysteresis loop characteristic of single-phase. - Abstract: The paper reports exchange-spring soft and hard ferrite nanocomposites synthesized by chemical co-precipitation with or without the application of ultrasonic vibration. The composites contained BaFe{sub 12}O{sub 19} as the hard phase and CoFe{sub 2}O{sub 4}/MgFe{sub 2}O{sub 4} as the soft phase. X-ray diffraction patterns of the samples in the optimum calcined condition indicated the presence of soft ferrites as face-centred cubic (fcc) and hard ferrites as hexagonal close packed (hcp) structure respectively. Temperature dependence of magnetization in the range of 20–700 °C demonstrated distinct presence of soft and hard ferrites as magnetic phases which are characterized by wide difference in magnetic anisotropy and coercivity. Exchange-spring mechanism led these nanocomposite systems to exchange-coupled, which ultimately produced convex hysteresis loops characteristic of a single-phase permanent magnet. Fairly high value of coercivity and maximum energy product were observed for the samples in the optimum calcined conditions with a maximum applied field of 1600 kA/m (2 T)

  15. Hardness potential derivatives and their relation to Fukui indices.

    PubMed

    Saha, Soumen; Bhattacharjee, Rituparna; Roy, Ram Kinkar

    2013-03-30

    A simple as well as easy to compute formalism of hardness potential (originally defined by Parr and Gazquez, J. Phys. Chem., 1993, 97, 3939) is presented. Use of hardness potential formally resolves the N-dependence problem of local hardness. However, the hardness potential cannot describe the intra as well as intermolecular reactivity sequence satisfactorily of some chemical systems. The corresponding electrophilic [?(+)h(k)] and nucleophilic [?(-)h(k)] variants of the hardness potential are also developed, which measure the reactivity toward a nucleophilic (i.e., Nu(-)) and an electrophilic (i.e., El(+)) reagent, respectively. Interestingly, these two variants of the hardness potential lead to the right and left derivatives of Fukui potential. The proposed reactivity descriptors correctly predict the expected reactivity trends in the chosen systems. It has also been illustrated that the values of the variants of hardness potential (or Fukui potential) at the atomic nucleus have the ability to explain the intramolecular reactivity of biologically active indole derivatives. The future scope of applications as well as limitations of the proposed descriptors is also highlighted. PMID:23175426

  16. PROTEINS, HARDNESS AND ALLERGENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteins are key constituents of wheat grain and flour. A number of specific proteins/classes of proteins are critical to the processing and end-use quality, and hence value and utility of wheat. The commercially important proteins of wheat may be broadly classified as glutenins and gliadins of va...

  17. Correlation of Yield Strength and Tensile Strength with Hardness for Steels

    NASA Astrophysics Data System (ADS)

    Pavlina, E. J.; van Tyne, C. J.

    2008-12-01

    Hardness values as well as yield and tensile strength values were compiled for over 150 nonaustenitic, hypoeutectoid steels having a wide range of compositions and a variety of microstructures. The microstructures include ferrite, pearlite, martensite, bainite, and complex multiphase structures. The yield strength of the steels ranged from approximately 300 MPa to over 1700 MPa. Tensile strength varied over the range of 450-2350 MPa. Regression analysis was used to determine the correlation of the yield strength and the tensile strength to the diamond pyramid hardness values for these steels. Both the yield strength and tensile strength of the steels exhibited a linear correlation with the hardness over the entire range of strength values. Empirical relationships are provided that enable the estimation of strength from a bulk hardness measurement. A weak effect of strain-hardening potential on the hardness-yield strength relationship was also observed.

  18. Easy Problems are Sometimes Hard

    Microsoft Academic Search

    Ian P. Gent; Toby Walsh

    1994-01-01

    We present a detailed experimental investigation of the easy-hard-easyphase transition for randomly generated instances of satisfiability problems.Problems in the hard part of the phase transition have been extensively usedfor benchmarking satisfiability algorithms. This study demonstrates thatproblem classes and regions of the phase transition previously thought tobe easy can sometimes be orders of magnitude more difficult than the worstproblems in problem

  19. Sintered titanium carbide hard alloys

    Microsoft Academic Search

    G. V. Samsonov; N. N. Sergeev; G. T. Dzodziev; V. K. Vitryanyuk; L. V. Latyaeva

    1971-01-01

    1.A study was made of the preparation of titanium carbide hard alloys with a nickel binder. It is shown that satisfactory mechanical properties (bend strength 107–115 kg\\/mm2, hardness 90–90.5 HRA) are exhibited by 80% TiC-20% Ni alloys produced from fine-milled mixtures by sintering in a vacuum of 5·10-3 mm Hg at a temperature of 1300‡C and an isothermal holding time

  20. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…

  1. Place Values

    NSDL National Science Digital Library

    AAA Math

    2007-12-12

    This site has explanatory lessons, interactive practice, and challenge games all dealing with place value. Includes information, practice, and games on place value of two, three, six and seven digit numbers and expandend notation for two, three, six, and seven digit numbers. Problems are randomly selected and students receive immediate feedback with the correct response. The bottom of each lesson page contains timed exercises.

  2. Hard-on-Hard Total Hip Impingement Causes Extreme Contact Stress Concentrations

    PubMed Central

    Elkins, Jacob M.; O’Brien, Megan K.; Stroud, Nicholas J.; Pedersen, Douglas R.; Callaghan, John J.

    2010-01-01

    Background Impingement events, in addition to their role immediately proximate to frank dislocation, hold the potential to damage new-generation hard-on-hard bearings as a result of the relatively unforgiving nature of the materials and designs. Because of the higher stiffness and tighter design tolerances of metal-on-metal and ceramic implants, surgical positioning plausibly has become even more important. Questions/purposes We asked (1) whether, and under what cup orientation conditions, hard-on-hard impingements might challenge implant material failure strength; and (2) whether particle generation propensity at impingement and egress sites would show similar dependence on cup orientation. Methods Realistic computational simulations were enabled by multistage finite element analyses, addressing both global construct motion and loading, and focal stress concentrations at neck impingement and rim egress sites. The global model, validated by a cadaveric simulation in a servohydraulic hip simulator, included both hardware components and advanced anisotropic capsule characterization. Parametric computational runs explored the effect of cup orientation for both ceramic-on-ceramic and metal-on-metal bearing couples for two distinct motion sequences associated with dislocation. Results Stress concentrations from impingement increased nearly linearly with increased cup tilt and with cup anteversion. In some situations, peak values of stress approached or exceeded 1 GPa, levels challenging the yield strength of cobalt-chromium implants, and potentially the fracture strength of ceramics. The tendency for impingement events to generate debris, indexed in terms of a new scraping severity metric, showed orientation dependences similar to that for bulk material failure. Conclusions Damage propensity arising from impingement events in hard total hip bearings is highly orientation-dependent. PMID:20953853

  3. Solar cell nanotechnology for improved efficiency and radiation hardness

    Microsoft Academic Search

    Alexander I. Fedoseyev; Marek Turowski; Qinghui Shao; Alexander A. Balandin

    2006-01-01

    Space electronic equipment, and NASA future exploration missions in particular, require improvements in solar cell efficiency and radiation hardness. Novel nano-engineered materials and quantum-dot array based photovoltaic devices promise to deliver more efficient, lightweight solar cells and arrays which will be of high value to long term space missions. In this paper, we describe issues related to the development of

  4. WCET analysis of probabilistic hard real-time systems

    Microsoft Academic Search

    Guillem Bernat; Antoine Colin; Stefan M. Petters

    2002-01-01

    Traditional approaches for worst case execution time (WCET) analysis produce values which are very pessimistic if applied to modern processors. In addition, end to end measurements as used in industry produce estimates of the execution time that potentially underestimate the real worst case execution time. We introduce the notion of probabilistic hard real-time systems which have to meet all the

  5. Depletion effects in smectic phases of hard-rod-hard-sphere mixtures

    NASA Astrophysics Data System (ADS)

    Mart?nez-Ratón, Y.; Cinacchi, G.; Velasco, E.; Mederos, L.

    2006-10-01

    It is known that when hard spheres are added to a pure system of hard rods the stability of the smectic phase may be greatly enhanced, and that this effect can be rationalised in terms of depletion forces. In the present paper we first study the effect of orientational order on depletion forces in this particular binary system, comparing our results with those obtained adopting the usual approximation of considering the rods parallel and their orientations frozen. We consider mixtures with rods of different aspect ratios and spheres of different diameters, and we treat them within Onsager theory. Our results indicate that depletion effects, and consequently smectic stability, decrease significantly as a result of orientational disorder in the smectic phase when compared with corresponding data based on the frozen-orientation approximation. These results are discussed in terms of the ? parameter, which has been proposed as a convenient measure of depletion strength. We present closed expressions for ?, and show that it is intimately connected with the depletion potential. We then analyse the effect of particle geometry by comparing results pertaining to systems of parallel rods of different shapes (spherocylinders, cylinders and parallelepipeds). We finally provide results based on the Zwanzig approximation of a fundamental-measure density-functional theory applied to mixtures of parallelepipeds and cubes of different sizes. In this case, we show that the ? parameter exhibits a linear asymptotic behaviour in the limit of large values of the hard-rod aspect ratio, in conformity with Onsager theory, as well as in the limit of large values of the ratio of rod breadth to cube side length, d, in contrast to Onsager approximation, which predicts ? ˜ d3. Based on both this result and the Percus-Yevick approximation for the direct correlation function for a hard-sphere binary mixture in the same limit of infinite asymmetry, we speculate that, for spherocylinders and spheres, the ? parameter should be of order unity as d tends to infinity.

  6. Effects of threshold of hard cut based technique for advertisement detection in TV video streams

    Microsoft Academic Search

    Ashish Tanwer; Parminder Singh Reel

    2010-01-01

    Advertisement detection in a TV video recording\\/archiving system is a challenging task. In this paper, shot change (hard cut) detection that is based on ¿inter-frame difference¿, ¿normalized difference energy¿ and the ¿normalized sum of absolute differences¿ and its comparison with a threshold are discussed. The effects of changing video threshold on hard cut detection have been summarized. A threshold value

  7. Simulation and approximate formulae for the radial distribution functions of highly asymmetric hard sphere mixtures

    Microsoft Academic Search

    Douglas Henderson; Andrij Trokhymchuk; Leslie V. Woodcock; Kwong-Yu Chan

    2005-01-01

    The Henderson and Chan (HC) formulae for the contact values of the radial distribution functions (RDFs) of a highly asymmetric hard sphere mixture are reconsidered in light of a recent formula of Roth, Evans and Dietrich for the RDF of a pair of exceedingly large spheres at zero concentration in a solvent of small hard spheres. Two modifications of the

  8. Comparison of time-dependent changes in the surface hardness of different composite resins

    PubMed Central

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P < 0.05). The lowest was obtained with Filtek Silorane. The hardness values of all test groups increased after 24 h (P < 0.05). Conclusion: Although silorane-based composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

  9. Universal Hard-Loop Actions

    E-print Network

    Czajka, Alina

    2015-01-01

    The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs irrespective of a field content of each theory and of variety of specific interactions. Consequently, the long-wavelength or semiclassical features of plasma systems governed by these theories such as collective excitations are almost identical. An origin of the universality, which holds within the limits of applicability of the hard-loop approach, is discussed.

  10. Universal Hard-Loop Actions

    E-print Network

    Alina Czajka; Stanislaw Mrowczynski

    2015-05-29

    The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs irrespective of a field content of each theory and of variety of specific interactions. Consequently, the long-wavelength or semiclassical features of plasma systems governed by these theories such as collective excitations are almost identical. An origin of the universality, which holds within the limits of applicability of the hard-loop approach, is discussed.

  11. Crop Values

    NSDL National Science Digital Library

    While economic data on crop values are strictly commercial/ agricultural summaries, they can be useful as surrogate indices of land use/ cover change, or in estimating food subsidies (e.g. waste grain) for wildlife. Posted by the US Department of Agriculture (USDA) Economics and Statistics System at Cornell University, the site contains the "annual marketing year average prices and value of production of principal crops". Principal crops include barley (all, feed, and malting), hay, oats, rye, wheat (all, winter, durum, and other spring), upland and American-pima cotton and cottonseed, corn, dry beans, flaxseed, peanuts, sorghum, soybeans, sunflowers, and rice. These data are provided by the National Agricultural Statistics Service (USDA).

  12. Collision statistics in sheared inelastic hard spheres.

    PubMed

    Bannerman, Marcus N; Green, Thomas E; Grassia, Paul; Lue, Leo

    2009-04-01

    The dynamics of sheared inelastic-hard-sphere systems is studied using nonequilibrium molecular-dynamics simulations and direct simulation Monte Carlo. In the molecular-dynamics simulations Lees-Edwards boundary conditions are used to impose the shear. The dimensions of the simulation box are chosen to ensure that the systems are homogeneous and that the shear is applied uniformly. Various system properties are monitored, including the one-particle velocity distribution, granular temperature, stress tensor, collision rates, and time between collisions. The one-particle velocity distribution is found to agree reasonably well with an anisotropic Gaussian distribution, with only a slight overpopulation of the high-velocity tails. The velocity distribution is strongly anisotropic, especially at lower densities and lower values of the coefficient of restitution, with the largest variance in the direction of shear. The density dependence of the compressibility factor of the sheared inelastic-hard-sphere system is quite similar to that of elastic-hard-sphere fluids. As the systems become more inelastic, the glancing collisions begin to dominate over more direct, head-on collisions. Examination of the distribution of the times between collisions indicates that the collisions experienced by the particles are strongly correlated in the highly inelastic systems. A comparison of the simulation data is made with direct Monte Carlo simulation of the Enskog equation. Results of the kinetic model of Montanero [J. Fluid Mech. 389, 391 (1999)] based on the Enskog equation are also included. In general, good agreement is found for high-density, weakly inelastic systems. PMID:19518225

  13. Adding Value.

    ERIC Educational Resources Information Center

    Orsini, Larry L.; Hudack, Lawrence R.; Zekan, Donald L.

    1999-01-01

    The value-added statement (VAS), relatively unknown in the United States, is used in financial reports by many European companies. Saint Bonaventure University (New York) has adapted a VAS to make it appropriate for not-for-profit universities by identifying stakeholder groups (students, faculty, administrators/support personnel, creditors, the…

  14. Valuing Difference?

    ERIC Educational Resources Information Center

    Watters, Kate

    2005-01-01

    How well are adult and community learning providers doing when it comes to ensuring equality of opportunity (EO) and valuing diversity? Many are in transition from a defensive position of emphasising legal compliance towards making respect for diversity intrinsic to their strategic aims, plans and actions, according to the February edition of…

  15. Covering Problems with Hard Capacities

    Microsoft Academic Search

    Julia Chuzhoy; Joseph Naor

    2002-01-01

    We consider the classical vertex cover and set cover problems with the addition of hard capacity constraints. This means that a set (vertex) can only cover a limited number of its elements (adjacent edges) and the number of available copies of each set (vertex) is bounded. This is a natural generalization of the classical problems that also captures resource limitations

  16. Hard scattering in gammap interactions

    Microsoft Academic Search

    T. Ahmed; V. Andreev; B. Andrieu; M. Arpagaus; A. Babayev; H. Bärwolff; J. Ban; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; G. A. Beck; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; U. Berthon; G. Bertrand-Coremans; M. Besancon; P. Biddulph; E. Binder; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; C. Coutures; G. Cozzika; L. Criegee; J. Cvach; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. Delbuono; M. Devel; A. Deroeck; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; Y. Feng; I. F. Fensome; J. Ference; F. Ferrarotto; W. Flauger; M. Fleischer; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formanek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; A. Gellrich; M. Gennis; U. Gensch; H. Genzel; R. Gerhards; D. Gillespie; L. Godfrey; U. Goerlach; L. Goerlich; M. Goldberg; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; D. Handschuh; E. M. Hanlon; M. Hapke; J. Harjes; P. Hartz; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; R. Hedgecock; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladky; K. C. Hoeger; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; M. A. Jabiol; A. Jacholkowska; C. Jacobson; M. Jaffre; L. Jönsson; K. Johannsen; D. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; S. Kasarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; H. Krehbiel; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; R. Lander; M. P. J. Landon; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; U. Lenhardt; A. Leuschner; C. Leverenz; D. Levin; S. Levonian; Ch. Ley; G. Lindström; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; V. Milone; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; J. M. Morton; K. Müller; P. Murin; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; D. Newton; H. K. Nguyen; F. Niebergall; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; U. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. P. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; R. Prosi; F. Raupach; K. Rauschnabel; P. Reimer; P. Ribarics; V. Riech; J. Riedlberger; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; E. Ryseck; J. Sacton; N. Sahlmann; E. Sanchez; D. P. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; V. Schröder; M. Schulz; A. Schwind; W. Scobel; U. Seehausen; R. Sell; M. Seman; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; L. Smolik; Y. Soloviev; H. Spitzer; P. Staroba; M. Steenbock; P. Steffen; R. Steinberg; H. Steiner; B. Stella; K. Stephens; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; G. Thompson; R. J. Thompson; I. Tichomirov; C. Trenkel; P. Truöl; V. Tchernyshov; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallee; P. Vanesch; A. Vartapetian; J. Vasdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegner; H. P. Wellisch; S. Willard; M. Winde; G.-G. Winter; M. Th. Wolff; L. A. Womersley; A. E. Wright; N. Wulff; T. P. Yiou; J. Zacek; P. Zavada; C. Zeitnitz; H. Ziaeepour; M. Zimmer; W. Zimmermann; F. Zomer

    1992-01-01

    We report on the investigation of the final state in interactions of quasi-real photons with protons. The data were taken with the H1 detector at the HERA ep collider. Evidence for hard interactions is seen in both single particle spectra and jet formation. The data can best be described by inclusion of resolved photon processess as predicted by QCD.

  17. FATIGUE OF BIOMATERIALS: HARD TISSUES

    PubMed Central

    Arola, D.; Bajaj, D.; Ivancik, J.; Majd, H.; Zhang, D.

    2009-01-01

    The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues of the human body, and includes bone, cementum, dentin and enamel. An understanding of their fatigue behavior and the influence of loading conditions and physiological factors (e.g. aging and disease) on the mechanisms of degradation are essential for achieving lifelong health. But there is much more to this topic than the immediate medical issues. There are many challenges to characterizing the fatigue behavior of hard tissues, much of which is attributed to size constraints and the complexity of their microstructure. The relative importance of the constituents on the type and distribution of defects, rate of coalescence, and their contributions to the initiation and growth of cracks, are formidable topics that have not reached maturity. Hard tissues also provide a medium for learning and a source of inspiration in the design of new microstructures for engineering materials. This article briefly reviews fatigue of hard tissues with shared emphasis on current understanding, the challenges and the unanswered questions. PMID:20563239

  18. Mixed Integer Linear Programming Method for Absolute Value Equations

    Microsoft Academic Search

    Longquan Yong

    2009-01-01

    We formulate the NP-hard absolute value equation as linear complementary problem when the singular values of A exceed one, and we proposed a mixed integer linear programming method to absolute value equation problem. The effectiveness of the method is demonstrated by its ability to solve random problems. Index Terms—absolute value equation; linear complementary problem; mixed integer linear programming. The basic

  19. Parameterized Complexity of k-Anonymity: Hardness and Tractability

    NASA Astrophysics Data System (ADS)

    Bonizzoni, Paola; Della Vedova, Gianluca; Dondi, Riccardo; Pirola, Yuri

    The problem of publishing personal data without giving up privacy is becoming increasingly important. A precise formalization that has been recently proposed is the k-anonymity, where the rows of a table are partitioned in clusters of size at least k and all rows in a cluster become the same tuple after the suppression of some entries. The natural optimization problem, where the goal is to minimize the number of suppressed entries, is hard even when the stored values are over a binary alphabet or the table consists of a bounded number of columns. In this paper we study how the complexity of the problem is influenced by different parameters. First we show that the problem is W[1]-hard when parameterized by the value of the solution (and k). Then we exhibit a fixed-parameter algorithm when the problem is parameterized by the number of columns and the number of different values in any column.

  20. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  1. Place Value

    NSDL National Science Digital Library

    Mrs. Egan

    2008-09-11

    These activities will help you learn more about place value. You will get to play some fun games to sharpen your skills! First, let\\'s practice writing the word names of some numbers, and then practice writing numbers that go with the word names. Click the link below to play the game. The first time you play, choose \\"Method 1: Spell numbers, 0-100\\". Record your score on your paper. Then ...

  2. Place Value

    NSDL National Science Digital Library

    Mrs. Lindley

    2005-10-24

    These activities will help you learn more about place value. You will get to play some fun games to sharpen your skills! First, let\\'s practice writing the word names of some numbers, and then practice writing numbers that go with the word names. Click the link below to play the game. The first time you play, choose \\"Method 1: Spell numbers, 0-100\\". Record your score on your paper. Then ...

  3. Hardness of FeB4: density functional theory investigation.

    PubMed

    Zhang, Miao; Lu, Mingchun; Du, Yonghui; Gao, Lili; Lu, Cheng; Liu, Hanyu

    2014-05-01

    A recent experimental study reported the successful synthesis of an orthorhombic FeB4 with a high hardness of 62(5) GPa [H. Gou et al., Phys. Rev. Lett. 111, 157002 (2013)], which has reignited extensive interests on whether transition-metal borides compounds will become superhard materials. However, it is contradicted with some theoretical studies suggesting transition-metal boron compounds are unlikely to become superhard materials. Here, we examined structural and electronic properties of FeB4 using density functional theory. The electronic calculations show the good metallicity and covalent Fe-B bonding. Meanwhile, we extensively investigated stress-strain relations of FeB4 under various tensile and shear loading directions. The calculated weakest tensile and shear stresses are 40 GPa and 25 GPa, respectively. Further simulations (e.g., electron localization function and bond length along the weakest loading direction) on FeB4 show the weak Fe-B bonding is responsible for this low hardness. Moreover, these results are consistent with the value of Vickers hardness (11.7-32.3 GPa) by employing different empirical hardness models and below the superhardness threshold of 40 GPa. Our current results suggest FeB4 is a hard material and unlikely to become superhard (>40 GPa). PMID:24811644

  4. Elasticity of Interfacial Rafts of Hard Particles with Soft Shells

    E-print Network

    Sebastian Knoche; Jan Kierfeld

    2015-05-10

    We study an elasticity model for compressed protein monolayers or particle rafts at a liquid interface. Based on the microscopic view of hard-core particles with soft shells, a bead-spring model is formulated and analyzed in terms of continuum elasticity theory. The theory can be applied, for example, to hydrophobin-coated air-water interfaces or, more generally, to liquid interfaces coated with an adsorbed monolayer of interacting hard-core particles. We derive constitutive relations for such particle rafts and describe the buckling of compressed planar liquid interfaces as well as their apparent Poisson ratio. We also use the constitutive relations to obtain shape equations for pendant or buoyant capsules attached to a capillary, and to compute deflated shapes of such capsules. A comparison with capsules obeying the usual Hookean elasticity (without hard cores) reveals that the hard cores trigger capsule wrinkling. Furthermore, it is shown that a shape analysis of deflated capsules with hard-core/soft-shell elasticity gives apparent elastic moduli which can be much higher than the original values if Hookean elasticity is assumed.

  5. Polarization observables in hard rescattering mechanism of deuteron photodisintegration

    NASA Astrophysics Data System (ADS)

    Sargsian, Misak M.

    2004-05-01

    Polarization properties of high energy photodisintegration of the deuteron are studied within the framework of the hard rescattering mechanism (HRM). In HRM, a quark of one nucleon knocked-out by the incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with high relative momentum. Summation of all relevant quark rescattering amplitudes allows us to express the scattering amplitude of the reaction through the convolution of a hard photon-quark interaction vertex, the large angle p-n scattering amplitude and the low momentum deuteron wave function. Within HRM, it is demonstrated that the polarization observables in hard photodisintegration of the deuteron can be expressed through the five helicity amplitudes of NN scattering at high momentum transfer. At 90° CM scattering HRM predicts the dominance of the isovector channel of hard pn rescattering, and it explains the observed smallness of induced, Py and transfered, Cx polarizations without invoking the argument of helicity conservation. Namely, HRM predicts that Py and Cx are proportional to the ?5 helicity amplitude which vanishes at ?cm=90° due to symmetry reasons. HRM predicts also a nonzero value for Cz in the helicity-conserving regime and a positive ? asymmetry which is related to the dominance of the isovector channel in the hard reinteraction. We extend our calculations to the region where large polarization effects are observed in pp scattering as well as give predictions for angular dependences.

  6. The Relationship Between Grain Hardness, Dough Mixing Parameters and Bread-Making Quality in Winter Wheat

    PubMed Central

    Salmanowicz, Boles?aw P.; Adamski, Tadeusz; Surma, Maria; Kaczmarek, Zygmunt; Karolina, Krystkowiak; Kuczy?ska, Anetta; Banaszak, Zofia; ?ugowska, Bogus?awa; Majcher, Ma?gorzata; Obuchowski, Wiktor

    2012-01-01

    The influence of grain hardness, determined by using molecular markers and physical methods (near-infrared (NIR) technique and particle size index—PSI) on dough characteristics, which in turn were determined with the use of a farinograph and reomixer, as well as bread-making properties were studied. The material covered 24 winter wheat genotypes differing in grain hardness. The field experiment was conducted at standard and increased levels of nitrogen fertilization. Results of molecular analyses were in agreement with those obtained by the use of physical methods for soft-grained lines. Some lines classified as hard (by physical methods) appeared to have the wild-type Pina and Pinb alleles, similar to soft lines. Differences in dough and bread-making properties between lines classified as hard and soft on the basis of molecular data appeared to be of less significance than the differences between lines classified as hard and soft on the basis of physical analyses of grain texture. Values of relative grain hardness at the increased nitrogen fertilization level were significantly higher. At both fertilization levels the NIR parameter determining grain hardness was significantly positively correlated with the wet gluten and sedimentation values, with most of the rheological parameters and bread yield. Values of this parameter correlated with quality characteristics in a higher degree than values of particle size index. PMID:22605973

  7. Why Are Drugs So Hard to Quit?

    MedlinePLUS Videos and Cool Tools

    Video: Why Are Drugs So Hard to Quit? Your browser does not support inline frames or is currently configured not to display inline ... link under the video: In English: Why Are Drugs So Hard to Quit? En español: ¿Por Qué ...

  8. Impact of aging on radiation hardness

    SciTech Connect

    Shaneyfelt, M.R.; Winokur, P.S.; Fleetwood, D.M. [and others

    1997-07-01

    Burn-in effects are used to demonstrate the potential impact of thermally activated aging effects on functional and parametric radiation hardness. These results have implications on hardness assurance testing. Techniques for characterizing aging effects are proposed.

  9. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, M.S.; Schuster, G.J.; Skorpik, J.R.

    1997-07-08

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part. 12 figs.

  10. Hard Photodisintegration of 3He

    NASA Astrophysics Data System (ADS)

    Granados, Carlos

    2011-02-01

    Large angle photodisintegration of two nucleons from the 3He nucleus is studied within the framework of the hard rescattering model (HRM). In the HRM the incoming photon is absorbed by one nucleon's valence quark that then undergoes a hard rescattering reaction with a valence quark from the second nucleon producing two nucleons emerging at large transverse momentum . Parameter free cross sections for pp and pn break up channels are calculated through the input of experimental cross sections on pp and pn elastic scattering. The calculated cross section for pp breakup and its predicted energy dependency are in good agreement with recent experimental data. Predictions on spectator momentum distributions and helicity transfer are also presented.

  11. Ultrasonic material hardness depth measurement

    DOEpatents

    Good, Morris S. (Richland, WA); Schuster, George J. (Kennewick, WA); Skorpik, James R. (Kennewick, WA)

    1997-01-01

    The invention is an ultrasonic surface hardness depth measurement apparatus and method permitting rapid determination of hardness depth of shafts, rods, tubes and other cylindrical parts. The apparatus of the invention has a part handler, sensor, ultrasonic electronics component, computer, computer instruction sets, and may include a display screen. The part handler has a vessel filled with a couplant, and a part rotator for rotating a cylindrical metal part with respect to the sensor. The part handler further has a surface follower upon which the sensor is mounted, thereby maintaining a constant distance between the sensor and the exterior surface of the cylindrical metal part. The sensor is mounted so that a front surface of the sensor is within the vessel with couplant between the front surface of the sensor and the part.

  12. Hard Determinism and the Moral "Ought"

    E-print Network

    Kuo, Lenore

    HARD DETERMINISM AND THE MORAL 'OUGHT' LENORE KUO The University of Nebraska at Omaha Philosophers from Aristotle to vanlnwagen 1 have questioned the possibility of preserving ethics if hard determinism is true. Thus it has been argued that we... must reject hard determinism because of the apparent "violence" it does to our basic conception of morality. For example, Howard Hintz maintains that: [Hard determinism) destroys the foundations of all prescriptive ethics except on the arbitrary...

  13. Artificially soft and hard surfaces in electromagnetics

    Microsoft Academic Search

    Per-Simon Kildal

    1990-01-01

    A transversely corrugated surface as used in corrugated horn antennas represents a soft boundary. A hard boundary is made by using longitudinal corrugations filled with dielectric material. The concept of soft and hard surfaces is treated in detail, considering different geometries. It is shown that both the hard and soft boundaries have the advantage of a polarization-independent reflection coefficient for

  14. PROTEIN COMPOSITION AND GRAIN HARDNESS IN SORGHUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain hardness is an important quality trait in sorghum. Grain hardness has been linked to milling and food quality as well as resistance to insects and mold. Despite the importance of grain hardness in sorghum, its biochemical basis is still not well understood. In sorghum, the grain is composed...

  15. Decreased ventilatory function in hard metal workers

    Microsoft Academic Search

    Y Kusaka; M Iki; S Kumagai; S Goto

    1996-01-01

    OBJECTIVES: To study individual effects on pulmonary function of exposure to hard metal including cobalt. METHODS: All of the workers in a hard metal company (583 men and 120 women) were examined for smoking, respiratory symptoms, ventilatory function, occupational history of exposure to hard metal, and present exposure to airborne cobalt. The ventilatory function indices (forced vital capacity (FVC), forced

  16. Surface Integrity Generated by Precision Hard Turning

    Microsoft Academic Search

    Y. Matsumoto; F. Hashimoto; G. Lahoti

    1999-01-01

    Rolling contact fatigue tests were conducted to find the effect of precision hard turning. The tests showed that hard turning provides as good a fatigue performance as grinding. Hard turning produces compressive residual stresses in a deep subsurface, which contribute to a long fatigue life. The effect of cutting parameters on residual stress was investigated in order to find why

  17. Valuing Stillbirths.

    PubMed

    Phillips, John; Millum, Joseph

    2015-07-01

    Estimates of the burden of disease assess the mortality and morbidity that affect a population by producing summary measures of health such as quality-adjusted life years (QALYs) and disability-adjusted life years (DALYs). These measures typically do not include stillbirths (fetal deaths occurring during the later stages of pregnancy or during labor) among the negative health outcomes they count. Priority-setting decisions that rely on these measures are therefore likely to place little value on preventing the more than three million stillbirths that occur annually worldwide. In contrast, neonatal deaths, which occur in comparable numbers, have a substantial impact on burden of disease estimates and are commonly seen as a pressing health concern. In this article we argue in favor of incorporating unintended fetal deaths that occur late in pregnancy into estimates of the burden of disease. Our argument is based on the similarity between late-term fetuses and newborn infants and the assumption that protecting newborns is important. We respond to four objections to counting stillbirths: (1) that fetuses are not yet part of the population and so their deaths should not be included in measures of population health; (2) that valuing the prevention of stillbirths will undermine women's reproductive rights; (3) that including stillbirths implies that miscarriages (fetal deaths early in pregnancy) should also be included; and (4) that birth itself is in fact ethically significant. We conclude that our proposal is ethically preferable to current practice and, if adopted, is likely to lead to improved decisions about health spending. PMID:25395144

  18. Virial coefficients and equations of state for mixtures of hard discs, hard spheres and hard hyperspheres

    NASA Astrophysics Data System (ADS)

    Santos, A.; Yuste, S. B.; López de Haro, M.

    The composition-independent virial coefficients of a d-dimensional binary mixture of (additive) hard hyperspheres following from a recent proposal for the equation of state of the mixture (SANTOS, A., YUSTE, S. B., and LÓPEZ DE HARO, M., 1999, Molec. Phys., 96 , 1) are examined. Good agreement between theoretical estimates and available exact or numerical results is found for d = 2, 3, 4 and 5, except for mixtures whose components are very disparate in size. A slight modification that remedies this deficiency is introduced and the resummation of the associated virial series is carried out, leading to a new proposal for the equation of state. The case of binary hard sphere mixtures (d = 3) is analysed in some detail.

  19. Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers

    E-print Network

    Northern British Columbia, University of

    Hard Questions 1 When Hard Questions are Asked: Evaluating Writing Centers James H. Bell University of Northern British Columbia 3333 University Way Prince George, BC Canada V2N 4Z9 RUNNING HEAD: Hard Questions Reading and Learning. Thank you to three reviewers for their revision suggestions. #12;Hard Questions 2

  20. Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y

    E-print Network

    Ott, Albrecht

    Hard body amphiphiles at a hard wall JOSEPH M. BRADER1y , CHRISTIAN VON FERBER2 and MATTHIAS 2003) We investigate the structure of amphiphilic molecules exposed to a substrate that is modelled by a hard wall. Our simple model amphiphiles consist of a hard sphere head group to which a vanishingly thin

  1. Depletion effects in smectic phases of hard-rod-hard-sphere mixtures.

    PubMed

    Martínez-Ratón, Y; Cinacchi, G; Velasco, E; Mederos, L

    2006-10-01

    It is known that when hard spheres are added to a pure system of hard rods the stability of the smectic phase may be greatly enhanced, and that this effect can be rationalised in terms of depletion forces. In the present paper we first study the effect of orientational order on depletion forces in this particular binary system, comparing our results with those obtained adopting the usual approximation of considering the rods parallel and their orientations frozen. We consider mixtures with rods of different aspect ratios and spheres of different diameters, and we treat them within Onsager theory. Our results indicate that depletion effects, and consequently smectic stability, decrease significantly as a result of orientational disorder in the smectic phase when compared with corresponding data based on the frozen-orientation approximation. These results are discussed in terms of the tau parameter, which has been proposed as a convenient measure of depletion strength. We present closed expressions for tau, and show that it is intimately connected with the depletion potential. We then analyse the effect of particle geometry by comparing results pertaining to systems of parallel rods of different shapes (spherocylinders, cylinders and parallelepipeds). We finally provide results based on the Zwanzig approximation of a fundamental-measure density-functional theory applied to mixtures of parallelepipeds and cubes of different sizes. In this case, we show that the tau parameter exhibits a linear asymptotic behaviour in the limit of large values of the hard-rod aspect ratio, in conformity with Onsager theory, as well as in the limit of large values of the ratio of rod breadth to cube side length, d, in contrast to Onsager approximation, which predicts tau approximately d (3). Based on both this result and the Percus-Yevick approximation for the direct correlation function for a hard-sphere binary mixture in the same limit of infinite asymmetry, we speculate that, for spherocylinders and spheres, the tau parameter should be of order unity as d tends to infinity. PMID:17171313

  2. The Hard Problem of Cooperation

    PubMed Central

    Eriksson, Kimmo; Strimling, Pontus

    2012-01-01

    Based on individual variation in cooperative inclinations, we define the “hard problem of cooperation” as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring and sanctions? In a laboratory experiment we find that the answer is affirmative if the institution is imposed on the group but negative if development of the institution is left to the group to vote on. In the experiment, participants were divided into groups of either cooperative types or non-cooperative types depending on their behavior in a public goods game. In these homogeneous groups they repeatedly played a public goods game regulated by an institution that incorporated several of the key properties identified by Ostrom: operational rules, monitoring, rewards, punishments, and (in one condition) change of rules. When change of rules was not possible and punishments were set to be high, groups of both types generally abided by operational rules demanding high contributions to the common good, and thereby achieved high levels of payoffs. Under less severe rules, both types of groups did worse but non-cooperative types did worst. Thus, non-cooperative groups profited the most from being governed by an institution demanding high contributions and employing high punishments. Nevertheless, in a condition where change of rules through voting was made possible, development of the institution in this direction was more often voted down in groups of non-cooperative types. We discuss the relevance of the hard problem and fit our results into a bigger picture of institutional and individual determinants of cooperative behavior. PMID:22792282

  3. Sampling hard to reach populations.

    PubMed

    Faugier, J; Sargeant, M

    1997-10-01

    Studies on 'hidden populations', such as homeless people, prostitutes and drug addicts, raise a number of specific methodological questions usually absent from research involving known populations and less sensitive subjects. This paper examines the advantages and limitations of nonrandom methods of data collection such as snowball sampling. It reviews the currently available literature on sampling hard to reach populations and highlights the dearth of material currently available on this subject. The paper also assesses the potential for using these methods in nursing research. The sampling methodology used by Faugier (1996) in her study of prostitutes, HIV and drugs is used as a current example within this context. PMID:9354993

  4. Hard and Soft Safety Verifications

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Anderson, Brenda

    2012-01-01

    The purpose of this paper is to examine the differences between and the effects of hard and soft safety verifications. Initially, the terminology should be defined and clarified. A hard safety verification is datum which demonstrates how a safety control is enacted. An example of this is relief valve testing. A soft safety verification is something which is usually described as nice to have but it is not necessary to prove safe operation. An example of a soft verification is the loss of the Solid Rocket Booster (SRB) casings from Shuttle flight, STS-4. When the main parachutes failed, the casings impacted the water and sank. In the nose cap of the SRBs, video cameras recorded the release of the parachutes to determine safe operation and to provide information for potential anomaly resolution. Generally, examination of the casings and nozzles contributed to understanding of the newly developed boosters and their operation. Safety verification of SRB operation was demonstrated by examination for erosion or wear of the casings and nozzle. Loss of the SRBs and associated data did not delay the launch of the next Shuttle flight.

  5. Measurements of the hard-x-ray reflectivity of iridium

    SciTech Connect

    Romaine, S.; Bruni, R.; Gorenstein, P.; Zhong, Z

    2007-01-10

    In connection with the design of a hard-x-ray telescope for the Constellation X-Ray Observatory we measured the reflectivity of an iridium-coated zerodur substrate as a function of angle at 55, 60, 70, and 80 keV at the National Synchrotron Light Source of Brookhaven National Laboratory. The optical constants were derived from the reflectivity data. The real component of the index of refraction is in excellent agreement with theoretical values at all four energies. However, the imaginary component, which is related to the mass attenuation coefficient, is 50% to 70% larger at 55, 60, and 70 keV than theoretical values.

  6. A scaling rule of indentation hardness of semiconductors

    NASA Astrophysics Data System (ADS)

    Yonenaga, Ichiro; Suzuki, Takayoshi

    2003-03-01

    We report a scaling rule of the indentation hardness of semiconductor crystals from room temperature to their melting. The Vickers hardness of fifteen semiconductors, Si, Ge, SiC, AlN, GaN, GaP, GaAs, GaSb, InP, InAs, InSb, ZnO, ZnSe, ZnTe and CdTe, has been investigated from room temperature to their melting points. The temperature dependences of the hardness H v of eleven of these semiconductors, namely those with a cubic structure, obey a universal relationship when H v and the temperature T are scaled respectively by the shear modulus G and by G b ^3 / k _B, with b being the magnitude of the Burgers vector and k B the Boltzmann constant. The scaling rule is the same as that found for the temperature dependence of the critical shear stress ? c for the 111 < 1bar1 0> slip system. The result leads a link between hardness and macroscopic yielding (dislocation motion). The relationshipH v = (70 ˜ 100) ? c is deduced for the cubic semiconductors is about ten times as large as the value for metals.

  7. Principal-value resummation for dilepton production

    SciTech Connect

    Contopanagos, H. [Argonne National Lab., IL (United States); Alvero, L.; Sterman, G. [State Univ. of New York, Stony Brook, NY (United States). Inst. for Theoretical Physics

    1994-10-01

    We present a new method of resummation of QCD threshold distributions to the hard scattering function of the dilepton production cross section in hadron-hadron collisions. Our formulation by-passes the infrared singularities of the QCD running coupling through a principal value prescription, and does not require an explicit infrared cut-off. The resulting large corrections exponentiate, and we discuss asymptotic properties of the exponent. We present a closed analytical formula for the resummed hard part in momentum space, and give predictions, at fixed-target energies, for the resulting cross section which is a bounded function of its kinematic variables in the entire partonic phase space.

  8. Effect of load on the hardness of hot isostatically pressed silicon nitride

    SciTech Connect

    Berriche, R.; Holt, R.T. (National Research Council, Ottawa, Ontario (Canada))

    1993-06-01

    The hardness values of five hot isostatic pressed silicon nitride materials, with varying densities, were measured at loads between 1 and 200 N. For the fully dense materials, the calculated hardness decreased from about 30 to 15 GPa as the load increased to about 10 N, and the hardness remained constant at higher loads. For the samples that showed indentation size effect (ISE), cracks formed at the corners of the indentation, starting at the lowest load of 1 N. Materials with lower densities had lower hardness values, displayed a very small or no ISE, and formed corner cracks only at high loads. For the samples that displayed an ISE at low loads, the formation of cracks was analyzed using the Niihara et al. criterion for Palmqvist cracks.

  9. Time Analysis of Hard Drive Imaging Tools

    Microsoft Academic Search

    Jack Wesley Riley; David A. Dampier; Rayford B. Vaughn

    2008-01-01

    Computer hard drives often contain evidence that is vital to digital forensic investigations. However, an authenticated working\\u000a copy or “forensic image” of a suspect hard drive must be created before any data can be analyzed. As the capacities of modern\\u000a hard drives increase, the time taken to create a forensic image, let alone analyze the data, increases significantly. This\\u000a paper

  10. Radial variations in modulus and hardness in SCS-6 silicon carbide fibers

    SciTech Connect

    Mann, A.B.; Weihs, T.P. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering; Balooch, M.; Kinney, J.H. [Lawrence Livermore National Lab., CA (United States). Dept. of Chemistry and Materials Science

    1999-01-01

    The mechanical properties of SCS-6 SiC fibers were measured as a function of fiber radius using nanoindentation techniques. Hardness and Young`s modulus were characterized for the material in all of the major regions of these fibers: the carbon core, the graphitic core coating, the inner SiC sheath, and the outer SiC sheath. The carbon core of the fibers was determined to be uniform in properties but extremely compliant. Young`s modulus of 28 GPa and a hardness of 4.2 GPa were measured. The graphitic core coating was found to exhibit considerable anelasticity and to have both a low modulus (21 GPa) and a low hardness (1.7 GPa). The inner sheath of the fiber, which contained a varying chemistry, showed a sharp increase in stiffness and hardness from the inner core. Modulus and hardness increased by an order of magnitude over just 1 or 2 {micro}m when transversing radially away from the core into the SiC. This change in properties was pronounced and clearly defined. The outer sheath, which contained a uniform chemistry and microstructure, was consistently stiff and hard when transversing radially. The average modulus and hardness for the full fiber was 333 GPa. The values reported for Young`s modulus and hardness clearly showed that the mechanical properties of SCS SiC fibers exhibit dramatic changes across their diameters.

  11. Some observations on hardness measurements of particulate-reinforced 6061 aluminum metal matrix composites

    NASA Astrophysics Data System (ADS)

    Das, T.; Bandyopadhyay, S.; Blairs, S.

    1992-12-01

    Hardness measurements on a series of particulate- reinforced metal matrix composites in a solution treated and T- 6 condition were carried out using a Vickers microhardness tester at 25-, 50-, 100-, 200-, 300-, and 500-g indenter loads and a Vickers macrohardness tester at an indenter load of 5 kg. It appears that the presence of the particles makes a contribution to the hardness measurement, the degree of which depends on the size and distribution of the particles, and also the indentation load. Although some trends are observed, there is no predictable effect of the material and test parameter on the hardness values.

  12. Resummation for QCD Hard Scattering

    E-print Network

    Kidonakis, N; Kidonakis, Nikolaos; Sterman, George

    1997-01-01

    We resum distributions that are singular at partonic threshold (the elastic limit) in heavy quark production, in terms of logarithmic behavior in moment space. The method may be applied to a variety of cross sections sensitive to the edge of phase space, including transverse momentum distributions. Beyond leading logarithm, dependence on the moment variable is controlled by a matrix renormalization group equation, reflecting the evolution of composite operators that represent the color structure of the underlying hard scattering. At next-to-leading logarithmic accuracy, these evolution equations may be diagonalized, and moment dependence in the cross section is a sum of exponentials. Beyond next-to-leading logarithm, resummation involves matrix-ordering. We give a detailed analysis for the case of heavy quark production by light quark annihilation and gluon fusion.

  13. Development of radiation hard scintillators

    SciTech Connect

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G. (Fermi National Accelerator Lab., Batavia, IL (United States)); Blackburn, R. (Michigan Univ., Nuclear Reactor Lab., Ann Arbor, MI (United States))

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro.

  14. TOXICITY OF COPPER TO CUTTHROAT TROUT ('SALMO CLARKI') UNDER DIFFERENT CONDITIONS OF ALKALINITY, PH, AND HARDNESS

    EPA Science Inventory

    Median lethal concentration (96-h LC50) values for acute copper toxicity to 3-10 g cutthroat trout (Salmo clarki) have been determined for nine different combinations of alkalinity, hardness, and pH. Equilibrium calculations were performed on the copper LC50 values; seven differe...

  15. Electromagnetic Scattering from Foliage Camouflaged Hard Targets,

    E-print Network

    Sarabandi, Kamal

    Electromagnetic Scattering from Foliage Camouflaged Hard Targets, in VHF-band Mojtaba Dehmollaian. Then using this formulation, and single scattering theory the backscattered field from a camouflaged complex

  16. Reference instrument of the VNIIM system for measuring hardness by the Vickers and Brinell methods

    Microsoft Academic Search

    N. P. Slavina

    1964-01-01

    If the calibration conditions are met, namely, the tip propagation speed under load is maintained at 0.2 mm\\/sec, the exposure time under load at 30 sec, and the ambient temperature at 20±2°C, the instrument can be recommended for reference measurements ensuring the reproduction of the hardness scale values and the calibration of hardness gauges with a mean square error not

  17. Influence of design variables on radiation hardness of silicon MINP solar cells

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.; Solaun, S.; Rao, B. B.; Banerjee, S.

    1985-01-01

    Metal-insulator-N/P silicon (MINP) solar cells were fabricated using different substrate resistivity values, different N-layer designs, and different I-layer designs. A shallow junction into an 0.3 ohm-cm substrate gave best efficiency whereas a deeper junction into a 1 to 4 ohm-cm substrate gave improved radiation hardness. I-layer design variation did little to influence radiation hardness.

  18. Modeling the turn-off of IGBT's in hard- and soft-switching applications

    Microsoft Academic Search

    Malay Trivedi; Krishna Shenai

    1997-01-01

    The turn-off of IGBTs in hard- and soft-switching converters is analyzed using nonquasi-static analysis. It is shown that while the turn-off current waveform for hard-switching is governed solely by the device for a particular value of on-state current and bus voltage, turn-off current waveform for soft-switching is strongly dependent on device-circuit interactions, so that a trade-off between turn-off loss and

  19. Characterization of ultra-hard silicon carbide coatings deposited by RF magnetron sputtering

    Microsoft Academic Search

    A. K Costa; S. S Camargo; C. A Achete; R Carius

    2000-01-01

    Silicon carbide films were deposited onto crystalline silicon substrates from a sintered SiC target using a RF magnetron sputtering system. The influence of substrate temperature (150–500°C) and polarization (0?100 V), Ar pressure (0.05–4 Pa) and RF power (50–400 W) on the mechanical properties (hardness and stress) of the resulting films was studied. Films with hardness values larger than 40 GPa

  20. Prediction of a Structural Transition in the Hard Disk Fluid

    E-print Network

    Jaroslaw Piasecki; Piotr Szymczak; John J. Kozak

    2010-09-16

    Starting from the second equilibrium equation in the BBGKY hierarchy under the Kirkwood superposition closure, we implement a new method for studying the asymptotic decay of correlations in the hard disk fluid in the high density regime. From our analysis and complementary numerical studies, we find that exponentially damped oscillations can occur only up to a packing fraction {\\eta}*~0.718, a value which is in substantial agreement with the packing fraction, {\\eta}~0.723, believed to characterize the transition from the ordered solid phase to a dense fluid phase, as inferred from Mak's Monte Carlo simulations [Phys. Rev. E 73, 065104 (2006)]. We next show that the same method of analysis predicts that exponential damping of oscillations in the hard sphere fluid becomes impossible when \\lambda = 4n\\pi {\\sigma}^3 [1 + H(1)]>/- 34.81, where H(1) is the contact value of the correlation function, n is the number density and {\\sigma} is the sphere diameter, in exact agreement with the condition, \\lambda >/- 34.8, first reported in a numerical study of the Kirkwood equation by Kirkwood et al. [J. Chem. Phys. 18, 1040 (1950)]. Finally, we show that our method confirms the absence of any structural transition in hard rods for the entire range of densities below close packing.

  1. Investigation of Specificity of Mechanical Properties of Hard Materials on Nanoscale with Use of SPM- Nanohardness Tester

    NASA Astrophysics Data System (ADS)

    Lvova, N. A.; Blank, V. D.; Gogolinskiy, K. V.; Kulibaba, V. F.

    2007-04-01

    Specifisities of deformation on nanoscale of hard brittle materials with the hardness exceeding 10 GP by means of scanning probe microscope - nanohardness tester "NanoScan" are investigated. It is found, that pile-up is forming at scratching of sample surface with use of diamond indenter. Heigh of this pile-up depends on hardness and elastic modulus of the material. Definition of the contact area without taking into account height of pile-up leads to an overestimation of hardness values. At scratching of silicon carbide surface a transition from plastic flow to fracture is found out. The results received allowed to estimate fracture toughness KIC for silicon carbide.

  2. Interfacial free energy of a hard-sphere fluid in contact with curved hard surfaces

    E-print Network

    Laird, Brian Bostian; Hunter, Allie; Davidchack, Ruslan L.

    2012-12-20

    Using molecular-dynamics simulation, we have calculated the interfacial free energy ? between a hard-sphere fluid and hard spherical and cylindrical colloidal particles, as functions of the particle radius R and the fluid ...

  3. Phonon contribution to the entropy of hard-sphere crystals

    NASA Astrophysics Data System (ADS)

    Elser, Veit

    2014-05-01

    Comparing the entropies of hard spheres in the limit of close packing, for different stacking sequences of the hexagonal layers, has been a challenge because the differences are so small. Here we present a method based on a "sticky-sphere" model by which the system interpolates between hard spheres in one limit and a harmonic crystal in the other. For the fcc and hcp stackings we have calculated the entropy difference in the harmonic (sticky) limit, as well as the differences in the free energy change upon removing the stickiness in the model. The former, or phonon entropy, accounts for most of the entropy difference. Our value for the net entropy difference, ?s =0.001164(8)kB per sphere, is in excellent agreement with the best previous estimate by Mau and Huse [Phys. Rev. E 59, 4396 (1999), 10.1103/PhysRevE.59.4396].

  4. Estimate of snow density knowing grain and share hardness

    NASA Astrophysics Data System (ADS)

    Valt, Mauro; Cianfarra, Paola; Cagnati, Anselmo; Chiambretti, Igor; Moro, Daniele

    2010-05-01

    Alpine avalanche warning services produces, weekly, snow profiles. Usually such profiles are made in horizontal snow fields, homogenously distributed by altitude and climatic micro-areas. Such profile allows grain shape, dimension and hardness (hand test) identification. Horizontal coring of each layer allows snow density identification. Such data allows the avalanche hazard evaluation and an estimation of the Snow Water Equivalent (SWE). Nevertheless the measurement of snow density, by coring, of very thin layers (less than 5 cm of thickness) is very difficult and are usually not measured by snow technicians. To bypass such problems a statistical analysis was performed to assign density values also to layers which cannot be measured. This system allows, knowing each layer thickness and its density, to correctly estimate SWE. This paper presents typical snow density values for snow hardness values and grain types for the Eastern Italian Alps. The study is based onto 2500 snow profiles with 17000 sampled snow layers from the Dolomites and Venetian Prealps (Eastern Alps). The table of typical snow density values for each grain type is used by YETI Software which elaborate snow profiles and automatically evaluate SWE. This method allows a better use of Avalanche Warning Services datasets for SWE estimation and local evaluation of SWE yearly trends for each snow field.

  5. Monte Carlo computer simulation of sedimentation of charged hard spherocylinders.

    PubMed

    Viveros-Méndez, P X; Gil-Villegas, Alejandro; Aranda-Espinoza, S

    2014-07-28

    In this article we present a NVT Monte Carlo computer simulation study of sedimentation of an electroneutral mixture of oppositely charged hard spherocylinders (CHSC) with aspect ratio L/? = 5, where L and ? are the length and diameter of the cylinder and hemispherical caps, respectively, for each particle. This system is an extension of the restricted primitive model for spherical particles, where L/? = 0, and it is assumed that the ions are immersed in an structureless solvent, i.e., a continuum with dielectric constant D. The system consisted of N = 2000 particles and the Wolf method was implemented to handle the coulombic interactions of the inhomogeneous system. Results are presented for different values of the strength ratio between the gravitational and electrostatic interactions, ? = (mg?)/(e(2)/D?), where m is the mass per particle, e is the electron's charge and g is the gravitational acceleration value. A semi-infinite simulation cell was used with dimensions Lx ? Ly and Lz = 5Lx, where Lx, Ly, and Lz are the box dimensions in Cartesian coordinates, and the gravitational force acts along the z-direction. Sedimentation effects were studied by looking at every layer formed by the CHSC along the gravitational field. By increasing ?, particles tend to get more packed at each layer and to arrange in local domains with an orientational ordering along two perpendicular axis, a feature not observed in the uncharged system with the same hard-body geometry. This type of arrangement, known as tetratic phase, has been observed in two-dimensional systems of hard-rectangles and rounded hard-squares. In this way, the coupling of gravitational and electric interactions in the CHSC system induces the arrangement of particles in layers, with the formation of quasi-two dimensional tetratic phases near the surface. PMID:25084954

  6. MAKING JAVA HARD REALTIME Peter Puschner

    E-print Network

    MAKING JAVA HARD REAL­TIME Peter Puschner Institut fË?ur Technische Informatik Technische Universit,andyg@cs.york.ac.uk ABSTRACT Due to its portability and security the Java program­ ming language has become very popular. Standard Java is however not suited for programming hard real­time sys­ tems. To overcome this limitation

  7. Hardness variability in commercial and hardened technologies

    Microsoft Academic Search

    M. R. Shaneyfelt; P. S. Winokur; T. L. Meisenheimer; F. W. Sexton; S. B. Roeske; M. G. Knoll

    1994-01-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is 'built-in' through statistical process control (SPC) of technology parameters relevant to the radiation

  8. Hard Spring Wheat Technical Committee, 2008 Crop.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eleven hard spring wheat lines that were developed by breeders throughout the spring wheat region of the U. S. were grown at up to five locations in 2008 and evaluated for kernel, milling, and bread baking quality against the check variety Glenn. Samples of wheat were milled at the USDA Hard Red Sp...

  9. Hard Metal Alveolitis Accompanied by Rheumatoid Arthritis

    Microsoft Academic Search

    Paula A. Hahtola; Ritva E. Järvenpää; Kari Lounatmaa; Jorma J. Mattila; Immo Rantala; Jukka A. Uitti; Seppo Sutinen

    2000-01-01

    Hard metal lung diseases (HML) are rare, and complex to diagnose. We describe the case of a patient with allergic alveolitis accompanied by rheumatoid arthritis. A sharpener of hard metal by trade, our patient was a 45-year-old, nonsmoking Caucasian female who experienced symptoms of cough and phlegm, and dyspnea on exertion. Preliminary lung findings were inspiratory rales in both basal

  10. Roller burnishing of hard turned surfaces

    Microsoft Academic Search

    F. Klocke; J. Liermann

    1998-01-01

    In a hard roller burnishing operation, a hydrostatically borne ceramic ball rolls over the component surface under high pressures. The roughness peaks are flattened and the quality of the workpiece surface is improved. When combined with hard turning, this process provides a manufacturing alternative to grinding and honing operations.The studies determined optimum working parameter ranges. Parameter settings were shown to

  11. Radiation hardness studies of CVD diamond detectors

    Microsoft Academic Search

    C. Bauer; I. Baumann; C. Colledani; J. Conway; P. Delpierre; F. Djama; W. Dulinski; A. Fallou; K. K. Gan; R. S. Gilmore; E. Grigoriev; G. Hallewell; S. Han; T. Hessing; K. Honschied; J. Hrubec; D. Husson; H. Kagan; D. Kania; R. Kass; W. Kinnison; K. T. Knöpfle; M. Krammer; T. J. Llewellyn; P. F. Manfredi; L. S. Pan; H. Pernegger; M. Pernicka; R. Plano; V. Re; S. Roe; A. Rudge; M. Schaeffer; S. Schnetzer; S. Somalwar; V. Speziali; R. Stone; R. J. Tapper; R. Tesarek; W. Trischuk; R. Turchetta; G. B. Thomson; R. Wagner; P. Weilhammer; C. White; H. Ziock; M. Zoeller

    1995-01-01

    The inherent properties of diamond make it an ideal material for tracking detectors especially in the high rate, high radiation environments of future colliders such as the LHC. In order to survive in this environment, detectors must be radiation hard. We have constructed charged particle detectors using high quality CVD diamond and performed radiation hardness tests on them. The signal

  12. Hardness, elastic modulus, and structure of very hard carbon films produced by cathodic-arc deposition with substrate pulse biasing

    SciTech Connect

    Pharr, G.M.; Callahan, D.L.; McAdams, S.D.; Tsui, T.Y. [Department of Materials Science, Rice University, Houston, Texas 77251-1892 (United States)] [Department of Materials Science, Rice University, Houston, Texas 77251-1892 (United States); Anders, S.; Anders, A.; Ager, J.W. III; Brown, I.G. [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Bhatia, C.S. [IBM Corporation, San Jose, California 95193 (United States)] [IBM Corporation, San Jose, California 95193 (United States); Silva, S.R.; Robertson, J. [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)] [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    1996-02-01

    The hardness, elastic modulus, and structure of several amorphous carbon films on silicon prepared by cathodic-arc deposition with substrate pulse biasing have been examined using nanoindentation, energy loss spectroscopy (EELS), and cross-sectional transmission electron microscopy. EELS analysis shows that the highest {ital sp}{sup 3} contents (85{percent}) and densities (3.00 g/cm{sup 3}) are achieved at incident ion energies of around 120 eV. The hardness and elastic modulus of the films with the highest {ital sp}{sup 3} contents are at least 59 and 400 GPa, respectively. These values are conservative lower estimates due to substrate influences on the nanoindentation measurements. The films are predominantly amorphous with a {approximately}20 nm surface layer which is structurally different and softer than the bulk. {copyright} {ital 1996 American Institute of Physics.}

  13. Phase diagram of hard tetrahedra.

    PubMed

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon C

    2011-11-21

    Advancements in the synthesis of faceted nanoparticles and colloids have spurred interest in the phase behavior of polyhedral shapes. Regular tetrahedra have attracted particular attention because they prefer local symmetries that are incompatible with periodicity. Two dense phases of regular tetrahedra have been reported recently. The densest known tetrahedron packing is achieved in a crystal of triangular bipyramids (dimers) with a packing density of 4000/4671 ? 85.63%. In simulation a dodecagonal quasicrystal is observed; its approximant, with periodic tiling (3.4.3(2).4), can be compressed to a packing fraction of 85.03%. Here, we show that the quasicrystal approximant is more stable than the dimer crystal for packing densities below 84% using Monte Carlo computer simulations and free energy calculations. To carry out the free energy calculations, we use a variation of the Frenkel-Ladd method for anisotropic shapes and thermodynamic integration. The enhanced stability of the approximant can be attributed to a network substructure, which maximizes the free volume (and hence the wiggle room) available to the particles and facilitates correlated motion of particles, which further contributes to entropy and leads to diffusion for packing densities below 65%. The existence of a solid-solid transition between structurally distinct phases not related by symmetry breaking--the approximant and the dimer crystal--is unusual for hard particle systems. PMID:22112060

  14. Phase Diagram of Hard Tetrahedra

    E-print Network

    Amir Haji-Akbari; Michael Engel; Sharon C. Glotzer

    2011-11-22

    Advancements in the synthesis of faceted nanoparticles and colloids have spurred interest in the phase behavior of polyhedral shapes. Regular tetrahedra have attracted particular attention because they prefer local symmetries that are incompatible with periodicity. Two dense phases of regular tetrahedra have been reported recently. The densest known tetrahedron packing is achieved in a crystal of triangular bipyramids (dimers) with packing density 4000/4671=85.63%. In simulation a dodecagonal quasicrystal is observed; its approximant, with periodic tiling (3.4.3^2.4), can be compressed to a packing fraction of 85.03%. Here, we show that the quasicrystal approximant is more stable than the dimer crystal for packing densities below 84% using Monte Carlo computer simulations and free energy calculations. To carry out the free energy calculations, we use a variation of the Frenkel-Ladd method for anisotropic shapes and thermodynamic integration. The enhanced stability of the approximant can be attributed to a network substructure, which maximizes the free volume (and hence the 'wiggle room') available to the particles and facilitates correlated motion of particles, which further contributes to entropy and leads to diffusion for packing densities below 65%. The existence of a solid-solid transition between structurally distinct phases not related by symmetry breaking -- the approximant and the dimer crystal-- is unusual for hard particle systems.

  15. Revisit of interfacial free energy of the hard sphere system near hard wall

    E-print Network

    Mingcheng Yang; Hongru Ma

    2008-06-23

    We propose a simple Monte Carlo method to calculate the interfacial free energy between the substrate and the material. Using this method we investigate the interfacial free energys of the hard sphere fluid and solid phases near a smooth hard wall. According to the obtained interfacial free energys of the coexisting fluid and solid phases and the Young equation we are able to determine the contact angle with high accuracy, cos$\\theta$ = 1:010(31), which indicates that a smooth hard wall can be wetted completely by the hard sphere crystal at the interface between the wall and the hard sphere fluid.

  16. Effects of water hardness on the toxicity of manganese to developing brown trout (Salmo trutta)

    SciTech Connect

    Stubblefield, W.A.; Garrison, T.D.; Hockett, J.R. [ENSR Corp., Fort Collins, CO (United States); Brinkman, S.F.; Davies, P.H.; McIntyre, M.W. [Colorado Div. of Wildlife, Fort Collins, CO (United States)

    1997-10-01

    Manganese is a common constituent of point and nonpoint discharges from mining and smelting activities. Available data indicate that Mn is acutely toxic at relatively high aqueous concentrations, when compared with trace metals, and its toxicity is affected by water hardness. Little information is available regarding the chronic toxicity of manganese. Early-life-stage (ELS) tests were conducted to determine the toxicity of manganese to brown trout (Salmo trutta) and to evaluate the extent to which water hardness (ranging from 30 to 450 mg/L as CaCO{sub 3}) affects the chronic toxicity of Mn. Water hardness of significantly affected Mn chronic toxicity, with toxicity decreasing with increasing hardness. Decreased survival was the predominant effect noted in the 30-mg/L hardness experiment, while significant effects on growth (as measured by changes in body weight) were observed in both the 150- and 450-mg/L hardness experiments. Twenty-five percent inhibition concentration (IC25) values, based on the combined endpoints (i.e., survival and body weight), were 4.67, 5.59, and 8.68 mg Mn/L (based on measured Mn concentration) at hardness levels of approximately 30, 150, and 450 mg/L as CaCO{sub 3}, respectively.

  17. A survey of hard spectrum ROSAT sources 1: X-ray source catalogue

    E-print Network

    M. J. Page; J. P. D. Mittaz; F. J. Carrera

    2000-06-24

    We present a catalogue of 147 serendipitous X-ray sources selected to have hard spectra (alpha 10 times as much effective area to hard sources as it has to soft sources above a 0.5 - 2 keV flux level of 10^-14 erg/cm^2/s. The distribution of best fit spectral slopes of the hard sources suggests that a typical ROSAT hard source in our survey has a spectral slope alpha ~0. The hard sources have a steep number flux relation (dN/dS propto S^-gamma with a best fit value of gamma = 2.72 +- 0.12) and make up about 15% of all 0.5 - 2 keV sources with S > 10^-14 erg/cm^2/s. If their N(S) continues to fainter fluxes, the hard sources will comprise ~ 40% of sources with 5 10^-15 < S < 10^-14. The population of hard sources can therefore account for the harder average spectra of ROSAT sources with S < 10^-14. They probably make a strong contribution to the X-ray background at faint fluxes and could be the solution to the X-ray background spectral paradox.

  18. Pion Form Factor in Chiral Limit of Hard-Wall AdS/QCD Model

    SciTech Connect

    Anatoly Radyushkin; Hovhannes Grigoryan

    2007-12-01

    We develop a formalism to calculate form factor and charge density distribution of pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic expressions for these functions and for the pion form factor. They allow to relate such observables as the pion decay constant and the pion charge electric radius to the values of chiral condensate and hard-wall cutoff scale. The evolution of the pion form factor to large values of the momentum transfer is discussed, and results are compared to existing experimental data.

  19. Characterization of Hard Piezoelectric Lead-Free Ceramics

    PubMed Central

    Zhang, Shujun; Lim, Jong Bong; Lee, Hyeong Jae; Shrout, Thomas R.

    2010-01-01

    K4CuNb8O23 doped K0.45Na0.55NbO3 (KNN-KCN) ferroelectric ceramics were found to exhibit asymmetrical polarization hysteresis loops, related to the development of an internal bias field. The internal bias field is believed to be the result of defect dipoles of acceptor ions and oxygen vacancies, which lead to piezoelectric “hardening” effect, by stabilizing and pinning of the domain wall motion. The dielectric loss for the hard lead-free piezoelectric ceramic was found to be 0.6%, with mechanical quality factors Q on the order of >1500. Furthermore, the piezoelectric properties were found to decrease and the coercive field increased, when compared with the undoped material, exhibiting a typical characteristic of “hard” behavior. The temperature usage range was limited by the polymorphic phase transition temperature, being 188°C. The full set of material constants was determined for the KNN-KCN materials. Compared with conventional hard PZT ceramics, the lead-free possessed lower dielectric and piezoelectric properties; however, comparable values of mechanical Q, dielectric loss, and coercive fields were obtained, making acceptor modified KNN based lead-free piezoelectric material promising for high-power applications, where lead-free materials are desirable. PMID:19686966

  20. Communication: Radial distribution functions in a two-dimensional binary colloidal hard sphere system

    NASA Astrophysics Data System (ADS)

    Thorneywork, Alice L.; Roth, Roland; Aarts, Dirk G. A. L.; Dullens, Roel P. A.

    2014-04-01

    Two-dimensional hard disks are a fundamentally important many-body model system in classical statistical mechanics. Despite their significance, a comprehensive experimental data set for two-dimensional single component and binary hard disks is lacking. Here, we present a direct comparison between the full set of radial distribution functions and the contact values of a two-dimensional binary colloidal hard sphere model system and those calculated using fundamental measure theory. We find excellent quantitative agreement between our experimental data and theoretical predictions for both single component and binary hard disk systems. Our results provide a unique and fully quantitative mapping between experiments and theory, which is crucial in establishing the fundamental link between structure and dynamics in simple liquids and glass forming systems.

  1. Communication: radial distribution functions in a two-dimensional binary colloidal hard sphere system.

    PubMed

    Thorneywork, Alice L; Roth, Roland; Aarts, Dirk G A L; Dullens, Roel P A

    2014-04-28

    Two-dimensional hard disks are a fundamentally important many-body model system in classical statistical mechanics. Despite their significance, a comprehensive experimental data set for two-dimensional single component and binary hard disks is lacking. Here, we present a direct comparison between the full set of radial distribution functions and the contact values of a two-dimensional binary colloidal hard sphere model system and those calculated using fundamental measure theory. We find excellent quantitative agreement between our experimental data and theoretical predictions for both single component and binary hard disk systems. Our results provide a unique and fully quantitative mapping between experiments and theory, which is crucial in establishing the fundamental link between structure and dynamics in simple liquids and glass forming systems. PMID:24784245

  2. Hard Gamma Ray Emission from the Starburst Galaxy NGC 253

    NASA Technical Reports Server (NTRS)

    Jackson, James M.; Marscher, Alan M.

    1996-01-01

    We have completed the study to search for hard gamma ray emission from the starburst galaxy NGC 253. Since supernovae are thought to provide the hard gamma ray emission from the Milky Way, starburst galaxies, with their extraordinarily high supernova rates, are prime targets to search for hard gamma ray emission. We conducted a careful search for hard gamma ray emission from NGC 253 using the archival data from the EGRET experiment aboard the CGRO. Because this starburst galaxy happens to lie near the South Galactic Pole, the Galactic gamma ray background is minimal. We found no significant hard gamma ray signal toward NGC 253, although a marginal signal of about 1.5 sigma was found. Because of the low Galactic background, we obtained a very sensitive upper limit to the emission of greater than 100 MeV gamma-rays of 8 x 10(exp -8) photons/sq cm s. Since we expected to detect hard gamma ray emission, we investigated the theory of gamma ray production in a dense molecular medium. We used a leaky-box model to simulate diffusive transport in a starburst region. Since starburst galaxies have high infrared radiation fields, we included the effects of self-Compton scattering, which are usually ignored. By modelling the expected gamma-ray and synchrotron spectra from NGC 253, we find that roughly 5 - 15% of the energy from supernovae is transferred to cosmic rays in the starburst. This result is consistent with supernova acceleration models, and is somewhat larger than the value derived for the Galaxy (3 - 10%). Our calculations match the EGRET and radio data very well with a supernova rate of 0.08/ yr, a magnetic field B approx. greater than 5 x 10(exp -5) G, a density n approx. less than 100/sq cm, a photon density U(sub ph) approx. 200 eV/sq cm, and an escape time scale tau(sub 0) approx. less than 10 Myr. The models also suggest that NGC 253 should be detectable with only a factor of 2 - 3 improvement in sensitivity. Our results are consistent with the standard picture of gamma-ray acceleration by supernovae.

  3. Equation of state of the hard-sphere crystal

    NASA Astrophysics Data System (ADS)

    Rascón, C.; Mederos, L.; Navascués, G.

    1996-06-01

    An approach to the averaged two-particle distribution function of a crystalline phase is presented. It includes an indirect check of the merit of the Gaussian approximation for the local density and a way to infer values of the thermodynamic variables from simulation data. The equation of state and the compressibility of the hard-sphere fcc crystal is computed from the Tarazona free energy density functional [Phys. Rev. A 31, 2672 (1985)]. They are in excellent agreement with simulation results over the physical range of densities up to almost close packing. We also include the comparison with the results obtained by two other functional approaches, which are also excellent.

  4. Phase diagram of the hard-sphere/attractive-Yukawa system

    NASA Astrophysics Data System (ADS)

    Mederos, L.; Navascués, G.

    1994-12-01

    A density functional approximation is used to study the phase diagram of a hard sphere-attractive Yukawa system. We pay special attention to the dependence of the liquid phase stability on the range of the attractive tail. When this is sufficiently short-ranged, the liquid phase is not present in the phase diagram. The transition to the usual behavior with a phase diagram showing vapor, liquid, and solid phases takes place for a value of the range of the attractive part which is in reasonable agreement with recent Monte Carlo simulations and theoretical results.

  5. Hard Equality Constrained Integer Knapsacks

    Microsoft Academic Search

    Karen Aardal; Arjen K. Lenstra

    2002-01-01

    Abstract We consider the following integer feasibility problem: “Given positive integer numbers,a0;a1;:::;an; with gcd(a1;:::;an) = 1 and a = (a1;:::;an), does there exist a vector x 2 Z, ‚0 satisfying ax,= a0?” We prove that if the coecients a1;:::;an have a certain decomposable structure, then the Frobenius number associated with a1;:::;an, i.e., the largest value of a0 for which ax

  6. Electronic Teaching: Hard Disks and Networks.

    ERIC Educational Resources Information Center

    Howe, Samuel F.

    1984-01-01

    Describes floppy-disk and hard-disk based networks, electronic systems linking microcomputers together for the purpose of sharing peripheral devices, and presents points to remember when shopping for a network. (MBR)

  7. One-dimensional gas of hard needles

    E-print Network

    Kardar, Mehran

    We study a one-dimensional gas of needlelike objects as a testing ground for a formalism that relates the thermodynamic properties of “hard” potentials to the probabilities for contacts between particles. Specifically, we ...

  8. Automated radiation hard ASIC design tool

    NASA Technical Reports Server (NTRS)

    White, Mike; Bartholet, Bill; Baze, Mark

    1993-01-01

    A commercial based, foundry independent, compiler design tool (ChipCrafter) with custom radiation hardened library cells is described. A unique analysis approach allows low hardness risk for Application Specific IC's (ASIC's). Accomplishments, radiation test results, and applications are described.

  9. Hard and flexible optical printed circuit board

    Microsoft Academic Search

    El-Hang Lee; Hyun Sik Lee; S. G. Lee; B. H. O; S. G. Park; K. H. Kim

    2007-01-01

    We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro\\/nano-scale optical wires, circuits

  10. EMP simulation for hardness verification testing

    NASA Astrophysics Data System (ADS)

    Beilfuss, J.; Capobianco, J.; Gray, R.

    A serious problem in the development of NEMP (nuclear electromagnetic pulse)-hardened systems is lack of adequate verification testing of the system hardness. The authors describe the development and use of a direct injection system designed specifically for threat-level hardness verification testing of complex systems with a number of electronic shelters interconnected by cables. Details of the theory and design of the synchronous injection system are presented. Experimental results related to the validity of the simulation technique are included.

  11. A Novel Approach to Hardness Testing

    NASA Technical Reports Server (NTRS)

    Spiegel, F. Xavier; West, Harvey A.

    1996-01-01

    This paper gives a description of the application of a simple rebound time measuring device and relates the determination of relative hardness of a variety of common engineering metals. A relation between rebound time and hardness will be sought. The effect of geometry and surface condition will also be discussed in order to acquaint the student with the problems associated with this type of method.

  12. Weakly Hard Real-Time Systems

    Microsoft Academic Search

    Guillem Bernat; Alan Burns; Albert Llamosí

    2001-01-01

    In a hard real-time system it is assumed that no deadline is missed, whereas in a softor rm real-time system deadlines can be missed, although, this usually happens in a nonpredictableway. However, most hard real-time systems could miss some deadlines providedthat it happens in a known and predictable way. Also adding predictability on the patternof missed deadlines for soft and

  13. RAD hard PROM design study

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The results of a preliminary study on the design of a radiation hardened fusible link programmable read-only memory (PROM) are presented. Various fuse technologies and the effects of radiation on MOS integrated circuits are surveyed. A set of design rules allowing the fabrication of a radiation hardened PROM using a Si-gate CMOS process is defined. A preliminary cell layout was completed and the programming concept defined. A block diagram is used to describe the circuit components required for a 4 K design. A design goal data sheet giving target values for the AC, DC, and radiation parameters of the circuit is presented.

  14. What's the Value in Value-Added?

    ERIC Educational Resources Information Center

    Duffrin, Elizabeth

    2011-01-01

    A growing number of school districts are adopting "value-added" measures of teaching quality to award bonuses or even tenure. And two competitive federal grants are spurring them on. Districts using value-added data are encouraged by the results. But researchers who support value-added measures advise caution. The ratings, which use a statistical…

  15. Time correlation functions of hard sphere and soft sphere fluids.

    PubMed

    Bra?ka, A C; Heyes, D M

    2004-02-01

    We explore the transition between soft particle fluids of increasing steepness to the hard sphere limit. We analyze the analytic forms of the time correlation functions used in determining transport coefficients in Green-Kubo formulas for fluids composed of particles interacting through a repulsive r(-n) potential. We focus on the steeply repulsive n--> infinity limit where the potential tends to the hard sphere interaction. Dufty [Mol. Phys. 100, 2331 (2002)] developed a theoretical framework that can be used to characterize the transition from a steeply repulsive continuous potential toward the hard sphere potential for the shear stress time correlation function. This function was shown to consist of a rapidly decaying contribution (which is singular in the steeply repulsive limit) and a slowly decaying nonsingular part which can be reasonably well represented by Enskog's prediction on times of order and in excess of the mean collision time. We extend this treatment to the bulk viscosity and thermal conductivity. We focus on the bulk viscosity (pressure) correlation function as it is purely singular for hard spheres, and has no kinetic or cross term contributions in this limit. There is no relaxation of this correlation function on the mean collision or Enskog time scale for hard spheres. We show that it is not possible to represent the steeply repulsive behavior of this function entirely in terms of a sech function, i.e., C(B)(t)=sech(a(n)t/tau(n)), where a(n) is a numerical factor, t is time, and tau(n) is a relaxation time proportional to n(-1). An additional singular function, which we call w(t), is required to obtain the correct short-time behavior of C(B)(t) and the Enskog value for the bulk viscosity. With this additional function, the value of a(n) in the n--> infinity limit is a(n)=square root of 2 which is consistent with the second moment of the time expansion of the time correlation function. We compute this function for large n and extrapolate it to n--> infinity, determining one possible analytic form. The shear stress correlation function also gives a(n)=square root of 2 in the hard sphere limit for the singular part when the sech and w functions are used. This function has a nonsingular component, even in the hard sphere limit. We explore various forms for the crossover function X(t/tau(n)) introduced by Dufty, which weights the limiting singular and nonsingular contributions to C(S)(t) particularly at intermediate times. The qualitative behavior for the heat flux time correlation function (used to obtain the thermal conductivity) is much the same as the shear case. The w(t) derived by several self-consistent extrapolations appears, within the simulation statistics, to be the same for the bulk and shear viscosity, and for the thermal conductivity cases. PMID:14995434

  16. From Lyapunov modes to the exponents for hard disk systems

    E-print Network

    Tony Chung; Daniel Truant; Gary P. Morriss

    2009-04-08

    We demonstrate the preservation of the Lyapunov modes by the underlying tangent space dynamics of hard disks. This result is exact for the zero modes and correct to order $\\epsilon$ for the transverse and LP modes where $\\epsilon$ is linear in the mode number. For sufficiently large mode numbers the dynamics no longer preserves the mode structure. We propose a Gram-Schmidt procedure based on orthogonality with respect to the centre space that determines the values of the Lyapunov exponents for the modes. This assumes a detailed knowledge of the modes, but from that predicts the values of the exponents from the modes. Thus the modes and the exponents contain the same information.

  17. Uniform shear flow in dissipative gases: computer simulations of inelastic hard spheres and frictional elastic hard spheres.

    PubMed

    Astillero, Antonio; Santos, Andrés

    2005-09-01

    In the preceding paper, we have conjectured that the main transport properties of a dilute gas of inelastic hard spheres (IHSs) can be satisfactorily captured by an equivalent gas of elastic hard spheres (EHSs), provided that the latter are under the action of an effective drag force and their collision rate is reduced by a factor (1+alpha)/2 (where alpha is the constant coefficient of normal restitution). In this paper we test the above expectation in a paradigmatic nonequilibrium state, namely, the simple or uniform shear flow, by performing Monte Carlo computer simulations of the Boltzmann equation for both classes of dissipative gases with a dissipation range 0.5 < or = alpha < or = 0.95 and two values of the imposed shear rate a. It is observed that the evolution toward the steady state proceeds in two stages: a short kinetic stage (strongly dependent on the initial preparation of the system) followed by a slower hydrodynamic regime that becomes increasingly less dependent on the initial state. Once conveniently scaled, the intrinsic quantities in the hydrodynamic regime depend on time, at a given value of alpha, only through the reduced shear rate a*(t) is proportional to a/square root(T(t)), until a steady state, independent of the imposed shear rate and of the initial preparation, is reached. The distortion of the steady-state velocity distribution from the local equilibrium state is measured by the shear stress, the normal stress differences, the cooling rate, the fourth and sixth cumulants, and the shape of the distribution itself. In particular, the simulation results seem to be consistent with an exponential overpopulation of the high-velocity tail. These properties are common to both the IHS and EHS systems. In addition, the EHS results are in general hardly distinguishable from the IHS ones if alpha approximately > 0.7, so that the distinct signature of the IHS gas (higher anisotropy and overpopulation) only manifests itself at relatively high dissipations. PMID:16241428

  18. Structural and relative stabilities, electronic properties, and hardness of iron tetraborides from first prinicples.

    PubMed

    Ding, Li-Ping; Kuang, Xiao-Yu; Shao, Peng; Huang, Xiao-Fen

    2014-04-01

    First-principles calculations were carried out to investigate the structure, phase stability, electronic property, and roles of metallicity in the hardness for recently synthesized FeB4 with various different structures. Our calculation indicates that the orthorhombic phase with Pnnm symmetry is the most energetically stable one. The other four new dynamically stable phases belong to space groups monoclinic C2/m, orthorhombic Pmmn, trigonal R3?m, and hexagonal P63/mmc. Their mechanical and thermodynamic stabilities are verified by calculating elastic constants, formation enthalpies, and phonon dispersions. We found that all phases are stabilized further under pressure. Above the pressure of about 50 GPa, the formation enthalpy of Pmmn is almost equal to that of P63/mmc phase. The analysis on density of states not only demonstrates that formation of strong covalent bonding in these compounds contributes greatly to their stabilities but also that they all exhibit metallic behavior which does not relate to the approach used. By considering metallic contributions, the estimated Vickers hardness values based on the semiempirical model show that the OsB4-structured FeB4, with a hardness of 48.1 GPa, well exceeding the limitation of superhardness (40 GPa), is more hard than the most stable phase. The others are predicted to be potential hard materials. Moreover, the atomic configuration and strong B-B covalent bonds are found to play important roles in the hardness of materials. PMID:24605919

  19. Geometrical characteristics of the enlarged fused hard sphere models of simple molecules.

    PubMed

    Boublík, Tomas

    2005-10-20

    The enlarged fused hard sphere model represents a compromise between fused hard sphere- and hard convex body models of repulsive interactions of nonspherical molecules. Geometric functionals of the enlarged fused hard sphere models, i.e., the hard body volume, surface area, and "mean radius" for 25 molecules of the linear and approximately planar shapes (cycloalkanes and aromatic compounds), neopentane and cyclohexane were determined from the bond lengths and bond angles and expressed in the dimensionless form. The hard sphere diameters, first approximated by the values found from the correlation of the second virial coefficients, were then adjusted to heats of vaporization of the studied compounds. Parameters of nonsphericity and molar volumes, evaluated from these characteristics, are compared with parameters of modern semiempirical equations of state (BACK, BACKONE, SAFT). The calculated geometric quantities for a series of compounds make it possible to improve methods of determining the characteristic parameters of the modern semiempirical equations of state, as well as those from the perturbation approaches. PMID:16853511

  20. Soft Power and Hard Measures: Large-Scale Assessment, Citizenship and the European Union

    ERIC Educational Resources Information Center

    Rutkowski, David; Engel, Laura C.

    2010-01-01

    This article explores the International Civic and Citizenship Education Study (ICCS) with particular emphasis on the European Union's (EU's) involvement in the regional portion. Using the ICCS, the EU actively combines hard measures with soft power, allowing the EU to define and steer cross-national rankings of values of EU citizenship. The…

  1. Note: equation of state and the freezing point in the hard-sphere model.

    PubMed

    Robles, Miguel; López de Haro, Mariano; Santos, Andrés

    2014-04-01

    The merits of different analytical equations of state for the hard-sphere system with respect to the recently computed high-accuracy value of the freezing-point packing fraction are assessed. It is found that the Carnahan-Starling-Kolafa and the branch-point approximant equations of state yield the best performance. PMID:24712819

  2. Note: Equation of state and the freezing point in the hard-sphere model

    NASA Astrophysics Data System (ADS)

    Robles, Miguel; López de Haro, Mariano; Santos, Andrés

    2014-04-01

    The merits of different analytical equations of state for the hard-sphere system with respect to the recently computed high-accuracy value of the freezing-point packing fraction are assessed. It is found that the Carnahan-Starling-Kolafa and the branch-point approximant equations of state yield the best performance.

  3. Experimental studies on the rheology of hard-sphere suspensions near the glass transition

    Microsoft Academic Search

    Louise. Marshall; Charles F. Zukoski

    1990-01-01

    We have investigated the rheological behavior of sterically stabilized colloidal silica particles of three different sizes at volume fractions above 0.5. Despite a small surface charge, which elevated the intrinsic viscosity from the Einstein value of 2.5, the particles were found to behave essentially as hard spheres in the concentrated suspensions and to have properties highly reminiscent of molecular glasses.

  4. Improvement of RRO using hybrid-type STW for hard disk drives

    Microsoft Academic Search

    Takahiro Inoue; Makoto Horisaki; Yousuke Seo; Shizuo Yamazaki

    2000-01-01

    Accurate servo track writers (STWs) are indispensable for hard disk drives (HDDs) with high track density. We have developed a prototype hybrid-type STW, which has two writing stages, and compared the servo patterns with those by the conventional STW. The experimental results are described showing that the hybrid-type STW reduces the maximum value of repeatable runout (RRO) by about 40%

  5. Evaluation of glass transition temperature and dynamic mechanical properties of autopolymerized hard direct denture reline resins.

    PubMed

    Takase, Kazuma; Watanabe, Ikuya; Kurogi, Tadafumi; Murata, Hiroshi

    2015-01-01

    This study assessed methods for evaluation of glass transition temperature (Tg) of autopolymerized hard direct denture reline resins using dynamic mechanical analysis and differential scanning calorimetry in addition to the dynamic mechanical properties. The Tg values of 3 different reline resins were determined using a dynamic viscoelastometer and differential scanning calorimeter, and rheological parameters were also determined. Although all materials exhibited higher storage modulus and loss modulus values, and a lower loss tangent at 37?C with a higher frequency, the frequency dependence was not large. Tg values obtained by dynamic mechanical analysis were higher than those by differential scanning calorimetry and higher frequency led to higher Tg, while more stable Tg values were also obtained by that method. These results suggest that dynamic mechanical analysis is more advantageous for characterization of autopolymerized hard direct denture reline resins than differential scanning calorimetry. PMID:25740164

  6. Hard-Core Unemployment: A Selected, Annotated Bibliography.

    ERIC Educational Resources Information Center

    Cameron, Colin, Comp.; Menon, Anila Bhatt, Comp.

    This annotated bibliography contains references to various films, articles, and books on the subject of hard-core unemployment, and is divided into the following sections: (1) The Sociology of the Hard-Core Milieu, (2) Training Programs, (3) Business and the Hard-Core, (4) Citations of Miscellaneous References on Hard-Core Unemployment, (5)…

  7. Boosting and HardCore Sets Adam R. Klivans

    E-print Network

    Servedio, Rocco

    Boosting and Hard­Core Sets Adam R. Klivans #3; Department of Mathematics MIT Cambridge, MA 02139­ retical computer science: hard­core set construction, a type of hardness amplification from computational that the hard­core set construction of Impagliazzo [15], which establishes the existence of dis­ tributions

  8. Hard or Soft Classification? Large-Margin Unified Machines

    E-print Network

    Liu, Yufeng

    Hard or Soft Classification? Large-Margin Unified Machines Yufeng LIU, Hao Helen ZHANG, and Yichao for classification problems. Among numerous classifiers, some are hard classifiers while some are soft ones. Soft-based classifiers including both hard and soft ones. By offering a natural bridge from soft to hard classification

  9. Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard

    E-print Network

    Moore, Simon

    Electromagnetic Analysis of Synchronous and Asynchronous Circuits using Hard Disc Heads Theo the magnetic field component ­ Inductive hard disc head (circa 1990) ­ Giant magnetoresistive hard disc head to `scope · Couldn't detect ALU activity, only bus traffic and clock on bond wires #12;Inductive hard disc

  10. Flavor Characterization of Breads Made from Hard Red Winter Wheat and Hard White Winter Wheat

    Microsoft Academic Search

    CHUN-YEN CHANG; EDGAR CHAMBERS

    Cereal Chem. 69(5):556-559 Sensory flavor profiles for white pan bread and whole wheat bread impression than did HRW crust. HRW crumb was sweeter and more made from hard red winter (HRW) or hard white winter (HWW) wheat dairylike than HWW crumb. HWW crumb had a phenoliclike note not were developed by a professionally trained panel. The flavors of crust present

  11. COMPARISON OF QUALITY CHARACTERISTICS AND BREADMAKING FUNCTIONALITY OF HARD RED WINTER AND HARD RED SPRING WHEAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various whole-kernel, milling, flour, dough, and breadmaking quality parameters were compared between hard red winter (HRW) and hard red spring (HRS) wheat. From the 43 quality parameters evaluated, only eight quality characteristics - test weight, moisture content, kernel size, polyphenol oxidase ...

  12. Fast Algorithms forFast Algorithms for Hard Graph Problems:Hard Graph Problems

    E-print Network

    Hajiaghayi, Mohammad

    vertex cover, dominating set, feedback vertex set, unweighted TSP, ... Or any graph optimization problem cover, dominating set, connected dominating set, r-dominating set, feedback vertex set, unweighted TSPFast Algorithms forFast Algorithms for Hard Graph Problems:Hard Graph Problems: Bidimensionality

  13. Hard Water and Soft Soap: Dependence of Soap Performance on Water Hardness

    ERIC Educational Resources Information Center

    Osorio, Viktoria K. L.; de Oliveira, Wanda; El Seoud, Omar A.; Cotton, Wyatt; Easdon, Jerry

    2005-01-01

    The demonstration of the performance of soap in different aqueous solutions, which is due to water hardness and soap formulation, is described. The demonstrations use safe, inexpensive reagents and simple glassware and equipment, introduce important everyday topics, stimulates the students to consider the wider consequences of water hardness and…

  14. Erosion testing of hard materials and coatings

    SciTech Connect

    Hawk, Jeffrey A.

    2005-04-29

    Erosion is the process by which unconstrained particles, usually hard, impact a surface, creating damage that leads to material removal and component failure. These particles are usually very small and entrained in fluid of some type, typically air. The damage that occurs as a result of erosion depends on the size of the particles, their physical characteristics, the velocity of the particle/fluid stream, and their angle of impact on the surface of interest. This talk will discuss the basics of jet erosion testing of hard materials, composites and coatings. The standard test methods will be discussed as well as alternative approaches to determining the erosion rate of materials. The damage that occurs will be characterized in genera1 terms, and examples will be presented for the erosion behavior of hard materials and coatings (both thick and thin).

  15. Potential Health Impacts of Hard Water

    PubMed Central

    Sengupta, Pallav

    2013-01-01

    In the past five decades or so evidence has been accumulating about an environmental factor, which appears to be influencing mortality, in particular, cardiovascular mortality, and this is the hardness of the drinking water. In addition, several epidemiological investigations have demonstrated the relation between risk for cardiovascular disease, growth retardation, reproductive failure, and other health problems and hardness of drinking water or its content of magnesium and calcium. In addition, the acidity of the water influences the reabsorption of calcium and magnesium in the renal tubule. Not only, calcium and magnesium, but other constituents also affect different health aspects. Thus, the present review attempts to explore the health effects of hard water and its constituents. PMID:24049611

  16. Debating Propositions of Value.

    ERIC Educational Resources Information Center

    Matlon, Ronald J.

    1978-01-01

    Advances a rationale for debating propositions of value in interscholastic contests. Considers implications for burden of proof, presumption, and the location of issues in value propositions, and proposes a preliminary system for the analysis of value propositions. (JMF)

  17. Universality of Hard-Loop Action

    E-print Network

    Alina Czajka; Stanislaw Mrowczynski

    2014-12-17

    The effective actions of gauge bosons, fermions and scalars, which are obtained within the hard-loop approximation, are shown to have unique forms for a whole class of gauge theories including QED, scalar QED, super QED, pure Yang-Mills, QCD, super Yang-Mills. The universality occurs irrespective of a field content of each theory and of variety of specific interactions. Consequently, the long-wavelength or semiclassical features of plasma systems governed by these theories such as collective excitations are almost identical. An origin of the universality, which holds within the limits of applicability of the hard-loop approach, is discussed.

  18. Degenerate quasicrystal of hard triangular bipyramids.

    PubMed

    Haji-Akbari, Amir; Engel, Michael; Glotzer, Sharon C

    2011-11-18

    We report a degenerate quasicrystal in Monte Carlo simulations of hard triangular bipyramids each composed of two regular tetrahedra sharing a single face. The dodecagonal quasicrystal is similar to that recently reported for hard tetrahedra [Haji-Akbari et al., Nature (London) 462, 773 (2009)] but degenerate in the pairing of tetrahedra, and self-assembles at packing fractions above 54%. This notion of degeneracy differs from the degeneracy of a quasiperiodic random tiling arising through phason flips. Free energy calculations show that a triclinic crystal is preferred at high packing fractions. PMID:22181897

  19. UV curable hard coatings on polyesters

    NASA Astrophysics Data System (ADS)

    Datashvili, Tea; Brostow, Witold; Kao, David

    2006-10-01

    UV curable, hard and transparent hybrid inorganic-organic coatings with covalent links between the inorganic and the organic networks were prepared using organically crosslinked heteropolysiloxanes based on the sol-gel process. The materials were applied onto polyester sheets and UV cured. The deposition was followed by a thermal treatment to improve mechanical properties of the coatings. High light transmission and the resulting thermophysical properties indicate the presence of a nanoscale hybrid composition. The coatings show excellent adhesion to polyesters even without using primers. Further mechanical characterization shows that the coatings provide high hardness and good abrasion resistance.

  20. Effect of supraglottic and super-supraglottic swallows on tongue pressure production against hard palate.

    PubMed

    Fujiwara, Shigehiro; Ono, Takahiro; Minagi, Yoshitomo; Fujiu-Kurachi, Masako; Hori, Kazuhiro; Maeda, Yoshinobu; Boroumand, Sara; Nitschke, Ina; Ursula, Vith; Bohlender, Jörg

    2014-12-01

    The objectives of this study were to evaluate the state of tongue pressure production during supraglottic swallow (SS) and super-supraglottic swallow (SSS) performed by healthy adults, and to investigate the effects of these swallowing maneuvers on the oral stage of swallowing. The participants were 19 healthy individuals. Tongue pressure against the hard palate during swallowing was measured using a tongue pressure sensor sheet system with five pressure-sensitive points. The tasks comprised swallowing 5 mL of water by normal wet swallow, SS, and SSS, and the parameters for analysis were the duration, the maximal magnitude, and the integrated value of tongue pressure during swallowing. The duration of tongue pressure was significantly longer at the anterior-median part of the hard palate during both SS and SSS than with normal wet swallow. The maximal magnitude increased significantly only at the posterior part of the hard palate during SS, but at all points during SSS. The integrated value increased significantly only at the posterior-median part of the hard palate during SS, but at all points except the mid-median part of the hard palate during SSS. The maximal magnitude and integrated value were also significantly higher at the anterior-median and posterior circumferential parts during SSS than during SS. These results show that these two swallowing maneuvers, which are known primarily as techniques to protect the airway, also function to strengthen the tongue pressure produced by the contact between the tongue and the hard palate during swallowing and this effect is more pronounced during SSS. PMID:25055757

  1. The Value in Value Management: A Dialogue.

    ERIC Educational Resources Information Center

    Huish, John; van der Have, Pieter J.

    1998-01-01

    Details the value management process in which a group of diverse, disciplined professionals work together to design a better facility for a given budget. Areas addressed include a definition of value management, some derived benefits, negative aspects, projects best suited to this method, specific results, who pays, who is involved, scaled-down…

  2. Arsenic, nitrate, iron, and hardness in ground water, Chena Ridge vicinity, Fairbanks, Alaska

    USGS Publications Warehouse

    Krumhardt, Andrea P.

    1979-01-01

    The report presents all data on hardness, iron, nitrate and arsenic in well water in the Chena Ridge area of Fairbanks, Alaska, through June 1979. Concentrations range as follows: arsenic - 0 to 28 micrograms per liter; nitrate - 0 to 20 milligrams per liter; iron - 0 to 18 milligrams per liter and hardness - 72 to 1,400 milligrams per liter. Values at the upper ends of the ranges for iron and nitrate exceed limits recommended by the Environmental Protection Agency for public water supplies. A map of the area showing the location of sampled wells and a table of chemical analysis are included. (Kosco-USGS)

  3. Marcellus Author: "It's About Making Hard Choices in a Hard Land in Hard Times" Journalist and Pennsylvania native Seamus McGraw will share portraits of northeastern

    E-print Network

    Guiltinan, Mark

    Marcellus Author: "It's About Making Hard Choices in a Hard Land in Hard Times" Journalist the backdrop of Marcellus Shale development. Some environmentalists have decried what they see as the book at 1 p.m. This event is sponsored by the Penn State Marcellus Center for Outreach and Research

  4. Process for casting hard-faced, lightweight camshafts and other cylindrical products

    DOEpatents

    Hansen, Jeffrey S. (Corvallis, OR); Turner, Paul C. (Albany, OR); Argetsinger, Edward R. (Albany, OR); Wilson, Rick D. (Corvallis, OR)

    1996-01-01

    A process for casting a hard-faced cylindrical product such as an automobile camshaft includes the steps of: (a) preparing a composition formed from a molten base metal and an additive in particle form and having a hardness value greater than the hardness value of the base metal; (b) introducing the composition into a flask containing a meltable pattern of a cylindrical product such as an automobile camshaft to be manufactured and encased in sand to allow the composition to melt the pattern and assume the shape of the pattern within the sand; and (c) rotating the flask containing the pattern about the longitudinal axes of both the flask and the pattern as the molten base metal containing the additive in particle form is introduced into the flask to cause particles of the additive entrained in the molten base metal to migrate by centrifugal action to the radial extremities of the pattern and thereby provide a cylindrical product having a hardness value greater at it's radial extremities than at its center when the molten base metal solidifies.

  5. Correlation effects in multiple hard scattering

    E-print Network

    Markus Diehl

    2013-06-27

    Correlations between the incoming partons in multiple hard scattering can affect both the event rate and kinematic distributions in the final state. In this talk, I discuss different types of correlations relevant for double parton scattering in proton-proton collisions.

  6. Varietal Trials Results Wheat, Hard Red Winter

    E-print Network

    Thomas, David D.

    Varietal Trials Results Wheat, Hard Red Winter 47 Winter wheat varieties were compared in trial plots at Crookston, Lamberton, Roseau and St. Paul. Wheat varieties were grown in replicated plots. These winter wheat trials are not designed for crop (species) compar- isons because the various crops are grown

  7. Andersen Filtration and Hard Lefschetz Wolfgang Soergel

    E-print Network

    Soergel, Wolfgang

    Andersen Filtration and Hard Lefschetz Wolfgang Soergel July 5, 2007 For Joseph Bernstein Abstract we define a natural filtration following Andersen [And97] and establish a formula express- ing the dimensions of the filtration steps in terms of coefficients of Kazhdan-Lusztig polynomials. 1 Introduction

  8. Troubleshooting: NP-hardness and solution methods

    Microsoft Academic Search

    Marta Vomlelov; Jirí Vomlel

    2000-01-01

    Troubleshooting is one of the areas where Bayesian networks are successfully applied [9]. In this paper we show that the generally defined troubleshooting task is NP-hard. We propose a heuristic function that exploits the conditional independence of all actions and questions given the fault of the device. It can be used as a lower bound of the expected cost of

  9. Registration of ‘Sprinter’ hard red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High grain protein concentration and stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici Eriks.) resistance are important traits for hard red winter wheat (Triticum aestivum L.) cultivars produced in the Pacific Northwest region of the United States. The objective of this research wa...

  10. Vr de harde knip! KLAAS LANDSMAN

    E-print Network

    Landsman, N.P. "Klaas"

    Vóór de harde knip! KLAAS LANDSMAN In december werd mij in de pauze van een col- lege gevraagd om. Toen ik natuurkunde studeer- de,1 duurde de studie nominaal vijf jaar. De eerste 2.5 jaar werd werd dan ook als onvolwaardig gezien, een grotendeels zinloos tussenstation dat zeker niet bedoeld

  11. Hard and flexible optical printed circuit board

    NASA Astrophysics Data System (ADS)

    Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

    2007-02-01

    We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

  12. Thermal plasma deposition of nanophase hard coatings

    Microsoft Academic Search

    J. Heberlein; O. Postel; S. Girshick; P. McMurry; W. Gerberich; D. Iordanoglou; F. Di Fonzo; D. Neumann; A. Gidwani; M. Fan; N. Tymiak

    2001-01-01

    Thermal plasmas offer several specific advantages for the generation of hard coatings. In particular, the high energy density of the thermal plasma allows higher precursor flow rates and a wider choice of precursors. Expansion of the plasma into a low pressure chamber offers the additional advantages that improved control over the chemistry can be achieved or that nanosize particles can

  13. Help! Libraries and the Hard of Hearing.

    ERIC Educational Resources Information Center

    1982

    This transcript contains the text of three speeches on the problems of people with hearing impairments and the provision of library services to the hard of hearing. Howard Edward (Rocky) Stone, founder of Self-Help-For-Hearing-Impaired-People, Inc., describes his difficulties as a hearing impaired person, the growing number of Americans with…

  14. Approximation Algorithms for NP-Hard Problems

    Microsoft Academic Search

    1997-01-01

    Approximation algorithms have developed in response to the impossibility of solving a great variety of important optimization problems. Too frequently, when attempting to get a solution for a problem, one is confronted with the fact that the problem is NP-hard. This, in the words of Garey and Johnson, means \\

  15. Radiation-Hardness Data For Semiconductor Devices

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Nichols, D. K.; Brown, S. F.; Gauthier, M. K.; Martin, K. E.

    1984-01-01

    Document presents data on and analysis of radiation hardness of various semiconductor devices. Data specifies total-dose radiation tolerance of devices. Volume 1 of report covers diodes, bipolar transistors, field effect transistors, silicon controlled rectifiers and optical devices. Volume 2 covers integrated circuits. Volume 3 provides detailed analysis of data in volumes 1 and 2.

  16. On the hardness of approximating minimization problems

    Microsoft Academic Search

    Carsten Lund; Mihalis Yannakakis

    1993-01-01

    We prove results indicating that it is hard to compute efficiently good approximate solutions to the Graph Coloring, Set Covering and other related minimization problems. Specifi- cally, there is an E > 0 such that Graph Coloring cannot be approximated with ratio n' unless P = NP. Set Covering cannot be approximated with ratio c log n for any c

  17. Hard Times: Philosophy and the Fundamentalist Imagination

    ERIC Educational Resources Information Center

    Allsup, Randall Everett

    2005-01-01

    A close reading of Gradgrind's opening monologue of Hard Times by Charles Dickens will provide the starting off point for an examination of the role and place of philosophy in the music curriculum. The Gradgrind philosophy finds easy parallel to current thinking in American education. In the fundamentalist imagination, sources of ambiguity must be…

  18. When Are Children Hard to Understand?

    ERIC Educational Resources Information Center

    Fabian, Veronica

    Three empirical studies were conducted to investigate the hypothesis that the "easy to see" construction (such as in the sentence "children are hard to understand") is acquired at a younger age than the 7-9 year range reported by previous studies (Cambon and Sinclair, 1974; Chomsky, 1969; 1972; Cromer, 1970; Kessel, 1970). Four-year-olds were…

  19. DIELECTRIC SPECTROSCOPY OF HARD RED WINTER WHEAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dielectric properties (components of the complex permittivity relative to free space) of ground hard red winter wheat of 11 to 25 percent moisture content were determined by dielectric spectroscopy measurements with an open-ended coaxial-line probe and impedance analyzer over the frequency range...

  20. Most stable structure for hard spheres.

    PubMed

    Koch, Hans; Radin, Charles; Sadun, Lorenzo

    2005-07-01

    The hard sphere model is known to show a liquid-solid phase transition, with the solid expected to be either face centered cubic or hexagonal close packed. The differences in free energy of the two structures are very small and various attempts have been made to determine which structure is the more stable. We contrast the different approaches and extend one. PMID:16090135

  1. Cobalt in hard metal manufacturing dusts

    Microsoft Academic Search

    MATTI KOPONEN; TOM GUSTAFSSON; PIRKKO-LIISA KALLIOMÄKI

    1982-01-01

    Cobalt containing airborne dusts from hard metal manufacturing and grinding processes were analyzed by atomic absorption spectroscopy and instrumental neutron activation analysis. The structure of the dusts was studied using scanning electron microscopy with energy dispersive X-ray detector. Cobalt was found to exist as separate particles only in the dust from the mixing of raw material powders. In the dusts

  2. PROTEIN TEMPLATES IN HARD TISSUE ENGINEERING

    PubMed Central

    George, Anne; Ravindran, Sriram

    2010-01-01

    Biomineralization processes such as formation of bones and teeth require controlled mineral deposition and self-assembly into hierarchical biocomposites with unique mechanical properties. Ideal biomaterials for regeneration and repair of hard tissues must be biocompatible, possess micro and macroporosity for vascular invasion, provide surface chemistry and texture that facilitate cell attachment, proliferation, differentiation of lineage specific progenitor cells, and induce deposition of calcium phosphate mineral. To expect in-vivo like cellular response several investigators have used extracellular matrix proteins as templates to recreate in-vivo microenvironment for regeneration of hard tissues. Recently, several novel methods of designing tissue repair and restoration materials using bioinspired strategies are currently being formulated. Nanoscale structured materials can be fabricated via the spontaneous organization of self-assembling proteins to construct hierarchically organized nanomaterials. The advantage of such a method is that polypeptides can be specifically designed as building blocks incorporated with molecular recognition features and spatially distributed bioactive ligands that would provide a physiological environment for cells in-vitro and in-vivo. This is a rapidly evolving area and provides a promising platform for future development of nanostructured templates for hard tissue engineering. In this review we try to highlight the importance of proteins as templates for regeneration and repair of hard tissues as well as the potential of peptide based nanomaterials for regenerative therapies. PMID:20802848

  3. Integration of Hard Real-Time and

    E-print Network

    Ungerer, Theo

    Integration of Hard Real-Time and Organic Computing Florian Kluge,1 , Jörg Mische,1 , Stefan running a real-time application with organic computing features. This capability is exploited: Autonomic computing; organic computing; multithreading; real-time scheduling; mi- crokernel 1 Introduction

  4. Improved radiation hardness of silicon solar cells

    Microsoft Academic Search

    Hidetoshi Washio; Yoshifumi Tonomura; Minoru Kaneiwa; Tatsuo Saga; O. Anzawa; S. Matsuda

    2000-01-01

    SHARP and NASDA (National Space Development Agency of Japan) have been engaged in the development of silicon space solar cells since 1970s. We started the project to improve the radiation hardness of silicon solar cells in 1998. This project gave fruitful results in BJ (both-side junction) and AHES (advanced high efficiency silicon) structure. The design and manufacturing process for the

  5. Advances in sintering of hard metals

    Microsoft Academic Search

    A. Upadhyaya; D. Sarathy; G. Wagner

    2001-01-01

    Among the various advances in the processing of cemented carbides, this study emphasizes on the strategies to reduce the sintering time and improving the properties. It has been shown that the cycle time for consolidating metal cutting grades can be reduced by as much as 70% by employing a fast dewaxing-rapid sintering approach. For mining and metal-forming grade hard metals,

  6. Clinical Terminology: Why is it so hard?

    Microsoft Academic Search

    Alan L. Rector

    Abstract Despite years of work, no re-usable clinical terminology has yet been demonstrated in widespread use. This paper puts forward ten reasons why developing such terminologies is hard. All stem from underestimating the change entailed in using terminology in software for ‘patient centred’ systems rather than for its traditional functions of statistical and financial reporting. Firstly, the increase in scale

  7. BALLISTICS PERFORMANCE OF THE DUAL HARDNESS ARMOUR

    Microsoft Academic Search

    J. Buchar; J. Voldiich; S. Rolc; J. Lisy; J. Vold?ich

    3 This paper presents the results of the projectile penetration into layered targets. Targets consist of two steel layers. The front of the target is made from the steel of a higher hardness . The ballistic experiments are numerically simulated by the finite element code LS DYNA 3D. The influence of the thickness of steel layers have been tested. Instead

  8. DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION

    E-print Network

    DISTRIBUTED VERIFICATION AND HARDNESS OF DISTRIBUTED APPROXIMATION ATISH DAS SARMA, STEPHAN HOLZER Abstract. We study the verification problem in distributed networks, stated as follows. Let H be a subgraph in a decentralized fashion via a distributed algorithm. The time complexity of verification is measured as the number

  9. Distributed Verification and Hardness of Distributed Approximation

    E-print Network

    Distributed Verification and Hardness of Distributed Approximation Atish Das Sarma Google wattenhofer@tik.ee.ethz.ch ABSTRACT We study the verification problem in distributed networks, stated like to perform this verification in a decentralized fashion via a distributed algorithm. The time

  10. Hard and Easy Distributions of SAT Problems

    Microsoft Academic Search

    David G. Mitchell; Bart Selman; Hector J. Levesque

    1992-01-01

    We report results from large-scale experiments in satisfiabilitytesting. As has been observed by others, testingthe satisfiability of random formulas often appears surprisinglyeasy. Here we show that by using the rightdistribution of instances, and appropriate parametervalues, it is possible to generate random formulas thatare hard, that is, for which satisfiability testing is quitedifficult. Our results provide a benchmark for the evaluationof

  11. Classic Nintendo Games are (Computationally) Hard

    E-print Network

    Demaine, Erik

    game franchises: Mario, Donkey Kong, Legend of Zelda, Metroid, and Pok´emon. Our results apply­3; all Legend of Zelda games; all Metroid games; and all Pok´emon role-playing games. In addition, we, Legend of Zelda, Metroid, and Pok´emon. We prove that it is NP-hard, and in some cases PSPACE

  12. Where the Really Hard Problems Are

    Microsoft Academic Search

    Peter Cheeseman; Bob Kanefsky; William M. Taylor

    1991-01-01

    It is well known that for many NP-complete problems, such as K-Sat, etc., typical cases are easy to solve; so that computationally hard cases must be rare (assuming P = NP). This paper shows that NP-complete problems can be summarized by at least one \\

  13. Climate dynamics of a hard snowball Earth

    Microsoft Academic Search

    R. T. Pierrehumbert

    2005-01-01

    The problem of deglaciating a globally ice-covered (“hard snowball”) Earth is examined using a series of general circulation model simulations. The aim is to determine the amount of CO2 that must be accumulated in the atmosphere in order to trigger deglaciation. Prior treatments of this problem have been limited to energy balance models, which are incapable of treating certain crucial

  14. Hardness and softness in density functional theory

    Microsoft Academic Search

    José Gázquez

    The fundamental equations to describe the change from one ground-state to another, in the framework of density functional theory, are used to analyze a set of hardness and softness functions that are hierarchized as non-local, local and global quantities. Through these definitions it is shown that under conditions of constant chemical potential, the interaction between two chemical systems evolves towards

  15. Clinical findings among hard metal workers.

    PubMed Central

    Fischbein, A; Luo, J C; Solomon, S J; Horowitz, S; Hailoo, W; Miller, A

    1992-01-01

    In 1940, the first report appeared describing a pulmonary disorder associated with occupational exposures in the cemented tungsten carbide industry. The disease, known as "hard metal disease," has subsequently been characterised in detail and comprises a wide range of clinical signs and symptoms. In this report, clinical findings in a group of 41 hard metal workers employed until recently are described. A high prevalence of respiratory symptoms was found. Thirteen workers (31%) had abnormal chest radiographs indicative of interstitial lung disease. Fifty per cent of these had been employed in hard metal manufacturing for less than 10 years. Abnormalities of pulmonary function were also frequent and included a restrictive pattern of impairment and decrease in diffusing capacity (27%). Associations were found between diffusing capacity, chest radiographic abnormalities and right ventricular ejection fraction at exercise indicating cardiopulmonary effects. The findings show the continuous need to control excessive occupational exposures to prevent hard metal disease, the history of which now enters its sixth decade. PMID:1733452

  16. COMPUTATIONAL HARDNESS OF VALIDITY IN PROBABILITY LOGIC

    E-print Network

    Bosma, Wieb

    COMPUTATIONAL HARDNESS OF VALIDITY IN PROBABILITY LOGIC RUTGER KUYPER Abstract. We consider the complexity of validity in -logic, a probability logic introduced by Terwijn. We prove that the set of valid, there have been many attempts at combining logic and probability through so-called probability logics. We

  17. ‘SOFT’ VERSUS ‘HARD’ NEWS ON MICROBLOGGING NETWORKS

    Microsoft Academic Search

    Tyler J. Horan

    2012-01-01

    This article examines the variability of produsage (the hybridization of production and consumption) within popular social media by introducing semantic network analysis of information communication on Twitter. Utilizing user data (n[2,254,806]), the study examines the dynamics of produsage (a) as a function of user activity and (b) whether produsage levels vary based on either ‘soft’ or ‘hard’ news information. The

  18. Microfabricated electrostatic actuators for hard disk drives

    Microsoft Academic Search

    David A. Horsley; Roberto Horowitz; Albert P. Pisano

    1998-01-01

    A dual-stage servo system which utilizes a high-bandwidth secondary actuator has been proposed for magnetic hard disk drives. Microfabricated actuators are promising candidates for this secondary actuator, since they offer the benefits of extremely small size and weight and may be batch fabricated for reduced production cost. This paper presents the design of an electrostatic microactuator which produces sufficient output

  19. Future trends in hard disk drives

    Microsoft Academic Search

    Edward Grochowski; Roger F. Hoyt

    1996-01-01

    Magnetic hard disk drives have significantly improved in size, performance and cost due to many technological innovations; including magnetoresistive heads, low noise thin film disks, PRML channels and advanced mechanical actuators and motors. By analyzing specification trends of each new disk drive design, a perspective of this evolution can be developed and design characteristics of future disk drives can be

  20. Religion and Value Systems

    Microsoft Academic Search

    Sonia Roccas

    2005-01-01

    Uncovering the complex relationships between religiosity and values may provide a better understanding of what it means to be religious or nonreligious. This article reviews research on values and religiosity across cultural and religious groups. Although religious groups differ in the importance they attribute to different values, the pattern of correlations between religiosity and values is strikingly consistent across monotheistic

  1. Five Values of Giftedness

    ERIC Educational Resources Information Center

    Besjes-de Bock, Karin M.; de Ruyter, Doret J.

    2011-01-01

    This article describes five values attributed to giftedness. The ascription of values to this phenomenon resembles values attached to gifts in gift-giving processes. Whereas gift-giving often includes expectations of reciprocity, each gift possesses a numerical, utility, social, personal, and intrinsic value. Developmental models of giftedness and…

  2. Characterization of nano-wear mechanisms of hard disk coatings

    NASA Astrophysics Data System (ADS)

    Kim, Woo Seok; Kim, Jang-Kyo; Hwang, Pyung

    2001-05-01

    The wear mechanisms of carbon coated computer hard disks with laser-textured (LT) and mechanically-textured (MT) surfaces were characterized after contact start/stop (CSS) cyclic tests. Various analytical and mechanical testing techniques were employed to study the changes in topography, roughness, chemical elements, mechanical properties, and friction characteristics of the coating and lubricant. These techniques include: the atomic force microscopy (AFM), continuous nano-indentation test, nano-scratch test, time-of-flight secondary ion mass spectroscopy (TOF-SIMS), and Auger electron spectroscopy (AES). The CSS test at 15 k cycles resulted in tangible reductions of surface roughness of approximately 3.0 nm and 5.8 nm, respectively, for the LT bump and MT zone. The elastic modulus and hardness values increased after the CSS test, indicating strain hardening of the top coating layer. A critical load was identified for adhesion failure between the magnetic layer and the Ni-P layer. The TOF-SIMS analysis also revealed reductions in the intensities of all lubricant elements, indicating wear of the lubricant applied on the disk surface. All foregoing results confirm the usefulness of the characterization techniques employed to detect the subtle changes in disk surface characteristics.

  3. Deformation twinning in single-crystal monoclinic zirconia; A first report

    SciTech Connect

    First, R.C.; Aeuer, H. (Case Western Reserve Univ., Cleveland, OH (United States))

    1992-08-01

    In this paper, the hardness of single crystals of flux-grown, untwinned monoclinic zirconia is determined using Knoop and Vickers microindenters. Significant harness anisotropy existed on (100) and (110) faces, with a maximum Knoop hardness of [approximately] 8 GPa, although large variance was observed between different batches of crystals. Extensive deformation twining, primarily on (110), but also on (001), accompanied microindentation at all temperatures between room temperature and 800[degrees]C.

  4. Gruter Institute Project on Values and Free Enterprise

    E-print Network

    Richerson, Peter J.

    in the modern period as culturally transmitted values related to honesty, hard work, and education achievement of man. The American aborigines, Negroes, and Europeans are as different from each other in mind as any who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage

  5. The material co-construction of hard science fiction and physics

    NASA Astrophysics Data System (ADS)

    Hasse, Cathrine

    2014-02-01

    This article explores the relationship between hard science fiction and physics and a gendered culture of science. Empirical studies indicate that science fiction references might spur some students' interest in physics and help develop this interest throughout school, into a university education and even further later inspire the practice of doing science. There are many kinds of fiction within the science fiction genre. In the presented empirical exploration physics students seem particularly fond of what is called `hard science fiction': a particular type of science fiction dealing with technological developments (Hartwell and Cramer in The hard SF renaissance, Orb/TOR, New York, 2002). Especially hard science fiction as a motivating fantasy may, however, also come with a gender bias. The locally materialized techno-fantasies spurring dreams of the terraforming of planets like Mars and travels in time and space may not be shared by all physics students. Especially female students express a need for other concerns in science. The entanglement of physics with hard science fiction may thus help develop some students' interest in learning school physics and help create an interest for studying physics at university level. But research indicates that especially female students are not captured by the hard techno-fantasies to the same extent as some of their male colleagues. Other visions (e.g. inspired by soft science fiction) are not materialized as a resource in the local educational culture. It calls for an argument of how teaching science is also teaching cultural values, ethics and concerns, which may be gendered. Teaching materials, like the use of hard science fiction in education, may not just be (yet another) gender bias in science education but also carrier of particular visions for scientific endeavours.

  6. A mode-switching controller with initial value compensation for hard disk drive servo control

    Microsoft Academic Search

    T. Yamaguchi; K. Shishida; S. Tohyama; Y. Soyama; H. Hosokawa; H. Ohsawa; H. Numasato; T. Arai; K. Tsuneta; H. Hirai

    1997-01-01

    In various kinds of servo positioning systems, both fast movement and precise positioning are required. To meet these demands, a mode-switching control (MSC) method, which has several controllers for each requirement and switches from one to the other, has been proposed. The issue raised by the use of this technique is the transient response after switching. This paper proposes the

  7. Investigation of structural, dielectric, and magnetic properties of hard and soft mixed ferrite composites

    NASA Astrophysics Data System (ADS)

    Kotnala, R. K.; Ahmad, Shahab; Ahmed, Arham S.; Shah, Jyoti; Azam, Ameer

    2012-09-01

    Barium ferrite (hard ferrite) and manganese nickel zinc ferrite (soft ferrite) were successfully synthesized by citrate gel combustion technique. They were used to form the composites by mixing them properly in required compositions (x)BaFe12O19-(1-x)Mn0.2Ni0.4Zn0.4Fe2O4 (0 ? x ? 1). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to investigate the different structural and morphological parameters of pure and mixed ferrite composites. XRD and SEM results confirmed the coexistence of both phases in the composite material. Moreover, it has been observed that the composites were constituted by nanosized particles. Structure of pure soft ferrite was found to be cubic and that of pure hard ferrite was hexagonal. Dielectric constant (?' and ??) and dielectric loss (tan ?) were analyzed as a function of frequency and composition and the behaviour is explained on the basis of Maxwell-Wagner model. It was observed that the dielectric loss decreases with the increase of hard ferrite content in the composite material. Magnetic measurements suggest the exchange coupling between the magnetizations of soft and hard ferrite grains. It has been observed that the coercivity increases with the increase of the volume of the hard phase in the composite material after an optimal value.

  8. Exploring Existence Value

    NASA Astrophysics Data System (ADS)

    Madariaga, Bruce; McConnell, Kenneth E.

    1987-05-01

    The notion that individuals value the preservation of water resources independent of their own use of these resources is discussed. Issues in defining this value, termed "existence value," are explored. Economic models are employed to assess the role of existence value in benefit-cost analysis. The motives underlying existence value are shown to matter to contingent valuation measurement of existence benefits. A stylized contingent valuation experiment is used to study nonusers' attitudes regarding projects to improve water quality in the Chesapeake Bay. Survey results indicate that altruism is one of the motives underlying existence value and that goods other than environmental and natural resources may provide existence benefits.

  9. High-energy strong interactions: from `hard' to `soft'

    NASA Astrophysics Data System (ADS)

    Ryskin, M. G.; Martin, A. D.; Khoze, V. A.

    2011-04-01

    We discuss the qualitative features of the recent data on multiparticle production observed at the LHC. The tolerable agreement with Monte Carlos based on LO DGLAP evolution indicates that there is no qualitative difference between `hard' and `soft' interactions; and that a perturbative QCD approach may be extended into the soft domain. However, in order to describe the data, these Monte Carlos need an additional infrared cutoff k min with a value k min ˜2-3 GeV which is not small, and which increases with collider energy. Here we explain the physical origin of the large k min . Using an alternative model which matches the `soft' high-energy hadron interactions smoothly on to perturbative QCD at small x, we demonstrate that this effective cutoff k min is actually due to the strong absorption of low k t partons. The model embodies the main features of the BFKL approach, including the diffusion in transverse momenta, ln k t , and an intercept consistent with resummed next-to-leading log corrections. Moreover, the model uses a two-channel eikonal framework, and includes the contributions from the multi-Pomeron exchange diagrams, both non-enhanced and enhanced. The values of a small number of physically-motivated parameters are chosen to reproduce the available total, elastic and proton dissociation cross section (pre-LHC) data. Predictions are made for the LHC, and the relevance to ultra-high-energy cosmic rays is briefly discussed. The low x inclusive integrated gluon PDF, and the diffractive gluon PDF, are calculated in this framework, using the parameters which describe the high-energy pp and pbar{p} ` soft' data. Comparison with the PDFs obtained from the global parton analyses of deep inelastic and related hard scattering data and from diffractive deep inelastic data looks encouraging.

  10. Photovoltaics Value Analysis

    National Renewable Energy Laboratory (NREL)

    the United States. The high end of the range corresponds to the high values found in the literature search. Our perception is that this value corresponds to the 90 th percentile...

  11. Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm

    E-print Network

    Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm Annual Status Report 2003 #12;Hard Bottom Substrate Monitoring Horns Rev Offshore Wind Farm Annual Status Report 2003 Published: 14 May 2004

  12. Laser thermographic technologies for hard copy recording

    NASA Astrophysics Data System (ADS)

    Bessmel'tsev, Viktor P.; Baev, Sergej G.

    1995-04-01

    Methods of hard copies recording based on thermal interaction of the beam from CO2 or YAG lasers with various kinds of films on any substrates have been developed. The recording processes are single-step and require no additional development. Among them are: (1) Laser thermodestruction of thin mask layers or of a material surface on any kinds of substrates. (2) Laser thermochemical reactions of thermal decomposition of metal salts in solid state phase on a surface of various hygroscopic substrates. The laser recording devices using the methods, described above have been developed and are manufactured now; they allow one to record hard copies with a size of up to 27 X 31 inches, a resolution of 4000 dpi.

  13. Nuclear hardness assurance for aeronautical systems

    NASA Astrophysics Data System (ADS)

    Patrick, R. P.; Ferry, J. M.

    1980-10-01

    Nuclear hardness assurance for aircraft and airborne systems is considered from the point of view of an affordable research program's formulation and management prior to systems acquisitions. Among the threats to aircraft primary and secondary structures, flight crews, and electronics are: (1) blast overpressures of 1-3 psi for a 1 megaton blast, (2) blast-generated gusts of 75-100 ft/sec, (3) thermal emissions of 20-80 cal/sq cm, and (4) radiation effects such as neutron influence, gamma rate, total gamma dose, and electromagnetic pulse (EMP). The Hardness Assurance Documentation Program is introduced as a method by which hardened baseline systems meeting program requirements can be updated throughout the design and development process. Emphasis is placed on the unique vulnerability of electronic components to nuclear blast effects, above all the EMP generated by high-altitude detonations.

  14. Hardness/intensity correlations among BATSE bursts

    NASA Technical Reports Server (NTRS)

    Paciesas, William S.; Pendleton, Geoffrey N.; Kouveliotou, Chryssa; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.

    1992-01-01

    Conclusions about the nature of gamma-ray bursts derived from the size-frequency distribution may be altered if a significant correlation exists between burst intensity and spectral shape. Moreover, if gamma-ray bursts have a cosmological origin, such a correlation may be expected to result from the expansion of the universe. We have performed a rudimentary search of the BATSE bursts for hardness/intensity correlations. The range of spectral shapes was determined for each burst by computing the ratio of the intensity in the range 100-300 keV to that in 55-300 keV. We find weak evidence for the existence of a correlation, the strongest effect being present when comparing the maximum hardness ratio for each burst with its maximum rate.

  15. Review of hard scattering and jet analysis

    E-print Network

    Michael J. Tannenbaum

    2007-03-01

    A review of hard-scattering and jet analysis in p-p and heavy ion collisions at RHIC is presented in the context of earlier work at the CERN ISR in the 1970's which utilized inclusive single or pairs of hadrons to establish that high transverse momentum particles in p-p collisions are produced from states with two roughly back-to-back jets which are the result of scattering of constituents of the nucleons as described by Quantum Chromodynamics (QCD), which was developed during the course of those measurements. These techniques have been used extensively and further developed at RHIC since they are the only practical method to study hard-scattering and jet phenomena in Au+Au central collisions at RHIC energies.

  16. Place Value Rocks!

    NSDL National Science Digital Library

    Ms.Roberts

    2009-03-04

    Play these educational math games and test your knowledge of Place Value! Can you use Place Value Blocks to help you represent different digits? Test your ability to write out given numbers into sentences with Cookies! How sharp are your place value skills? Test your knowledge with Golfing with numbers!! Be the hero of the day as you practice place value skills in the Lifeguard game! Reveal the ...

  17. Radiation Hardness Assurance for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Day, John H. (Technical Monitor)

    2002-01-01

    The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section 5. Section 6 presents the organization of the hardness assurance within a project. Section 7 discusses emerging radiation hardness assurance issues.

  18. Troubleshooting: NP-hardness and solution methods

    Microsoft Academic Search

    Marta Vomlelová; Jirí Vomlel

    2003-01-01

    Troubleshooting is one of the areas where Bayesian networks are successfully applied [9]. In this paper we show that the\\u000a generally defined troubleshooting task is NP-hard. We propose a heuristic function that exploits the conditional independence\\u000a of all actions and questions given the fault of the device. It can be used as a lower bound of the expected cost of

  19. Checking robust nonsingularity is NP-hard

    Microsoft Academic Search

    Svatopluk Poljak; Ji?í Rohn

    1993-01-01

    We consider the following problem: givenk+1 square matrices with rational entries,A0,A1,...,Ak, decide ifA0+r1A1+···+rkAk is nonsingular for all possible choices of real numbersr1, ...,rk in the interval [0, 1]. We show that this question, which is closely related to the robust stability problem, is NP-hard. The proof relies on the new concept ofradius of nonsingularity of a square matrix and on

  20. Dynamic Hardness Tester and Cure Meter

    NASA Technical Reports Server (NTRS)

    Madigosky, Walter M.; Fiorito, Ralph B.

    1993-01-01

    The Shore hardness tester is used extensively throughout industry to determine the static modulus of materials. The new apparatus described here extends the capability of an indentor-type tester into the dynamic regime, and provides a measurement of the dynamic shear or Young's modulus and loss factor as a function of frequency. The instrument, model and data of typical rubber samples are given and compared to other dynamic measurements.

  1. Conformal Solution Theory: Hard-Sphere Mixtures

    Microsoft Academic Search

    Douglas Henderson; Peter J. Leonard

    1971-01-01

    Conformal solution theory is examined. It is suggested that most difficulties associated with previous applications of this theory arise from the use of concentration-independent reference fluids. For the particular case of a hard-sphere mixture, it is shown that if the reference fluid is chosen so as to make the first-order term in the theory vanish, good results are obtained.

  2. Rad-Hard/HI-REL FPGA

    NASA Technical Reports Server (NTRS)

    Wang, Jih-Jong; Cronquist, Brian E.; McGowan, John E.; Katz, Richard B.

    1997-01-01

    The goals for a radiation hardened (RAD-HARD) and high reliability (HI-REL) field programmable gate array (FPGA) are described. The first qualified manufacturer list (QML) radiation hardened RH1280 and RH1020 were developed. The total radiation dose and single event effects observed on the antifuse FPGA RH1280 are reported on. Tradeoffs and the limitations in the single event upset hardening are discussed.

  3. Radial distribution function for hard spheres

    Microsoft Academic Search

    S. Bravo Yuste; A. Santos

    1991-01-01

    The radial distribution function g(r) provided by the solution of the Percus-Yevick (PY) equation for hard spheres is rederived in terms of the simplest Padé approximant of a function defined in the Laplace space that is consistent with the following physical requirements: g(r) is continuous for r>1, the isothermal compressibility is finite, and the zeroth- and first-order coefficients in the

  4. Hard spheres on the gyroid surface

    PubMed Central

    Dotera, Tomonari; Kimoto, Masakiyo; Matsuzawa, Junichi

    2012-01-01

    We find that 48/64 hard spheres per unit cell on the gyroid minimal surface are entropically self-organized. Striking evidence is obtained in terms of the acceptance ratio of Monte Carlo moves and order parameters. The regular tessellations of the spheres can be viewed as hyperbolic tilings on the Poincaré disc with a negative Gaussian curvature, one of which is, equivalently, the arrangement of angels and devils in Escher's Circle Limit IV. PMID:24098841

  5. The Hard X-Ray Telescope Mission

    Microsoft Academic Search

    P. Gorenstein; K. Joensen; S. Romaine; D. Worrall; R. Cameron; M. Weisskopf; B. Ramsey; J. Bilbro; R. Kroeger; N. Gehrels; A. Parsons; R. Smither; F. Christensen; O. Citterio; P. von Ballmoos

    1995-01-01

    The Hard X-Ray Telescope (HXT) mission concept contains focusing telescopes that collectively, observe simultaneously from the ultraviolet to 100 keV and in several narrow bands extending to 1 MeV. In pointed observations HXT is expected to have an order of magnitude more sensitivity and much finer angular resolution in the 10 to 100 keV band than all current and currently

  6. Circle Packing for Origami Design Is Hard

    E-print Network

    Demaine, Erik D; Lang, Robert J

    2010-01-01

    We show that deciding whether a given set of circles can be packed into a rectangle, an equilateral triangle, or a unit square are NP-hard problems, settling the complexity of these natural packing problems. On the positive side, we show that any set of circles of total area 1 can be packed into a square of size 8/pi=2.546... These results are motivated by problems arising in the context of origami design.

  7. The approximability of NP-hard problems

    Microsoft Academic Search

    Sanjeev Arora

    1998-01-01

    IntroductionMany problems in combinatorial optimization areNP-hard (see [60]). This has forced researchers toexplore techniques for dealing with NP-completeness.Some have considered algorithms that solve "typical" or "average" instances instead of worst-case instances[86, 100]. In practice, however, identifying"typical" instances is not easy. Other researchershave tried to design approximation algorithms. Analgorithm achieves an approximation ratio # for amaximization problem if,...

  8. Dewetting of lubricants on hard disks

    Microsoft Academic Search

    Lei Xu; D. Frank Ogletree; Miquel Salmeron; Huan Tang; Jing Gui; Bruno Marchon

    2000-01-01

    The de-wetting process of Zdol-type lubricants on hard disks has been studied at the molecular scale with scanning polarization force microscopy (SPFM) and ellipsometry. It was found that de-wetting occurred over hours to days when the initial lubricant layer was thicker than one monolayer (~20 Å thick). De-wetting was found to take place in a layered fashion for Zdol-TX and

  9. Rheology of hydrodynamically interacting concentrated hard disks

    Microsoft Academic Search

    X. F. Yuan; R. C. Ball

    1994-01-01

    We have developed a novel Lagrangian–Eulerian numerical scheme to model the dynamics of dense hard-disk suspensions with many-body hydrodynamic interactions in an incompressible Newtonian solvent. A simple derivation of analytical solution of lubrication force between disks is given. Reasonable agreement of viscosity calculated by lattice–gas cellular automata and our method is obtained, despite the lack of Brownian forces in our

  10. Value and Vision.

    ERIC Educational Resources Information Center

    Rodger, Eleanor Jo

    2002-01-01

    Discusses the value of public libraries and what it means to be valuable. Topics include shrinking library budgets; why there is public money for libraries; how to tell whether a service, product, or institution creates public value; political and legal support; administrative and operational feasibility; and enhancing public value. (LRW)

  11. Valuing Farm Financial Information

    Microsoft Academic Search

    Dana M. Marcellino; Christine A. Wilson

    2006-01-01

    Despite the merits of good farm record keeping, little is known about the value farmers place on their farm financial records. This study uses a willingness-to-accept experimental second price auction to elicit such values from farmers. Results indicate farm records are extremely valuable and that some diversity in values is explained by the characteristics of the records and farmers. We

  12. Values and female entrepreneurship

    Microsoft Academic Search

    Katherine Terrell; Michael Troilo

    2010-01-01

    Purpose – The purpose of this paper is to research the extent to which different types of values influence a woman's decision to become an entrepreneur. Design\\/methodology\\/approach – The paper constructs a two-stage model to capture the entrepreneurial decision. In the first stage, life values affect the decision to enter the workforce. In the second stage, work values impact the

  13. The American Value System

    ERIC Educational Resources Information Center

    Nussel, E. J.

    1977-01-01

    The contradictory values in America (i.e., the "new morality" versus traditional morals) are examined along with the attendant ambiguity of the role in which the school is placed as transmitter of cultural values. The search for consensus in value contradictions is also discussed. (LBH)

  14. Fixing fair value accounting

    Microsoft Academic Search

    Peter J. Wallison

    2009-01-01

    The concept of fair value accounting was introduced in 1993 to make financial statements easier to compare and balance sheets more reflective of real values. This article discusses the true consequences of fair value accounting and its impact on the stability of financial institutions. By Peter J. Wallison, American Enterprise Institute

  15. Emergy and Nonmarket Value

    EPA Science Inventory

    The purpose of this study is to better understand the differences and similarities between emergy and nonmarket economic valuation, when both are applied to value the same policies or development alternatives. The emdollar value of a good or service often exceeds the market value...

  16. Education, Values, and Valuing in Cosmopolitan Perspective

    ERIC Educational Resources Information Center

    Hansen, David T.; Burdick-Shepherd, Stephanie; Cammarano, Cristina; Obelleiro, Gonzalo

    2009-01-01

    In this article we describe a cosmopolitan orientation toward the place of values in human life. We argue that a cosmopolitan outlook can assist people in engaging the challenges of being thrown together with others whose roots, traditions, and inheritances differ. We show that cosmopolitanism implies neither an elite nor an aloof posture toward…

  17. What's the Value in Value-Added?

    ERIC Educational Resources Information Center

    Duffrin, Elizabeth

    2011-01-01

    As the profession of teaching continues to get more attention given recent events, a growing number of school districts from New York to California are adopting "value-added" measures of teaching quality to award bonuses or even tenure. And two competitive federal grants are spurring them on. The Teacher Incentive Fund has awarded 95 grants since…

  18. ValuePro Stock Value Calculator

    NSDL National Science Digital Library

    This online calculator tabulates the baseline valuation for any publicly traded stock. Enter the stock's ticker symbol, and the program will value the stock. Users may also change any of the input for a stock and revalue it. The site contains a brief helpful guide to using online valuation and a thoughtful review of the product from Business Week.

  19. Hardcore distributions for somewhat hard problems Russell Impagliazzo \\Lambda

    E-print Network

    Wang, Deli

    Hard­core distributions for somewhat hard problems Russell Impagliazzo \\Lambda Computer Science that for any such problem there is a specific ``hard­core'' set of in­ puts which is at least a ffi fraction, and then the function f (x 1 ; :::x k ) = f(x 1 ) \\Phi f(x 2 ):: \\Phi f(x k ) is ffl + (1 \\Gamma 2ffi) k ­ hard­core

  20. Requirements specification of distributed hard real-time operating systems

    Microsoft Academic Search

    ManSang Chung; Heonshik Shin

    1991-01-01

    The authors present the requirements specification for distributed hard real-time operating systems used in time-critical, mission-oriented systems. For this purpose the relevant models for distributed hard real-time processing are established based on the general characteristics of distributed hard real-time systems. Following these models the requirements of a distributed hard real-time operating system are specified, and the major concerns in requirements

  1. Solving the Hard Problem of Bertrand's Paradox

    E-print Network

    Diederik Aerts; Massimiliano Sassoli de Bianchi

    2014-06-27

    Bertrand's paradox is a famous problem of probability theory, pointing to a possible inconsistency in Laplace's principle of insufficient reason. In this article we show that Bertrand's paradox contains two different problems: an "easy" problem and a "hard" problem. The easy problem can be solved by formulating Bertrand's question in sufficiently precise terms, so allowing for a non ambiguous modelization of the entity subjected to the randomization. We then show that once the easy problem is settled, also the hard problem becomes solvable, provided Laplace's principle of insufficient reason is applied not to the outcomes of the experiment, but to the different possible "ways of selecting" an interaction between the entity under investigation and that producing the randomization. This consists in evaluating a huge average over all possible "ways of selecting" an interaction, which we call a 'universal average'. Following a strategy similar to that used in the definition of the Wiener measure, we calculate such universal average and therefore solve the hard problem of Bertrand's paradox. The link between Bertrand's problem of probability theory and the measurement problem of quantum mechanics is also briefly discussed.

  2. Characterization of Radiation Hard Silicon Materials

    SciTech Connect

    Luukka, P.; Li, Z.; J. Harkonen, E. Tuovinen, S. Czellar, V. Eremin, E. Tuominen, E. Verbitskaya

    2009-02-24

    Segmented silicon detectors are widely used in modern high-energy physics (HEP) experiments due to their excellent spatial resolution and well-established manufacturing technology. However, in such experiments the detectors are exposed to high fluences of particle radiation, which causes irreversible crystallographic defects in the silicon material. Since 1990's, considerable amount of research has gone into improving the radiation hardness of silicon detectors. One very promising approach is to use magnetic Czochralski silicon (MCz-Si) that has been found to be more radiation hard against charged hadrons than traditional Float Zone silicon material (Fz-Si) used in the current HEP applications. Other approaches include operating the devices at cryogenic temperatures and designing special detector structures such as p-type detectors or semi-3D detectors. In order to demonstrate that the developed technologies are suitable for the HEP experiments, it is necessary to extensively characterize the potentially radiation hard detectors. We have an excellent instrument for this, the Cryogenic Transient Current Technique (C-TCT) measurement setup, which is an effective research tool for studying heavily irradiated silicon detectors. With the C-TCT setup it is possible to extract the full depletion voltage, effective trapping time, electric field distribution and the sign of the space charge in the silicon bulk in the temperature range of 45-300 K. This articles presents a description of this setup and measurement results from detectors processed of MCz-Si.

  3. Solving the hard problem of Bertrand's paradox

    SciTech Connect

    Aerts, Diederik, E-mail: diraerts@vub.ac.be [Center Leo Apostel for Interdisciplinary Studies and Department of Mathematics, Brussels Free University, Brussels (Belgium); Sassoli de Bianchi, Massimiliano, E-mail: autoricerca@gmail.com [Laboratorio di Autoricerca di Base, Lugano (Switzerland)

    2014-08-15

    Bertrand's paradox is a famous problem of probability theory, pointing to a possible inconsistency in Laplace's principle of insufficient reason. In this article, we show that Bertrand's paradox contains two different problems: an “easy” problem and a “hard” problem. The easy problem can be solved by formulating Bertrand's question in sufficiently precise terms, so allowing for a non-ambiguous modelization of the entity subjected to the randomization. We then show that once the easy problem is settled, also the hard problem becomes solvable, provided Laplace's principle of insufficient reason is applied not to the outcomes of the experiment, but to the different possible “ways of selecting” an interaction between the entity under investigation and that producing the randomization. This consists in evaluating a huge average over all possible “ways of selecting” an interaction, which we call a universal average. Following a strategy similar to that used in the definition of the Wiener measure, we calculate such universal average and therefore solve the hard problem of Bertrand's paradox. The link between Bertrand's problem of probability theory and the measurement problem of quantum mechanics is also briefly discussed.

  4. Hardness variability in commercial and hardened technologies

    SciTech Connect

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-03-01

    Over the past 10 years, there have been a number of advances in methods to assess and assure the radiation hardness of microelectronics in military and space applications. At the forefront of these is the Qualified Manufacturers List (QML) methodology, in which the hardness of product is ``built-in`` through statistical process control (SPC) of technology parameters relevant to the radiation response, test structure to integrated circuit (IC) correlations, and techniques for extrapolating laboratory test results to varying radiation scenarios. At the same time, there has been renewed interest in the use of commercial technology -- with its enhanced performance, reduced cost, and higher reliability -- in military and space systems. In this paper, we initially demonstrate the application of QML techniques to assure and control the radiation response of hardened technologies. Through several examples, we demonstrate intra-die, wafer-to-wafer, and lot-to-lot variations in a hardened technology. We observe 10 to 30% variations in key technology parameters that result from variability in geometry, process, and design layout. Radiation-induced degradation is seen to mirror preirradiation characteristics. We then evaluate commercial technologies and report considerably higher variability in radiation hardness, i.e., variations by a factor of two to five. This variability is shown to arise from a lack of control of technology parameters relevant to the radiation response, which a commercial manufacturer has no interest in controlling in a normal process flow.

  5. The hard pulse approximation for the AKNS 2 2-system

    E-print Network

    scattering transform for this hard pulse approximation converge to the expected continuum potential pointwiseThe hard pulse approximation for the AKNS 2 Ã? 2-system Charles L. Epstein and Jeremy Magland LSNI, 2005 Abstract In the hard pulse approximation, commonly used in nuclear magnetic reso- nance, one

  6. Advanced Tool Edge Geometry for High Precision Hard Turning

    Microsoft Academic Search

    F. Klocke; H. Kratz

    2005-01-01

    The hard turning process has been attracting interest in different industrial sectors for finishing operations of hard materials. However, it still presents disadvantages with respect to process capability and reliability. In this paper the impact of PcBN tool edge geometry is investigated based on a modelling as well as an experimental approach. The hard turning process is described by means

  7. CMOS Hardness Assurance through Process Controls and Optimized Design Procedures

    Microsoft Academic Search

    T. J. Sanders

    1977-01-01

    Total Dose Hardness Assurance for complimentary MOS integrated circuits is recognized throughout the industry as a difficult problem. Most of the hardness assurance proposals to date have included a large amount of radiation testing on a diffision lot or wafer basis to help guarantee the hardness of a small group of integrated circuits. This, in general, is very expensive, and

  8. Climate dynamics of a hard snowball Earth R. T. Pierrehumbert

    E-print Network

    Pierrehumbert, Raymond

    Climate dynamics of a hard snowball Earth R. T. Pierrehumbert Department of Geophysical Sciences November 2004; published 15 January 2005. [1] The problem of deglaciating a globally ice-covered (``hard with codes explicitly designed for high CO2. In contrast to prevailing expectations, the hard snowball Earth

  9. THE ABUNDANCE AND DISTRIBUTION OF HARD CLAMS IN

    E-print Network

    THE ABUNDANCE AND DISTRIBUTION OF HARD CLAMS IN NANTUCKET SOUND, MASSACHUSETTS 1958 Marine AND DISTRIBUTION OF HARD CLAMS IN NANTUCKET SOUND, MASSACHUSETTS, 1958 by John W. Ropes Fishery Research Biologist Shoal -Great Point area 6 Edgartown area 7 Other areas sampled . . > 8 Sizes of hard clamiS caught 8

  10. The Hard Problem of Cooperation Kimmo Eriksson1,2

    E-print Network

    The Hard Problem of Cooperation Kimmo Eriksson1,2 *, Pontus Strimling1 1 Centre for the Study inclinations, we define the ``hard problem of cooperation'' as that of achieving high levels of cooperation in a group of non-cooperative types. Can the hard problem be solved by institutions with monitoring

  11. Study of hot hardness characteristics of tool steels

    NASA Technical Reports Server (NTRS)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1972-01-01

    Hardness measurements of tool steel materials in electric furnace at elevated temperatures and low oxygen environment are discussed. Development of equation to predict short term hardness as function of intial room temperature hardness of steel is reported. Types of steel involved in the process are identified.

  12. Aperiodic Task Scheduling for Hard Real-Time Systems

    Microsoft Academic Search

    Brinkley Sprunt; Lui Sha; John P. Lehoczky

    1989-01-01

     A real-time system consists of both aperiodic and periodic tasks. Periodic tasks have regular arrival times and hard deadlines. Aperiodic tasks have irregular arrival times and either soft or hard deadlines. In this article, we present a new algorithm, the Sporadic Server algorithm, which greatly improves response times for soft deadline aperiodic tasks and can guarantee hard deadlines for both

  13. Lining of light metals with hard powders using shot peening

    Microsoft Academic Search

    Yasunori Harada; Ken-ichiro Mori; Seijiro Maki

    2002-01-01

    A lining of light metals with hard powders using shot peening was carried out. The hard powders are bonded to the surface of the workpieces due to the collision with many shots. To fix the hard powders on the surface of the workpiece, the powder is placed on the uneven surface, and the surface is covered with a pure aluminium

  14. Vibrational Raman characterization of hard-carbon and diamond films

    Microsoft Academic Search

    Joel W. Ager; D. K. Veirs; Bruno Marchon; Namhee Cho; Gerd M. Rosenblatt

    1991-01-01

    Amorphous 'hard carbon' and microcrystalline diamond films are being investigated and characterized using high-sensitivity and spatial-profiling Raman spectroscopy. The 'hard carbon' films have broad Raman spectra with no diamond line while higher quality diamond films show only a single sharp diamond line. Features in the Raman spectra of the amorphous 'hard carbon' films correlate with the rates of specific types

  15. Hard Real-Time Programming is Different Peter Puschner

    E-print Network

    Hard Real-Time Programming is Different £ Peter Puschner Institut f¨ur Technische Informatik requirements imposed on (hard) real- time code resp. non real-time code differ. As a consequence, conventional coding strategies as used to develop non real- time software are not suited for hard real-time code

  16. Automatic Generation of Behavioral Hard Disk Drive Access Time Models

    E-print Network

    Maltzahn, Carlos

    Automatic Generation of Behavioral Hard Disk Drive Access Time Models Adam Crume, Carlos Maltzahn is a crucial part of pre- dicting hard disk drive performance. Existing approaches use white-box modeling assumptions, and less time. While previous research has created black-box models of hard disk drive

  17. Fault-Tolerant, Radiation-Hard DSP

    NASA Technical Reports Server (NTRS)

    Czajkowski, David

    2011-01-01

    Commercial digital signal processors (DSPs) for use in high-speed satellite computers are challenged by the damaging effects of space radiation, mainly single event upsets (SEUs) and single event functional interrupts (SEFIs). Innovations have been developed for mitigating the effects of SEUs and SEFIs, enabling the use of very-highspeed commercial DSPs with improved SEU tolerances. Time-triple modular redundancy (TTMR) is a method of applying traditional triple modular redundancy on a single processor, exploiting the VLIW (very long instruction word) class of parallel processors. TTMR improves SEU rates substantially. SEFIs are solved by a SEFI-hardened core circuit, external to the microprocessor. It monitors the health of the processor, and if a SEFI occurs, forces the processor to return to performance through a series of escalating events. TTMR and hardened-core solutions were developed for both DSPs and reconfigurable field-programmable gate arrays (FPGAs). This includes advancement of TTMR algorithms for DSPs and reconfigurable FPGAs, plus a rad-hard, hardened-core integrated circuit that services both the DSP and FPGA. Additionally, a combined DSP and FPGA board architecture was fully developed into a rad-hard engineering product. This technology enables use of commercial off-the-shelf (COTS) DSPs in computers for satellite and other space applications, allowing rapid deployment at a much lower cost. Traditional rad-hard space computers are very expensive and typically have long lead times. These computers are either based on traditional rad-hard processors, which have extremely low computational performance, or triple modular redundant (TMR) FPGA arrays, which suffer from power and complexity issues. Even more frustrating is that the TMR arrays of FPGAs require a fixed, external rad-hard voting element, thereby causing them to lose much of their reconfiguration capability and in some cases significant speed reduction. The benefits of COTS high-performance signal processing include significant increase in onboard science data processing, enabling orders of magnitude reduction in required communication bandwidth for science data return, orders of magnitude improvement in onboard mission planning and critical decision making, and the ability to rapidly respond to changing mission environments, thus enabling opportunistic science and orders of magnitude reduction in the cost of mission operations through reduction of required staff. Additional benefits of COTS-based, high-performance signal processing include the ability to leverage considerable commercial and academic investments in advanced computing tools, techniques, and infra structure, and the familiarity of the science and IT community with these computing environments.

  18. Development of method for evaluating cell hardness and correlation between bacterial spore hardness and durability

    PubMed Central

    2012-01-01

    Background Despite the availability of conventional devices for making single-cell manipulations, determining the hardness of a single cell remains difficult. Here, we consider the cell to be a linear elastic body and apply Young’s modulus (modulus of elasticity), which is defined as the ratio of the repulsive force (stress) in response to the applied strain. In this new method, a scanning probe microscope (SPM) is operated with a cantilever in the “contact-and-push” mode, and the cantilever is applied to the cell surface over a set distance (applied strain). Results We determined the hardness of the following bacterial cells: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and five Bacillus spp. In log phase, these strains had a similar Young’s modulus, but Bacillus spp. spores were significantly harder than the corresponding vegetative cells. There was a positive, linear correlation between the hardness of bacterial spores and heat or ultraviolet (UV) resistance. Conclusions Using this technique, the hardness of a single vegetative bacterial cell or spore could be determined based on Young’s modulus. As an application of this technique, we demonstrated that the hardness of individual bacterial spores was directly proportional to heat and UV resistance, which are the conventional measures of physical durability. This technique allows the rapid and direct determination of spore durability and provides a valuable and innovative method for the evaluation of physical properties in the field of microbiology. PMID:22676476

  19. 4-channel rad-hard delay generation ASIC with 1ns timing resolution for LHC

    SciTech Connect

    Toifl, T.; Moreira, P.; Marchioro, A. [CERN, Geneva (Switzerland)] [CERN, Geneva (Switzerland); Vari, R. [INFN Roma, Rome (Italy)] [INFN Roma, Rome (Italy)

    1999-06-01

    An ASIC was developed to precisely delay digital signals within the range of 0--24ns in steps of 1ns. To obtain well defined delay values independent of variations in process, supply voltage and temperature, four independent delay channels are controlled by a common control voltage derived from a delay-locked loop (DLL), which is synchronized to an external 40 MHz clock signal. The delay values of the four signal channels and the clock channel can be individually programmed via an I{sup 2}C interface. Due to an automatic reset logic the chip does not need an external reset signal. A first version of the chip was developed in a non-rad-hard 0.8 {micro}m technology and the successful prototype was then transferred to a radiation hard process (DMILL). Measurement results for both chip variants will be presented.

  20. The problem with value

    PubMed Central

    O’Doherty, John P.

    2015-01-01

    Neural correlates of value have been extensively reported in a diverse set of brain regions. However, in many cases it is difficult to determine whether a particular neural response pattern corresponds to a value-signal per se as opposed to an array of alternative non-value related processes, such as outcome-identity coding, informational coding, encoding of autonomic and skeletomotor consequences, alongside previously described “salience” or “attentional” effects. Here, I review a number of experimental manipulations that can be used to test for value, and I identify the challenges in ascertaining whether a particular neural response is or is not a value signal. Finally, I emphasize that some non-value related signals may be especially informative as a means of providing insight into the nature of the decision-making related computations that are being implemented in a particular brain region. PMID:24726573

  1. Place Value Frenzy

    NSDL National Science Digital Library

    Miss Carter

    2006-11-04

    Today, we are going to practice place value. Please read all directions below. Play Find the Place Value 1 time. Leave, name to appear on title, Blank. Leave, minimum number, on 1 . Put the maximum number on 1000. Then, click on generate to start game. Play Place Value 2 times. When the webpage comes up click on countdown to play the game. Play Frog Palace 1 time. Please ...

  2. Role of Surface Texture, Roughness, and Hardness on Friction During Unidirectional Sliding

    Microsoft Academic Search

    Pradeep L. MenezesKishoreSatish; Kishore; Satish V. Kailas; Michael R. Lovell

    2011-01-01

    In the present investigation, experiments were conducted by unidirectional sliding of pins made of FCC metals (Pb, Al, and\\u000a Cu) with significantly different hardness values against the steel plates of various surface textures and roughness using\\u000a an inclined pin-on-plate sliding apparatus in ambient conditions under both the dry and lubricated conditions. For a given\\u000a material pair, it was observed that

  3. Influence of pencil lead hardness on voltammetric response of graphite reinforcement carbon electrodes

    Microsoft Academic Search

    Paulo Henrique Campos Prado Tavares; Paulo Jorge Sanches Barbeira

    2008-01-01

    This work studied the voltammetric response of graphite reinforcement electrodes made of different pencil lead hardness. The\\u000a studies showed that harder graphite leads, regardless of their manufacturer, are more appropriate as electrode material for\\u000a voltammetric purposes due to their higher peak currents, increasing sensitivity and reproducibility, with ?Ep closer to the theoretical value for a reversible system.

  4. Hard-sphere-like dynamics in a non-hard-sphere liquid.

    PubMed

    Scopigno, T; Di Leonardo, R; Comez, L; Baron, A Q R; Fioretto, D; Ruocco, G

    2005-04-22

    The collective dynamics of liquid gallium close to the melting point has been studied using inelastic x-ray scattering to probe length scales smaller than the size of the first coordination shell. Although the structural properties of this partially covalent liquid strongly deviate from a simple hard-sphere model, the dynamics, as reflected in the quasielastic scattering, are beautifully described within the framework of the extended heat mode approximation of Enskog's kinetic theory, analytically derived for a hard-sphere system. The present work demonstrates, therefore, the applicability of Enskog's theory beyond simple liquids. PMID:15904154

  5. Comparison Between Neck and Shoulder Stiffness Determined by Shear Wave Ultrasound Elastography and a Muscle Hardness Meter.

    PubMed

    Akagi, Ryota; Kusama, Saki

    2015-08-01

    The goals of this study were to compare neck and shoulder stiffness values determined by shear wave ultrasound elastography with those obtained with a muscle hardness meter and to verify the correspondence between objective and subjective stiffness in the neck and shoulder. Twenty-four young men and women participated in the study. Their neck and shoulder stiffness was determined at six sites. Before the start of the measurements, patients rated their present subjective symptoms of neck and shoulder stiffness on a 6-point verbal scale. At all measurement sites, the correlation coefficients between the values of muscle hardness indices determined by the muscle hardness meter and shear wave ultrasound elastography were not significant. Furthermore, individuals' subjective neck and shoulder stiffness did not correspond to their objective symptoms. These results suggest that the use of shear wave ultrasound elastography is essential to more precisely assess neck and shoulder stiffness. PMID:25944285

  6. Tetraphosphonated thiophene ligand: mixing the soft and the hard.

    PubMed

    Brandel, Jérémy; Lecointre, Alexandre; Kollek, Julien; Michel, Sylvia; Hubscher-Bruder, Véronique; Déchamps-Olivier, Isabelle; Platas-Iglesias, Carlos; Charbonnière, Loïc J

    2014-06-28

    The synthesis of ligand L(T)H8, based on a thiophene framework containing two bis(aminomethyldiphosphonate) functions in the ortho position to the central sulfur atom, is described, together with the characterization of the intermediate compounds. The physico-chemical properties of the ligand were first studied by means of potentiometry and UV-Vis absorption spectrophotometric titrations to determine its pK values. Six successive equilibrium constants were determined in aqueous solutions. The same means were then used to quantify the interactions of the ligand with Ni(II), Cu(II) and Zn(II). Following the conventional Irving-Williams trend, L(T) was shown to have the highest affinity towards Cu(II) (log K(CuL(T)) = 16.11(3)), while Zn(II) and Ni(II) showed similar values (log K(ML(T)) = 10.81(8) and 10.9(1), respectively), revealing a large selectivity of L(T) toward Cu(II). Based on a combination of UV-Vis absorption spectroscopy and EPR measurements as a function of pH, along with DFT calculations, the coordination behavior of the hard phosphonate, medium amino and soft thiophene entities are questioned regarding their coordination to the Cu atom. PMID:24788186

  7. Ultrafast switching of hard X-rays.

    PubMed

    Gaal, Peter; Schick, Daniel; Herzog, Marc; Bojahr, André; Shayduk, Roman; Goldshteyn, Jevgeni; Leitenberger, Wolfram; Vrejoiu, Ionela; Khakhulin, Dmitry; Wulff, Michael; Bargheer, Matias

    2014-03-01

    A new concept for shortening hard X-ray pulses emitted from a third-generation synchrotron source down to few picoseconds is presented. The device, called the PicoSwitch, exploits the dynamics of coherent acoustic phonons in a photo-excited thin film. A characterization of the structure demonstrates switching times of ??5?ps and a peak reflectivity of ?10(-3). The device is tested in a real synchrotron-based pump-probe experiment and reveals features of coherent phonon propagation in a second thin film sample, thus demonstrating the potential to significantly improve the temporal resolution at existing synchrotron facilities. PMID:24562559

  8. The bounce hardness index of gravitational waves

    E-print Network

    Fumihiko Ishiyama; Ryutaro Takahashi

    2010-12-06

    We present a method of mode analysis to search for signals with frequency evolution and limited duration in a given data stream. Our method is a natural expansion of the Fourier analysis, and we can obtain the information about frequency evolution with high frequency precision and high time resolution. Applications of this method to the analysis of inspiral and burst signals show that the signals are characterized by an index which we name `bounce hardness'. The index corresponds to the growth rate of the signals.

  9. Hard Exclusive ?^0-Meson Production at COMPASS

    E-print Network

    H. Wollny for the COMPASS collaboration

    2012-05-30

    New results for the transverse target spin azimuthal asymmetry A_{UT}^{sin(\\phi-\\phi_S)} for hard exclusive \\rho^0-meson production on a transversely polarised ^6LiD and NH_3 target will be presented. The measurement was performed with the COMPASS detector using the 160 GeV/c muon beam of the SPS at CERN. The asymmetry is sensitive to the nucleon helicity-flip generalised parton distribution E, which is related to the orbital angular momentum of quarks in the nucleon.

  10. Multiple Glasses in Asymmetric Binary Hard Spheres

    E-print Network

    Th. Voigtmann

    2010-10-03

    Multiple distinct glass states occur in binary hard-sphere mixtures with constituents of very disparate sizes according to the mode-coupling theory of the glass transition (MCT), distinguished by considering whether small particles remain mobile or not, and whether small particles contribute significantly to perturb the big-particle structure or not. In the idealized glass, the four different glasses are separated by sharp transitions that give rise to higher-order transition phenomena involving logarithmic decay laws, and to anomalous power-law-like diffusion. The phenomena are argued to be expected generally in glass-forming mixtures.

  11. Hard Real-Time Networking on Firewire

    Microsoft Academic Search

    Yuchen Zhang; Bojan Orlic; Peter Visser; Jan Broenink; P Marquet; N McGuire; P Wurmsdobler

    2005-01-01

    This paper investigates the possibility of using standard, low-cost, widely used FireWire as a new generation fieldbus medium for real-time distributed control applications. A real-time software subsystem, RT-FireWire was designed that can, in combination with Linux-based real-time operating system, provide hard real-time communication over FireWire. In addition, a high-level module that can emulate Ethernet over RT-FireWire was implemented. This additional

  12. Evolutionary Algorithms for Hard Quantum Control

    E-print Network

    Ehsan Zahedinejad; Sophie Schirmer; Barry C. Sanders

    2014-09-15

    Although quantum control typically relies on greedy (local) optimization, traps (irregular critical points) in the control landscape can make optimization hard by foiling local search strategies. We demonstrate the failure of greedy algorithms to realize two fast quantum computing gates: a qutrit phase gate and a controlled-not gate. Then we show that our evolutionary algorithm circumvents the trap to deliver effective quantum control in both instances. Even when greedy algorithms succeed, our evolutionary algorithm delivers a superior control procedure because less time resolution is required for the control sequence.

  13. Classic Nintendo Games are (NP-)Hard

    E-print Network

    Aloupis, Greg; Guo, Alan

    2012-01-01

    We prove NP-hardness results for five of Nintendo's largest video game franchises: Mario, Donkey Kong, Legend of Zelda, Metroid, and Pokemon. Our results apply to Super Mario Bros. 1, 3, Lost Levels, and Super Mario World; Donkey Kong Country 1-3; all Legend of Zelda games except Zelda II: The Adventure of Link; all Metroid games; and all Pokemon role-playing games. For Mario and Donkey Kong, we show NP-completeness. In addition, we observe that several games in the Zelda series are PSPACE-complete.

  14. Nonvolatile Rad-Hard Holographic Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Zhou, Han-Ying; Reyes, George; Dragoi, Danut; Hanna, Jay

    2001-01-01

    We are investigating a nonvolatile radiation-hardened (rad-hard) holographic memory technology. Recently, a compact holographic data storage (CHDS) breadboard utilizing an innovative electro-optic scanner has been built and demonstrated for high-speed holographic data storage and retrieval. The successful integration of this holographic memory breadboard has paved the way for follow-on radiation resistance test of the photorefractive (PR) crystal, Fe:LiNbO3. We have also started the investigation of using two-photon PR crystals that are doubly doped with atoms of iron group (Ti, Cr, Mn, Cu) and of rare-earth group (Nd, Tb) for nonvolatile holographic recordings.

  15. Implementing QML (Qualified Manufacturers List) for radiation hardness assurance

    SciTech Connect

    Winokur, P.S.; Sexton, F.W.; Fleetwood, D.M.; Terry, M.D.; Shaneyfelt, M.R.; Dressendorfer, P.V.; Schwank, J.R.

    1990-01-01

    Statistical process control (SPC) of technology parameters relevant to radiation hardness, test structure to Integrated Circuit (IC) correlation, and extrapolation from laboratory to threat scenarios are keys to implementing Qualified Manufacture's List (QML) for radiation hardness assurance in a cost-effective manner. Data from approximately 300 wafer lots fabricated in Sandia's 4/3-{mu}m and Complementry Metal Oxide Semiconductor (CMOS) IIIA (2-{mu}m) technologies are used to demonstrate approaches to, and highlight issues associated with, implementing QML for radiation-hardened CMOS in space applications. An approach is demonstrated to implement QML for signal-event upset SEU immunity on 16k SRAMs that involves relating values of feedback resistance to system error rates. It is seen that the process capability indices, C{sub p} and C{sub pk}, for the manufacture of 400 k{Omega} feedback resistors required to provide SEU tolerance do not conform to 6{sigma}'' quality standards. For total-dose, {triangle}V{sub it} shifts measured on transistors are correlated with circuit response in the space environment. SPC is illustrated for {triangle}V{sub it}, and violations of SPC rules are interpreted in terms of continuous improvement. Finally, design validation for SEU, and quality conformance inspections for total-dose, are identified as major obstacles to cost-effective QML implementation. Techniques and tools that will help QML provide real cost savings are identified as physical models, three-dimensional device-plus-circuit codes, and improved design simulators. 29 refs., 10 figs., 1 tab.

  16. Dynamical localization in a chain of hard core bosons under periodic driving

    NASA Astrophysics Data System (ADS)

    Nag, Tanay; Roy, Sthitadhi; Dutta, Amit; Sen, Diptiman

    2014-04-01

    We study the dynamics of a one-dimensional lattice model of hard core bosons which is initially in a superfluid phase with a current being induced by applying a twist at the boundary. Subsequently, the twist is removed, and the system is subjected to periodic ?-function kicks in the staggered on-site potential. We present analytical expressions for the current and work done in the limit of an infinite number of kicks. Using these, we show that the current (work done) exhibits a number of dips (peaks) as a function of the driving frequency and eventually saturates to zero (a finite value) in the limit of large frequency. The vanishing of the current (and the saturation of the work done) can be attributed to a dynamic localization of the hard core bosons occurring as a consequence of the periodic driving. Remarkably, we show that for some specific values of the driving amplitude, the localization occurs for any value of the driving frequency. Moreover, starting from a half-filled lattice of hard core bosons with the particles localized in the central region, we show that the spreading of the particles occurs in a light-cone-like region with a group velocity that vanishes when the system is dynamically localized.

  17. Selected Papers on Values.

    ERIC Educational Resources Information Center

    Blackmon, C. Robert, Ed.

    This document contains papers and reports read at the August 1968, meeting of the Continuing Interest Group on Values, a subgroup of the National Conference of Professors of Educational Administration, held at the State University of New York at Albany. Included are three papers by C. Robert Blackmon; the first considers values as education's most…

  18. Values Clarification Through Writing.

    ERIC Educational Resources Information Center

    Strugala, Richard A.

    1982-01-01

    An approach to using values clarification exercises in a college freshman composition or a high school English class is presented in this brief article. AUTHOR'S COMMENT (excerpt): Since the integration of writing and thinking is vital in the development of writing abilities, the values clarification experience is a natural bridge for students to…

  19. Currency Value Game

    NSDL National Science Digital Library

    Brian Petro

    2004-09-28

    With this interactive game students practice identifying names and values of US currency. It provides a picture of one of the U.S. coins or the dollar bill, and a question prompt, both printed and voiced, that asks the value. Sound clips reward correct responses or encourage another try. The game comprises a five question set.

  20. High coking value pitch

    SciTech Connect

    Miller, Douglas J.; Chang, Ching-Feng; Lewis, Irwin C.; Lewis, Richard T.

    2014-06-10

    A high coking value pitch prepared from coal tar distillate and has a low softening point and a high carbon value while containing substantially no quinoline insolubles is disclosed. The pitch can be used as an impregnant or binder for producing carbon and graphite articles.

  1. Decimal Place Value

    NSDL National Science Digital Library

    Teacher Vision

    2012-08-02

    Students learn about decimal place value and the relationship between tenths, hundredths, and thousandths. Students will explore decimal place value, read and write decimals using tenths, hundredths, and thousandths, and compare decimals using greater-than and less-than notation.

  2. Understanding Place Value

    ERIC Educational Resources Information Center

    Cooper, Linda L.; Tomayko, Ming C.

    2011-01-01

    Developing an understanding of place value and the base-ten number system is considered a fundamental goal of the early primary grades. For years, teachers have anecdotally reported that students struggle with place-value concepts. Among the common errors cited are misreading such numbers as 26 and 62 by seeing them as identical in meaning,…

  3. Fair Value Accounting

    Microsoft Academic Search

    Tan Hock Neo Pearl

    2004-01-01

    The presentation examines the shifting landscape of financial reporting and the long-term implications of the introduction of new requirements for accountants to incorporate fair value information in financial statements and to assess fair value amounts of reported assets and liabilities.

  4. More Place Value Activities

    NSDL National Science Digital Library

    Terry Kawas

    2010-01-01

    This webpage contains instructions for several activities and games designed to develop students' understanding of place value while reinforcing addition and subtraction skills. Downloadable materials and suggestions for variations are included along with links to online games. This is the second of two pages of similar activities. The first, Place Value Activities, is catalogued separately.

  5. Rosenak "Teaching Jewish Values"

    ERIC Educational Resources Information Center

    Resnick, David

    2014-01-01

    Rosenak's "Teaching Jewish Values" (1986) is perhaps his most accessible book about Jewish education. After diagnosing the "diseases" of Jewish education, he endorses "teaching Jewish values" as the curricular strategy most likely to succeed given the chasm which divides traditional Jewish subject matter and the…

  6. Weak Value Theory

    SciTech Connect

    Shikano, Yutaka [Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551 (Japan) and Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2011-03-28

    I show that the weak value theory is useful from the viewpoints of the experimentally verifiability, consistency, capacity for explanation as to many quantum paradoxes, and practical advantages. As an example, the initial state in the Hardy paradox can be experimentally verified using the weak value via the weak measurement.

  7. Ultrasonically bonded value assembly

    NASA Technical Reports Server (NTRS)

    Salvinski, R. J. (inventor)

    1975-01-01

    A valve apparatus capable of maintaining a fluid-tight seal over a relatively long period of time by releasably bonding a valve member to its seat is described. The valve member is bonded or welded to the seat and then released by the application of the same energy to the bond joint. The valve member is held in place during the bonding by a clamping device. An appropriate force device can activate the opening and closing of the valve member. Various combinations of material for the valve member and valve seat can be utilized to provide an adequate sealing bond. Aluminum oxide, stainless steel, inconel, tungsten carbide as hard materials and copper, aluminum, titanium, silver, and gold as soft materials are suggested.

  8. Annealing of Co-Cr dental alloy: effects on nanostructure and Rockwell hardness

    PubMed Central

    Soylu, Elif Hilal; ?de, Semra; K?l?ç, Selim; Sipahi, Cumhur; Pi?kin, Bulent; Gökçe, Hasan Suat

    2013-01-01

    PURPOSE The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring 4 × 2 × 2 mm. Samples fabricated by a conventional casting technique (Group I) and prefabricated milling blanks (Group II) were examined as conventional technique groups. The DMLS samples were randomly divided into three groups as not annealed (Group III), annealed in argon atmosphere (Group IV), or annealed in oxygen atmosphere (Group V). The nanostructure was examined with the small-angle X-ray scattering method. The Rockwell hardness test was used to measure the hardness changes in each group, and the means and standard deviations were statistically analyzed by one-way ANOVA for comparison of continuous variables and Tukey's HSD test was used for post hoc analysis. P values of <.05 were accepted as statistically significant. RESULTS The general nanostructures of the samples were composed of small spherical entities stacked atop one another in dendritic form. All groups also displayed different hardness values depending on the manufacturing technique. The annealing procedure and environment directly affected both the nanostructure and hardness of the Co-Cr alloy. Group III exhibited a non-homogeneous structure and increased hardness (48.16 ± 3.02 HRC) because the annealing process was incomplete and the inner stress was not relieved. Annealing in argon atmosphere of Group IV not only relieved the inner stresses but also decreased the hardness (27.40 ± 3.98 HRC). The results of fitting function presented that Group IV was the most homogeneous product as the minimum bilayer thickness was measured (7.11 Å). CONCLUSION After the manufacturing with DMLS technique, annealing in argon atmosphere is an essential process for Co-Cr metal ceramic substructures. The dentists should be familiar with the materials that are used in clinic for prosthodontics treatments. PMID:24353888

  9. Phase transition induced by a shock wave in hard-sphere and hard-disk systems.

    PubMed

    Zhao, Nanrong; Sugiyama, Masaru; Ruggeri, Tommaso

    2008-08-01

    Dynamic phase transition induced by a shock wave in hard-sphere and hard-disk systems is studied on the basis of the system of Euler equations with caloric and thermal equations of state. First, Rankine-Hugoniot conditions are analyzed. The quantitative classification of Hugoniot types in terms of the thermodynamic quantities of the unperturbed state (the state before a shock wave) and the shock strength is made. Especially Hugoniot in typical two possible cases (P-1 and P-2) of the phase transition is analyzed in detail. In the case P-1 the phase transition occurs between a metastable liquid state and a stable solid state, and in the case P-2 the phase transition occurs through coexistence states, when the shock strength changes. Second, the admissibility of the two cases is discussed from a viewpoint of the recent mathematical theory of shock waves, and a rule with the use of the maximum entropy production rate is proposed as the rule for selecting the most probable one among the possible cases, that is, the most suitable constitutive equation that predicts the most probable shock wave. According to the rule, the constitutive equation in the case P-2 is the most promising one in the dynamic phase transition. It is emphasized that hard-sphere and hard-disk systems are suitable reference systems for studying shock wave phenomena including the shock-induced phase transition in more realistic condensed matters. PMID:18698913

  10. [Determination of copper alloy hardness, in original form and after casting as a function of casting techniques].

    PubMed

    Bombonatti, P E; de Barros, L E; Scaranelo, R M; Pellizzer, A J; Feitosa, S A

    1990-01-01

    It was evaluated the Vickers hardness of five high-copper casting alloys, in their original package form and after casting, according to the casting method used. That way, ten ingots, supplied by the manufacturers of each alloy, were included in self-curing acrylic resin, polished, numerated and submitted to Vickers hardness test at load of 200 g during 30 seconds. Afterwards the numerated ingots were removed from the acrylic resin and five of those were cast in an electrical casting machine and the other five in a centrifugal casting machine with an air/gas torch. The specimens obtained were included in self-curing acrylic resin, polished and submitted to Vickers hardness test. As a result it was verified that there is a variation of hardness among the alloys tested, and the use of the electrical casting machine produced lower hardness values than those produced when used the centrifugal casting machine with an air/gas torch. Also, there is a decrease of hardness of the cast alloys when they are tested in their original form and after casting. PMID:2099551

  11. A Group Orientation Approach for Facilitating the Work of Adjustment of the Hard-Core Unemployed. Final Report.

    ERIC Educational Resources Information Center

    Rosen, Hjalmar; Teahan, John E.

    The major objective of this project was to achieve a lasting integration of Negro hard-core unemployed men in an ongoing corporate work force. It was intended to develop values necessary for successful employment, particularly with regard to regularity of attendance, punctuality, conformity to work rules and regulations, and motivation to accept…

  12. Bottled drinking water: water contamination from bottle materials (glass, hard PET, soft PET), the influence of colour and acidification

    E-print Network

    Filzmoser, Peter

    Bottled drinking water: water contamination from bottle materials (glass, hard PET, soft PET- QMS) in 294 samples of the same bottled water (predominantly mineral water) sold in the European Union, Nb and Cu. Antimony has a 21x higher median value in bottled water when sold in PET-bottles (0.33 vs

  13. Bottled drinking water: Water contamination from bottle materials (glass, hard PET, soft PET), the influence of colour and acidification

    E-print Network

    Short, Daniel

    Bottled drinking water: Water contamination from bottle materials (glass, hard PET, soft PET-QMS) in 294 samples of the same bottled water (predominantly mineral water) sold in the European Union, Nb and Cu. Antimony has a 21Â higher median value in bottled water when sold in PET bottles (0.33 vs

  14. RAPID SPECTRAL CHANGES OF CYGNUS X-1 IN THE LOW/HARD STATE WITH SUZAKU

    SciTech Connect

    Yamada, S.; Makishima, K. [Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Negoro, H. [Department of Physics, College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Torii, S.; Noda, H. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mineshige, S. [Department of Astronomy, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-04-20

    Rapid spectral changes in the hard X-ray on a timescale down to {approx}0.1 s are studied by applying a ''shot analysis'' technique to the Suzaku observations of the black hole binary Cygnus X-1, performed on 2008 April 18 during the low/hard state. We successfully obtained the shot profiles, covering 10-200 keV with the Suzaku HXD-PIN and HXD-GSO detector. It is notable that the 100-200 keV shot profile is acquired for the first time owing to the HXD-GSO detector. The intensity changes in a time-symmetric way, though the hardness changes in a time-asymmetric way. When the shot-phase-resolved spectra are quantified with the Compton model, the Compton y-parameter and the electron temperature are found to decrease gradually through the rising phase of the shot, while the optical depth appears to increase. All the parameters return to their time-averaged values immediately within 0.1 s past the shot peak. We have not only confirmed this feature previously found in energies below {approx}60 keV, but also found that the spectral change is more prominent in energies above {approx}100 keV, implying the existence of some instant mechanism for direct entropy production. We discuss possible interpretations of the rapid spectral changes in the hard X-ray band.

  15. The potential energy landscape and inherent dynamics of a hard-sphere fluid

    E-print Network

    Qingqing Ma; Richard M. Stratt

    2014-08-13

    Hard-sphere models exhibit many of the same kinds of supercooled-liquid behavior as more realistic models of liquids, but the highly non-analytic character of their potentials makes it a challenge to think of that behavior in potential-energy-landscape terms. We show here that it is possible to calculate an important topological property of hard-sphere landscapes, the geodesic pathways through those landscapes, and to do so without artificially coarse-graining or softening the potential. We show, moreover, that the rapid growth of the lengths of those pathways with increasing packing fraction quantitatively predicts the precipitous decline in diffusion constants in a glass-forming hard-sphere mixture model. The geodesic paths themselves can be considered as defining the intrinsic dynamics of hard spheres, so it is also revealing to find that they (and therefore the features of the underlying potential-energy landscape) correctly predict the occurrence of dynamic heterogeneity and non-zero values of the non-Gaussian parameter. The success of these landscape predictions for the dynamics of such a singular model emphasizes that there is more to potential energy landscapes than is revealed by looking at the minima and saddle points.

  16. Potential energy landscape and inherent dynamics of a hard-sphere fluid

    NASA Astrophysics Data System (ADS)

    Ma, Qingqing; Stratt, Richard M.

    2014-10-01

    Hard-sphere models exhibit many of the same kinds of supercooled-liquid behavior as more realistic models of liquids, but the highly nonanalytic character of their potentials makes it a challenge to think of that behavior in potential energy landscape terms. We show here that it is possible to calculate an important topological property of hard-sphere landscapes, the geodesic pathways through those landscapes, and to do so without artificially coarse-graining or softening the potential. We show, moreover, that the rapid growth of the lengths of those pathways with increasing packing fraction quantitatively predicts the precipitous decline in diffusion constants in a glass-forming hard-sphere mixture model. The geodesic paths themselves can be considered as defining the intrinsic dynamics of hard spheres, so it is also revealing to find that they (and therefore the features of the underlying potential energy landscape) correctly predict the occurrence of dynamic heterogeneity and nonzero values of the non-Gaussian parameter. The success of these landscape predictions for the dynamics of such a singular model emphasizes that there is more to potential energy landscapes than is revealed by looking at the minima and saddle points.

  17. Hard X-ray spectra of cosmic gamma-ray bursts

    NASA Technical Reports Server (NTRS)

    Kane, S. R.; Share, G. H.

    1977-01-01

    Hard X-ray measurements of six gamma-ray bursts observed during the period from October 1969 to April 1971 are presented. The measurements were made with detectors on the OGO-5 and OSO-6 satellites. Spectra for five of the six bursts have been determined using measurements from both satellites in order to reduce ambiguities due to uncertain source locations. A significant fraction, about 20-60%, of the energy of the bursts falls in the hard X-ray range (20-130 keV). The time-integrated spectra have been fitted by power-law, exponential, and thermal-bremsstrahlung functions. They are consistent with power laws which steepen at energies of at least 150 keV, as reported earlier for two other bursts. Evidence for spectral variability from event to event in the hard X-ray region is presented. For a power-law representation, the power-law index has values ranging from approximately unity to 2.5. The hard X-ray spectra of the gamma-ray bursts differ significantly from those of the recently discovered 1-15-keV X-ray bursts.

  18. Nutritive value of fall-grown cereal-grain forages over time.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in nutritive value of fall-grown cereal-grain forages can affect cattle performance. The objective of this study was to evaluate the nutritive value of various fall-grown cereal-grain forages over time. One variety each of hard red (HR) and soft red (SR) winter wheat (Triticum aestivum L.), ...

  19. Nutritive Value of Fall-Grown Cereal-Grain Forages Over Time

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in nutritive value of fall-grown cereal-grain forages over time can affect cattle performance. The objective of this study was to evaluate nutritive values of various fall-grown cereal-grain forages over time. One variety each of hard red (HR) and soft red (SR) winter wheat (Triticum aesti...

  20. Working with Missing Values

    ERIC Educational Resources Information Center

    Acock, Alan C.

    2005-01-01

    Less than optimum strategies for missing values can produce biased estimates, distorted statistical power, and invalid conclusions. After reviewing traditional approaches (listwise, pairwise, and mean substitution), selected alternatives are covered including single imputation, multiple imputation, and full information maximum likelihood…

  1. Nutritive Value of Foods.

    E-print Network

    Anoymous,

    1982-01-01

    ] . . . , ..~ . . ~ .. - CONTENTS Page Explanation of the tables .................................................................... 1 Further information ......................................................................... 3 Index...) ............................................. 32 5 Food sources of additional nutrients ................................ . . . . . . . . . . . . . . . . . . . . . . .. 34 1 (Blank Pale to Origiaal BuUetlot .. , -.t . , . '~ .; * ? '."r NUTRITIVE VALUE OF FOODS Extension Foods...

  2. Value of Information References

    DOE Data Explorer

    Morency, Christina

    This file contains a list of relevant references on value of information (VOI) in RIS format. VOI provides a quantitative analysis to evaluate the outcome of the combined technologies (seismology, hydrology, geodesy) used to monitor Brady's Geothermal Field.

  3. Graphically Modeling Stakeholder Values

    NASA Astrophysics Data System (ADS)

    Stone, Harold L.

    2002-08-01

    This study was designed to give insight into the values considered in environmental policy and illustrate the respondents' personal constructions related to creating policy through the development of a graphic tool. Using both qualitative and quantitative methods, this study anonymously captured the intensity of values currently held by decision makers and tracked changes in values over time. Data were acquired through observations of and interviews with stakeholders in a five-year wetland mitigation bank permitting process at the Galveston District of the U.S. Army Corps of Engineers. The study included public and private sector respondents in both governmental and nongovernmental roles. The resulting representations of professional and personal stakeholders' values can be used as a tool for improving information exchange in policy negotiation and provides insight into the complexity of individual and corporate perceptions of a policy issue.

  4. Place Value Made Simple

    NSDL National Science Digital Library

    National Security Agency Central Security Service

    2009-05-19

    Students will read, write, and represent whole numbers from 0 - 1,000,000 using symbols, models, expanded form, and words. Base ten blocks, place value pocket charts, folded paper strips for expanded form accordions, and checks are used.

  5. Influence of plastic deformation upon the half-width of engineering metallic materials in hard state

    SciTech Connect

    Li, J.B.; Xu, H.B.; Chen, R.; Wang, Z.G. [Academia Sinica, Shenyang (China). State Key Lab. for Fatigue and Fracture of Materials

    1996-11-01

    The half-width values of the X-ray diffract profiles are frequently used to characterize the static strength of a strengthened surface, or the depth distribution of this mechanical parameter, in a strengthened surface layer, especially in a shot-peening affected layer. However, for the unpeened surface and the base material of the shot-peened specimen of an alloy steel treated in hard state, the experimental results shown in this article indicate that uniaxial tensile or compressive plastic deformation increases the yield strengths while it decreases the half-width values. The half-width values of the shot-peened surface and surface layer greatly decrease, whereas the yield strength of this surface remarkably increases. Accordingly, in the authors` opinion, the half-width values could not correctly describe the static strengths of hard metallic materials, and, contrary to the viewpoint put forward by a lot of researchers, the shot-peened surfaces of such materials are work hardened instead of work softened. A model demonstrating that plastic deformation reduces the half-width values by decreasing the second kind internal stresses is developed.

  6. The Expanding Place Value

    NSDL National Science Digital Library

    Erin Thomson

    2005-01-01

    This collection of three lesson plans is designed to provide students with practice understanding place value (0 to 999), using standard and word form to represent numbers, and using expanded form to represent place value. Each lesson plan provides activities that will help build student understanding of the concepts and practice to help reinforce the skill. Thirteen resource sheets are included and can be used with these lessons or as independent activities.

  7. Place Value Fun!

    NSDL National Science Digital Library

    Mr. Holmgren

    2005-10-25

    The activities on this page will help you to better understand place value in hundreds, tens and ones. -To start out think back on what you have learned about place value. We have learned that in our system of numbers we seperate numbers into hundreds, tens and ones. -Take out a piece of writing paper and place your name at the top. You will use this paper to ...

  8. Factors Which May Affect the Hardness of Cottonseed Cake. 

    E-print Network

    Fraps, G. S. (George Stronach); Marrs, C. D. (Cecil Douglas)

    1936-01-01

    to expectations. Meats with high nloisture content produced a soft cake. Storage for approximately two years had no appreciable effect npon the hardness of the cake. The direction of the testing load and the degree of smooth- ess of the test specimen had a... considerable effect npon the pparent hardness of the cake. Modified Brinell, schleroscope, abrasion, and impact tests . .:ere found unsuitable for testing the hardness of the cake. The crushing test, as already stated in a previous publication, mas found...

  9. Complete Classification of Bilinear HardCore Functions

    E-print Network

    Maurer, Ueli

    Complete Classification of Bilinear Hard­Core Functions Thomas Holenstein, Ueli Maurer, and Johan. A function h : {0, 1} n # {0, 1} m is called a hard­core function for f if, when given f(x) for a (secret) x function if it is hard­core for every one­way function f : {0, 1} n # {0, 1} l , where the second input

  10. Higher modes One "soft" and one "hard" wall

    E-print Network

    Berlin,Technische Universität

    1 Silencers · Higher modes ­ One "soft" and one "hard" wall y x a One wave: p(x,y,t)=p0 cos(k y)e-jk x e j t py(y,t)= 0 ; y=a xy } ky = (n+1/2) a Silencers · Higher modes ­ One "soft" and one "hard a { kx = -j (n+1/2)2( )2 -k0 2 a #12;2 Silencers · Higher modes ­ One "soft" and one "hard" wall · L 8

  11. Rate-hardness: a new performance metric for haptic interfaces

    Microsoft Academic Search

    Dale A. Lawrence; Lucy Y. Pao; Anne M. Dougherty; Mark A. Salada; Yiannis Pavlou

    2000-01-01

    Rate-hardness is introduced as a quality metric for hard virtual surfaces, and linked to human perception of hardness via a psychophysical study. A 3 degree-of-freedom haptic interface is used to present pairs of virtual walls to users for side-by-side comparison, 19 subjects are tested in a series of three blocks of trials, where different virtual walls are presented in randomly

  12. A heuristic radial distribution function for hard disks

    Microsoft Academic Search

    S. Bravo Yuste; A. Santos

    1993-01-01

    We propose a model radial distribution function for hard disks that is interpolated between the Percus–Yevick distribution functions for hard rods and hard spheres. The model contains a mixing parameter and two scaling parameters, which are determined by imposing self-consistency with an extension to d=2 of the Carnahan–Starling equation of state. Comparison with computer simulation is carried out.

  13. Radiation Hard AlGaN Detectors and Imager

    SciTech Connect

    None

    2012-05-01

    Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

  14. Does the temperature of beverages affect the surface roughness, hardness, and color stability of a composite resin?

    PubMed Central

    Tuncer, Duygu; Karaman, Emel; Firat, Esra

    2013-01-01

    Objective: To investigate the effect of beverages’ temperature on the surface roughness, hardness, and color stability of a composite resin. Materials and Methods: Fifty specimens of the Filtek Z250 composite (3M ESPE, Dental Products, St.Paul, MN, USA) were prepared and initial roughness, microhardness, and color were measured. Then the specimens were randomly divided into five groups of 10 specimens each: Coffee at 70°C, coffee at 37°C, cola at 10°C, cola at 37°C, and artificial saliva (control). After the samples were subjected to 15 min × 3 cycles per day of exposure to the solutions for 30 days, the final measurements were recorded. Results: After immersion in beverages, the artificial saliva group showed hardness values higher than those of the other groups (P < 0.001) and the microhardness values were significantly different from the initial values in all groups except for the control group. Both cola groups showed roughness values higher than the baseline values (P < 0.05), while the other groups showed values similar to the baseline measurements. When ?E measurements were examined, the 70°C coffee group showed the highest color change among all the groups (P < 0.05). Conclusion: High-temperature solutions caused alterations in certain properties of composites, such as increased color change, although they did not affect the hardness or roughness of the composite resin material tested. PMID:24883021

  15. Spectral (Hardness) Properties of X-Persei

    NASA Astrophysics Data System (ADS)

    Acuner, Zeynep

    We present the recent analysis results of Be-type high-mass X-ray binary X-Persei's energy dependent behaviour. For this investigation, we have made use of the Rossi X-ray Timing Explorer observations taken with the Proportional Counter Array, spanning the time interval between 1998 and 2003. Using the soft (3-7 to 7-10 keV) and hard energy bands (10-15 to 15-20 keV), we have examined the dependence X-Persei's previously published timing and spectral properties to different photon energies. We discuss these results suggesting the possibility of different accretion modes and a temporary accretion disk around the pulsar 4U 0352+309, assuming a quasi-spherical mass accretion emanating from the Be companion's stellar wind.

  16. Radiation Hardness Assurance (RHA) for Space Systems

    NASA Technical Reports Server (NTRS)

    Poivey, Christian; Buchner, Stephen

    2007-01-01

    This presentation discusses radiation hardness assurance (RHA) for space systems, providing both the programmatic aspects of RHA and the RHA procedure. RHA consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the space radiation environment. RHA also pertains to environment definition, part selection, part testing, spacecraft layout, radiation tolerant design, and mission/system/subsystems requirements. RHA procedure consists of establishing mission requirements, defining and evaluating the radiation hazard, selecting and categorizing the appropriate parts, and evaluating circuit response to hazard. The RHA approach is based on risk management and is confined only to parts, it includes spacecraft layout, system/subsystem/circuit design, and system requirements and system operations. RHA should be taken into account in the early phases of a program including the proposal and feasibility analysis phases.

  17. The Harding move: Opening up new horizons

    SciTech Connect

    Feith, J.; Hoekstra, R.J.P.

    1996-12-31

    During July--September 1995 Dockwise successfully completed the unique load-out, transport and discharge operation of the 22,870 ton BP-Harding PDQ-unit (Production Drilling and Quarters) from Korea to the North Sea via the Suez Canal on board the self-propelled heavy-lift vessel Transshelf. This unique loading operation involved skidding the 22,870 ton platform via the side of the vessel over four skidbeams. Special solutions had to be found for stability, load spreading, mooring, ballasting and maneuvering. Due to the 2.6 meter grillage height, special procedures were required for maintaining stability during discharge by float-off. The experience gained in this project may lead to a further extension of load-out and transport possibilities on a worldwide scale, utilizing the presently available fleet of heavy-lift vessels.

  18. ModelCentric Smart Grid Workshop: From Hard Dollar Justification to RealTime Control and the Analytics That Make It Possible

    E-print Network

    Ohta, Shigemi

    Agenda ModelCentric Smart Grid Workshop: From Hard Dollar Justification to RealTime Control managers and technical personnel involved with smart grid activities. The second day takes a deeper dive:30 p.m. Smart Grid "harddollar" value streams ­ an incremental value approach Efficiency

  19. Mechanical Properties of Chocolate: How Hard is your Chocolate?

    NSDL National Science Digital Library

    2007-12-20

    Hardness is probably a concept you are well familiar with. You already know that certain materials are harder than others; in fact, you prove it everyday when you chew your food and your teeth don’t break (because your teeth are harder than the foods you chew). Hardness can be defined as a material's ability to resist a change in shape. Modern hardness testers take a well-defined shape and press it into a material with a certain force, observing the indent it leaves in the material when it is removed. In this lesson, you will be performing hardness testing on different bars of chocolate.

  20. Coendangered hard-ticks: threatened or threatening?

    PubMed Central

    2011-01-01

    The overwhelming majority of animal conservation projects are focused on vertebrates, despite most of the species on Earth being invertebrates. Estimates state that about half of all named species of invertebrates are parasitic in at least one stage of their development. The dilemma of viewing parasites as biodiversity or pest has been discussed by several authors. However, ticks were omitted. The latest taxonomic synopses of non-fossil Ixodidae consider valid 700 species. Though, how many of them are still extant is almost impossible to tell, as many of them are known only from type specimens in museums and were never collected since their original description. Moreover, many hosts are endangered and as part of conservation efforts of threatened vertebrates, a common practice is the removal of, and treatment for external parasites, with devastating impact on tick populations. There are several known cases when the host became extinct with subsequent coextinction of their ectoparasites. For our synoptic approach we have used the IUCN status of the host in order to evaluate the status of specifically associated hard-ticks. As a result, we propose a number of 63 coendangered and one extinct hard-tick species. On the other side of the coin, the most important issue regarding tick-host associations is vectorial transmission of microbial pathogens (i.e. viruses, bacteria, protozoans). Tick-borne diseases of threatened vertebrates are sometimes fatal to their hosts. Mortality associated with pathogens acquired from ticks has been documented in several cases, mostly after translocations. Are ticks a real threat to their coendangered host and should they be eliminated? Up to date, there are no reliable proofs that ticks listed by us as coendangered are competent vectors for pathogens of endangered animals. PMID:21554736

  1. Deglaciation mechanisms for a paleoproterozoic hard snowball

    NASA Astrophysics Data System (ADS)

    Pierrehumbert, R. T.; Mitchell, J.; Levine, X.

    2006-05-01

    Our earlier work on the Neoproterozoic hard snowball climate indicated that very high CO2 thresholds would be needed for deglaciation, owing to lapse rate feedbacks and snow cover effects that are not represented in standard energy balance models. We examine here a range of similar issues for the Paleoproterozoic, at which time the Sun was still fainter, but the geothermal heat flux was larger. The warmest position in a hard snowball climate occurs in the Summer subtropics, and we have found that many salient features of the climate there can be reproduced using a radiative-convective model, since the lateral heat fluxes are weak in this case. We show that the radiative-convective model reproduces the low tropopause height that leads to a weak greenhouse effect in full GCM simulations. We exploit this simplification to explore the role of surface boundary layer fluxes and atmospheric solar heating in determining the CO2 threshold for deglaciation. This technique is used to estimate deglaciation thresholds for the Paleoproterozoic. Cloud feedbacks remain a major source of uncertainty, but we remark that the shallow depth reached by convection makes extensive high cloud cover unlikely. We discuss also two aspects of ice dynamics that may be relevant to Paleoproterozoic climate and chemistry. The first is the "thin ice" solution proposed by McKay, shot down by Warren et al, but recently tentatively reinvigorated by Pollard and Kasting in the context of an energy balance model. We discuss the problem of whether such solutions are compatible with the lateral heat flux, vertical sensible heat transfer, and snow cover yielded by full GCM simulations, taking cognizance also of the higher geothermal heat flux estimated for the Paleoproterozoic. Finally, we provide some estimates of the mean age of "sea glacier" ice in Paleoproterozoic conditions, which is relevant to the prospects for a H2O2-based oxygenation theory proposed recently by Liang et al.

  2. Prognostic Value of Multidetector Computed Tomography Coronary Angiography in Diabetes

    PubMed Central

    Andreini, Daniele; Pontone, Gianluca; Mushtaq, Saima; Bertella, Erika; Conte, Edoardo; Baggiano, Andrea; Veglia, Fabrizio; Agostoni, Piergiuseppe; Annoni, Andrea; Formenti, Alberto; Montorsi, Piero; Ballerini, Giovanni; Bartorelli, Antonio L.; Fiorentini, Cesare; Pepi, Mauro

    2013-01-01

    OBJECTIVE To assess the prognostic role of multidetector computed tomography coronary angiography (MDCT-CA) in patients with diabetes with suspected coronary artery disease (CAD). Use of MDCT-CA is increasing in patients with suspected CAD. However, data supporting its prognostic value in patients with diabetes are limited. RESEARCH DESIGN AND METHODS Between January 2006 and September 2007, 429 consecutive diabetic patients were prospectively studied with MDCT-CA for detecting the presence and assessing the extent of CAD (disease extension and coronary plaque scores). Patients were classified according to the presence of normal coronary arteries and nonobstructive (<50%) and obstructive (?50%) coronary lesions. The composite rates of hard cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina) and all cardiac events (including revascularization) were the end points of the study. RESULTS Twenty-four patients were excluded because MDCT-CA data were not able to be interpreted. Of the remaining 405 patients, clinical follow-up (mean 62 ± 9 months) was obtained in 390 (98%). Multivariate analysis showed that predictors of hard and all events were obstructive CAD, three-vessel CAD, and left main coronary artery (LMCA) disease. Cumulative event-free survival was 100% for hard and all events in patients with normal coronary arteries, 78% for hard events and 56% for all events in patients with nonobstructive CAD, and 60% for hard events and 16% for all events in patients with obstructive CAD. Three-vessel CAD and LMCA disease were associated with a higher rate of hard cardiac events. CONCLUSIONS MDCT-CA provides long-term prognostic information for patients with diabetes with suspected CAD, showing excellent prognosis when there is no evidence of atherosclerosis and allowing risk stratification when CAD is present. PMID:23801796

  3. Hard X-ray emission from the galaxy cluster A2256

    E-print Network

    Fusco-Femiano, R; De Grandi, S; Feretti, L; Giovannini, G; Grandi, P; Malizia, A; Matt, G; Molendi, S

    2000-01-01

    After the positive detection by BeppoSAX of hard X-ray radiation up to ~80 keV in the Coma cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6sigma confidence level. In addition to this power law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, not surprisingly given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the PDS onboard BeppoSAX is marginally consistent with that expected by the inverse Compton model. A value of ~0.05 microG is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of \\~0.5 microG could be present in the central radio halo, likely related to the hard tail detected by ASCA.

  4. Hard X-ray emission from the galaxy cluster A2256

    E-print Network

    R. Fusco-Femiano; D. Dal Fiume; S. De Grandi; L. Feretti; G. Giovannini; P. Grandi; A. Malizia; G. Matt; S. Molendi

    2000-03-13

    After the positive detection by BeppoSAX of hard X-ray radiation up to ~80 keV in the Coma cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6sigma confidence level. In addition to this power law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, not surprisingly given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the PDS onboard BeppoSAX is marginally consistent with that expected by the inverse Compton model. A value of ~0.05 microG is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of \\~0.5 microG could be present in the central radio halo, likely related to the hard tail detected by ASCA.

  5. Getting Value from Research

    NASA Astrophysics Data System (ADS)

    Duke, Charles

    2004-03-01

    During the past decade the environment for and execution of industrial research has changed profoundly, as recently documented in Robert Buderi, Engines of Tomorrow (Simon and Shuster, New York, 2000). The vertically integrated single-firm research-through-product value chains of the twentieth century are gone, replaced by value chains the various elements of which can come from different firms in different parts of the world as described, e.g., by Henry W. Cheesbrough, Open Innovation (Harvard Business School Press, Boston, 2003). The consequences of this change are profound for national R policy, the R strategies of specific firms, and individual researchers. (See e.g., C. B. Duke, How to get value from R, Physics World, 17 (August 1997), 17.) In this presentation I sketch the strategies that firms employ to generate value from their research. Then I discuss the ingredients that are required to implement these strategies by creating value chains to deliver the fruits of research to customers. I indicate how the role of physical sciences is changing as unique hardware, based on advanced research in the physical sciences, becomes an increasingly minor (and often outsourced) component of integrated systems offerings. I close by noting implications of these developments on the nature of the careers that physicists can expect in industry and on the skills and cultural attributes that are required to be successful in the new industrial research environment.

  6. Nanoindentation of soft films on hard substrates: Experiments and finite element simulations

    SciTech Connect

    Pharr, G.M.; Tsui, T.Y. [Rice Univ., Houston, TX (United States). Dept. of Materials Science; Bolshakov, A. [Baker Hughes Inteq, Houston, TX (United States); Hay, J.C. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    Experiments and finite element simulations have been performed to examine error measurement of hardness and elastic modulus caused by pile-up when soft films deposited on hard substrates are tested by nanoindentation methods. Pile-up is exacerbated in soft-film/hard-substrate systems by the constraint imposed on plastic deformation in the film by the relatively non-deformable substrate. To experimentally examine pile-up effects, soft aluminum films with thicknesses of 240, 650, and 1700 nm were deposited on hard soda-lime glass substrates and tested by nanoindentation techniques. This system is attractive because the elastic modulus of the film and the substrate are approximately the same, but the substrate is harder than the film by a factor of about ten. Consequently, substrate influences on the indentation load-displacement behavior are manifested primarily by differences in the plastic flow characteristics alone. The elastic modulus of the film/substrate system, as measured by nanoindentation techniques, exhibits an increase with indenter penetration depth which peaks at a value approximately 30% greater than the true film modulus at a penetration depth close to the film thickness. Finite element simulation shows that this unusual behavior is caused by substrate-induced enhancement of pile-up. Finite element simulation also shows that the amount of pile-up increases with increasing penetration depth, and that the pile-up geometry depends on the work-hardening characteristics of the film. Because of these effects, nanoindentation techniques overestimate the true film hardness and elastic modulus by as much as 68% and 35%, respectively, depending on the work-hardening behavior of the film and the indenter penetration depth. The largest errors occur in non-work-hardening materials at penetration depths close to the film thickness, for which substrate-induced enhancement of pile-up is greatest.

  7. Relative value health insurance.

    PubMed

    Korobkin, Russell

    2014-04-01

    Increases in health costs continue to outpace general inflation, and implementation of the Patient Protection and Affordable Care Act will exacerbate the problem by adding more Americans to the ranks of the insured. The most commonly proposed solutions--bureaucratic controls, greater patient cost sharing, and changes to physician incentives--all have substantial weaknesses. This article proposes a new paradigm for rationalizing health care expenditures called "relative value health insurance," a product that would enable consumers to purchase health insurance that covers cost-effective treatments but excludes cost-ineffective treatments. A combination of legal and informational impediments prevents private insurers from marketing this type of product today, but creative use of comparative effectiveness research, funded as a part of health care reform, could make relative value health insurance possible. Data deficits, adverse selection risks, and heterogeneous values among consumers create obstacles to shifting the health insurance system to this paradigm, but they could be overcome. PMID:24523448

  8. Quantum Searches in a Hard 2SAT Ensemble

    E-print Network

    Neuhaus Thomas

    2014-12-17

    Using a recently constructed ensemble of hard 2SAT realizations, that has a unique ground-state we calculate for the quantized theory the median gap correlation length values $\\xi_{GAP}$ along the direction of the quantum adiabatic control parameter $\\lambda$. We use quantum annealing (QA) with transverse field and a linear time schedule in the adiabatic control parameter $\\lambda$. The gap correlation length diverges exponentially $\\xi_{\\rm GAP} \\propto {\\rm exp} [+r_{\\rm GAP}N]$ in the median with a rate constant $r_{\\rm GAP}=0.553(6)$, while the run time diverges exponentially $\\tau_{\\rm QA} \\propto {\\rm exp} [+r_{\\rm QA}N]$ with $r_{\\rm QA}=1.184(16)$. Simulated classical annealing (SA) exhibits a run time rate constant $r_{\\rm SA}=0.340(5)$ that is small and thus finds ground-states exponentially faster than QA. There are no quantum speedups in ground state searches on constant energy surfaces that have exponentially large volume. We also determine gap correlation length distribution functions $P(\\xi_{\\rm GAP})d\\xi_{\\rm GAP} \\approx W_k$ over the ensemble that at $N=18$ are close to Weibull functions $W_k$ with $k \\approx 1.2$ i.e., the problems show thin catastrophic tails in $\\xi_{\\rm GAP}$. The inferred success probability distribution functions of the quantum annealer turn out to be bimodal.

  9. From Lyapunov modes to their exponents for hard disk systems.

    PubMed

    Chung, Tony; Truant, Daniel; Morriss, Gary P

    2010-06-01

    We demonstrate the preservation of the Lyapunov modes in a system of hard disks by the underlying tangent space dynamics. This result is exact for the Zero modes and correct to order ? for the Transverse and Longitudinal-Momentum modes, where ? is linear in the mode number. For sufficiently large mode numbers, the ? terms become significant and the dynamics no longer preserves the mode structure. We propose a modified Gram-Schmidt procedure based on orthogonality with respect to the center zero space that produces the exact numerical mode. This Gram-Schmidt procedure can also exploit the orthogonality between conjugate modes and their symplectic structure in order to find a simple relation that determines the Lyapunov exponent from the Lyapunov mode. This involves a reclassification of the modes into either direction preserving or form preserving. These analytic methods assume a knowledge of the ordering of the modes within the Lyapunov spectrum, but gives both predictive power for the values of the exponents from the modes and describes the modes in greater detail than was previously achievable. Thus the modes and the exponents contain the same information. PMID:20866502

  10. Hard proximity induced superconducting gap in semiconductor - superconductor epitaxial hybrids

    NASA Astrophysics Data System (ADS)

    Jespersen, Thomas; Krogstrup, Peter; Ziino, Nino; Albrecht, Sven; Chang, Willy; Madsen, Morten; Johnson, Erik; Kuemmeth, Ferdinand; Nygård, Jesper; Marcus, Charles

    2015-03-01

    We present molecular beam epitaxy grown InAs semiconductor nanowires capped with a shell of aluminum (superconductor). The hybrid wires are grown without breaking vacuum, resulting in an epitaxial interface between the two materials as demonstrated by detailed transmission electron microscopy and simulations. The domain matching at the interface is discussed. Incorporating the epitaxial nanowire hybrids in electrical devices we performed detailed tunneling spectroscopy of the proximity induced superconducting gap in the InAs core at 20 mK. We find the sub-gap conductance being at least a factor 200 smaller than the normal state value (gap hardness). This is a significant improvement compared to devices fabricated by conventional lithographic methods and metal evaporation showing no more than a factor of ~ 5 . The epitaxial hybrids seem to solve the soft gap problem associated with the use of nanowire hybrids for future applications in topological quantum information based on Majorana zero modes. Research supported by Microsoft Station Q, Danish National Research Foundation, Villum Foundation, Lundbeck Foundation, and the European Commission.

  11. Simulating asymmetric colloidal mixture with adhesive hard sphere model.

    PubMed

    Jamnik, A

    2008-06-21

    Monte Carlo simulation and Percus-Yevick (PY) theory are used to investigate the structural properties of a two-component system of the Baxter adhesive fluids with the size asymmetry of the particles of both components mimicking an asymmetric binary colloidal mixture. The radial distribution functions for all possible species pairs, g(11)(r), g(22)(r), and g(12)(r), exhibit discontinuities at the interparticle distances corresponding to certain combinations of n and m values (n and m being integers) in the sum nsigma(1)+msigma(2) (sigma(1) and sigma(2) being the hard-core diameters of individual components) as a consequence of the impulse character of 1-1, 2-2, and 1-2 attractive interactions. In contrast to the PY theory, which predicts the delta function peaks in the shape of g(ij)(r) only at the distances which are the multiple of the molecular sizes corresponding to different linear structures of successively connected particles, the simulation results reveal additional peaks at intermediate distances originating from the formation of rigid clusters of various geometries. PMID:18570507

  12. The impulsive hard X-rays from solar flares

    NASA Technical Reports Server (NTRS)

    Leach, J.

    1984-01-01

    A technique for determining the physical arrangement of a solar flare during the impulsive phase was developed based upon a nonthermal model interpretation of the emitted hard X-rays. Accurate values are obtained for the flare parameters, including those which describe the magnetic field structure and the beaming of the energetic electrons, parameters which have hitherto been mostly inaccessible. The X-ray intensity height structure can be described readily with a single expression based upon a semi-empirical fit to the results from many models. Results show that the degree of linear polarization of the X-rays from a flaring loop does not exceed 25 percent and can easily and naturally be as low as the polarization expected from a thermal model. This is a highly significant result in that it supersedes those based upon less thorough calculations of the electron beam dynamics and requires that a reevaluation of hopes of using polarization measurements to discriminate between categories of flare models.

  13. Hard X-ray polarimetry with Astrosat-CZTI

    NASA Astrophysics Data System (ADS)

    Vadawale, S. V.; Chattopadhyay, T.; Rao, A. R.; Bhattacharya, D.; Bhalerao, V. B.; Vagshette, N.; Pawar, P.; Sreekumar, S.

    2015-06-01

    X-ray polarimetry is largely an unexplored area of an otherwise mature field of X-ray astronomy. Except for a few early attempts during the 1970s, no dedicated X-ray polarimeter has been flown during the past four decades. On the other hand, the scientific value of X-ray polarization measurement has been well known for a long time, and there has been significant technical progress in developing sensitive X-ray polarimeters in recent years. But there are no approved dedicated X-ray polarimetric experiments to be flown in the near future, so it is important to explore the polarimetric capabilities of other existing or planned instruments and examine whether they can provide significant astrophysical polarization measurements. In this paper, we present experimental results to show that the CZTI instrument onboard the forthcoming Indian astronomy mission, Astrosat, will be able to provide sensitive measurements of X-ray polarization in the energy range of 100-300 keV. CZTI will be able to constrain any intrinsic polarization greater than ~40% for bright X-ray sources (>500 mCrab) within a short exposure of ~100 ks with a 3-sigma confidence level. We show that this seemingly "modest" sensitivity can play a very significant role in addressing long pending questions, such as the contribution of relativistic jets to hard X-rays in black hole binaries and X-ray emission mechanism and geometry in X-ray pulsars.

  14. Self-healing phenomenon and dynamic hardness of C60-based nanocomposite coatings.

    PubMed

    Penkov, Oleksiy V; Pukha, Volodymyr E; Devizenko, Alexander Yu; Kim, Hae-Jin; Kim, Dae-Eun

    2014-05-14

    The phenomenon of surface self-healing in C60-based polymer coatings deposited by ion-beam assisted physical vapor deposition was investigated. Nanoindentation of the coatings led to the formation of a protrusion rather than an indent. This protrusion was accompanied by an abnormal shape of the force-distance curve, where the unloading curve lies above the loading curve due to an additional force applied in pulling the indenter out of the media. The coatings exhibited a nanocomposite structure that was strongly affected by the ratio of C60 ion and C60 molecular beam intensities during deposition. The coatings also demonstrated the dynamic hardness effect, where the effective value of the hardness depends significantly on the indentation speed. PMID:24697539

  15. Lyapunov Instability for a hard-disk fluid in equilibrium and nonequilibrium thermostated by deterministic scattering

    E-print Network

    C. Wagner

    2000-01-10

    We compute the full Lyapunov spectra for a hard-disk fluid under temperature gradient and shear. The system is thermalized by deterministic and time-reversible scattering at the boundary. This thermostating mechanism allows for energy fluctuations around a mean value which is reflected by only two vanishing Lyapunov exponents in equilibrium and nonequilibrium. The Lyapunov exponents are calculated with a recently developed formalism for systems with elastic hard collisions. In a nonequilibrium steady state the average phase space volume is contracted onto a fractal attractor leading to a negative sum of Lyapunov exponents. Since the system is driven inhomogeneously we do not expect the conjugate pairing rule to hold which is confirmed numerically.

  16. Equation of state of nonadditive d-dimensional hard-sphere mixtures

    NASA Astrophysics Data System (ADS)

    Santos, A.; López de Haro, M.; Yuste, S. B.

    2005-01-01

    An equation of state for a multicomponent mixture of nonadditive hard spheres in d dimensions is proposed. It yields a rather simple density dependence and constitutes a natural extension of the equation of state for additive hard spheres proposed by us [A. Santos, S. B. Yuste, and M. López de Haro, Mol. Phys. 96, 1 (1999)]. The proposal relies on the known exact second and third virial coefficients and requires as input the compressibility factor of the one-component system. A comparison is carried out both with another recent theoretical proposal based on a similar philosophy and with the available exact results and simulation data in d=1, 2, and 3. Good general agreement with the reported values of the virial coefficients and of the compressibility factor of binary mixtures is observed, especially for high asymmetries and/or positive nonadditivities.

  17. Microstructural characterization and hardness properties of electric resistance welding titanium joints for dental applications.

    PubMed

    Ceschini, Lorella; Boromei, Iuri; Morri, Alessandro; Nardi, Diego; Sighinolfi, Gianluca; Degidi, Marco

    2015-06-01

    The electric resistance welding procedure is used to join a titanium bar with specific implant abutments in order to produce a framework directly in the oral cavity of the patient. This investigation studied the effects of the welding process on microstructure and hardness properties of commercially pure (CP2 and CP4) Ti components. Different welding powers and cooling procedures were applied to bars and abutments, normally used to produce the framework, in order to simulate the clinical intraoral welding procedure. The analyses highlighted that the joining process did not induce appreciable changes in the geometry of the abutments. However, because of unavoidable microstructural modifications in the welded zones, the hardness decreased to values lower than those of the unwelded CP2 and CP4 Ti grades, irrespective of the welding environments and parameters. PMID:26045042

  18. Soft-and-Hard/D'B' Boundary Conditions and their Realization by Electromagnetic Media

    E-print Network

    I. V. Lindell; A. Sihvola

    2012-04-12

    A layer of uniaxial medium with large axial permittivity and permeability can be used as a quarter-wave transformer with interesting properties. By increasing the transverse permittivity and permeability the transformer becomes a thin sheet. It is shown that the recently introduced SHDB boundary conditions, generalizing the soft-and-hard and DB conditions, realized by the interface of a skewon-axion medium, can be transformed to form a novel class of SHD'B' boundary conditions which generalizes the soft-and-hard and D'B' boundary conditions. Reflection of a plane wave from a planar SHD'B' boundary is considered by numerical examples revealing an interesting narrow beam with radical change of reflection for certain values of parameters and incidence angles.

  19. Transfinite mean value interpolation

    Microsoft Academic Search

    Christopher Dyken; Michael S. Floater

    2009-01-01

    Transfinite mean value interpolation has recently emerged as a simple and robust way to interpolate a function f defined on the boundary of a planar domain. In this paper we study basic properties of the interpolant, including sufficient conditions on the boundary of the domain to guarantee interpolation when f is continuous. Then, by deriving the normal derivative of the

  20. The HPT Value Proposition.

    ERIC Educational Resources Information Center

    Brethower, Dale

    2003-01-01

    Discusses the use of HPT (human performance technology) to get results that add value. Topics include ISD (instructional systems design) and desired results, other than achieving agreed-on learning objectives; cost effectiveness; systemic approaches; and results that can be seen in the performance of individuals. (LRW)

  1. Valuing intervention and observation

    Microsoft Academic Search

    David W. Green; David E. Over

    2009-01-01

    Understanding causal relations is fundamental to effective action but causal data can be confounded. We examined the value that participants placed on data derived from a hypothetical intervention or observation. Our materials involved a possible cause (“bottled water”), a possible confound (“food”), and a context (“a restaurant”). We supposed that participants seek to draw as specific a causal inference as

  2. Values and Scientists.

    ERIC Educational Resources Information Center

    White, John A.

    Science and technology are in trouble today. And the world of people and of other living things is in trouble because of them. This seven-part book provides an introduction to the origin and nature of these troubles. Major areas considered in the first six parts are: (1) values; (2) science and technology in an ideal world (examining growth of…

  3. Technostress and Library Values.

    ERIC Educational Resources Information Center

    Gorman, Michael

    2001-01-01

    Discusses information overload and society's and libraries' responses to technology. Considers eight values that libraries should focus on and how they relate to technology in libraries: democracy, stewardship, service, intellectual freedom, privacy, rationalism, equity of access, and building harmony and balance. (LRW)

  4. Choices, Values, and Frames

    Microsoft Academic Search

    Daniel Kahneman; Amos Tversky

    1984-01-01

    We discuss the cognitive and the psy- chophysical determinants of choice in risky and risk- less contexts. The psychophysics of value induce risk aversion in the domain of gains and risk seeking in the domain of losses. The psychophysics of chance induce overweighting of sure things and of improbable events, relative to events of moderate probability. De- cision problems can

  5. Measuring Value in Healthcare

    Microsoft Academic Search

    Christopher Gardner

    2008-01-01

    A statistical description and model of individual healthcare expenditures in the US has been developed for measuring value in healthcare. We find evidence that healthcare expenditures are quantifiable as an infusion-diffusion process, which can be thought of intuitively as a steady change in the intensity of treatment superimposed on a random process reflecting variations in the efficiency and effectiveness of

  6. Art's Perspective on Value.

    ERIC Educational Resources Information Center

    Haldane, John J.

    1983-01-01

    The artist experiences the world and extracts from it elements that have worth. The study of art is a training in perception. Children should be introduced to works of quality and should be encouraged in their own artistic activity because art educates their responsiveness to values. (CS)

  7. Communication and Values.

    ERIC Educational Resources Information Center

    Sillars, Malcolm O.

    Communication experts and researchers have done little to help prepare themselves or others to cope with values in the communication revolution that is taking place. The problem goes beyond the influence the media has in the United States; it has implications of international issues of survival. What is needed is an emphasis on research and…

  8. Planting Seeds - Growing Values

    ERIC Educational Resources Information Center

    Schubert, Judith L.

    2004-01-01

    Nurturing positive values with youth often involves connecting with them during times of internal struggle and relating these struggles to external influences in their lives. Care and support provided by adults is crucial in these times, even when a youth's outward expression of struggles create conflict or concern. In this article, the author…

  9. Ethics and Value Education

    ERIC Educational Resources Information Center

    Callahan, Daniel

    1978-01-01

    The teaching of ethics and values is a concern of American education. Scientific and technological developments and the responsibilities of professional life and of personal morality are discussed. Steps to a quality program in ethics, and the need for a theoretical framework are also addressed. (SW)

  10. The value of data

    Microsoft Academic Search

    Herman van Haagen; Christine Chichester; Peter-Bram't Hoen; Johan T den Dunnen; Gertjan van Ommen; Erik van Mulligen; Bharat Singh; Rob Hooft; Marco Roos; Joel Hammond; Bruce Kiesel; Belinda Giardine; Jan Velterop; Paul Groth; Erik Schultes; Barend Mons

    2011-01-01

    Data citation and the derivation of semantic constructs directly from datasets have now both found their place in scientific communication. The social challenge facing us is to maintain the value of traditional narrative publications and their relationship to the datasets they report upon while at the same time developing appropriate metrics for citation of data and data constructs.

  11. On weighted Shapley values

    Microsoft Academic Search

    E. Kalai; D. Samet

    1987-01-01

    Nonsymmetric Shapley values for coalitional form games with transferable utility are studied. The nonsymmetries are modeled through nonsymmetric weight systems defined on the players of the games. It is shown axiomatically that two families of solutions of this type are possible. These families are strongly related to each other through the duality relationship on games. While the first family lends

  12. Economic Value of Veterinary

    E-print Network

    Economic Value of Veterinary Diagnostics Public Investment in Animal Health Testing Yields Economic Benefits TEXAS VETERINARY MEDICAL DIAGNOSTIC LABORATORY TEXAS A&M SYSTEM #12;The Texas Veterinary Medical figure on these activities, scientific studies have shown a cost-benefit ratio of 1:10 for veterinary

  13. Fair Value Accounting

    Microsoft Academic Search

    Michel Magnan; Daniel Thornton

    2009-01-01

    The paper provides a genesis of fair value accounting (FVA) and reviews some research and empirical evidence that are relevant to the debate surrounding its use. We also comment on FVA’s role in the financial crisis: was it just the messenger of bad news or was it “procyclical,” contributing to the sad state of the economy in addition to reporting

  14. Place Value Mathlets

    NSDL National Science Digital Library

    2014-01-01

    This series of interactive JavaScript applets helps children understand place value in our base-10 system. The mathlets provide visual models of what happens as one counts by various powers of 10 in a progression from single units to tokens representing groups to a position-based numeration system. The resource includes an explanation of each applet.

  15. Value of Traditions

    ERIC Educational Resources Information Center

    Brewer, Marilynn B.; And Others

    1976-01-01

    Presents pro and con comments with regards to 1975 APA presidential address under the heading of the value of traditions. Other comments are subsumed under the headings of biological versus social evolution, and the genetic basis of behavior especially of altruism. (Author/AM)

  16. Decimal Place Value Recognition

    NSDL National Science Digital Library

    Mrs. Wells

    2008-07-22

    You will learn to recognize decimal numbers and their word names. Now that you have been given instruction on converting decimal names to numerical value, you will be able to show your competency. Work through each section below. As you complete each section, before beginning the next section, show and report your scores to the teacher for credit. Section 1: ...

  17. Valuing socio-diversity

    Microsoft Academic Search

    Sabine U. O’Hara

    1995-01-01

    The loss of bio-diversity has received increasing attention as one of the most serious environmental threats we face. Yet not only biodiversity is being lost at staggering rates, socio-diversity is being lost as well. Sociodiversity is defined as the various social and economic arrangements by which people organize their societies, particularly the underlying assumptions, goals, values and social behaviours guiding

  18. Values and Society.

    ERIC Educational Resources Information Center

    Nelson, Jack L.

    The idea of a democratic society based on human rights and social justice is the social issue examined in this book which is one of a series on challenges and choices in American values. The format followed in the series includes the following for secondary students: case studies illustrating the issue by focusing on human institutions, factual…

  19. Psychotherapy and religious values

    Microsoft Academic Search

    Allen E. Bergin

    1980-01-01

    Describes the alienation of therapeutic psychology from religious values in contrast to the growing professional and public interest in religious experience and commitment. Six theses aimed at broadening clinical psychology's scope to include religion more systematically in theories, research, and techniques, especially as they bear on personality and psychotherapy, are presented and documented. The theses include a contrast between dominant

  20. Reliability and Validity of Quantifying Absolute Muscle Hardness Using Ultrasound Elastography

    PubMed Central

    Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

    2012-01-01

    Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young’s moduli of seven tissue-mimicking materials (in vitro; Young’s modulus range, 20–80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young’s modulus ratio of two reference materials, one hard and one soft (Young’s moduli of 7 and 30 kPa, respectively), the Young’s moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (?6.9%) and substantially high intraclass correlation coefficients (?0.77) obtained from all measurements. The correlation coefficient between the Young’s moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young’s moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified. PMID:23029231

  1. Radiology's value chain.

    PubMed

    Enzmann, Dieter R

    2012-04-01

    A diagnostic radiology value chain is constructed to define its main components, all of which are vulnerable to change, because digitization has caused disaggregation of the chain. Some components afford opportunities to improve productivity, some add value, while some face outsourcing to lower labor cost and to information technology substitutes, raising commoditization risks. Digital image information, because it can be competitive at smaller economies of scale, allows faster, differential rates of technological innovation of components, initiating a centralization-to-decentralization technology trend. Digitization, having triggered disaggregation of radiology's professional service model, may soon usher in an information business model. This means moving from a mind-set of "reading images" to an orientation of creating and organizing information for greater accuracy, faster speed, and lower cost in medical decision making. Information businesses view value chain investments differently than do small professional services. In the former model, producing a better business product will extend image interpretation beyond a radiologist's personal fund of knowledge to encompass expanding external imaging databases. A follow-on expansion with integration of image and molecular information into a report will offer new value in medical decision making. Improved interpretation plus new integration will enrich and diversify radiology's key service products, the report and consultation. A more robust, information-rich report derived from a "systems" and "computational" radiology approach will be facilitated by a transition from a professional service to an information business. Under health care reform, radiology will transition its emphasis from volume to greater value. Radiology's future brightens with the adoption of a philosophy of offering information rather than "reads" for decision making. Staunchly defending the status quo via turf wars is unlikely to constitute a forward-looking, competitive strategy. PMID:22438447

  2. Capability Profile of Hard Cutting and Grinding Processes

    Microsoft Academic Search

    F. Klocke; E. Brinksmeier; K. Weinert

    2005-01-01

    This keynote paper aims at matching the supply of research results with the industrial demands in hard cutting and grinding. The capability profiles of the processes are characterised and several manufacturing solutions are discussed. The comparison of hard cutting and grinding operations is carried out with regard to certain evaluation criteria based on the functionality of the machined workpiece itself,

  3. Material hardness and ageing measurement using guided ultrasonic waves.

    PubMed

    Korde, Nilesh; Kundu, Tribikram

    2013-02-01

    Elastic properties of materials can be easily determined from the ultrasonic wave velocity measurement. However, material hardness cannot be obtained from the ultrasonic wave speed. Heat treatment and ageing affect the microstructure of many materials changing their hardness and strength. It has been already established that ultrasonic attenuation and dispersion are also affected by the material microstructure. It is investigated in this paper if the attenuation of ultrasonic guided waves can be correlated with the material ageing or duration of heat treatment and material hardness. To this aim six identical aluminum 2024 alloy plate specimens were subjected to different durations of heat treatment at 150°C and were inspected nondestructively propagating Lamb waves through the specimens. Attenuation of the Lamb wave was found to be inversely related to the hardness. Rockwell hardness test was performed to corroborate the ultrasonic observations. In comparison to the Rockwell hardness test the ultrasonic inspection was found to be more sensitive to the heat treatment duration and material ageing. From these results it is concluded that guided wave inspection method is a reliable and probably more desirable alternative for characterizing the hardness and microstructure of heat treated materials. Earlier investigations correlated the bulk wave attenuation with the material ageing while this work is the first attempt to correlate the guided wave attenuation to the material hardness and ageing. PMID:23047018

  4. Hardness Analysis. Training Module 5.215.2.77.

    ERIC Educational Resources Information Center

    Bonte, John L.; Davidson, Arnold C.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with hardness analysis using the EDTA method and the calculation of hardness given metal ion concentrations and a factor table. Included are objectives, an instructor guide, student handouts, and transparency masters. A video tape is also…

  5. The Simplified Partial Digest Problem: Hardness and a Probabilistic Analysis

    E-print Network

    Pratt, Vaughan

    The Simplified Partial Digest Problem: Hardness and a Probabilistic Analysis Zoë Abrams1 and Ho site locations of the enzyme. Two common approaches are the Double Digest Problem and the Partial Digest Problem. The Double Digest Problem is known to be NP-Complete[4], but the hardness of the Partial

  6. Puroindolines: the molecular genetic basis of wheat grain hardness

    Microsoft Academic Search

    Craig F. Morris

    2002-01-01

    The variation in grain hardness is the single most important trait that determines end-use quality of wheat. Grain texture classification is based primarily on either the resistance of kernels to crushing or the particle size distribution of ground grain or flour. Recently, the molecular genetic basis of grain hardness has become known, and it is the focus of this review.

  7. A NEW MODEL FOR PERFORMANCE PREDICTION OF HARD ROCK TBMS.

    E-print Network

    Chapter 50 A NEW MODEL FOR PERFORMANCE PREDICTION OF HARD ROCK TBMS. By: Jamal Rostami1 and Levent ABSTRACT A new theoretical/empirical model has been developed for performance predic- tion of hard rock TBMs. The model uses information on the rock properties and cutting geometry to calculate TBM rate

  8. Network Booting versus hard disks: Costs and Implications

    Microsoft Academic Search

    John M. Ostrowick

    In the African context, it does not necessarily make sense to spend large amounts of money on proprietary computing solutions when low cost solutions exist. This paper explores the experiences we have had in our University implementing both network-booting and hard disk- booting Linux systems. Most Linux systems boot from hard disk. Our system, one of the few in the

  9. Employing the Hard-Core: Internal Organizational Effects.

    ERIC Educational Resources Information Center

    Champagne, J. E.; And Others

    This paper is presented with the hope that those studying or directly involved in the utilization of hard-core persons in employment may gain insights which may make their tasks easier and more productive. It is written in a readable and non-technical nature and integrates experiences of hard-core utilization with accepted organization theory.…

  10. Application research of EDBA algorithm for completing hard disk copy

    Microsoft Academic Search

    Wang Zhaohui; Wang Xingang; Liu Pingping

    2009-01-01

    With the rapid development of Linux, Ext2 file system gradually becomes the popular file system format. But in the network cluster, while copying Ext2 file system format to many hard disks, this operation will waste much more time relatively. By analyzing the data structure of Ext2 file system on the hard disk partition, and getting the effective data bitmap, put

  11. HARD RED SPRING WHEAT QUALITY REPORT: 2000/2001 CROP.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercially grown cultivars and experimental lines of hard red spring wheat were grown by breeders at cooperative experiment stations throughout the major spring wheat growing regions of the United States. Hard spring wheat was tested for kernel, milling, flour, dough, and baking quality. In 2000...

  12. Dough Rheology and Wet Milling of Hard Waxy Wheat Flours

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To realize the full potential of waxy wheat (Triticum aestivum L.), wet milling of waxy wheat flour to produce gluten and waxy wheat starch was investigated. Flours of six advanced lines of waxy hard wheats, one normal hard wheat (‘Karl 92’), and one partial waxy wheat (‘Trego’) were fractionated by...

  13. Respiratory effects of hard-metal dust exposure

    SciTech Connect

    Balmes, J.R.

    1987-04-01

    Workers exposed to hard-metal dust are at risk of developing interstitial pulmonary fibrosis. Focusing on the lung parenchymal disorders that result, the author thoroughly reviews the background of the problem, animal studies and recent environmental data related to hard-metal disease, the clinical presentation, and finally its etiology.

  14. Performance of the Swellex bolt in hard and soft rocks

    Microsoft Academic Search

    C. Li; U. Håkansson

    In general Swellex bolts strengthen the rock mass through a combination of friction and mechanical interlock at the rock-bolt interface. The anchoring mechanism of the Swellex bolt is actually different in hard and soft rocks. In hard rock, the secondary contact stress, induced by the mechanical interlock of the asperities at the borehole wall, plays a major role in the

  15. Viscosity, hard sphere diameter and interionic potential for liquid lead

    E-print Network

    Boyer, Edmond

    L-347 Viscosity, hard sphere diameter and interionic potential for liquid lead G. Chaussemy The Macedo-Litovitz equation for a hard sphere liquid provides a satisfactory model for the viscosity of lead and molecular dynamics. The activation energy for viscosity (0.07 eV) is similar to the height of the interionic

  16. Set Cover Revisited: Hypergraph Cover with Hard Barna Saha1

    E-print Network

    Khuller, Samir

    Set Cover Revisited: Hypergraph Cover with Hard Capacities Barna Saha1 and Samir Khuller2 1 AT capacities. In the hard capacitated set cover problem, addi- tionally each set has a covering capacity which we are not allowed to exceed. In other words, after picking a set, we may cover at most a specified

  17. Young modulus dependence of nanoscopic friction coefficient in hard coatings

    E-print Network

    Brune, Harald

    Young modulus dependence of nanoscopic friction coefficient in hard coatings Elisa Riedoa, it is intuitive that a more compliant material, into which the AFM tip is likely to penetrate deeper, yields in industry as hard coatings.2,11 We demonstrate that the variations of the fric- tion coefficient in Cr

  18. Algorithms for Dependable Hard Real-Time Systems (Extended Abstract)

    E-print Network

    Algorithms for Dependable Hard Real-Time Systems £ (Extended Abstract) Peter Puschner Institut f of traditional coding and yields code that is well-suited for hard real-time systems, i.e., its WCET is short that are imposed on non real-time respectively real-time code are usu- ally quite diverse. In a system that does

  19. Hard and soft constraints for reasoning about qualitative conditional preferences

    E-print Network

    Rossi, Francesca

    Hard and soft constraints for reasoning about qualitative conditional preferences C. Domshlak1 , S problems are defined in terms of both hard and soft constraints, and qualitative conditional preferences- formation. In this paper we study how to exploit classical and soft constraint solvers for handling

  20. SOFT AND HARD ELASTICITY OF LIQUID CRYSTAL ELASTOMERS

    E-print Network

    #12;SOFT AND HARD ELASTICITY OF LIQUID CRYSTAL ELASTOMERS #12;#12;SOFT AND HARD ELASTICITY Model of liquid crystal elastomers 16 1.6 Soft Elasticity 18 1.7 Hints of complexity - stripe domains 22 Model 28 2.2 Predictions and successes of compositional fluctuations 29 2.3 Models of semi-softness 33 2

  1. Hardness of the Covering Radius Problem on Lattices

    Microsoft Academic Search

    Ishay Haviv; Oded Regev

    2006-01-01

    We provide the first hardness result for the Covering Radius P roblem on lattices (CRP). Namely, we show that for any large enough p ? 1 there exists a constant cp > 1 such that CRP in thep norm is ?2-hard to approximate to within any constant less than cp. In particular, for the case p = 1, we obtain

  2. Hardness measurement at penetration depths as small as 20 nm

    Microsoft Academic Search

    J. B. Pethicai; R. Hutchings; W. C. Oliver

    1983-01-01

    In this paper we investigate the properties of indentation hardness on the sub-micrometre scale in nickel, gold and silicon. Indenter penetration depths as low as 20 nm are used. The area of the indents is determined by electron microscopy, and thus the Meyer hardness calculated. The indenter penetration is monitored continuously during loading and unloading. We show that indent areas,

  3. Locality and hard SAT-instances Klas Markstrom

    E-print Network

    Markström, Klas

    -instance based on Eulerian graphs which are aimed at being hard for resolution based SAT-solvers. We discuss some for the 2005 SAT solver competition, none of which could be solved by the competing solvers. In connectionLocality and hard SAT-instances Klas Markstr¨om Klas.Markstrom@math.umu.se Department

  4. Amphiphilic hard body mixtures Matthias Schmidt and Christian von Ferber

    E-print Network

    Ott, Albrecht

    Amphiphilic hard body mixtures Matthias Schmidt and Christian von Ferber Institut fu¨r Theoretische Received 16 June 2001; published 29 October 2001 In order to study ternary amphiphilic mixtures, we and amphiphilic particles, where the hydrophilic head is modeled as a hard sphere and the hydrophobic tail

  5. Experiments with Hard, Soft, and Hydrodynamically Interacting Spheres

    Microsoft Academic Search

    Maarten Arnold Rutgers

    1995-01-01

    This thesis presents research on colloidal suspensions of nearly identical spheres and shows that some very interesting phenomena take place while the inter-particle interactions are simple in nature. The work is divided into three areas which explore aspects of hydrodynamic and hard core and electrostatic repulsive interactions. In chapter two hard core interactions are singled out, as we verify the

  6. An audiovisual content recorder using a removable hard disk drive

    Microsoft Academic Search

    Yoshihiro Hori; Yuichi Kanai; Kenji Taima

    2010-01-01

    We have developed an audiovisual content recorder using a removable hard disk drive. Protection of digital content recorded on the removable medium is important. Besides a large capacity and a high speed, the hard disk drive has much better features than optical discs, one of which is intelligent enough to make bi-directional authentication in the system. This benefit realizes more

  7. Neural network control of a hard disc drive

    Microsoft Academic Search

    G. Herrmann; Shuzhi Sam Ge; Guoxiao Guo

    2002-01-01

    An adaptive neural network (NN) controller is applied to the voice-coil-motor (VCM)-actuator of a hard disc drive (HDD). The controller can track asymptotically a given demand trajectory while compensating robustly for bounded friction and bias forces. It is shown practically that this controller is a good candidate for a track seek\\/following controller in hard discs.

  8. Acceleration feedforward control against rotational disturbance in hard disk drives

    Microsoft Academic Search

    Akihide Jinzenji; Tatsuro Sasamoto; Koichi Aikawa; Susumu Yoshida; Keiji Aruga

    2001-01-01

    We have developed an acceleration feedforward control fur hard disk drives by using dual piezoelectric accelerometers. The dual accelerometers detect angular acceleration in the hard disk drive (HDD) and compensate for its negative effects. For optimum compensation we introduced the use of a phase compensation filter (PCF). Using this controller, the rejection capability against rotational disturbance is improved and HDD

  9. Hard Spring Wheat Variety Descriptions Resistance To2

    E-print Network

    Dyer, Bill

    ; S =susceptible; VS =very susceptible; NA = data not available. #12;2 Hard White Spring Wheat Descriptions1 Hard Spring Wheat Variety Descriptions Resistance To2 Quality Factors Straw Stem Leaf Foliar Head herbicide family. 2 R =resistant; MR =moderately resistant; M =intermediate; MS =moderately susceptible

  10. The Hard X-Ray Telescope Mission

    NASA Astrophysics Data System (ADS)

    Gorenstein, P.; Joensen, K.; Romaine, S.; Worrall, D.; Cameron, R.; Weisskopf, M.; Ramsey, B.; Bilbro, J.; Kroeger, R.; Gehrels, N.; Parsons, A.; Smither, R.; Christensen, F.; Citterio, O.; von Ballmoos, P.

    1995-12-01

    The Hard X-Ray Telescope (HXT) mission concept contains focusing telescopes that collectively, observe simultaneously from the ultraviolet to 100 keV and in several narrow bands extending to 1 MeV. In pointed observations HXT is expected to have an order of magnitude more sensitivity and much finer angular resolution in the 10 to 100 keV band than all current and currently planned future missions, and considerably more sensitivity for detecting narrow lines in the 100 keV to 1 MeV regime. The detectors are small, cooled arrays of relatively low mass with very good energy resolution and some polarization sensitivity. HXT contains two types of hard X-ray telescopes. One type, called the modular modular telescope (MMT) utilizes a novel type of multilayer coating and small graze angles to extend the regime of focusing to 100keV. There is a two stage imaging detector at each focus, a CCD for X-rays < 10 keV followed down stream by either a germanium strip array or cadmium zinc telluride array for 10-100 keV X-rays. The other type of telescope, called the Laue Crystal Telescope (LCT) is a single adjustable array of several hundred Ge crystals that focus by Laue scattering. Individual picomotors adjust the angle of each crystal to diffract photons of a fixed energy to the same point along the optic axis where they converge upon a movable array of cooled germanium detectors. The LCT will have high sensitivity for detecting narrow X-ray lines of known energy such as those expected from Type 1 supernova. The UV monitor is a three telescope system that provides coverage in the ultraviolet band for study of time correlated changes across the broad electromagnetic spectrum of an AGN such as are expected in ``reverberation'' models. A WWW page will be created as a public bulletin board. This work is supported by NASA grant NAG8-1194

  11. Distributions of partons at small x values

    NASA Astrophysics Data System (ADS)

    Ryskin, M. G.; Shuvaev, A. G.

    2014-07-01

    New data on diffraction and inelastic scattering processes obtained at the Large Hadron Collider (LHC) have been analyzed. The properties of interactions at very high energies have been studied. In this case, the behavior of cross sections and distributions of secondary particles are determined by distributions of partons (constituents of the initial proton) carrying only a small fraction x of the momentum of the initial protons. It has been shown that not only the radius of the interaction but also characteristic transverse momenta of particles k t increase with the energy. A model has been developed for the simultaneous description of soft (with low k t values) and hard (with the production of jets of particles with high k t values) interactions; this model provides a continuous smooth transition between them. The possibility of the measurement of the parton density for very small x values at the LHC has been considered. A method has been proposed for the determination and variation of a factorization scale specifying the dimension of the spatial region in which partons are detected in these measurements.

  12. Effect of cooling rate on microstructural formation and hardness of 30CrNi3Mo steel

    NASA Astrophysics Data System (ADS)

    Qiao, Z. X.; Liu, Y. C.; Yu, L. M.; Gao, Z. M.

    2009-06-01

    The variation of microstructural formation and the hardness of the 30CrNi3Mo steel were systematically explored as a function of applied cooling rates in the range of 1-500°C/min. According to the measured Rockwell hardness results, four characteristic stages could be separated as different ranges of cooling rates, which corresponds well with the microstructural evolution observed. With the applied cooling rate increasing, the transformed structure evolves from granular bainite, lower bainite, self-tempered martensite, to finally martensite without self-tempering. Among them, the self-tempered martensite, obtained in the transformed specimens cooled with rates of 25-80°C/min, exhibits the highest hardness values due to the precipitation of fine carbides within it.

  13. Compressibility and hardness of Co-based bulk metallic glass: A combined experimental and density functional theory study

    SciTech Connect

    Wang Jianfeng; Li Ran; Xu Tao; Li Yan; Liu Zengqian; Huang Lu; Hua Nengbin; Zhang Tao [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Xiao Ruijuan [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li Gong [Stat Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Li Yanchun [BSRF, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)

    2011-10-10

    An incompressible Co{sub 54}Ta{sub 11}B{sub 35} bulk metallic glass (BMG) was investigated using in situ high-pressure synchrotron diffraction and nanoindendation. The elastic constants were deduced from the experiments based on the isotropic model. The Vickers hardness was measured to be 17.1 GPa. The elastic moduli and hardness are the highest values known in BMGs. The theoretically calculated elastic properties by density-functional study were well consistent with experimental measurements. The analysis of charge density and bonding character indicates the covalent character of Co-B and B-B bonds, underlying the unusually high elastic modulus and hardness in this material.

  14. Spectral evolution of gamma-ray bursts detected by the SIGNE experiment. 1: Correlation between intensity and spectral hardness

    NASA Technical Reports Server (NTRS)

    Kargatis, Vincent E.; Liang, Edison P.; Hurley, Kevin C.; Barat, C.; Eveno, E.; Niel, M.

    1994-01-01

    We study the continuum spectral evolution of 16 gamma-ray bursts detected by the Franco-Soviet SIGNE experiment in 1981-1982 by fitting time resolved (0.5 s) spectra in count space with simple thermal bremsstrahlung and synchrotron models. We find that there is no single characteristic of spectral evolution: we see hard-to-soft, soft-to-hard, luminosity-hardness tracking, and chaotic evolution. We perform correlation studies between instantaneous burst intensity and spectral temperature for seven bursts. While we basically confirm the existence of a correlation between these variables as originally claimed by Golenetskii et al. (1983) we find higher values and a broader range of correlation indices.

  15. Spectral evolution of gamma-ray bursts detected by the SIGNE experiment. 1: Correlation between intensity and spectral hardness

    NASA Astrophysics Data System (ADS)

    Kargatis, Vincent E.; Liang, Edison P.; Hurley, Kevin C.; Barat, C.; Eveno, E.; Niel, M.

    1994-02-01

    We study the continuum spectral evolution of 16 gamma-ray bursts detected by the Franco-Soviet SIGNE experiment in 1981-1982 by fitting time resolved (0.5 s) spectra in count space with simple thermal bremsstrahlung and synchrotron models. We find that there is no single characteristic of spectral evolution: we see hard-to-soft, soft-to-hard, luminosity-hardness tracking, and chaotic evolution. We perform correlation studies between instantaneous burst intensity and spectral temperature for seven bursts. While we basically confirm the existence of a correlation between these variables as originally claimed by Golenetskii et al. (1983) we find higher values and a broader range of correlation indices.

  16. Correcting Penetration Data for Variations in Target Hardness

    NASA Astrophysics Data System (ADS)

    Bless, Stephan; Cazamias, James; Black, Michael

    2001-06-01

    The penetration of projectiles is significantly affected by target hardness. It often happens that corrections must be made for uncontrolled variations in target hardness, or that data sets on targets with different hardnesses must be compared with one another. It is quite difficult experimentally to isolate the effects of hardness on penetration. However, it is possible to derive correction factors by measuring the effects of changes of velocity on a given target. This is possible if one assumes that the penetration is a function of a non-dimensional number formed by dividing the velocity squared by the strength. Then a Taylor series expansion relates dirivatives of penetration with respect to hardness to derivatives of penetration with respect to velocity. Examples for tungsten penetrating steel are provided.

  17. Hard-disk actuators for mini-teleoperation

    NASA Astrophysics Data System (ADS)

    Buttolo, Pietro; Hwang, Dal-Yeon; Marbot, Pierre-Henry; Hannaford, Blake

    1995-12-01

    Hard disk drives have evolved rapidly with computer miniaturization into highly compact and integrated electromechanical systems. Hard drives contain many precision mechanical parts which may prove useful in the design of small precision robots. The advantages of parts taken from hard disks include low cost, miniaturization, high quality, and for some applications, cleanliness. We report the results of engineering tests on flat coil head positioning actuators taken from hard drives of sizes ranging from 5.25' to 1.8' media diameter. We also perform a simple analysis which suggests that requirements for torque per unit mass are lower for small robot arms. The results suggest ways that hard disk actuators can be utilized in mini robotic designs and points the way towards improved versions of these designs for robotic purposes.

  18. Evaluation of Light Curing Distance and Mylar Strips Color on Surface Hardness of Two Different Dental Composite Resins

    PubMed Central

    Mousavinasab, Seyed Mostafa; Barekatain, Mehrdad; Sadeghi, Elahe; Nourbakhshian, Farzaneh; Davoudi, Amin

    2014-01-01

    Introduction: Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). Materials and methods: 40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05. Results: MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm2) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm2) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01). Conclusion: The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90. PMID:25228939

  19. Computational Modeling Develops Ultra-Hard Steel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

  20. Hard ticks (Acari, Ixodidae) of Croatia

    PubMed Central

    Kr?mar, Stjepan

    2012-01-01

    Abstract The present paper is based on original and literature data. In Croatia the first studies on the occurrence of ixodid species were made about 80 years ago. The number of tick species recorded in Croatia considerably increased during the 1950s, 60s, 70s and 80s of the past century. A total of 21 species of hard tick belonging to 5 genera have been recorded in Croatia. Ixodes is the best represented genus, with seven species recorded. Haemaphysalis is represented by six species, followed by Rhipicephalus with four species. Dermacentor and Hyalomma are represented by two species each. The ticks were collected on 47 different host species. Eleven tick species were collected on Bos taurus and Ovis aries, followed by Capra hircus and Equus caballus with 8 species and Canis lupus familiaris with 6 species. On the remaining 42 host species one, two or three tick species were collected. The most widespread tick is Ixodes ricinus which was found on 25 different host species. PMID:23372407

  1. The Hard X ray Telescope Mission

    NASA Technical Reports Server (NTRS)

    Gorenstein, Paul

    1997-01-01

    The Hard X Ray Telescope (HXT) was selected for study as a possible new intermediate size mission for the early 21st century. Its principal attributes are: (1) multiwavelength observing with a system of focussing telescopes that collectively observe from the UV to over 1 MeV, (2) much higher sensitivity and much better angular resolution in the 10100 keV band, and (3) higher sensitivity for detecting gamma ray lines of known energy in the 100 keV to 1 MeV band. The institutions collaborating in the study are: Smithsonian Astrophysical Observatory, Marshall Space Flight Center, Naval Research Laboratory, Goddard Space Flight Center, Argonne National Laboratory, Danish Space Research Institute, Osservatorio Astronomica di Brera (Merate), and Centre d'Etudes Spatiale des Rayonnements (Toulouse). The instrumentation includes several grazing incidence double conical telescopes with multilayer coatings that focus up to 100 keV and a single Laue crystal telescope that functions to 1 MeV. The detectors are CCDs, and germanium, and/or CdZnTe position sensitive arrays.

  2. Phase behavior of parallel hard cylinders.

    PubMed

    Capitán, José A; Martínez-Ratón, Yuri; Cuesta, José A

    2008-05-21

    We test the performance of a recently proposed fundamental measure density functional of aligned hard cylinders by calculating the phase diagram of a monodisperse fluid of these particles. We consider all possible liquid-crystalline symmetries, namely, nematic, smectic, and columnar, as well as the crystalline phase. For this purpose we introduce a Gaussian parametrization of the density profile and use it to numerically minimize the functional. We also determine, from the analytic expression for the structure factor of the uniform fluid, the bifurcation points from the nematic to the smectic and columnar phases. The equation of state, as obtained from functional minimization, is compared to the available Monte Carlo simulation. The agreement is very good, nearly perfect in the description of the inhomogeneous phases. The columnar phase is found to be metastable with respect to the smectic or crystal phases, its free energy though being very close to that of the stable phases. This result justifies the observation of a window of stability of the columnar phase in some simulations, which disappears as the size of the system increases. The only important deviation between theory and simulations shows up in the location of the nematic-smectic transition. This is the common drawback of any fundamental measure functional of describing the uniform phase just with the accuracy of scaled particle theory. PMID:18500895

  3. Global Value Trees

    PubMed Central

    Zhu, Zhen; Puliga, Michelangelo; Cerina, Federica; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    The fragmentation of production across countries has become an important feature of the globalization in recent decades and is often conceptualized by the term “global value chains” (GVCs). When empirically investigating the GVCs, previous studies are mainly interested in knowing how global the GVCs are rather than how the GVCs look like. From a complex networks perspective, we use the World Input-Output Database (WIOD) to study the evolution of the global production system. We find that the industry-level GVCs are indeed not chain-like but are better characterized by the tree topology. Hence, we compute the global value trees (GVTs) for all the industries available in the WIOD. Moreover, we compute an industry importance measure based on the GVTs and compare it with other network centrality measures. Finally, we discuss some future applications of the GVTs. PMID:25978067

  4. Bivariate extreme value distributions

    NASA Technical Reports Server (NTRS)

    Elshamy, M.

    1992-01-01

    In certain engineering applications, such as those occurring in the analyses of ascent structural loads for the Space Transportation System (STS), some of the load variables have a lower bound of zero. Thus, the need for practical models of bivariate extreme value probability distribution functions with lower limits was identified. We discuss the Gumbel models and present practical forms of bivariate extreme probability distributions of Weibull and Frechet types with two parameters. Bivariate extreme value probability distribution functions can be expressed in terms of the marginal extremel distributions and a 'dependence' function subject to certain analytical conditions. Properties of such bivariate extreme distributions, sums and differences of paired extremals, as well as the corresponding forms of conditional distributions, are discussed. Practical estimation techniques are also given.

  5. Starch granule size distribution of hard red winter and hard red spring wheat: Its effects on mixing and breadmaking quality.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch was isolated from 98 hard red winter (HRW) wheat and 99 hard red spring (HRS) wheat. Granule size/volume distributions of the isolated starches were analyzed using a laser diffraction particle size analyzer. There were significant differences in the size distribution between HRW and HRS whe...

  6. J.M. Carroll -"Soft versus hard: The essential tension?" 1 Soft versus Hard: The essential tension

    E-print Network

    Carroll, John M.

    J.M. Carroll - "Soft versus hard: The essential tension?" 1 Soft versus Hard: The essential tension some of its intelligibility to contemporary reading. However, I think it is worth recalling from this debate. What is HCI? Through the past 30 years, human-computer interaction has developed

  7. Complex-valued autoencoders.

    PubMed

    Baldi, Pierre; Lu, Zhiqin

    2012-09-01

    Autoencoders are unsupervised machine learning circuits, with typically one hidden layer, whose learning goal is to minimize an average distortion measure between inputs and outputs. Linear autoencoders correspond to the special case where only linear transformations between visible and hidden variables are used. While linear autoencoders can be defined over any field, only real-valued linear autoencoders have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the L(2) norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalization properties of the trained autoencoders, and can equally be applied to the hetero-associative case when external targets are provided. Partial results on deep architecture as well as the differential geometry of autoencoders are also presented. The general framework described here is useful to classify autoencoders and identify general properties that ought to be investigated for each class, illuminating some of the connections between autoencoders, unsupervised learning, clustering, Hebbian learning, and information theory. PMID:22622264

  8. Potential, Value, and Consistency

    Microsoft Academic Search

    Sergiu Hart; Andreu Mas-Colell

    1989-01-01

    Let P be a real-valued function defined on the space of cooperative games with transferable utility, satisfying the following condition: In every game, the marginal contributions of all players (according to P) are efficient (i.e., add up to the worth of the grand coalition). It is proved that there exists just one such function P--called the potential--and moreover that the

  9. The structure of value.

    PubMed

    Daly, Rich

    2014-01-01

    Keys to success in developing the right framework for delivering greater value in an era of reform include the following: Have a compelling vision. In evaluating potential partnerships, carefully consider the extent to which the organizations' cultures are aligned. Ensure that initiatives stay on course. Develop sustainable energy among leaders and staff through early wins. Measure patient, physician, and employee satisfaction before and after initiatives are implemented and respond accordingly. PMID:24511778

  10. Complex-Valued Autoencoders

    PubMed Central

    Baldi, Pierre; Lu, Zhiqin

    2012-01-01

    Autoencoders are unsupervised machine learning circuits, with typically one hidden layer, whose learning goal is to minimize an average distortion measure between inputs and outputs. Linear autoencoders correspond to the special case where only linear transformations between visible and hidden variables are used. While linear autoencoders can be defined over any field, only real-valued linear autoencoders have been studied so far. Here we study complex-valued linear autoencoders where the components of the training vectors and adjustable matrices are defined over the complex field with the L2 norm. We provide simpler and more general proofs that unify the real-valued and complex-valued cases, showing that in both cases the landscape of the error function is invariant under certain groups of transformations. The landscape has no local minima, a family of global minima associated with Principal Component Analysis, and many families of saddle points associated with orthogonal projections onto sub-space spanned by sub-optimal subsets of eigenvectors of the covariance matrix. The theory yields several iterative, convergent, learning algorithms, a clear understanding of the generalization properties of the trained autoencoders, and can equally be applied to the hetero-associative case when external targets are provided. Partial results on deep architecture as well as the differential geometry of autoencoders are also presented. The general framework described here is useful to classify autoencoders and identify general properties that ought to be investigated for each class, illuminating some of the connections between autoencoders, unsupervised learning, clustering, Hebbian learning, and information theory. PMID:22622264

  11. Minimum Critical Values Study

    SciTech Connect

    Fox, P.B.

    2005-07-11

    This report provides minimum critical values for various 30-cm water-reflected uranium and plutonium oxide and nitrate aqueous mixtures as calculated by the SCALE CSAS1X sequence using the 238-group ENDF/B-V neutron cross-section library. The minimum values were determined through parametric searches in one-dimensional geometry. The calculations have been performed to obtain the minimum values: critical volume and mass for spheres, critical radius for cylinders, critical thickness for slabs, and minimum critical concentration (infinite geometry) for the following homogeneous mixtures: (1) UO{sub 2}-H{sub 2}O for 3, 4, 5, 20, and 100 wt % {sup 235}U; (2) UNH for 3, 4, 5, 20, and 100 wt % {sup 235}U; (3) PuO{sub 2}-H{sub 2}O for 100/0/0, 95/5/0, 90/5/5, 80/10/10, and 71/17/11/1 wt % of {sup 239}Pu/{sup 240}Pu/{sup 241}Pu(/{sup 242}Pu); and (4) PuNH for 100/0/0, 95/5/0, 90/5/5, 80/10/10, and 71/17/11/1 wt % of {sup 239}Pu/{sup 240}Pu/{sup 241}Pu(/{sup 242}Pu). All bounding surfaces were fully reflected by 30 cm of H{sub 2}O.

  12. Estimation of calcified tissues hardness via calcium and magnesium ionic to atomic line intensity ratio in laser induced breakdown spectra

    NASA Astrophysics Data System (ADS)

    Abdel-Salam, Z. A.; Galmed, A. H.; Tognoni, E.; Harith, M. A.

    2007-12-01

    Calcified tissues representing three different matrices, namely enamel of human teeth, shells and eggshell, have been studied via Laser Induced Breakdown Spectroscopy (LIBS) technique. The experimental CaII/CaI and MgII/MgI ratios have been measured, in view of the expected correlation between the extent of ionization caused by the laser induced shock wave (SW) and the hardness of the target. The ratio CaII/CaI between the ionic calcium line at 373.69 nm and the neutral line at 428.9 nm is obtained for enamel, shells and eggshell spectra, as well as the ratio MgII/MgI between the ionic magnesium line at 280.26 nm and the neutral line at 285.22 nm. The results show that such spectral lines intensities ratio differs for different matrices and is indeed related to the target materials hardness. It is also found that the MgII/MgI ratio is preferable as an indicator of hardness since these lines are less affected by self absorption. The SW front speed has been measured in the three cases and the obtained values confirm the proportionality to the target hardness. The results here obtained suggest the feasibility of the quantitative estimation of hardness for any other calcified tissues.

  13. Chromium nitride-silver self-lubricating nanoporous hard coatings

    NASA Astrophysics Data System (ADS)

    Mulligan Christopher P

    The focus of this thesis research is to explore a new approach to adaptive solid lubrication using nanoporous hard coatings. To investigate this approach, I deposited prototype coatings for study consisting of a hard chromium nitride (CrN) matrix co-deposited with a lubricious silver (Ag) phase by reactive magnetron co-sputtering. The idea is to exploit the relative immiscibility of the two phases to create nanocomposite structures with intrinsic lubricant transport properties enabled by the presence of the nanopores. Specifically, I develop the scientific understanding of the critical growth parameters that govern nanocomposite structural evolution which in turn control mechanical properties, solid lubricant diffusion, and tribological response. Mechanical properties were analyzed by both micro and nanoindentation measurements for the composites as a function of Ag aggregate morphology. For Ts ? 500°C, hardness as measured by nanoindentation into the surface is relatively uniform giving values of 14.6, 13.6, and 14.3 GPa for Ts = 300, 400, and 500°C respectively. For Ts > 500°C, the cross-sectional microhardness increases with T s from 16.5 to 19.7 to 24.3 GPa for Ts = 500, 600, and 700°C, respectively, which is attributed to a decrease in the effective Ag concentration associated with temperature activated segregation. The average hardness for pure CrN samples is 23.8 and 27.5 GPa as measured by surface nanoindentation and cross-sectional microindentation, respectively. Lubricant transport behavior was characterized by a series of vacuum annealing experiments. Vacuum annealing experiments at Ta = 425, 525, and 625°C show that Ag diffuses to the coating surface to form lubricious surface aggregates and that the rate for Ag lubricant transport increases with increasing DeltaT (Ta - Ts) for Ta > Ts, as determined by quantitative electron microscopy surface analyses. However, the Ag remains in the CrN matrix for Ta < Ts, which is attributed to the Ag aggregate size distribution within the coating which affects the chemical potential. Friction and wear behavior were measured in ambient air at test temperatures, Tt = 20°C to 700°C to study the self-lubricating properties and tribological mechanisms of the coatings as a function of structure and lubricant transport properties. Ball-on-disk tribological tests against 100Cr6 steel at Tt = 20°C indicate that the Ag grains for Ts = 500°C are too small to facilitate an effective lubricious surface layer, resulting in a friction coefficient micro = 0.58 and a composite coating wear rate of 3.8x10-6 mm3/Nm that are nearly identical to those measured for pure CrN with micro = 0.64 and 3.6x10-6 mm3/Nm. The Ts = 600°C coating exhibits a 15% higher Ag concentration on the surface of the wear track than outside the wear track which acts as a lubricious layer that reduces micro to 0.47 and yields a 16x and 2.4x lower wear rate for coating and counterface, respectively. Replacing the steel counterface with an alumina ball results in the lowest micro = 0.50 for Ts = 500°C, attributed to the presence of Ag and the relatively low hardness of 16.5 GPa for this particular coating. High temperature tribological response during ball-on-disk sliding in ambient air against alumina was found to depend strongly on both Ts and the testing temperature Tt = 450, 550, and 650°C. At Tt < Ts, the friction coefficient micro = 0.31--0.34, which is 25--35% below pure CrN with micro = 0.45. This moderate lubrication improvement is attributed to the presence of lubricious Ag within the CrN matrix. In contrast, Tt > Ts results in Ag lubricant transport to the coating surface and the formation of an effective self-lubricating layer, reducing the friction up to 65% to micro = 0.16--0.24. However, raising Tt well above Ts causes relatively rapid lubricant transport to the surface, followed by Ag depletion which results in a short low micro regime followed by a rapid rise in micro and often mechanical collapse of the matrix. The measured wear rate also strongly depends on the Ag sol

  14. Hard-Earned Income and Tax Compliance

    Microsoft Academic Search

    Stephan Muehlbacher; Erich Kirchler; Erik Hoelzl; Julie Ashby; Chiara Berti; Jenny Job; Simon Kemp; Ursula Peterlik; Christine Roland-lévy; Karin Waldherr

    Abstract. Is the effort invested to achieve taxable income,a relevant factor for tax compliance? If the value of income increases with the effort exerted, reluctance to pay taxes should be high. On the other hand, if income is perceived as compensation for one’s endeavor, there is too much at stake to take the risk of being audited and paying a

  15. The Coma Cluster hard X-ray spectrum revisited: still no evidence for a hard tail

    E-print Network

    M. Rossetti; S. Molendi

    2007-02-15

    In this note, we reply to Fusco-Femiano et al. (2004) and Fusco-Femiano et al. (2006), who cast doubts on our analysis of the PDS observations of the Coma Cluster which we describe in Rossetti & Molendi (2004). We discuss the main issues in Fusco-Femiano et al. (2006) and we confirm that the available data do not allow to firmly establish the presence of a non-thermal component in the hard X-ray spectrum of the Coma cluster.

  16. Low hardness organisms: Culture methods, sensitivities, and practical applications

    SciTech Connect

    DaCruz, A.; DaCruz, N.; Bird, M.

    1995-12-31

    EPA Regulations require biomonitoring of permitted effluent and stormwater runoff. Several permit locations were studied, in Virginia, that have supply water and or stormwater runoff which ranges in hardness from 5--30 mg/L. Ceriodaphnia dubia (dubia) and Pimephales promelas (fathead minnow) were tested in reconstituted water with hardnesses from 5--30 mg/L. Results indicated osmotic stresses present in the acute tests with the fathead minnow as well as chronic tests for the dubia and the fathead minnow. Culture methods were developed for both organism types in soft (30 mg) reconstituted freshwater. Reproductivity and development for each organisms type meets or exceeds EPA testing requirements for moderately hard organisms. Sensitivities were measured over an 18 month interval using cadmium chloride as a reference toxicant. Additionally, sensitivities were charted in contrast with those of organisms cultured in moderately hard water. The comparison proved that the sensitivities of both the dubia and the fathead minnow cultured in 30 mg water increased, but were within two standard deviations of the organism sensitivities of those cultured in moderately hard water. Latitude for use of organisms cultured in 30 mg was documented for waters ranging in hardness from 10--100 mg/L with no acclimation period required. The stability of the organism sensitivity was also validated. The application was most helpful in stormwater runoff and in effluents where the hardness was 30 mg/L or less.

  17. Single-valued periods and multiple zeta values

    E-print Network

    Francis Brown

    2013-09-20

    The values at 1 of single-valued multiple polylogarithms span a certain subalgebra of multiple zeta values. In this paper, the properties of this algebra are studied from the point of view of motivic periods.

  18. Reliability of hard plastic clad silica fibers

    NASA Astrophysics Data System (ADS)

    Skutnik, Bolesh J.; Spaniol, Stefan

    2006-04-01

    New formulations of cladding materials have become available in recent times for Hard Plastic Clad Silica (HPCS) fibers, Initial data showed gains in some properties, particularly dynamic strength, especially for high numerical aperture (NA) fibers. A systematic study has been undertaken to determine the full strength and fatigue behavior of these HPCS fibers and to make comparisons to earlier HPCS fibers. Preliminary results, now confirmed, has shown improved median dynamic strength and higher Weibull slope. Full results are presented below including fatigue behavior and optical properties. These fibers have many applications and benefits in the high power delivery and medical laser uses as highlighted below. High power diode laser systems with their laser diode bars and arrays not only require special fibers to couple directly to the diode emitters, but also require special fibers to couple from the laser to application sites. These latter power delivery fibers are much larger than the internal fibers but still must be flexible, and have not only good strength but also good fatigue behavior. This particularly important industrial systems using robotic arms to apply the high power laser energy at a treatment site. The optical properties of HPCS fibers are well suited for the needs of the delivery of high power from diode laser bars and arrays to an application site. Benefits of strong median dynamic strengths and tighter flaw distributions in such cases will be discussed. Many medical applications, especially endoscopic ones, can benefit from the use of highly flexible, high NA, cost effective, HPCS optical fibers. Benefits of high strength and good fatigue behavior for such fibers in endoscopic procedures, including laser surgery, are discussed briefly including implications for mechanical reliability in medical and industrial settings.

  19. Parents welcome "hard-hitting" campaign.

    PubMed

    1994-01-01

    The FPA (Family Planning Association)'s recent pilot campaign to encourage parents to talk to their children about sex has generated an excellent response rate. Funded by the Department of Health as part of "The health of the nation" efforts to reduce unplanned teenage pregnancies, the campaign centered on two radio advertisements. Aired during March in Greater London and North West England, the advertisements featured a free phone number from which people could obtain free copies of the booklet "Answering your child's questions," part of the FPA's "Growing Up" series. Nearly 7500 copies of the booklet were distributed in response to over 5000 requests--2500 rang in the first week alone. Most requests were from parents (69% mothers, 31% fathers) with one to three children aged between 7 and 13. Over 1000 requests were from parents with children under 7. Hundreds of schools, youth clubs, health professionals and voluntary organizations requested multiple booklets for use in their work. Research carried out to gauge public reaction showed overwhelming support for the campaign's message, demonstrating the immense need by parents for information in this area. "Answering your child's questions" was praised for being "open, direct and easy to follow." One parent said, "The booklet arms parents with the right way of putting information across." Parents described the advertisements as "hard-hitting" and "attention-grabbing." One listener commented: "They really stopped me in my tracks." FPA director Doreen Massey said: "The favorable reaction to the campaign is extremely encouraging. We are looking at ways to relay this pilot effort into a full-scale UK-wide campaign next year." PMID:12287880

  20. High efficiency, radiation-hard solar cells

    SciTech Connect

    Ager III, J.W.; Walukiewicz, W.

    2004-10-22

    The direct gap of the In{sub 1-x}Ga{sub x}N alloy system extends continuously from InN (0.7 eV, in the near IR) to GaN (3.4 eV, in the mid-ultraviolet). This opens the intriguing possibility of using this single ternary alloy system in single or multi-junction (MJ) solar cells of the type used for space-based surveillance satellites. To evaluate the suitability of In{sub 1-x}Ga{sub x}N as a material for space applications, high quality thin films were grown with molecular beam epitaxy and extensive damage testing with electron, proton, and alpha particle radiation was performed. Using the room temperature photoluminescence intensity as a indirect measure of minority carrier lifetime, it is shown that In{sub 1-x}Ga{sub x}N retains its optoelectronic properties at radiation damage doses at least 2 orders of magnitude higher than the damage thresholds of the materials (GaAs and GaInP) currently used in high efficiency MJ cells. This indicates that the In{sub 1-x}Ga{sub x}N is well-suited for the future development of ultra radiation-hard optoelectronics. Critical issues affecting development of solar cells using this material system were addressed. The presence of an electron-rich surface layer in InN and In{sub 1-x}Ga{sub x}N (0 < x < 0.63) was investigated; it was shown that this is a less significant effect at large x. Evidence of p-type activity below the surface in Mg-doped InN was obtained; this is a significant step toward achieving photovoltaic action and, ultimately, a solar cell using this material.

  1. The European Values Study

    NSDL National Science Digital Library

    Curious minds want to know: "What exactly do Europeans believe?" It's an important and interesting question, and the directors and researchers in charge of the European Values Study (EVS) have been looking into this subject since the early 1980s. Based in the Netherlands the EVS concerns itself with asking Europeans about religion and morality, politics, work and leisure, and relationships. On their homepage, visitors can learn about their work and view previous and current surveys. While visitors do not have access to the raw data on the site, they can look at the questionnaires and read publications based on this research.

  2. Earned Value-Added

    NASA Technical Reports Server (NTRS)

    Jansen, Michael

    2005-01-01

    Earned value management [EVM] ...either you swear by it, or swear at it. Either way, there s no getting around the fact that EVM can be one of the most efficient and insightful methods of synthesizing cost, schedule, and technical status information into a single set of program health metrics. Is there a way of implementing EVM that allows a program to reap its early warning benefits while avoiding the pitfalls that make it infamous to its detractors? That s the question recently faced by the International Space Station [ISS] program.

  3. Non-effect of water hardness on the accumulation and toxicity of copper in a freshwater macrophyte (Ceratophyllum demersum): how useful are hardness-modified copper guidelines for protecting freshwater biota?

    PubMed

    Markich, Scott J; King, Angus R; Wilson, Scott P

    2006-12-01

    Several nations have adopted hardness-modified copper (Cu) guidelines for protecting freshwater biota. However, there is a lack of good quality data and mechanistic understanding on the effects of true water hardness (calcium (Ca) and magnesium (Mg)) on the bioavailability and toxicity of Cu to freshwater biota, particularly macrophytes. This study determined the effect of true water hardness (35, 90 and 335 mg CaCO(3)/l, added as Ca and Mg chloride in a 1:1 mole ratio) on the cell surface binding affinity (log K), accumulation and toxicity (96 h growth (biomass and stem length) and photosynthetic pigment inhibition) of Cu in the free-floating submerged macrophyte, Ceratophyllum demersum, in a synthetic freshwater with constant alkalinity (16 mg CaCO(3)/l) and pH (7.0). There were no significant (P>0.05) differences in the cell surface binding affinity, accumulation or toxicity of Cu in C. demersum with a 10-fold increase in water hardness from 35 to 335 mg CaCO(3)/l. The mean 96 h EC(50) values (and 95% confidence intervals) for biomass, the most sensitive endpoint, were 8.4 (7.6-9.2), 8.9 (8.0-9.8) and 9.9 (9.1-10.7) microg/l Cu for 35, 90 and 335 mg CaCO(3)/l, respectively. Speciation calculations indicated only very small (1-6%) differences in the percentage distribution (i.e. bioavailability) of Cu over the hardness range. These collective results indicate no apparent competition between Cu and Ca/Mg for binding sites on the cell surface. Given that the mechanism of Cu uptake (via Cu-specific and Na-linked transporters) is fundamentally different to that of Cd, Ni, Pb and Zn (via Ca transporters), for which other hardness-dependent algorithms have been developed, it is doubtful whether a hardness-modified Cu guideline value will be sufficiently protective of sensitive freshwater biota, such as C. demersum, particularly in medium-hard fresh surface waters with low levels of dissolved organic carbon. The biotic ligand model offers a more flexible and mechanistic approach for deriving site-specific Cu (metal) guidelines for protecting freshwater biota. PMID:16735056

  4. value name , x integer literal

    E-print Network

    Sewell, Peter

    value name , x ident integer literal index , i , j , n, m typeconstr ::= | unit | bool | int typvar ( # , t ) M constant , c ::= | integer literal | false | true | () | (&&) | not expr , e ::= | value name | constant | expr expr # | function value name # expr bind value name in expr | let value name = expr in expr

  5. Evaluation of the Efficiency and Effectiveness of Three Minimally Invasive Methods of Caries Removal: An in vitro Study

    PubMed Central

    Manjula, M; Reddy, E Rajendra; Srilaxmi, N; Rani, Tabitha

    2014-01-01

    ABSTRACT Background: Many chemomechanical caries removal (CMCR) agents have been introduced and marketed since 1970s, with each new one being better and effective than the previously introduced. Papacarie and Carisolv are new systems in the field of CMCR techniques. These are reportedly minimally invasive methods of removing carious dentin while preserving sound dentin. Aim: To compare the Efficiency (time taken for caries removal) and effectiveness (Knoop hardness number of the remaining dentin) of caries removal by three minimally invasive methods, i.e. hand excavation and chemomechanical caries removal using Carisolv and Papacarie. Materials and methods: Thirty recently extracted human permanent molars with occlusal carious lesions were divided randomly in three equal groups and bisected through the middle of the lesion mesiodistally and excavated by two methods on each tooth. Results: Statistically significant difference was present among three methods with respect to time and knoop hardness values (KHN) of the remaining dentin. Conclusion: The Efficiency of Hand method is better compared to CMCR techniques and effectiveness of CMCR techniques is better than Hand method in terms of dentin preservation so the chances of maintaining vitality of the pulp will be enhanced. How to cite this article: Boob AR, Manjula M, Reddy ER, Srilaxmi N, Rani T. Evaluation of the Efficiency and Effectiveness of Three Minimally Invasive Methods of Caries Removal: An in vitro Study. Int J Clin Pediatr Dent 2014;7(1):11-18. PMID:25206231

  6. A soft-hard combination-based cooperative spectrum sensing scheme for cognitive radio networks.

    PubMed

    Do, Nhu Tri; An, Beongku

    2015-01-01

    In this paper we propose a soft-hard combination scheme, called SHC scheme, for cooperative spectrum sensing in cognitive radio networks. The SHC scheme deploys a cluster based network in which Likelihood Ratio Test (LRT)-based soft combination is applied at each cluster, and weighted decision fusion rule-based hard combination is utilized at the fusion center. The novelties of the SHC scheme are as follows: the structure of the SHC scheme reduces the complexity of cooperative detection which is an inherent limitation of soft combination schemes. By using the LRT, we can detect primary signals in a low signal-to-noise ratio regime (around an average of -15 dB). In addition, the computational complexity of the LRT is reduced since we derive the closed-form expression of the probability density function of LRT value. The SHC scheme also takes into account the different effects of large scale fading on different users in the wide area network. The simulation results show that the SHC scheme not only provides the better sensing performance compared to the conventional hard combination schemes, but also reduces sensing overhead in terms of reporting time compared to the conventional soft combination scheme using the LRT. PMID:25688589

  7. Study of Flux Ratio of C60 to Ar Cluster Ion for Hard DLC Film deposition

    SciTech Connect

    Miyauchi, K.; Toyoda, N.; Kanda, K.; Matsui, S. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Kitagawa, T. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Nomura Plating Co., Ltd., Nishiyodogawa, Osaka (Japan); Yamada, I. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Collaborative research center for cluster ion beam process technology (Japan)

    2003-08-26

    To study the influence of the flux ratio of C60 molecule to Ar cluster ion on (diamond like carbon) DLC film characteristics, DLC films deposited under various flux ratios were characterized with Raman spectrometry and Near Edge X-ray Absorption Fine Structure (NEXAFS). From results of these measurements, hard DLC films were deposited when the flux ratio of C60 to Ar cluster ion was between 0.7 and 4. Furthermore the DLC film with constant sp2 content was obtained in the range of the ratio from 0.7 to 4, which contents are lower values than that of conventional films such as RF plasma. DLC films deposited under the ratio from 1 to 4 had hardness from 40 to 45GPa. It was shown that DLC films with stable properties of low sp2 content and high hardness were formed even when the fluxes were varied from 1 to 4 during deposition. It was indicated that this process was useful in the view of industrial application.

  8. Orientational ordering in hard rectangles: The role of three-body correlations.

    PubMed

    Martínez-Ratón, Yuri; Velasco, Enrique; Mederos, Luis

    2006-07-01

    We investigate the effect of three-body correlations on the phase behavior of hard rectangle two-dimensional fluids. The third virial coefficient B3 is incorporated via an equation of state that recovers scaled particle theory for parallel hard rectangles. This coefficient, a functional of the orientational distribution function, is calculated by Monte Carlo integration, using an accurate parametrized distribution function, for various particle aspect ratios in the range of 1-25. A bifurcation analysis of the free energy calculated from the obtained equation of state is applied to find the isotropic (I)-uniaxial nematic (N(u)) and isotropic-tetratic nematic (N(t)) spinodals and to study the order of these phase transitions. We find that the relative stability of the N(t) phase with respect to the isotropic phase is enhanced by the introduction of B3. Finally, we have calculated the complete phase diagram using a variational procedure and compared the results with those obtained from scaled particle theory and with Monte Carlo simulations carried out for hard rectangles with various aspect ratios. The predictions of our proposed equation of state as regards the transition densities between the isotropic and orientationally ordered phases for small aspect ratios are in fair agreement with simulations. Also, the critical aspect ratio below which the N(t) phase becomes stable is predicted to increase due to three-body correlations, although the corresponding value is underestimated with respect to simulation. PMID:16863310

  9. Orientational ordering in hard rectangles: The role of three-body correlations

    NASA Astrophysics Data System (ADS)

    Martínez-Ratón, Yuri; Velasco, Enrique; Mederos, Luis

    2006-07-01

    We investigate the effect of three-body correlations on the phase behavior of hard rectangle two-dimensional fluids. The third virial coefficient B3 is incorporated via an equation of state that recovers scaled particle theory for parallel hard rectangles. This coefficient, a functional of the orientational distribution function, is calculated by Monte Carlo integration, using an accurate parametrized distribution function, for various particle aspect ratios in the range of 1-25. A bifurcation analysis of the free energy calculated from the obtained equation of state is applied to find the isotropic (I)-uniaxial nematic (Nu) and isotropic-tetratic nematic (Nt) spinodals and to study the order of these phase transitions. We find that the relative stability of the Nt phase with respect to the isotropic phase is enhanced by the introduction of B3. Finally, we have calculated the complete phase diagram using a variational procedure and compared the results with those obtained from scaled particle theory and with Monte Carlo simulations carried out for hard rectangles with various aspect ratios. The predictions of our proposed equation of state as regards the transition densities between the isotropic and orientationally ordered phases for small aspect ratios are in fair agreement with simulations. Also, the critical aspect ratio below which the Nt phase becomes stable is predicted to increase due to three-body correlations, although the corresponding value is underestimated with respect to simulation.

  10. Hard thermal effective actions in the Schwinger formulation

    SciTech Connect

    Das, Ashok [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0171 (United States); Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700064 (India); Frenkel, J. [Instituto de Fisica, Universidade de Sao Paulo, Sao Paulo, SP 05315-970 (Brazil)

    2007-01-15

    We derive the properties of hard thermal effective actions in gauge theories from the point of view of Schwinger's proper time formulation. This analysis is simplified by introducing a set of generalized energy and momenta which are conserved and are nonlocal in general. These constants of motion, which embody energy-momentum exchanges between the fields and the particles along their trajectories, can be related to a class of gauge invariant or covariant potentials in the hard thermal regime. We show that in this regime the generalized energy, which is nonlocal in general, generates the characteristic nonlocal behavior of the hard thermal effective actions.

  11. Effect of Rolling and Annealing on Hardness of Brass

    NSDL National Science Digital Library

    Cantrell, Andrew

    This lesson plan will provide an introduction to the hardness of materials. Specifically, the exercise will allow students the opportunity to "observe the changes in hardness of brass resulting from different percentages of rolling, along with the accompanying changes in microstructure." Students will also learn the differences between the hardness and strength of a material. The module would be best for upper level high school and college students, and should take one class period to complete. The document is available to download in PDF file format.

  12. Self-diffusion in liquid gallium and hard sphere model

    NASA Astrophysics Data System (ADS)

    Blagoveshchenskii, Nikolay; Novikov, Arkady; Puchkov, Alexander; Savostin, Vadim; Sobolev, Oleg

    2015-01-01

    Incoherent and coherent components of quasielastic neutron scattering have been studied in the temperature range of T = 313 K - 793 K aiming to explore the applicability limits of the hard-sphere approach for the microscopic dynamics of liquid gallium, which is usually considered as a non-hard-sphere system. It was found that the non-hard-sphere effects come into play at the distances shorter than the average interatomic distance. The longer range diffusive dynamics of liquid Ga is dominated by the repulsive forces between the atoms.

  13. Cr-based bulk metallic glasses with ultrahigh hardness

    NASA Astrophysics Data System (ADS)

    Si, J. J.; Wang, T.; Wu, Y. D.; Cai, Y. H.; Chen, X. H.; Wang, W. Y.; Liu, Z. K.; Hui, X. D.

    2015-06-01

    This letter reports quaternary Cr-Co-Nb-B bulk metallic glasses (BMGs) with ultrahigh hardness and Young's moduli. Especially, Cr55Co24Nb7B14 BMG exhibits ultrahigh Vickers hardness and Young's modulus of 1605 and 278 GPa, respectively, and the highest specific Young's modulus of 37.0 × 106 N m/kg among all the developed BMGs so far. It is considered that the high hardness and Young's moduli for this kind of BMGs are intrinsically attributed to the strong interactions between metallic constituent elements and B.

  14. Radiation hardness of lead glasses TF1 and TF101

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masaaki; Prokoshkin, Yuri; Singovsky, Alexandre; Takamatsu, Kunio

    1994-06-01

    We have measured the radiation hardness of two types of lead glasses, TF1 and TF101, for low energy ?-rays from 60Co. TF101 containing cerium is a few tens times radiation harder than TF1 which contains no cerium. The radiation hardness, or the tolerable accumulated dose, of TF101 is 2 × 10 3 rad when the degradation of the transmittance is required to be less than 1% for the unit radiation length X0 = 2.8 cm. When the present result is compared with the work of Inyakin et al., the radiation hardness of TF101 glass should be similar for both ?-rays and for high energy hadrons.

  15. Light energy transmission through composite influenced by material shades.

    PubMed

    Guiraldo, Ricardo Danil; Consani, Simonides; Consani, Rafael Leonardo Xediek; Berger, Sandrine Bittencourt; Mendes, Wilson Batista; Sinhoreti, Mario Alexandre Coelho

    2009-01-01

    This study investigated the influence of different composite resin shades on light energy transmission through the composite, hardness and cross-link density (CLD). The composite Filtek Z250 was used in shades A1, A2, A3, A3.5 and A4. A quartz tungsten halogen light curing unit was used at an irradiance of 900 mW/cm(2). Thirty specimens were made for each shade. Light energy transmission that passed through the composite was calculated (n=10). Differences in Knoop hardness between the top and bottom (DKH) of the same specimen were calculated (n=10). The Knoop hardness value for each surface was recorded as the average of three indentations (KHN(1)). Thereafter, the specimens were soaked in absolute ethanol for 24hr at room temperature, and hardness was again determined (KHN(2)). The CLD was estimated by the softening effect produced by ethanol, i.e., by decrease in hardness. The percentage of decrease in KHN(2) compared with KHN(1) (PD) in the same specimen was then calculated for both surfaces (n=10). The data were submitted to an ANOVA in different tests (Light energy transmission, Knoop hardness and CLD). The irradiance of light that passed through composite shade A1 (408 mW/cm(2)) was statistically greater than that through shade A2 (376 mW/cm(2)), and was greater through A2 than A3 (359 mW/cm(2)) and through A3 than A3.5 (327 mW/cm(2)); A3.5 showed no statistical difference when compared to A4 (324 mW/cm(2)). The DKH of A4 (20.56%) was not statistically higher than that of A3.5 (20.14%), which was greater than that of A3 (14.08%), A2 (11.65%) and A1 (9.06%). There was no statistical difference in CLD. Darker shades had a significant influence on light energy transmission through dental resin composite and its hardness. However, CLD was not affected by darker dental composite shades. PMID:20179393

  16. CollegeValues.org

    NSDL National Science Digital Library

    Supported by a grant from the John Templeton Foundation, CollegeValues.org is a website for the Journal of College and Character and the Character Clearninghouse, both of which are published by the Center for the Study of College Student Values. The Center itself is headed by Jon C. Dalton of Florida State University, and the primary intent of the site is "to examine how colleges and universities influence, both intentionally and unintentionally, the moral and civic learning and behaviors of college students." To that end, the site has a great deal of information about this rather intriguing (and controversial) subject, such as lists of college student creeds or covenants, listings of best college character programs, and a listing of international perspectives on the topic. One of the most fascinating aspects of the site are the Presidents' Public Diaries, which feature reflections from a number of college presidents on the ethical aspects of their leadership roles. The site is rounded out by the full-text editions of the Journal of College and Character (which features two volumes as of late), and includes pieces titled Spirituality and the Vitality of Academic Life, and Educating for Dissent as a Civic Responsibility.

  17. World Values Survey

    NSDL National Science Digital Library

    Started in 1981, the World Values Survey is an ambitious worldwide investigation of sociocultural and political change being conducted by an international network of social scientists at universities across the globe. Since its inception, a total of four waves of representative sample research have been conducted producing "evidence of gradual but pervasive changes in what people want out of life." The survey shows that the basic direction of these changes is, to some extent, predictable. Following from this intriguing (and perhaps contestable) thesis, the website provides access to a number of the publications that have been generated from the group's scholarship, along with information about ordering various monographs and other publications. Visitors can also view the various questionnaires used to sample the different population groups, and read news updates about their work. As mentioned, the site also allows visitors to download some of the most recent work done by the scholars at the World Values Survey, including papers dealing with democratic aspirations and ideals in East Asia and postmaterialism.

  18. Simulation of a hard-spherocylinder liquid crystal with the pe

    NASA Astrophysics Data System (ADS)

    Fischermeier, Ellen; Bartuschat, Dominik; Preclik, Tobias; Marechal, Matthieu; Mecke, Klaus

    2014-12-01

    The pe physics engine is validated through the simulation of a liquid crystal model system consisting of hard spherocylinders. For this purpose we evaluate several characteristic parameters of this system, namely the nematic order parameter, the pressure, and the Frank elastic constants. We compare these to the values reported in literature and find a very good agreement, which demonstrates that the pe physics engine can accurately treat such densely packed particle systems. Simultaneously we are able to examine the influence of finite size effects, especially on the evaluation of the Frank elastic constants, as we are far less restricted in system size than earlier simulations.

  19. Simulation of a Hard-Spherocylinder Liquid Crystal with the pe

    E-print Network

    Ellen Fischermeier; Dominik Bartuschat; Tobias Preclik; Matthieu Marechal; Klaus Mecke

    2014-10-21

    The pe physics engine is validated through the simulation of a liquid crystal model system consisting of hard spherocylinders. For this purpose we evaluate several characteristic parameters of this system, namely the nematic order parameter, the pressure, and the Frank elastic constants. We compare these to the values reported in literature and find a very good agreement, which demonstrates that the pe physics engine can accurately treat such densely packed particle systems. Simultaneously we are able to examine the influence of finite size effects, especially on the evaluation of the Frank elastic constants, as we are far less restricted in system size than earlier simulations.

  20. Phase separation of binary nonadditive hard sphere fluid mixture confined in random porous media

    NASA Astrophysics Data System (ADS)

    Chen, W.

    2013-10-01

    I analyze the fluid-fluid phase separation of nonadditive hard sphere fluid mixture absorbed in random porous media. An equation of state is derived by using the perturbation theory to this complex system with quenched disorders. The results of this theory are in good agreement with those obtained from semi-grand canonical ensemble Monte Carlo simulations. The contact value of the fluid-fluid radial distribution functions of the reference which is the key point of the perturbation process is derived as well, the comparison against Monte Carlo simulations shows that it has an excellent accuracy.

  1. Phase separation of binary nonadditive hard sphere fluid mixture confined in random porous media.

    PubMed

    Chen, W

    2013-10-21

    I analyze the fluid-fluid phase separation of nonadditive hard sphere fluid mixture absorbed in random porous media. An equation of state is derived by using the perturbation theory to this complex system with quenched disorders. The results of this theory are in good agreement with those obtained from semi-grand canonical ensemble Monte Carlo simulations. The contact value of the fluid-fluid radial distribution functions of the reference which is the key point of the perturbation process is derived as well, the comparison against Monte Carlo simulations shows that it has an excellent accuracy. PMID:24160538

  2. Hard target UV lidar measurements of isoprene mixing ratios and emission rates from eucalyptus trees.

    PubMed

    Roberts, David Edward; Du Plessis, Anton; Ombinda-Lemboumba, Saturnin

    2007-09-01

    The application of UV lidar to measure isoprene concentrations for environmental studies has been investigated. With a hard target lidar system at 223 nm, isoprene mixing ratios above eucalyptus trees were measured with a sensitivity of about 1 ppbv. Results over a long timescale were compared with an existing model of isoprene emission for a wide range of temperature and sunlight values. Fast time dependent results yielded a leaf emission rate of 25 microg g(-1) hour(-1), consistent with emission from other eucalyptus species. Requirements for development of the system for range resolved isoprene number density measurements using atmospheric backscatter lidar are discussed. PMID:17805372

  3. Communication Considerations for Parents of Deaf and Hard-of-Hearing Children

    MedlinePLUS

    ... Parents of Deaf and Hard-of-Hearing Children Communication Considerations for Parents of Deaf and Hard-of- ... people have debated the best ways to develop communication skills and provide education for deaf and hard- ...

  4. 77 FR 34073 - Value Engineering

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ...of Federal Procurement Policy Value Engineering AGENCY: Office of Federal Procurement...Budget Circular No. A-131, ``Value Engineering...revise OMB Circular A- 131, Value Engineering, to update and reinforce policies...

  5. The effect of water hardness on the toxicity of uranium to a tropical freshwater alga Chlorella sp.

    PubMed

    Charles, Amanda L; Markich, Scott J; Stauber, Jennifer L; De Filippis, Lou F

    2002-10-01

    Uranium (U) derived from mining activities is of potential ecotoxicological concern to freshwater biota in tropical northern Australia. Few data are available on the effects of water hardness (Ca and/or Mg), which is elevated in U mine wastewaters, on the toxicity and bioavailability of U to freshwater biota, particularly algae. This study determined the effect of water hardness (8, 40, 100 and 400 mg CaCO(3) x l(-1), added as calcium (Ca) and magnesium (Mg) sulphate) on the toxicity (72 h growth rate inhibition) of U to the unicellular green alga, Chlorella sp., in synthetic freshwater, at constant pH (7.0) and alkalinity (8 mg CaCO(3) x l(-1)), similar in chemical composition to sandy coastal streams in tropical northern Australia. A 50-fold increase in water hardness resulted in a 5-fold decrease (Phardness includes: (i) competition between U and Ca and/or Mg for binding sites on the cell surface; and (ii) a change in U speciation, and hence, bioavailability. Results showed that extracellular (cell-surface) and intracellular U concentrations significantly (P<0.05) decreased (2-5-fold) as water hardness increased from 8 to 400 mg CaCO(3)x l(-1). Calculation of U speciation using the geochemical model HARPHRQ showed that there were no significant (P>0.05) differences in the predicted speciation (% distribution) of U amongst the four water hardness levels. The reduction in U toxicity with increasing water hardness was most likely due to competition between U and Ca and/or Mg for binding sites on the algal cell surface. The minimum detectable effect concentrations of U were approximately 3 and 24 times higher (at 8 and 400 mg CaCO(3)x l(-1) hardness, respectively) than the national interim U guideline value (0.5 micro g x l(-1)) for protecting aquatic ecosystems. Overall, the results reinforce the need for a more flexible U guideline based on a hardness-dependent algorithm, which may allow environmental managers to relax the national guideline for U on a site-specific basis. PMID:12204587

  6. Vector-valued Malvar wavelets

    NASA Astrophysics Data System (ADS)

    Xia, Xiang-Gen; Suter, Bruce W.; Huang, Ying

    1996-06-01

    Scalar-valued Malvar wavelets have been used to eliminate the blocking effects in scalar transform coding. In this paper, we introduce vector-valued Malvar wavelets for vector-valued signals. While constructing window vectors, we present a connection between vector-valued Malvar wavelets and vector Lemarie-Meyer band-limited wavelets. Similar to scalar-valued Malvar wavelets, vector-valued Malvar wavelets have applications in eliminating the blocking effects in vector transform coding.

  7. Maximally Random Jamming of Two-Dimensional One-Component and Binary Hard Disc Fluids

    E-print Network

    Xinliang Xu; Stuart A. Rice

    2010-10-05

    We report calculations of the density of maximally random jamming (aka random close packing) of one-component and binary hard disc fluids. The theoretical structure used provides a common framework for description of the hard disc liquid to hexatic, the liquid to hexagonal crystal and the liquid-to-maximally random jammed state transitions. Our analysis is based on locating a particular bifurcation of the solutions of the integral equation for the inhomogeneous single particle density at the transition between different spatial structures. The bifurcation of solutions we study is initiated from the dense metastable fluid, and we associate it with the limit of stability of the fluid, which we identify with the transition from the metastable fluid to a maximally random jammed state. For the one-component hard disc fluid the predicted packing fraction at which the metastable fluid to maximally random jammed state transition occurs is 0.84, in excellent agreement with the experimental value 0.84 \\pm 0.02. The corresponding analysis of the limit of stability of a binary hard disc fluid with specified disc diameter ratio and disc composition requires extra approximations in the representations of the direct correlation function, the equation of state, and the number of order parameters accounted for. Keeping only the order parameter identified with the largest peak in the structure factor of the highest density regular lattice with the same disc diameter ratio and disc composition as the binary fluid, the predicted density of maximally random jamming is found to be 0.84 to 0.87, depending on the equation of state used, and very weakly dependent on the ratio of disc diameters and the fluid composition, in agreement with both experimental data and computer simulation data.

  8. Energy and American values

    SciTech Connect

    Barbour, I.; Brooks, H.; Lakoff, S.; Opie, J.

    1982-01-01

    A multi-disciplinary team consisting of an engineer, a political scientist, an historian, and a professor of religion and physics view the question of energy and values from each other's perspective. The result is a synthesis of the team's views on all aspects of energy technology and how it affects human life in general as well as the lives of different classes and specific groups in our society. It begins with an historic overview of the way an abundance of energy has shaped America's use of it. It continues by considering the energy debate as a conflict between Jeffersonians who believe in decentralized, appropriate technology and the centralized, efficient technology of Hamiltonians. The authors wrestle with regional and geographical differences in energy resources, environmental impacts, and ethical problems. 384 references.

  9. AeSPoe HARD ROCK LABORATORY

    SciTech Connect

    Svemar, C; Pettersson, S.; Hedman, T.

    2003-02-27

    Aespoe Hard Rock Laboratory (AEHRL) has been constructed in virgin bedrock as part of the development of a deep geological repository for spent nuclear fuel in Sweden, the role being to provide input to the performance assessment, to test engineered barrier systems and to develop and refine full scale methods and machines for construction and operation of the real repository. The AEHRL extends down to 460 m depth with access via both ramp and shaft. Work in the laboratory has been separated into 4 different stage goals: (1) Verification of site investigation methods. (2) Development of detailed investigation methodology. (3) Testing of models for description of the barrier function of the host rock. (4) Demonstration of technology for and function of important parts of the repository system Stage goals 1 and 2 were in focus during the period 1986-95 and are now completed. Stage goal 1 concerns investigations carried out from ground surface and stage goal 2 investigations carried out underground, in this case during excavation of the ramp. The present work is focused on the two operative stage goals 3 and 4. The activities on barrier function of the host rock comprises primarily in-situ tests with tracer migration in natural fractures and migration of actinides in small samples of rock or bentonite inside a chemical laboratory probe installed in a borehole. The data collected from the tests are used for model development and verification. The demonstration of technology includes studies of engineered barriers and comprises tests of copper stability, bentonite buffer, backfill, plugging and practical development of the main disposal sequences. Up today five full scale deposition holes with buffer and canister, and one full-scale test of backfill and plugging have been installed. The prototype for the deposition machine is in operation. The work is conducted in an international environment and altogether eight organizations from seven countries besides Sweden take part in the AEHRL program. The paper concludes the results from the stage goals 1 and 2, and presents the projects conducted within the stage goals 3 and 4 as well as conclusions drawn from available results.

  10. Implementation and Implications of a Stealth Hard-Drive Backdoor

    E-print Network

    Paris-Sud XI, Université de

    Implementation and Implications of a Stealth Hard-Drive Backdoor Jonas Zaddach Anil Kurmus Davide present a stealth rootkit that replaces arbitrary blocks from the disk while they are written, providing

  11. Chemical bonding in hard boron-nitride multilayers

    SciTech Connect

    Jankowski, A.F.; Hayes, J.P.

    1997-06-01

    The oxides and nitrides of boron show great potential for use as hard, wear resistant materials. However, large intrinsic stresses and poor adhesion often accompany the hard coatings as found for the cubic boron-nitride phase. These effects may be moderated for use of a layered structure. Alternate stiff layers of boron and compliant layers of nitride are formed by modulating the sputter gas composition during deposition of boron target. The B/BN thin films are characterized with transmission electronic microscope to evaluate the microstructure, nanoindentation to measure hardness and ex-ray absorption spectroscopy to determine chemical bonding. The effects of layer pair spacing on chemical bonding and hardness are evaluated for the B/BN films.

  12. Low voltage vertical recording preamplifier for hard disk drives

    E-print Network

    Mellachervu, Ramachandra Murthy

    2004-11-15

    Higher data rate hard disk drives(HDD) and improved read channel electronics are demanding preampli?er performance be extended well beyond 1 Gb/s. Historically, preampli?er power requirements were of low priority; however...

  13. Remote hard copy. Volume 3. Systems programming manual

    SciTech Connect

    Simons, R.W.

    1980-03-01

    The software used to operate and maintain the remote hard copy is described. All operating software that runs in the NOVA minicomputers is covered as are various utility and diagnostic programs used for creating and checking this software. 2 figures.

  14. Development of creep curves from hot indentation hardness data

    SciTech Connect

    Kutty, T.R.G.; Ganguly, C. [Bhabha Atomic Research Centre, Bombay (India). Radiometallurgy Div.] [Bhabha Atomic Research Centre, Bombay (India). Radiometallurgy Div.; Sastry, D.H. [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy] [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy

    1996-06-15

    Indentation creep is defined as time dependent motion of a hard indenter into a solid under constant load and temperature. This technique is particularly advantageous for health hazardous radioactive nuclear materials since small samples are required for this test and a large number of data could be generated on the same sample. The only requirement for evaluation of indentation hardness and creep is a metallographically polished specimen surface. Several investigators have correlated hot hardness with creep and have estimated activation energy for creep and stress exponent for steady state creep rate. The aim of the present work is to evaluate hot hardness and in turn creep behavior of U-Zr alloy fuels containing 5, 10 and 15 wt.% of Zr and fuel cladding materials namely stainless steel (type 316) and zircaloy-2.

  15. Innovation incentives and competition in the hard disk drive industry

    E-print Network

    Wu, Xiaohua Sherry

    2011-01-01

    Firms in the hard disk drive industry are continually engaging in R & D and improving the quality of their products. We explore various determinants of the product innovation incentives for firms concerned with both their ...

  16. Crystalline assembly of hard polyhedra via directional entropic forces

    NASA Astrophysics Data System (ADS)

    Damasceno, Pablo F.; Engel, Michael; Glotzer, Sharon C.

    2012-02-01

    Entropic forces are effective forces that result from a system's statistical tendency to increase its entropy. Hard rods and disks spontaneously align and can assemble into layers and columns if those structures increase the configurational space available to the particles. Hard spheres, cubes and even tetrahedra order for the same reason. Here we extend those findings by showing that hard polyhedra can self-assemble into a variety of complex phases, most of them never before reported in systems of single-component hard particles. The role of shape and directional entropic forces in stabilizing these structures will be discussed. Our results suggest new possibilities for self-assembling complex target structures from colloidal building blocks. [4pt] [1] Damasceno, PF; Engel, M; Glotzer, SC. arXiv:1109.1323v1

  17. How to estimate hardness of crystals on a pocket calculator

    SciTech Connect

    Simunek, Antonin [Institute of Physics v.v.i., Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 162 53 Prague (Czech Republic)

    2007-05-01

    A generalization of the semiempirical microscopic model of hardness is presented and applied to currently studied borides, carbides, and nitrides of heavy transition metals. The hardness of OsB, OsC, OsN, PtN, RuC, RuB{sub 2}, ReB{sub 2}, OsB{sub 2}, IrN{sub 2}, PtN{sub 2}, and OsN{sub 2} crystals in various structural phases is predicted. It is found that none of the transition metal crystals is superhard, i.e., with hardness greater than 40 GPa. The presented method provides materials researchers with a practical tool in the search for new hard materials.

  18. Why Are Bad Products So Hard to Kill?

    E-print Network

    Simester, Duncan

    It is puzzling that firms often continue to invest in product development projects when they should know that demand will be low. We argue that bad products are hard to kill because firms face an inherent conflict when ...

  19. Converting Hard Copy Documents for Electronic Dissemination Forrest Hoffman

    E-print Network

    Hoffman, Forrest M.

    in an organization is far from totally auto­ mated, particularly for items requiring signatures or authorizations to spiffy marketing brochures, was previously published only in hard copy. Converting existing documents

  20. Optimal Auction Design for Agents with Hard Valuation Problems

    E-print Network

    Chen, Yiling

    Optimal Auction Design for Agents with Hard Valuation Problems David C. Parkes ? Computer human expert. Although auction design cannot simplify the valuation problem itself, we show that good. Keywords: agent-mediated electronic commerce, valuation problem, metade- liberation, auction theory